THE HISTORY OF DREDGING IN
CLEVELAND BAY, QUEENSLAND
AND ITS EFFECT ON SEDIMENT
MOVEMENT AND ON THE
GROWTH OF MANGROVES,
CORALS AND SEAGRASS.
Ada W Pringle (nee Phillips)
Department of Geography
University of Lancaster, U.K.
ft2j d ~
TOWNSVILLE PORT AUTHORITY
~ Great Barrier Reef Marine Park Authority
© Commonwealth of Australia
ISBN 0 64212034 X
Produced by GBRMPA
September 1989
The opinions expressed in this document are not
necessarily those of the Great 8arrier Reef Marine
Park Authority or the Townsville Port Authority
~ Great Barrier Reef• Marine ParkAuthority
P.O. Box 1379
Townsville Qld 4810
Telephone (077) 818811
EXECUTIVE SUMMARY
Aims
The aims of this project on Cleveland Bay were to investigate:
1) the history of dredging using all available Townsville
Port Authority records and records from other relevant
sources; attention was to be focussed on the location of
dredging and dumping and the types of material involved,
2) coastal changes as revealed by aerial surveys between
1941 and 19B8 and a more limited number of replicate
ground surveys,
3) processes influencing sediment movement both in the
coastal catchments which supply sediment to the bay, and
in the marine zone,
4) the relationship between dredging and the coastal changes
identified on the aerial photographs and ground surveys,
taking into account processes in the coastal catchments
and the marine zone.
Dredging Records
These are examined chronologically from the small scale
beginnings of dredging in 1883 when the port of Townsville was
starting to emerge, through its important role in the port's
sUbsequent development. For further consideration the records
were grouped into two time periods:
I883-IY64 Only intermittent data are available concerning
localities, depths and quantities dredged. Additional
problems arise from the use of different volume units which
proved impossible to convert, and a severe shortage of dump
site information. The only written records relate to dumping
near Cockle Bay, Magnetic Island in 1883 and 1893, and verbal
information suggests that dumping south of Middle Reef
occurred before the mid 1960's. More lithified dredge spoil
from developmental dredging especially in the harbour area
would be less liable to redistribution from the dump sites
than is the unconsolidated finer sediment from subsequent
maintenance dredging. Some of the latter has probably been
moved by currents (although only a partial knowledge of these
exists at present) onto the south-west Magnetic Island coral
reef flat.
1965-1988 From 1965 onwards Townsville Port Authority
dredging records give details of each dredged load including
source. The data have been tabulated to show monthly and
annual totals dredged from different parts of the port and
approach channel; graphs have been drawn also from this data.
During a massive programme of developmental and maintenance
dredging in the early and mid 197D's the annual maximum
reached 2,112,879 tonnes in 1973-74. A shallow draft dump
site south-east of Magnetic Island has been used since the
1960's and a deep draft dump site east of Magnetic Island
since the early 1970's. Fine sediment from the 1970's
developmental dredging which was dumped mainly at the latter
site was probably extensively redistributed by currents.
Coastal and Nearshore Zone Changes
Vertical aerial surveys at various scales and time intervals
between 1941 and 1988 were analyzed to determine coastal and
nearshore zone changes. The longer time intervals, up to a 17
year maximum, during the 1940's, 1950's and 1960's contrast
with the regular 3-4 year interval between surveys in the
1970's and 1980's. The surveys selected for analysis were
those which provided an extensive cover of the Cleveland 8ay
area, most commonly at a scale of 1:12,000 and which show
clearly coastal and nearshore features. The Cleveland Bay and
Magnetic Island coasts were divided into segments for analysis
and assessment of change in the physical features, mangroves,
fringing coral reefs and seagrass beds. Several of these
segments showed relatively little change during this period.
The most marked changes occurred along the Ross River delta
segment; at localities where seagrass beds are found in the
intertidal and subtidal zones off Shelly Beach-Cape
Pallarenda, Sandfly Creek-Cape Cleveland and the south-west
coast of Maqnetic Island: and in the manQrove frinQe of this
same Magnetic Island segment.
Coastal ground surveys have been much more limited in
scope and frequency than the aerial surveys. Replicate
surveys by the Beach Protection Authority in 1982 and 1983
along the Cleveland Bay coast west of Townsville Harbour and
along parts of the south-east and north coasts of Magnetic
Island were studied, as were 6 replicate surveys by the
Townsville Port Authority between 1978 and 1983 along cross
profile lines ~etween Townsville Harbour and Cape Pallarenda.
Only small scale vertical changes (O.I-0.2m accretion or
erosion) were revealed by these surveys.
Processes Influencing Sediment Movement
In order to assess the possible effect of dredging on
these coastal and nearshore zone changes the processes
influencing sediment movement are reviewed. Within the
coastal catchments, geology, climate and river regime are
considered as the main influences on natural sediment supply
to the coast. Man's intervention through engineering works,
such as dams and wei rs and by pollution are exami ned also.
Marine processes relating to wind, wave and tidal effects are
assessed in so far as they influence sediment movement over
the sea bed and in suspension.
Relationship between Oredging and Coastal Change
The most direct effect of dredging has been shown near
the mouth of Ross River. Here 2.319.660m3 of sand were
removed from the intertidal sand~anks between 1968 and 1970
and a further 4UO.OOOm J were removed from the nearbv Ross
River bed in 1979-80 for adjacent land reclamation.
was removed during developmental dredging in the Ross
channel between 1977 and the early 198U's and during
More sand
River
subsequent maintenance dredging. Two effects have resulted.
Firstly the channel has been moved westwards from its previous
natural route across the intertidal zone, which has ~ffected
the sedimentation pattern. Secondly this sediment which has
been shown to be heavily polluted from the former sewage
outfall on the east side of the Ross River mouth has been used
in land reclamation and some has been carried to the shallow
draft dump site south-east of Magnetic Island from where it
will have been redistributed in response to current movements.
Dredging probably produced its greatest and most widely
felt effect in the early to mid 1970's, although this is more
difficult to demonstrate as it occurred at the same time as
major natural events. During this period there was a massive
programme of developmental as well as routine maintenance
dredging. The highest monthly peak rose to over 118,OUO
tonnes in October 1972. The maximum annual peak of over
2,000,000 tonnes in 1973-74 is equivalent to nearly two thirds
of the Burdekin River's estimated averge washload plus bedload
of 3.45 million tonnes. The predominantly fine dredged
sediment was dumped mainly in the deep draft dump site, but
with some in the shallow draft dump site, and after
redistribution by currents, it probably had a marked adverse
effect on the Cleveland Bay seagrass beds. The aerial surveys
showed a moderate seagrass cover in 1959 and 1961, almost no
seagrass in 1974, but recovery beginning by 1978 and
continuing through 1981 to 1985. A gap in appropriate aerial
surveys in the 1960's and early 1970's makes pinpointing the
time of the seagrass destruction difficult. However it is
likely to have occurred in the early 1970's when the massive
dredging programme coincided with the occurrence of Cyclones
'Althea' and 'Una' and subsequent periods of heavy rain. These
produced major floods down the rivers leading into Cleveland
Bay and down the Burdekin River which also can affect the bay
at such times. The massive influx of sediment from dredging
and river floods probably produced extensive burial of
seagrass beds. It also may have contributed to mangrove
deaths noted along the south-west Magnetic Island coast during
this period.
Future Assessment of Dredging Effects
To assess dredging effects in Cleveland Bay more precisely in
the future further monitoring and research is proposed:
- detailed recording of localities of dredging, amounts
and types of material dredged and localities of
dumping; further observation of dredge spoil plumes
under different wind, wave and tidal conditions,
- more detailed instrumental measurements of tides, tidal
currents, regional winds and waves to provide a better
understanding of processes affecting sediment
movements,
- monitoring of all major types of coastal change
considered in this report and analysis of the recorded
changes in the light of the controlling processes and
the dredging programme.
CONTENTS
Page
List of Tables vii
List of Figures vii i
List of Plates xi
Acknowledgements xii
Introduction
Chapter 1 History of Dredging in Cleveland Bay.
Chapter 2 Coastal and Nearshore Zone Changes
in the Cleveland Bay Area.
Chapter 3 Processes Influencing Sediment
Movement in Cleveland Bay.
Chapter 4 An Assessment of the Influence of
Dredging on Sediment Movement, and
Growth of Mangroves, Corals and
Seagrass in Cleveland Bay.
Chapter 5 Conclusions.
References
Appendix
Tables
Figures
Plates
1
5
25
40
57
72
7B
ll2
90
126
174
LIST OF TABLES
1
2
3
4
5
6
7
9
1U
11
12
13
14
Dredged depths at Port of Townsville 1884-1987.
All dredging records for Port of Townsville
1889-1965 and for T.S.D. 'Sir Thomas Hiley'
1974-1976.
Townsville Port Authority monthly dredging
records for S.D. 'Townsville', 1965-1983.
Townsville Port Authority dredging records
1983-1988 for T.S.D. 'Sir Thomas Hiley'.
Aerial Photographs used in this report.
Beach Protection Authority cross profiles
- summary of changes.
Townsville Port Authority cross profiles
- summary of changes.
Townsville rainfall records. Bureau of
Meteorology data for Townsville Pilot Station
1871-1940 and Townsville Airport 1941-.
Queensland Water Resources Commission monthly
and annual volumes and annual runoff for:
a} Ross River at Ross River Dam headwater
b) Alligator Creek at Allendale
c) Black River at Bruce Highway.
Tropical cyclones affecting the Burdekin Delta
area and major Burdekin River floods 1940-1980.
Cape Cleveland, percentage occurrence of wind
speed versus direction based on 30 years of
Bureau of Meteorology records.
Monthly wave statistics for wave buoy near
Cape Clevel and.
Annual wave statistics for wave buoy near Cape
Cleveland, for calender years and dredging years
(ending 30 June).
Wave statistics, wave period/wave height
occurrences at wave buoy near Cape Cleveland:
a} All data, all directions
b} Summer data, all directions
c) Winter data, all directions.
Page
91
94
96
102
103
104
106
107
110
113
114
117
122
123
LIST OF FIGURES
Page
130
127
128
129
131
135
134
132
4
3
5
1
2
7
6
8
Location map.
Nisbet's plan showing progress of harbour works,
1885.
View of harbour showing proposed improvements as
adopted by Townsville Harbour Board, 1897.
Townsville Port Authority annual dredging records
September 1965 to February 1983 for S.D.
'Townsville' and July 1983 to August 1988 for
T.S.D. 'Sir Thomas Hiley'.
Townsville Port Authority monthly dredging records
September 1965 to February 1983 for S.D.
'Townsville'.
Maps of coastal area between Shelly Beach and Cape
Pa11arenda drawn from aerial photographs taken in
1959, 1974, 1981 and 1985.
Map of coast between Cape Pa11arenda and Ross Creek
drawn from aerial photographs taken in 1985.
Maps of coast between Ross River and Sandf1y Creek
drawn from aerial photographs taken in 1959, 1974,
1981 and 1985.
9 Shoreline changes in the Ross River to Sandf1y Creek 137
area 1941-1973. (After McIntyre and Associates,1974).
10 Maps of coast between Sandf1y Creek and Cape 138
Cleveland drawn from aerial photographs taken in
1974, 1978, 1981 and 1985.
11 Shoreline changes in south Cleveland Bay between 140
Sand fly Creek and Cocoa Creek 1941-1973. (After
McIntyre and Associates, 1974).
12 Coastal features of Magnetic Is1 and. 141
13 Maps of south-west coast of Magnetic Island drawn 142
from aerial photographs taken in 1959, 1974, 1978,
1981 and 1985.
14 Maps showing location of Beach Protection Authority 144
cross profile lines between Townsville Harbour and
Shelly Beach and on Magnetic Island.
LIST OF FIGURES continued
15
16
17
18
19
20
Map showing location of Townsville Port Authority
cross profile lines between Townsville Harbour and
Cape Pall arenda.
Townsville annual rainfall 1870-1987.
Queensland Water Quality Council's Cleveland Bay
sediment pollution study:
a) Sediment sampling site locations
b) Percentage <0.063mm fraction in sediments
c) Escherichia coli in sediments
d) Coprostanol
e) Phosphorus
f) Bicarbonate extractable phosphorus
g) Acid extractable phosphorus
h) Oi 1 and grease
i) Escherichia coli, coprostanol and acid
extractable phosphorus.
Annual records of wave height (Hsig) and wave
period (Tp) at wave buoy near Cape Cleveland
1975-1987.
Wave records from wave buoy near Cape
Cleveland 19.11. 75-29.12.87:
a) Histogram showing percentage (of time)
occurrence of wave heights (Hsig) for all
wave periods (Tp)
b) Historgam showing percentage (of time)
occurrence of wave periods (Tp) for all
wave heights (Hsig).
Cleveland Bay wave refraction diagrams
(after McIntyre and Associates, 1974):
a) For south-east waves with 5 second period
b) For easterly waves with 5 second period
c) For north-east waves with 5 second period.
Drogue measurements by Townsville Port
Authority:
a) Flood tidal currents
b) Ebb tidal currents.
Page
146
147
148
153
160
162
165
LIST OF FIGURES continued
22
23
24
25
Release and retrieval points for Woodhead
sea-bed drifters, and schematic transport
paths (after Belperio, 1978).
Distribution of surface suspended sediment
in Cleveland Bay (after Belperio, 1978):
a) For sea conditions smooth and smooth-slight
b) For sea conditions slight and slight
-moderate
c) For sea conditions moderate and moderate-
rough
d) For rough sea conditions.
a) Isopachs of dredge spoil distribution
within Cleveland Bay as inferred from
vibracores
b) Surficial sediment facies distribution
within Cleveland Bay beneath dredge spoil
(after Carter and Johnson 1987).
Seagrass distribution in the Cleveland Bay area.
Draft maps from Northern Fisheries Research
Centre, Queensland Department of Primary
Industries.
Page
167
168
169
170
LIST OF PLATES
1
2
3
4
5
6
Bucket Oredge 'Octopus' dredging Ross Creek
in 1901.
Suction Dredge 'Morwong' in October 1946.
Suction Dredge 'Townsville' maintaining depths
in the Swing Basin.
Bucket dredge 'Cleveland Bay' in 1964 on her
final assignment, dredging the new oil and
tanker berth.
Trailer Suction Dredge 'Sir Thomas Hiley'
carrying out developmental dredging in the
Swing Basin in 1973.
Trailer Suction Dredge 'Sir Thomas Hiley'
carrying out maintenance dredging in the
Swing Basin in June 1988.
Page
175
175
176
176
177
177
ACKNOWLEDGEMENTS
I am pleased to acknowledge the assistance of the following
in supplying material which has been used in the preparation of
this report: the Townsville Port Authority especially Mr Bill
Service and his staff in the Engineer's Department, particularly
Messrs John Neal and Neil Butterworth, also Mr Barry Holden,
Secretary, and Mr H J Taylor retired Secretary of the Authority;
Associate Professor David Hopley, Head of the Sir George Fisher
Centre for Tropical Marine Studies at James Cook University and
his staff, especially Mr A Diamond and Mr Paul Muir who assisted
with wave data analysis; staff of the Geography Department and Dr
John Collins of the Biological Sciences Department at James Cook
University; Townsville City Council Engineering and Planning
Departments; Sunmap; Queensland Water Resources Commission at
Clare; Bureau of Meteorology in Townsville and Brisbane;
Or E Gustavson of the Queensland Water Quality Council,
Townsville; Dr G Jones of the Townsville and Thuringowa Water
Board; Dr E Wolanski of the Australian Institute of Marine
Sciences; Mr John Dobson and the Librarian of the Port of
Brisbane Authority; the Queensland State Library and Oxley
Library, Brisbane; the Beach Protection Authority of the
Queensland Department of Harbours and Marine, Brisbane;
Dr R G Coles, Dr Warren Lee Long and Ms Jane Mellors of the
Queensland Department of Primary Industries' Northern Fisheries
Research Centre, Cairns; British Admiralty Hydrographic
Department, Taunton, U.K.
I should like to thank also Ms Claudia Baldwin and
Mr John Gillies of the Great Barrier Reef Marine Park Authority
for their efficient and friendly guidance over the project;
Mrs Marlene McNaught for typing the report and Miss Claire Jarvis
for drawing all the original maps and diagrams, in the Geography
Department at Lancaster University; and my husband George for
assistance with fieldwork and data collection in Queensland and
for preparing for the report the maps, diagrams and tables from
secondary sources. He also took the photograph for Plate 6 and
the remainder of the Plates are from H.J. Taylor's 'The History of
Townsville Harbour 1864-1979', published in 1980 by Boolarong
Press, Fortitude Valley, Queensland for Townsville Harbour Board.
INTRODUCTION
Aims
This report investigates the history of dredging in
Cleveland Bay and aims to assess its influence on sediment
movement and on the growth of mangroves, fringing coral reefs
and seagrass. The history of dredging will be traced from
its small scale beginnings in 1883, when the port of
Townsville was starting to emerge, through its important role
in the subsequent development of the port. Attention will be
focused on the location of dredging, the amount and types of
material dredged and the dump sites used for its disposal.
All available Townsville Port Authority records have been
used, together with records from the Queensland Department of
Harbours and Marine (and its predecessors) and Port of
Brisbane Authority, in so far as they relate to dredging in
the Port of Townsville.
Assessment of the influence of dredging wil.l be made in
relation to changes identified on a series of aerial surveys
flown between 1941 and 1988. Changes shown on a limited
number of replicate coastal ground surveys, carried out by
the Beach Protection Authority and the Townsville Port
Authority, will be considered also. Such an assessment must
take into account the natural processes operating in the
area. Here the processes operating in the coastal catchments
relating to geology, climate, and river regime will be
examined in so far as they influence fluvial sediment supply
to the coast. Man's intervention in the natural sediment
supply system and his pollution of parts of it will be
considered as well. Marine processes relating to wind, wave
and tidal conditions will be examined, concentrating
especially on their effects on sediment movement both over
the sea-bed and in suspension.
Because of limitations in the earlier dredging records
between 1883 and 1964 only a broad general assessment of the
effects of dredging can be made for this period. The
1
existence of much more detailed dredging records and data
relating to processes enables a more detailed assessment to
be made for the subsequent period between 1965 and 1988.
Separate consideration will be 9iven then to coastal and
intertidal zone changes, and changes to the mangrove coasts,
the fringing coral reefs and the seagrass beds, which extend
from the intertidal zone into adjacent parts of the subtidal
zone.
Cleveland Bay Area
Cleveland Bay located at about latitude 19°5. is
approximately 17km square and faces north-eastwards to the
Coral Sea (Figure 1). On its north-west side is Magnetic
Island which is separated from the adjacent mainland by the
narrow and shallow West Channel. The 15m isobath lies across
the entrance to the bay with the 10m isobath approximately
parallel to it on its landward side. A channel, which Carter
and Johnson (1987) named Orchard Channel, runs parallel to
the north-east coast of Magnetic Island and these isobaths
swing south round it. The central and southern parts of the
bay slope gently landwards. West Channel in its shallowest
central part is under 4m depth with the elongated Middle Reef
rising above Low Water Mark (LWM) on its south side.
Townsville Harbour has been sited on the south-west coast of
Cleveland Bay with the artificial Platypus Channel, the main
approach channel for shipping, extending northwards from it
and terminating in the dog-leg Sea Channel off the south-east
coast of Magnetic Island.
The coast of Cleveland Bay is mainly depositional in
type but with the granite and volcanic rock headlands of Cape
Pallarenda and Cape Cleveland bounding it on its western and
eastern sides repectively, and Kissing Point forming a low
granite promontory on the south-west coast. ~eagrass has
colonized on an intertidal and subtidal foreland north of
Cape Pallarenda. A series of beach ridges flank the west
coast of the bay, which has a narrow sand beach backed by low
sand dunes. The south-east coast between Kissing Point and
2
Townsville harbour is backed by an artificial wall of large
rocks to protect The Strand in Townsville from coastal
erosion, and only a narrow sand beach lies at its foot. The
mouths of Ross River and its distributary Ross Creek now form
part of the Port of Townsville with the harbour extending
seawards between them. Previously this area was part of the
aggrading Ross River delta, which extends westwards to the
mouth of Sandfly Creek. A series of beach ridges have
developed here as the coast extended seaward. Further east,
along the south coast of Cleveland Bay a beach ridge and
chenier plain has formed north of the Muntalunga Range, with
narrow sand ridges interspersed by salt flats with saltmarsh
along their margins. Alligator, Crocodile and Cocoa Creeks
flow in meandering courses across this plain. Along the
whole coast eastwards from near the Ross River mouth to the
southern end of Cape Cleveland a strip of mangroves straddles
High Water Mark (HWM) and is flanked by an intertidal zone of
fine silty sand. Along the west coast of Cape Cleveland,
rock headlands separate sandy bayhead beaches, with mangroves
colonizing in the most sheltered localities. In the lower
part of the intertidal zone and the adjacent part of the
subtidal zone along the south and east coasts of the bay,
extensive seagrass beds have_developed.
The triangular shaped Magnetic Island is formed mainly
of granite with volcanic rocks outcropping near West Point.
The north and south-east facing coasts consist of rock
headlands, with bays between containing sandy bayhead
beaches. In the most sheltered localities fringing coral
reefs have formed and these are best developed in Geoffrey,
Nelly and Picnic Bays on the south-east coast. The
south-west coast flanks West Channel and gains maximum
shelter from the prevailing south-east~inds and waves. Here
the largest fringing coral reef is found and landwards a belt
of mangroves has developed near HWM. Seagrass grows in
sediment on the reef flat.
3
Units of Measurement
Inevitably in records such as those relating to dredging
which span a period of over 100 years, different units have
been used at different times. In addition to imperial and
metric units which may be converted readily, other units, eg
barge yards, were used, the precise meaning of which has
proved impossible to determine. For uniformity of treatment
within Chapter 1 concerned with the 'History of Dredging in
Cleveland Bay' the original units are retained as used in the
Townsville Port Authority records and in the various reports
and books referred to. This also should assist those. readers
who wish to refer back to the source material. Elsewhere in
the report, in the text, tables and figures metric
measurements are used except where conversion proved
impossible.
4
CHAPTER 1
History of Dredging in Cleveland Bay
The history of dredging in Cleveland Bay is closely
linked to the development of the Port of Townsville. In 1864
(Department of Harbours & Marine Queensland,1986) J.M. Black,
North Queensland Manager of the Sydney firm of Robert Towns
and Company selected a site on Ross Creek for a harbour
needed in the development of pastoral properties in the
hinterland. However, a sand bar at the mouth of Ross Creek
and a rock bar inside allowed only shallow draught vessels to
enter at H.W. The amount of shipping in Cleveland Bay
doubled between 1867 and 1868 with the opening up of the Cape
River goldfield. It was subsequently proposed in 1876 that,
in the absence of a suitable site on Ross Creek, a jetty
should be built from Magazine Island to form the basis of a
good harbour for Cleveland Bay and also to protect the
entrance to Ross Creek. The difficult work on this
progressed slowly in the late 1870's and early 1880's. At
the same time a western breakwater was being constructed
seaward to protect, and stop sand moving into, Ross Creek
from that side. The extent of the harbour works in 1885 are
shown on Nisbet's Plan (Taylor, 1980) (Figure 2).
1878-1890
Dredging was first proposed in 1878 (Annual Reports of
the Engineer of Harbours and Rivers on Works, 1876-1928) to
15-16ft below L.W.along the inside of the jetty and seaward.
In 1879 dredging was proposed in the Outer Harbour and also
to 18ft below L.W. in an approach channel 3,000-4,000ft long
aligned north to south. No silting was observed along the
jetty between 1880 and 1883 but dredging to increase the
water depth was again suggested. On 13 November 1883 the
dredge 'Platypus' from Brisbane began cutting a channel into
5
Ross Creek from Magazine Island Jetty in 12 ft of water at
L.W. "The material dredged is deposited close to Magnetic
Island, about 51/2 miles distant from where it is raised".
The material was mainly clay with sand and mud on top. The
'Platypus' continued to dredge this channel to 13ft below
L.W. from 1883 to 1887 and it was named the Platypus Channel.
In 1885 it was noted that a "light coating of sludge
accumulated" after dredging but no sand was deposited. In
November 1887 the 'Platypus' was sent to Cairns and replaced
by the dredge 'Octopus' from Brisbane, which continued
dredging the channel towards the rocks in the mouth of Ross
Creek through"extremely hard material".
After completing the channel in 1889 the 'Octopus' began
excavating a mooring basin in the shelter of the Eastern
Breakwater in "hard material", but soft sandstone gave way to
clay with increasing depth. In Ross Creek in 1890, 14.154cu
yards of material dredged from the planned swing basin was
transferred landwards for reclamation of the Palmer Street
frontage. A cyclone in March 1890 caused the deposition of
an "appreciable quantity" of silt over the dredged areas. and
a subsequent flood down Ross River carried much sand and
"levelled and distributed sandbanks" at the inner end of the
dredged channel.
1891-1900
In May 1891 the 'Octopus' continued excavating the basin
in the lee of the Eastern Breakwater. The earlier dredged
areas had silted up considerably with "sludge and soft mud".
but it could be removed relatively easily. The near
completion of the Western Breakwater caused accelerated scour
in the dredged channel and no further silting occurred there.
On 24 January 1892 a gale (probably associated with a
cyclone) produced "heavy seas" followed by "heavy floods"
down Ross Creek. which caused rapid siltation between the
6
breakwaters and east of the Eastern Breakwater. The
previously dredged channel depth of 10ft below L.W. was
reduced to 4ft, for a "considerable length". Dredging of the
basin in "difficult material" (sandstone, very tenacious clay
and mud) was almost complete in 1892 but re-dredging of the
channel was needed. In 1892 it was noted that "The cost of
carrying has ... been less, but this item will possibly be
slightly greater in the coming year as all the dredgings will
be carried to Cockle Bay, in Magnetic Island, it not being
advisable to deposit any eastward of the Eastern Breakwater".
The dredging plant in commission in June 1892 was the dredge
'Octopus', the two steam hopper barges 'Nautilus' and
'Dugong' and three side-delivery barges. The berth at the
railway wharf was excavated that month to 18ft below L.W.
Both developmental and maintenance dredging were carried
out between 1893 and 1901 (Annual Reports of the Marine
Department, 1894-1933; and Report of the Portmaster on the
Department of Ports and Harbours of Queensland 1882-1883).
In 1894 the basin near the railway wharf was deepened, but
gales in April led to floods which caused silting. Further
developmental dredging in all parts of the harbour was
undertaken in 1894-95, but between January and August 1885
maintenance dredging was necessary to remove soft mud which
had accumulated in all the previously dredged areas. The
Inner Harbour, in Ross Creek, had been subject to rapid
silting of bin/month at the wharf and 2-3in/month in the
entrance channel; 25% of the dredge's time was taken up in
clearing this. In 1895, the 'Octopus' was altered to enable
her to dredge to 30ft instead of 24ft as previously.
On 18 December 1896 the Queensland Department of
Harbours and Rivers formally handed over the dredge
'Octopus', the two steam hopper barges 'Nautilus' and
'Ougong' and silt punts numbers 26, 29 and 30 to the
Townsville Harbour Board, which thereafter was responsible
7
for dredging at the port. A considerable amount of
maintenance dredging was necessary during 1896-97, following
Cyclone 'Sigma' in January 1896 and a subsequent flood down
Ross Creek, which deposited much sediment in the harbour
especially towards the outer end of the Eastern Breakwater
(Department of Harbours and Marine Queensland, 1986).
In 1897, a scheme was put forward for harbour
improvements (Taylor 1980) (Figure 3) and was approved the
following year. By October 1899 the Platypus Channel had
been dredged to 17ft below Low Water Ordinary Spring Tides
(LWOST) and then the two bucket dredges 'Octopus' and
'Crocodile' were used inside the breakwaters and by 1900 had
dredged 58 acres down to this depth, with 4 acres along the
Eastern Breakwater wharves dredged to 26ft below LWOST.
656,000cu yards of spoil was removed during 1900. Excavation
of the Inner Harbour in Ross Creek also began in 1900 with
dredged material being ti~ped on the beach west of the
Western Breakwater for later reclamation there.
The sources used for the preceding review of dredging in
the 19th century give scattered information on quantities
removed and dredged depths, some of which have been
incorporated into the review. For easier reference and
sUbsequent analysis, this data is presented in full in tables
showing dredged depths in various parts of the Port of
Townsville (Table 1) and quantities dredged (Table 2).
Measurement of dredged depths were taken more systematically
in the 20th century as shown in Table 1. Quantities dredged
were recorded annually in the late 19th century, but no
records could be found for the period 1901-1941 and only
intermittent records could be found for the 1940's and 1950's
(Table 2). From September 1965 detailed records were kept by
the Townsville Harbour Board, later the Townsville Port
Authority, relating to its own dredge, (Table 3) and by the
Queensland Department of Harbours and Marine relating to its
8
dredges which were employed from time to time at Townsville
(Tables 2 & 4). Before these tables are considered in
detail, the history of dredging in Cleveland Bay in the 20th
century will be reviewed generally.
1901-1910
During the first decade of the 20th century
developmental and maintenance dredging occurred
simultaneously. The development of the Inner Harbour in Ross
Creek took 10 years, including the blasting of the rock bar
near the entrance to Ross Creek, the removal of the rubble by
dredge, and the dredging of the swing basin and berths
(Taylor, 198U). The Platypus Channel was steadily extended
and improved and the Outer Harbour swing basin and berths
were deepened. Maintenance dredging was vital to maintain
the depths of the cuttings. A cyclone in March 1903 led to
1-3ft of silting in the Platypus Channel and wharf
approaches. Another cyclone in 1908 caused siltation
problems and two floods in Ross Creek early in 1910 caused
deposition of large quantities of silt in the recently
dredged entrance to the Inner Harbour and in the Outer
Harbour (Department of Harbours and Marine Queensland, 1986).
The dredges 'Octopus' (Plate 1) and 'Crocodile', aided by a
Priestman grab dredge from 1904 onwards, were working at near
full capacity during this decade and in 191U a new dredge was
ordered. In 1906 quarterly soundings were instigated in the
Platypus Channel and the Outer Harbour and the annual June
data is given in Table 1.
1911-1920
On 7 July 1911 the new dredge 'Cleveland Bay' arrived in
Townsville from Paisley, Scotland, where it had been designed
and built with the capability of dredging to 38ft and raising
500 tons of stiff clay per hour (Taylor, 1980). The
9
'Crocodile' and 'Octopus' were in poor condition and the
latter was disposed of; the 'Crocodile' however was repaired
and refitted to upgrade it between 1913 and June 1914. In
1911 and 1912 the 'Cleveland Bay' which had electric light
worked two shifts in an 18 hour day to deepen berths in the
Outer Harbour. Developmental dredging in this part of the
port and in the Platypus Channel continued until 1919, with
"hard sandstone and stiff clay" making dredging difficult in
the Channel. Both dredges were involved in the developmental
and maintenance dredging the latter of which continued to be
important in retaining depths. In April 1919 all the
dredging plant was laid up due to the low revenue received by
the port, but in September the 'Cleveland Bay' was
recommissioned and undertook maintenance dredging in the
Platypus Channel until July 1920, aided by the 'Crocodile' in
the harbour approach channel in July 1919.
1921-1930
By 1921 the two bucket dredges had dredged the Platypus
Channel to 25.5ft, the swing basin and approach channel to
26ft and the Derths in the Outer Harbour to 30ft below LWOST
(Taylor, 19BO). However in June 1921 the 'Crocodile' was
finally taken out of commission due to the financially
depressed times. As Taylor observed "Dredging has always
been and forever will be the most essential of maintenance
works required at Townsville Harbour" yet for the following
30 years the 'Cleveland Bay' with its attendant barges and
tug was the one major plant to undertake this. Maintenance
dredging became of prime importance as the channel and berths
deteriorated due to silting. The Platypus Channel,
especially its inner east side, was subject to more siltation
than the rest of the harbour. Taylor argues that this was
because of the prevailing south-east winds and the discharge
of several creeks into Cleveland Bay on the east and
south-east side of the constructed harbour. Maintenance
10
dredging was therefore concentrated in the Platypus Channel.
The dredge's operations were limited during the summer
cyclone season and the policy was adopted of the plant being
laid up for overhaul, or operating inside the harbour, at
this time of year. Some developmental dredging was carried
out during the 1920's. The Outer Harbour swing basin was
extended and deepened although the dredging was described as
the hardest undertaken at Townsville because of the "stiff
clay, sandstone and boulder clay, impregnated with granite
boulders". Between 1923 and 1925 the dredging plant worked
to capacity on this and widening the Platypus Channel.
Between 192b and 1929 the only new work involved dredging an
approach channel and berth for the Jetty Wharf extension.
The Inner Harbour was dredged for 3 months in 1926-27. Up to
1925 there was some confusion over the declared depths in
various parts of the Port of Townsville, with some being
maximum, some minimum and some being between the two. From
1925 onwards only minimum depths were declared and these are
listed in Table 1.
1931-1940
Duri ng most of the 1930' s the 'c 1evel and Bay' was
employed in maintenance dredging, primarily in the Platypus
Channel but also in the swing basin and berths of the Outer
Harbour. For 4 months in 1936 dredging was carried out in
the Inner Harbour to remove large silt deposits from the
channel into Ross Creek and in the swing basin and slipway
approach (Taylor, 1980). In 1938 the 'Cleveland Bay'
operated two shifts in the Platypus Channel, berths and west
of the channel and undertook some developmental dredging in
the Outer Harbour for the Empire Flying Boat moorings (Annual
Reports of Queensland Department of Harbours and Marine
1934-1987). Two cyclones affected Cleveland Bay in 1940, on
18 February and a less severe one on 7 April. Considerable
damage was caused on Magnetic Island to bathing enclosures,
ferry landings and approaches especially at Alma and Nelly
11
Bays and to a slightly lesser degree at Picnic Bay and
Arcadia. Depths in the Platypus Channel were reduced to a
minimum of 22ft below LWOST on 18 April and 20 ft on 13 June,
with 20.5 ft being the minimum elsewhere in the dredged areas
of the Outer Harbour on 18 April (Taylor, 1980).
1941-1950
During World War II, Townsville was a very busy port.
The bucket dredge 'Cleveland Bay' operated two shifts of
maintenance dredging in 1941 in an attempt to obtain and
maintain the Platypus Channel and swing basin to 28ft below
LWOST, dredge the berths and keep the entrance channel to
Ross Creek open (Department of Harbours and Marine
Queensland, 1986). During part of 1941, the suction dredge
'Trinity Bay' owned by the Cairns Harbour Board assisted in
dredging the Platypus Channel. Between February and May 1942
an Allied Works Council Scheme was commenced to provide
extensive improvements to Townsville Harbour and the Platypus
Channel, but this was abandoned before completion. Between
1942 and 1945 the 'Cleveland Bay' continued maintenance
dredging as well as developmental dredging for a proposed
naval and lighter wharf. The Queensland Department of
Harbours and Marine's suction dredge 'Morwong' assisted with
maintenance dredging in the Platypus Channel and Outer
Harbour in November and December 1943 and raised 135,000
barge yards of material (Table 2). On 28 March 1944 the port
was affected by a cyclone, resulting in subsequent siltation
problems, but by 11 June 1945 the minimum LWOST depths were
reported as Platypus Channel 22ft, Outer Harbour swing basin
23ft and berths 1-7, 28.5-29ft.
Between September 1945 and March 1948 the 'Cleveland Bay' was
out of commission for major repairs including fitting a new
boiler and bucket ladder. Another cyclone and major flood
occurred in March 1946 and produced considerable silting in
12
the dredged areas. Maintenance dredging was undertaken by
the 'Trinity Bay' and 'Morwong' (Plate 2) in 1946-47 and by
the former in 1947-48 (Annual Reports of the Queensland
Department of Harbours and Marine, 1934-87). The 'MorwOn9'
dumped spoil at sea, prior to completion of the wharf pumping
station at the reclamation site in front of Pilot Hill on 13
September 1946 (Taylor, 1980). The spoil which was
subsequently pumped ashore from the 'Morwong', and in April
1949 on a smaller scale from the 'Trinity Bay', was
subsequently (c.1950) claimed by the Townsville Harbour
Board's Chief Engineer to be unsuitable for reclamation
because of its silt-laden character. (Several years later
the area was filled with sand from the land). After the
'Cleveland Bay' was recommissioned in March 1948 it worked
double shifts of maintenance dredging but experienced
difficulty in maintaining depths in the port.
1951-1960
Taylor (1980), in considering future port development in
the 195U's, stressed the importance of restoring harbour
depths to levels achieved 20 years earlier and forcefully
expressed the opinion that "Dredging operations during the
complete term of the Townsville Harbour Board's
administration of the Harbour, and extending back some twenty
years before that, had been the prime and most expensive
requirement to keep the port in existence. It has been
conclusively proved that the berths of the harbour silt up
froln three to four feet a year in normal weather conditions,
and the siltation of Platypus Channel particularly extending
approximately 5,000 feet seawards from the mouth of the
harbour, is even greater". In 1951 and 1952 the 'Cleveland
Bay' continued to work double shifts carrying out maintenance
dredgin9 in the Platypus Channel and Outer Harbour and
developmental work to deepen the berths. Sand from Ross
River mouth was used in reclamation work near the finger
13
pier. In December 1952 the new suction dredge 'Townsville'
(Plate 3) built in Newcastle, N.S.W. arrived in the port and
joined the 'Cleveland Bay' in dredging work of all types. By
1954 it was claimed that "dredging is no longer a problem to
this port" (Annual Reports of the Queensland Department of
Harbours and Marine, 1934-1987). Maintenance dredging was
undertaken by both dredges, but the 'Cl evel and Bay' was used
mai nly for developmental work. Cyclone' Agnes' affected
Townsville on 6 March 1956 but with the two dredges the
siltation effects in the harbour were soon removed.
Developmental dredging for the new Bulk Sugar Terminal was a
huge task for the 'Cleveland Bay' which worked 3 shifts from
November 1957, and due to its overhaul in 1958, the
Queensland Department of Harbours and Marine bucket dredge
'Platypus II' with two barges 'Dugong' and 'Seal' was loaned
from November 1958 to May 1959. The 'Cleveland Bay' then
resumed 3 shift working so that the terminal was able to
handle its first sugar in June 1959 although it was not fully
completed until December 1962.
1961-1970
During the 1960's maintenance dredging was carried out
mai nly by the I Townsvi 11 e' in the Pl atypus Channel, the
various parts of the Outer Harbour and for shorter periods in
the Inner Harbour. The 'Cleveland Bay' continued
developmental dredging to deepen the Outer Harbour, and
prepare for the proposed tanker berth, whilst the Queensland
Department of Harbours and Marine's clam dredge 'Mourilyan'
dredged the Ross Creek boat harbour in 1964 and 1965 to
provide a basin and berths. Dredging the oil and tanker
berth between March and November 1964 was the final
assignment for the 'Cleveland Bay' (Plate 4). Between 1968
and 1970, 150 acres of industrial land was reclaimed on the
left bank of the Ross River estuary by pumping ashore
14
3,034,000 cu yards of sand from the adjacent intertidal zone.
An 8 inch cutter suction dredge 'John A Stein' was purchased
in 1970 to aid this work (Annual Reports of the Queensland
Department of Harbours and Marine 1934-1987), but
subsequently the 21 inch cutter suction dredge 'Kembla'
(later renamed 'A.C.C.I. ') was hired for this and other work
(Taylor 1980).
Whilst details of dredging have been recorded in the
various sources referred to above, although with limited
quantitative data on amounts dredged, very little information
is available about dump sites. In 1883 material was
deposited close to Magnetic Island and in 1892-93 it was to
be dumped in Cockle 8ay, Magnetic Island. Before the
mid-1960's for an unknown period, dredge spoil was dumped
south of Middle Reef (N. Butterworth, personal communication
1988), but then dumping was transferred to a new site
north-east of the harbour entrance and south-east of Hawkings
Point, Magnetic Island. (This was later defined as the
shallow draft dump site shown on Figure 1).
In addition to dredge spoil dumping, in 1963 following
the serious fire in the Bulk Sugar Terminal 43,000 tons of
burnt sugar had to be disposed of. On 12 June 1963
permission was given by the Queensland Department of Harbours
and Marine in Brisbane to the Townsville Harbour Board to
dump this approximately 20 miles north-east of the harbour
entrance seaward of a line between 19°2'S, 147°13.5'E and
18°55' 5, 147 °E.
In October 1964 a new Australian Naval Chart giving
details of soundings in Cleveland Bay was received by the
Townsville Harbour Board and the Chairman commented that the
depths shown "were vi rtually now the same in Cl evel and Bay as
in 1886" (Taylor,1~80). He believed this refuted claims
being made by various bodies and individuals that the
15
disposal of dredge spoil was having an adverse affect on
coral reef growth along the coast of Magnetic Island. In
June 1965 the Board's Chief Engineer instituted a change in
the calculation of material dredged by the 'Townsville' from
measurements in hopper yards to solid yards. The calculation
was made by working out the specific gravities of silt and
salt water and the vessel's displacement. A draught gauge
was fitted to the dredge to indicate that the maximum
quantity of solids was aboard before proceeding to the
dumping grounds. He reported that "In recent tests the
content of spoil in hoppers had varied between 45% and 10%,
which meant, at times, a lot of water had been carried out to
the dumping grounds" (Taylor, 1980). This must be borne in
mind when considering the data in Table 2. The Townsville
Port Authority holds detailed dredging records from September
1965 to February 1983 for the suction dredge 'Townsville'.
The record sheets show particulars of each dredged load
including source. These records were used for the period
September 1965 to February 1968 to compile the first part of
Table 3. After this, monthly dredging returns were compiled
from these records by the Engineer's Department and these
formed the basis for the latter part of this Table. This
will be examined further later.
1971-1980
On 24 December 1971 Cyclone 'Althea' struck Townsville.
Winds gusted to 122 knots, waves of 5ft height were recorded
in the enclosed harbour and a storm surge of 9.25 ft was
generated. A subsequent survey (Taylor, 1980) revealed that
600,000 tons (600,000 cubic yards according to Townsville
Port Authority) of sediment had been deposited in the
Platypus Channel, which reduced its depth by 4.5 ft. The
S.D. 'Townsville' spent 6 months dredging out this material
early in 1972. Later in 1972 the largest dredging programme
ever undertaken by the Port of Townsville in a short period
16
began with the 'Townsville' starting to dredge a new
'dog-ley' channel to extend the Platypus Channel seaward and
make it suitable for deep draft tankers bringing fuel for the
Greenvale Nickel project. It was dredging in comparatively
soft material, and the spoil was carried to a dump site
relatively nearby between the channel and Cape Cleveland "in
depths greater than 6.1m (20 ft) at low water and in a
quiescent area of the bay away from tidal currents" (Taylor,
1980). (This was later defined as the deep draft dump site
shown on Figure 1). The Queensland Department of Harbours
and Marine trailer suction dredge 'Sir Thomas Hiley' was
contracted to assist the 'Townsville' with the developmental
dredging in the channel and swing basin in 1973, 1974 and
1975. The Townsville Harbour Board's consultants wrote to
the Contractor on 30 August 1974 stating that "the excess
quantity of silting (in the berths) which has occurred in the
period betwen July and October, 1973, has occurred in the
period when the 'Sir Thomas Hiley' was dredging the swing
basin and is attributed to its operation" (Plate 5). The
quantity so deposited was calculated as 31,740 m 3 (Taylor,
1980). This is a continuing problem with the 'Sir Thomas
Hiley' and is attributed to the way this type of dredge
operates (N. Butterworth, personal communi cati on 1988). The
'A.C.C.I.' also played a part in this large dredging
programme, which of necessity had to run simultaneously with
maintenance dredging in all parts of the harbour and approach
channel.
On 15 January 1976 the Department of Harbours and Marlne
granted formal approval to the Townsville Harbour Board,
pursuant to the provisions of Section 86 of the Harbours Act
1955-1972, for the dumping of dredged material in the two
areas in Cleveland Bay (Figure 1). This was "subject to the
condition that the depth north of a line Mount Marlow in line
with Hawkings Point (Magnetic Island) must not be reduced
below 8.2m LWOST." These appear to be the same areas which
17
had been in use by the Townsville Harbour Board since
1960's in the case of the shallow draft dump site and
early 1970's in the case of the deep draft dump site.
co-ordinates of these sites are as follows:
the mid
the
The
Deep draft dump site
Corners of rectangle - NW 19· OB' 09"S 146· 56' 29"E
NE 19· OB' 43"S 146· 57' 28"£
SW 19· 10' 39"S 146· 54' 53"E
SE 19· 11 ' 13"S 146· 55' 51"E
Shallow draft dump site
Corners of rectangle - NW 19· 12' 05"S 146· 53' 01"E
NE 19· 12 ' 22"S 146· 53' 30"E
SW 19· 13' 28"S 146· 52' 07"E
SE 19· 13' 45"S 146· 52' 36"E
In February 1976 heavy rains resulted in large
quantities of silt being deposited in the channel once again.
From 1977 to 19UO developmental dredging in the Ross River
channel was carried out by cutter suction dredges, which
pumped the sediment ashore. In 1979-UO about 400,000m3 of
sand was removed from the bed of Ross River, mainly
immediately upstream from the mouth of Goondi Greek. This
sand was used to fill an 8ha reclamation on the east side of
the Harbour's Eastern breakwater.
19U1-1988
From 1981 to the present (19U8) most dredqinq in the
Port of Townsville has been to maintain depths, although some
developmental dredging continued in the Ross River channel
prior to the fishing fleet being moved from Ross Creek to its
new base on Ross River in 19U3. Subsequently Ross Creek has
been used mainly for pleasure boats whereas Ross River is the
18
base for commercial and industrial craft. Maintenance
dredging of Ross River channel has involved some sidecasting
of material by cutter suction dredge, but most of the
material has been pumped ashore. In addition the Townsville
Port Authority's grab dredge has removed small quantities of
material which has been disposed of mainly in the shallow
draft dump site. Until February 1983 dredging elsewhere in
the port was carried out by the S.D. 'Townsville' on a
regular basis throughout the year. Subsequently however the
Queensland Department of Harbours and Marine 'Sir Thomas
Hiley' has undertaken dredging at the Port of Townsville on a
contract basis for a few weeks each year, usually in two
periods, during the winter months (Plate 6). Details of this
dredging are given in Table 4 and will be examined further
below. All this has been maintenance dredging except for
some developmental dredging of the berths in 1988. In 1986,
the split hopper barge 'Eric Netterfield' was completed for
carrying dredge spoil from the harbour and dumping it at
various disposal and reclamation sites. This design of barge
allows unloading of spoil in shallower depths than is
possible with a bottom door barge.
In 1981, the Environment Protection (Sea Dumping) Act
was passed by the Federal Government. The Minister of State
for the Arts, Sport, the Environment, Tourism and Territories
is empowered under the Act to issue dredging and dumping
permits. A copy of the General Permit, Appendix 1 and Annexes
A and S, issued on 31 May 1988 for the Port of Townsville,
forms Appendix 1 of this report. It:
1) grants a general permit to the Townsville Port Authority
" ... for a period of twelve months to load and to dump up
to 350,000 tonnes of dredge spoil arising from the
dredging of Townsville Harbour and approaches ... "
19
2) grants a general permit to the Townsville Port Authority
" for a period of thirty-six months ... to load and to
dump up to 53,000 tonnes of dredge spoil per annum comprlslng
uncontaminated siltation material and spillage arising from
small scale maintenance dredging in Townsville Harbour and
approaches".
The dump sites relating to each of these permits are
clearly defined (Figure 1). The first permit refers to the
deep draft dump site which has been in use since the early
1970's. The second permit which was subsequently modified
with reference to the area, relates to a site close to and
overlapping with the shallow draft dump site which has been
used since the mid 1960's.
The co-ordinates for these sites are now as follows:
Permit 1 for large scale dredging operation
Corners of 4 sided figure - NW 19 0 08' 09"S 146 0 56' 29"E
NE 19 0 08' 43"S 146 0 57' 28"E
SW 19 0 10' 39"S 146 0 54' 53"E
SE 19 0 II' 13"S 146 0 55' 51"E
Permit 2 for small scale maintenance dredging operation
Corners of 4 sided figure - NW 19 0 12' 48"S 146 0 52' 36"E
NE 19 0 13' 24"S 146 0 53' 36"E
SW 19 0 14' 30"S 146 0 51' 30"E
SE 19 0 15' OO"S 146 0 52' 36"E
Dredged Depths at the Port of Townsville and Earlier Dredging
Records
Recorded dredged depths at the port have been compiled
into Table 1 covering the period 1884 to 1987. As indicated
above, the records up to 1906 were taken at random intervals,
but from 1906 onwards quarterly soundings were taken and the
20
annual June data are shown in the Table. From 1925 onwards
minimum depths only were declared for the safety of shipping.
When considered overall, this table shows the steadily
increased depths to which dredging was taken as the port
developed and ships became larger, but it also reveals how
quickly depths deteriorated when dredging was reduced or
stopped.
Records of amounts of sediment dredged are scanty and
intermittent up to 1965, but Table 2 has been drawn up from
all available sources. The use of different units, the
precise definition of some of which is unknown, results in
comparisons being difficult within this table and between
this and Tables 3 and 4, in which the data are given in
tonnes. (At the end of Table 2, the dredging records are
listed for the 'Sir Thomas Hiley' for the years 1973-4 to
1975-6 when she was contracted to Townsville for several
months annually). The only reference to dump sites before
1965 were those referred to in 1883 and 1893 near Cockle Bay,
Magnetic Island.
Detailed Dredging Records September 1965 to August 1988
As indicated in the above review of the history of
dredging in Cleveland Bay detailed systematic records are
available only for the last 23 years. Table 3 has been
compiled from records of each load dredged by the
S.u. 'Townsville' for the period September 1965 to February
1983. The data are presented as monthly and annual totals
dredged from the Platypus Channel, and the Outer Harbour
swing basin and berths for the whole period, and in addition
from the Ross River channel from 1979-80 to 1982-83. The
'dredging year' is defined as the 12 month period ending on
3U June of each calendar year.
21
After the S.D. 'Townsville' stopped dredging in the port
in February 1983, the T.S.D. 'Sir Thomas Hiley' dredged under
contract for the periods shown in calendar years in Table 4.
The two periods each winter formed part of her assignment
from her base in Brisbane to the port of Weipa, with the
first period being during her northward voyage and the second
during her return southward voyage. After the first period
of dredging it is found necessary to allow suspended sediment
to settle, before a survey can be carried out to determine
the detailed localities and the amounts of further dredging
which may be needed to reach required depths. Although
records of each dredged load are kept it proved impossible to
compile tables showing amounts dredged in different parts of
the harbour, because an individual load was often taken from
more than one part. Table 4 therefore shows only totals for
each period of dredging, plus the total for each calendar
year, together with notes as to where the dredging mainly
took place.
The annual dredging records for the 'Townsville' and the
'Sir Thomas Hiley' in the Port of Townsville are plotted as
graphs in Figure 4. The curve for the total amount dredged
shows a steady rise up to 1971-72, followed by an enormous
peak between then and 1975-76. During this period the
'Townsville' was assisted at times by the 'Sir Thomas Hiley'
in the massive programme of developmental as well as routine
maintenance dredging. The maximum was reached in 1973-74
when 2,112,879 tonnes was dredged, followed by 1,493,017
tonnes in 1974-75. In the late 1970's and up to 1980-81 the
level was close to 600,000 tonnes annually but then fell
sharply to about 350,000 tonnes during the 'Townsville's'
final dredging year. Amounts dredged by the 'Sir Thomas
Hiley' alone from 1983 onwards have varied between about
100,UOO and 260,000 tonnes annually.
22
When the curves for dredging in the different parts of
the port by the 'Townsville' are examined (Figure 4) it is
clear that in most years by far the greatest amount was
dredged from the Platypus Channel followed by a much smaller
amount from the swing basin and even less from the berths.
Only between 1975-76 and 1977-78 and in 1980-81 did the
'Townsville' dredge more from the swing basin than the
Platypus Channel (and in 1975-76 the 'Sir Thomas Hiley' was
also dredging in the port).
The monthly dredging records for the 'Townsville' from
September 1965 to February 1983 are plotted in Figure 5. The
gaps in the curve are periods when the dredge was being
overhauled and repaired. Between 1965 and 1971 monthly
dredged quantities were generally between about 10,500 and
30,500 tonnes. During the first half of 1972 the figure rose
to over 60,000 tonnes following Cyclone 'Althea' in late
December 1971. During the massive developmental and
maintenance dredging operation between late 1972 and 1975-76
monthly figures varied widely, with the peak over 118,000
tonnes in October 1972. During the late 1970's and early
1980's when mainly maintenance dredging took place with some
developmental dredging in Ross River channel, monthly
dredging totals varied moderately mainly between 30,000 and
7U,UOO tonnes, with the only marked exception being about
96,000 tonnes in July 1980.
Although no written records could be found relating to the
dumping of dredge spoil between 1965 and 1988, except when
formal approval was granted on 15 January 1976 and permits
were issued on 31 May 1988, it is understood from the
Townsvi 11 e Port Authori ty Engi neer' s Department that all the
material dredged by the S.D.'Townsville' was dumped in the
shallow draft site (Figure 1) which had been in use since the
23
mid 1960's. However, Taylor (1980) states that the sediment
dredged to cut the 'dog-leg' Sea Channel by the S.D.
'Townsville', beginning in late 1972 and later assisted by
the T.S.D. 'Sir Thomas Hiley', was dumped in the deep draft
dump site. The 'Sir Thomas Hiley' has continued to use this
latter site subsequently.
The type of sediment dredged was visually inspected on
the dredge and described on the record sheets, but was not
regularly analysed to provide a more precise sedimentological
description. From the general descriptions it appears that
maintenance dredging from any part of the harbour and channel
yields mainly 'silt' and 'mud'. Developmental dredging,
especially within the harbour, yields harder 'sandstone' and
'stiff clay' in places, but the dog-leg extension to the
Platypus Channel was cut in 'relatively soft material'.
Footnote
An inspection by the British Admiralty Hydrographic
Department of editions back to 1886 of the Admiralty
Hydrographic Chart No.1102 'Cleveland Bay' (which
subsequently became Australian Naval Chart ADS 256) revealed
no information about dump sites for dredged material. As far
as they could ascertain the first edition of ADS 256 to show
such a site was printed in July 1988, but this shows only the
deep draft, large scale dump site (Figure 1).
24
CHAPTER 2
Coastal and Nearshore Zone Changes in the Cleveland Bay Area
Dredging, by removing sediment from one locality and
dumping it in another, not only influences these two
localities, but may also affect other areas of the seabed and
neighbouring coasts to which the dumped sediment may be
carried subsequently by wind, wave and tidal processes. A
series of aerial photographs can provide a valuable record of
coastal change and, under clear water conditions, of changes
in the nearshore zone. These changes may be entirely natural
or may be influenced by man to some degree where engineering
structures are built and dredging takes place. Vertical
aerial photographs of the Cleveland Bay area spanning the
last 47 years, from 1941 to 1988 (Table 5) have been analysed
to determine the type and amount of coastal and nearshore
changes. These will be considered in detail in this chapter,
plus an assessment of changes shown by a limited number of
ground surveys. Subsequently the natural processes and man
induced effects will be assessed in an attempt to determine
the causes of the changes.
The aerial surveys listed in Table 5 were selected to
span as long a period, and to give as regular a time interval
between surveys, as possible. Because of the small number of
aerial surveys undertaken in the 1940's, 1950's and 1960's
the time interval was at its longest 17 years. Many more
aerial surveys have been flown in the 1970's and 1980's,
therefore the time interval has been reduced to 3-4 years
generally for this period. The surveys selected were also
those which gave an extensive cover of the Cleveland Bay
area, at a small enough scale to show detailed coastal and
nearshore features. Photographs at a scale of about 1:12,000
are particularly valuable and as six of the surveys were at
this scale they could be compared directly. All the aerial
25
surveys chosen from 1974 onwards used colour film and this
provides a considerable advantage over black and white when
detailed variations in sediment and vegetation are being
studied. However after analysing colour aerial photographs
it is relatively easy to analyse black and white photographs
of the same area and similar range of phenomena.
The coasts of Cleveland Bay and the adjacent nearshore
areas will be examined in an anticlockwise sequence from
Shelly Beach - Cape Pallarenda to Cape Cleveland. A similar
anticlockwise sequence around Magnetic Island will begin at
West Point (Figure 1).
Shelly Beach - Cape Pallarenda
The best exposure of the intertidal and subtidal zones
as well as the coastline itself is shown on the aerial
surveys of 1-7 June 1959, 30 May 1974, 14 July 1981 and 15
June 1985 (Figure 6). The rock coast of Cape Pallarenda is
cut in granite and volcanic agglomerates and two sand beaches
have formed within an embayment and west of the rock
outcrops. Shelly Beach is backed by a 3km long vegetated
sand bar/spit which formed from east to west as indicated by
the alignment of its lateral ridges. It may have originated
as a nearshore bar which was driven landward by wave washover
processes as it extended westwards, in a similar manner to
the east Burdekin delta spits and bars (Pringle, 1983 and
1984). Streams from the higher ground inland flow into
Shelly Creek which lies along the landward side of the
bar/spit and has mouths at both its east and west ends.
Throughout its length Shelly Creek is flanked by mangroves
which reach the coast near its mouths. An extensive
intertidal and subtidal foreland has developed northwards
from the Shelly Beach - Cape Pallarenda coast and has been
shaped by sediment supply and wave and tidal processes acting
from both east and west.
26
The major change along the coast, revealed by these
aerial photographs, is to the sand beach east of the east
mouth of Shelly Creek. During the period 1959-19US this
beach was driven shorewards into the mangroves on its
landward side. Some of these, now on the seaward side, have
died as their roots are exposed by wave erosion.
Comparing the intertidal and subtidal foreland on the
different surveys is complicated, firstly by the varying
photographic cover of this area (this locality lies at the
end of tne Beach Protection Authority's St. Lawrence -
Townsville coastal segment for aerial surveys) and secondly
by the different tidal heights. Overall, the position and
form of the major sand banks were similar on the four
surveys. The main sediment source appears to lie in the west
mouth of Shelly Creek and the mouths of the Bohle and
possibly Black Rivers further west. This sediment is
transported north-eastwards by wave and possibly tidal
current action and is formed into major sand bars aligned
south-west to north-east. A much smaller amount of sediment
appears to be carried westwards around Cape Pallarenda to
form curved sand banks close to the coast in the north-facing
embayment and possibly feeding sand bars lying parallel to
the coast further west. The eastward side of the foreland is
not continuous as a deeper water area lies north of these
smaller sandbanks. North of tnis, towards the apex of the
foreland, the major sand bars swing round northward from
their south-west to north-east alignment. This effect and the
deeper water area are probably produced by strong tidal and
wind-induced currents and possibly wave action within the
narrow confines of West Channel between the mainland and the
south-west coast of Magnetic Island.
Areas of seagrass were clearly visible in the central
and coastward sections of the foreland on the 1959, 1981 and
27
1985 aerial photographs. However none showed on the 1974
photographs despite their high quality and the water clarity
which enabled the sand banks to be mapped easily.
Cape Pallarenda to Ross Creek
This section is clearly shown on most of the aerial
surveys {Figure 7}. A narrow upper beach of relatively
coarse sand adjoins the sand dunes in Rowes Bay and below
this, exposed at L.W., are a series of irregular sand bars
and troughs, generally arranged parallel to the coast. There
are only two exceptions to this pattern. At the mouth of
Three Mile Creek an intertidal to subtidal delta has formed
which is symmetrical in plan view, but which has the best
developed sand bars directly seaward and to the north of the
mouth. In the inner part of Rowes Bay adjacent to the
granite headland of Kissing Point the intertidal zone widens.
Only a very narrow sand beach exists flanked by fine sand and
mud seaward, in which mangroves are colonizing. Towards LWM
a series of oblique sand bars have formed. Between Kissing
Point and Ross Creek mouth the coast flanking The Strand in
Townsville is artificially protected with large boulders.
Only a narrow sand beach is present here and its volume
becomes less towards Ross Creek. Before the Harbour was
constructed this beach would have received sediment from Ross
Creek and Ross River, but the Harbour now blocks that, in
acting like a giant groyne.
Changes along this coast have been slight between 1942
and 1988, as shown on the aerial photographs. The delta at
Three Mile Creek mouth has remained similar in size and form;
the features characterising the inner part of Rowes Bay show
little change except for a slight extension of the mangroves;
and between Kissing Point and Ross Creek the major change has
been man-made with the formation of the marina and
reclamation for the hotel and casino adjacent to the Eastern
Breakwater of the Harbour.
28
Ross River to Sandfly Creek
The aerial surveys which best show not only this section
of coastline but also the intertidal zone are those of 1-7
June 1959, 14 June 1974, 14 July 1981 and 15 July 1985
(Figure 8). Ross River, its tributary Stuart Creek and
Stuart Creek's distributaries, Sandfly Creek and the smaller
creek westwards, have ~rovided the main source of terrigenous
sediment input to Cleveland Bay until the building of Ross
River Dam in 1973. The coastline is composed of sand ridges
with areas of mangroves commonly both seaward and landward.
The intertidal zone clearly shows that Ross River carried the
largest sediment load which was initially deposited in an
intertidal and subtidal delta with its apex eastwards of the
river mouth, reflecting the eastward curve of the main
channel. Smaller sediment loads were deposited by Sand fly
Creek and the western distributary and this extended the
delta eastwards, in a series of sandbanks.
Changes to this coastline between 1941 and 1973 were
examined in detail by comparing aerial photographs taken in
1941, 1952, 1959, 1961, 1965, 1971/72 and 1973 (McIntyre and
Associates, 1974). Erosion was most pronounced near the
mouths of Ross River and Sandfly Creek (Figure 9), especially
during the inter-survey periods 1952-1959 and 1965-1971/2 and
is attributed to cyclones in 1956 and 1971. Progradation of
sand ridges in the Ross River mouth area and mangroves and
sand ridges near the mouth of Sandfly Creek partially
counterbalanced the erosion. Changes were less marked along
the central section of this coast, where progradation by
mangroves was dominant overall.
Whilst knowledge of this type and scale of coastal
change is important in understanding the evolution of a
particular coastline, it was felt that in the current
29
project, where the possible effects of dredging are of major
concern, a broader examination of both coastline and
intertidal zone was more appropriate.
The map drawn from the 1959 aerial photographs (Figure
8) shows the Ross River mouth in a natural state except for
the influence of the Harbour's Eastern Breakwater. The main
channel curved eastwards from the mouth, but more minor
channels were cut slightly to the west through sandbanks in
which the river's load was initially deposited. The 1974
aerial photographs were taken at a higher state of the tide
with the channels and banks therefore less exposed; a
channel can be seen directly seaward of the mouth, but a
major one eastwards is only hinted at. (The 1973 photographs
show both channels more clearly). The major reclamation of
land on the west shore of the mouth between 1968 and 1970 had
- - --
involved the pumping ashore of 3,034,000 cu yards of sand
from the adjacent i nterti dal sandbaiiks and-thi s probably
r~ulted in the development~ ~ larger channel directly
seaward of the mouth. By 1981 the ma in channel lay in thi s
position, with the only evidence of the former eastward
swinging one being in the position of the apex of the
intertidal/subtidal delta. This change was strongly
influenced by developmental dredging of the Ross River
channel from 1977 into the early 1980's. Between 1981 and
1985 an angled harbour wall was constructed east of the
- - -- -
Eastern Breakwater across part of the inter-tidal sandbanks
on the west side of RossRiver mouth-.-Changes wlTT clearly
result within the semi-enclose~area, but the main channel
\
ly~~a!allel to its eastern side has not changed position
during this period. The minor channel lea ing westwards from
it has diminished as sandbanks have grown west of the main
channel. The apex of the delta in 1985 and in 1988 still
shows the former dominance of the eastward curving main
channel.
30
The intertidal zone beyond the mouth of Sandfly Creek
and the western distributary has shown no major changes
between 1959 and 19H5. In each case the channel has curved
westwards from the mouth and has contributed sand to the
intertidal/subtidal delta and its eastward extension. The
sandbanks between the two channels lie oblique to the
coastline, being nearer to it at their western ends.
Along the coastline mangroves have become almost
continuous, seaward of a vegetated sand ridge, during this
period. Only immediately east of Ross River are they absent,
with the sand ridge flanking the coast.
Sandfly Creek to Cocoa Creek
The aerial surveys of 11 August 1961, 9 October 1973, 30
May 1974, 28 November 1978, 14 July 1981 and 24 June/15 July
1985 provide the clearest views of this coast and the
adjacent intertidal zone (Figure 10). This is a lower energy
coast than that further west in Cleveland 8ay, owing to the
sheltering effect of Cape Cleveland. Three main creeks enter
the bay along this coast, from west to east, Alligator,
Crocodile and Cocoa Creeks. Elsewhere the coast is flanked
almost continuously by mangroves and the adjacent intertidal
zone is of mud or fine sand.
Changes along the coastline were examined by comparlng
aerial photographs taken in 1941, 1959 and 1973 (McIntyre and
Associates, 1974)(Figure 11). The most pronounced erosion
occurred between 1941 and 1959 along the mangrove coast
between Sandfly and Alligator Creeks where a recession of 50m
occurred, and along the west banks of the mouths of
Alligator, Crocodile and Cocoa Creeks where about 30m was
removed. Elsewhere between 1941 and 1973 mangrove
colonization produced coastal progradation, of about 20m
south of Sandfly Creek and east and west of Alligator Creek.
31
Examination of this coastline on the 1974, 1978, 1981
and 1985 aerial photographs revealed no change in the extent
of the mangrove belt and little change in the channels and
sandbanks in the intertidal zone seaward of the creek mouths.
Elsewhere the intertidal zone of fine sediment was traversed
by a network of very small drainage lines only. Between
Sandfly Creek and the west side of Crocodile Creek no
seagrass was visible on the 1974, 1978 and 1981 photographs.
It was identified, however, on the 1985 survey near and
seaward of LWM, between a point midway between Sandfly and
Alligator Creeks and the west side of Crocodile Creek.
Between Crocodile Creek and Cocoa Creek its extent varied on
the different surveys:
1974 No seagrass was visible along this coast.
1978 Seagrass below LWM was visible immediately west of
Crocodile Creek channel and north-eastwards from there
parall el to the coast.
1981 Seagrass above and below LWM extended from immediately
west of Crocodile Creek channel north-eastwards parallel
to the coast.
1985 Seagrass below LWM extended parallel to the whole
section of coast and appeared relatively dense east and
west of the Cocoa Creek channel.
Cocoa Creek to Cape Cleveland
The aerial surveys of 11 August 1961, 9 October 1973, 30
May 1974, 28 November 1978, 15 July 1981 and 24 June 1985
provide the best cover of this coast for the present study.
Along the west side of the granite promontory of Cape
Cleveland, with volcanic rocks forming its tip, rocky coasts
and small headlands are interspersed with small bayhead sand
beaches with mangroves in places (Figure 10).
32
Comparison between 1959 and 1973 aerial surveys
(McIntyre and Associates, 1974) showed these beaches to be
relatively stable in comparison with other Cleveland Bay
beaches. The changes which were noted had no clear pattern.
The beach near the lighthouse receded about 4m whereas the
next bay south, Red Rock Bay advanced by a similar amount.
Long Beach was relatively stable except near the creek mouth
where the shore prograded by 3m as also did the beach in
White Rock Bay. The sandy part of Laun's Beach remained
stable. The mangroves occurring at intervals along this
section of coast, were also stable generally but with a small
advance taking place where silt had accummulated at the
southern end of each patch. A mangrove advance of 20m
occurred on Long Beach, 25m on Laun's Beach and about 10m
north of Cocoa Creek, south of the most southerly rock
outcrop of Cape Cleveland.
In the present study, examination of the 1974, 1978,
19til and 198b aerial photographs showed no clear change to
the sand beaches along this section of coast and only small
changes along two parts of the mangrove fringed coast. At
the north-east end of Laun's Beach, the mangroves extended a
short distance along the coast towards the rock outcrop
between 1974 and 19t1~; and mangrove colonisation began on
the north-east side of White Rock Bay. The extent of the
seagrass varied on the different surveys, as was the case
further west between Sandfly and Cocoa Creeks:
1961 Sea grass was visible below LWM seaward of the north-east
end of Laun's Beach and Long Beach.
1973 No seagrass was visible above or below LWM.
1974 Seagrass was visible only below LWM immediately east of
Cocoa Creek channel. From Cape Cleveland south to Long
Beach the water was very turbid with large southward
pointing plumes of sediment in suspension.
197tl Seagrass was visible below LWM north-east of Cocoa Creek
in two bands parallel to the coast, with a strip of
sediment between. Along the rocky coast, seagrass was
visible below LWM only intermittently due to highlights
on the photographs where the sun was reflected from the
sea surface,
33
1981 North-east of Cocoa Creek seagrass was visible above and
below LWM in the troughs between oblique bars of
sediment (the south end of the bars, lying closest to
the coast). There was thicker, more continuous seagrass
seaward. Along the rocky coast, a large area of
seagrass was visible above and below LWM extending from
the first rock headland south of Cape Cleveland to Long
Beach.
1985 North-east of Cocoa Creek seagrass was visible again in
troughs between oblique sediment ridges, and opposite
the first rock headland north of Laun's Beach, in
troughs between sediment ridges parallel to the coast.
Northwards to the first rock headland south of Cape
Cleveland seagrass was visible below LWM, in patches
interspersed with sediment nearer the coast, but with
denser growth seawards.
Magnetic Island, South-West Coast
The aerial surveys of 1-7 June 1959, 11 August 1961, 30
May 1974, 28 November 1978, 14 July 1981 and 15 June 1985
give a good overall view of this coast and the intertidal
zone. The coasts of Magnetic Island have a distinct feature
not found on the mainland coast of Cleveland Bay, namely
fringing coral reefs. Because the south-west coast is the
most sheltered, coral reef growth has been most extensive
here, probably since Holocene time, and an extensive reef
flat with overlying sediment extends seaward into West
Channel from near Nobby Head to the south side of Bolger Bay,
(Figures 12 and 13). Apart from rocky shores near Nobby Head
and West Point, the remainder of this coast is depositional,
with sand beaches south of West Point, between Young and
Bolger Bays and in Cockle Bay, and with mangroves fringing
the remainder.
The rocky shores and sand beaches show little change on
this sequence of aerial surveys from 1959 to 1985, and the
seaward margin of the mangroves is similar throughout.
However whereas a dense continuous strip of mangroves is
shown on the 1959 and 1961 photographs, extending landwards
to salt flats or higher ground, marked destruction had
34
occurred by 1974 in a broad strip landward of the seaward
fringe. This destruction was most marked in the mangroves
between Bolger and Cockle Bays, although it had occurred to a
lesser extent in the Young Bay mangroves. The zone of dead
mangroves continued to be a prominent feature in 1978, but by
1981 regrowth was turning the strip into patches and those
patches had diminished further by the 1985 survey.
The coral reef flat is the most dominant feature of the
intertidal zone along the southern half of this coast, with
fine-sand and mud in this zone northwards off Bolger and
Young Bays. In 1959 patches of seagrass and sediment were
visible under water extending between these two bays.
Further south areas of seagrass were growing in the channels
near the landward side of the coral reef flat north-west of
Cockle Bay and seaward, interspersed with sediment, on the
reef flat off Bolger Bay. Patches of seagrass and sediment
were visible also in a belt off Cockle Bay and extending
along the shore to near Nobby Head. This seagrass
distribution pattern was broadly similar in 1961, but in 1974
no seagrass appeared, despite clear under-water visibility on
the aerial photographs. In 1978 a small area was visible in
the channel landward of the reef flat south of Bolger Bay.
more extensive areas were seen under-water off Young Bay and
there were possibly small patches interspersed with sediment
south-east of Cockle Bay. The 1981 aerial survey showed
dense seagrass growing in the channel landward of the reef
flat south of Bolger Bay and seagrass patches growing
extensively in the sediment on the reef flat seawards. Dense
seagrass was also seen growing under-water off the north end
of the reef, seaward of Bolger Bay. The 1985 aerial
photographs show dense seagrass patches in the channel
landward of the reef, north-west of Cockle Bay and on the
northern end of the reef flat. Seagrass interspersed with
sediment is also extensive on the reef flat north-west of the
water pipeline which was installed between 1981-1985 (a
35
marked contrast existed between the two sides of the
pipeline, with no seagrass identifiable to the south-east}.
Some seagrass was growing above LWM in the fine sediment
seaward of Young and Bolger Bays.
Whilst much of the coral reef flat is dead with sediment
on it, and seagrass in places, bare coral was visible in all
the aerial surveys, off Cockle Bay, in the channel which
separates the landward area of reef flat from the oval area
seaward.
Magnetic Island, South-East Coast
The aerial surveys of 1-7 June 1959, 11 August 1961, 30
May 1974, 28 November 1978, 14 July 1981, 28 June 1985 and 30
June 1988 give good coverage of this coast and intertidal
zone. The coast consists of a series of granite promontories
separated by bays, which are only small along the northern
half, but are much broader further south (Figure 12). In the
major Picnic, Nelly and Geoffrey Bays large coral reefs have
formed in the shelter of rock headlands to the north-east,
with smaller reefs forming in similar positions in Alma,
Arthur, Florence and Gowrie bays further north. In all
except the last of these bays and in Rocky Bay sand bayhead
beaches have formed.
From these aerial photographs at a scale of about
1:12,000 or more the sand beaches in the small bays show
little change in width or bayhead position throughout the
period 1959 to 1988. Similarly the coral reefs in the small
Alma, Arther, Florence and Gowrie Bays, which are seen
beneath the water on most of these surveys, show little
detectable change in extent.
The three major bays have several characteristics in
common and show a little variation between surveys. Picnic
36
Bay has a continuous upper beach of relatively coarse sand
and is flanked by a lower beach of finer sand which reaches
its broadest at the north-east corner of the bay. The fine
sand covers the upper part of the coral reef flat. Seaward
the reef flat with living coral is extensively exposed at
LWST. The extent to which the reef flat was bare of sediment
varied on different surveys. The lower beach was less
extensive in 1974 than in 1959; it was more extensive west
of the jetty in 1978 than in 1974; it was less extensive
east of the jetty in 1981 than in 1978; but subsequently in
1985 and 1988 it showed little variation with 1981. A
separate coral reef lies seaward and curves round Nobby Head.
Nelly Bay shows a similar distribution of upper and
lower sand beaches to Picnic Bay, but towards the seaward
side of the lower beach, sand bars are usually well
developed, extending from the granite headland to the
north-east towards the centre of the long upper beach.
However the extent of sand bar formation showed some
variation between surveys. There were less sand bars in 1974
than in 1959; they were better developed in 1978 than in
1974; they were less developed and smaller in 1981 than in
1978; there was little change in 1985, but in 1988 a very
well developed large sand bar extended almost completely
across the north-eastern end of the bay from close to the
rock headland. Nelly Bay has an extensive coral reef seaward
and south-west of the lower sand beach.
Geoffrey Bay has upper and lower beaches and a coral
reef similarly distributed to those in Picnic and Nelly Bays.
As in Nelly Bay sand bars develop along the seaward edge of
the fine sand lower beach, from midway along the rock
headland at the north-east end of the bay to about two-thirds
of the distance south-westwards along the narrow upper beach.
There were less variations on the lower beach in Geoffrey Bay
than in Nelly Bay during the period of aerial surveys.
37
Little change occurred between the 1959 and 1981 surveys,
then in 1985 the lower beach had extended towards the quay on
the headland, but had moved away from it again by 1988.
Magnetic Island, North Coast
The aerial surveys of 1-7 June 1959, 11 August 1961, 30
May 1974, 28 November 1978, 14 July 1981 and 15 June 1985
provide the most complete cover of this coast. For most of
its length this is a rocky coast mainly formed in granite,
but with volcanic rocks outcropping near West Point (Figure
12). Bayhead beaches of relatively coarse sand have formed
in the small bays: Radical, Balding, Maud, Norris, Wilson
and Huntingfield Bays. Small coral reefs have developed
seaward of the sand beaches in Maud and Wilson Bays which are
well sheltered by rock headlands on their western sides.
Horseshoe Bay is the only major bay along this coast. It has
a long sand bayhead beach and coral reefs have formed in two
sheltered embayments along the rock headland bounding its
eastern side. A sand beach flanks the landward side of the
northerly reef.
No pronounced changes could be detected in the small
bays, either to the sand beaches or coral reefs, from the
aerial surveys. In Horseshoe Bay, the sand beach varied
little in width or length between 1959 and 1985. George
Creek, which was diverted towards the eastern end of the
beach in 1959 and 1961, had cut a more direct route seaward
nearer the western end by 1974; then between 1981 and 1985
it became increasingly direct. The coral reefs and beach
landward of the northern one changed little during the whole
period, but there was a slight variation in the extent to
which sand delivered by a small creek, covered the south end
of the southern reef.
38
Ground Surveys
From the aerial surveys, changes in plan view have been
mapped, described and discussed for the period 1941 to 1988.
In comparison with the aerial surveys, coastal ground surveys
have been much more limited in scope and frequency.
The most extensive ground surveys were carried out by
the Beach Protection Authority in 1982 and 1983 along the
west Cleveland Bay coast between Townsville Harbour and Cape
Pallarenda, and on Magnetic Island between Picnic and Alma
Bays on the south-east coast and between Radical and
Horseshoe Bays on the north coast (Figure 14). 1/6 of the
approximately 2,OOOm long cross profiles were surveyed only
once, but the remaining 45 were surveyed in both years.
Overall the vertical changes along these were slight and are
summarized in Table 6. (As these survey results were
obtained as plotted profiles amounts of change cannot be
ascertained precisely).
Other coastal ground surveys were carried out by the
Townsville Port Authority along 5 cross profile lines between
Townsville Harbour and Cape Pallarenda (Figure 10).
Replicate surveys were undertaken on 6 dates between 26
January 1978 and 28 March 1983 and a summary of the changes
between successive surveys is given in Table 7. As with the
Beach Protection Authority surveys, overall the vertical
changes along the profiles were only slight (ie 0.1 - 0.2m
accretion or erosion). The most consistent changes were in
the sand bars and troughs along the landward 850m of the Run
4 profile in Rowes Bay. (Since this data was collected and
analyzed a further survey was undertaken along 4 of the above
cross profile lines on 7 December 1988).
39
CHAPTER 3
Processes Influencing Sediment Movement in Cleveland Bay
In order to assess any possible role which dredging has
played in the coastal and nearshore zone changes revealed by
the aerial surveys between 1941 and 1988 and the ground
surveys of the late 1970's to early 198U's, it is necessary
to review the processes influencing sediment movement in
Cleveland Bay. Processes operating in the coastal catchments
as well as marine processes are important.
A Coastal Catchment Processes
Cleveland Bay is influenced not only by the catchments
of the small rivers flowing into it, of which the Ross River
2 2(catchment area 750 km ) and Alligator Creek (69 km ) are the
largest, but also the vast 129,660 km 2 catchment of the
Burdekin River, the delta of which lies south of Cleveland
Bay(Figure 22). For both geological and climatic reasons
ideal conditions exist for. a high sediment yield.
1 Geology
Geologically, there are remnants of sedimentary basins
containing Palaeozoic flysch sediments, inter-bedded with
thick silica-rich volcanic flows and tuffs. Granitoid
plutons were densely intruded probably during the Upper
Carboniferous and basin outlines were changed later by
igneous intrusions, faulting, folding, erosion and
concealment by younger sediments. More recently during the
Tertiary and Pleistocene large areas were covered by olivine
basalts and surficial deposits of unconsolidated sands,
gr avel s, clay san d silt s .
40
2 Climate
The seasonally wet and dry tropical climate, with
rainfall occurring primarily during the hotter summer months
between November and April, when tropical cyclones may occur
and generate major river floods, produces rapid weathering
and erosion. Rainfall records for Townsville Pilot Station
(1871-1940) and Townsville Airport (1941-) have been
amalgamated to produce Table 8, which is presented in
hydrological years commencing in October. The mean annual
rainfall is 1147mm and the monthly means show a clear
concentration between December and March, but with moderate
rainfall in November and April. Table 8 and Figure 16 reveal
a further characteristic of the rainfall, its marked
variability from year to year, ranging between a minimum
yearly total of 236mm in 1901-2, to a maximum of 2661mm in
1889-90. The highest rainfall totals, as well as the highest
intensity rainfall, are usually related to a tropical cyclone
nearby.
3 River Regimes
The river regimes strongly reflect the rainfall pattern.
Records of monthly volumes for Ross River at the Ross River
Dam headwater (1974-1987) (Table 9a), Alligator Creek at
Allendale (1974-1987) (Table 9b), and Black River at the
Bruce Highway, slightly north of Cleveland Bay (1973-1987)
(Table 9c) show maximum discharge between December and May.
Low flows occur between June and November in Alligator Creek
and Black River during the winter dry season, but on Ross
River, dammed since 1973 no water passes over the spillway
during most of this season. These are the only rivers
flowing into Cleveland Bay or nearby for which Queensland
Water Resources Commission (QWRC) records exist for more than
2 years. The high annual rainfall variability is clearly
reflected in the variations in the annual volume figures for
41
these three rivers: Ross River 302,672 - 0 Ml, Alligator
Creek 66,932 - 6,327 Ml & Black River 399,051 - 55 Ml, and
seasonal variations are shown in the monthly volume figures:
for Ross River 191,089 - 0 Ml, for Alligator Creek 33.226 - 0
Ml, and for Black River 186.358 - 0 Ml.
For the much larger Burdekin River south of Cleveland
Bay, longer discharge records exist, taken at Home Hill
(1920-57) and at Clare (1949-). The Burdekin dominates
coastal discharge over a wide area. including Cleveland Bay.
with a mean annual discharge of 11.027,855 Ml and a range
between 54,066.314 Ml and 305.185 Ml (QWRC data for Clare
1985). Analysis of Burdekin data for the period 1940 to 1980
has identified the major floods, and the close link between
them and the passage nearby of a tropical cyclone is clearly
shown in Table 10 (after Pringle, 1986). No further cyclones
affected this coast between 1981 and 1987.
4 Sediment Supply to the Coast
The seasonality and high variability of rainfall from
year to year is reflected through the river regimes in the
rate of sediment supply to the coast. Whilst few
measurements of sediment load have been taken along
north-east Queensland rivers. some theoretical calculations
have been made (Pringle, 1986). Belperio (1979) calculated
the sediment and solute loads of the Burdekin River as
follows in million tonnes:
Washload Bedload Dissolved Total
Load
Average year 3.00 0.45 0.90 4.35
Flood year 1957-8 19.70 3. 70 2.40 25.80
Drought year 1968-9 0.008 0.001 0.080 0.089
24h of peak discharge
March 1946 (39,600cumecs) 6.40 1. 70 0.30 8.40
42
For the Ross River (Belperio, 1983) has estimated the total
mean annual load as 0.33 million tonnes but proportionate
fluctuations will occur. The presence of the Ross River Dam
since 1973 will have profoundly affected sediment delivery
into Cleveland Bay, with the coarse fraction being trapped in
the reservoir under most, if not all, conditions of flow.
5 Pollution
In addition to natural inputs of water and sediment from
the rivers to the coast (even if these are distorted by
engineering works upstream) man may be responsible for
chemical and biological inputs through discharge of sewage
and industrial effluent. Up to 1940 septic tanks were used
in the Townsville area, but then after the installation of a
mains sewage system, raw sewage began to be discharged into
Cleveland Bay (G. Jones, Townsville & Thuringowa Water Board,
personal communication 1988). Initially this was through a
pipe at the Ross River mouth, directly into the inter-tidal
zone (Figure 1). In 1986 this pipe was sealed and sewage was
diverted to Sandfly Creek to double the existing level of
effluent in that Creek. The Sandfly Creek sewage plant was
commissioned in 1963, but not completed until 1976 therefore
there was a gradual increase in effluent from 1963 to 1976.
A secondary treatment plant was installed and became
operational in 1989. Improvements are planned for the
treatment of sludge from the plant. A further sewage
treatment plant is in operation and discharges into lagoons
near the Bohle River mouth. For the relatively isolated
settlements on part of Magnetic Island and elsewhere in the
Cleveland Bay area, package sewage treatment plants are
installed and the effluent is used for irrigation water. The
remainder of Magnetic Island is on septic systems.
43
Responsibility for monitoring and analysis of water
quality lies with the Queensland Water Quality Council,
recently renamed the Queensland Department of Environment and
Conservation, Division of Environment. To determine the
extent of influence of existing disharges to Cleveland Bay,
water and sediment sampling exercises were undertaken between
1980 and 1982 and the results submitted in a report to the
98th Meeting of the Council (31 March 1982) and in a
subsequent addendum (undated, c1983). Results of the
sediment analyses are of relevance to the present project.
Sediment Pollution Study
Sediment sampling sites were located near the Ross River
(eastern suburbs) and Sandfly Creek outfalls and seaward of
these in an attempt to completely cover the zone of influence
of the discharges (Figure 17a).
a) Sediment grain size
Sediment grain size analysis showed that >85% of most
samples was <O.6mm (ie finer than coarse sand on the
Wentworth scale). As settlement of particle-associated
pollutants takes place mainly on sediment <O.063mm (finer
than sand) the proportion of these fines in the samples was
examined (Figure 17b). High levels were found in the
mangrove fringe near HWM, lower levels in the higher energy
mid to lower intertidal zone, then increasing levels seaward
of LWM. Superimposed on this general pattern is an area of
high levels seaward of the Ross River mouth, which may be
part of the settling zone for fine particles discharged by
the river and possibly also by Sandfly Creek.
44
b) Escherichia coli
The detection limit for E. coli was 10 2 colonies/gm of
sediment and at most sites levels were lower (Figure 17c).
However, positive results were obtained near the outfalls and
in a zone northwards; and the shoreline and intertidal zones
between the outfalls, together with Ross River were shown to
be extensively contaminated.
c) Coprostanol
Coprostanol, found in the faeces of humans and other
higher species is another useful indicator of sewage
contamination, and persists longer than E. coli. Positive
values were grouped round the outfalls, but also extended
northwards from Ross River and Sandfly Creek mouths and
linked seaward (Figure 17d). Two separate zones north-east
of Sandfly Creek may reflect the movement of a plume in that
direction under certain wave and tidal conditions.
d) Phosphorus
Total phosphorus shows a similar distribution pattern to
that of sediment <0.063mm, as it is readily adsorbed onto
fine particles (Figure 17e). As levels were low near the
outfalls little enrichment occurred from the discharges.
e) Bicarbonate Extractable Phosphorus (BEP)
Only at sites close to the outfalls were levels raised
(Figure 17f). B.E.P. is regarded as an acceptable relative
measure of biologically available phosphorus and these
results suggest there has been little increase in the
eutrophication potential due to this factor.
45
f) Acid Extractable Phosphorus (AEP)
This has a completely different distribution pattern to
those of the other phosphorus fractions (Figure 17g), but
showed similarities with the E. coli and coprostanol
patterns. Marked contamination occurred around each outfall
and extended along the shoreline and intertidal zone between
them. It also extended seawards north of Ross River mouth to
the edge of the sampling grid (and therefore maybe beyond it)
and northwards from Sandfly Creek.
g) Oil and Grease
Values were generally low over the sampling grid area,
implying low contamination levels (Figure 17h). The higher
values in Ross Creek mouth were believed to have a source
other than sewage effluent.
h) E. coli, coprostanol and acid extractable phosphorus
Finally the distribution patterns of these three
indicators of sewage contamination were combined
(Figure 17i). Areas of greatest contamination lay around the
two outfalls and the adjacent shoreline and inter-tidal zone,
with a further area seaward of Ross River mouth. It is
suggested that the latter is the zone where pollutant
particles from both effluent plumes settle out in an area of
predominantly fine sediment. A continuous area of lower
pollution existed around the more highly polluted cores.
Overall however it was concluded that the sewage effluent was
making a relatively minor environmental impact because of the
high degree of dilution and dispersion in Cleveland Bay. The
only serious exception was in Sandfly Creek which was grossly
polluted.
46
Since this report was completed about 1983, the closure
of the eastern outfall in 1986 and diversion of its effluent
through Sandfly Creek is likely to have changed the pollution
pattern and levels considerably. However, the secondary
treatment plant which recently became operational in 1989
should improve the situation rapidly.
B Marine Processes
1 Wind Influences
Within the Cleveland Bay area Bureau of Meteorology wind
data is available from Townsville Airport and before 1987 was
available from Cape Cleveland lighthouse, with observations
at U~OOh and 1500h local time. Comparison of the two data
sets (Oliver, 1978) has revealed some marked differences
especially at 1500h. The Cape Cleveland data more closely
indicates the regional airflow, with less modification due to
topography and urban development and therefore is of greater
value in an assessment of wind influences on marine
processes. Wind data is available also from the Townsville
Port Control Building from 1979 onwards.
The percentage occurrence of wind speed versus direction
for Cape Cleveland for the 30 year period from 1957-1986 has
been calculated by the Australian Bureau of Meteorology
(Table 11). The 0900h observations reveal the dominance of
south-east winds throughout the year, with this being
especially pronounced during the winter months. The most
frequent wind speeds at 0900h between March and August are
21-30km/hr, and between September and February are
11-20km/hr. The 1500h observations reveal that east winds
are dominant between January and October, but north-east
winds dominate in November and December. The most frequent
wind speeds at this time are 11-20km/h between August and
47
February and also in June, but they rise to 21-30km/h between
March and May and in July. The regional air flow is most
closely represented by the 0900h records, as the 1500h
records are influenced also by the diurnal sea and land
breeze cycle (Oliver, 1978). The sea breeze, which is more
strongly developed than the land breeze, generally blows
normal to the coast. It is the south-east winds therefore
which exert a major control on wave development over the sea,
and on wind-induced currents in shallow water.
Whilst the 30 year data gives a valuable summary of wind
conditions generally in the Cleveland Bay area it does mask
considerable variations within this period. In order to
examine wind conditions preceding most of the aerial surveys,
and at other times which might be significant in relation to
particular dredging projects for which monthly data has been
compiled, monthly summary wind data were obtained for the
period January 1965 to November 1987 in a form similar to the
30 year data in Table II.
2 Waves
Since July 1975 the Townsville Port Authority has owned,
and the Queensland Beach Protection Authority (BPA) operated,
a Datawell 'Waverider' buoy sited 6km north-east of Cape
Cleveland. For most of this period four 20 minute records
have been taken daily at 0300h, 0900h, 1500h and 2100h. The
BPA has analysed those records by computer using routine and
spectral techniques to obtain the following parameters:
i i
iii
Zero crossing period
(Tz) in seconds
Crest period (Tc)
in seconds
Root mean square wave
height (Hrms) in metres
The average period of all
waves in the record based on
upward zero crossings.
The average period of all the
waves in the record based on
successive crests.
The root mean square of the
heights from the record.
48
iv Significant wave height The average of the highest one
(Hsig) in metres third of waves in the record.
v Maximum recorded wave The highest individual wave in
height (Hmax) in metres the record.
vi Significant period
(Ts) in seconds
The average period of the
highest one third of waves in
the record.
vii Peak energy period
(Tp) in seconds
The wave period corresponding
to the peak of the energy
density spectrum.
This data has been obtained for the period 19 November 1975
to 29 December 19U8. For each calendar month the average,
standard deviation, maximum and minimum have been determined
for each of the 7 parameters (Table 12). (NB There are a few
gaps owing to wave recording failures). As with the monthly
wind data, this enables conditions to be considered in
relation to the monthly dredging records and in the periods
preceding the later aerial surveys. To provide a more
generalised view similar wave statistics have been determined
for each calendar year and dredging year ending on 3D June
(Table 13). In addition, each parameter was plotted on a
computer-drawn annual graph to aid visual inspection of the
data.
The Beach Protection Authority (1988) have summarised
their analysis of this wave data for the period 16 July 1975
to 29 December 1987. Annual graphs for significant wave
height (Hsi g) and peak energy period (Tp) form Figure 18.
Wave period has been tabulated against wave height
occurrences for all the data (Table 14a) and this shows that
waves of D.21-0.40m height and 3.0U-4.99s period occur most
frequently. For the summer data only (Table 14b) and for the
winter data only (Table 14c) the same is the case. This data
(but from 19 November 1975 onwards) is plotted in a different
form as histograms showing percentage of time occurrence of
wave heights (Hsig) .for all wave periods (Figure 19a) and of
wave periods (Tp) for all wave heights (Figure 19b).
49
The predominance of south-east winds which has been
demonstrated in the preceding section, suggests that these
are responsible for producing a high proportion of the waves
recorded near Cape Cleveland. Regretably this 'Waverider'
buoy system measures only vertical water movements and not
wave direction as well, so this cannot be examined in the
records. The relatively small frequently occurring recorded
waves will have been generated mainly in the limited 240km
fetch to tile south-east landward of the Great Barrier Reef,
although some will probably have been generated from the east
and north-east in shorter fetches of 112km and 72km
respectively. When the waves enter shallow water (depth less
than half the wave length) they will start to interact with
the seabed and become refracted. Wave refraction diagrams
have been constructed for 5 second period waves from
south-east, east and north-east (McIntyre and Associates,
1974). The south-east waves (Figure 20a) are partially
refracted before entering Cleveland Bay and wave energy
levels east of about Sandfly Creek are very low. The
orthogonals show that wave energy is mainly concentrated on
the coast west of Townsville Harbour. With this wind
direction waves can be generated also in the 18km fetch of
Cleveland Bay itself and may reach heights of 0.5m before
breaking on the south-east Magnetic Island coast. Easterly
waves (Figure 20b) are also considerably refracted in the bay
resulting in energy levels being very low east of about
Alligator Creek, but considerably greater on the western
coasts. North-east waves (Figure 20c) approach Cleveland Bay
from its most open direction, therefore refraction and
dissipation of energy are at their least, but the relatively
short fetch limits potential wave size. Cape Cleveland
provides some shelter from north-east waves and the
orthogonals indicate relatively low energy levels eastwards
from between Alligator and Crocodile Creeks. Most of this
wave energy is concentrated on the coasts west of Alligator
Creek.
50
Only on rare occasions, such as when a tropical cyclone
passes near Cleveland Bay are moderate to large waves likely
to be generated from any other direction. Then, normally
sheltered, low energy coasts may experience high energy waves
and suffer considerable erosion.
3 Tides and Tidal Currents
Tides in the Cleveland Bay area are mainly semi-diurnal
in type with a range of up to 4.0m during spring tides and
down to O.Om at neap tides, during 1988 (British Admiralty
Tide Tables for Townsville, 198B). Easton (1970) notes that
the solar influence on tides along the Queensland coast
increases north of Mackay and this results in an increase in
neap to spring variations. At extreme neap tides they become
almost diurnal in type at Townsville, whereas at spring tides
successive semi-diurnal tides may differ by about 1m in
height.
Tidal ebb and flood generates important tidal currents
especially during the higher range spring tides. Orogue
measurements made by the Townsville Port Authority on a
number of different dates and tidal conditions (although
avoiding neap tides) are amalgamated into Figure 21a and b
(McIntyre and Associates, 1974). The flood tide (Figure 21a)
is shown entering Cleveland_Bay in three streams. The first
originates from the east, swings round Cape Cleveland and
moves across the bay south-westwards with speeds of up to
0.5ms- 1. The second stream enters the bay from the north and
swings closer to Magnetic Island, reaching speeds of 0.2 and
-10.3ms . The third stream enters the bay through West
Channel between Magnetic Island and Cape Pallarenda, and
-1
reaches speeds of 0.7ms The opposing flood currents meet
off Cape Pallarenda. On the ebb tide the current continues
to flow south-eastward through West Channel reaching speeds
of O.3ms- 1 on spring tides. Water therefore leaves the bay
either close to Magnetic Island in a northerly direction at
51
-1
speeds of up to 0.4ms ,or towards the north-east at the
same speed on maximum spring tides.
Belperio (197B) from a series of spot measurements of
tidal current confirmed this pattern, but took no ebb current
measurements in West Channel. Furthermore he gives no
indications of dates or tidal ranges when the measurements
were made. Carter and Johnson (19U7) used recording current
meters at 3 sites in Cleveland Bay (Figure 1) to measure
water depth, and current speed and direction during a full
neap to spring tidal cycle. Their findings are not presented
alone, but are amalgamated with earlier published
observations. They indicate that the tide floods into
Cleveland Bay in a "south to south-south-east (170 0 -230 0 )
direction" (there is an obvious discrepency here) and rotates
anticlockwise to ebb north-north-east to north-east
(030 0 _U50 0 ). At the eastern end of West Channel the flood is
more westerly and the ebb more easterly, and furthermore
during neap tides a weak current floods and ebbs in a
consistently north-east direction. The source of this
information relating to West Channel is unclear as none of
their current meters was placed here and a current flowing at
right angles to West Channel is very difficult to explain.
Overall this pattern described by Carter and Johnson is
similar to that revealed by the Townsville Port Authority
drogue measurements except that the latter indicate a
south-eastward flow through West Channel. A close linear
relationship is reported by Carter and Johnson between tidal
magnitude and measured bottom currents. Ouring neap tides
(U.5-0.8m range) currents are irregular in direction and less
than 0.05ms- 1 velocity; during spring tides (2.3-3.6m range)
currents vary between U.2 and 0.3ms- 1 with minor asymmetry
between the slightly stronger flood and slightly weaker ebb,
but with regular orientation.
52
C Sediment Movement in the Cleveland Bay Area
Except close to the Magnetic Island fringing coral
reefs, coastal sediment and sediment on the neighbouring
seabed is dominantly siliceous and has a terrigenous source.
The main source of sediment in Cleveland Bay is the small
rivers and creeks which flow into it, although the damming of
Ross River is likely to have reduced the overall quantity
significantly. It has been noted above also that the very
large Burdekin River further south is capable of delivering
huge quantities of sediment to the coast during times of
major floods associated with tropical cyclones. Belperio
(1978) has suggested that at such times a turbulent jet from
the Burdekin is turned north to north-westwards from the
mouth due to the prevailing south-east winds and waves and
its influence may be felt as far as Townsville. (Geostrophic
effects and coastal trapping, together with the effects of
the wind, provide an alternative explanation of this north to
north-westward movement.) As an example Belperio considers a
long period of heavy rainfall between 15 January and B
February 1974, which followed Cyclone Una in December 1973,
during which the average flow of the Burdekin was 16,000
cumecs and the total discharge 33xl0 9m3 . Such rare but
massive inputs of fresh water must have a considerable effect
on the circulation pattern, sediment transport, salinity and
biota. It is possible that fine sediment from the Burdekin
was deposited in Cleveland Bay as a result of this event.
As the Cape Cleveland 0900h records show, 60% of winds
blow from the east and south-east, and they are almost solely
-1from these directions when the wind velocity is over 7.5ms .
As a result wind-induced surface water currents move
predominantly towards the west and north-west carrying
suspended sediment alongshore. Belperio (1978) reports
observing such surface currents moving over tidal flood and
53
ebb currents during spring tides, although the tidal currents
were deflected to some degree towards the north-west.
Measurements taken off Cape Cleveland and in West Channel
indicate that a 7-10ms- 1 east or south-east wind is
sufficient to obliterate the southward moving flood tidal
current and set up a unidirectional current around each
headland so that inner shelf water is moving through
Cleveland Bay and the adjacent bays in a north-westward
direction. This current, combined with wind-induced currents
in south Cleveland Bay induces a major current flowing
southwards along the west leeward coast of Cape Cleveland,
which is reinforced by the tidal flood current. Belperio
found the best sorted sub-tidal sediments in this area, which
is also one where, unusually, sub-tidal bed load movement
occurs. Moderately sorted sand, from sub-aqueous erosion of
deep weathered rock along Cape Cleveland, moves south by
ripple migration and supplies sediment to the intertidal
flats along the south coast of Cleveland Bay. Wave induced
longshore drift is then claimed by Belperio to result in
substantial suspended sediment movement westwards past
Townsville and through West Channel into Halifax Bay. Wind
induced surface currents were observed to have a velocity of
U.2-0.3ms- 1 in open water areas, but reached 0.5ms- 1 in the
constricted West Channel.
To study the movement of wind-induced currents below the
water surface Woodhead sea-bed drifters (Phillips, 1970) were
released by Belperio at times of low tidal range but strong
wind and wave activity. From the recovery pattern it was
shown (Figure 22) that the drifters had moved alongshore
north-westwards, and a particularly strong sea-bed water
movement had been demonstrated around Cape Cleveland and
southwards along its west, leeward side and also through West
Channel into Halifax Bay. From these results Belperio
concluded that the entire water column in Cleveland Bay and
the adjacent bays is essentially wind driven when wind
54
-1
velocity exceeds 7-10ms ,and this will influence both
suspended sediment and bed load movement. This conclusion
that the entire water column moves in a downwind direction is
contrary to findings from seabed drifter investigations in
Morecambe Bay, north-west England (a temperate storm wave
environment) where strong winds blowing from the prevailing
westerly quarter set up counter currents near the seabed
moving from east to west (Phillips, 1968 and 1969). Although
Cleveland Bay and Morecambe Bay are of similar dimensions, it
may be that West Channel acts as an escape route for such
wind driven water in Cleveland Bay and prevents development
of counter currents. Further current measurements are
required to clarify this.
Wind waves and wind-induced currents, as well as tidal
currents in restricted localities such as West Channel on
spring tides, are strong enough to entrain fine sediment from
the bed of Cleveland Bay and even fine to medium sand on
occasions. Belperio (1978) has mapped suspended sediment
concentrations under different sea states (Figure 23). For
smooth to slight seas, less than 10ppm were measured except
over the intertidal flats, where wave action would be
dominant. Ouring slight to moderate seas (wind velocity
5.U-7.0 ms- 1 and wave height up to 0.8m) a narrow continuous
1-2km turbid coastal zone developed with over 10ppm. With
moderate to rough seas (winds 7.5-9.5ms- l , wave heights
1.U-l.8m) the coastal turbid zone widened to 2-7km. Under
rough sea conditions (winds lO-12.5ms- 1, wave heights
1.9-2.5m) the entire bay became turbid, but effective
transport off Cape Cleveland did not extend beyond 5km from
the tip of the headland. In addition a marked plume of
turbid water extended round Cape Cleveland and
south-westwards into Cleveland Bay indicating, according to
Belperio, advective transport of suspended sediment from
Bowling Green Bay.
55
Transport of sand along the inter-tidal zone and in the
surf zone is primarily the result of waves breaking obliquely
to the coast. Belperio (1978) calculated a transport rate of
50 tonnes per day in the surf zone at Rowes Bay under
moderate sea conditions. If these prevailed for 71 days in a
year, north-westward transport of sand would be about 3,500
tones yr -1, but would be supplemented by higher rates under
rough sea conditions. The loss of sand from the Townsville
beaches along The Strand and the southern end of Rowes Bay
result from Townsville Harbour interrupting the natural
north-westward sediment movement from south Cleveland Bay and
especially Ross River and Ross Creek.
Recently the existence of a further water movement in
Cleveland Bay has been suggested (E. Wolanski, personal
communication 1988). This involves a narrow inshore strip of
water moving very slowly eastwards along the south Cleveland
Bay coast, then northwards along the west Cape Cleveland
coast to finally escape as a jet past the tip of the
headland. This is produced by the development of baroclinic
and barotropic coastal boundary layers in wet and dry seasons
respectively. In the dry season this inhibits mixing of
estuarine and shelf waters and limits estuary flushing.
Pollutants would then either be retained in an estuary, such
as Sandfly Creek, or would escape only into this narrow
coastal water body to be evacuated from there extremely
slowly. The sediment in this zone would not be moved by this
slow moving water but, especially the fine fraction, would be
likely to become very polluted.
56
CHAPTER 4
An Assessment of the Influence of Dredging on Sediment
Movement, and Growth of Mangroves, Corals and Seagrass in
Cleveland Bay.
From sidescan seismic profiling and vibracore sampling,
Carter and Johnson (1987) have produced an isopach map of
dredge spoil distribution in Cleveland Bay and a map showing
surficial sediment facies distribution beneath the spoil
(Figure 24). A maximum thickness of 50 em of dredged material
from Townsville Harbour and the Platypus Channel was found in
the vicinity of the two present dump sites east of Magnetic
Island and seaward of Ross River mouth. The 50cm isopach was
closely surrounded by the 30 em isopach near the landward dump
site, but from the main seaward dumping ground the 30cm
isopach extended south-eastwards and broadened towards the
south-east coast of the bay. The IDem isopach surrounded the
two centres of concentrations in a triangular shape with its
apex near the north-east tip of Magnetic Island and its base
broadly paralleling the south and south-east coasts of the
bay between the 5m and 21n isobaths. A further concentration
of dredge spoil with a maximum thickness of 30 em was
identified west of Platypus Channel and south-east of Middle
Reef and probably relates to the dump site used before about
the mid-1960's.
The aim of the present project has been to assess the
influence of dredging on the coastline and intertidal zone as
revealed by aerial surveys between 1941 and 1988 and the two
series of ground surveys which exist. The higher quality air
photographs taken at times of clear under-water visibility,
and some of the ground surveys, have enabled this assessment
to include the adjacent part of the subtidal zone at certain
dates. For the period prior to aerial surveys, it is
possible to make only a general assessment of the likely
57
effects, based on relatively scant dredging data and
contemporary observations, but drawing on present knowledge
of processes.
1 Influence of Dredging between 1883 and 1964
Taking into account availability not only of aerial
surveys but also of detailed dredging records and process
data, the influence of dredging will be assessed for two time
periods, 1883-1964 and 1965-1988. For the former period, the
history of dredging has been examined in Chapter 1, data on
dredged depths has been compiled into Table 1 and the
intermittent annual dredging records are listed in Table 2.
Whilst a fair record of dredging exists in relation to the
development of Townsville Harbour and the maintenance of
depths suitable for shipping, only two written records have
been found concerning the dump sites used for disposal of the
dredged material. In 1883 it was "deposited close to
Magnetic Island, about 5 miles distant from where it is
raised" (Annual Reports of the Engineer of Harbours & Rivers
on Works, 1876-1928), that is off Cockle Bay or the south end
of Nelly Bay. The report for 1891-92 notes that "The cost of
carrying (dredge spoil) ... will possibly be slightly greater
in the coming year as all the dredgings will be carried to
Cockle Bay, in Magnetic Island, it not being advisable to
deposit any eastward of the Eastern Breakwater". (The
comparison with earlier costs probably takes into account the
fact that much early dredging provided infi11 for
reclamations, and it is not a direct comparison with the
dumping described in 1883). It seems probable that these two
references are to the same site, but how long this was used
is unknown. The next information about dump sites is that
before the early to mid 1960's dumping was carried out south
of Middle Reef, but for how long is again unknown (N.
Butterworth, personal communication 1988).
58
When considering dredge spoil it is important to
differentiate between that obtained during developmental and
maintenance dredging. Developmental dredging was of major
importance in the late 1800's and early 1900's when the
harbour was being constructed initially and the Platypus
Channel was being excavated. Many references were made in
the early reports to the difficulties of removing the
"tenacious clay", "stiff clay" and "sandstone" which were
encountered as well as softer mud and clay. Excavations for
the Casino complex, now built adjacent to the Western
Breakwater, have revealed not only the rapid rate of
sedimentation there since that breakwater was constructed in
the 1880's, but that the weathered Pleistocene basement is
almost at the 1880's surface with only a thin bay-sediment
veneer over it in places (Carter and Johnson 1987).
Elsewhere a sticky mangrove mud intervenes between the
bay-sediment and the Pleistocene deposits. The top of the
Pleistocene marks an abrupt increase in lithification and
below it is a sequence, over 7m thick, of deeply weathered
clays, quartz sand and a marine she11bed. Many of the beds
contain carbonate or ferro-magnesian nodules resulting from
deep sub-aerial weathering in the tropical climate. When
this more lithified material forms dredge spoil it is
probably relatively immobile after dumping and is likely to
cause the raising of the seabed at the dump site. It will
almost permanently bury the sediment, coral or seagrass
previously on the surface of the seabed. This may have had a
pronounced effect off Cockle Bay in the late 1800's and for
as long as this dump site was in use and developmental
dredging was being carried out. The sediment which is
released from this more 1ithified state is likely to be more
mobile and will be transported in suspension or as bedload
and be more widely dispersed by waves and currents. More
research is needed into tidal and wind-induced current flows
and wave directions in West Channel to resolve the apparent
contradictions in the results of different measurements made
59
to date. Only then will it be possible with reasonable
certainty to determine in which direction finer sediment
would be carried from a dump site off Cockle Bay.
Nevertheless it does seem likely that some fine sediment
would settle in the shallow water on the extensive coral reef
flat north-west of the bay and its presence there has been
noted by Spenceley (1977), seaward of the mangrove fringe.
Maintenance dredging, to retain the depth excavated by
developmental dredging, involves the removal of
unconsolidated sand and mud deposited in the harbour and
Platypus Channel by Ross Creek and as a result of general
sediment movements in the bay controlled by wind, wave and
tidal processes. Taylor (1980) claimed that O.9-1.2m of
sediment per year accumulated in the berths in "normal
weather" and even greater thicknesses in Platypus Channel.
Throughout the period of dredging from 1883 onwards it has
been observed that deposition of sediment in the harbour and
channel is especially rapid when a tropical cyclone occurs
followed by major river flooding. The first such occurrence
noted in the reports was in March 1890, followed by 24
January 1892, April 1894, January 1896 (Cyclone Sigma), March
1903, 1908, two in 1910, 18 February 1940, 7 April 1940, 28
March 1944, March 1946, 6 March 1956 (Cyclone Agnes), 24
Oecember 1971 (Cyclone Althea) and February 1976. After such
events a considerable amount of maintenance dredging was
necessary to restore depths and therefore large quantities of
fine sediments were carried out to the dump site(s). From
the site off Cockle Bay it is likely that some of this
sediment was transferred onto the neighbouring coral reef
flats, although some was probably moved further away by tidal
currents south-eastwards (Townsville Port Authority drogue
measurements) or north-westwards by sea-bed currents induced
by strong south-east winds (Belperio's sea-bed drifter
investigations). A third influence, north-east tidal
currents across West Channel reported by Carter and Johnson
60
would have transferred most of the dredged sediment onto the
south-west coast of Magnetic Island and its adjacent coral
reef. As noted earlier however a tidal current flowing in
this direction is very difficult to explain and appears
improbable.
The dump site south of Middle Reef, which was used prior
to the early to mid-1960's, would have been in a more central
position on a cross-section of the eastern end of West
Channel. It is important to note however that no written
record or detailed description of its location has been
found. Fine mobile sediment is likely to have affected
Middle Reef itself but it probably had less effect on the
nearby coasts, than that from the Cockle Bay dump site. This
sediment was probably either carried into Cleveland Bay by
tidal currents or moved north-westwards by currents induced
by strong south-east winds. In the latter instance some of
the fine sediment is likely to have been deposited on the
Cape Pallarenda-Shelly Beach foreland.
2 Influence of Dredging between 1965 and 1988
From 1965 onwards much more detailed information exists
about dredging and wind and wave conditions in Cleveland Bay.
Monthly dredging records for the S.D. 'Townsville' 1965-1983
are presented in Table 3 and Figure 5. Records for the
T.S.D. 'Sir Thomas Hiley' 1974-1976 are given in Table 2, and
for 1983-1988 in Table 4. Annual dredging records
amalgamating all these are plotted in Figure 4. All these
records are examined in Chapter 1. Throughout this period it
is understood that the present shallow draft dump site
south-east of Magnetic Island (Figure 1) has been in use,
although no written record has been found of when it was
first used. Similarly it is not known when the deep draft
dump site east of Magnetic Island began to be used, but it is
believed to have been from the early 1970's onwards. As
61
indicated in Chapter 3 monthly summary wind data has been
obtained for Cape Cleveland from 1965 to 1987 and wave data
frolo the nearby wave recorder from 1975 to 1987. The
dredging data, wind and wave data and general information on
tides and currents will be used in the following assessment
of the influence of dredging on the changes identified from
the aerial surveys and described in Chapter 2.
a) Coastline and Intertidal Changes
Along most of the coasts of Cleveland Bay and Magnetic
Island these changes were slight between about 1941 and 1988.
East of the east mouth of Shelly Creek the sand beach which
was originally seaward of the mangroves was driven landward
through them. Erosion near the mouths of the rivers and
creeks between Ross River and Cocoa Creek between 1941 and
1973 were noted by McIntyre and Associates (1974). In all
these cases the erosion is attributable to natural cyclone
effects and is of a similar type to that observed along the
east Burdekin delta coast during the same period (Pringle,
1983 and 1984). Erosion of the upper sand beach at the
south-eastern end of The Strand in Townsville during the
period was not a natural process but resulted from the
HarDour interrupting the natural longshore sediment movement
north-westwards from the south coast of Cleveland Bay.
Only near Ross River mouth have larger scale coastal
changes taken place and these are directly linked to
dredging. Reclamations along the west coast of Ross River
mouth have been taking place for a long period as the Harbour
and adjacent industrial area have expanded. Between 1968 and
1970, 2,319,660m3 of sand were pumped ashore from the
adjacent intertidal sandbanks for a major reclamation here.
In 1979-tlO about 400,OOOm3 of sand was removed from the Ross
River bed immediately upstream of Goondi Creek for an 8ha
reclamation east of the Harbour's Eastern Breakwater. As
62
relatively little sediment is being delivered to the coast by
Ross River because of the presence of the Ross River dam
completed in 1973, this sand is likely to be replaced only
very slowly. In addition to this sediment removal,
developmental dredging took place in the Ross River channel
between 1977 and the early 1980's and this sediment was
mainly pumped ashore although small quantities were taken to
the shallow draft dump site south-east of Magnetic Island.
Maintenance dredging has been undertaken here since and the
sediment has been disposed of similarly. As was noted in
Chapter 3, sediment in Ross River mouth and seaward of it,
was found in the early 1980's to be heavily polluted by
sewage effluent from the outfall on the east side of the
mouth. This was likely to have been the case from at least
the beginning of the period at present under consideration,
namely 1965. Polluted sediment would therefore have been
incorporated in the land reclamations and would also have
been carried to the shallow draft dump site in Cleveland Bay.
Further changes have been brought about by the construction
between 1981 and 1985, of an angled harbour wall east of the
Eastern Breakwater and extending across part of the
intertidal sandbanks. The result of all this dredging and
construction work in the Ross River mouth area has been to
move the main channel westwards froln its former position
across the intertidal zone, so that it now lies almost due
north of the mouth. The presence of the angled harbour wall
has caused some sedimentation landward of it on the west side
of the channel.
b) Changes to the Mangrove Coasts
Changes to the outline of the mangrove coasts were
generally slight during this period. East of the east mouth
of Shelly Creek mangroves have been killed due to exposure to
wave action, after the sand beach which had protected them
was driven landward through them. In the most sheltered part
off Rowes Bay mangroves extended a little. Along the south
63
and south-east Cleveland Bay coasts, McIntyre and Associates
(1974) had earlier, between 1941 and 1959, observed about 50m
of recession between Sandfly and Alligator Creeks and about
30m of recession along the west banks of the mouths of
Alligator, Crocodile and Cocoa Creeks. This was attributed
to cyclone effects. Ouring the period now under
consideration the extent of the coastal mangrove belt changed
very little. There was a slight extension along the coast at
the north-east end of Laun's Beach and mangrove colonization
be9an on the north-east side of White Rock Bay. Such changes
must be considered as natural.
The only more marked change to the mangrove coasts
occurred along ~he south-west coast of Magnetic Island. The
1974 aerial survey showed considerable damage to what had
been a dense and continuous belt of mangroves at the times of
the 1959 and 1961 aerial surveys. By 1974 a broad strip of
mangroves had been destroyed landward of, but parallel to,
the seaward fringe. Further investigations have revealed
that Cyclone Althea in December 1971 caused this destruction
(Spenceley, 1977). It occurred primarily in the Rhizophora
zone, where some wind throw took place immediately, but
progressively, during the next 6 years, over 50% of the
Rhizophora spp. were killed. The reason for this is unclear,
but may be the result of an influx of fresh water, sediment
overloading and blocking of pores, or fungal activity.
Furthermore Gill and Tomlinson (1969) found that Rhizophora
spp. lost their ability to regenerate by shoot development on
reaching maturity. Only if sediment overloadin9 was the
cause, could dredging and more specifically the dumping of
dredge spoil be in any way to blame. This cause was not
proved, but if it was a contributory factor, the dumping of
enormous quantities of dredge spoil in the early and mid
1970's may have played a significant part. (This will be
examined in more detail below in relation to changes in
seagrass cover). Later aerial surveys, especially those of
64
1981 and 1985 revealed the steady recovery of this damaged
strip of Inangroves.
c) Changes to the Coasts with Fringing Coral Reefs
As shown in Chapter 2, fringing coral reefs have
developed in the Cleveland Bay area only along the coasts of
Magnetic Island. The most extensive coral reef lies off the
south-west coast. The likelihood of fine sediment being
carried onto this reef flat from the earlier dump sites near
Cockle Bay and south of Middle Reef has been considered
above. During the period 1965-1988 it is believed that
neither of these sites was in use. No marked change in
sediment distribution was identified from the aerial surveys,
although there were changes in seagrass growth in the
sediment, which will be considered below. Movement of fine
sediment to this locality from the present deep draft and
shallow draft dump sites (Figure 1) is possible by tidal
flood currents. It might be possible also by currents
induced by strong north-east winds, but deflected
north-westwards through West Channel.
The only changes on the coral reefs along the south-east
coast of Magnetic Island, which could be identified from the
aerial surveys at the scale of 1:12,000, were in the lower
beach sand cover on the Picnic Bay, Nelly Bay and Geoffrey
Bay reefs. The characteristics of this sediment which is
partly terrigenous and derived from granite weathering
primarily, and partly carbonate from the erosion of the reef
are considered in detail by Smith (1974 and 1978). The
smaller Picnic and Geoffrey Bays which are sheltered by
headlands from wind, wave and tidal effects from the
north-east and east, showed the smallest changes in the
extent of lower beach cover over the inner reef flat.
Conversely the larger and more exposed Nelly Bay showed
65
greater lower beach change associated with sand bar
development along its seaward edge. The changes seen in all
three bays will have partly resulted from the effects of
refracted waves generated by the prevailing south-east winds
on the continental shelf landward of the Great Barrier Reef.
However as noted in Chapter 3, the south-east wind is capable
also of generating waves over the 18km fetch within Cleveland
Bay and these unrefracted waves are probably responsible for
the orientation of the beaches along the south-east coast of
Magnetic Island, together with the changes which have been
observed on them. No clear trend of expansion or contraction
of these lower beaches was identifiable over the period
1965-1988 and it therefore appears unlikely that dumped
dredge spoil is being redistributed onto those beaches.
Collins (1987) notes that there have been many
unsubstantiated claims locally that dredging is having a
harmful effect on these coral reefs. Despite many years of
detailed biological studies on them he has found no evidence
of this, but notes that two natural events did temporarily
damage the corals. The first was the freshwater dilution
associated with the rainfall from Cyclones Althea and Bronwyn
in December 1971 and January 1972 which caused the deaths of
many shallow water colonies. The effects however were
obliterated in about 10 years, after some regrowth and some
new growth on the dead skeletons. The second event was a
large scale 'bleaching' in 1982 which caused the depletion of
certain species. Small scale 'bleaching' is common on
Magnetic Island reefs and may be the result of such stress
factors as high summer temperatures or rain dilution of sea
water. The reefs had largely recovered from the 1982 event
within 5 years. Thus searching for causes of change, it must
be remembered that there are a range of natural events as
well as human effects which can influence these.
66
d) Changes to the Seagrass Beds
Changes to the seagrass beds around Cleveland Bay and
Magnetic Island, as identified from the aerial surveys, were
the most marked coastal changes to be found. Although
slightly outside the period under consideration at present,
1965-1988, the 1959 and 1961 aerial surveys will be referred
to, as well as the later surveys.
The distribution of seagrass beds in the Great Barrier
Reef lagoon have been mapped recently during a series of
field studies by the Northern Fisheries Research Centre
(Coles et al, 1987a & 1987b). Their field survey of the
Cleveland Bay area was carried out in October 1987 and is
currently being analysed, but their draft maps were made
available for this project (Figure 25). The maps were drawn
from data collected on a series of diving transects at right
angles to the coast, as well as by inspection of the
intertidal zone on the transect lines.
Determining seagrass distribution from aerial surveys
can never be as accurate as from detailed ground and
under-water surveys, because of the hei9ht from which the
coastal area is being viewed. Aerial surveys do have the
advantage however of providing a broad overview of the area
and this may be especially important in more inaccessible
places. There can be specific problems in identifying
seagrass beds on aerial photographs (R.G. Coles personal
communication, 1988), firstly because the common algae
Caulerpa may be difficult to separate from seagrass. (As
little Caulerpa is thought to be present in Cleveland Bay,
this is not a serio~s problem here). Secondly water depth
limits the area over which seagrass can be recognised and
Coles believes it is not generally visible in water with a
67
depth over 1m. In Cleveland Bay the densest seagrass growth
is between +1.0m and -O.5m Chart Datum (CD), however it
generally extends to about -2.0m CD, ego seaward of The
Strand, Townsville, and reaches -10m CD near Magnetic Island.
From the aerial surveys used in this project it was certainly
not possible to see the sea-bed in the deeper areas, where
seagrass was located in the field surveys (Figure 25).
Seagrass was not visible also along the south-west coasts of
Cleveland Bay where greater turbidity occurs than along the
more sheltered south and south-east coasts. Even in the
intertidal zone it is not possible to locate low growing and
thinly spread seagrass on the aerial photographs. Before
seagrass distribution was mapped from these aerial
photographs they were carefully inspected and discussed with
R. G. Coles and W. J. Lee Long at the Northern Fisheries
Research Centre, to ensure as high a level of accuracy as
possible. When seagrass distribution is to be compared on a
series of aerial surveys further difficulty may arise unless
all the surveys are flown at the same time of year, because
there can be marked changes in the pattern of growth between
summer and winter. The aerial surveys referred to below were
all flown in winter between late-May and mid-August, except
for the 1973 survey which was flown in early October and the
1978 survey which was flown on 28 November (Table 5).
Location of seagrass beds is surer on colour aerial
photographs, which were available from the surveys between
1974 and 1985; however, using experience gained with these,
seagrass could be identified with reasonable certainty on the
black and white photographs from the earlier surveys.
The seagrass distribution pattern mapped from a series
of aerial surveys for different sections of the coast of
Cleveland Bay and Magnetic Island were described in detail in
Chapter 2 and are shown in Figures 6,10 and 13. In the
Shelly Beach - Cape Pallarenda section (Figure 6) areas of
68
seagrass were clearly visible in the central and coastward
parts of the foreland on the 1959, 1981 and 1985 aerial
photographs, but none showed on the 1974 photographs despite
their high quality and good under-water visibility. Between
Sandfly and Cocoa Creeks (Figure 6) no seagrass could be
located on the 1974 aerial photographs, however it was
present north-eastwards from the mouth of Crocodile Creek in
1Y78 and 1981, and had extended along the whole section by
the 1985 survey. Between Cocoa Creek and Cape Cleveland some
seagrass was visible in 1961, none was observed on the 1973
survey and very little on the 1974 survey, but in the later
case some might have been obscured by very turbid water
conditions between Cape Cleveland and Long Beach. The
sUbsequent aerial surveys in 1978, 1981 and 1985 revealed a
steady increase in extent and density of seagrass beds.
Along the south-west coast of Magnetic Island (Figure 13)
seagrass was visible seaward of Bolger and Young Bays, on the
landward side of the coral reef flat further south and along
the shore between Cockle Bay and Nobby Head, on the 1959 and
1961 aerial photographs. In 1974 however none was visible,
despite the high quality of the photographs and clear
under-water visibility. By the 1978 survey, limited areas of
seagrass were visible again, and these subsequently extended
as shown on the 1981 and 1Y85 surveys.
The overall sequence of change in seagrass cover in the
Cleveland Bay and Magnetic Island area was from a moderate
cover in 1959 and 1961, to almost none in 1974, followed by a
steady increase in cover again from 1978 to 1985. The
relatively long gap between the 1961 and 1974 aerial surveys
makes it impossible to determine the date of disappearance
precisely. (The 1973 survey was useable only along some
coasts owing to part of it being flown at HW). However there
were some noteworthy natural events between December 1971 and
February 1974 which may have played a part, and also in 1972
the largest dredging programme ever undertaken by the Port of
69
Townsville in a short period began. The importance of such
ecological factors as substrate stability, water clarity and
salinity in determining the distribution of different species
of seagrass is poorly understood (Lanyon, 1986) and this
increases the difficulty of determining the likely cause.
The major natural events were associated with Cyclone
'Althea' in December 1971, Cyclone 'Bronwyn' in January 1972
which affected the Townsville Area as a rain depression,
Cyclone 'Una' in December 1973 and a long period of heavy
rainfall which followed in January and February 1974. Major
floods were produced in the Burdekin River in January 1972
and January 1974 (Table 10) and therefore there was a massive
input of fresh water into the nearshore zone, carrying with
it a large quantity of terrigenous sediment. As shown in
Chapter 3 such a sediment plume curves north and
north-westward from the mouth of the Burdekin and its
influence may reach Cleveland Bay. In addition there would
be a fresh water and sediment influx to the bay from the
smaller rivers draining directly into it. In Chapter 1 it
was noted that 458,733m3 of sediment had been deposited in
the Pl atypus Channel, reduci ng its depth by 1.4m, after
Cyclone 'Althea'. This was subsequently removed by the S.D.
'Townsville' in 1972 and deposited at the shallow draft dump
site east of Magnetic Island.
The enormous developmental dredging programme began in
the latter part of 1972 and caused the total annual dredging
figures to soar to a peak of 2,112,879 tonnes in 1973/4. It
began with the dredging of a new 'dog-leg' channel to extend
the Platypus Channel seaward, as shown in Chapter 1. It was
cut in relatively soft material, probably the Holocene mud
identified by Carter and Johnson (1987), and this dredge
spoil was deposited at the deep draft dump site. Both this,
and the sediment from the Ross River/Ross Creek floods
following Cyclone 'Althea', is likely to have been fine so
70
that it could have been readily redistributed in the bay from
the two dump sites in response to tidal and wind-induced
currents, especially during the subsequent high energy event
of Cyclone 'Una'. Developmental dredging within the Harbour
would have been in the more lithified Pleistocene deposits
and probably this material would have been less liable to
redistribution from the dump sites.
It seems likely therefore that a large quantity of fine
sediment was spread widely over the bed and coastal zone of
Cleveland Bay as a result partly of the natural cyclone
events and the subsequent river floods and partly as a result
of the huge dredging programme which reached its peak between
1972 and 1975. It is possible therefore that much of the
seagrass was buried or was so adversely affected by the high
turbidity and/or high levels of fresh water that much of it
died. The seagrass was able to recover and showed early
signs of this by 1978, and a more complete recovery by the
early 1980's.
71
CHAPTER 5
Conclusions
In an environment such as that of the coast and
near-shore zone of Cleveland Bay many variable processes
interact to shape the physical and biological evolution. The
geoiogy and climate in the coastal catchments influence rock
weathering, erosion, river regime and therefore fluvial
sediment supply to the coast. Marine processes are
controlled by wind, wave and tidal regimes. The wind
produces waves not only within the bay but in the available
fetch seaward and also may produce currents especially in
shallow water. The alternate flooding and ebbing of the
tides moves the zone of breaking waves back and forth across
the intertidal zone and also induces tidal flood and ebb
currents which reach maximum velocity on spring tides in
restricted channels. In addition to these natural catchment
and marine processes man may have a considerable effect,
through such activities as constructing dams on rivers, which
trap not only water but sediment; concentrating pollution at
particular localities where sewage and industrial effluent
flows out to the coast; and dredging sediment from one
locality and dumping it in another. Where such a wide range
of natural and man induced processes are interacting,
isolating the effects of anyone particular process is
difficult and complicated. However, against such a
background is set this assessment of the influence of
dredging in Cleveland Bay.
For the first BI years of dredging, from 1883 to 1964,
records of amounts and localities of dredging in the
Townsville Harbour area are intermittent. The fact that
amounts of dredged material are recorded in several different
units which cannot be related to each other lessens their
usefulness further. The greatest problem concerning this
72
earlier period however is shortage of information about dump
sites; only for 1883 and 1893 do written records exist which
indicate that dredge spoil was dumped near Cockle Bay,
Magnetic Island. Verbal information only suggests that
before the mid 1960's a dump site south of Middle Reef was
used, but for what exact period is unknown. Because of these
serious limitations in the records, it was possible to assess
the effects of dredging only very generally in the light of
present knowledge and understanding of processes. The more
lithified dredge spoil from developmental dredging,
especially in the harbour area, will not have been so liable
to redistribution from the dump site as is the unconsolidated
finer sediment from maintenance dredging. The latter is
likely to have been moved from the dump site by tidal and
wind-induced currents, but whether this was predominantly in
an eastward or westward direction is uncertain from present
knowledge of these currents, as the use of different methods
to measure these has led to some contrasting results. It
seems possible however that some of the fine sediment from
the dump sites near Cockle Bay and Middle Reef was
subsequently deposited on the large adjacent coral reef flat,
which extends from the south-west coast of Magnetic Island.
From 1965 onwards detailed dredging records which show
localities and amounts of dredging have been kept by the
Townsville Port Authority. Throughout this period the main
dredge spoil dump site has been the shallow draft site
south-east of Magnetic Island with a deep draft dump site
east of Magnetic Island being used in addition from the early
1970's onwards. A permit for continued dumping at these two
sites was issued in 1988. Also, more wind, wave and tidal
data has become available for all or part of this period,
which greatly aids understanding of the processes influencing
sediment movement in Cleveland Bay. Aerial surveys have been
carried out in this area from 1941 onwards and although they
were relatively infrequent and their cover was variable
73
during the next 30 years, in the 1970's and 1980's
comprehensive coastal surveys have been undertaken every 3 to
4 years. These aerial surveys have been used to investigate
coastline and intertidal changes and, on occasions of clear
under-water visibility, also changes in adjacent parts of the
subtidal zone. An assessment has been made of the influence
of dredging on these changes.
The most direct effect of dredging has been near the
mouth of Ross River. Here 2,319,660m3 of sand were removed
from the intertidal sandbanks between 1968 and 1970 to be
pumped ashore for adjacent land reclamation. A further
400,OOOm3 of sand was removed in 1979-80 from the Ross River
bed imlnediate1y upstream of Goondi Creek, for land
reclamation on the east side of the Harbour's Eastern
Breakwater. The presence of the Ross River Dam upstream,
which traps sediment, is likely to result in only slow
natural replenishment of this sand. The sand removal plus
developmental dredging between 1977 and the early 1980's in
the Ross River channel, followed by maintenance dredging, has
had two effects. Firstly the channel has been moved
westwards from its previous natural route across the
intertidal zone, which has affected the pattern of
sedimentation. Secondly the sediment, which has been proved
to be highly polluted from the sewage outfall on the east
side of the Ross River mouth, has been used for land
reclamation mainly, but some has been carried to the shallow
draft dumping ground south-east of Magnetic Island from which
it is likely to have spread out subsequently in response to
current movements.
The dumping of very large quantities of dredged sediment
in the early and mid 1970's probably played a significant
part in more widespread changes to the seagrass beds
throughout the Cleveland Bay area. The moderate seagrass
cover visible on the 1959 and 1961 aerial surveys was reduced
74
to almost none by the time of the 1974 survey, but showed the
beginnings of a recovery in 1978 and subsequently a steady
expansion on the 1981 and 1985 aerial surveys. The long
interval in the 1960's and early 1970's when no aerial survey
suitable for assessing seagrass cover was flown is
unfortunate and makes it difficult to pinpoint more precisely
the time of seagrass cover destruction. However it seems
highly likely that it occurred in the early 1970's when major
natural events and dredging activities combined to deliver a
huge amount of fine sediment for distribution in Cleveland
Bay. Cyc10 ne 'A Ithea' i n Dec embe r 1971, f 01 lowed
by the rain depression produced by Cyclone 'Bronwyn' in
January 1972, and Cyclone 'Una' in December 1973, followed by
a long period of heavy rainfall in January and February 1974
caused major Burdekin River floods. These entered the Coral
Sea as freshwater plumes, carrying large quantities of
terrigenous sediment, which were turned northwards and
north-westwards by the prevailing south-east winds and waves
to subsequently reach the Cleveland Bay area. There was also
a more direct freshwater and sediment influx to the bay from
the smaller rivers flowing into it; about 458,700m3 of
sediment had to be removed by maintenance dredging from the
Platypus Channel following Cyclone 'Althea' and the
sUbsequent river floods. Developmental dredging to cut the
seaward dog-leg channel to the Platypus Channel and increase
the swing basin depth in the Harbour during the early and mid
1970's produced enormous quantities of dredge spoil. The
total annual dredging figures soared to a peak of over 2
million tonnes in 1973/74, which is equivalent to nearly
two-thirds of the Burdekin River's average washload plus
bedload of 3.45 mi 11 ion tonnes (Belperio, 1979). As much of
this dredged sediment appears to have been Holocene mud it is
likely to have been redistributed in the bay from the dump
sites, in response to tidal and wind-induced currents.
75
It therefore seems highly probable that most of the
seagrass was buried by the deposition of this huge quantity
of sediment delivered to Cleveland Bay both by natural
processes and from dredging. It may have contributed also to
the extensive death of mangroves, which took place along the
south-west coast of Magnetic Island, during the 6 years
following Cyclone 'Althea'. However from the aerial survey
evidence it was not possible to detect any changes to the
coral reefs, except in the seagrass growing in the sediment
on the extensive south-west Magnetic Island coral reef flat.
Future Assessment of the Effects of Dredging in Cleveland Bay
To assess the effects of dredging in the future, with
greater precision than has been possible in this
retrospective assessment, it is suggested that the following
monitoring and research programme is required:
1 Detailed recording of localities of dredging, amounts
and type of material dredged, and locality of dumping.
2 Observations of the movement of the dredge spoil plume
under different wind, wave and tidal conditions.
3 More detailed instrumental measurements of tides and
tidal currents throughout Cleveland Bay and West Channel
to provide an understanding of the circulation pattern,
and to resolve the apparent contradictions in the
earlier measurements obtained by different methods.
4 Establishlnent of a wind recording station to replace
that at Cape Cleveland, which closed in 1987. Continued
measurement of regional wind flow at a similar station
is important to link to wave records, and for
determining wind-induced water currents.
76
5 The wave recorders should be adapted or changed to
enable wave direction to be recorded, in addition to
wave height and wave period, as at present. Records
from both Townsville Port Authority wave recorders,
sited off Cape Cleveland and in Cleveland Bay, should be
analysed by the Beach Protection Authority, not only the
former as at present.
6 Monitoring of the various types of change discussed in
this report, should be undertaken at carefully selected
sites. Linked aerial and ground surveys would be
especially valuable. Analysis of these changes in the
light of varying wind, wave and tidal conditions, and
the dredging programme should enable its impact to be
assessed effectively.
77
REFERENCES
~A~d~m~i-,-r-,:a~lc..:t:oiYl--T~l-,-· d~e-,-T~a~b-,-l.::e~s, 198 7. Vol ume 3, 1988 Pac i f i cDc ea n
adjacent seas. Hydrographer of the Navy, Taunton UK.
and
Annual Reports of the Engineer of Harbour and Rivers on Works
(Queensland) 1876-1928, for years ending 30 June. No report
pUDlished for 1921; no reports located for years 1891-1901
incl usi ve.
Annual Reports of the Marine Department (Queensland)
1894-1933, for years ending 30 June. No report published for
1893, 1896 and 1921.
Annual Reports of the Queensland Department of Harbours and
Marine 1934-1987, for years ending 30 June.
8each Protection Authority, 1988. Wave data recording
programme, Townsville Region. Report No. W 03.2.
Belperio, A.P., 1978. An inner shelf sedimentation model for
the Townsville region, Great Barrier Reef province.
Unpublished Ph.D. thesis, James Cook University of North
Queensland, Townsville.
Belperio, A.P., 1979. The combined use of washload and bed
material load rating curves for the calculation of total
load: an example from the Burdekin River, Australia. Catena
6, 317-329.
Belperio, A.P., 1983. Late Quaternary sedimentation in the
Great Barrier Reef lagoon, pp71-76. In Baker, J.T. et al.
(eds. I, Proceedings of the Great Barrier Reef Conference,
Townsville 29 August - 2 September, 1983.
78
Carter, R.M. and Johnson, D.P., 1987. Post-glacial sediment
distribution in Cleveland Bay, Townsville. Report for
Townsville Harbour Board.
Coles, R.G., Lee Long, W.J., Squire, B.A., Squire, L.C. and
Bibby, J.M., 1987a. Distribution of seagrasses and
associated juvenile commercial penaeid prawns in
north-eastern Queensland waters. Australian Journal of
Marine and Freshwater Research 38, 103-119.
Coles, R., Mellors, J., Bibby, J. and Squire, B., 1987b.
Seagrass beds and juvenile prawn nursery grounds between
Bowen and Park Point. A report to the Great Barrier Reef
Marine Park Authority. Queensland Department of Primary
Industries, Information Series Q187021, Queensland
Government, Brisbane.
Collins, J., 1987. Fringing reefs of Magnetic Island, pp
44-49. In Baldwin, C.L. (Ed), Fringing Reef Workshop:
science, industry and management. Workshop Series No.9,
Great Barrier Reef Marine Park Authority.
Department of Harbours and Marine Queensland, 1986. Harbours
and Marine: port and harbour development in Queensland from
1824 to 1985.
Gill, A.M. and Tomlinson, P.R., 1969.
of red mangrove (Rhizophora mangle L.l
morphology. Biotropica 1, 1-9.
Studies in the growth
I. Habit and general
Lanyon, J., 1986.
Great Barrier Reef
Series, 3, 54pp.
Seagrasses of the Great Barrier Reef.
Marine Park Autnority, Special Publication
79
Lou r ens z, R. S ., 1977 . c-Tc-r-,-0LP--,i--,c--,aC-'l-----,c",y,--c,--l--,o,--ncce-,--,-s----,-i--,n----,-tc-h--,e----,-A,-,u,-,s--,tC-'rC-'a--,l--,l--,'a--,-n
region July 1909 to June 1975. Bureau of Meteorology,
CanlJerra, 111pp.
Mc I nty rea nd Ass 0 cia t es Pty . Ltd., 1974. P1ann i ng ,
environmental and development study, Townsville Harbour. Vol
2. Engineering and economics. For Townsville Harbour Board.
Oliver, J., 1978. The climatic environment of the Townsville
area, pp 3-17. In Hopley, D. (Ed), Geographical studies of
the Townsville area, Monograph Series, Occasional Paper 2,
Geography Department, James Cook University of North
Queens 1and, Townsvi 11 e.
Phillips, A.W.,
MorecamlJe Bay.
1968. A sea-bed drifter investigation in
The Dock and Harbour Authority. XLIX (571).
Phi 11 ips ,
Bay. The
A.W., 1969. Sea-bed water movements in Morecambe
Dock & Harbour Authority, XLIX (5BO).
Ph ill ips,
drifter.
Bulletin
A.W., 1970. The use of the Woodhead sea bed
British Geomorphological Research Group Technical
4, 29pp.
Pringle, A.W., 1983. Sand spit and bar development along
the East Burdekin Delta coast, Queensland, Australia.
Monograph Series No. 12, Department of Geography, James Cook
Un i ve r s i ty 0 f Nor t h Que ens 1and, Tow ns vill e . 34 PP .
Pringle, A.W., 1984. Evolution of the east Burdekin Delta
coast, Queensl and, Austral i a 1940-1980. Zei tschri ft FUr
Geomorphologie N.F. 28(2), 129-154.
Pringle, A.W., 1986. Causes and effects of changes in
fluvial sediment yield to the north-east Queensland coast,
Australia. Monograph Series, Occasional Paper 4, Department
of Geography, James Cook University of North Queensland,
Townsville.
80
Queensland Water Quality Council, undated c.1983. Report on
water quality monitoring, Cleveland Bay.
Report of the Portmaster on the Department of Ports and
Harbours of Queensland, 1882-1883.
Smith, A.S., 1974. Classification and distribution of
sediments on some north Queensland fringing reefs.
Unpublished M.A. thesis, Department of Geography, James Cook
University of North Queensland, Townsville.
Smith, A.S., 1978. Case study: Magnetic Island and its
fringing coral reefs, pp 59-64. In Hopley, D. (Ed),
Geographical studies of the Townsville area. Monograph
Series, Occasional Paper 2, Geography Department, James Cook
University of North Queensland, Townsville.
Spenceley, A.P., 1977. The geomorphological and zonational
development of mangrove swamps in the Townsville area, North
Queensland. Unpublished Ph.D. thesis, Department of
Geography, James Cook University of North Queensland,
Townsville.
Taylor, H.J., 1980. The history of Townsville Harbour
1864-1979. Boolarong Publications, Brisbane for Townsville
Harbour Board.
81
Attachment A
'APPENDIX l'
IWVIHONI18tI'l' PROTllCTION (SEn DU~pn'G) ACT 1901
GENERAL p!mMIT
:;:, Grilhiln1 l"re<leri.ck Richnrdaon, r-liniu'ccr of S·tate fOJ: tlle ;\rto;
sport, the Environment, Tourism Bnd Territories, having hud
regard to the matters referred to in Section 19 of the
.i':.0vir.9Jlm~..rl~-".~ote,~.~1..'~!~~i'lD':l.~!!p'ing) Act .19'§J. und pursuant to my
DOW(~rS u!lder the Act,
onc, grunt n generul pennit to tho Townsvills port
Authority, No 1 The Strund, Towns?111e, OLD, G810 and
Bny person contracted by them for the swnB purpoGc, fOJ:
i\ period of twelvc months commencing on the date of .
Approval, to load alld to dump up to 350,000 tonnes of
dredge spoil of the );ind specified in Clause 5 Of
Appendix 1 attached, arising from the dredging of
'.l'o\"I!lGvi.lle f1IHbour flnd 119pro<lclles, subject ·~o the terms
~Hlc1 cO:ldition8 ~Ihich I.H0 descr.ibed and 3pecified ill
0?ye t:_c1!. ;·;1 , .
~..
t
~ .;.
19 !l8
. .
.Li _
._,~-
• ..:..~"", ....c.",:,,_....;•....:..~~..... :.!...'l-'':'':J-<I''''''-.lj'''~.~·_~.~~'''''''';~'':-''::'-~::....u ......~ceJ• .o:.·I..:...o~.·.,,,y.:£.·.l.·.L::"~ __ :"-"· .
()-t A,.,..,.,.' .......~';'fj\-.~IO'f. grunt a general permit to tll", TO~lnslJll1e P01-'C
i. 'i\uthoriti', No 1 'fhe Strend, Townoville, QLD, 4810 an·:]
;; any person cOlltracted by them Eor the same'p~rpoBe, for
U a peri.od of thirty-six months c0rnmcncing on the date of.hi approval, to load 'and to dump up to 53,000 tonne:rof
'·iI dredC;Je fJpoil per annurn comprising uncontaminllted .)
iii S.i.J.tC1tJ.on materilll crnd spillagtl arising from smull-scale'
;:~ maintenance dredging J.n TOlmGvillC2 Barbour Qlld
~ l1pproaches, subject to the terms and conditions which
~~ are dCGcrJ.bed and-specified in ~~!1..9.LU. '
r.., £-~l.\)ljJ - 'J< ---
~
31 'J1
Da t(;(J .............•• ". f ••••• "
GRA[lMI RICH,\RDSON
Hinister of State for the Arts,
Sport, the Rilvironment, Tourism
I\n<.l 'i'L'rritories
82
1. It is a condition of this pe~mit that any requirementa
lawfully imposed by State Departments and agencies in areaa
under their jurisdiction relative to the dredging, transport
and handling of dredge apoil are met.
2. The period of the permit is for twelve months for the first
part dnd thirty-six months for the second part, both
c-;ommenc.tng Oil the date of signature.
3.
~.
,.
:> •
6 •
7.
flatters relating to operation of vcssels and handling of
dredge 3poil are to be to tho satisfaction of. both the
Queensland Department of Harbours and Marine an~.tha
Cor,ll,lonl·/eal th ·DEipartment of Trflnspor.t -lind_Communl.cationo_,.
Vessels used In the loading, carrying and dumping of the
dredge spoil are to·comply with all relevant provisions of
internntionHl conventlollS. .
In the case or PD~t one, the 1~rge-8c~le dredging operMtion;
the dredge spoil to be loaded and dumped comprises rni.;;tur00
of Gilt, fine sand and clav, and is to bo i'l acco~·c'ianc0 Nl\".11
those materials described In the permit eppllccttlon of 3
July 1987 and in information sUbaequeritly provided by the
applicant. If there is ~ny departure from this description,
~he Department'of the Arts, Spor~, the Environment, Tourimm
and '1'erritor1e3 (the Department) is to be consulteel
imrr;edi,~teJ.y·regarding possib19._ch,Jlnges In requlrefllentG.~r_i~r
}:o the loading. of sllch mater iu..L"" IIl __the .CelRe of_?art ':\10, t·
~he small-scale maintenance dredging operation; the-~p~~ri,l
ito oe loaded and dumped comprises uncontaminated siltation
material and spillage.
The material to be dis?osed of is to be derived from
dredging operations at Townsville Harbour and ~latypus
Channel a!_ indicated in the permit application. No other
ffiaterinl addTt:]orfaT to··tha'c·ret"t·red to 8bovl:l-is-.to_.b0.
loaded or dUlnped;
The total quantity of dredge spoil ~o be dumped under part
one of this permit is not to exceed 350,000 tonnes, ar~n.9.­
from approximately 200,000 cubic metres of mC\ter1al.· ·~The
total quantity of dredge Gpoil under part two ~f thiG permit
is not to exceed 53,000 tonnes per annum, arising from
approximately 30,000 CUbic metres or uncontaminated
R i 1til t i Oil Illi\ t c r i l\ 1.
83
- 2-
8. Dumping of all dredge spoil llnd wI.Ishi.ng of veGsel" in pllL-t
one of the permit i6 to take place within Q four-sided
figure whoee cornero ar~ Bituated ntr
19'10'39" 5 146'54'53" £
19'08'09" S 146·56'29" B
19'08'43" s 1·16'57'2:3" E
19·11 ' 1 3 n S "1<36'55'51" r.
9. Du~pin9 of all dredgc spoil and washing of veRBals in.p~rt
.:,;,\,;o·cor the 9crmit. .is to take place within F.l foul'·-i3.\<'led
figure whose cornero are situated &t:
19°13'.18" S 146°52'00" E
19°14'51" 5 1~6054'OO" }3
19°15'54" 5 146°53'18" E
19°14'45" S 1~605'iI22" "'~
1(), No later than seven dnyo pi'ior'-t() '.:h;;> COllmH?nc:~men·t of
lo~dil)g and dumping of the dredged mftterial, the followin0
information concerning tho carrier(s) of the matorinl La to
be provided to T~e Secretory, Department of the ArtB, Sport,
tllB Environment, tourism and Territories, GPO ~O~ 707,
Canberra, ACT 2601 (the Secretary)
name(s) of vessel(!)i
name(s) and address(esj 0;: O\'iilC:(S) ot ',-esGel(s),
name(s) 'and add,ess(e3)' of ifli\f;'.:er(B) ·of v\'ssel(s) i
port(s) of registration;
type(s) nf vessel(s);
expected date of commence~ent of loadin9! and
expected frequency of dumping and tmoullte (eg per
cJuy/weck) .
11, The Department is to be advised promptly of any varictlon of
the information provided in Clause 10 above.
,;
1 "
12. All costs incurred as a result of specified monitor5.ng
activity and analysis of samples are to be met by TPA,
-- - -.# .•---••--.- .---- .• - - - • . I,
13 .f·:>xc<ml·~~t·i·o!)::':oLthe_c1r.e~tge._an(Ld~~p;n~ ve~~el log book .
.... entries, and verification that dumi'ing is 'takTng- pYuc':"8'i n 'iT:
". tile cocrcct locilt.f.OJ1, is to be th'e responsibility oF. '£PA.,i'l
.~~ /141/co~~-~~~:'~~-~UperVil)ion' of ali·actilJjt.tes~·s~;c·i.Il-ted··;~i-; the
, operation is to be undertaken by TPA, Which is to advioc the
Secretary immediately of any unscheduled nnd environmentally
adverBS Avent. '
15. The monitoring programs in Annex II nre to be UJ1~ertnkcn for
th0 Inrge-~cRle SHa dumping event of part one of tIle permit
IIn(l tho,,,! SpCCl fled in. Annex B undertaken f:or tile mOllll-,
scale sea dumpirlg eve .. l,s of part two of the pOI·mit.
84
-3-
Certified copics of dumping vessels' log book entries
covering nll loading nnd dumping activities are to be
submitted monthly to the Secretary. The details recorded
should include:
time (lnd date;
quantities dumped; find
actual location at the commencement of each dumping
operation (lntitude and longtitude).
17. Discharge of material at the dumpsite is to be managed so
that, ilS far as prac·ticable, Gpoil _is dietdbut.e<1 evenl:,
over, Bnd not beyond, the area of the site.
lB. If at any time U developing risk is identified from dredging·
and dumping operations, measures are to be tak~rtimmediately
to mitigate 8L\ch risl" including· r.e:,trict.ions on t.ime and·
locLltion of aDorations, The Department is to~- be--advised
immed.i.lltely of any SllCh s:l·fu:-at-ion;-c-·
19. Any additional monitoring, inveitigBtion or in9pectio~ which
may be required in po~nection with this operation by the
Depart.rnel1t, including a1 rand/or surfa.ce surveillance ar,,:l
the provision of f~ci1ities rnent:i.cned in cla!!sQs 21 and :~2
below shall be at the cost of TPA.
20. At the completion of the dredging operation tho foll~Jing
information is to be provided to·~he Secretar~:
dates of commencement and completion;
total quanti~y of dredge 8poil handled, in metric tonnem;
and
the leafl.t depth of ';Iater O'le'.- th" dredge gpoil dumping
site determined by sounding and -expresfJed-".,-ith reference
to chart.datum.
21. If so required, up to tNO COnyT:onwealth Government nomirieec
are to be afforded access to witness, inspect or examin~ any
part of the operations, including any monitorln,g activIty or
equipment, ~nd ~re to be providad with Rny necessary _. _ ..
. assistance_in.CiHryJJ.~g_Q.ll..t:-.tl'~)J __dlJ'::leso The Permittee 1s
to meet all costs for thcll.tt.endan-cEiof Comnlo-nwellTth ~---...
Government nominees inCluding their travel, accommOdation
and associated incider.tal expenses.
22. If the duties specified in clause 21 require the
Commonwealth Government nominees referred to above to go to
sea, the permittee is to provide them I'lith food and
accommodation of an acceptable standard incidental to the
carryin9 out of the duties specified. Arrangements are to
be made for nomInees 011 complet.ion of the operat.i06 to be
returned to a convenient Australian port.
85
23. If meA6ures are taken to mitigate any developing rieks Under
alauao 10, n report 1s to be made immediately to the
Department detailing such situations, meaoGres adopted end
oUboequent monitoring proposalS.
24. ·Uncontaminated" in this permit and appendix shall have the
meaning of not more contaminated that the material described
in clnuse 5 of Appendix I.
25. TPn io to ensure that all owncro ana persons in ch~rge of
vessels involved in the dredging, loading an6 dumping of
dredge apoil src fUlly conversant with the requirements of
this permit. and of the Environment Protection i Ge!l D'JiTiPiilCj)Act 1981. --_._-_._.._-_..~-'- ..
86
MONITORING REQUIREMENTS POR THg DUMPING OP DREDGE SPOIL PRO~
TOWNSVILLE MARB6o~D J?LM'YFOS CHANNEL
PllfpoBe
The TPA intends to dump a portion of the drodge spoil obtained
from Townsville Barbour on land after July 1989. The general
?urpose of this monitoring progri1ffi is to find," BLLltable dump
site for that portion of dredge spoil which will cont!!IUe t6 be
clumped ~t ~~en.
spe:!.ricillly this monitorIng progri1ffi is to:
de'c,,,,rnine whether the dumping of dredge spoil inte,fercCl
with marine ecosy9tems and, if so, whether tile intarfe~ence
13 unacccrtablc;
obtain a- better unc1e,standin0 of tbo circulai:!.oi,- in
Cleveland Day and determine whether thore is B BUi~Bb12
alternative dump site in Cleveland Bay which has less effect
on Platypus Ch8~nel Bnd Magnetic Island beaches and reefal
and
determine a suitable dump site out8ide-Cleval~nd Bay shoula
there be no suitable dump site within Cleveland Bay for
large-scale dredge spoil fI.'0',1 'l'O\in8i1~11e Barbour dreo,!ii,g.
!<equi rements
At UIC commencement of. the permitted operation, the time tai"Jn
for the plumes of dumped spoil-to 9Qttle or disperoe ~t the
dumps! te is to be recorded aDd the movement of.plum1'rs~u"der the
full range of the tidal and current conditions is to be observed
by ~ nominee of the -GBRMPA, who shall report on an~ actunl or
potential hazard to neighbo~ring~reefs or areaB of ecologfbal
Iimportance.
The Townsville Port Authority 8h~ll, in consultatton with th~
Great Barrier Reef Marine Park Autho=ity, the Jame. Cook
Uilive-rs i'ty "and-tlfe-AueftTalT,OlIhstl tlli:':e -6f-Mli-rth-e-Sc"i-(fl)C0,
develop and carry out 1\ monitor_i_ng p!."ogram acceptubleto the
Deportment of the Arts, Sport, the Environment, Tourism Bnd
'rerritories Hhich incllldes the follmdng component.s:
hydrodynamic studies of tile circulation in Cleveland Bay, to
the extent necessary to verify the suitability of the
dumpsite or of an alternative a'lmpsitc. such studies may
include mOdelling;
87
-2-
watcr qu~lity studics at the dumpsite and in arens of
ecological significance to the extent necessary to verify the
Gultubility of the dumping p.~ccice3 adopted; and
investigation nnd recording of neighbouring 8cn3itivcoarc8s,
including the reefo fringing Mugnetic Islnnd und sea grass beda
in Cleveland Day.
~crort~ O~ the above are to be provided to DASETT at s!;c m;nthly
5.:: tc l"lJi), 1 r,; 0
88
AHllffiX D
MONITORING REQUIREMENTS FOR TRE DUMPING OF CRECGH SPOIL FROM
tmll.u..-SCALE AAINTBMANCg DRIlDGING OPER_>fTioN8 IN 'L'OIffiSVILLB 1Jh'..RBOOR_____ ,0 _ •• _
Part t~o of this permit refero to the occasional dumping or 3mDll
g~antit!es of ·uncontaminated ~iltat!on material or spillage .
deriv~d from maintenance dredging in Townsville Harbour. Ie ie
undor3tood that no contaminated material is to be 11Rlldlad in thio
t:;;.1 y .
Discharge within th2 designated dumpside ~or thi6 material is to
be 6C art'~nqed tl\at. as nearly ao practicable. the ~ateri~l i~
diutributed"evenly ~pon a BUbstrat~m of simil~r nature nnd
9 racHng.
Ii! collnboft:\tlon \I/.tth the GBRf1PJ.\, meafHlt"~~~} are to ;)n t.aka!'! ,:n
av/)id intn1.:ferenc0 ~lit::.h (llJgong liilb(tat.n- 0.i:O ~·:::-c:!.vii.:i.eG- 3~1~ ;tat:0r.s
ac1jnccni: to the clumping. arc!I.
89
TABLES
90
TABlE 1
Dredged lJepths at Port of Ta.vnsville 1884-1987(1retres belCM L\;oST}
Year
ending
?/J/6
Outer Harbour
Pla~s SWing
Channel Basin
Berths
Inner Harbour - Ross Creek
Channel Swi ng Berths
Basin
Dredge
1884
1005
1886
1007
188!l
1889
189J
3.7
3.7
3.0
4.6
Pla1;ypus
"
1.1 "
"
Octopus
"
"
1891
189'Z 5.5
1893 5.5
1894 3.5 4.0
1895 3.8 4.0 6.7 2.1
1896
1897 3.4 3.8 5.9 2.0
1898 4.6 3.4 5.5-5.8 1.8
1899 4.6 4.6 5.2-7.9
19JO 4.6 6.7
-----------------------------------------------------------------------------------------------------------_..
1901 4.1 6.4-7.3 "
1!XJ2 4.4 6.4-7.3 1.8 Octopus
& Crocodile
1903 4.8 6.4-7.3 1.8 "
19J4 5.2 4.6 7.0-7.3 1.5-2.4 "
1905 4.8 4.3 7.0 2.4 1.8-3.0 "
19-Xi 4.9 5.2 6.4-7.0 1.8-2.1 "
1907 4.7 5.3 7.5 2.3 "
1~ 4.7 5.1 6.7-7.0 2.3 "
1909 5.2 7.0-7.3 4.6 "
1910 4.6 6.7-7.6 3.0 3.0-4.6 "
-----------------------------------------------------------------------------------------------------------_..
1911 5.2 7.3-7.6 3.7 2.6-4.3 "
1912 5.0 5.0 6.9-7.2 3.0 2.7-4.3 Cleveland Ba,y
1913 5.5 5.7 6.7-7.6 3.4 2.7 2.6-4.3 "
1914 5.5 5.3 6.7-7.6 2.7 2.6 2.4-4.0 Cleveland Ba,y
& Crocodile
1915 6.4 6.1 7.9-8.5 2.7 2.7-4.0 "
1<J16 6.4 6.4-7.3 7.9 2.6 5.5 "
1917 6.7 6.7 7.6-7.9 3.0 5.2 "
1918 6.7 7.3 7.6-8.2 2.9 2.9 5.0 "
1919 5.8-6.7 6.7 7.6-8.5 2.<J 4.9-5.5 "
1920 6.7 7.8-8.5 2.9 3.4-4.6 Cleveland Ba,y
-----------------------------------------------------------------------------------------------------------_..
91
TABlE 1 conti rued
Year Outer Harbour Inner Harbour - Ross Creek Dredgl
ending Pla1(ypus SWlng Berths Channel SWlng Berths
JJ/6 Channel Basin Basin
Igzl
Igz2 6.7 7.0 7.6-7.9 2.4 2.4 4.3-5.2
m3 6.1 7.0 7.6-7.9 2.4 2.4 4.3-5.2
I!TL4 6.1 7.3 8.2 2.3 2.4 4.3-4.6
1925 6.7 7.3 7.0-8.2 2.0 2.0 2.7-3.7
Igz6 6.7 7.3 6.7-8.2 1.8 1.8 2.7-3.7
1927 6.7 7.0 6.7-8.2 1.8 1.8 2.7-5.5 Cl eve1and Ba,y
Igz(l 6.4 6.1-7.9 2.1 0.9-4.6
Igz9
1930
---------------------------------------------------------------------------------------------------------------
1931
1932
1933
1934 7.0 7.3 7.9 Cleveland Ba,y
1935 6.7 7.0 8.2 1.7 1.8 0.6-4.3
1936 6.7 7.0 7.9 4.0 1.1-4.9
1937 6.7 7.6 7.9-8.5 4.0
1938 6.7 7.0 5.8-8.5 3.8 4.0 3.0
1939 6.7 7.0 7.5-8.5 4.0 4.0 1.4-4.1
1940 6.7 6.9 6.6-8.5 3.7 4.0 1. 4-4.3
-------------------------------------------------------------------------------------------------------------_.
1941 6.7 6.7 6.1-8.5 3.7 4.0 4.6 Cleveland Ba,y
&Trini1(y Ba,y
1942 7.2 6.1 6.1-9.8 2.7 4.0 4.6 Cleveland Ba,y
Trini1(y Ba,y &
Pl a1(}'puS II
1943 7.5 6.6 6.1-8.8 2.7 4.1 3.7-4.3
1944 7.3 6.9 6.1-8.5 2.9 4.0 3.7-4.3 tIono.ong
194ti 6.7 7.0 4.7-8.8 3.2 3.8 3.4-3.8 Cleveland Ba,y
1946 6.1 7.0 7.5-8.5 2.1 2.1 2.1 Cleveland Ba,y
1947 6.6 7.0 6.2-8.5 2.1 2.1 2.1 tIono.ong &
Trini1(y Ba,y
1948 5.9 7.0 6.1-9.4 2.1 2.1 2.1 Cleveland Ba,y &
Trini1(y Ba,y
1949 6.4 6.6 5.6-8.5 3.0 2.0 2.0-2.1 Cleveland Ba,y
1950 5.9 5.8 ti.8-8.5 3.0 2.0 2.0-4.0 "
-------------------------------------------------------------------------------------------.------------------
1951 6.1 6.1 7.ll-7.8 3.0 1.8 1. 5-4.0 "
1952 6.4 6.1 6.7-9.4 3.0 1.8 1.5-4.0 "
1953 7.0 7.0 6.7-8.7 3.0 1.8 1. 5-4. U Cleveland Ba,y &
TMlsville
1%4 7.0 6.4 5.9-9.1 "
1955 7.0 7.0 6.1-8.8 2.4 2.4 1.8-3.4 "
1956 7.2 7.3 4.9-8.5 2.4 2.4 3.4 "
1957 7.2 7.3 8.5-8.8 2.4 2.4 2.4 "
1958 7.0 7.3 8.7-9.1 2.4 2.4 3.4 "
1959 7.2 7.5 8.5-9.1 2.4 2.4 3.4 Cleveland Ba,y &
Pl a1(ypus II
1960 7.3 7.3 7.9-9.1 2.4 2.4 Cleveland Ba,y
&TMlsville
-----------------------------------------------------------------------------------------------------------_..
92
TABLE 1 continued
Year Outer Harbour Inner Harbour - Ross Creek Dredge
ending Pla1(ypus SWlng Berths Channel SWlng Berths
30/6 Channel Basin Basin
1961 7.6 7.2 8.8-9.3 Cleveland ~ &
TO'nIlsvill e
1962 7.5 7.6 8.2-9.1 "
1963 7.6 7.9 8.7-9.4 "
1964 7.9 7.9 8.4-9.8 "
1965 7.8 7.9 7.5-10.0 3.4 3.4 Cleveland ~
TO'nIlsvill e &
f/ourilyan
1966 7.8 7.8 7.8-9.8 3.4 3.4 TO'nIlsvill e
1%7 7.9 7.9 7.8-9.9 3.0 3.0 "
1968 8.5 8.5 9.1-10.2 "
1969 8.5 8.5 8.8-9.8 "
1970 8.5 8.5 7.5-10.0 "
---------------------------------------------------------------------------------------------------------------,
1971 8.5 8.6 8.2-10.0 "
Ross River
Entrance
Channel
1972 8.8 8.5 8.4-10.6 3.7 "
1973 9.0 8.7 8.3-10.8 "
1974 9.0 8.6 8.0-11. 7 Sir Thanas Hiley
& Townsville
1975 9.9 8.7 7.5-11.7 "
1976 10.7 8.6 7.7-12.0 "
1977 10.6 9.0 7.2-12.3 TO'nIlsvill e
1978 10.7 9.0 7.0-12.3 "
1979 10.8 9.4 7.2-12.0 "
1980 10.7 9.4 7.2-12.3 "
--------------------------------------------------------------------------------------------------------------_.
1~1 11.0 9.5 8.0-11.6 "
1982 11.0 9.5 8.1-11.6 "
1~ 11. 9 10.4 7.4-11.2 2.1 TCInIlsville &
Sir Thanas Hiley
1984 10.4 10.4 7.3-11.2 1.3 Sir Thanas Hiley
1~5 lU.9 lU.5 7.2-11.0 2.2 "
1~ 10.7 10.5 7.2-11.4 2.2 "
1~7 10.7 10.5 7.2-11.4 2.5 "
Sources:
1 Annual reports of En9ineer of Harbour & Rivers on Works (Queensland) 1876-1928 (with gaps - see References).
2 Annual Reports of the Marine Departmmt (Queensland) 1®'l-1933 (except 1921).
3 Annual Reports of Queensland Departrrent of Harbours & Mari ne 1934-1987.
Note: In early data, especially before 1925, sore discrepancies occur between dredging figures in different
reports for sarre year; also variation in description of locali1(y within harbour between different reports &
years.
93
TABlE 2
All Dredging Records for Port of TOi/TlSville 1889-1965 and for 'Sir Thanas Hiley' 1974-1976
Year endi ng JJ/6 Quanti 1(y Dredged Notes Dredge
1009 93,620 cu yards Octopus
1891 67,900 " " Octopus
Total to 1891 547,423 " "
1892 133,595 " " Sandstone & tenacious clqy & ITlJd Octopus & Plant
for 12 IOOnths
1893 203,966 " Mud, clqy & sandstone Octopus
1894 112,830 " Mud, clqy & sandstone Octopus
1895 207,410 " Mud, clqy (sore stiff) & sandstone Octopus
1896 149,725 " Mud, c1qy & sandstone Octopus in 8 rronths
1897 145,~ " Mud, clqy and standstone Octopus in 5.5 "
1900 656,UXJ " Octopus and
Crocodile
1941 533,626 cu yards Cleveland 8qy &
Trini1(y 8qy
1942 425,000 barge tons All ied Works Council Schare for Trini1(y 8qy
TO\;I1svill e Harbour iflllrovarent
287,<xXJ " " " Morwong
395,6OO " " " Fitzroy
61,450 " " " Pla1(ypus II
40,650 " " " Cleveland 8qy
6,000 " " " G.F.H.
26!3,axJ tons Mai ntenance dredgi ng in Pl a1(ypus Channel Trini1(y 8qy
11-12/1943 135,lXXl barge yards From Pla1(ypus Channel & Outer Harbour Morwong
1945 155,318 " " From Platypus Channel & Harbour Cleveland 8qy
8-11/1946 349,<XXJ " " From Pla1(ypus Channel & Harbour Morwong (also
Tri ni1(y Bqy - no
date)
1949 450,<XXJ " " From Pla1(ypus Channel & Berths Cleveland 8qy
1950 420,LOO " " From Platypus Channel, Swing Basin & Berths Cleveland 8qy
1954 177,760 " " " " " Cleveland 8qy
1,02O,axJ " " " " " TOi/TlSville
195U 222,605 yards " " " Cleveland 8qy
872,axJ " " " " TO\;I1svill e
195~ 154,970 barge yards No 2 Pier Pla1(ypus II (also
Cleveland 8qy and
TO\;I1sville-no data)
1960 199,915 barge yards Mainly developrental dredging Cleveland 8qy
830,axJ " Maintenance dreding To,omsv ill e
1962 205,434 " Developrental dredging Cleveland 8qy
fu9,OOO " Maintenance dred9in9 TO\;I1sV ill e
1963 63,620 " Developrental dredging - Suter Pier Cleveland 8qy
813,axJ " Maintenance dredging TO\;I1sville
1%4 129,664 " Developrental dredging - mainly tanker berth Cleveland 8qy
1, 134,LOO " Maintenance dredging TO\;I1sville
50,910 " Ross Creek boat harbour - developrental dredging Mourilyan
1965 77 ,826 cu yards Developrental dredging - tanker berth Cleveland 8qy
1,074,000 hopper yards Mai ntenance dredgi ng TO\;I1svill e
60,860 barge yards Developll=ntal dredging - Ross Creek boat basin
and berths Mourilyan
94
TABLE 2 continued
Year ending 30/6 Quantit;y Dredged Notes
1974 1,510,700 tonnes (dry) Developrental dredging in Plat;ypus Channel
and Swi ng Basin
1975 1,006,890 tonnes (dry) Dredging Plat;ypus Channel Fran Beacon 7 to
harbour entrance and drag1i ne dredgi ng
of Ross Creel<
1976 316,030 tonnes (dry) Developrental dredging in Plat;ypus Channel
and several berths
Dredge
Sir Thanas Hiley
Sir Thanas Hiley
Sir Thanas Hiley
Sources:
1 Annual Reports of Engineer of Harbours & Rivers on Works (Queensland) 1876-1928 (with gaps see References)
2 Annual Reports of the Marine Departnent (Queensland) 1894-1933 (except 1921)
3 Annual Report of Queensland Departrrent of Harbours & Marine 1934-1987
95
TABlE 3
Townsville Port Authorit,y t"onthly Dredging Records (tonnes) for S.D. 'Townsville'
Date Plat,ypus ~ing Berths Total Notes
Channel Basin
1965 July no records no records no records no records
Aug no records no records no records no records
Sept 3,271 2,538 5,809
OCt 24,293 1,225 &l 25,6(Xj
Nov 1,574 1,574
Dec
1966 Jan
Feb 5,741 299 464 6,tn4
Mar 2,598 8,176 6,262 17,036
Apr 10,426 10,426
Mqy 8,933 10,163 6,154 25,250
June 23,515 1,~ 1,ffi7 27,387
Total 1%5/ti 69,9'<!5 34,812 14,855 119,592
-------------------------------------------------------------------------------------------------------------_.
1966 July 26,639 llO 856 27,605
AU9 1tJ,375 4,545 697 23,617
Sept 17,7fIJ 2,806 1,469 22,035
Oct 19,234 1,749 1,413 22,396
Nov 27,392 1,990 29,382
Dec 9,448 105 9,553
1967 Jan 13,038 1,173 285 14,496
Feb 12,073 3,691 1,122 16,886
Mar 2U,019 4,515 929 25,463
Apr
Mqy
June 35,140 1,496 213 36,849
Tota1 1966/67 199,1l8 22,180 6,984 228,282
--------------------------------------------------------------------------------------------------------------
1967 July 14,125 2,765 1,566 18,456
Aug 26,636 1,600 28,236
Sept 28,1~ 2,056 3,())5 33,311
Oct 16,455 3,773 821 21,0l9
Nov 18,730 1,520 1,723 21,973
Dec 12,214 2,550 2,698 17,462
1968 Jan 1,567 329 254 2,150
Feb 12,413 3,302 2,938 18,653
Mar 24,770 3,174 27,944
Apr 6,407 9,784 1,882 18,073
Mqy 13,889 10,577 1,532 25,998
June 6,996 1l,946 1,109 20,051
Total 1967/68 182,392 53,376 17,5&l 253,356
-----------------------------------------------------------------.--------------------------------------------
96
TABLE 3 continued
TOfmsville Port Authori1;y tIonthly Dredging Records (tonnes) for S.O.'TOfmsville'
Date Pla1;ypus ~in9 Berths Total Notes
Channel Basin
1968 July
AU9 16,851 347 890 18,aJ8
sept 15,829 6,901 3,225 25,955 6,416 pllJll€d into boat
raIfll reclanl:ltion
OCt 26,186 0,614 211 33,011 17,126 " "
Nov 20,570 6,443 27,013 17,968 " "
Dec 15,953 1,174 17,127 14,514 " "
1%9 Jan
Feb 17,247 5,767 1,784 24,798
Mar 27,757 3,670 31,427
Apr 34,517 34,517
Ma,y 28,952 1,876 30,828
June 20,873 6,450 7,238 34,561
Total 1968/69 224,735 39,242 13,348 277,325 56,920 " "
---------------------------------------------------------------------------------.__.----------------------------
1%9 July 10,755 21,592 843 33,190
AU9 34,644 2,957 37,601
sept 13,799 297 931 15,027
OCt 19,<)93 4,251 24,244
Nov 38,261 2,0'12 40,303
Dec 13,210 721 13,931
1970 Jan 4,789 6,344 9,475 20,608
Feb 20,489 6,490 6,005 33,064
Mar 30,328 4,328 1,107 35,763
Apr 21,003 10,036 2,776 33,815
Ma,y 32,545 530 33,075
June 19,564 19,564
Total 1%9/70 259,13ll 59,588 21,217 340,185
-----------------------------------------------------------------------------------------------------------------
1970 July 6,194 1,'-85 6,293 14,472
Aug 20,980 1,983 1ll,640 33,603
5ept 25,359 4,767 6,828 36,954
OCt 13,036 18,788 3,853 35,677
Nov 729 22,829 9,032 32,590
Dec 9,374 17,072 1,770 28,216
1971 Jan 9,224 15,~ 7,997 33,125
Feb 260 33,065 33,325
Mar 7,939 15,911 5,330 29,100
Apr 13,620 5,425 6,588 25,633
Ma,y 23,282 5,052 3,858 32,192
June 9,IHJ 5,198 11,173 25,489
Total 1970/71 139,115 147,979 73,362 360,456
----------------------------------------._--------------------------------------------------.--------------------
97
TABLE 3 continued
TOnTlsville Port Authorit,y MJnthly Dredging Records (tonnes) for S.D. 'TOnTlsvi11 e'
Date Platypus Swing Berths Total Notes
Channel Basin
1971 July 3,115 3,993 7,100
Aug
Sept 31,647 3,113 34,760
OCt 15,207 22,0'15 492 37,744
Nov 11,209 23,256 gol 35,416
Dec 15,1lX:i 17,936 33,042
1972 Jan 20,249 9,531 1,993 31,773
Feb 29,!iU'L 3,601 33,103
Mar 38,730 1,002 421 40,153
Apr 49,589 1,H15 408 51,182
Ma.Y 57,677 3,942 61,619
June 52,995 1,561 1,012 55,068
Tota1 1971/72 321,911 90,2!!7 9,270 421,46!l
-------------------------------------------------------------------------------------------------------------_.
1972 July 66,022 583 66,605
Aug 14,257 585 14,!l42
Sept 36,430 36,430
OCt 118,476 118,476
Nov 57,813 19,131 76,944
Dec 13,b7!! 14,542 2!l,120
1973 Jan 91,280 91,280
Feb 88,553 325 88,878
Mar 55,494 10,944 5,642 72,000
Apr 19,1ll 19,1ll
Ma.Y 29,474 726 30,200
June
Total 1972(73 541,903 80,098 21,235 643,236
--------------------------------------------------------------------------------------------------------------,
1973 July
Aug j2,1~ 32,180
Sept 67,853 67,853
OCt 79,656 79,656
Nov 25,575 5ti6 37,281 63,422
Dec 16,292 23,359 39,651
1974 Jan 32,822 6,984 39,806
Feb 49,310 5,441 7,647 62,398
Mar 25,402 7,814 33,216
Apr 25,867 6,235 1,ll5 33,487
Ma.Y 43,688 14,668 12,986 71,342
June 64,!!55 4,809 9,504 79,168
Total 1973/74 463,500 39,533 99,146 602,179
98
TABlE 3 continued
TCMIlsville Port Authori1;y ttonthly Dredging Records (tonnes) S.D.' TCMIlsville'
Date Pla1;ypus Swing Berths Total Notes
Channel Basin
1974 July 64,335 5,640 747 70,722
Aug 69,533 557 70,000
Sept 38,668 6,824 5,225 50,717
Oct 34,363 1,694 1,977 38,034
Nov 36,205 3,623 562 40,390
Dec 1,9'l4 18,1~ 20,122
1975 Jan
Feb 4,575 9,751 14,326
Mar 17,~ 2,778 4,175 24,939
Apr 13,672 9,370 23,042
~Iqy 25,104 2,039 27,143
June 15,105 365 11,132 26,602
Tota1 1974/75 321,470 31,232 53,425 406,127
---~-------------------------------------------------- -----------------------------------------------------------
1975 July 20,743 2,687 4,628 28,058
AU9 16,371 423 16,794
Sept
Oct
Nov 3,841 818 4,659
Dec 21,793 678 22,471
1976 Jan 15,709 15,446 3,347 34,502
Feb 9,003 21,848 2,420 33,351
Mar 12,103 39,144 879 52,126
Apr 954 24,416 6,%6 32,336
Ma,y 23,760 17,325 9,596 50,681
June 640 20,117 19,723 40,486
Total 1975/76 99,369 167,040 49,055 315,464
-----------------------------------------------------------------------------------------------------------------
1976 July 37,694 1,714 39,400
AU9 8,214 38,600 4,833 51,655
Sept 39,715 4,287 44,002
Oct 1,231 27,769 29,000
Nov
Dec 10,562 26,002 36,564
1977 Jan 12,587 25,226 37,813
Feb 44,038 21,0.J4 65,132
Mar 45,766 27,719 3,326 76,811
Apr 34,397 12,665 7,196 54,258
Ma,y 42,861 20,~7 5,735 69,583
June 24,199 30,005 4,961 59,165
Total 1976/77 223,855 307,4ti4 32,052 563,391
------------------------------------------------------------------------------------------------------------ ----~
99
TABLE 3 continued
T<Jn'l1sville Port Authorit,y t1Jnthly Dred9in9 Records (tonnesl S.D. 'T<Jn'l1sville'
Date Pla~pus Swing Berths Total
Channel Basin
1977 July 1O,1l93 27,313 2,176 40,382
Aug
Sept
Oct 4,016 21,873 2,397 28,286
Nov 1,839 52,974 54,813
Dec 16,407 33,421 3,242 53,070
1978 Jan 43,033 14,392 2,300 59,725
Feb 44,406 21,872 66,278
Mar 43,889 15,919 7,537 67,345
Apr 18,099 26,404 9,044 53,547
May 1,573 37,760 13,810 53,143
June 20,388 25,022 12,739 58,149
Tota1 1977(78 204,543 276,950 53,245 534,738
------------------------------------------------------------------------------------------------------------_..
19713 July
AU9
Sept 15,851 27,321 9,059 52,231
Oct 9,403 34,545 ll,023 54,971
Nov 26,977 35,034 5,937 67,948
Dec ll,531 18,763 9,451 39,745
1979 Jan 50,129 12,930 4,726 67,785
Feb 41,543 14,789 5,7913 62,130
Mar 53,860 1l,759 9,864 75,483
Apr 36,441 13,422 7,289 57,152
May 29,829 24,877 19,401 74,107
June UI,699 26,565 7,234 52,498
Total 1978/79 294,263 220,005 89,782 604,050
------------------------------------------------------------------------------------------------------------_.-
Date Pla~pus Swin9 Berths Ross River Total
Channel Basin Channel
1979 July 45,344 5,457 14,242 65,043
AU9 64,525 2,121 66,646
Sept
Oct 26,915 668 8,565 36,148
Nov 38,139 2,563 10,875 51,577
Dec 23,705 3,193 10,422 37,320
l~Jan 36,967 3,242 1,287 1l,497 52,993
Feb 11,966 1l,719 8,638 14,081 46,404
Mar 26,548 1l,878 2,687 4,921 46,034
Apr 41,757 6,545 48,302
May 36,580 3,360 . 6,390 46,330
June 84,784 84,784
Total 1979/80 437,230 42,869 47,565 53,917 581,581
---------------------------------------------------------------------------------------------------------------
100
TABLE 3 continued
TCI.'II'lsvill e Port Authori 1;>' Dredgi ng Records (tonnes) for S. D. 'TCI.'II'lsville I
Date Pla1(ypus Swing Berths Ross River Total
Channel Basin Channel
1'llO July 95,935 95,935
Aug 8,935 58,326 992 68,253
Sept 38,636 18,518 2,188 4,6lJ 63,972
OCt
Nov 19,942 8,324 5,6118 33,914
Dec 35,831 9,493 5,242 50,566
1~1 Jan 20,382 16,327 1,528 10,867 49,104
Feb 27,972 11,230 623 12,094 51,919
Mar 35,073 12,326 595 11,831 59,825
Apr 21,815 10,323 6,968 7,353 46,459
~ 13,317 20,129 11,162 1,an 45,689
June 18,959 22,152 4,826 45,937
Total 1980181 330,797 187,148 27,890 59,738 611,573
--------------------------------_.--.--------------------------------------------------.---------.----------------
1~1 July 9,650 14,025 10,354 34,029
Aug
Sept
Oct
Nov 7,324 45,020 5,750 58,094
Dec 8,533 27,lm 7,550 43,886
1~ Jan 10,493 21,154 13,948 45,595
Feb 3,161 24,402 710 10,527 38,800
Mar 18,016 17,305 6,345 13,769 55,435
Apr 12,451 13,945 3,925 11,340 41,661
~ 13,115 15,801 552 7,lUl 36,576
June 21,102 7,214 2,563 30,879
Total 1981;132 103,845 186,669 21,886 72,555 384,955
----------------------.-------------------------------------------------------------------------------------------
1982 July
Aug 31,832 8,~ 966 41,781
Sept 35,219 12,645 1l,073 4,399 60,336
OCt 47,468 9,468 8,357 65,293
Nov 35,7j5 5,535 559 12,038 53,867
Dec 31,(00 4,559 2,670 4,061 42,37U
1983 Jan 33,124 4,697 1,37ti 39,199
Feb 8,580 17,526 4,553 13,754 44,413
Mar End of dredging by 'S.D. Townsville'
Apr
t4J,y
June
Total 1982/83 223,038 63,413 18,199 42,609 347,259
Notes: 1 Fran July 1983 dredging for a feN weeks each year by Trailer Suction Dredge 'Sir Thanas Hiley'.
2 Although no written records have been found, it is believed that the dredged material in this table was
dLJ1\lE!d in the shallow draft dunp site (Figure ll, except for that obtained during the dredging of the
Sea Channel in the early to mid 1970's, which was dLJlped in the deep draft dunp site.
101
TABLE 4
TCIfIIlsville Port Authorit;y Dredging Records 1983-88 for T.S.D. 'Sir Thares Hiley'
~ solids (tonnes)
1983 12 - 16 July 5,920
14 - 18 August 63,340
109,260
1984 7 - 22 August 224,1~
11 - 13 Septelter 35,200
259,m
1<JJ5 12 - 17 June 87,05IJ
1<JJ6 8 - 23 July 221,(Xi()
16 - 18 August 41,<XXJ
262,UiU
1<JJ7 18 - 20 April 36,240
18 July - 1 August 216,110
252,350
1988 17 June - 2 July 164,600 (i nc1udi ng 62,780 tonnes
<!eve1oprenta1 dredgi ng spoil)
27 July - 2 August 81,810
246,410
OOTES
l'A33 Dredging in Swing Basin, Harbour & seaward along Pla1;ypus
Channel l1\:1inly to l3eacons 11-12.
1984 Dredging in Swing Basin, Harbour & seaward along Pla1;ypus
Channel 11I:1inly to Beacons 13-14.
1~5 Dredging in Platypus Channel, Harbour entrance to 11 and 12
1'klG Oredging in Harbour & seaward along Plawpus Channel l1\:1inly to
l3eacons 11-12, with a little to 7-8.
1~7 Dredging in Swing Basin & seaward along Plawpus Channel l1\:1inly
to l3eacons 11-12.
1988 Dredging in Swing Basin, I3erths & Channel (locations not specified
in earlier period, but seaward to Beacons 7 &8 in later period);
511\:111 arount of dredging in sea Channel (dog-leg to l1\:1in Plawpus
Channel seaward of 7 & 8) in earl ier period.
1983-88 Dredge spoil deposited in deep draft dlJl1J site (Figure 1).
102
TABLE 5
Air Photographs used in this Report
Date Area Covered Type SCale AeriaI Surveyor Source
1941 E of Ross Rnnuth - Crocodi1e Ck B &W 1:36,945 IWlF D. Hopley,
JaJ1l:!s Cook Universi1(y
cl942 S Ro.ves Ba.Y - E of Ross Rnnuth B&W enlarge- IWlF Townsville Ci1(y Council
Ireflts
1-7.6.59 Magnetic Is,Shelly Beach-Alligator Ck B &W 1:11,520 Adastra Townsville Ci1(y Council
11-18.6.61 Magnetic Is, Shelly Beach-Cocoa Ck B &W 1:~,502 CAB Geograpy Deparbrent
James Cook University
18.6.61 Magnetic Is, Shelly Beach - Gape B &W 1:86,502 CAB AIMS
Cleveland
11.8.61 Magnetic Is, Shelly Beach, T'ville
Harbour - E Cleveland Ba.Y B &W 1:24,049 Adastra Geograptjy Deparbrent
James Cook University
788.71 Ma9netic Is, Shelly Beach -
E Cleveland Ba.Y B&W 1:31,680 MaJIDlkers Townsville City Council
5-11.10.73 Magnetic Is, Cape Pallarenda-Gape
Cleveland B &W 1:12,<:66 f1/lM Townsville Port Authority
30.5.74 & Magnetic Is, Cape Pallarenda-Gape Beach
14.6.74 Cleveland Colour 1: 12,lXXJ Protection Geo9rapt(y Department
Authori1(y James Cook University
28.11. 78 Magnetic Is, Cape Pallarenda-Gape
Cleveland Colour 1: 12,lXXJ IFA Surmap
14-15.7.81 Magnetic Is, Cape Pallarenda-Cape
Cleveland Colour 1: 12,lXXJ IFA Surmap
15&24.6.85 Magnetic Is, Cape Pallarenda-Cape
28.6.85 & Cleveland Colour 1: 12,lXXJ IFA Surmap
15.7.85
11.7.85 Magnetic Is - Cleveland Ba.Y area Colour 1:50,lXXJ IFA Surmap
28.5.88 S Magnetic Is, Cape Pallarenda-
Sandfly Ck (nnsaic) Colour l:lO,lXXJ f1/lM Townsville Ci1(y Council
30.6.88 Magnetic Is, Pallarenda-
E Cleveland Ba.Y Colour 1: 28,575 DHopley Sir GFisher Centre
James Cook University
103
TABLE 6
Beach Protecti on Authori 1;y Cross Profil es - Summy of Changes
T(/(//1sville Harbour to Wof Shelly Beach
Profile No No of Dates
TMl Surveys
19 1 Feb 1~
20 1 "
20.4 1 Jan 1983
20.5 1 "
20.6 1 "
20.7 1 "
20.8 1 "
20.9 1 "
21 2 2/1~ &1/1983
22 2 " "
23 2 " "
24 2 " "
25 2 " "
26 2 " "
27 2 2/1982 &2/1983
28 2 " "
29 2 " "
30 2 " "
31 2 " "
" "
32 2 " "
33 2 " "
34 2 " "
25 2 " "
36 2 " "
37 2 " "
38 2 " "
places !J50-1600.
39 2 "
40 2 "
41 2 "
42 2 "
43 2 "
44 2 "
46 2 "
48 2 " "
50 2 " "
Cross Profile Changes (distances in mfrom lan<i-lard end)
Small change to upper beach swash bars - almost no change to
2,000 seaward of coast.
Swash bar on upper beach slightly seaward in 1983. Slight erosion
to 2,000.
51 ight change throughout 2,000.
Small accretion throughout most of 2,000.
Slight accretion to c 270, slight erosion in places to 1650.
Small accretion at top of upper beach, small accretion at
intervals to 1950.
Small accretion at top of upper beach. Sl ight accretion & erosion
to large sand bars 200-750. Slight accretion seaward of 1300.
Small accretion throughout, sand bars more developed especially
1andward of 1000.
Slight accretion throughout most of profile, sand bars more
developed 1an<loiard of 750.
Slight accretion 1an<i-lard of 750. Very slight erosion at
interva1s between 750 & 2000.
Sl ight accreti on & erosion 1an<i-lard of 500 as bars became more
pronounced. Slight overall accretion 500 to 2000.
Bars well developed 1an<i-lard of 750.
Small scale erosion &accretion as small bars moved slightly
1an<i-lard of 1250. Slight erosion seaward to 2000.
Slight erosion & accretion as bars moved slightly along l'.I101e
profil e 0-2000.
Sl ight erosion & accretion throughout with bar moverent.
Sli9ht erosion & accretion throughout with subdued bar moverent.
Sl ight accretion along a111'OSt l'.I101e profile.
Slight accretion &erosion along profile including Virago shoal.
Erosion of seaward dune slope.
Slight erosion with bar deve10prent 0-350. Slight accretion in
Slight accretion throughout, with little erosion in places.
Slight accretion 0-250, slight erosion 250-2000.
Slight erosion throughout, erosion of dll1e face.
Sl ight erosion throughout, except small accretion on upper beach.
Slight accretion throughout to 2250.
Sl ight accreti on throughout to 2000.
Slight erosion in places, especially 100-500, slight accretion
1an<i-lard of 100.
Very slight erosion &accretion at intervals.
Very slight erosion at intervals.
104
Very slight erosion & accretion in places 0-1950.
Very slight erosion &accretion in places 0-1950.
Very slight erosion &accretion in places 0-1950.
Slight erosion OOninant 0-1950, IllJst marked 25-600.
Slight accretion cbninant 0-1000, v slight erosion 1000-1950.
2 3/1~ & 1/1933
2 " "
2 3/1~ & 1/1933
1 3/1~
2 " "
2 " "
2 2/1982 & 1/1983
2 " "
1 3/1982
2 2/1~2 & 1/1933
2 " "
2 " "
1 3/1982
1 "
2 2/1~ & 2/1933
1 3/1982
1 "
1 "
2 3/1~2 & 1/1933
2 " "
2 " "
2 " "
1 3/1982
Localities of profiles SOONn in Figure 14
The small scale vertical erosional and accretional changes described in this Table are of the
order of O.lm to 0.2m.
Cross Profile Changes (distances in mfran 1anGiard end)
Very slight erosion & accretion with sand bar develojlrel1t.
Very sl ight erosion & accretion with lanGiard sand bar rrovement
seaward of 500.
Very sl ight erosion & accretion with sand bar develojlTent.
Magnetic Island fran Picnic Ba,y to Horseshoe Bqy
Slight erosion & accretion throughout. Accretion of sand
bars 450-750.
Slight erosion in places OOninant.
Slight erosion &accretion in places.
Very slight erosion &accretion in places.
Erosion & accretion related to sand bar develojlTent 0-600. Sl ight
accreti on cbninant 600-2000.
Slight erosion &accretion alternating along 0-2000 profile.
Erosion 0-400, v slight altemating accretion & erosion 400-1900.
Alternating accretion & erosion 0-500, slight accretion
OOninant 500-1950.
Slight accretion & erosion in places 0-1500.
Slight erosion 0-350, accretion 350-600, & v slight accretion
in places 600-1950.
TABLE 6 continued
Profile No No of Dates
Ta.vn Surv~s
52 2 " "
55 2 " "
57 2 " "
102
103
104
105
106
100
109
110
III
112
113
114
115
116
117
130
132
134
135
137
139
141
143
Notes: 1
2
105
TABlE 7
TOMlsville Port Authorit;y Cross Profiles - SLJnnary of ChangeS
TOMlsville Harbour to Cape Pa11arenda
26.1. 78-3.11. 78
3.11.78-11.6.79
11. 6. 79-27.3.00
27.3.80-9.3. !Q
9.3.!Q-28.3.83
Run 1
Run 2
Run 3
Run 4
Run 5
Run 1
Run 2
Run 3
Run 4
Run 5
Run 1
Run 2
Run 3
Run 4
Run 5
Run 1
Run 2
Run 3
Run 4
Run 5
Run 1
Run 2
Run 3
Cross Profile Changes (distances in mfrom 1ancWard end)
Little change
Li ttle change
Li ttl e change
Slight variations (= erosion & accretion) in sand bars & troughs G-WJ
Sl ight variations in upper part of profi1e 0-200
Little change
Slight upper beach erosion, no change otherwise
Little change
Sl ight vari ations in sand bars & troughs 0-850
Slight variations in upper beach & low sand ridges to 1000
Li ttl e change
Slight upper beach accretion, slight accretion in places seaward
Sl ight upper beach variations, sl ight accretion in places seaward
Slight variation (mainly erosion) in sand ridges to c.85O
Slight variation in upper beach, mainly to 200
(LancWard part of profiles not surveyed, 047 to 0-87 on different runs,
on 9.3.!Q)
Slight erosion to 850, almost no change seaward
Slight erosion in places
Slight erosion &accretion places
Sl ight variations in sand bars & troughs 47-850
Slight variations in low sand ridges throughout profile
(LancWard part of profiles 0-87 not surv~ed on 28.3.83)
Little change
Little change, slight accretion 87-450
Li ttl e change
Notes: 1 Local it;y of profiles shOMl in Figure 15
2 The small scale vertical erosional and accretiona1 changes described in this Table are of the
order of O.lm to 0.2m.
106
TABLE B
Townsville Rainfall Records (mm)
Bureau of MeteoroloGV data for Townsville Pilot Station 1871-1940 and
Townsville Airport 1941 -
•
presented· in hydrological years beginning 1 October.
YEAR OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP TOTAL
1871/72 82 12 122 565 214 69 28 21 11 4 1 1 1130
1872/73 24 170 368 309 309 183 55 9 171 0 12 0 1610
1873/74 6 33 271 479 376 192 111 45 55 99 2 0 1669
1874/75 54 0 275 236 600 31 467 123 11 0 0 0 1797
1875/76 0 25 38 86 216 162 17 206 48 0 0 0 798
1876/77 0 15 96 341 871 313 103 4 18 21 0 34 1816
1877/78 7 6 69 77 200 347 3 51 51 14 35 6 866
1878/79 96 41 57 138 164 483 309 46 28 9 83 2 1456
1879/80 76 15 0 318 364 34 83 0 0 11 7 0 908
1880/81 37 34 153 33 426 422 214 22 11 0 0 45 1397
1881/82 1 52 36 38 493 492 104 6 55 12 0 3 1292
1882/83 136 29 52 41 673 8 46 72 0 0 0 0 11357
1883/84 0 125 49 15 516 371 5 29 12 28 0 31 1181
1884/8:> 0 21 215 375 36 99 50 1 22 0 10 0 829
1885/86 0 3 311 70 225 122 261 23 110 80 15 8 12?8
1886/87 48 34 191 300 16~ 601 142 12 18 2 11 12 1533
1887/88 5 28 153 53 437 35 9 1 0 4 1 16 742
1888/89 13 8 51 57 115 82 196 25 69 39 6 94 742
1889/90 20 174 333 608 574 571 18 123 7 54 1 178 2661
1890/91 11 6 11 420 626 328 2~4 64 181 1 11 6 1889
1891/92 45 20 6 831 14 98 4 172 13 3 3 18 1227
1892/93 141 10 31 :) 1 219 287 8 2 11 2 113 0 875
1893/94 613 89 ~'/ 718 474 191 592 16 160 3 2 24 2361.) ~
1894/95 39 1713 95 215 821 7 119 8 14 7 11 22 1528
1895/96 16 3 193 751 561 279 36 3 8 12 7 1 18713
1896/97 , 28 113 5~1 9 190 154 4 23 26 5 5 5 1010,
1897/98 7J 44 188 357 515 55 "" 0 19 6 4 39 1322LL
1898/99 5 1 52 259 272 278 96 15 13 2121 23 0 1021
1899/013 9 4 14 536 " 43 27 59 10 15 3 6 728L
19013/01 23 19 379 329 118 75 25 9 6 41 5 10313
1901/02 0" 0 20 39 75 51 10 2 3 121 1 0 236
.' L .'
1902/133 7 1 157 99 1:30 587 52 39 27 1 4 11 117 :1
19133/134 ~" 1 E,2 483 139 ' ~" 102 26 6 1 0 0 1 1104OL .l- .Je.
19134/05 93 30 l4 ~l 348 50 51 163 13 9 17 " 97 11318<-
1905/06 14 1 0 13 :::55 3fl7 109 10 46 0 121 12 83 912_u C'
19136/07 .37 187 .J:,u 317 197 187 26 79 61 0 2 4 1463
1907/08 1 72 616 313 .l9R 229 10 57 121 43 7 ., 1551,
1908/09 40 c ~. 176 43 178 33 27 38 21 15 3 :-,84v L
1909/10 :,3 00 282 587 276 440 "0 7 28 9 0 Sf) 1,S68,_'v ,-'U
1910/11 3 64 ,~n 648 486 121 83 2 3 121 0 0 1582.l- / Go
1911/12 113 8 c: 'J, 41 192 178 11 :1 16 114 17 4 ,) 779
1912/13 16 68 37 287 ':l ...... '7 19S 187 57 14 121 0 13 1 (") .... 1,_'.J I _':"':'..1.
1913/1·1 0 0 171 379 1:1 364 124 16 116 2 1 0 1302U
1914/15 10 3 108 230 ~d 1 19 9 1 4 14 " 452~
1915/16 '1 0 -32 251 192 1°",) 1 15 7 86 16 1 845U UL
1916/17 (;5 8 ~I 157 5.3 .3 5113 243 83 61 2
""
53 6 2108
1917/18 9 3 3~) 280 705 181 65 67 121 1 0 32 5 1680
1918/19 0 63 20 168 212 ~,0 71 ., 9 1 1 3 605,
1919/20 " 4 17 298 102 47 469 136 26 7 41 48 119 ~>'-'
1920/21 ~ 1 19 31 146 35 75 9 52 15 88 4 45 550.J ..L
1921/22 147 13 141 133 339 34 ., 6 5 38 13 6 856,
1922/23 48 :, 173 29 7 17 30 18 62 2 43 1 435
1923/24 0 9 52 39 242 324 133 4 23 0 68 31 925
1924/25 79 148 212 278 3134 187 1 121 44 3 50 34 134121
1925/26 " 21 128 95 353 45 1 0 27 5 1 117 795L
1926/27 " 15 189 473 511 77 11 1 106 137 121 27 1549L
107
TABLE 8 continued
YEAR OCT NOV DEC ,JAN FEB MAR APR NAY ,H.lN ,JUL AUG SEP TOTAL
1927/28 11 2 216 201 245 132 4 0 12 1 0 0 874
18;::8/29 16 91 96 405 133 25~ 64 0 52 ,., 0 4 111 [I~
1929/30 3 9 56 447 195 26 0 114 3fl P- I 0 894
1930/31 274 ,., 23 36 89 117 76 12 3 " 3 8 61J6v ~
1931/32 94 139 211 225 56 179 32 57 4 e: 0 0 997
1932/33 3 50 219 152 255 0 143 12 99 32 47 23 1043u
1933/34 31 149 290 352 360 22 43 6 61 21 7 5 1347
1834/35 10 78 20 70 15 71 12 60 10 15 (7, 1 362
1935/36 5 9 13 195 728 240 fl5 14 125 7 0 5 13G7
1936/37 0 63 179 140 119 247 4 3 19 16 0 0 7913
1937/38 2 49 2 386 390 42 2 10 24 94 0 0 1001
1938/39 19 68 4 79 244 176 41 11 55 ,., 14 0 713~
1939/40 r. 20 17 209 538 159 62 3 10 0 59 2 1084v
19110/41 3 17 6 1015 150 402 174 61 4 2 1 1 1838
1941/42
'"
101 53 86 299 11 58 18 76 86 5 29 O?"',v __
1942/43 26 <I 419 135 595 22 23 1 25 0 3 45 12G8
1943/44 2 42 19 93 454 382 38 9 12 32 1 :> 1 1099
1944/45 12 6 74 77 307 430 15 41 75 11 0 ,., 1050~
1945/46 22 24 26 398 47 426 1 5 0 0 0 0 949
1946/47 " 4 31 9 735 29 0 27 4 0 83 67 991~
1947/48 3 150 34 222 104 118 5 36 3 27 1 ,., 705'-
1948/49 " 25 88 3013 296 560 62 8 0 1 0 5 1347'-
1949/50 50 11 18 417 304 612 181 4? 37 1?: ,., 6 1853~
1950/51 39 280 103 849 34 81 6 25 10 2 7 1 1437
1951/52 19 6 4 465 91 64 131 11 36 ,., 2 6 838v
1952/53 26 27 62 1142 497 37 4 0 0 1 36 0 1840v
1953/54 18 11 47 131 674 159 285 2 15 29 8 4 1383
1954/55 93 18 85 79 688 426 90 150 20 10 0 1 16613
1955/56 29 10 59 339 422 379 122 134 81 45 39 20 1679
1956/57 13 117 318 237 90 251 8 13 10 17 " 0 1076'-
1957/58 49 46 15 131 431 326 307 5 98 0 2 6 1416
1958/59 3 25 89 377 70 155 115 57 5 2 0 0 898
1959/60 0 52 408 138 560 366 9 45 7 1 1 4 1591
1960/61 11 135 90 34 221 118 9 8 0 3 9 0 638
1961/62 4 130 61 198 399 91 32 4 16 14 7 11 967
1962/63 1 27 79 411 144 361 61 5 3 0 32 0 1124
1963/64 2 12 39 172 514 138 38 38 54 26 3 0 1036
1964/65 51 48 177 276 36 306 97 25 8 1 1 0 1026
1965/66 8 5 270 240 100 31 22 31 10 2 16 0 735
1966/67 10 52 18 108 186 189 3 6 107 1 7 0 687
1967/68 18 10 132 349 904 46 32 72 0 12 0 6 1581
1968/69 14 4 44 174 63 52 1 9 37 0 0 0 398
1969/70 27 38 63 44 91 275 20 0 4 0 53 3 618
1970/71 5 76 149 103 195 253 36 29 42 10 43 0 941
1971/72 20 27 347 600 171 210 1 23 11 1 0 6 1417
1972/73 0 31 37 219 465 199 30 10 5 2 0 55 1053
1973/74 58 116 351 878 442 143 43 48 3 0 54 5 2141
1974/75 4 37 52 239 67 270 17 2 4 3 36 81 812
1975/76 253 19 458 283 495 222 15 2 1 3 1 3 1755
1976/77 23 71 318 98 478 272 85 181 0 0 22 21 1569
1977/78 2 33 128 437 210 76 115 37 3 22 29 18 1110
1978/79 13 49 61 184 217 310 53 5 34 9 0 11 946
1979/80 16 0 185 257 95 154 21 82 4 10 2 0 826
1980/81 18 2 76 745 321 18 97 118 18 16 28 1 1458
1981/82 5 333 61 164 182 113 109 26 9 2 5 27 1036
1982/83 0 7 46 147 4 178 152 152 71 0 5 2 764
108
TABLE 8 continued
YEAR OCT NOV DEC JAN FEB !1A Ii: APR MAY JON JUL AUG SEP TOTAL
1983/84 16 44 12 344 299 98 26
""
.-, 59 6 2i 927
1984/8~1 20 39 48 .-,~ ~~8 0'-' 26 28 ,~ .,,> 28 4 1 4~3.J .•: vb <. ,-
1985/86 100 158 47 255 114 3(1 2R 52 1 " 26 38 8:,i.<.
1986/87 26 26 2" 216 36 47 7 15 13 10 7 r. 480J ..
1987/88 19 57 2910 15 208 10 66 13
MEAN .. 29 50 126 284 289 188 74 34 20 16 13 1 ~, 1147
109
TAaE 9a
ROSS RIVER AT ROSS RIVER OI\M HEAO#.TER (catchirent area 75U<nl)
1'mTHLY PID PNNl.I\L VOLlM:S IN t>[G\LITRES AND IWNLll\L RUNcrF IN MILLIMETRES
Clim- OCt Nov Dec Jan Feb Mar Apr Ma,y June July Aug Sept Clinatic Runoff
atic Year Total
Year
1974-75 U 0 0 2 I 9,007 13,715 2 0 0 0 0 22,727 30
1975-76 U U 2,995 12,682 191,009 48,184 1,470 0 0 0 0 0 256,420 342
1976-77 0 0 39,990 3,605 104,412 90,866 466 43,730 909 0 0 0 283,978 379
1977-78 0 0 0 19,438 109,544 0 0 0 0 0 0 0 128,%2 172
1978-79 0 0 0 0 31,588 12,249 25 2 0 0 0 0 43,864 58
1979-80 0 0 o 52,784 5,225 0 0 0 0 0 0 0 58,0J9 77
1980-81 0 0 o 138,660 164,012 0 0 0 1 0 0 0 302,672 404
1%1-87 No flOi/ over spillwqy
13yrM:ANS 0 U 3,307 17,475 46,605 12,331 1,206 3,364 70 0 0 0 84,358 209*
* 7 yr M:JW
110
TABLE 9b
ALLIGATOR CREEK AT ALLENDALE (catchment area 69km2)
MONTHLY AND ANNUAL VOLUMES IN MEGALITRES AND ANNUAL RUNOFF IN MILLIMETRES
Climatic October November December January February March April May June July August September Climatic Runoff
Year Year Milli-
Total metres
1973-74
1974-75 29 0 0 4.697 3.288 8.440 5.265 1.365 555 152 402 702 24.896 361
1975-76 1, 582 39 9.875 6.098 33.226 10.247 2.580 1.125 598 735 368 130 66.601 965
1976-77 29 25 9.656 1.911 19.777 20.999 2.2"5 10.115 1.153 743 185 96 66.932 970
~ 1977-78 97 26 373 21.522 5.526 2.777 2.208 1•131 741 444 130 147 35.121 509
~ 1978-79 8 38 252 3.879 12.253 26.307 2.062 1.010 521 165 57 0 46.550 675
1979-80 0 0 160 8.398 3.540 6.649 1.358 1.299 819 483 126 18 22.849 331
1980-81 0 0 0 32.446 21.134 2.129 1.836 2.029 1.179 1.075 654 121 62.602 907
1981-82 0 556 611 168 443 1.617 2.023 722 183 5 0 0 6.327 92
1982-83 0 0 0 423 88 841 1.956 4.429 1.431 571 57 0 9.797 142
1983-84 0 0 0 2.831 7.367 2.251 1.286 771 593 544 570 18 16.230 235
1984-85 0 0 0 0 2.026 4.942 1.651 1.000 985 468 21 0 11.093 161
1985-86 1.420 1.165 634 5.241 10.911 1.761 1.444 2.783 1.214 849 763 690 28.875 418
1986-87 2.112 366 567 1.001 3.857 1.238 1.003 1.9051.142 843 914
MEANS 406 170 1.702 6.816 9.495 6.938 2.071 2.283 855 544 327 160 33.156 481
NOTE: "-" INDICATES INCOMPLETE RECORD
TABLE 9c
BLACK RIVER AT BRUCE HIGHWAY (Catchment area 260km2)
MONTHLY AND ANNUAL VOLUMES IN MEGALITRES AND ANNUAL RUNOFF IN MILLIMETRES
Climatic October November December January February March April May June July August September Climatic Runnoff
Year Year Mill i-
Total metres
1972-73
-
- - - - - 7.717 3.966 733 366 494 253
1973-74 200 233 15.540 186.358 136.137 51.095 4.953 2.150 1.211 561 401 213 399.051 1 .535
1974-75 24 2 D 7.506 1.116 28.179 6.860 1.174 238 104 35 17 45.254 174
1975-76 1.465 420 40.685 6.387 38.756 - - - 107 147 17 0
1976-77 0 199 24.363 566 36.393 35.526 8.958 - - - - 41
1977-78 7 0 1.587 23,913 6.922 5.414 7.286 1.858 499 15 1 0 47.501 183
~ 1978-79 0 0 163 6.327 22.527 41 •168 1.501 444 155 40 12 3 72.341 278~
N 1979-80 0 0 269 31.514 8.278 8.373 1.015 1.363 1.043 155 7 0 52.015 200
1980-81 0 0 0 88.861 72.923 14.497 3.614 8.437 1.622 1.011 467 58 191.491 737
1981-82 13 1.377 163 94 1.886 1.855 620 55 0 0 0 0 6.061 23
1982-83 0 0 0 518 0 1.766 4.376 19.632 1.175 175 5 0 27.648 106
1983-84 0 0 0 7,612 29.292 6.510 718 26 0 23 0 0 44.181 170
1984-85 0 0 0 0 7 42 3 3 1 0 0 0 55 0
1985-86 0 86 1 1,806 18.992 8 0 175 0 0 0 0 21.069 81
1986-87 308 1 0 1 39 0 0 0 0 0 0
MEANS 144 165 5.912 25,819 26.662 14.956 3.401 3.022 485 185 103 56 82.424 317
NOTE: II II INDICATES IMCOMPLETE RECORD
TABLE 10
Tropical Cyclones affecting
Major Burdekin River Floods
the Burdekin Delta Area and
1940-1980
Tropical Cyclone
Date Pressure
(mb)
07.04.40
28.03.44
Date
20.02.40
09.04.40
05.03.46
Major Flood
Instant-
aneous
max(cumecs)
24,989
38,290
40.392
Da i 1Y
Volume
( M1 )
1.987,633
2,756,685
3.040,461
06.03.56 961
20.02.58
05.02.47
08.03.50
07.02.54
01.04.58
16.02.59
990
968
948
09.03.50
08.02.54
24.02.58
03.04.58
17.02.59
17.02.68
30,398
20.305
26,240
36,000
19,120
25,964
2.272.238
1.528.884
2.171,783
2.456,134
1,304,553
2.068.939
24.12.71952
19.12.73 988
11.01.72
25.01.74
26.140
26,618
1.956,386
2.202.180
Flood data after Queensland Water Resources Commission
Cyclone data after R.S. Lourensz. 1977, with additional
information from P.M. Fleming.
Notes
Major floods defined as over 19,000 cumecs instantaneous
flow.
1940-50 flood data from Home Hill gauging station.
1951-80 flood data from Clare gauging station.
113
TABLE 11
Cape Cleveland Percentaqe Occurrence ~f Wind Speed Versus Direction.
Based on 30 years of Bureau of Meteorology records.
:URtA~ 0f ~ETE0~0L0Gl - SU~fACE ~I~O A~ALTSI5
DfllUNuq OCCllFREe" f ,), ,DnD y'O'Il:; ,)rHCTT,'., ':A::'O~. \,) 'fA'-, ,',; ",,',H'O:: •. --- I
FIRS' 'EAR lQ~7 LAST YEAR lQ~6 "lI~iH~ ')f ~15SI~G (\ESERVATIO.llS (AS P€RCEHTAl;E 'H ,lo';AX:"U~ ':>')55::-.E: 1.11 'J
~
~
..,.
STATI('N :,~2')~S--CiPf--(lE'JELAN['l UGIjT'-':'LIH - q 11 5. 1L7 ')' E ~~.,) ;.., €LEv I
I .- - I
''R¥ ,'9M'...H"IIRS ,::r EFo:.pIIU" 1')9')0 'lOIlRS !" llucH 191:] HeHIR; I n APR!! Q9:B......!:t ..,t!P:: ! q
1 SPEEiI ("'I'lRl I SPEH ((/'II/HRl r SPEEO (K)C/HR) I SPEEO (JIII/HI\)
,,,., c"P" (IPI! COre'
41' 6112'314151'" 51' 61'21311,151 A 41 ~ 61'21~1/'lS1 A 31' 611213141S1;'
I TO T0 TO TO TO Tv & l I TO TO TO T0 TO T0 t l I TO TO TO TO TO TO & l TO TO TO TO TO TO & l
OliN' c; 1Q 20 3') La 1;0!lp! DIRN! c; 1Q '0 30 40 "0 IlP---l.- DIh! Ii 1? ?? 31 41 Sf)!lP! oreN 5'0 2C '0 Lj' 'O!lP !
1 1 1
HI'3(,2' q NI"" (, 1111'" .(. /II .1' ,
ICE' ) , 6 , 1 ~ .; 3 ICE'!"'" 8 HE 1 • , , 1. 6 ME ." ~ ~ ;
E I 1 3 5 ~ 2 1 • 16 E t , 4 I. 2 1 , • 1~ F t 1 2 3 2 , ., • 8 E' 2 2 1 ••• 5
SE 1 1 I. 11. 15 6 2 ·41 SF I 1 6 H 1~ 1 l 5) SE I 2 61626'0 2 ·6} SE 2 S 17 20t 17 5 • 71.
S' 1 1 , '.1-' L (! r , 1 ? J. , S I ' , ? l. 1 t 1 S 1 1 , 3' 9
SW I , 2 , ,. 6 sw I 1 2 , ,. • 5 SW I 2 2 2 1 5 SI/ , 2 ~ ~ • I.
Wi"" 2 wI····· 1 i···· t 1 W. II
U , ,1. 1:. 6 NU 1 1 , , ,., , 6 MH I t 1 , • ? ICH • t ._-,---
1 1 ,
AL:' I 6 ~~ }1.?5 q I. • ALL' 5,q}1 26 q } , ALL I 6 15 26 B 12 3 ~ ALL' 12 n }Z Zt) 5 •
JANUARY
Ill'). ,)~ I)es. Q25
1S00 HOURS lST FEERUART
NO. OF OSS. 81.7
'500 HOURS LST IIIARCH
NO. OF 08S. 921
1111 'OuRS LST APRIL
H'). (,~ ')8S. ~Q9
'500 M')URS UT
, l' " "" , ,
I ' SPEED ',,'H8' ---l.- SPUD (('fWe) 'SpeED 'O/He' '(peED rY·'Hil
CALIIII CAL"' CAL"I (ALIIII
, I 1 6 11 21 31 '1 51 A 1 I 1 6 11 21 3' I., 51 A ., 1 6" 21 3' 41 S1 A 1 I 1 6" 2' 51 I., 51 .,
.,-:-,-1-1-'T~O TO TO TO TO~ I ' TO TO TO TO TO .I.O. I' I TO TO Ttl TO TO TO t t ! TO TO TQ TO TO TO t '
DIR., I 10 20 lO 40 10 U' L DI'" I 10 20 30 40 10 U' l Dl''', I 1~ 20 30 40 10 U' L 01'" I 10 20 l') 4') \0 l" L
I 1 1
, , 3 9 L •• 18 • I , 3 6---L_" ..1.l.-__ .! 1 , , ,. 9 N'" -L. <.- 5 I
HE I 1 5'6 8 •• 32 HE I 1 4 13 4 •• 22 HE I 1 6 Q I.. 2~ HE 1 1 6 6 2 ~ t 15
E I • 2 ~ 14 ~ 2 , 35 F I 1 212'6 7 4 • 42 F I 1 } 11 17 9 4 • 45 E I .. 4 "'9'2 (, • 50
Sf ! '" 1. '.'" SF'" ..4..-...0....----",-' • 17 SF'. 1 , 9 6 ? • U Sf I 1 3.....10 10 , • 2? I
SI ttl • t 51 •• ••• , 51 'W" , SI •• ~. ,
SW I , SW 1 • • .. •• ., Sw I • t t • 1 SIo: I •• ~ II 1
W' • \I' •• H" • W!.,. ,. I
HW , • 1 1 •• 2 Hili I • • , 1 , 5 NW I • t 1 .,. 2 HW" 1 , 1
I I I I
? ,? 1.( " " " at; I '" '''' 'Q " '" , i'l I "1. " " 1;.. ~ 1 i' ,
Ht). ,)F ')E5. 93(1 HO: OF ,)eS. 81.6 NO. OF 08S. 92~ Nc). ')F I)SS. ~97
I ., OCCURRED EUI ! FSS THU a c;, wFRr'NT __h__ Pp.-,DIlCfO 61' .. ! ~ 5 29, 7186
"r
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to , .......... ' I"V
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115
TABLE " continued
eU~E.u o~ ~£TEOROLOGT • SURFACE WIND A~AlTS!~
PFRrFNTAr.r nrruRRFHCF ~f SPEED ~f~~u~ nu~fr:10~ C!~fO ~~ ~n "fiRe: ~f Rfr~RO(
FIRST YEAR lQ57 LAST HAIl '986 "'L',IIlEE,Q ,); IltS:;!HG ')BSERVATIQHS (AS PERCENTAGE Of "., ... X1"'u'" p'JSSIeLEJ 2.21 1
I STATIOH ')32005 CAPE CLEVELAND LlGHftl')USE lQ " S, 14701 E 58.) " ELEv I
tCl>" .. I:lCD I"l~')(' ... ,"lIrDC: • <:T t'lrT"l:HD nQnn H!'!ull" I <: T ... nVF~"'1 ,p "loon W(\IIlH I <: T n~n""cF~ I'1Qr1n ~1111R <: J '- T
SPEED (K/'(/HliI:l\ SPEED (K"'HR) 1 SPEED ((~/HR) I SPEEO (~""HR) I
I CAS·: 1 6" 21 31 " 51... °3":, 6 11 21 31 " 51 A C4 3!!\ 1 6" 21 31 4' 51 A rA 3M: 1 6,,?1 31 ~1 51 A
I 10 TO TO TO TO TO 1 LITO TO TO TO TO TO' LITO TO TO TO TO TO & L I TO TO T'J TO TO TI) & l
... " .." C"., "'I 'V'I Ll''1 "n III) !'I 1 11111 1 "11'\'0 \0 L.1"l <f'I Ill> I /'ITDII/! c:,n >n \n L(\ c:n III) "Tihl! c: 1(\ ,n t.n Ln (') liP
. 18
n I J ., 11 , . . }J ME 1 J 6
"
l , , 18
. . , . , J .. J r I , • '9l 1 • 2@
?
. l
I
,
_..9..-
6 I •
I ·1 I I
H1123' 6 H11453· 1} H114104. 19 HI"SS
ME I ' 3 5 ,. " ME 1 , 5 "7 L' 18 -
E I , 4 S 2 , • ., 3 E I , 4 6 6 3 1 • 20 ~ .) g ~ ( ,~ t'.. .
SE I , 5"'6" l • 53 SE I • ,,, " S, l5 SE I • I I 10 " n SE I • , ~ H)
"". , ~! •• 1t. , "------L:t..1 1 ~! .. , .. ,
~
~
,en
00, Of OBS. 867 00. Of OBS. 1~9 00. Of OSS. "I 00. 0' OSS.~
SEPTE"SE' 1\00 'OU'S LST OCT08EI 1530 HOuRS LST _OVE~eER 'SOO "OURS l5T DECE"SER 1500 HOUR5 L5T
I r SPEED '(M'He' '~PEFD (UIHP' I SPEED (u/Hi' ! SPEED 'Y"HpJ
CAl"'l CAl"'1 CAL"l CAl"1
1 I 1 611 21 31 41 51. ., I 1 6" 2' 3' 4' 51 A • I 1 6 11 21 31 41 51 A to I 1 6 i1 21 31 41 51 "
DIANt4 ~~ ~~ ;0 ~O ;0 ~p l DUN: T~ t~ is 38 18 ;~ ~p L DIU: r~ 18 ;0 ;~ 48 ;0 ~p ~ DIRN: T~ 18 ;~ 3~ r~ 5~ ~p l I
I I I
'; ! "0' 17 MI., "-.-1..-. • 72 .IL..1.. • L'5 9 ,. 29 "., "'0' 27
.E I , 6 17 6 •• II oE I 1 5 16 9 I' II oE I • \ 19 II I' II oE 1 \ 18 11 1. l6
Ell 9 1\ 9 \ 1 19 E I • 1 8 17 8 l 1 H Ell 7 10 6 l , II E" 8" \ l • 17
Sf It' , 3 , "0 ~::! t t .. 2 2 t -L.-S.F Itt , 1 1 • SF to' 2 , , • 6 I
51 to to to 51 • ., t 51 S .....
5w r •• • 5W 1 • to to • ~w I Sw ••• ,
HI·' • Wi WI t • W I
NW I 1 t • 1 _w r t 1 • 1 JilW I ... 1.. 1 N'II •• 1 ,
I I I
! , 13 ~9 '" " " , .lor I I 1 11'\ '\7 '\Ci t'\ L 1 "I I 1 1" ,? 32 1n L 1 ---.J..LL---.l.. 1. Q 1..2 ,\, 11"1
00. Of oes. 870 00; Of O'S. 197 00. 0' oes. 870 No). OF ')E5. ~~3
.. I'IffllPPFI\ RII' I FI::I:: hI'H (I c; P~H!="HT ~urFn RY ~ 1 ~" )0/ 7/R~
Monthly Wave Statistics for Wave Buoy near Cape Cleveland.
YEliri
75
"(fi,H,
11 Jlv
:v
"".,"Iii;
Il
J.Ol
D.6<l
6.49
7.09
Ie
2.21
0.J5
7.88
1.6<'1
I-;~MS hSIG h\t4A 1)
0.-17 0.66 l.JlJ 3.66
0.29 D.dj 0.&1 J.9/l
1.17 1.6~ 3.11. 5.67
0.16 G.'ll 0.35 7.42
IP
.1.6J
Ltij
7,fi2
7.15
77 J . ..,9
u.lJu
4.12
2.J8
2.47
0.2J
7.90
1.87
0.66
V.19
1.04
0.73
V.9J 1.62
0.27 0.48
1.44 2.72
0.J2 0.51
4.46
0.51
5.J1
2.84
5.15
0.87
8.11
J.02
75 1l
76
76 7
76 J
AV J.l. 2.J7 u.5'; O.7V l.ll J.99 4.5& 77 5
$ 0.54 O.Jl 0.7J O.JJ 0.58 0.13 1.09
MlX ~.64 J.J1 1.27 1.80 J.58 5.6u 7.40
Mlt''I 2.15 1.66 D.lJ U.18 O.JO 2.64 2.61
AV 7.87 7.0J O.J. 0.'8 0.86 J.85 '.95 71 6
9J 0.6J 0.27 0.17 0.75 0.'6 1.92 7.07
MIlX '.8J 7.75 0.86 l.ll 7.17 7.78 9.90
MI' 1.78 1.'8 0.08 0.11 0.19 7.15 1.J8
AV J.15 7.71 0 .•7 0.67 1.18 •. 18 4.99 71 7
!xl 0.51 O.JO o.n O.JJ 0.58 0.77 1.6<)
M4X '.J9 7.91 0.99 1.41 7.'7 6.07 9.16
I<1N 7.7J 1.58 O.lJ 0.18 0.J7 7.70 O.J'
Av 7.9J 7.09 0.J6 0.50 0.90 J.90 4.72 71 8
!I.J 0.48 0.76 0.18 0.75 0.4J 0.87 1.70
M<lX 4.05 7.89 0.85 1.71 7.08 6.Jl 9.59
MlfIt 2.09 1.6d 0.14 0.19 O.J" 2.47 1.19
AV J.07 2.2J 0.40 0.56 D.98 J.89 4.80
Y:J &.56 O.JJ 0.2,3 O.JJ 0.59· 0.8J 1.59
/o'I<X 4.26 2.99 1.10 1.55 J.OJ 5.68· 9.0J
"1~ 1.9J 1.57 0.09 0.17 0.25 2.14 1.4J
"V J.)l 7.JJ 0.'2 0.59 1.02 4.J1 5.0J
5IJ 0.47 0.25 0.17 0.74 D.42 0.75 1.27
"'AX •• 76 2.76 0.76 1.07 1.89 7.00 8.JJ
"1' 2.25 1.56 0.11·0.15 0.75 7.79 2.26
AV ).42 2.'5 0.55 0.77 1.J4 •. 41 5.06
9J 0.4.1 D.2J 0.19 0.27 0.46 0.6) 0.90
""X 4.41 2.87 0.95 1,)6 2.4J 6.04 6.67
"lh 2.J7 1.77 O.lJ 0.18 0.29 2.65 2.8'
AV ).54 2.51 0.5J 0.76 1.79 4.54 5.0'
Y) 0.47 0.24 0.20 0.28 0.50 0.55 0.84
/ofAX 5.18 J.1J 0.96 I.J5 2.4J 6.79 7.9J
Ml' 2.70 1.91 0.17 0.25 0.41 J.14 J.17
76 , "V J.49 7.45 0.67 0.88 1.57 4.5J 5 .•7 71 9
9J 0.47 0.78 o.n 0.J7 0.55 0.6. 1.00
M4~ ~.'5 J.01 1.7J 1.7' J.16 5.65 8.20
MIN 7.17 1.76 0.17 0.74 0.J6 7.7J 7.74
J.j\! J.26 2.U 0.4" 0.62 1.06 4.25 5.)2
Y.J D.5J 0.31 0.26 0.)7 D.6J 0.77 1.42
M4X 4.17 7.8) 1.0' 1.48 2.41 5.56 8.02
"1' 2.16 1,66 0.12 0.17 D.26 7.46 1.79
76 5 AV ).42 2.40 0.54 0.76 1.29 4.40 5.23 77 W
9J 0.41 0.76 0.19 0.27 0.50 0.5' 0.90
M4X ','07 7.78 0.97 l.J1 7.67 5.W 8.)1
"1' 7.76 1.58 0.11 0.15 0.75 7.74 7.71
IIV J.J6 2.37 0.5il 0.76 1.)11 d.)1J 5.l!
5IJ 0 .•1 0.26 0.22 D.J1 0.54 0.57 1.1)
MilA tl.29 2.8) 0.911.29 2.71J 5.46 7.65
Ni:~ 2.22 1.6tl 0.12 0.17 0.28 2.60 2.66
76 6 AV J.29 2.31 0.44 0.5J 1.09 !J.n 5.12 'Ii :t
9J 0.47 O.JO O.ll O.Jl 0.57 0.64 1.08
MIlX 4.J1 7.8' 1.06 1.48 7.81 5.47 8.4.
I"iIN 2.15 1.67 0.11 0.15 0.27 2.61 2.61
LlV J,22 2.31 u.45 0.6J 1.10 11.0 tl.87
9J 0.d6 (j.n 0.7) U.Jtl C..57 0.71 1.111
MAo 4.J2 2.98 1.1& 1.7J 2.83 6.40 8.1~
1~1,\ 2.11I; 1.85 0.18 0.25 G.d2 2.99 2.80
76 11 ,(IV 2.97 2.11 0.33 U.45 0.79 3.69 4.14 78 6
9J O.J. 0.22 D.U 0.19 0.J5 0.5J 1.79
MA); 3.80 2.70 0.8" 1.19 1.00 5.15 7.19
loll" 7.35 1.73 0.14 (j.20 D.J4 2.80 2.10
76 12 J.lV 2.96 7.16 0.J7 0.51 0.89 J.70 4.08 79 7
5U f).51 a.JJ o.n 0.31 0.550.71 1.24
MAX 4.";:lJ J.Y.i 1.27 1.71 J.Ol 5.l) 7.55
MI." 2.07 1.6J Ij.JJ u.Jl U.)2 2.48 2.00
71 4\! .1.71 2.)1 ~.1:l9 O.OS8 1.18 4.07 4.69 78 8
::v u.49 G.J2 Q.?5 I).J6 0.61 0.66 1.11
Nil;( 4.72 2.97 1.15 1.62 2.80 5.70 7.JII
Ml.\' 2.29 1.66 0.18 C.25 0.J9 2.84 2.18
~ .. J.?? 2.)5 0.52 n.n 1.27 •. 10 4.7J
5D 11.52 '1.27 0.26 a.37 0.64 0.81 1.3)
MAX 4.38 2.94 1.20 1.73 J.OJ 5.63 7.1J
MIN 2.Jl 1.";:, 0.18 0.25 0.65 2.65 2.45
~V JJJd 2.24 0.46 u.62 1.14 ).86 4.61
$ 0.75 0 ••6 V.J~ 0.51 J.91 1.08 1.98
MAX 4.01 2.89 0.97 l.Ju 2.49 5.03 6.76
Mlh 2.41 1,82 O.lJ 0.19 D.)2 2.8J 2.09
AV J.17 2.24 V.J7 u.57 0.91 J.98 4.57
SlJ 0.57 O.Jl V.lO 0.28 0.51 0.82 1.14
MAX 4.9J J.26 0.99 1.•7 2.69 6.0J 6.85
MIN 7.05 1.75 0.14 0.19 O.Jl 7.J1 2.47
AV J.67 2.56 0.68 0.96 1.66 '.66 5.74
9J 0.J2 0.17 0.18 0.25 0 ••5 0.51 0.77
!'AX 4.J4 J.02 1.11 1,59 2.70 5.66 6.55
/ofIN 2.92 2.16 O.JJ 0.46 0.81 J.J5 J.26
"V 2.9' 2.1J 0.28 0.J8 0.66 J.67 ~.06
5IJ 0.58 0.26 O.1J 0.18 O.JJ 0.88 1.47
/of4x 4.80 7.86 0.59 0.8' 1.54 5.99 7.40
Mlh 2.18 1.56 0.10 0.1. 0.2J 7.J8 1.95
AV J .•' 2.29 0.4J 0.61 1.0' 4.51 4.91
9J 0.59 0.2J 0.19 0.27 0.'8 1.10 1.25
/o'I<X 5.74 2.65 0.77 1.09 7.19 9.00 7.0J
M1' 7.47 1.54 0.10 0.15 0.77 2.8J 2.09
"V J.J) 7.J4 0.51 0.71 1,2' 4.29 4.8J
'" 0.J8 0.2J 0.22 O.Jl 0.52 0.54 1.07
M4< •• J7 7.9J 1.71 1.70 7.7D 5.78 7.J7
MJ,. 2.67 1.89 0.15 0.21 0.34 2.95 2.43
AV J.~5 2.J8 0.50 u.7l 1.24 4.5J 5.'J 17 12
50 0.J9 0.27 0.27 O.Jl 0.51 0.61 1.72
!'AX 4.4~ 2.87 0.92 l.JO 7.19 6.79 8.50
"W 7.50 1.74 0.15 0.22 0.'1 J.1O ).U
AV J.06 2.n 0.J8 0.5J 0.91 J.n '.58 78 2
9J 0.56 O.Jl D.lO 0.28 0.51 1.8J l.J9
"Ax J.96 7.90 0.89 1.77 2.27 5.5, 7.)J
"1' 2.07 1.66 0.11 u.16 V.25 7.71 7.07
76 7
76 8
76 9 AV ).03 2.19 0.35 D.li9 0.86 3.86 4.84 78 "
9J 0.51 D.Jl 0.22 O.Jl 0.55 0.68 1.65
MIl. 4.26 7.97 l.D5 1..8 2.88 5.78 d.29
"1' 2.02 1.59 D.l) 0.19 O.JJ 7.10 2.07
76 10 AV 7.87 2.16 V.J5 0.50 0.88 J.57 4.76 78 5
5lJ 0.44 D.n O.lb 0.20 0.37 0.68 1 .•111
M4X J.77 2.61 0.77 1.09 7.05 4.90 7.81
Ml,~ 1.85 1.6J 0.16 0.23 0.J9 1.91 1.85
77 ? I-lV ).27 2.J7 0.57 0.80 1.36 4.18 4.78 7& 9
Oil 0.71 0.'1 O.H U.48 0.&2 D.97 1.25
fo?l). "'.6t) J.09 1.)7 i.89 J.JO 6.15 7.06
Mi,\, 2.01 1.55 O.li 0.111 0.26 2.J5 1.85
uV J.21 2.2J 0.)6 0.51 0.91 •• JO 5.J6
'" 0.'9 0.26 0.16 V.22 D.J9 0.80 1.48
"~X 4.84 7.69 0.7J 1,05 1.85 7.05 8.09
Mis 2.J9 1.61 0.14 D.lO 0.J8 J.16 J.n
77 J AV ).17 2.18 0.4) U.61 1.07 4.0J 4.38 7£ i'~
::n l!.86 11.)11 0.)2 0.45 0.75 1.24 -1.69
M4X 6.14 J.29 1.Jl 1.86 J.08 7.J6 9.46
Mll~ 2.0) 1.61 0.09 0.12 0.21 2.15 1.19
J.ly 3.<111 2.42 0.67 0.94 1.6) 4.41 5.21
$ 0.5J 0.J7 0.79 0.41 0.68 0.67 1.01
M4X 4.59 J.O' 1.26 1.78 2.80 5.76 7.16
MIN 7.17 1.6d 0.17 0.24 0.'8 2.51 2.0J
117
TABLE 12 conti nued
·78 11 ltV J.ZIl 2.J) 0.50 0.70 1.21 4.12 1t,71 Be 7
9J 0.5J 0.28 0.25 0.J5 0.61 0.71 1.2J
MAA 4.18 2.86 1.07 1.502.475.527.61
Mi,\ 2.28 1.84 0.21 0.29 0.45 2.55 2./.14
lJy 2.7(; ?O/' iJ.22 0.31 '.5/' 3.6J 3.68
SlJ 0.51 'J.?7 '].12 0.17 O.JO G.BII 1.J5
.\:'," !.Ab 2.67 ~.!i" :)./') 1.71 5.0~ 5.76
,v,li. 1.94 1.47 0.12 0.16 0.25 2.JA 1.38
78 12
79
RV 2.7J 2.09 0.)1 0.4) 0.75 3.29 J.B5 0':) 9
3:J 0.42 0.2J <).12 0.J6 0.28 0.6J 1.4J
MX J.51 2.45 O.W 0.84 1.J8 4.60 7.28
ML'''' 1.97 1.6) O.H D.?l 0.)5 2.17 1,7J
AV ).52 2.tiB n.7U 0.99 1.70 4.48 5.10 80 lJ
;JJ 0.7) 0.40 0.44 0.6) 1.11 0.97 1.J6
MJ1' 5.00 ).4J 1.66 2.J6 4.70 6.29 8.50
Mlr-. /..38 1.90 0.19 0.27 0.4) 2.75 2.64
AV J.06 2.2J 0.41 0.58 1.01 J.88 4.57
::n 0.69 U.Jl U.'2O 0.29 0.51 0.61 1.J6
!>V1X 4.07 2.68 0.8& 1.24 2.2) 5.05 7.19
M1' 2.26 1.76 0.17 0.2) 0.47 2.76 2.J1
JIV J.lO 2.17 U.JfJ 0.52 0.95 4.01 4.30
y) U.6J 0.10 V.13 0.19 0.38 0.80 1.140
MIiX 6.04 2.57 0.70 0.98 1.65 6.96 7.GO
MIN 2.13 1.76 0.18 (;.24 0.39 2.44 2.35
79 2 .W 3.17 2.16 0.n8 0.68 1.17 4.2) 5.02 80 11
;JJ 0.6J 0.27 0.J8 0.26 0.45 1.02 1.42
,Y,/l;,\ 5.75 2.74 0.89 1.28 2.10 8.78 8.52
;\'lIN '.19 1.UI v.n D.J1 0.50 2.7) 1.87
"V ).J6 2.29 0.44 0.62 1.06 ).97 4.24
50 0.45 0.2J 0.19 0.27 0.51 0.68 1.22
M~,'( 6.47 2.92 1.10 1.50 J.19 5.6J 7.25
MIN 2.J1 1.86 0.24 O.J) 0.56 2.62 2.41
AV J.J9 2.24 0.41 0.57 1.0J 4.0J •. J5
3:J 0.69 0.26 0.26 0.J7 0.58 0.70 1.03
~AX 5.72 2.84 1.04 1.48 2.4) 5.47 6.89
MIN 2.48 1.68 0.08 0.11 0.19 ).01 2.22
AV J.85 2.24 0.2) 0.)2 0.60 4.JO 4.57
3:J 1.2J 0.27 0.08 0.12 0.20 1.05 0.9)
MJ1X 6.69 2.91 0.46 0.66 1.11 5.81 6.1)
MJN 2.04 1.68 0.09 O.lJ 0.22 2.48 1.68
Av 2.99 2.14 0.42 0.59 1.0) ).96 4.85
!D 0.44 0.29 0.26 0.J7 0.61 0.64 1.4&
MIlX 4.08 2.7) 1.08 1.52 2.56 5.60 8.14
M1.' 2.34 1.56 0.15 0.2J 0.40 2.9J 2.41
Av ).00 2.20 0.4J 0.61 1.08 J.89 4.79
9J 0.50 0.26 0.22 0.J1 9.56 U.82 1.52
MAX 4.17 2.67 0.98 1.41 2.68 6.06 9.51
M1N 2.07 1.69 0.14 0.20 O.JJ 2.29 2.28
AV 2.78 2.1J 0.J9 0.55 0.98 ).50 ).87
;n . 0.51 0.27 0.2) O.J) 0.56 0.75 1.27
MAX J.97 2.66 0.90 1.25 2.2) 1,.97 5.72
MIN 2.1) 1.57 0.10 0.14 0.24 2.J5 0.06
AV J.47 2./l.1 0.56 0.78 1.31 4.1\6 5.16 81 J
XJ 0.J9 0.25 0.22 \1.31 0.51 0.57 1.1)4
MH~ 6.d5 J.a~ 1.19 1.7U 2.77 5.68 8.7.3
/<1/1', 2.65 1.6~ (i.18 0.25 [..35 3.15 2.81
Av 3.50 2.42 0.49 v.7(, 1.16 4.5J 5.21 81 4
Y.J 0.J6 0.22 0.20 0.2& 0.'8 0.55 1.2J
htx h.35 ).02 1.05 1.50 2.52 5.58 8.58
Mli'v 2.77 1.67 0.16 0.23 0.37 ).04 3.13
79 J "y J./j9 2.18 0.49 U.7!; l.le ,L08 5.C:2 80 12
)0 1),-$1 U.JJ !J.J2 :.1.45 U.7.1 j.9G ~.?l
,\I/li( 5.46 J.J.? 1.94 2.76 -1.58 7.12 7.77
f'lI:\ 2.17 1.';6 O.l() v.1J 0.28 2.70 2.ll
79 " AV J.16 2.26 !J.50 CJ.70 1.20 4.03 11.48 81
;JJ 0.45 0.25 0.2) 0.J2 0.56 0.66 1.54
MIlX 4.19 2.93 '.11 1.5fj 2.81 5.21 9.7)
MIll; 2.112 1.83 u.lG G.D 0.22 2.93 0.36
AV ).)1 2.)6 0,4.9 0.69 1.19 /j.n 4.98 81 2
!D 0.47 0.27 0.25 0.J5 0.61 0.70 1.15
>V1X 4.Jl 2.&2 0.9J 1.J2 2.2G 6.JJ 7.0J
k1.\· .?14 1.75 0.1'2 0.18 0.32 2.58 1.76
79 7
79 6
79 5
79 6
79 9
{tV J.J6 2.29 0.)2 0.45 0.79 4.J7 5.2J 81 5
~ 0.59 0.29 0.21 0.29 0.51 0.98 1.82
~"A 4.85 2.96 0.90 1.27 2.3J 6.7J 9.02
Mn 2.41 1.66 0.08 0.11 0.22 2.74 2.0J
Av J.4) 2.1.12 0.d7 0.66 1.15 4.39 5.11 81 6
9J 0.41 0.27 0.22 O.Jl 3.55 0.57 1.25
~.\ 1,.87 2.93 0.95 1.35 2.27 6.71 7.87
Ml.\ 2.511 1.780.150.210.363.152.69
AY J.07 2.24 0.47 0.66 1.17 3.95 4.91l
YJ 0.42 0.28 0.25 0.35 0.64 0.55 I.J9
MIlX J.99 2.72 1.00 1.41 2.52 5.12 9.1H
M1' 2.JO 1.54 0.10 0.15 0.29 2.7' 2.4J
AV 2.56 1.94 0.21 0.29 0.55 J.27 4.1&
!'iJ O.)J 0.21 0.10 0.14 0.25 0.58 1.52
Mil>: J.48 2.Jl 0.45 0.63 1.22 4.76 9.67
MIN 1.96 1.48 0.07 0.09 0.16 2.19 1.)6
4.90
0.82
7.68
J.02
5.14
1.01
6.88
2.J8
11.68
1. 73
7.J9
l.e2
5.92
1.49
8.<1,J
).JJ
4.45
(;. 77
5.72
2.J5
4. J6
0.52
5.21
2.98
4.56
0.64
6.06
J. J5
J.56
0.80
5.21
2J)1j
1.J9
C.49
).21
0.47
1.49
0.68
J.15
J.38
1.15
0.47
2.lI2
0.'7
0.7)
0 . .61;
2.15
c.n
0.60
0.25
1.)7
0.27
0.67
0.28
1.4J
0.27
0.Al
a.14
1.2G
C.12
0.57
0.18
0.97
0.19
u.62 D.cl'!
C.29 0.4J
1.22 1.7/0
0.15 - U.21
u.48
0.19
1.01
u.2!l
f) .19
0.17
U.85
0.06
2.37
0.21
2.78
1.64
2.46
0.29
2.98
1. 74
2.J5
0.21
2.%
1.82
2,fJ7
0.29
2.76
1.5C
J.24
0.J6
4.07
2.27
2.79
O.lIB
.1.69
1. 9J
).46
0.5'
4.6J
2.17
J.4)
0.42
4.J6
2.J8
ltV
!'iJ
MAX
kJ,''I
9
7
10
51
8J
I1J
81
4.22
1. Jl
7.4J
2.61
4.48
l.?d
7.15
2.02
4.55
1. 18
7.04
2.5J
4.75
1.29
8.17
2.90
J.76
0.71
6.D
2.45
4.11
0.55
5.24
2.99
J.96
0.59
5.74
2.66
4.05
0.5)
5.37
2.75
0.86
0.50
2.95
0.J1
1.01
0.47
2.11
a.46
a.96
0.40
2. J(;
0.J4
1.0)
0.54
2.Al
0.)2
0.49
0.27
1.72
0.2G
0.60
0.32
1.45
0.16
0.56
0.24
1.1\2
0.22
0.59
0.27
1.J2
0.26
0.40
0.17
1.0J
0.16
0.4)
0.2J
1.05
0.12
V. J5
0.19
1. 25
0.15
a.A]
0.19
0.95
C.18
2.20
O. JJ
).36
1.65
2. Jij
0.24
2.96
1.82
2.26
0.24
2.76
1.80
2.JJ
0.27
2.9)
1.67
J .26
0.J8
4.22
2.47
J.OJ
0.'6
4.87
2.D
J.22
0.39
<1.16
2.J8
). J8
O. )I;
4.21
2.2'1
"v
~
MJ1X
Mlfv
.V
3:J
AAA
MIN
79 11
79 17
&0
80 2
8u 6
Av J.55 2.25 0.49 0.69 1.11 4.56 4.92 6J 11
9J 0.58 0.25 0.)4 0.49 0.70 0.79 1.21
/01<' 5.90 2.67 1.9J 2.65 J.05 6.54 7.91
Ml"~ 2.118 1.70 0.13 C.18 D.W 2.93 2.92
11Y 3.26 2.J/,) 0.4J 0.61 1.06 4.28 4.98 81 12
!D 0.46 0.22 0.20 0.29 0.50 0.78 1.JJ
Mi.' A.n 2.62 0.85 1.21 2.16 6.11 7.56
1011.'. 2.19 1.74 O.lJ 0.19 O.JJ 2.5) 2.21
AV 2.91 2.17 0.J8 0.5) 0.92 J.71 4.70
;JJ 0.46 0.27 0.21 0.29 0.5J 0.70 1.7)
MAX 4.08 2.96 1.07 1.5J 2.77 5.)J 8.JO
MiN 2.00 1.67 0.16 0.22 0.37 2.J2 1.89
IlV 2.70 2.10 0.31 0 . .64 0.79 3.J8 '.74
!D O.JJ 0.20 0.11 0.15 0.27 0.54 1.14
~AX J.)5 2.51 0.58 0.8J 1.57 4.90 8.79
~J' 2.0) 1.6J 0.15 0.21 O.J) 2.J4 1.70
118
81 Av 2.94 2.01, 0.19 D.?? 0.45 n.O.5 5.90 83 6
:lJ D.~ 0.24 0.Lo3 'J.OJ 0.06 0.J6 0.38
NJ.lA .J.J6 2.31 0.22 O.JO 0.49 4.4J 6.25
Mlh 1.61 1.85 0.17 0.14 0.)8 J.n 5.50
81 1 AV 1.96 l.n 0.4? 0.59 1.01 J.69 4.)1 8J 7
!JJ O.IM 0.26 0.21 0.29 0.52 0.60 1.21
MIlX 4.01 1.89 1.00 1.41 1.56 4.98 8.17
MI' 1.G< 1.7e 0.15 0.21 O.Jl 1.J6 1.06
82 J "V ).ll 1.JJ 0.54 0.76 I.J1 4.06 4.7u 8J 8
g) 0.5. D.JO 0.16 0.)7 0.65 0.75 1.1J
MIIX 4.11 1.9J I.IJ 1.6G J.40 5.41 7.89
M1i'. 2.')1 1.7(; 0.10 D.D v.n 2.D 2.04
81 d !<V J.59 1.5U 0.68 0.96 1.61 4.58 5.ll 8J 9
lV 0.45 0.16 0.15 0.)5 0.59 0.59 0.85
""X 4.51 ).08 1.15 1.77 J.45 5.61 6.79
MIN 1.18 1.61 0.15 0.21 0.J7 1.85 1.69
AV J.57 2.74 0.44 0.61 1.08 4.J" 5.11
lV 0.55 D.J5 0.26 D.J6 0.66 0.6J 1.66
>II1X 4.81 J.49 1.2J 1.7J J.26 6.59 9.6J
MIN 2.15 1.75 0.05 0.07 0.12 2.14 1.72
AV 3 •.58 2.82 0.46 0.65 1.10 4.Jl 1t.1JlJ
SJ 0.41 0.26 D.lO 0.29 0.49 0.65 1.06
MIlX 4.40 J.J8 0.91 1.28 1.14 6.16 7.94
MIN 2.J7 1.89 0.07 0.10 0.17 2.46 2.41
AV J.76 2.90 0.52 0.72 1.24 4.56 5.19
lV 0.5J 0.J2 0.28 0.40 0.68 0.79 I.J4
MIlX 4.95 J .•9 1.14 1.61 2.92 6.79 8.90
MIN 2.55 2.1O 0.11 0.15 0.21 2.69 2.09
Av J.59 2.76 0.42 0.58 1.01 4.J7 4.99
50 0.48 O.Jl 0.26 0.J6 0.62 0.65 1.4J
MAX 4.77 J.57 1.22 1.71 J.D6 5.80 7.90
MIN 2.n 2.0& 0.11 0.16 0.26 J.18 2.55
6Z ? I1V J.17 2.33 O.di$ O.6tj 1.15 4.07 4.91 84 2
Y.J u.5? a.32 0.24 0.34 0.57 fJ.69 1.41
~AX 4.)6 J.12 1.09 1.55 2.5) 5.)7 8.05
!'oil.\ 2.C~ 1.71 0.18 0.2d D.4o 2.31 1.90
81
81
81
81
5
6
7
8
AV
g)
MIlX
MIN
AV
lV
MIlX
MIN
J.Jl
0.41
4.J7
1. ?1
-; .C2
0.51
4.21
1.91
).05
0.47
J.91
2.06
).78
0.J8
4.77
1.86
1.)9
D.2J
J.05
1.69
1.?J
a.31
J.09
1.57
1.U
0.26
2.7J
1.66
1.67
o.n
J.26
1.11
0.51
o.n
1.18
0.16
0.J7
0.2J
1.11
0.07
0.45
0.17
0.77
0.18
0.81
0.20
1.21
D. JO
D.7J
O.Jl
1.81
D.ll
0.5J
D. )2
1.60
0.09
0.64
0.24
1.09
0.15
1. 15
0.19
1. 70
0.4J
1.17
0.58
J.n
0.J8
0.92
0.54
1.69
0.18
1. 11
0.42
1.94
0.41
1. 95
0.51
2.88
0.79
4.11
0.56
5.67
1.77
J.82
0.80
5.ll
1.9)
4.01
0.65
5.n
1.61
4.90
0.46
6.Jl
J.84
4.84
0.91
7.n
1.55
4.55
1.55
9.86
142
4.n
0.99
6.JJ
2.70
5.61
0.67
7.12
J.)4
8J 10
8J 11
8) 11
84 , 1
A\I 3.34 2.7D 0.4u 0.56 0.98 3.94 4.42
lV D.J8 0.16 0.16 G.2) 0 .•0 0.54 1.19
MIl>:: 4.J3 3.)'4 0.91 1.26 2.J5 5.55 8JJl
"'1!'1 2.YI 2JJU 0.13 0.19 0.35 2.99 2.JI,
AV J.27 2.67 !.I./d J.5~ 1.02 3.b'/; 4.16
.2J 0.41 0.27 0.18 0.26 D.4J V.59 l.n
P;'I~ "'.J" J.28 1.00 1.41 2.42 5.38 8,f12
MIN 2.57 2.09 0.15 o.n 0.45 2.81 2.15
AV J.7J 1.95 0.59 0.82 1.42 4.42 4.84
5/.) 0.50 0.29 0.18 0.J9 0.68 O.7J 1.00
MIlX 4.86 J.68 1.J2 1.84 4.0J 5.9J 7.08
MIN l.7J 2.ll 0.19 0.27 0.46 2.9J 2.95
~V J.28 2.65 D.J4 0.48 0.86 J.82 4.10
~ 0.40 0.25 0.14 0.19 O.JJ 0.67 1.27
MIlX 4.J2 J.2J 0.72 1.00 1. 7J 6.DJ 8.16
MIN 1.16 1.05 0.10 0.14 0.2J 1.38 1.17
AV J.64 2.86 0.55 0.77 1.JJ 4.J7 4.92
lV D.4J 0.26 0.2J 0.J2 0.56 0.61 1.10
MIIX 4.66 J.45 1.17 1.65 J.14 6.07 8.76
MIN 2.86 2.J9 u.13 0.18 0 . .36 J.07 1.81
82 E;
lP 1J
81 12
8J
8J 1
8J J
8J 4
8J 5
J1V 2.95 2.2f1 D.1l1; u.5'S :J.98 J.81 4.31 84 3
5/.) O.fJll !'J.7'.J n.17 D.2t. D.43 a.70 1.33
N~~ J.79 7.64 0.85 1.18 2.14 5.46 7.80
Mi" 2.21 1.76 v.IS 0.26 0.46 2.61 2.18
AV ).IJ 1.H 0.50 0.71 I.lJ 4.07 4.71 84 4
YJ 0.5) 0.)1 0.18 0.39 0.65 0.68 1.26
MAX 4.31 2.91 1.13 1.60 2.61 5.46 7.44
Ml1'. 2.24 1.79 0.19 0.27 a.45 1.79 0.66
J.lV J.ll1 2.5J U.40 0.56 0.98 J.77 4.16 Btl 5
~ 0.55 0.46 0.20 0.28 G.1t6 v.63 0.88
/01.11): 01.4& 3.49 1.11 1.56 2.71 5.J4 6.63
MIN 1.20 1.&1 0.15 0.20 0.29 1.65 1.J8
AV J.69 2.9) 0.50 U.69 1.19 4.37 4.83 0:: 6
YJ 0.48 O.Jl D.n O.H D.5J 0.66 1.15
W4A 4.77 3.75 1.05 1.49 2.61 5.64 6.21
M], 2.50 2.26 0.14 0.19 0.29 2.6J 0.20
AV ).71 1.92 0.55 0.77 I.J5 4.45 5.04 84 7
lV 0.42 0.24 D.2J O.JJ 0.5& 0.60 1.17
MAx 4.70 J.51 1.17 1.65 2.91 5.61 8.2J
MII\ 2.85 1.42 0.17 G.74 0.J9 3.17 1.63
AV J.J6 1.72 0.42 u.56 1.01 ).96 4.J5 64 8
5/.) 0.56 O.JJ 0.24 0.)4 0.59 0.86 1..3
MAX 4.48 J.JJ 0.99 I.J8 2.4J 6.09 8.17
MIN 2.31 2.06 0.08 0.11 0.19 2.1l7 2.15
AV 3.46 2.79 0.45 D.62 1.07 4.G8 4.52 84 9
5/.) 0.44 0.26 0.21 0.29 0.50 0.6J 0.98
MAX 4.44 J.28 0.92 1. 3D 2.5J 5.69 6.90
MIN 2.016 1.87 0.11 0.15 0.14 2.77 2.46
AV J.57 1.77 0.48 0.67 1. 15 d.)6 4.96 84 10
lV 0.48 D.2J 0.19 0.27 0.4J 0.78 1.41
MAX 4.86 J.27 1.00 1.)9 2.6) 6.17 8.25
MIN 2.55 1.24 0.14 0.20 D.J5 1.69 1.J7
119
AV J.o1e 2.78 G.48 0.67 1.17 4.13 4.64
lV 0.57 0.)7 D.JO 0.42 0.72 0.77 1.24
","X 4.65 J.61 1.1O 1.68 2.99 5.77 7.95
M],v 2.5U 2.01 0.12 0.17 O.JJ 2.7J 2.14
AV J.63 2.87 0.55 0.77 1.48 4.J6 4.91
~ 0.54 D.J5 0.28 0.J9 u.94 0.76 1.26
MI,X 4.8J J.58 1.22 1.69 7.00 6.04 8.96
MI" 2.29 1.86 0.08 0.10 0.29 2.40 1.01
Av J.70 l.n 0.59 0.8J 1.44 4.44 5.01
SO 0.J6 D.2J 0.21 O.JO 0.54 0.49 0.66
AAA 4.46 3.015 1.16 1.63 3.15 5.48 6.J8
Mji'1 2.91 2.65 0.17 0.24 0.42 3.29 2.96
Av J.71 2.89 0.54 0.76 1. 31 4.47 5.08
5/.) 0.48 0.28 0.24 0.J4 a.S4 0.68 1.14
WOe 4.55 3.i19 1.0J 1.014 2.37 5.68 8.66
MIN 2.55 2.14 0.14 0.1O 0.47 2.96 2.JJ
Ay J.46 2.7J 0.40 0.56 1.00 4.15 4.44
5D 0.64 0.29 0.19 0.27 0.48 0.89 1.06
MAX 7.88 J.92 0.91 1.27 1.19 9.72 6.89
MIN 2.J2 2.09 0.12 0.16 0.29 2.44 1.99
AV J.42 2.7J O.JJ 0.46 D.8J 4.02 4.40
5LJ 0.42 0.29 0.18 0.15 0.45 0.61 I.JJ.
MAX 4.4J J.51 D.8J 1.17 2.20 5.41 8.16
MIN 2.46 2.IJ 0.10 0.14 0.29 2.51 1.26
Av J.I6 2.56 0.19 0.40 0.76 J.64 4.16
5I.J 0.)9 0.18 0.17 0.24 0.44 0.54 1.40
MI,X 4.62 J.41 LJl 1.55 2.42 5.46 8.JJ
MIN 2.51) 2.08 0.11 0.16 O.JO 2.60 2.02
AV 3.50 1.BO 0.46 0.64 1.15 4.07 4.46
5I.J 0.58 0.40 0.19 0.41 0.71 0.72 1.18
~~~ 4.98 3.9J 1.31 1.84 3.017 5.80 7.98
Ml' 1.65 1.07 0.16 0.11 0.)8 1.86 2.1O
TABLE 12 continued
811 11
85
II\' J.54 7.86 U.~2 t'.72 1.35 I1.W 11.56 86 .5
:JJ 1.(..7 ::.1.6 0.36 0.51 J.9? U.86 1.76
.\fIJI 5.}.£; 4JU l.~t: J.n ).67 6.39 8.J~
.... 1>. 7.S} 7.1'J 0.15 n.71 0."') J.n ?SJ
IlV .1.2/ 2.1>! :J.J8 D.5} 1.00 J.86 II.Jl 86 6
ju ti.4S 0.78 v.n V.l} 0.61 (J.76 l.J'l
M1U ""115 3.31 1.17 1.<S~- J.lJ 5.81 B.II)
f-;J'\ J.n 1.811 .~.14 u.2fJ lJ.lIlJ l.dB 1.91
~v J.61; 7.71. c.SO 0.70 l.V d.ll 11.67 86 7
!JJ G.52 0.31 0.77 0.19 ll.63 0.71 1.35
"';IA 5.1):: ).68 1.6'> 2.05 3.56 6.01 8.94
Mlf1f 2.47 2.01 [J.l} 0.21 lJ.J9 lJj6 1.96
,11" J.24 2.41 0.47 .0.65 1.12 1l.07 01.81
5u 0.44 0.27 0.21 o.n 0.57 0.60 I.J7
MAX 4.J2 J.06 1.09 1.54 J.22 5.52 9.57
MJ,., 2.J5 1.79 0.16 0.22 0.)8 2.69 0.J9
AV J.26 2.41 0.46 0.65 1.10 4.1. 5.00
50 0.5J O.JJ 0.27 0.J8 0.65 0.78 J.48
Mil. 4.41 J.12 1.15 1.6J J.OO 5.61 9.87
MIN 2.00 1.61 0.08 0.12 0.16 2.)0 1.76
AV J.41 2.51 0.48 0.68 1.16 4.J2 5.H
50 O.J) 0.22 0.19 0.28 0.49 0.50 1.15
MQX 4.21 2.97 0.9J 1.JJ 2.48 5.59 7.94
MIN 2.60 1.82 0.17 0.24 0.40 J.20 2.46
d5
85
2
J
J.57
t1.~J
4.39
2.6"
J ••9
0 ••5
•. 55
1.71
7.87
fi.29
).47
2.06
2.74
1j.77
J .•2
'}.2.l
(j.50;
0.2)
1.08
O. JJ
0, }/j
0.2.
l.CJ4
0.16
0.82
li.JJ
1.5J
L15
0.75
O.J.
1.4;
(J.7)
1.47
G,57
2.81
O.J.
l.JJ
0.59
2.79
0.J9
4.17
0.57
5.1d
2.85
4.18
0.65
5.8&
J.09
4.68
0.99
6.20
2.J4
4.65
1.18
7.00
2.115
86
86
8
9
AV J.26 2.44
SJ 0.60' 0.16
HAX· 5.19 J.J9
MIN .1. ro '1.47
J.04 2.28
0.66 0.16
4.J7 J.06
2.00 1.68
'0 ••1
0.20
1.16'
0.09
0.41
0.25
1.04
0.09
0.57 0.96 4.08
0.29 0.47 0.86
1.64 2.71 6.45
O.lJ 0.20 1.8J
0.57 0.99 J.81
0.J5 0.59 0.98
1.49 2.5J· 5.9J
0.12· 0.22 2.10
4.75
1.4J
·7,45
1.J5
4.5J
1.70
9.56
1.50
85 4 AV J.47 2.68 0.51 0.72 1.25 4.J7 4.52 86 10
~ 0.59 0.J6 0.27 0.)6 0.6J 0.85 1.J6
,..JlJl 5.86 ).48 1.2) 1.76 2.89 7.67 7.09
f-lll'Y 2.40 1.90 O.D 0.18 0.)'2 2.6U 0.67
AV 2.65 2.06 0.26 0.16 0.6J J.31 4.32
so 0.37 0.20 0.09 0.1) 0.22 0.64 1.76
MAX 4.J5 J.OJ 0.49 0.68 1.09 4.98 8.7J
MIN 1.75 1.5. 0.08 0.11 0.21 '1.85 1 ..56
/lV J.81 2.90 0.65 0.91 1.56 4.69 5. J8 86 JJ
So, 0.J8 0.22 0.20 0.28 0 .•7 0.56 0.98
MIl)l; 4.5.l J.J5 1.17 1.56 2.81 5.8) 8.40
Mlr-v 2.91l 2.41l 0.21 0.31 0.6) J.tl2 J.27
Av J.62 2.80 0.58 0.81 1..0 4.J8 5.0. 86 12
So> 0 .•8 0.29 0.21 0.J2 0.57 0.69 1.09
MIl), -1.49 ).J4 1.01 1.40 2.8) 5.55 7.05
MI' 2.76 2.20 0.16 0.21 0 .•• J.04 2.65
AV J.52 2.72 0.51 0.72 1.27 4.25 4.75 87
~ 0.6J 0.J5 0.25 0.J5 0.60 0.9J 1.16
/o<Il' •• 52 J.48 1.05 1.48 2.5. 5.72 8.6J
MIN 2.29 1.99 O.l) 0.17 0.40 2.40 2.J7
AV 2.80 2.fJ9 0.J6 0.51 0.94 J.45 •. 00 87 2
5u 0.55 O.JJ 0.26 0.)8 0.68 0.75 1.64
MJ4A 4 . .36 ).06 1.26 1.76 ).36 5.42 8.JO
Ml.\ 2.12 1.62 0.16 0.21 0.4J 2.J8 0.99
85 5
85 6
85 7
85 9
85 11
85 II
86
AV 3.47 2.5) 0.67 0.94 1.6J 4.J2
5u 0.7J 0 ..4 0.J5 0.49 0.81 0.96
MlIJl 5.1u 3.62 J .46 1.01 J.40 5.9)
/of!:\ 1.27 1.79 D.ll -0.29 0.55 2.69
Av 2.95 2.J9 O.•J 0.60 1.07 J.66
S,) 0 .•8 0.27 0.20 0.29 0.50 0.71
MIIx 4.01 2.90 1.04 1.46 2.99 5.50
Iotl." 1.87 1.59 O.H U.21 0.40 2.01
AV 2.6J 2.06 0.J5 0.49 0.86 J.21
5u 0.26 0.J9 0.10 O.l) 0.2J 0.J5
MIIX J.27 2.48 0.66 0.9J 1.76 4.08
NJi''1 2.07 1.66 0.J6 0.21 0.47 1.J5
~v J.t>9 2.IlJ U.611 (j.8S lA8 01.10
5u 0.64 0.J6 0.28 0.40 0.68 0.89
MQX 4.62 J.H 1.26 1.76 J.16 6.J6
MlN 1.99 1.62 0.15 0.22 0.46 2.24
4.88
I.J9
9.28
2.J7
4.22
1.29
8.20
1.4J
J.60
0.68
5.88
2.J9
01.61
1.18
6.95
2.26
87
87
&7
87
J
•
5
6
AV 2.70 2.05 0.27 0.J7 0.66 3.44 4.71
50 0.45 0.20 0.09 O.JJ 0.24 0.86 2.19
MAX 4.8J 2.89 0.56 0.80 1.41 7.25 9.26
MIN 1.61 1.37 0.06 0.09 0.16 1.61 ·1.J5
AV 2.68 2.08 0.29 0.40 0.70 3.16 4,49
S,) 0.J1 0.J6 0.09 O.H 0.2J 0.59 2.02
MIIx 3.59 2.47 0.68 0.97 1.85 4.88 9.98
MIN 2.09 1.74 O.H 0.18 O.Jl 2.)0 2.15
AV 2.46 2.0. 0.24 0.3J 0.58 2.89 J.12
5u 0.24 0.15 0.06 0.09 0.15 0.J7 0.65
Mil' 3.52 2.54 0.45 0.6. 1.00 4.19 5.34
Ml' 2.00 1.7J O.H 0.18 0.)0 2.19 1.56
AV 2.88 2.18 0.J4 0.48 0.84 3.66 4.47
5u 0.42 0.21 0.15 0.21 0.J6 O.7J 2.10
MAX 4.08 2.94 0.90 1.29 2.15 5.55 9.76
MI' 2.J6 1.69 0.11 0.16 0.28 2.Jl 0.J2
AV 2.75 2.11 0.27 0.)8 0.65 J.49 4.44
.so 0.40 0.17 0.09 0.12 0.21 0.76 1.86
MIIX ••09 2.68 0.60 0.8. 1.4J 5.65 8.02
Ml' 2.10 1.69 0.12 0.17 0.28 2.24 1.56
IlV J.19 2.28 0.42 0.59 1.01 4.21 5.59
~ 0.52 0.28 0.21 O.JO 0.52 0.8J 2.17
MilX 4.84 J.14 J.OJ 1 ••4 2.82 6.JJ 9.80
/oU,., 2.0.1 1.76 0.01 0.02 O.OJ 2.15 0.05
I1V ).4U 1.47 0.51 0.72 1.14 4.)" 5.15
5u 0.4J 0.27 0.21 O.JO 0.54 0.60 1.11
,..,x 4.55 J.lO I. OJ 1.46 J.07 5.9J 9.09
MIN 2.15 1.6~ 0.11 0.16 O.JJ 2.68 2.61
Ilv ).46 2.51 0.54 0.76 1.)1 4.39 5.21
'" 1).46 0.21 O.V 0.)2 0.58 0.70 1.16
!"~A 4.46 J.14 L?J 1.7U J.7u 6.20 7.8J
MJ.\ 'l.Jb 1.7'..; ('.13 0.19 G.Jl 2.79 2.J5
86 2
86 J
86 4
}IV J.Ol 2.Jl 0.44 0.61 1.07 ).69 4,15 t.; i
5u 0.64 0.J6 O.JJ 0 .•6 0.8J 0.84 1.2J
Ml<X 5.20 J.5J 1.74 2.50 •. 95 6.86 7.J6
MI' 7.0~ 1.64 0.11 0.J6 O.JO 2.29 2.17
/IV J.62 2.6J 0.70 0.99 1.71 4.55 5.14 d7 8
so 0 .•7 0.26 0.22 0.J2 0.58 0.65 0.96
Mil" 4.55 J.1J 1.27 1.80 J.D 5.79 7.2)
MIN 2.J6 1.88 0.17 0.25 O.•J 2.64 2.28
Av J.58 2.59 0.6J 0.89 1.52 •. 57 5.2J 87 9
:v 0.J7 0.21 0.19 0.27 0 .•8 0.5J 0.8J
"'AJl 4.1l9 J.07 1.15 1.6J 2.84 6.22 8.76
NUl,- 7.61l 2.OC 0.23 0.3J 0.56 3.J2 2.68
120
Ilv J.31 2.Jti v.o1l U.59 L(jl 1•. 27 5.14
~ D.4ti 0.28 0.24 U.JI1 0.6J 0.71 1.26
" ... A 01.}o5 3.J2 1.19 1.69 4.02 6.15 8.n
,v,1;, 2.15 L6b 0.09 0.1.1 0.20 1.45 1.95
Ilv J.16 2.J5 0.J9 0.5. 0.9J J.98 •. 62
so 0.50 0.31 0.21 0.)(; 0.50 0.75 1.50
p~x 4.49 J.J5 1.08 1.47 2.70·5.49 8.16
MIN 1.91 1.62 0.12 0.17 0.29 2.09 1.66
AV J.47 2.51 0.5J 0.72 1.25 •. 40 5.12
~ 0.51 0.28 0.26 0.J6 0.65··0.11 1.25
MQX ·4.8J J.24 1.21 1.72·2.·95 5.71 7.87
MIN 2.19 1.78 0.11 0.16 0,26 '·2.52 2.17
TABLE 12 continued
87 10 Av J.OJ 2.J3 0.41 0.57 1.01 J.76 ~.J2
5lJ 0.44 0.26 0.2& 0.28 0.51 0.60 1.25
,..., 4.52 J.15 1.26 1.77 3.09 5.71 7.27
1011" 2.28 1.8u 0.17 0.2~ 0.41 2.59 2.17
87 II .v 2.99 2.32 0.~2 0.59 1.05 J.68 4.lJ
5lJ 0.401 0.25 0.21 0.29 0.55 0.62 1.09
,,,"X ~.51 J.09 1.J2 1.87 J.87 5.64 7.4J
Ml,'oi 2.10 1.78 0.15 0.22 0.J8 2.J6 2.16
87 12 Av J.19 2.41 0.45 0.6J 1.14 J.98 ~.48
5lJ U.16 0.24 0.17 0.24 0.52 0.52 loll
,..., J.87 2.85 U.87 1.25 J.70 5.17 7.88
Mj,'y 2.10 1.78 0.15 0.21 0.J5 2.72 2.20
Tz
Tc
Hrms
Hsig
Hmax
Ts
Tp
- zero crossing period (sec)
- crest period (sec)
- root mean square wave height (m)
- significant wave height (m)
- maximum recorded wave height (m)
- slgnificant period (sec)
- peak energy period (sec)
121
TABLE 13
Annual Wave Statistics for Wave Buoy near Cape Cleveland.
yeA.H 1>0,\,111 Il Ie hNM) t:Sl\; 1-(....04>.-
"
IP H:"l<ft ,'.f.J,~ I '1 TL Te fIlfol; ttSlG IMX 15 TP
75 12 4v J. 1.1 2.29 G.49 U.119 l.Ztl .1.95 4.5J bJ 12 .v 3.50 2.81 0.50 0.70 1.22 •. 12 4.51
7) V !v 1).5d 0.33 V.l:> O. J5 6.6,/ C,79 LP 81 0 !v 0.51 0.]1 0.25 O. J5 0.60 0.7] 1.16
75 12 ,\~X 4.611 3.31 1. 27 1.80 3.56 5. b'(, 7."0 &J 12 '~X •. 86 ).60 1. J2 1.8. ..03 5.93 8.02
75 12 Mli''1 2.09 1.6.1 (; ,13 O. J3 (j. JlJ 2.42 2.15 81 J2 f,11 ,~ 2.57 2.09 0.15 0.12 0.4.5 2.81 2.15
76 6 .V 3.17 2.25 0.47 0.66 1. 15 4. JIi 4.97 8. 6 IlV J.57 2.bJ 0.51 0.72 1.27 4.24 4.73
76 6 SJ 0.56 0.32 fl.?J 9. JJ 0.5& 0.80 1.42 84 6 SJ 0.50 0.]1 0.25 0.J5 0.65 0.71 1.0
76 6 ~" 4,8) J.Jl 1.27 1.ba ].5& 7.78 9.90 84 6 I4<X •.86 J.68 1.]2 1.8. 7.00 6.07 8.9676 6 ,'il,\ 1. 78 1.48 0.08 0.11 0.19 2.15 0.]4 84 6 /ofl,' 2.29 1.88 0.08 0.10 0.23 2.38 2.01
76 12 .V J.12 2.22 0 .•2 0.59 1.0] •• 0] •. 81 8·1 12 .v ].50 2.78 0••6 0,6. 1.16 .d .16 ..61 .
76 12 9.J 0.53 O. Jl a.'l2 O.Jl 0.54 0.79 1. 47 84 12 .'iJ a.5J 0.J4 0.26 a.J7 0.68 0.74 1.2.
76 12 MIlx 4.83 J.JO 1.23 1. 71f 3.16 7.78 9.90 84 12 MIlX 7.eB 4.02 1.58 2.2J 7.00 9.72 8.96
76 12 /oflN 1. 78 1..8 0.01i 0.11 0.19 1. 91 O. J. 84 12 f>ll,v 2.22 1.&4 0.08 0.10 0.23 2.J8 1. 26
77 6 IlV 3.15 2.26 1).411 0.61 1.06 •. 07 4.68 b5 6 AV ).118 2.75 0.47 0.66 1.19 •• 1] •• 59
77 6 SJ 0.57 0.J7 0.24 a. J5 0.60 0.82 1..0 85 6 9J 0.5. 6. JIi 0.77 0.38 0.65 0.75 1.27
77 6 folQX 6.14 J.3O 1.J2 1.89 3.JO 7.J6 9.46 85 6 "'"X 7.88 4.02 1.58 2.23 J.67 9.72 8.94
77 6 /oflN 1.85 1.52 0.09 0.12 0.71 1. 91 1. 19 85 6 Mli~ 2.22 1.84 0.10 0.14 0.29 2.44 0.67
77 12 AV J.3O 2. J4 0.50 0.70 1.22 4.23 4.92 85 12 IlV J. J5 2.57 0.52 a.7J 1.27 •. 07 4.58
77 12 SJ 0.55 O. Jl 0.25 0.J6 0.62 0.79 1.27 85 12 51 0.62 0 .•2 0.26 0.J7 3.62 0.82 1.30
77 12 /o'AX 6.14 J.29 1.32 1.89 J.3O 7.36 9.46 85 12 "'~L( 5.86 J.6tJ 1.46 2.05 J.56 7.67 9.28
77 12 /1'01.\ 1.9J 1.52 0.09 0.12 0.21 2.1d 1.19 85 0 foll,\ 1.87 1.59 0.11 0.15 0.]2 2.01 0.67
78 6 .v J.JG 2.]5 0.46 0.68 1. 18 4.24 4.91 86 6 "V 3.201 2.41 0.52 !J.7J 1. 27 4.04 4.62
78 6 SJ 0.51 0.29 0.74 0.J4 0.58 0.75 1.23 86 ~ 5J 0.60 0.J6 0.27 a.J9 U.6/ 0.8.J 1. 31
79 6 folQX 5.18 J.26 1.20 1.7J ].0] 6.79 8.12 86 6 MIl' 5.20 J.62 1. 74 2.50 4.95 6.8~ 9.87
75 6 /ofl.\ 2.05 1.56 0.10 0.14 0.23 2.]1 1. 79 86 6 foil,' 1.87 1.59 u.08 0.12 0.16 2.01 0.J9
78 12 .V J.25 2.30 0.116 0.65 l.lJ 4.16 4.78 86 a 4V J.14 2.35 0.45 0.6J 1. f){j J.95 4.74
78 12 .x, 0.55 0.29 0.24 0.34 0.60 0.84 1.30 86 12 !v 0.59 (J.311 0.25 a.J6 0.62 0.85 1.5J
78 12
"'''
5.711 J.76 1.26 1. 78 2.80 9.00 8.09 86 12 ,~x 5.29 J.51 1. 74 2.50 11.95 7.25 9.98
78 12 M[I'1 1. 97 1.54 0.10 0.14 0.23 2.72 1. 7) 86 12 ,.,1,.. 1. 61 1. J7 0.06 0.09 0.16 1.61 0.J9
79 6 "V J.28 2.Jl 0.51 0.7J 1.23 4.23 •• 91 87 6 IlV 2.99 2.25 0.J7 0.52 0.89 ].77 4.65
79 6 SJ 0.55 0.30 0.27 0.38 0.66 0.82 1.30 87 6 SJ 0.56 0.30 0.70 0.28 0."8 0.86 1.77
79 6 MIl, 5.74 J.41 1.94 2.76 4.70 9.00 9.7] 87 6 folQ, 5.29 J.J9 1.20 1. 70 ].70 7.25 9.98
79 6 /011, 1.97 1.5. 0.10 O.lJ 0.22 2.22 0.J6 87 6 foIl,\ 1.6/ 1. J7 0.01 v.02 O.OJ 1.61 0.05
79 12 AV J.3O 2. JJ 0 .•8 0.67 J .15 /L24 •. 92 87 12 .. J .11 7. J7 O./ll 0.57 1.00 3.92 4.65
79 12 9.J 0.51 0.29 0.26 0.J7 0.6] 0.75 l.J5 87 17 3J 0.5J 0.29 G.2J :J.Jt. G.51J 0.60 1. 57
79 12 ~x 5.46 J.41 1.94 2.76 4.70 8.78 9.7J 87 12 MIlX 4.811 J.J5 l.J2 1.87 4.02 6.31 9.80
79 12 /ofl,\ 2.14 1.66 0.08 0.11 0.22 2.58 0.J6 87 12 /oflN 1.91 1.60 0.01 0.02 0.03 2.09 0.05
80 6 .v J.3O 2.Jl 0.42 0.59 1.01 •. 21 •.82
8a 6 SJ 0.1.18 0.27 0.2J 0.J2 0.5J 0.7] l.J6
80 6 ""X 5.90 J.16 1. 91 2.65 J.05 6.7] 9.02
80 6 foil' 2.U 1.65 0.08 0.11 0.22 2••5 2.02
80 12 'v ].21 2.ll 0.1.10 0.57 0.98 '.OJ •• 4280 12 3J C.511 0.26 0.2J O.JJ 0.5J 0.79 1.30
R~ 12
"'''
6.0' ].16 1. 91 2.65 J.19 6.96 7.91 Tz - zero crossing period (sec)
80 17 MI,\ 1.96 1. 47 0.08 0.11 0.19 2.J4 1.38 Tc - crest period (sec)81 6 IlV 3.10 2.18 0.J7 0.57 0.9J J.85 4.42
81 6 !i; 0.69 0.27 0.22 O.Jl 0.5J 0.13 1.J6 Hrms - root mean square wave height (m)
el 6 M" 6.69 2.92 1.10 1. 52 J.19 6.96 9.67 Hsig - significant wave height (m)81 6 Mis 1.94 1.47 0.U7 0.09 0.16 2.19 0.06 Hmax maximum recorded height (m)81 12 'v 3.06 2.20 0.40 0.56 0.99 ].68 4.70 - wave
81 12 3J 0.64 0.29 0.23 O.JJ a.57 0.80 1.46 Ts - slgnificant period (sec)
81 17 ","X 6.69 2.98 1.22 1. 74 J.21 6.08 9.67 Tp - peak energy period (sec)81 12 MJ"f 1. 9J 1. .8 0.07 0.09 a.16 2.06 0.06
82 6 "V J.18 2. JO 0.4d 0.68 1.17 4.04 4.80
82 6 3J 0.5J O. JO 0.25 0.16 0.61 0.77 1.JJ
82 6 folQA 4.6J J.09 1.28 1.82 J.7J 6.08 9.86
87 6 Mlh 1. 91 1. 50 0.07 0.09 0.18 1.9] 1.42
82 12 Av J.25 2.]7 0.52 0.7J 1.26 4.12 4,78
82 12 9J u.511 O. J2 0.26 0.J7 0.6J G.7d 1.19
82 12 /o'{<X 1J.77 3.49 1.28 1.82 J.7J 6. J2 9.86
82 12 NJ,\ 1. 91 1. 57 0.07 0.09 0.18 1.9J 0.66
83 ~ 'v J.4J 2.64 0.49 0.69 1. 19 11.2J. 11.81
8J 6 9J 0.55 0.37 0.25 0.35 0.59 0.75 1.JO
8J 6 "'AX 1J.l!6 .1.75 1.23 1.73 J.26 6.59 9.6J
8' 6 ,'iJ .\ ?.:'t 1.6t' 1).0.') 0.07 (j .J? '). ]/t 1).2tJ
Note: Data is presented both for calendar years ending 31 December
and for dredging years ending 30 June.
122
~
N
W
TABLE 14
WAVE STATISTICS
WAVE PERIOD/WAVE HEIGHT OCCURRENCES
a)ALL DATA, ALL DIRECTIONS
Signifiont Peak Energy Wave Periods (Seconds)
Wave Height Totals
(metres)
0-2.99 3 - 4.99 5 - 6.99 7 - &.99 9 - 10.99 11 - 12.99 13 - 14.99 >14.99
.00 - .20 40.&7 35.50 39.00 19.37 6.25 3.25 .. .. 144.24
.21 - .40 275.95 370.57 242.43 119.&0 6.49 2.75 0.75 .. 101&.74
.41 - •60 61.70 643.74 12&.16 46.41 4.01 1.25 0.50 .. &&5.77
.61 - .&0 1.00 423.09 1&4.27 11.50 1.00 .. .. .. 620.&6
•&1 - 1.00 .. 189.19 283.10 4.75 .. 1.00 .. .. 47&.04
1.0 I - 1.20 .. 73.20 262.49 0.49 0.50 0.50 .. .. 337.1&
1.21 - 1.40 .. 11.51 146.&3 0.50 .. .. .. .. 158.&4
1.41 - 1.60 .. 2.50 66.95 0.75 .. .. .. .. 70.20
1.61 - 1.80 .. 0.50 29.47 0.50 .. .. .. .. 30.47
1.81 - 2.00 .. .. 6.75 .. .. .. .. .. 6.75
2.01 - 2.20 .. .. 2.25 .. .. .. .. .. 2.25
2.21 - 2.40 .. .. 1.50 0.50 .. .. .. .. 2.00
2.41 - 2.60 .. .. .. 0.25 .. .. .. .. 0.25
2.61 - 2.80 .. 0.50 .. 0.50 .. .. .. .. 1.00
TOTALS 379.52 1750.30 1393.20 205.32 18.25 8.75 1.25 0.0 3756.59
Values in the above table are durations in days and have been rounded to the second decimal place.
~
N
..,.
TABLE 14 continued
WAVE STATISTICS
WAVE PERIOD/WAVE HEIGHT OCCURRENCES
b) SUMMER DATA, ALL DIRECTIONS
Significant Peak Energy Wave Period (Seconds)
Wave Height Totals
(metres)
0-2.99 3 - 4.99 5 - 6.99 7 - &.99 9 - 10.99 11 - 12.99 13 - 14.99 ) 14.99
.00 - .20 15.25 18.75 12.50 4.25 3.25 * * * 54.00
.21 - .40 I 15&.15 216.40 112.04 50.65 5.00 2.00 0.25 * 544.49
.41 - .60 42.54 329.76 5&.83 22.26 3.26 1.00 0.50 * 458.15
.61 - .80 0.50 201.17 67.04 5.75 1.00 * * * 275.46
.81 - 1.00 * 99.38 105. I 2 3.75 * 1.00 * * 209.24
1.01 - 1.20 * 43.84 113.6 I 0.25 0.50 0.50 * * 158.70
1.2 I - 1.40 * 7.26 64.7 I 0.50 * * * * 72.47
1.41 - 1.60 * 1.25 39.11 0.50 * * * * 40.86
1.61 - 1.80 * 0.50 18.24 0.25 * * * * 18.99
l.31 - 2.00 * * 5.25 * * * * * 5.25
2.01 - 2.20 * * 2.00 * * * * * 2.00
2.21 - 2.40 * * 1.50 0.50 * * * * 2.00
2.41 - 2.60 * * * 0.25 * * * * 0.25
2.61 - 2.80 * 0.50 * 0.50 * * * * 1.00
i TOTALS 216.44 918.81 599.95 89.40 13.01 4.50 0.75 0.0 ·1842.86
Values in the above tables are durations in days and have been rounded to the second decimal place.
~
N
<.n
TABLE 14 continued
WAVE STATISTICS
WAVE PERIOD/WAVE HEIGHT OCCURRENCES
c) WINTER DATA, ALL DIRECTIONS
Significant Peak Energy Wave Period (Seconds)
Wave Height Totals
(metres)
0-2.99 3 - 4.99 5 - 6.99 7 - &.99 9 - 10.99 11 - 12.99 13 - 14.99 >14.99
.00 - .20 25.62 16.75 26.50 15.13 2.99 3.25 * * 90.24
.21 - .40 117.79 154.16 130.39 69.15 1.50 0.75 0.50 * 474.24
.41 - .60 19.17 313.98 69.33 24.14 0.75 0.25 * * 427.62
.61 - .80 0.50 221.92 117.23 5.75 * * * * 345.40
.81 - 1.00 * 89.82 177.98 1.00 * * * * 268.80
1.01 - 1.20 * 29.36 148.88 0.25 * * * * 178.49
1.21 - 1.40 * 4.25 82.12 * * * * * 86.37
1.41 - 1.60 * 1.25 27.84 0.25 * * * * 29.34
1.61 - 1.80 * * 11.23 0.25 * * * * 11.48
1.81 - 2.00 * * 1.50 * * * * * 1.50
2.01
-
2.20 * * 0.25 * * * * * 0.25
TOTALS 163.08 831.49 793.27 115.92 5.24 4.25 0.50 0.00 1913.73
Values in the above table are durations in days and have been rounded to· the second decimal place.
FIGURES
126
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FIGURE 1 Location map of Townsville and Cleveland Bay area.
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FIGURE 3 View of Harbour showing proposed improvements as adopted by
Townsville Harbour Board. 1897,
129
85 86 87
'Sir Thomas Hiley'
83 84
T.S.D
828180
1965 to February 1983 for S.D. 'Townsville'
Note that additional dredging was carried
79787776
'~I >. (!'CD
~I :f I~
.+ I III r:, Total dredged
CD c
=1 c I~ ------ Dredged from Platypus Channel> E I ~~I 0
~ 0 ,~ -.-. Dredged from Swing Basin~I ,...0 >. t-. I ,. ............. Dredged from Berths~ CD
"'~ :f 1 Dredged from Ross River Channel
<I>
,
CD ,
C ,C
0
-
7170696867 72 73 74 75
S.D. 'Townsville'
Townsville Port Authority annual dredging records September
and July 1983 to August 1988 for T.S.D. 'Sir Thomas Hiley'.
out by 'Sir Thomas Hiley' between 1973 and 1975.
A,,
I '\
I '\
I '\
, '\
, \
, \
I \I \ ~
, \ I \
I \ I \
I \ ' \
I \ I \
I ' ,\
I ' I \
I r I ,
........,' \' I ,
......... , I ,'"''
, \ I \ /" 'I~~~""""" \,' , ';<. \\ , ' • ~~ , • 1\ , ' / I ~J \ '
" 1 I ' ,
", ,.' 1/ '" y " . r' \\ ", \.'
.. .\, / \.,
/
- . /" . "\
.' .:'. 1 ,
.~ ............ . ",:.: ..•.. . \. "~... . :. "j / .
o '. : - .., ••~I •••••••• • \I I \ •••••••••
1965 66 I I I· I - •••.
j I I .......I I I ........
I I I I I j I I I I
"0
C
"'<Il
<IlQ)
:::lc
Oc
-'=0
f--
FIGURE 4
100
200
300
700
500
600
400
""w
o
o I I ' •
1965 1 1966 1967 i 1968 I 1969 i 1970 ' 1971 i 1972 I 1973 1974 I 1975 I 1976 I 1977 i 1978 i 1979 i 1980 i 1981 1982 I 1983
."
C
m •
••, c
o c
~o
~-
120
110
100
90
80
70
60
~
W
~
50
40
"j . IA A
V\ ~ . ~ \(\20 -111 I I I I '\ I U' / ~ j \1
10 ~II /V V 1/ \ in addition dredging
by Hiley
Hiley Hiley Hiley
FIGURE 5 Townsville Port Authority monthly dredging records September 1965 to February 1983 for S.D. 'Townsville'.
Gaps occur when the dredge was being overhauled and repaired.
1-1/6/59
[I) SeagraS$
~ Mangroves o,
/ '.;:'•
km
2,
,-"
".
FIGURE 6 Maps of coastal area between Shelly Beach and Cape Pallarenda
drawn from aerial photographs taken in 1959. 1974, 1981 and 1985.
132
3015114
=-=_--_~.~"'''.~bi'''.
una f1if
f@ful Seag' assBill
~ Mangroves
1516185
I
9
1417181
FIGURE 6 continued
133
, , ,
, km .
,
,
•~ • S
, 0
~....
ttl"
manllrovoe
" ...fIo.
,
,
i -'e &- ,/ I r;."
A 0"'" e 5 //,',/ /..~,/}. I b
,/ I..;s.:t/'i/: ,#
,/ /.... ' "" "b~.. ~'V ....~ 'J.~ ..¥
'<!'v I:>~ .i.'1? <i •
•.,f!'o, •.,f!'/ IV~/;> <1
./ ,/ ~ ..~~~_wal..... ,/ ,/ ...h'n ,and
_ __ ':!:'go ... ", e/"A (/~~-' _ • ./ ... /' ./ _ -" _L).~..,~~",..-~~ ..-
I:lnd t)f,rl
P4l11'''''tJ/I
1516/85
.• ~e
... _~"1!:.. Capo
::::::-~- f>"lIaronda;;;:, ,~....
.~,
-w
~
FIGURE 7 Map of coast between Cape Pallarenda and Ross Creek drawn from aerial photographs taken in 1985
1-716/59
14/6/74
=
~ Mangroves
FIGURE 8 Maps of coast baerial h etween Ro R"p otographs t k ss 1ver and Sa en 1n 1959. 1974andflY• 1981
135
Creek drawn
and 1985.
from
1411/61
1511/65
FIGURE 8 continued
~ Mangroves
136
--------~----
"'"
1941----
1952--------
~
Ci:
(I) //
C3
0:
a
1952----
1959--------
ffi
:>
a: ,.
CI) I~
"'0 ,0(
cr: t.
1959----
1961 --------
~ 0: ,'":> .-Ci:
'"~ '"00:
1961----
1965--------
1965----
1971/72------
900
!
600
,
metres
300
,
\
o
,
..... -
• Erosion
fjj[[~j~ Progradation of sand ridge
mProgradation of Mangrove
1971/72---
1973--------
1941----
1973--------
~
Ci:
'"C3 'i
Q:......
~;;:.
\
FIGURE 9 Shoreline changes in the Ross River to Sandfly Creek area 1941-1973.
After McIntyre and Associates. 1974.
137
301SI74
19'15'S
" ,
1~6'SS'E 1~7'aO'E
\
\
\
\
1
J
/
/
I
I
/
/
J
Imlll
"tid
b,,~h..
C2iD
~
lIagra..
lIagr... wl1h
obllqua lind bart
mlngrov"
lind
from
especially
drawn
Note1985.
147'OO'E
o
..
'1J'If'./
I ~II'II (,~
,~ ....ot>qq,··
''''1 /
I~'I",,
<.,4)),,,,,,.-1----------1
/ .
/
/
I
I
/
1978. 1981 and
of seagrass.
/-
1'\ /y,...,,-~V
, I
~~\l~
, ,
I
I
I
'~
"I ,0'I
,
,,/
___ - -_l...
/ "
/ "
,I
I I
1~6'5S'E
Maps of coast between Sandf1y Creek and Cape Cleveland
aerial photographs taken in 1974,
the changing distribution pattern
FIGURE 10
,
,
,
,
,
,
19'15'S
28/11/18
138
15/7/81
19'15"5
24/6/85
19'15"5
,
\
,
,
'\eli-...J¥4/6:
-"':Z"'~k...."..
\
\
,
,
,
,
,
FIGURE 10, continued
139
\
i
"I,.
0'
\
i::
I:·
0'
"i,
,
,
;~
\:..
\:;.
,<
,.
o
~.
l,
,
~
o
I
f,
,:,.
,
;:-
.,)~'·.';~Y
Crocodile Creek
COASTLINE
1941
1959
1973
NOTE Plans join at corresponding
numbers, approximately
PROGRADATION
I}:::}:n 1941 - 1959
>' 1959 - 1973
EROSION
~ 1941 - 1959
~ 1959- 1973
1"/.'.'i:?G SAND RIDGES AND CHENIERS
• Z
FIGURE 11 Shoreline changes in south
and Cocoa Creek 1941-1973.
Cleveland Bay. between Sandf1y Creek
After McIntyre and Associates. 1974.
140
Nt
Coral Sea
Sand and liner udlment on S. W. coast
Sand on N. and S.E. coaata
Fringing coral f ••"
o I
L-...J
km
Cleveland
Bay
FIGURE 12 Coastal features of Magnetic Island.
141
\-7/6159 fT&!l saagrass and
[illillsadlment
•
donsa
saagrass
...... sand boach
Wosl Channol
'.<.
~o.
..
~ mangrov6S,
,
,
,
coral reel nat
MAGNETIC ISLAND
'-
'-- -
/
------
.......
- -/
I
I
\
\ flO\f\\
\ 'flo"'\
I
I
I
I
I
/
/ /,
(, /"'"".... /\./ ------ .....
J ,
30/5/74
Wosl Channol
'.<.
~o.
..
Bolger
Boy
\
,
MAGNETIC ISLANDYoung
Boy
/
I
I
I
\
\
\
I
I
I
I
I
/
/ ~
( ""'"" /" '- I \ _,/
'J -
FIGURE 13 Maps of south-west coast of Magnetic Island drawn from aerial
photographs taken in 1959,1974,1978,1981 and 1985. Note
especially the changing distribution pattern of seagrass.
142
28/11/78
•,
lmEI ..agru. and[IDj ..dlmenl
•
den..
..agre ..
....... und beach
\
/
--./
~ mangrov..
/
"
IS LAN DMAGNETIC
,
BolglM'
Boy
Young
Bo
-- .... _-----
/
,
I
\
\
I
I
I
I,
I
/ 1\ ..--._5m
"'/ _-' __ .... _,/ I .....1
.... .J W..I Channel
14/7/81
Cockle
Boy
•
- ...... -\,... .....
- I
S LAN DMAGNETIC I
/
;
---
----
Oolgtl'
" Boy'''-<,
-'- h'\
\
v"'''''B..,
".. ..... _-
W8Ili1 Channel
I
I
I
\
\
\
I
I
I
I
I
/
/
"
15/8/85
(
/
MAGNETIC ISLAND
Bolger
Boy
We.st Channel
Young
Bo
I
I
\
\
I
I
I
I
I
I
/ I'".. __/ r.s.........._ ...... _ ..... _t '?J./ __
" I
FIGURE 13 continued
143
- \ ....
\':lJ
~."'..
f\ '::.::.::'l....
t:(\"\ cn.,
...' I ) "~1
1. , £(;,,,. ~.•
~J{ I... _ ")<~"
."1,1'
FIGURE 14 Maps showing location of Beach Protection Authority cross profile
lines between Townsville Harbour and Shelly Beach and on Magnetic
Island.
144
FIGURE 14 continued
, - -------- ------------""~-~-----
..
M"'GH~lIC !.S'lANO
145
~"'"0">
CAPE PAu.Alle"IJA
•
R-ull N· S
,
0SEA~Nf Til.
FIGURE 15 Map showing location of Townsville Port Authority cross profile lines between Townville Harbour
and Cape Pallarenda.
2.B
2.6
2.4
2.2
2
loB
Vi-'r., III
-~ 1.6c:: w;... c
hJ ~
~ ~ 1.4c:: ,
...l 0
...l-C 1.2...
-'""',...-; '-"
~ 1
-">
-.l
0.8
0.6
0.1
0.2
0
-I
[
j i '
I I 1
11 I I ~ [~ f J I I[ I [ ~
fl ' : I Ii
I I I
I r 1, ~il II I I'
. : n i , .. I
I-Um1ftlrtt1mfrrmllljl [Jilll I11I nIlffW~~OOtl"mJI·lfljrt1lJI~lmu Ir I~~ I 1IIJIIUUi~~IIIIIIJIIJIIUlIIJLml~rilllllJ IIHUJlWll~
"' "II' liIII JIIIIIII IIIIIWI 11111I11111 1111I11 WIIHWU
Iilllil UlIIIIIIIIIIII::::lliJi IIWII: ::1 IIIIIIIJIIHIIIIIII :::w.Jl 1111 :::: ::::::ilH" 1IIIIIIIUlI'1IIIIIHlHmm~lmlll 1m IIIIJJIII~ I JJlW IiWI I11I 1::lllllllIllllIlilll W,1!1),l~W,11/111111 <lJII "" "III " III "Wi III" . '" .IWuw m III IUIII III '" " m"I~I Hili III I'
I "
lfl71J 1890 1910 19:10 19,,0 1970 1990
YEARS (Beginning Od,abel")
FIGURE 16 Townsville annual rainfall 1870-1987. shown for hydrological years beginning 1 October.
CLEVELAND BAY SEDIMENT SAMPLING
SITE LOCATIONS
• NE.... SITt!$
a
• 800 .....
S,TES
.9
16
•
.6
.7 .
26,
,16
•6
,15
.5
51
23,
,13
12
•
11
•
.21
20
•
19
•
'·5
.5
1'P4·0
o .'pI'
b
.'2
16
•
SEDIMENT SAMPLING
.'2
lB,
---Contour enclosing
values> 20%
17,
17,
,15
•
CLEVELAND BAY
% <0·063mm FRACTION IN SEDIMENTS
12,
S"''''Q~I..V Coc.
Ovr,rAL4 ,.-
£A!J;~i<&N
SIlPU~".s
Our~... u.
'-~CI
/'" .251
/ 32 I 16/. \ .
/
1.33 .23.......... .'7
'----.. "
, 12...... 24 '\ .'6
'\ . '\.. \.
\\\ '\ '\
'\1 17\ n l
J•\, • \ M/
//~~ \:iu/ .)1.
;' \ ................'- 11
/41 " M' M/ ., I
"../ .. / 3 \
..... 1611 • \0·2
t' 0 ~ 10 ~
. 0 1',
• '''lil
"
.2 ""3
""0" )(
'-\n4~' 911'- "'....... x
~,
.'~ 1·/'
....... .
~~..............
"
-'-
.'
2
3
..'
.W> .'
\ /" .• ',," ..~ ~~~. I' ,0 ,1
:~'~'" .'Ol~ ,. ,.
0"'1/ ./"\ .n ,'I .'
~..~: ~: ..<;"\~"'" J' .'L.'" ,." .- .. r'·,.. II 'Ito ;.>::::.... ., ',,: .
.. -" ':':;.s:::~
INDEX TO STATION LOCATIONS
FROM FIG 1.
."
FIGURE 17 Queensland Water Quality Council's Cleveland Bay .sediment pollution
study.
148
cSAMPLING
ABSENT
.-
10' - N° COlonies/gm.
sediment
+ PRESENT
.-
.-
- - - Contour enc.losing
area of +ve E.coli results
.-
.-
.IS6!
E. coli IN SEDIMENTS
.-
.-
CLEVELAND BAY SEDIMENT
.-
•
+
£",srll:lI&N
S"'f"".03
Ovr""u
/
.'
"' .... ,
I .+ I
I I\.+ I'
.- \ .+ I
\ \
\ .\ \ .-
" I \
',I \
-\ / .
'/ _ 1.:-
,,1,;. "', .1(70
- /' , ....... JI -.
'" / .of;' JI \ I
.,/..... 01' I .+ V
+ ",,'0' II 1\0-0 / o+~ 1{"
...., ~
.+ ""' -10'
'..: ,
-'l
'l;"a'" lit
, 1"\10+ ~,
• I ' ....' II
I "';'..
.s~;,~..... ,-c",:.•.•~.;'f;. ~~~:.:-
+ I • ................
01 .......
1
+
2·8
..'
INDEX TO STATION LOCATIONS
FROM FIG 1.
CLEVELAND BAY SEDIMENT SAMPLI'W-
COPROSTANOL mg/kg.
d
•
.U67
•
enclosing values> 0·1 mg/kg
{Detection Limitl
•
_._- .Contour
•
.'
.'
.'
."
.'
'·5F-0~
,.'
L·O
INDEX TO STATION LOCATlqNS
FROM FrG "
FIGURE 17 continued
149
..' CLEVELAND BAY SEDIMENT SAMPLING
,'" .1
e
47n
.uh
480
•
.500
1'1
480
480
•
TOTAL P mg/kg_
460
•
.500
•
1l;1.80
.460
.490
290
.400
.G20
.360
G30
•
.'.10/
.'
.'
."
.'
.'
.x
.'
."
."
90
.'pJ'
."
INDEX TO STATION LOCATIONS
fRm~ FIG ,.
CLEVELAND BAY SEDIMENT SAMPLING
.17
10
BICARBONATE EXTRACTABLE PHOSPHORUS
•
.'7
mg P I kg Sediment
.'3 .17 .15
14
.'5 .'9\ •
-
,
'\7 13 ,18 .16
"
,
,
1fIIlEX TO STATION LOCATIONS
fRO~1 FlG 1.
11
8
.'
/
O .. r .... tL
JS J7
17
•
,19
.20
16
•
16'
•
,17
18
•
.'9
.16
f
FIGURE 17 continued
150
CLEVELAND BAY SEDIMENT SAMPLING
ACID EXTRACTABLE PHOSPHORUS
- - - - Area enclosed by cont our
values:> 50mgP/kg sedim(!nt
9
,2
,6
,34
,41
2
•
31,
mgP / kg Sediment
2
•
,20
2
•
,34
,37/
..'
.' J
.. .. J
."
"
.'
53
.66
INDEX TO STATION LOCATIONS
fROM FIG '.
•
h
,4
,4
4,
2
•
,4
1
•
.2
,4
,
)(~56a
,
4
•
,4 .
CLEVELAIID BAY SEDIMENT SAMPLI NG
OIL AND GREASE tmg/kg I
6
,
,4
6
,6
,6
,2
,4
,11
S."'D"''-V c."C:.•._ .'J
Our~"'4t.
,3
E.. ,rLII.N
$"IIIII'iI"'"
P,"P4,U
/
.'
••¢'
10
13
..'
INDEX TO STATION LOCATIONS
FROM FIG '.
FIGURE 17 continued
151
CLEVELAND BAY SEDIMENT SAMPLING'
.-
INDEX TO STATION LOCATIONS
FROM FIG '.
•
A. Positive E .coli 1981 Survey
•. ~ 1982 •
c. Acid ex"ii-octable phosphorus ~50mg/kg
D Coproslon~1 > Q·lrng/kg.
Conlour enclosing ;;.3 +\o'C. parameters
2 •
•
• 0 /""1) •
/ .. / .'~' .0-
f )(1668
• ·0I
."
•
•
• •
•
• 'Co
.'
.'
,.
.'
,. ,
.- .' .'
2-8
••
.'
." >
,.
.'
.'
"
• ·0
."
\ / ."
"'-Y' ". <:
.-://'" ."»:.V.l' ."
.: \:. ." \.. }'
..... II
".' ".•,,. ":;,l' .n
•• '~ ';;:•.:" !!,..
....::=:........ •..... ~~~< ....
o
FIGURE 17 continued
152
40
~ 3.S
'"I! 3.0·
'iI
~ 2.S
"
2.0~ I.S
~ 1.0
.S
0 Jan reb Har Apr Hay June July Aug Sept Oct Nov Dec
1975
"
12
~ 10
,
~ • ~i •i •2
0 Jan eb Har Apr Hay , June ' July Aug Sept i Oct' Nov Dec
1975
June I July Aug
1976
HayApr
'.0
3.S
~
~ 3.0 Cyd()'lel&d
,
2.' ~~ 2.0-
~
i
"
12
~ 10
,
o-l-~J-an-~-eb~~Har~~Ap-r~~Hay-rjijn.·~'-J'u~l-y~~A-ug-~S"e-ptc-r'-OC=l---'~Ho-v-~oe-c-~
1976
FIGURE 18 Annual records of wave height (Hsig) and wave period (Tp) at
wave buoy near Cape Cleveland 1975-1987. After 8each
Protection Authority, 1988.
153
o Jan eb Har Apr Hay June Ju Iy Aug Sept I~ Nov I Dec
1977
14
12
t:l 10
III
,
~ .
i 6
~ .
2
o Jan Feb Mar r Apr ' Hay I June I July I Aug j Sept I Oct I Nov I Dec I
1977
.0
3.0 I. Reccning eQUlpmont mallunClion IG :2 5 rrapes unable 10 bo dCllllzoo uSing ....
I:~ "'-~T J~~t~
o Jan reb Har I Apr ' Hay , Jun. ' July , Aug , Sspl ' Dcl ' NOV' Dec '
1978
12
~ 10
,
~ .
8 •
~
\} .
~
2
o Jan reb Har Apr Hay Juns July Aug Sspl Dcl Hov c
1978
FIGURE 18 continued
154
'0Ie""...."'. e'~r ..",
~ ::ll
, 2.5 If
H
~ 2.0
!J! 1.5
~l 1.0
Apr I Nay I June i July I Aug I Sopt. IOCr.. I Nov I Dec.
1979
14
12
~ 10
.
2
o Jan I reb I Har I Apr I HaU I June' JuIU I Aug I Sept ' Oct I Nov I oec--r
1979
Cyclone S,mCl"t
I
14
12
fl 10
IJj
,
8~ ~~~ 8~ •
2
0 Jan eb Har Apr
FIGURE 18 continued
Hau June JuIU Aug I Sept' OCt ' HOv I nee
1980
155
14
12
~ 10 I
! ~ 1v~MJr ~I~~ ~l~
o Jan " eb ' Har---r-xpr • Hay , June ' Ju IY , Aug , Sept ' Oct I Nov·' Oec '
1981
'.0
14
12
l'l 10
IJj
I ~ ~~ ~~I 1~I~rJIV' f ~ \\~
o Jan' Feb I Har ' Apr ' Hay • June ' Ju IY , Aug ~Sept ' Oct • Nov ' Dec '
1982
FIGURE 18 continued
156
'0
3.5
on
m 30 Cycl;:nv Ell,," C)'Glc,oO Fllll
1 25 I f
I :i~\\;}\\~~ JJ~AM~~~~ V\
o Jan eb Har Apr Hay June 'JUlY' Aug , Sept ' Oct ' Nov ' Oec '
1983
..
12
!'~~)~r~ijff~ ~~Ulwrl~~~
2
o Jan ~Feb ' Har ' Apr ' Hay , June' July , Aug , Sept ' Oct . Nov ' Dec '
1983
4.0
3.5! 3.0 Cydono Inl1ld CycJCI"Ie lance~ 25 l J
!:i I~ \~~J~v~~ ftiliJN II
o Jan reb Har Apr--r-tlay , June ' July , Aug , Sept ' OCt ' Nov ' oec '
1984
14
12
! '~ ~ \~/~~ I ~h~11
2
o Jan reb Har Apr Hay June July Aug , Sept ' OCt ' Nav ' oec '
1984
FIGURE 18 continued
157
4.0 '
3.5
o· Jan eb ' Har ' Apr ' Hay , June ' July , Aug r Sept ' Oct ' Nov ' Dec
1985
"
o Jan reb Har Apr May June ' July , Aug , Sopt ' Oct ' Nov j Oec
1985
o Jan Har Apr Hi!Y'-:JUne"----;CJu"'ly--"--r::-r<':7~'
1986
,.
~ 10
,
~ e
i 0
i · ~
o Jan reb Mar Apr May , June ' July , Aug , Sept 'OCt Nov' Dec
1986
FIGURE 18 continued
158
"
12
g to
,
~ 8
i 8
!l •~ l'IlII.loIlU
a Jan Fcb Har~---'---Ha"U'-JlJne f Ju IY , Aug I Sept I Oct. I Nov i Dec i
1987
FIGURE 18 continued
159
30
25
~
.g 20
-o
~
~ 15~
a:
:>g 10
1ft
2.6 3.0
ALL DATA
30 29.6 30
2.'2.2
5
w
I::~3
O ......~.....+=M~~:.:w
0.2 0.1 1.0 1.4 1.'
HSIG(metres)
WINTER DATA
25
~
~ 20
.,
-o
~
3.02.21.0 1.4 1.'
HSIG(metres)
SUMMER DATA
0..0.2
5
25
i 20
~
FIGURE 19 Wave records from wave buoy near Cape Cleveland 1975-1987.
After Beach Protection Authority, 1988.
a) Histograms showing percentage (of time) occurrence of wa~e
heights (Hsig) for all wave periods (Tp)
160
50
46.6
.".:-:.:.:.:.:
40
~
QJ
E
-
'0 30§
:z:
~ 20
ag
?P. 10 10.1
2 4 6 6 10 12
WAVE PERIOD Tp (Secs)
ALL DATA
14 16
50 49.9 50
2
40
43.4
~
QJ
E
-
-
.9 30
~
:z:
w
a: 20
a
u
~ ': L...illi:~s;iii5~1:::iJ::~II;:;;I;;;I;;;;II:;;I2:II:;;;li2:IIL::;;':;::~:j:;:::;;;':;:J.b.1;Oql.36.\01;l.2.....-.._--.
4 6 6 10 12 14 16
WAVE PERIOD Tp (Secs)
WINTER DATA
16
...............
Ijl[III,llllllllilll;[]) n, "
o .L.L::;ill4142L4:2h=?~~--r-----,
2 4 6 6 10 12 14
WAVE PERIOD Tp (Secs)
SUMMER DATA
40
FIGURE 19
b)
continued
Histograms showing percentage (of time) occurrence of wave
periods (Tp) for all wave heights (Hsig).
161
""'"
~
0">
N
-
L~1(~;~~i'
c"'~ 'fi' ,,, y'>' ! >' , : ('<"
a_ , o."..l_"---O' "'C I 80---: _" ~C' ;":5
FIGURE 20 Cleveland Bay wave refraction diagrams. After McIntyre and Associates. 1974.
Ca) For south-east waves with 5 second period.
~
a.
w
-
,
...
...........J: ---.,-....:.- -;- .~~~""'H" " ,
. '..., , .. - "" .- ..•• '!~. . .. '.~.. , "". .'. I , ; ~ ••. , "c' •...~..~.. . . "< p' '<
.! ~. . .. <, II fCc .,.
--- ; '<=,.. - \ T.80· ...
FIGURE 20 continued
(b) Wave refraction diagram for easterly waves with 5 second period.
"~---+--'.>-'~";+':. ,
..--::
'-l-ol- •. \ :1
,..t~}]:S2l\~)n···
':9' ~ .~ q ~oo E.:;-: ':"1' ";;"''g:
""'-.:. i: "=' "'c" .' Lr "1.!! \: \-.~. 1 j 80 .._. ~..... \ )'~I..§'o \ .
, ."u.,. ,,_ .. 4 "'l
,
-
0'>
~
FIGURE 20 continued
(c) Wave refraction diagram for north-east waves with 5 second period.
.. \, -
,
\
,
\
: ,
!
,~
•
I'
• to" '.",.
.! ..
/~
/~.. :~.....
· . _C.p. C1.~~
/ '.....-, '· ', -... \
/
., .\
. '
. - '
- .- I
• R~l1 Rod;
. led·... ,.,:,1, .;,. ..
..l
-rN=-c!
I . i ilk:~;
i ; I
10
yA
~.ei?'&.:-'-'~
"""- 'fJ. :~,~.:~.~>(
, ;-l .........
IOWNSVILL..
.......... ,., ..,. i.c ... · . . I 85 .
I .
,..! ,... .
-'I . c. !
~'\ Cope PoIlor.ndo,- .: ::::.:!l-::J--__ l:' , ..~~ :~ ~'i~1 ,
'"
~?!
'"x-c
~ ~
o •
-~~
~
'"
'"
FIGURE 21 Drogue measurements by Townsville Port Authority
(a) Flood tidal currents.
_.~.-.-:
--j- --
- I
__1
:
J
166
LO
o
Vl
+'
C
<ll
<-
<-
"U
<0
-0
'~
-0 +'
<ll
"
.0
C .0
-~ W
+'
C ~
0 .0
U ~
~
N
W
e>:
:::>
(.!J
~
'"-
~6 11.7 0 1470 30"'-
AYR.
---~~"
\\\ ~
\\
AND
t . ..a r Ie 115 ~O
Scale (km)
147°
'\, DRIFTER RELEASE POINT
\, MOVEMENT PATH
19 °]0# ! ( L.. '--. II ~ 190]I ) '- ? I '\. I
"'.
-.J
FIGURE 22 Release and retrieval points for Woodhead sea-bed drifters and schematic transport paths.
Drifters released in November 1976 and March and April 1977 during moderate and rough sea
conditions. After Belperio. 1978.
cd
5__
l ..'--i--t--H
Se,,'. "",1
______ ---2 (
-- '5_
-'20'0",- ~-------
-50· ~'--~-=;<:=;:;~ 2-- __
b
FIGURE 23 Distribution of surface suspended sediment in Cleveland Bay.
Contours in parts per million total particulate matter.
After Belperio. 197B.
a) For sea conditions smooth and smooth-slight.
b) For sea conditions slight and slight-moderate.
c) For sea conditions moderate and moderate-rough.
d) For rough sea conditions.
168
" ....
". '.\
.',
~ ... '
."
a
b
FIGURE 24 a) Isopachs of dredge spoil distribution within Cleveland Bay as
inferred from vibracores.
b) Surficial sediment facies distribution within Cleveland Bay beneath
dredge spoil. 1a - terrigenous bay mud; 1b - bay mud seagrass
subfacies; 2a - silty fine sand foreshore facies; 2b - tidal flat
sands; 3a - island-connected terriginous mud; 3b - is1and-
connected facies containing carbonate component; 4-fie1d of
longitudinal sand bedforms; 5-P1eistocene at shelf surface. often
with surficial armour of cohesive shelly mud.
After Carter and Johnson. 1987.
169
HAP l.EGEND
Seagr:il5S Covet"
< 10\ cover-
between 10' and 50\ cover
> 50\ cov~r
Dugong ~lqhtln9s
DugOllg (ceding trials sighted
Tur:tlc slghtinq
SEAGRASS SPECIES CODES
-II
II
®
CS 1
EA 2
HS 3
HO 4
HU\·J 5
CR 6
HUT 7
SI 8
TH 9
HD 10
HP 11
HT 12
~JS 13
ZC 14
FIGURE 25
Cymodocea serru1ata
Enha1us acoroides
Ha1ophi1a spinu10sa
Ha1ophi1a ova1is
Ha1odu1e uninervis (wide)
Cymodocea rotundata
Ha1odu1e uninervis (thin)
Syringodium isoetifo1ium
Tha1assia hemprechii
Ha1ophi1a decipiens
Ha1ophi1a pinifo1ia
Ha10phila ovata
Ha1ophi1a tricostata
Zostera capricorni
Seagrass distribution in the Cleveland Bay area.
Draft maps (1988) from Northern Fisheries Research
Centre, Queensland Department of Primary Industries.
170
oIslandMegnetlc
Horseshoe
+
HS,
HS
HO
Channel
o
West
+
o
~";.
'lI( ..) 0
Middle RI o
o
CLEVELAND
BAY
cs.~
....
r--,
/ "-
/ ' "-
,; '.....
I \
\
11$ 00
-=- HP
"'
o
TOWNSVILLE
7L---,----,---,--,-----,5 tE.
kilometers r;J-
FIGURE 25 continued
171
'\r~.. ,
HD /,.1 ..l"'~\,,~ ~~
. ,J. t.' .~~
""HS'. .....-4......-, . ~~ ....w ... HUW
. '. "HUW'" HS
HO
WS
19' IS'S
o becton,
kilometers
I
147 E
cape Cleveland
o 5
, ! ! ' , ,
,
.......:.: ..:: ..
CS .
f:~·W!!!j!:~j;Jj·
/
/
I
{
I
I
/
/
I
I
I
I
-',,"" ,"
" .-
. II
;':> - ,.::1
,,----"' ,: 1
"" - '\.... \ I
.... ~, \ I
....... II\\
I
I
I
r1N ---
'li
BAY
....
CLEVELAND
o
\
\ .,..HS
" '::m~::
" .;'';
,
"-
"- ,
-.
----
o
CS
rv1Clgnetic
Island
~~,,!"). 0
-0'
o
':: :"\ HJ
',.:;:.
~HO..;-~
'"'V'.': C<;;..,
~
-..J
N
FIGURE 25 continued
..
::Ii
:' ../",)
~llr(
,"
o
o
""0:
,..
'"III
(/)
'u)
''2!
"'0
Q!
"c
'~
+'
C
o
U
~
•
..
E
o
'i
o
'"
'"o
.c
(J)
'"E
"
/
,. (
: I
">~
'/ ""-'/
t
f"
'"c:
'"
"~
~
'"0:
w
o
0)
-CO
"
173
PLATES
174
1 Bucket Dredge 'Octopus' dredging Ross Creek in 1901.
2 Suction Dredge 'Morwong' in October 1946.
175
3 Suction Dredge 'Townsville' maintaining depths in the Swing Basin.
I, I
(,I"
i {I
4 Bucket Dredge 'Cleveland Bay' in 1964 on her final assignment.
dredging the new oil and tanker berth.
,176
5 Trailer Suction Dredge 'Sir Thomas Hiley' carrying out developmental
dredging in the Swing Basin in 1973.
6 Trailer Suction Dredge 'Sir Thomas Hiley' carrying out maintenance
dredging in the Swing Basin in June 1988.
177