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.

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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 .

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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.

Fig: Esperance River at Dover water supply intake

- 8 - 4. River Health Kermandie River upstream of North Creek The Australian River Assessment System (AUSRIVAS) is a This site lies in the middle reaches of the standardised national system for Kermandie River in State Forest, approximately 5 assessment of river condition that kilometres upstream of the town of Geeveston. The uses benthic macroinvertebrates. river at this point is approximately 5 metres wide and characterised by a series of fast flowing riffles The AUSRIVAS models predict the interspersed with slower flowing runs and pools. aquatic macroinvertebrate fauna The site is surrounded by dense native vegetation that would be expected to occur with little intrusion by exotic species. However the at a site in the absence of riparian zone has recently been disturbed by environmental stress such as activities associated with the construction of pollution, habitat degradation or forestry roads. This has also led to increased flow regulation. A comparison of sedimentation within the river. Nevertheless water the macroinvertebrates expected quality remains generally good with low to occur at the test site with those conductivity and turbidity. actually collected (O/E ratio) provides a site specific measure of This site has been continuously monitored since the biological impairment of the autumn 1998 and combined season AUSRIVAS test site. Further details about assessments have consistently classed this site as AUSRIVAS can be found at: equivalent to reference (Band A) or above (Band X) with all O/E scores above 0.91. www.ausrivas.canberra.edu.a u/ausrivas. AUSRIVAS assessments are Season O/E Taxa Band O/E Taxa Band carried out at three locations in Riffle Edgewater Au98/ Spr98 1.13 A 1.08 A the Huon River catchment; Au99/ Spr99 1.14 X 0.96 A • Kermandie River upstream of Au00/ Spr00 1.04 A 1.02 A Au01/ Spr01 1.06 A 1.1 A North Creek; Au02/ Spr02 1.14 X 1.11 A • Mountain River at Ranelagh Au03/ Spr03 1.11 A 1.07 A Spr03/ Au04 0.91 A 1.03 A bridge; Spr04/ Au05 0.99 A 1.22 X • Russel River at Russel Pimple; Spr05/ Au06 1.03 A 0.95 A and • Esperance River off Esperance River Road 1.4 1.2

0.8

0.6

O/E Taxa O/E 0.4 Riffle 0.2 Edgewater

0 Au98/ Au99/ Au00/ Au01/ Au02/ Au03/ Spr03/ Spr04/ Spr05/ Spr98 Spr99 Spr00 Spr01 Spr02 Spr03 Au04 Au05 Au06 Season

Fig: Combined season AUSRIVAS O/E Taxa scores for Kermandie River upstream of North Creek.

Fig: Kermandie River upstream of North Creek.

- 9 - Mountain River at Ranelagh Bridge This site is located in the lowest from significantly impaired (Band B) to equivalent reaches of Mountain River, to reference (Band A). approximately 600 metres above the confluence with the Huon River. The site is located immediately above the Ranelagh Bridge and consists of shallow riffles and runs flowing over predominantly cobble and pebble substrate. There is aggradation of substrate in the upper part of the reach, causing some channel alteration and flow diversion, thereby exacerbating erosion of the right bank (looking downstream). Riparian vegetation in this reach has been severely reduced by Fig: Mountain River at Ranelagh bridge. farming and horticultural practices. Although discontinuous remnants of native vegetation Season O/E Taxa Band O/E Taxa Band remain, the riparian zone is Riffle Edgewater dominated by non-native species Au98/ Spr98 0.66 B 0.73 B Au99/ Spr99 0.69 B 0.74 B such as blackberries, willow, Spr03/ Au04 0.8 B 0.74 B gorse and poplars. Rehabilitation Spr04/ Au05 0.7 B 0.87 A of this site through willow removal Spr05/ Au06 0.85 B 1.07 A and revegetation has occurred below the bridge.

With the exception of slightly 1.4 elevated turbidity and 1.2 conductivity, water quality variables were within expected 1 ranges for a river of this type. 0.8 Combined season AUSRIVAS 0.6 O/E O/E Taxa assessments of the riffle habitat 0.4 have classed this site as Riffle 0.2 Edgewater significantly impaired on all occasions with losses between 15 0 Au98/ Spr98 Au99/ Spr99 Spr03/ Au04 Spr04/ Au05 Spr05/ Au06 to 35% of expected taxa. Combined season AUSRIVAS Season assessments for the edgewater habitat have shown an increasing trend in the health of this site Fig: Combined season AUSRIVAS O/E Taxa scores with O/E scores increasing from for Mountain River at Ranelagh. 0.73 in 1998 to 1.07 in spring 2005/autumn 2006. The magnitude of this increase has been sufficient to shift this site

- 10 - Russell River at Russell Pimple This site lies within State Forest in the middle reaches of the Russel River. Native vegetation dominates the riparian zone with little or no encroachment by exotic species. Visual assessments indicate some minor disturbance around the site and some sedimentation of the river around the bridge, which is attributed to road runoff. The river at this point is 7 to 10 metres wide and consists of fast flowing riffles and runs over predominantly boulder and cobble substrate. Fig: Russell River at Russell Pimple. Water quality at this site is very good with low conductivity and turbidity. Nutrient concentrations Season O/E Taxa Band O/E Taxa Band Riffle Edgewater were also low. Au98/ Spr98 1.13 X 0.99 A This site has been continuously Au99/ Spr99 0.95 A 1.01 A Au00/ Spr00 1.09 A 0.88 A monitored since autumn 1998 and Au01/ Spr01 1.08 A 1.06 A all but one of the 52 single and Au02/ Spr02 1.16 X 1.02 A combined season AUSRIVAS Au03/ Spr03 1.04 A 1.16 X assessments have classed this Spr03/ Au04 1.04 A 1.15 X site as equivalent to reference Spr04/ Au05 1.1 A 1.07 A Spr05/ Au06 1.04 A 1.08 A (Band A) or above (Band X). The spring 2003 edgewater sample yielded an O/E score of 0.66 (Band B). However this is more a 1.4 reflection of the limited amount of 1.2 edgewater habitat available for sampling in a high gradient 1 stream such as this rather than 0.8 any human impact. 0.6 O/E Taxa O/E 0.4 Riffle 0.2 Edgewater 0 Au98/ Au99/ Au00/ Au01/ Au02/ Au03/ Spr03/ Spr04/ Spr05/ Spr98 Spr99 Spr00 Spr01 Spr02 Spr03 Au04 Au05 Au06 Season

Fig: Combined season AUSRIVAS O/E Taxa scores for the Russell River at Russell Pimple.

- 11 - Esperance River off Esperance River Road This site lies within State forest in the upper reaches of the Esperance River, approximately 5 kilometres downstream of the Hartz Mountains National Park boundary. The site is surrounded by dense native forest and the riparian zone appears to be in good condition with little obvious disturbance Fig: Esperance River off Esperance River Road. except for forestry roads. Likewise, the instream habitat is in good condition and consists of Season O/E Taxa Band O/E Taxa Band fast flowing shallow riffles and Riffle Edgewater runs flowing over predominantly Au98/ Spr98 1 A NS Au99/ Spr99 1.19 X 1.24 X boulder and cobble substrate. A Au00/ Spr00 1.15 X 1.17 X large number of trees and Au01/ Spr01 1.14 X 1.16 X branches have been relocated to Au02/ Spr02 1.03 A 0.89 A the edges of the river. Au03/ Spr03 1 A 1.01 A Spr03/ Au04 0.93 A 0.95 A Turbidity, conductivity and Spr04/ Au05 1 A 1.1 A nutrient levels were all low and Spr05/ Au06 1.16 X 1.02 A indicative of excellent water quality.

Single and combined season 1.4 AUSRIVAS assessments have 1.2 indicated the site to be in very 1 good condition with only the 0.8 spring 2003 edgewater 0.6 assessment falling into the Taxa O/E 0.4 Riffle significantly impaired (Band B). 0.2 Edgewater This is thought to be due to a 0 limited amount of edgewater Au98/ Au99/ Au00/ Au01/ Au02/ Au03/ Spr03/ Spr04/ Spr05/ habitat. No assessment was Spr98 Spr99 Spr00 Spr01 Spr02 Spr03 Au04 Au05 Au06 possible in autumn 1998 due to Season insufficient edgewater habitat.

Fig: Combined season AUSRIVAS O/E Taxa scores for the Esperance River off Esperance River Road.

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