Catchment Management Plan - Hunter Water

2.5 Chichester DamCatchmentarea199km 2Damvolume21.5GL(1GL =1 billionlitres)MaximumdepthSurfaceareaAnnualrainfall37m 180ha 1300mm(UpperChichester)AreassuppliedLowerHunter,approx35% ofvolumeLand usebreakdown ofcatchment76% NationalPark, 17% rural,7% Hunter Waterfreehold (AppendixA shows how thisland is managed)Populationgrowth forecast2010-2030Current population 5 150residents, high hobbyfarm vacancy rate.Negligible populationgrowth until 2030Chichester Dam is located 80 kilometresnorth of Newcastle at the south-easterncorner of the World Heritage listedBarrington Tops National Park (Figure 10).Water from Chichester Dam is dosed withchlorine at the dam and then transportedvia a gravity pipe to Dungog, where itis further treated at the Dungog WaterTreatment Plant. Approximately half ofthe flow from Chichester is suppliedto Maitland, Cessnock and Beresfieldareas. The balance gravitates further toNewcastle, where it blends with watersupplied from Grahamstown WaterTreatment Plant. Because water is fedby gravity from Chichester it requires thelowest energy input of all sources. Watersupply from Chichester Dam is used asmuch as possible for this reason.The dam is fed by the Wangat River to thenorth and Chichester River to the north-west.• The Wangat River’s catchment is entirelyvegetated and pristine. There is very littlerecreational activity in this catchmentbecause of its difficult terrain. TheWangat catchment has been deemed byexpert panel to represent the lowest riskof pollution to drinking water.• The Chichester River’s catchment ispartially cleared for agricultural andrural residential land use. Land parcelsize is small to medium for a ruralarea. There has been an increase inholdings of hobby farms and holidayaccommodation due to the region’sbeauty and relative isolation. Thereis no intensive agriculture inthe catchment. Effluent from allproperties is treated using septicsystems. A large portion of the riveris unfenced and hence cattle are freeto graze in and around the river.There is high runoff from the area dueto the abundant rainfall and the largecatchment area. Hence, the dam is filledquickly following medium to heavy rainfalland there is little time for pathogens orturbidity to settle. There is very little datacharacterising the water quality after rainevents in the Chichester or Wangat Riversdue to the remoteness of the location.Risk assessments for this source indicatedthat pathogens, phosphorus and turbiditywere the principal issues for this system.NChichester RangeChichester State ForestBarrington TopsNational ParkChichester State ForestWangat RiverChichester RiverWilliams RiverChichester DamKEYNational ParkState ForestCatchment Boundary5 KILOMETRESFigure 10: Location and extent of Chichester catchment5 Estimate based on Australian Bureau of Statistics 2006 Census dataCATCHMENT MANAGEMENT PLAN . ssS . 001 . JUNE201015