Huon River Catchment

Huon River Catchment Contents 1. About the catchment 2. Streamflow and Water Allocation 3. Water Quality 4. River Health 1. About the catchment The Huon catchment area encompasses 3,800 km 2 of land situated in the far south east of Tasmania. The major rivers draining this catchment are the Huon River (104 km), the Picton River (52 km), the Weld River (44 km), the Denison River (30 km) and the Mountain River (24 km), all of which flow into the Huon River Estuary. Further to the south, a number of smaller rivers (Esperance, Lune, D’Entrecasteaux and Catamaran) flow into coastal estuaries at the southern end of the D’Entrecasteaux Channel. A substantial portion of the western side of this catchment lies within the Tasmanian Wilderness World Heritage Area, and is protected from major land use activities. Heading eastward from the WHA boundary, land use progressively moves from native forest harvesting, to cattle and sheep grazing and more intensive agricultural enterprises such as pear, apple and cherry production, small vineyards and specialised hobby farming. The estuaries into which these areas drain are subject to substantial aquaculture enterprises mainly focussed on salmonid production, but also to a lesser degree mussels and oysters. The main towns in the catchment are Huonville, Geeveston, Dover and Cygnet. DEPARTMENT of PRIMARY INDUSTRIES and WATER - 1 - 2. Streamflow and Water Allocation Streamflow information is 70,000 collected from two locations on the Huon River, at the township of 60,000 Judbury (station 635) and at a location further upstream above 50,000 Fryingpan Creek (station 119). 40,000 The former station is primarily used for flood warning and water 30,000 quality monitoring purposes, while 20,000 the latter is more accurately rated day) per (Megalitres Streamflow for flow monitoring. 10,000 Streamflow is also monitored in 0 the Esperance River at the Dover Jan-06 Feb-06 Mar-06 Apr-06 May-06 Jun-06 Jul-06 Aug-06 Sep-06 Oct-06 Nov-06 Dec-06 water supply intake (station Date 7200). Fig: Time series of streamflow in the Huon River upstream Fryingpan Creek (station 119) during 2006. 70,000 Total Water Allocation 60,000 The following table shows the 50,000 breakdown of water allocations in the catchment. 40,000 30,000 Total 20,000 Allocation day) per (Megalitres Streamflow Irrigation 6,282 ML 10,000 Stock & Domestic 0 438 ML Jan-06 Feb-06 Mar-06 Apr-06 May-06 Jun-06 Jul-06 Aug-06 Sep-06 Oct-06 Nov-06 Dec-06 Date Water Supply 2,946 ML Fig: Time series of streamflow in the Esperance River Other 48, 896 ML (station 7200) during 2006. Of the total licensed water allocation within this catchment, 4,463 ML is held within Water Use Restrictions constructed storages and Water restriction triggers have been developed for 54,099 ML is extracted directly several tributaries of the Huon River. These are from rivers and streams. presented below, and indicate river flows when water restrictions are normally considered. Location Trigger Mountain River at Ranelagh 6.9 ML/day Russell River at Lorkins Road 17.3 ML/day Nicholls Rivulet u/s Huon River 0.86 ML/day - 2 - 400,000 Historical Average 350,000 Current Year (2006) 300,000 250,000 200,000 150,000 Total (ML) Discharge 100,000 50,000 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Fig: Comparison of the total monthly discharge with historical average monthly discharge for the Huon River upstream Fryingpan Creek (station 119). 25,000 Historical Average Current Year (2006) 20,000 15,000 10,000 Total (ML) Discharge 5,000 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Fig: Comparison of the total monthly discharge with historical average monthly discharge for the Esperance River (station 7200). - 3 - 3. Water Quality Under the DPIW Statewide baseline monitoring network, instream sensors were maintained throughout 2006 at the following locations within the catchment: • Huon River at Judbury (station 635); and • Esperance River at Dover water supply intake (station 7200). Water temperature, electrical conductivity and turbidity are monitored continuously at both stations, while at the Esperance River dissolved oxygen is also recorded. 2 5 2 0 1 5 1 0 5 WaterTemperature C) (Deg 0 2 0 0 1 8 0 1 6 0 S/cm) µ µ µ µ 1 4 0 1 2 0 1 0 0 8 0 6 0 4 0 Electrical Conductivity ( 2 0 0 1 6 1 4 1 2 1 0 8 6 Turbidity(NTU) 4 2 0 1-Apr-06 1-Jan-06 2-Mar-06 15-Jul-06 30-Jul-06 1-May-06 13-Oct-06 28-Oct-06 16-Apr-06 15-Jun-06 30-Jun-06 16-Jan-06 31-Jan-06 15-Feb-06 17-Mar-06 12-Nov-06 27-Nov-06 12-Dec-06 27-Dec-06 14-Aug-06 29-Aug-06 13-Sep-06 28-Sep-06 16-May-06 31-May-06 Fig: Continuous instream water quality for Huon River at Judbury (station 635) during 2006; Data quality coded as: Excellent; Good ; Fair ; or Fair Estimated Data . - 4 - 2 0 1 8 1 6 1 4 1 2 1 0 8 6 4 Water Temperature (Deg C) (Deg Water Temperature 2 0 1 8 0 1 6 0 1 4 0 S/cm) µ µ µ µ 1 2 0 1 0 0 8 0 6 0 4 0 Electrical Conductivity ( Conductivity Electrical 2 0 0 2 5 2 0 1 5 1 0 Turbidity (NTU) 5 0 1 4 1 2 1 0 8 6 4 Dissolved Oxygen (mg/L) Oxygen Dissolved 2 0 15-Jul-06 30-Jul-06 01-Apr-06 16-Apr-06 13-Oct-06 28-Oct-06 01-Jan-06 16-Jan-06 31-Jan-06 15-Jun-06 30-Jun-06 15-Feb-06 02-Mar-06 17-Mar-06 12-Nov-06 27-Nov-06 12-Dec-06 27-Dec-06 14-Aug-06 29-Aug-06 13-Sep-06 28-Sep-06 01-May-06 16-May-06 31-May-06 Fig: Continuous instream water quality for Esperance River at Dover water supply intake (station 7200) during 2006; Data quality coded as: Excellent; Good ; Fair ; or Fair Estimated Data . - 5 - Periodic water sampling is also conducted at four to six-weekly intervals at three stations in the catchment. These are: • Huon River upstream Fryingpan Creek (station 119); • Huon River at Judbury (station 635); and • Esperance River at Dover water supply intake (station 7200). Sampling consists of spot measurements of selected water quality parameters on-site (water temperature, turbidity, conductivity, pH and dissolved oxygen). Bottled samples of water are also collected for analyses of Fig: Huon River upstream Fryingpan Creek. nutrients (collected monthly) and pesticides (collected quarterly) at the Analytical Services Tasmania laboratory. Links 1. Water Information System of Tasmania 3. Surface water quality DPIW website www.water.dpiw.tas.gov.au/wist/ui www.dpiw.tas.gov.au/waterquality 2. Pesticide Monitoring in Tasmania 4. ANZECC 2000 guidelines www.dpiw.tas.gov.au/ www.deh.gov.au/water/quality/nwqms pesticidemonitoring /volume1.html Huon River upstream Fryingpan Minimum Median Maximum Number of Creek samples Temperature (deg C) 4.9 9.6 16.3 12 Turbidity (NTU) 0.86 2.15 5.21 12 Electrical Conductivity ( µµµS/cm) 39.8 72.6 182 12 Field pH 5.85 6.75 7.71 12 Dissolved Oxygen (mg/L) 8.35 11.72 13.10 11 Dissolved Oxygen (percent saturation) 85.7 101.0 109.2 11 Total Nitrogen (mg/L) 0.109 0.187 0.288 12 Total Phosphorus (mg/L) <0.005 0.005 0.011 12 Dissolved Reactive Phosphorus (mg/L) <0.002 <0.002 0.004 12 Nitrate-N (mg/L) <0.002 <0.002 0.007 12 Nitrite-N (mg/L) <0.002 0.003 0.004 12 Ammonia-N (mg/L) 0.003 0.007 0.014 12 All statistics derived from periodic spot samples . - 6 - Huon River at Judbury Minimum Median Maximum Number of samples Temperature (deg C) 4.6 9.5 16.4 12 Turbidity (NTU) 1.16 2.19 3.61 12 Electrical Conductivity ( µµµS/cm) 43.7 69.4 175 12 Field pH 5.72 6.66 7.73 11 Dissolved Oxygen (mg/L) 8.19 11.92 13.30 12 Dissolved Oxygen (percent saturation) 84.1 101.8 114.0 12 Total Nitrogen (mg/L) 0.073 0.206 0.290 12 Total Phosphorus (mg/L) <0.005 0.006 0.013 12 Dissolved Reactive Phosphorus (mg/L) <0.002 <0.002 0.004 12 Nitrate-N (mg/L) <0.002 <0.002 0.008 12 Nitrite-N (mg/L) <0.002 0.003 0.004 12 Ammonia-N (mg/L) 0.003 0.007 0.012 12 All statistics derived from periodic spot samples. Fig: Huon River at Judbury - 7 - Esperance River at Dover water Minimum Median Maximum Number of supply intake samples Temperature (deg C) 2.9 9.7 14.3 13 Turbidity (NTU) 2.06 3.55 13.00 13 Electrical Conductivity ( µµµS/cm) 42 68 100 13 Field pH 5.57 6.22 7.32 13 Dissolved Oxygen (mg/L) 8.57 11.82 14.60 13 Dissolved Oxygen (percent saturation) 87.4 100.5 111.2 13 Total Nitrogen (mg/L) 0.129 0.183 0.605 12 Total Phosphorus (mg/L) <0.005 0.008 0.021 12 Dissolved Reactive Phosphorus (mg/L) <0.002 0.002 0.006 12 Nitrate-N (mg/L) <0.002 <0.002 0.002 12 Nitrite-N (mg/L) <0.002 0.002 0.005 12 Ammonia-N (mg/L) 0.002 0.006 0.032 12 All statistics derived from periodic spot samples.

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