Lake George Flow Restoration Feasibility Study

Since the South East Drainage Network construction, the hydrology of Lake George has relied upon inflows of freshwater from Drain M to fill in winter, providing short-term (annual) water level resilience to maintain the health of Lake George.

The discharge from Drain M has declined due to reductions in rainfall and land use change over the last 25 years. Flows into Lake George from the drainage catchment of Drain M has reduced by 75pc since the 1980’s, resulting in low water levels, exposing the lake to fish loss, eutrophication and dominance by algal blooms. Annual or biennial filling of the lake no longer occurs as it did in the 1980s and filling events are now rare, and have occurred only three times in the last 20 years.

Lake George has recently recovered from 16 years of eutrophication following a flushing event from the drainage network and connection to the sea. This rare flushing flow occurred following an extended period of low flows being delivered to the lake from Drain M.

The Lake George community recognises the importance of maintaining water levels in the lake to maintain its resilience and capacity to provide aquatic habitat and are seeking to investigate the feasibility of connecting elements of the Reedy Creek Mt Hope Drain to Drain M to supplement flows to the lake.

Work to date has identified there is a surplus of water available from the Reedy Creek Mt Hope Drain that is currently discharged to the sea at Southend via the Lake Frome Outlet Drain. The Limestone Coast Landscape Board is undertaking preliminary investigations to assess the hydrological and engineering feasibility of supplementing drainage flows in Drain M with diversion of flows from the Reedy Creek Mt Hope Drain. This project focuses on the engineering feasibility assessment.

These investigations are funded by the Limestone Coast Landscape Board and the Department for Environment and Water to inform the community, Lake George Management Committee and the South Eastern Water Conservation and Drainage Board.

For more information, please contact Limestone Coast Landscape Board Project Lead Mark de Jong - Mark.dejong@sa.gov.au.