GELLIBRAND River estuary volunteers learnt more about their stream’s failing health at a meeting in Princetown.
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Associate Professor John Sherwood, an environmental scientist, gave a talk to Gellibrand River Estuary Watch, Waterwatch and Princetown Landcare groups about the waterway’s rich and diverse ecosystem.
Long-time estuary volunteer and Gellibrand EstuaryWatch group monitor Judy Spafford said the river was under stress.
Dr Sherwood explained this was due to decreased rainfall and water extraction upstream.
“The problem is the river is not doing well because it hasn’t got as much water in it,” Ms Spafford said.
Dr Sherwood said low flow from upstream could result in large bars blocking the mouth, reducing the water’s oxygen level and leading to concentrations of toxic compounds with disastrous consequences for fish and river health.
River openings at this time had caused massive fish kills and any artificial opening must be carefully managed, Ms Spafford said.
Community volunteers have been working with government agencies including the Corangamite Catchment Management Authority (CCMA) to monitor the system once a week for seven years.
“Both the EstuaryWatch and Waterwatch volunteers have been producing valuable baseline data that has been helpful with the management of this issue and were extremely grateful for this opportunity to gain more knowledge,” Ms Spafford said.
“What’s happening is the community is working with government trying to produce objective data to help with planning for the river and any future artificial opening.
“The CCMA people have been fantastic.
“They are empowering the community to have some credible input.”
The behaviour of the estuary has been documented in a report produced by CCMA called Data Analysis and Interpretation — Gellibrand River Estuary 2007-2012.
The report includes data about river mouth observations, dissolved oxygen, salinity, temperature and turbidity, some of it collected by the EstuaryWatch volunteers over that period of time.
