Land, water and air

Water Quality and the Stream Watch Project

Holiday makers at East Head or West Wittering
Holiday makers at East Head

IThroughout most of the year the water in Chichester Harbour passes the minimum quality standards and many areas were better than that.

Water quality is also important so that the shellfish harvested from the Harbour are safe to eat.

A recent study by the Environment Agency suggested that 92% of the substances (nutrients) affecting water quality enter the Harbour from the Solent. When nutrient levels rise, there is excessive growth of algal weed which smothers environmentally sensitive saltmarsh and mudflat and causes problems for sailors as well as smelling unpleasant when it starts to decompose.

Two nutrients in particular affect algal growth, phosphates and nitrates. These are normally present in the environment but pollution can lead to unnaturally high levels.

The biggest contribution to nitrate pollution in the harbour is probably from agriculture whereas domestic waste water is thought to be the main cause of raised phosphate levels.

See the latest water quality test results from Chichester District Council.

Working in the stream
Working in the stream

The Stream Watch Project

The Streamwatch Project took place between 2004 - 2007. In association with local schools, freshwater streams running into the harbour were tested on a monthly basis. The data was collected and made available for schools to use for analysis.

For more information on the project please contact the Education Office.


Stream watch cross section
Stream watch cross section

Sewage treatment

A potential threat to water quality comes from point sources such as sewage treatment works.

Southern Water is spending large amounts of money on improving wastewater treatment, but pollution from sewage can still be a problem partly due to the rising population in the area but also due to drought, which results in less dilution of the discharge from treatment works. Many sewage treatment works are currently still not able to reduce phosphate and nitrate levels in wastewater.

Sewage is the biggest contaminant now of surface water, closely followed by oils & fuels. Other common pollutants include inert materials, waste materials, chemicals and agricultural materials and wastes.

Three sewage treatment works discharge into the Harbour.


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Chichester Harbour Conservancy Education
Harbour Office, Itchenor, Chichester, PO20 7AW.   Tel: 01243 512 301