Water Use and Reuse Stream Projects

Protecting the Blue Lake from land use impacts

Introduction

This research program assesses the impact of urban and agricultural land use on the water quality of Blue Lake. Blue Lake is a groundwater fed volcanic crater lake that provides Mount Gambier’s potable water supply and is also an important tourist attraction in the region. Contaminants can be delivered to the unconfined Gambier Limestone aquifer via infiltration through the unsaturated zone and from stormwater drainage bores discharging directly into the aquifer. Furthermore, the karst nature of the Gambier Limestone aquifer provides the potential for contaminants to be delivered rapidly to the Blue Lake. This program is funded through the Centre for Natural Resource Management’s National Actional Plan for Salinity and Water Quality. It extends previous work undertaken by CSIRO in the Assessing and Improving the Sustainability of Urban Water Resources and Systems (AISUWRS) project, jointly funded by the EC and DEST (2003-2006)

Objectives/Scope

A risk assessment based on the Hazard Analysis and Critical Control Point (HACCP) framework within the Australian Drinking Water Guidelines allows both the health and environmental risks of contamination to be considered and incorporates the potential for natural attenuation within the aquifer and the Blue Lake. Management options can then tailored to the activities and pathways deemed to pose the greatest risk to the quality of Blue Lake.

Activities

• Use of environmental and applied tracers to estimate the minimum travel time within the saturated system
• Production of an urban land use map identifying activities deemed as posing risk to the quality of Blue via infiltration or discharge of surface runoff
• Analysis of lake sediments to understand the potential for in-lake processes to attenuate contaminants
• Development of a risk assessment consistent with the Australian Drinking Water Guidelines to assess the impacts of land use and possible management options on the quality of water in Blue Lake

Key CSIRO Staff

• Joanne Vanderzalm, Peter Dillon, Declan Page, Karen Barry, Peter Cook, John Dighton, Sébastien Lamontagne, Steve Marvanek (CLW)

Partners

• South East Natural Resource Management Board
• South Australian Water Corporation
• South Australian Environment Protection Authority
• South Australian Department of Water, Land and Biodiversity Conservation
• City of Mount Gambier
• SARDI Sustainable Farming Systems

Timeline

2003-2007