Photo: Itchenor and Harbour Master’s office

There are three Waste Water Treatment Works (WWTW), at Appuldram, Bosham and Thornham, that discharge treated effluent into Chichester Harbour.

These WWTW have recently been upgraded so that all sewage now receives Ultra Violet and bacteriological treatment and nutrient stripping before it is discharged into the harbour. Since this work was completed on 1 April 2008 water quality monitoring has shown that the water quality in all parts of the harbour is consistently excellent (Guideline Standard) or good (Mandatory standard) measured against the European Bathing Water Directive.

However, when there are heavy storm water or high groundwater conditions the WWTW may not be able to cope with the volume of water entering the system and in these case diluted sewage which has only received primary treatment (removal of unsightly solids) may be discharged into the harbour. In these circumstances and depending on the volumes released and other factors, water quality may be reduced for the duration of the discharge and for about the next two to four days. Water quality, measured against the Bathing Water Directive, may be poor for this period particularly in the vicinity of the discharge point.

When water quality is poor, measured against the Bathing Water Directive, the advice from Chichester District Council, the Environmental Health Authority, is: Full immersion is not recommended and all cuts, open wounds and abrasions should be covered with a waterproof dressing. Normal hygiene measures are encouraged where physical exposure to water occurs. (eg wash hands before eating).

The telemetry at the WWTW records actual storm water discharges and it is not an ‘early warning alert’. Nonetheless, the Conservancy has decided that harbour users should be advised when storm water discharges have occurred. This will be done in future by e-mail and will be placed on the Conservancy’s website www.conservancy.co.uk/wind/water_quality.asp where the results of water quality monitoring are also placed.

The Conservancy gives this advice in the context that water quality in the harbour is now better than it has been for many years and there have been no recorded incidents of fatalities in the harbour caused by poor water quality and there is currently no medical evidence linking water quality in the harbour to illness.

This information comes from Chichester Harbour eNews