Water Quality of Rivers in the North Esk Catchment A Report Forming Part of the Requirements for State of Rivers Reporting PART 1 Authors; Katrina Berry 1 Christopher Bobbi 2 Abigail Foley 1 Water Assessment and Planning Branch DPIWE. 1 Water Assessment and Planning Branch, Water Resources Division. 2 Environmental and Resource Analysis, Hydro Tasmania. December 2003 Copyright Notice: Material contained in the report provided is subject to Australian copyright law. Other than in accordance with the Copyright Act 1968 of the Commonwealth Parliament, no part of this report may, in any form or by any means, be reproduced, transmitted or used. This report cannot be redistributed for any commercial purpose whatsoever, or distributed to a third party for such purpose, without prior written permission being sought from the Department of Primary Industries, Water and Environment, on behalf of the Crown in Right of the State of Tasmania. Disclaimer: Whilst DPIWE has made every attempt to ensure the accuracy and reliability of the information and data provided, it is the responsibility of the data user to make their own decisions about the accuracy, currency, reliability and correctness of information provided. The Department of Primary Industries, Water and Environment, its employees and agents, and the Crown in the Right of the State of Tasmania do not accept any liability for any damage caused by, or economic loss arising from, reliance on this information. Preferred Citation: DPIWE (2003) State of Rivers Report for the North Esk Catchment. Water Assessment and Planning Branch, Department of Primary Industries, Water and Environment, Hobart. Technical Report No. WAP 03/06 ISSN: 1449-5996 The Department of Primary Industries, Water and Environment The Department of Primary Industries, Water and Environment provides leadership in the sustainable management and development of Tasmania’s resources. The Mission of the Department is to advance Tasmania’s prosperity through the sustainable development of our natural resources and the conservation of our natural and cultural heritage for the future. The Water Resources Division provides a focus for water management and water development in Tasmania through a diverse range of functions including the design of policy and regulatory frameworks to ensure sustainable use of the surface water and groundwater resources; monitoring, assessment and reporting on the condition of the State’s freshwater resources; facilitation of infrastructure development projects to ensure the efficient and sustainable supply of water; and implementation of the Water Management Act 1999, related legislation and the State Water Development Plan. ii State of Rivers Water Quality of the North Esk Catchment TABLE OF CONTENTS EXECUTIVE SUMMARY .......................................................................................................V A GLOSSARY OF TERMS ..................................................................................................VII Units and Conversions........................................................................................................................................ ix Acronyms............................................................................................................................................................. ix B SUMMARY OF NATIONAL GUIDELINES FOR WATER QUALITY.......................................................... x Primary contact ......................................................................................................................................................... xi Secondary contact...................................................................................................................................................... xi WATER QUALITY OF THE NORTH ESK CATCHMENT 1 1 HISTORICAL AND OTHER DATA .................................................................................... 1 1.1 Chimney Saddle & Distillery Creek Water Quality ......................................................................................... 1 1.2 Tamar River Sediment Study ............................................................................................................................. 5 1.3 Launceston City Council monitoring................................................................................................................. 7 1.3.1 Time series Analysis……………………………………………………………………………………….. 7 1.4 Analysis of Water Quality in Response to Forest Harvesting in the Musselboro Creek Catchment. ........ 10 1.5Historical Data from the State database HYDROL.......................................................................................... 11 1.6 Launceston Waterwatch – St Patricks River Monitoring .............................................................................. 16 2 CURRENT STUDY........................................................................................................... 20 2.1 Physico-chemical properties ............................................................................................................................. 23 2.1.1Water Temperature…………………………………………………………………………………………. 23 2.1.2 In-stream pH……………………………………………………………………………………………….. 25 2.1.3 Electrical Conductivity……………………………………………………………………………………. 26 2.1.4 Turbidity……………………………………………………………………………………………………. 28 2.1.5 Dissolved Oxygen…………………………………………………………………………………………..30 2.2 General Ionic Composition ............................................................................................................................... 33 2.2.1 Sulphate……………………………………………………………………………………………………...36 2.2.2 Apparent Colour…………………………………………………………………………………………….36 2.2.3 Suspended Solids…………………………………………………………………………………………...37 2.3 Nutrients............................................................................................................................................................. 38 2.3.1 Total Nitrogen……………………………………………………………………………………………….38 2.3.2 Nitrate Nitrogen…………………………………………………………………………………………….39 2.3.3 Ammonia Nitrogen………………………………………………………………………………………….41 2.3.4 Phosphorus………………………………………………………………………………………………….42 2.4 Catchment Surveys............................................................................................................................................. 44 2.4.3 Catchment Survey – Total Nitrogen………………………………………………………………………..44 2.4.4 Catchment Survey – Total Phosphorus……………………………………………………………………..47 2.4.2 Catchment Survey – Heavy Metals…………………………………………………………………………51 2.4.5 Catchment Survey – Bacteria………………………………………………………………………………..57 2.5 Nutrient Load Estimates .................................................................................................................................... 61 2.5.1 North Esk at Ballroom……………………………………………………………………………………... 61 2.5.2 North Esk at Corra Linn……………………………………………………………………………………. 66 2.5.3 ‘Snapshot’ Flood Sampling………………………………………………………………………………….70 2.6 Diurnal Water Quality Variations .................................................................................................................... 73 2.6.1 Temperature…………………………………………………………………………………………………73 iii State of Rivers Water Quality of the North Esk Catchment 2.6.2 Dissolved oxygen……………………………………………………………………………………………75 2.6.3 pH……………………………………………………………………………………………………………79 2.6.3 Conductivity…………………………………………………………………………………………………81 3 SUMMARY AND COMMENTS ........................................................................................ 83 4 REFERENCES................................................................................................................. 86 APPENDIX 1. ....................................................................................................................... 88 iv State of Rivers Water Quality of the North Esk Catchment Executive Summary The North Esk Catchment is used extensively for agriculture and forestry and provides domestic water supply for Launceston. The catchment is approximately 1,065 km² and is composed of two major drainage systems, the North Esk River and the St Patricks River. The North Esk River originates in the foothills of the Ben Nevis and Ben Lomond Ranges travelling south though forestry plantations until it reaches the confluence of the Ford River where it turns west draining dispersed agricultural pastures. The smaller tributaries of Burns Creek, Musselboro Creek, Weavers Creek, Pig Run Creek and River O’Plain Creek contribute flow to the North Esk River before it reaches the confluence of the St Patricks River where flow dramatically increases. The offtake for the Esk Waters Chimney Hill Water Treatment Plant is located upstream of the confluence with the St Patricks River. The North Esk River then continues in a westerly direction through a predominantly agricultural landscape receiving flows from Roses Rivulet. As the North Esk continues west through the city of Launceston it receives flow from the partially urbanised Distillery Creek region and the heavily urbanised region of Kings Meadows Rivulet before it discharges into the Tamar River. The head waters f the St Patricks River originate between the foot hills of Mount Maurice and Ben Nevis. The St Patricks River flows through a landscape dominated by forestry operations and dispersed grazing picking up contributing flows from Camden Rivulet. Travelling in a north westerly direction the river hooks around the foothills of Mount Barrow and flows in a south westerly direction through primarily