UNSW Coastal Management

IMPROVING THE HEALTH OF THE

COOKS RIVER

Michael Greenwood mrgreenwood@hotmail.com

0437 854 370

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COOKS RIVER

The Cooks River catchment drains 10 000 hectares of land in the southern and

inner western suburbs of Sydney. It begins in Graf park in Bankstown and flows

east for 23 km before entering Botany Bay just south of Sydney airport. The riv-

er runs through 13 Local council areas in some the most heavily urbanised and

industrial areas in Australia.

Almost 400 000 people live in the catchment and many Industrial sites occupy

the banks of the Cooks and its tributaries. Stormwater is a major contributor to

the quality and quantity of water that ends up in the river. For many years in-

dustrial factories along the Cooks deposited their waste straight into the river

but these practices have since been outlawed. Efforts to control and improve

the health of the river are ongoing. Raising awareness of the issues and pro-

moting community involvement is an important step to reducing our impact on

the Cooks river.

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CLANS OF THE GOOLAY’YARI

The Aboriginal people who lived along the

Cooks River included the Cadigal people to the

north, the Wangal on the western lands and

the Bidjigal (Bediagal) people to the south. Col-

lectively they are the Eora people or ‘coastal

people’. The bountiful resources of the River

were an ideal source of food for the clans and

sandstone outcrops provided shelter. Shellfish

and plants were collected, birds and fish hunt-

ed and canoes were built to gain access to the

whole river system. Middens or shell fish piles

provide an understanding of the behaviour of

the clans and also what species were living in

the river at the time. Rock shelters contain

shell, bone, flaked stone and charcoal deposits

which can reveal further knowledge of how

these people lived and how they relied on the

river.

During construction of the Alexandra Canal by Europeans in the 1880’s, a dugong skeleton

was found which showed butcher marks on its bones. These marks were made by the Ca-

digal clan using blunt-edged chopping tool which was also found near by. The presence of

the dugong in the River infers that sea grass beds which are food for the dugong also exist-

ed. Archaeological evidence points to a peaceful and resource rich existence along the river

by the Eora people. Tragically, introduced small pox devastated the Eora populations and

confrontation between Europeans further fragmented communities. Access to their river

became increasingly difficult as settlers cleared land for grazing and industry that was to

lead the environmental problems that faces the river today.

Three pronged spears were used by the Eora people in Eucalypt bark canoes to hunt fish throughout the Goolay’yari. (Image: www.marrackville.nsw.gov.aul)

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Captain Cook was thought to be describing the Cooks River and although it showed a great

deal of promise for the new colony in terms of good agricultural sites and a source of fresh

water, the later settlers noted the extensive swamp areas and decided on Parramatta as a

more promising agricultural

site for the colony. The land

adjacent to the river was

mainly used for grazing and

the plentiful supply of

Casuarina trees proved ideal

for roofing shingles. Shells

left by Aboriginal people

(middens) were crushed and

the Lime they contained was

used to bind mortar.

THE ARRIVAL OF THE EUROPEANS

“I found a very fine stream of fresh water on the north side in

the first sandy cove within the island before which a ship

might lay land-locked and wood for fuel may be got

everywhere” Captain James Cook, 1770.

View of Tempe on Cook’s River, 1845.

(Picture: Conrad Martens, Library of NSW.)

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MAKING A COLONY

The Casuarina tree or Swamp Oak made excellent roof shingles. (www.flickrhivemind.net )

1800’s

Lime was in such critically

short supply in the early years

that the industry thrived with

many colonists making a living

collecting shells along the

banks of the Cooks River.

The growing colony put in-

creasing pressure on food sup-

plies and steadily prices in-

creased. Many settlers along

the river sold or leased their

properties to others willing to

try their luck at farming. 1830’s

The beginning of the 1830’s saw an expansion

along the river with roads and bridges accommo-

dating a wave of Government sponsored mi-

grants keen to make a new life for themselves in

the burgeoning colony. A Dam was built at Tem-

pe with the hope of establishing a constant wa-

ter supply for Sydney however the water above

the dam remained salty and tidal flushing was

restricted which would ultimately lead to future

ecological problems for the

river.

Tempe House, and dam, Cooks River 1836. (Samuel Elyard).

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INDUSTRY MOVES TO COOKS RIVER

The Public health Act of 1848 banned noxious trades from Sydney so the Cooks river pro-

vided the water needed for Industry. Industry moved there in droves. Wool washes, tan-

neries and boiling down works appeared along the banks and so did the industrial waste

which simply flowed straight into the River.

1880’s The 1880’s saw a land boom along the River and land was cleared in earnest. This in-

creased Stormwater runoff leading to soil erosion and a build up silt in the river. Reed

beds spread into the river, recolonising the silt deposits which caused a blockage and then

came the inevitable; the flood of 1889.

Flood On a weekend in May, 1889, 430 mm (17 inches) of rain fell in Sydney.

Settlements along the River were decimated. Dams and bridges were

damaged, many families evacuated but

the Chinese market gardeners were

most severely hit. Gardens were washed

away and the farmers houses were

flattened. By 1891, only 1 Chinese

household remained. The flood acted

like a catalyst to growing concerns over

pollution and human health issues;

something had happen to fix the grow-

ing problems concerning the river.

Dam and Tannery, Cooks River, Canterbury 1901. (www.thenoones.id.au)

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CONCRETING THE RIVER BANKS

Growing Concerns The River was fast becoming an environmental nightmare. An outbreak of typhoid fe-

ver in 1896 was attributed to sewage overflow into the river at Wolli creek. Among the

suggested solutions proposed by engineer

H B Henson was the construction of a series

of canals to join faster flowing rivers such as

the Parramatta to the Cooks in an effort to

speed up the flow and help to flush the de-

bris, silt and pollution out to sea.

1920’s & 1930’s

By the 1920’s no substantial remediation

efforts had been implemented. A group

of unimpressed citizens formed the

Cooks River Improvement League and

set about raising public awareness and

demanded Government take a more committed role in remediation responsibilities.

The Great Depression hit in the 1930’s but nevertheless money was found partly

through the Unemployed Relief Council to begin dredging works and the concreting

of the river banks.

Storm Water channel, Burwood, 1938.

(State Library, NSW)

Cooks River Improvement. Lindsay St, Campsie, 1938

(State Library, NSW)

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COOKS RIVER IMPROVEMENT PLAN

1940’s The Cooks River Improvement

Act of 1946 resulted in the

concreting of banks of many

parts of the River and its trib-

utaries and the installation of

sheet steel piling in an effort

to reduce the risk of flooding.

The mouth of the Cooks River

was relocated 1.6 km inland

to accommodate the expansion of the air-

port which all but destroyed the River’s re-

maining wetlands. The Rivers and Fore-

shores Improvement Act of 1948 was

passed into legislation. The Act set objec-

tives including the removal of obstructions

and the improvement of rivers and the

prevention of erosion of lands by tidal and

non-tidal waters.

"the Cooks River system is heavily polluted, with large portions

of it incapable of sustaining aquatic life. It is not suitable for

bathing and needs a massive clean-up campaign to restore it to a

tolerable level, not to mention a respectable level” A.B. Distefano, 1946.

Lower Cooks River. Notice the steel sheet piling for flood reduction (Photo: www.ourriver .com)

Cooks River (at right) meets Cox Creek, South Strathfield.

(Photo: Alan Waddell)

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RIVERS REBORN

1950’s & 1960’s

Increasing pollution issues continued in the 1950’s and 1960’s. Local coun-

cils expressed concerns as to the safety of fishing in the river. Oil from the

Enfield Railway yard and acid from a Battery factory were reportedly dis-

charged into the river. 1970’s & 1980’s

The ‘Clean Waters Act’ is passed in the

NSW parliament with the State pollution

control commission implementing the ob-

jects of the Act. However, ‘fish kills’ were

recorded every few years from raw sew-

age, cyanide and illegal dumping of chro-

mium-ammonium into the river. The Nat-

ural Gas Company accidentally spilt

20 000 litres of organic pollutants and

were fined $25 000 or just $1.25 per litre!

Little wonder it happened a lot.

1990’s to Present

In the early 1990’s the State Government intro-

duced the Environment Offences Act which in-

creased fines to $1 000 000 for polluters . The

Cooks River Catchment Management Committee

was formed which had representatives from local

councils, state government agencies and community groups. Environmental awareness

started to grow and installations to trap rubbish and pollution entering the river were

built. Rivers Reborn projects were undertaken by groups such as the Cooks River Valley

Association. The work is ongoing and the River is far from healthy.

Pollution on the Cooks River

(Image; www.moblog.com)

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POLLUTION ISSUES

So What Exactly Are the Pollution Issues in the Cooks River?

The Cooks River is one of the most polluted in the country despite recent efforts to im-

prove the quality for the wildlife and people alike. Illegal dumping and industrial wastes

are major problems in the Cooks catchment. The main problems are;

Suspended Solids — soil particles, leaf litter and sediments from erosion and

enter drains which flows directly into the river when it rains and smother aquatic

plants, destroying habitat for aquatic animals.

Gross Pollutants — plastic bottles, plastic bags, cigarette butts and grass clip-

pings are all types of gross pollutants. They affect the quality and reduce oxygen lev-

els of water.

Sewage Overflows — there are over 150 that sewer overflow points along the

river that discharge into the river after heavy rain. High levels of faecal contami-

nants make the river unfit for fishing, swimming and in some areas even boating can

be dangerous.

Heavy Metals — lead, zinc, mercury, chromium, silver and copper are found in

the river accumulate in the river bed and affect the bottom dwelling organisms and

the animals that eat them.

Excessive Nutrients — nutrients from natural and non-natural sources like ani-

mal faeces and fertilisers can get into the drains and enter river causing algal blooms

that are harmful to aquatic life.

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WATER SENSITIVE URBAN DESIGN

Hard Surfaces

Hard surfaces are a fact of life in a city. Paved surfaces including roads, carparks, footpaths

and roofs make up a large proportion of the surfaces found in the Cooks River catchment.

Up to 90% of the pollutants found in stormwater that flows

into the river passes over these hard surfaces. Although

drains are meant for rain many pollutants and rubbish end

up in them and go on to affect water quality in the river.

What is Water Sensitive Urban Design? (WSUD)

Water Sensitive Urban Design is an approach whereby a natural water

flow cycle is mimicked as much as possible in an urban setting. In a natu-

ral setting, rain either soaks into the soil (infiltration) is evaporated or

transpired by vegetation. Increasing hard surfaces prevents water from

soaking into the ground thereby increasing the risks of flooding and in-

creasing pollutants entering the river. By incorporating a range of meth-

ods WSUD aims to improve quality and reduce the quantity of water en-

tering waterways. Restoring a natural flow of water can help improve the

health of the river.

http://www.crva.org.au

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WATER SENSITIVE URBAN DESIGN

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APPLYING WSUD TO THE COOKS

Selecting the right Treatment

Selecting the right treatment or combinations of treatments is an important

consideration when adopting WSUD strategies. A lot depends on the specific ar-

ea, is it a parkland or roadway?

The soil type and lye of the land are also important, and the type of pollutant

you want to target. A good design and adoption strategy can increase the chanc-

es of success. All these methods below are being used along the Cooks River to

reduce pollutants entering the river.

Gross Pollutant Traps (GPT’s)

These traps act like sieves that collect litter, leaves and

coarse sediments as they pass through. They can be emp-

tied and the rubbish taken to landfill rather then ending

up in the river.

(Image: NSW Office Environment & Heritage)

Grassed Swales

Grassed or vegetated Swales are open channels that help

to remove sediments and suspended solids from entering

waterways. The water flow is slowed to promote infiltra-

tion into the soil. Swales are suitable for use along road-

ways. (Image: www.wsud.org)

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APPLYING WSUD

Rain Gardens/Bioretention Systems

Rain gardens are landscape features that are used to treat

stormwater on site. They collect rain water, and remove sedi-

ments, nutrients and also slow runoff by passing water

through sand or gravel. Water can be collected underground

in perforated drains. (Image: www.wsud.org)

Ponds, Wetlands and Saltmarshes

Wetlands are excellent systems at removing soil, sediments,

nutrients, chemicals and rubbish from stormwater. They pro-

vide a habitat for a variety of aquatic life such as birds, turtles

and frogs. Ponds are bodies of water that settle sediments and

soil out of water. (Image: www.wsud.org)

Permeable Paving

Holes in the pavers allow water to flow through either into the

ground or into storage tanks. Runoff is reduced which can help

with erosion. Porous concrete and asphalt can be used in

some situations.

(Image: www.wsud.org)

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WSUD AT THE COOKS RIVER

Cup and Saucer Creek Wetlands

Cup and Saucer creek is located in Canterbury on the southern side of the Cooks River.

The constructed Wetlands were

opened in September 2010. How do the Wetlands work?

1. A Gross Pollutant trap collects rubbish as storm-

water enters the creek from the sur-

rounding suburbs.

2. The water is then diverted by a weir

and is taken into the first of three ponds

where plants filter out nutrients and oth-

er pollutants.

3. The water then flows into two small-

er ponds and allowed to settle. The water

infiltrates into the ground and enters the

Cooks River. If the ponds fill up an over-

flow sys tem directs the water into the

river.

4. Permeable pavers were also in-

stalled along the banks to reduce runoff.

Native Plantings

In addition to the use of WSUD, the

Canterbury Council has planted

30 000 shrubs and grasses, 10 000 water plants and 30 large trees such as Turpentine and

Eucalypts. Plantings help to reduce erosion, assist with rate at which water infiltrates into

the ground and provide habitat for wildlife not to mention creating a parkland for the

community. Re-establishing the endangered ecological community the Cooks River Castle-

reagh Ironbark Forest is a goal of many local councils of the catchment.

Stormwater from Cup and Saucer creek is diverted into the wetlands for treatment and back into the Cooks River.

(Image: savingourtrees.com)

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WOLLI CREEK

Wolli Creek and Saltmarsh Establishment

Wolli creek lies south of Cup and Saucer creek and flows

north into Cooks River at Tempe. Coastal saltmarsh is an en-

dangered ecological community and provides habitat for

birds, and many aquatic animals. They are also

important in the lifecycle of many fish includ-

ing commercial species.

WSUD at Wolli Creek Catchment

The Turrella Creek Saltmarsh has Gross Pol-

lutant Traps installed and constructed

swales that divert water away from the salt-

marsh. There are also ponds to control the

water entering the wetlands. Indigenous

plants help stabilise the banks and park-

lands create recreational areas for the com-

munity. There are also three Bioretention

systems in operation in the Wooli catch-

ment.

At the Henderson Street footbridge there is

installed a fish ladder to assist with the mi-

gration of fish up steam to spawn. Fish navi-

gate a series of ponds at high tide to get to

the less salty freshwater at the head of

Wolli Creek.

Bioretention Swale construction along Highcliff Rd, Earlwood. (Image: www.cooksriver.info)

Installing a huge Gross Pollutant Trap at Steel Park, Marrickville. (Image: www.cooksriver.info)

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Transformation of the Cooks River providing habitat wildlife (Images: www.sydneywater.com.au)

Bioremediation basin at the end of Johnston St, Earlwood October 2011. (Photo: Michael Greenwood)

Constructed Wetlands at Turella Park (Photo: Michael Greenwood)

Johnston Street Bioretention Pond construction

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Coolabah Reserve. Stormwater enters the GPT (left) and then flows into Wetland where it is treated (below). It then flows into Bardwell Creek and eventually into the Cooks River. (Photos Michael Green-wood)

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The fish ladder at Turella Park, Wolli Creek.

Johnston St Bioremediation Basin. Water will flow into the GPT from the road and then into the Bioretention basin where sediments and nutrients are filtered. Treated storm water then flows into Wolli Creek. (Photos Michael Greenwood)

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What can I do to help the Cooks River?

There are many little things that make a difference, some obvious and others not so

obvious. Being conscious about what you do can go along way to improving the health of

the Cooks River. Here are some ways you can make a difference….

Be aware of the drains and where they end up! Realise that most

things that go into the drain end up in the river.

Rubbish, grass clippings, paint, chemicals….

Become a knowledgeable member of your community and teach

family and friends about the benefits of Water Sensitive Urban

Design.

Wetlands, Gross Pollutant Trap’s, Bioretention ponds….

Think about water use and ways of reducing use;

Install a rainwater tank, plant natives,

build a mini raingarden in

your backyard!

GETTING INVOLVED

Reduce runoff by installing a Raingarden! (www.ourriver.com.au)

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GETTING INVOLVED

Get involved in the many local community groups that participate and

care for the Cooks River.

Wolli Creek Preservation Society

www.wollicreek.org.au

MUDCRABS— Cooks River Eco-Volunteers

www.munropete@ozemail.com.au

Mizaan Ecology and Awareness Group, from the Al-

Ghazzali Centre for Islamic Sciences & Human Development

mizaancoordinator@alghazzali.org

Greenway www.greenway.org.au Cooks River Valley Association www.crva.org.au Marrickville Landcare Group

www.marrickville.nsw.gov.au

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FURTHER INFORMATION AND ACKNOWLEDGMENTS

Sydney Water www.sydneywater.com.au Sydney Metropolitan Catchment Management Authority http://www.sydney.cma.nsw.gov.au/cooks-rive Canterbury Council www.canterbury.nsw.gov.au Cooks River Valley Association www.crva.org.au Marrickville Council www.marrickville.nsw.gov.au Office of Environment and Heritage www.environment.nsw.gov.au Department of Environment Climate Change and Water Our River-Cooks River Sustainability Initiative www.ourriver.com.au Saving our Trees www.savingourtrees.com Bankstown Council www.bankstown.nsw.gov.au Water Sensitive Urban Design www.wsud.com Strathfield Council www.strathfield.nsw.gov.au

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