Inman Estuary

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Introduction

The Inman Estuary is the interface between the inland fresh water of the Inman River and the salt water of the ocean. Land uses in the catchment include dairy farming, forestry, horticulture and grazing. The Inman River receives effluent from the SA Water Victor Harbor wastewater treatment plant (WWTP), as well as stormwater from Victor Harbor and two caravan parks located on its shore. >> Map (983KB PDF)

Water quality assessment

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

Water quality classification for April to September 2006

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

NA = not applicable

The water quality monitoring results for this period were generally consistent with previous seasonal results for this site.

The nutrients in the Inman Estuary are at very high concentrations. 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 the sediments at the bottom of the estuary. The sediments have a large amount of decaying organic matter due to many years of WWTP discharge and they are now releasing nutrients into the water resulting in nutrients being consistently classified as moderate or poor. The chlorophyll (a) levels are also high, indicating that large amounts of algal growth has been occurring due to the large nutrient availability. The turbidity level is high, which is probably caused by the algae in the water.

Other sources of nutrients can be fertilisers or animal wastes being washed off rural catchments during storms. The effects of diffuse pollution in catchment runoff is more clearly seen at the Inman River upstream of the estuary, where nutrient concentrations are lower although there are clear seasonal trends.

>> Archived results

Download water quality graphs

• Ammonia in the Inman Estuary
  
• Oxidised Nitrogen in the Inman Estuary
  
• Total Nitrogen in the Inman Estuary
  
• Total Phosphorus in the Inman Estuary
  
• Soluble Phosphorus in the Inman Estuary
  
• Turbidity in the Inman Estuary
  
• Chlorophyll (a) in the Inman Estuary

Download water quality data

• Water Quality in the Inman Estuary Site 1
• Water Quality in the Inman Estuary Site 2

What is being done to improve the condition of the Inman Estuary?

The EPA and SA Water have prepared an environment improvement plan and have upgraded the Victor Harbor WWTP to reduce the amount of nutrients entering the Inman River. The EPA is working closely with the Adelaide and Mount Lofty ranges NRM board to help reduce diffuse pollution from entering the estuary and the higher reaches of the Inman River.

Links

The Department of Water, Land and Biodiversity Conservation
Natural Resource Management Boards
Department for Environment and Heritage (SA)

This page was last modified 18-12-2007