The Sydney Catchment Authority (SCA)manages a total of 21 storage dams, holdingover 2.5 million megalitres of water. Water forthese storages is collected from five catchmentareas, occupying 16,000 square kilometres.

The Warragamba Catchment suppliesWarragamba Dam, Sydney’s most importantsource of water. Completed in 1960,Warragamba Dam holds about four times more water than Sydney Harbour and accountsfor about 80 per cent of the region’s availablewater supply.

<WARRAGAMBA DAM

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DAMS OF GREATER SYDNEY AND SURROUNDS

Warragamba

The Sydney Catchment Authority (SCA)manages a total of 21 storage dams, holdingover 2.5 million megalitres of water. Water forthese storages is collected from five catchmentareas, occupying 16,000 square kilometres.

The Warragamba Catchment suppliesWarragamba Dam, Sydney’s most importantsource of water. Completed in 1960,Warragamba Dam holds about four times more water than Sydney Harbour and accountsfor about 80 per cent of the region’s availablewater supply.

<WARRAGAMBA DAM

WA

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DAMS OF GREATER SYDNEY AND SURROUNDS

Warragamba

Formation of the SCAThe SCA was established in 1999. Its task is to protect Sydney’s catchments and to supplybulk raw water to its customers, which includeSydney Water and a number of local councilsand other bodies.These customers then filter the raw water and distribute it to households, businesses,and other users. Nearly four million people, or about 60 per cent of NSW’s population,consume water supplied by the SCA.

Greater Sydney’s drinking water catchments

A catchment is an area where water iscollected by the natural landscape. In acatchment, all rain and run–off watereventually flows to a creek, river, lake or ocean, or into the groundwater system.

Natural and human systems, such as rivers,bushland, farms, industry, homes, plants,animals and people can exist alongside oneanother in a catchment.

The Sydney Catchment Authority (SCA) protects five catchment areas, which providewater to greater Sydney and local communities.They are: • Warragamba Catchment • Upper Nepean Catchment • Woronora Catchment • Shoalhaven Catchment • Blue Mountains Catchment

The catchments occupy about 16,000 squarekilometres in total. They extend from north of Lithgow and Blackheath in the upper Blue Mountains, south to the source of theShoalhaven River near Cooma, and fromWoronora in the east to the source of theWollondilly River near Crookwell.

The catchments

WARRAGAMBA CATCHMENT>

Located about 65 kilometres west of Sydney in a narrow gorge on the Warragamba River,Warragamba Dam is one of the largestdomestic water supply dams in the world.

Water is collected from the catchments of theWollondilly and Coxs River systems, covering anarea of 9,050 square kilometres, to form LakeBurragorang behind Warragamba Dam.

Lake Burragorang is the largest urban watersupply in Australia, containing about four timesthe volume of Sydney Harbour. It is the mainwater supply for nearly four million people inthe Sydney region.

Warragamba Catchment

Australia is one of the driest inhabitedcontinents on earth. Water has been vital to thesurvival and prosperity of Sydney since the firstdays of the new colony. The need to ensure areliable water supply through times of droughtand erratic seasonal rainfall has driven thedevelopment of several complex and innovativewater supply schemes.

Sydney’s first water supply came from the Tank Stream, named for the ‘tanks’ orreservoirs cut into its sides to save water. The stream, which wound its way through thecolony before emptying into Sydney Harbour atCircular Quay, degenerated into an open sewerand was abandoned in 1826.

Convict labour then developed Busby’s Bore, a four kilometre tunnel leading from theLachlan Swamps, (now Centennial Park) andending in the south–east corner of Hyde Park.

By 1852, drought and increasing population led to the call for a more permanent water supplyfor Sydney. A third water source, the BotanySwamps Scheme, began operations in late1859 but within 20 years this once copioussupply of fresh water was depleted.

The Upper Nepean Scheme was Sydney’sfourth source of water supply. Completed in1888, the Scheme diverted water from a seriesof weirs on the Cataract, Cordeaux, Avon andNepean rivers to Prospect Reservoir via 64kilometres of tunnels, canals and aqueducts,known collectively as the Upper Canal. Thebuilding of Cataract, Cordeaux, Avon andNepean dams between 1907 and 1935 greatlyimproved the Scheme’s capacity.

Sydney’s evolving water supply system

< BUSBY’S BORE OUTLET, HYDE PARK.PAINTING BY J.SKINNER

TUNNEL INTERIOR,UNDER OXFORD STREET

>> VICTORIA BARRACKS:SHAFT DOWN TOBUSBY’S BORE

Warragamba River was a short stretch ofwater, only about 23 kilometres long, that ranfrom the junction of the Coxs and Wollondillyrivers to its junction with the Nepean River.

The Warragamba River offered two importantadvantages as a site for a major dam. Firstly ithad a large catchment area and secondly the river flowed through a long narrow gorge. A comparatively tall and narrow damcapable of impounding a vast amount of water could be built.

Its potential was identified as early as 1845. The first sketch plans were drawn up in 1867, but plans were deferred during theconstruction of the Upper Nepean damsbetween 1907 and 1935. An increasing demandfor water from an expanding population, and a record drought from 1934 to 1942, forced thedevelopment of Warragamba Dam to ensure a reliable water supply.

In the interim, the Warragamba EmergencyScheme was built to urgently address Sydney’scritical water shortage. This scheme consistedof a weir and pumping station on theWarragamba River and a pipeline to ProspectReservoir. It began operating in 1940 and was inuse for almost 19 years until the completion ofWarragamba Dam.

Why Warragamba Dam was built

WOLLONDILLY RIVER IN BURRAGORANGVALLEY BEFORE FLOODING

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Warragamba Dam was a major engineeringfeat of the mid 20th Century.

Following extensive geological examination, twotemporary dams and a tunnel to divert the riverwere built first. More than 2,300,000 tonnes ofsandstone were removed from the site.

Concrete was mixed on site using 305,000tonnes of cement and 2,500,000 tonnes of sand and gravel. The sand and gravel weretransported from McCann’s Island in theNepean River via a unique aerial ropeway.

The dam was built in a series of largeinterlocking concrete blocks. A system ofoverhead cableways lifting 18 tonne bucketswas used to place the concrete.

Ice was mixed with the concrete to control heat generation and to prevent cracks fromforming. One of the first pre–stressed concretetowers in Australia was built to house theice–making plant.

Residents living in the Burragorang Valley,which was to be covered by rising waters, wererelocated. More than 64 square kilometres oftrees were cleared so that they would not rotand float downstream, to block the dam’soutlets and crest gates.

Pedestrian access between the Warragambatownship and the work area was provided bytwo suspension bridges, one across Folly Creek and the other across the Warragamba Gorgejust downstream of the dam.

When the then Premier of NSW, the Hon.Robert J. Heffron MP, officially openedWarragamba Dam on 14 October 1960,thousands of guests, workers and their families gathered for a day of celebration.

How Warragamba Dam was built

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CELEBRATING THE TWO MILLIONTH TONNE OF CONCRETE POURED

WARRAGAMBA WALL UNDER CONSTRUCTION

INTERLOCKING CONCRETE BLOCKS

LIFE IN THE WARRAGAMBA TOWNSHIP

Warragamba was established specifically as a construction town. At its peak the townhoused about 3,500 people, in mostlyprefabricated cottages, as well as barracksfor single men and women. Some 1800 menfrom at least 25 nationalities, many of whomwere post WWII immigrants, workedalongside each other with little friction.

Work, family and social activities all centeredaround building the dam. The Water Boardprovided roads, utilities and other services butmany of the town amenities could not haveexisted without the voluntary labour andfundraising activities of the residents.

Unlike other communities that disappearedalmost overnight once dam constructionended, Warragamba has remained aclose–knit township which even today proudly highlights its relationship with itsawe–inspiring neighbour

FESTIVAL OF CAROLS, 1964.>>

CONSTRUCTION HISTORY

Geological Investigations 1942River diversion works 1946Site works 1948Excavation 1950Concrete pour 1953Completed and opened 1960Wall raised five metres 1989Auxiliary spillway started 1999Auxiliary spillway completed 2002

< WARRAGAMBA PRE–SCHOOL, 1955

Warragamba Dam supplies bulk water to threewater filtration plants where it is filtered anddistributed to people living in Sydney and thelower Blue Mountains.

The best quality water is selected and drawnthrough screens at three outlets in theupstream face of the dam. After flowing bygravity to the valve house, two pipelines feedthe raw water to Prospect water filtration plantand via off–takes to smaller filtration plants at Warragamba and Orchard Hills.The filteredwater is then distributed to households,businesses and other users.

The five crest gates, central spillway, dissipatortraining walls and apron (stilling pond) allmanage the discharge of normal floodwatersand are critical to dam safety. The auxiliary sidespillway will operate only in rare and extremefloods, and will divert excess floodwatersaround the dam.

Eraring Energy owns and operates the50–megawatt hydro–electric power station at Warragamba which generates green power only when there is a high level of water in the lake.

HOW THE DAM IS MONITORED

SCA officers inspect and monitor WarragambaDam through a network of more than fivekilometres of galleries. They monitor waterpressure, seepage, and any physical changes inthe dam structure and its foundations toensure these are within acceptable limits.

Warragamba Dam was designed to deflectslightly as the lake level rises and falls. These deflections are measured regularly using precise surveying techniques. Sensitiveseismic equipment located in the dam andsurrounding catchment monitors earthmovements. Crest gates, valves, pipelines andassociated equipment are regularly inspectedand maintained.

THE VALVE HOUSE, WARRAGAMBA>

PROSPECT WATER FILTRATION PLANT>How the dam works

SAFEGUARDING THE DAM

Rainfall and flood event studies showed thatthe dam could experience floods much largerthan originally estimated. As the first step in atwo–stage solution, the height of the dam wallwas increased by five metres. Work took placebetween 1987 and 1989 as the dam wall wasraised and strengthened using post–tensionedsteel cables, tying the upper portion of the wallto its base.

In early 1999 work began on stage two of thedam safety program, involving the constructionof an auxiliary spillway located on the eastbank of the dam. During rare and extremefloods, the auxiliary spillway will allowfloodwaters to pass safely around the dam,reducing the pressure on the dam wall andensuring its safety. The auxiliary spillway was

1964 FLOOD>

completed in 2002.

Prospect Reservoir is located on ProspectCreek, approximately 35 kilometres west ofSydney. The dam was completed in 1888 andwas the first earthfill embankment dam inAustralia. Its original purpose was to storewater fed by gravity from the dams of theUpper Nepean system, via the Upper Canal.

From there the Lower Canal led to a basin at Guildford, from where water was piped toseveral reservoirs around the city.

Water from the Warragamba EmergencyScheme reached Prospect Reservoir in May 1940. The water was piped acrossMegarrity’s Creek Bridge at Warragamba, and another 26 kilometres to ProspectReservoir. With the completion of WarragambaDam in 1960, Prospect Reservoir continued toplay an important role in storing Sydney’s watersupply. A second pipeline linking Warragambaand Prospect Reservoir was completed in 1966, significantly increasing the volume ofwater that could be transferred during peakdemand periods.

Prospect Dam was strengthened by theplacement of stabilising beams on thedownstream face in 1979, and the upstreamface in 1997.

With the commissioning of the Prospect waterfiltration plant in 1996, raw water transferredfrom Warragamba and the Upper Nepean damswas sent directly to the treatment facility,by–passing Prospect Reservoir.

However, Prospect Reservoir remains anintegral part of Sydney’s drinking water supplyand is required in times of high demand forwater. The filtration plant at Prospect can draw water directly from Prospect Reservoir if required, providing greater flexibility insourcing the best quality water.

Prospect Reservoir

> AERIAL VIEW OF PROSPECT RESERVOIR

It is essential that all SCA dams meet therequirements of the NSW Dams SafetyCommittee (DSC) under the NSW Dams SafetyAct (1978). The DSC, the State’s regulator fordam safety, develops and implements policiesand procedures for effective dam safetymanagement in order to protect life, propertyand the environment from dam failures.

To ensure compliance with its operatinglicence, the SCA has adopted a structuredprogram of surveillance and monitoring thatcomplies with the requirements of the DSC and national and international best practice.

Ensuring dam safety

WARRAGAMBA EMERGENCY SCHEME,Megarrity’s Bridge, and Prospect Reservoir and Value House are listed on the StateHeritage Register.

DID YOU KNOW?>

The SCA conducts extensive routine water quality and quantity monitoring in thecatchments, storages and in–flows to water filtration plants. Monitoring providesinformation to enable the best quality water to be drawn–off into the supply system, and toidentify areas requiring special catchmentmanagement attention. The SCA also conductsregular testing at several locations for thepresence of the protozoan parasites Giardiaand Cryptosporidium in the water. Informationcollected from the SCA’s monitoring programs is used for public health reportingand assessment.

MAINTAINING GOOD WATER QUALITY IN THE CATCHMENT

The SCA works with government, industry andthe community to promote good water qualityand healthy, sustainable catchments.

Extensive research is carried out by the SCA tohelp understand the catchment environment.The SCA also plays an important role inensuring that proposed land use anddevelopment is compatible with preservingwater quality.

Field staff undertake a range of on–groundactivities in the catchments, such as pestcontrol, fire control, erosion control and repair,regulating access, containing spills, chemicalcollections and weed control. In the SpecialAreas (land closest to the storages) theseactivities are jointly managed by the NationalParks and Wildlife Service and the SCA.

Many successful projects are also undertakenjointly with landholders and community groupsincluding riverbank stabilisation, willowremoval, revegetation and riverbank fencing.

ENVIRONMENTAL FLOWS

The SCA recognises that Warragamba Dam canaffect the natural flow of water downstream.Providing water to the river throughenvironmental flows is one way the SCA can help restore ecological processes andbiodiversity of water dependent ecosystems.

Currently, the SCA releases 43.3 million litres of water per day from Warragamba Dam into the Nepean River for environmental andriparian purposes.

Monitoring water quality

Fact File

WARRAGAMBA DAM

Height 142 mLength 351 mThickness at base 104 mWidth of central spillway 94.5 mConcrete mass 3,000,000 tWidth of auxiliary spillway (at mouth) 190 mLength of auxiliary spillway 700 m

LAKE BURRAGORANG

Total Capacity 2,031,000 MLArea 75 km2

Length of lake 52 kmLength of foreshores 354 kmMaximum depth of reservoir 105 mCatchment Area 9,051 km2

Average annual rainfall 840 mm

PIPELINES

Diameter 2,100/3,000 mmLength 27 km eachCapacity 2,600 ML per day

CONSTRUCTION OF WARRAGAMBA–PROSPECTPIPELINE, FEB 1966

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LAKE BURRAGORANG, WHICH IS FORMED BY WARRAGAMBA DAM

> PROSPECT RESERVOIR>WARRAGAMBA DAM WALL>

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PROSPECT DAM

Height 26mLength 2,225mTotal capacity 50,000MLCatchment 9.7km2

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Warragamba Dam is located about 65kilometres west of Sydney and is an ideal spot for picnicking, barbecuesand sightseeing.

Facilities are set in natural bushlandsurroundings and include picnic shelters,shade trees, visitor information centre,barbecues, viewing area and a children’splayground.

Visiting hours are 10am to 5pm daily (7pm onweekends and public holidays during DaylightSaving Time).

For more information telephone theWarragamba Dam Visitor Information Centre on (02) 4720 0349 (10am to 4pm daily, exceptChristmas Day and Good Friday).

For educational excursions and project material, please contact our Education Office on (02) 4720 0344/3

There are no entry fees to any of our dams. Picnic areas cannot be reserved.

TEMPORARY LIMITATIONS TO VISITORFACILITIES AT WARRAGAMBA DAM

Activities at Warragamba Dam are temporarilylimited due to upgrades to the dam andredevelopment of the recreational facilities.

will remain open to visitors during thisperiod.

wall itself and guided tours of the dam are notavailable. However, there is a viewing platformlocated at the end of Eighteenth Street, Warragamba with spectacular views of the damand the new auxiliary spillway.

Recreation at Warragamba Dam

WARRAGAMBA DAMFACILITIES

INFORMATION CENTRE

ELECTRIC BBQS

WATER

PLAYGROUND

TOILETS

DRINKING WATER

VIEWING AREA

PICNIC SHELTERS

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The Visitor Centre and limited picnic facilities

There is no public access to Warragamba Dam

Burragorang Lookout & Prospect Reservoir

BURRAGORANG LOOKOUT

Spectacular, panoramic views of LakeBurragorang can also be seen fromBurragorang Lookout, which is located near Nattai in Sydney’s south–west.Burragorang Lookout is part of the NationalParks and Wildlife Service’s (NPWS) NattaiReserves System.

PROPSECT RESERVOIR PICNIC AREA

Prospect Reservoir Picnic Area, which is owned and managed by Sydney Water, is opento the public every day of the year between10.00am and 4.45pm.

For weekends and public holidays duringDaylight Saving Time only, the picnic area remains open until 6.45pm.

Facilities include barbeques, toilets, and children’s playgrounds.

BURRAGORANG LOOKOUTFACILITIES

BBQS

TOILETS

VIEWING AREA

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PROSPECT RESERVOIR PICNIC AREA FACILITIES

BBQS

PLAYGROUND

TOILETS

VIEWING AREA

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Warragamba Dam is located on theWarragamba River about 65km west from Sydney.

How to get there

Burragorang Lookout is located nearNattai in Sydney’s south–west.

From Camden, take Druitt Lane, (which turnsinto Burragorang Road), to Nattai and continueto the lookout. From Picton, take BarkersLodge Road to Oakdale, then west to Nattai.

Prospect Reservoir

Travelling west on the M4, take the ProspectHighway exit. Turn left at the roundabout, and right at the T–intersection. The entrance to Prospect Reservoir is the second turn on the left.

If travelling east on the M4, take the ReservoirRoad exit. Turn right onto Reservoir Road. The entrance is approximately two kilometreson the right.

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Take Mulgoa Road from Penrith (or Northernand Park Roads from the south) to Wallacia,then Silverdale Road and Farnsworth Avenue to Warragamba.

About 28 per cent of the Warragambacatchment is classified as Special Area. In total, Special Areas cover about 3,700 square kilometres of land surrounding SCAwater storages.

The Special Areas protect our water supplybecause they act as a buffer zone, helping to stop nutrients and other substances that could affect the quality of water enteringthe storages.

The Sydney Catchment Authority and the National Parks and Wildlife Service (NPWS) jointly manage the Special Areas, in accordance with the Special Areas StrategicPlan of Management.

This long–term plan aims to provide highquality water in the storages, ensure ecosystemintegrity, and improve the environmental qualityof the catchment areas.

Public access to parts of the Special Areas isrestricted to protect water quality. This benefitsthe community by:• ensuring we have safe, clean water• protecting large areas of bushland

and plant and animal habitats• protecting threatened plants

and animal species• preserving evidence of Aboriginal heritage

dating back many thousands of years, and• preserving evidence of European exploration,

early settlement, and phases of developmentsuch as forestry, mining and dam building.

Restrictions and controls are placed on landuse, development and access within SpecialAreas. Activities such as swimming, fishing,boating and camping are prohibited, unlessotherwise specified.

Why Special Areas are protected

ACCESS AND THE SPECIAL AREAS

Under the Sydney Water CatchmentManagement Act 1998, there are two waterquality protection zones – Schedule One andSchedule Two. These zones are collectivelycalled the Special Areas.

Schedule One

In Warragamba catchment, Schedule One landextends in a radius of three kilometres from thetop of the stored water level in LakeBurragorang. All access, either on foot or byvehicle, and including motorcycles, bicycles andhorses, is prohibited. The only exception is anaccess corridor for walkers from Katoomba toYerranderie or Mittagong via Beloon Pass.

Schedule Two

Schedule Two is the second–tier water quality protection zone, and adjoins ScheduleOne. Vehicular access is restricted (as aremotorcyclists, bicyclists and horse riders), but walkers are generally permitted.

Fines of up to $11,000 apply for unauthorisedor illegal access in the Special Areas.

Access and the Special Areas

(no entry)

(restricted access)

How you can help keep our catchments healthy

SAVING WATER

Water is a precious resource. Each of us has aresponsibility to reduce the amount of water weuse – no matter where we live.

By reducing the amount of water we all use, wereduce the need to build expensive new watersupply infrastructure such as dams, reservoirsand pipelines.

Reducing the amount of water we all use canalso help make more water available forenvironmental flows, which protect the healthof the rivers downstream of the dams.

The need to manage demand for water isreflected in the Operating Licences of both theSCA and Sydney Water. The SCA is working withSydney Water to encourage water savingactions around the home, garden and office.

The SCA also recognises the need to adoptexemplary practices in managing our ownbusiness. Minimising leaks in pipelines andfitting water saving appliances and devices arejust some of the ways the SCA is reducing theamount of water we use.

WATER SAVING TIPS

For great water saving ideas, visit the Sydney Catchment Authority websitewww.sca.nsw.gov.au. Follow the links to sitessuch as www.sydneywater.com.au for moreinformation.

IN THE CATCHMENTS

People living and working in the catchmentareas play a special role in keeping ourcatchments healthy. Some of the ways peoplein the catchments help include: • using chemicals efficiently and carefully • controlling weeds and pests• retaining and planting vegetation to

prevent soil loss • protecting stream bank vegetation to

provide a buffer against pollution• managing on–site sewage systems effectively• encouraging and developing improved sewage

and stormwater management systems• preventing bushfires• reporting spills, and• getting involved in a Landcare, Streamwatch

or other local community group.

USING LESS WATER HELPS KEEP OUR CATCHMENTS HEALTHY

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