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Archived water quality assessments

Water quality within the Inman Estuary is assessed as being in good, moderate or poor condition by interpreting water chemistry and algal (chlorophyll) data. >> More

Water quality classification for October 2005 to March 2006

Indicator	Ecosystem
Ammonia	Poor
Oxidised Nitrogen	Moderate
Total Nitrogen	Poor
Soluble Phosphorus	Poor
Total Phosphorus	Poor
Turbidity	Poor
Chlorophyll a	Poor

NA = not applicable

Historically, discharge from the Victor Harbor WWTP has been the most significant source of nutrients in the estuary. Effluent has been discharged from the treatment plant for over 30 years (since 1972). The treatment process was significantly improved in November 2005. It is now likely that main influence on water quality is sediment at the bottom of the estuary. The sediment has become lacking in oxygen due to many years of WWTP discharge, and is now releasing large amounts of nutrients into the water resulting in all parameters being consistently classified as moderate or poor.

Other sources of nutrients can be fertilisers or animal wastes being washed off rural land during storms.

Water quality classification for April to September 2005

Indicator	Ecosystem
Ammonia	Poor
Oxidised Nitrogen	Poor
Total Nitrogen	Poor
Soluble Phosphorus	Poor
Total Phosphorus	Poor
Turbidity	Poor
Chlorophyll a	Poor
Heavy Metals	Poor
Bacteria	NA

NA = not applicable

The amount of nutrients can be increased by fertilisers or animal wastes being washed off farms during storms or due to effluent outfalls from the Victor Harbor WWTP. The excess nutrients can cause algal blooms and increase turbidity.

Historically, discharge from the Victor Harbor WWTP has been the most significant source of nutrients in the estuary. Effluent has been discharged from the treatment plant for over 30 years (since 1972). The treatment process was significantly improved in November 2005. It is now likely that main influence on water quality is sediment at the bottom of the estuary. The sediment has become very anaerobic due to many years of WWTP discharge, and is now releasing large amounts of nutrients into the water.

This page was last modified 31-07-2007