Chichester Harbour: Southern water storms last 650 hours

There is an ongoing spill that may have affected water quality in Chichester Harbour, according to data from Southern Water.

It has been running since 9am December 23rd and has totaled 653 hours at the time of writing.

Local residents describe the situation as “unprecedented”.

Southern Water said its storm weirs are essential to prevent flooding and other damage to homes during heavy rainfall.

A Southern Water spokesman said: “The high levels of rainfall we have seen since November have put additional strain on our sewer network as surface water has regularly entered this system in large quantities.

“To protect homes, schools and businesses from flooding, storm weirs provide a bleed valve to allow excess flows to escape to the environment instead.

“These discharges contain up to 95 percent rainwater and are approved by the Environment Agency.”

The water company said rainfall was above average during this period, meaning longer storm overflows like that at Chichester were required.

For example, data from the Wiggonholt weather station in West Sussex showed that in November 2022 there was 258.8 mm of precipitation.

The average for November is 104.65 mm.

January data is incomplete, but so far the station has already recorded 13mm more precipitation than expected for the entire month.

The spokesperson added: “However, we know this is not an acceptable system going forward and as part of a £2bn investment in our network between 2020 and 2025 we are working hard to reduce our reliance on storm surges .

“We are doing this through a combination of innovative engineering and nature-based solutions, supported by close partnership working and a focus on slowing the flow of precipitation into our sewers.

Our recently released annual bathing water update details how we are working to create healthier rivers and seas.”