Widewater Mitigation Pipe

What? When? Why?

People are always asking questions regarding how the water flows into Widewater Lagoon, so I hope this brief summary helps a little.

After the installation of 33 rock groynes to improve sea defences, concerns were raised by interested parties regarding falling water levels and the drying out of Widewater Lagoon. This identified the need to restore water levels as a high priority for the survival of the lagoon and its specialised species. Up until this point, the lagoon was replenished through percolation of water through the single bank, overspill of sea water, rainwater, and run off from the local houses, there being no natural inlet or outlet from lagoon to sea.

This led to a meeting in May 2003 between the Environment Agency, English Nature, Lancing Parish Council, and West Sussex County Council, which resulted in an agreement to install a piped connection to the sea to prevent the lagoon from drying out.

The mitigation pipe was installed over the winter of 2002/03. It has a valve and weir boards which can be opened or closed as nature dictates, or opened manually during hot summers if the water level drops too low. From the valve pit, there are two branches of pipe entering the lagoon.

The boards are currently set so that at tides over approximately 5.8m, water will flow through the pipe, past the valve and weir boards, and into the lagoon. Therefore, over the past few years, the weir boards have been set to maintain water height as we see it almost every day.

The current weir board settings have restored historic water levels to the satisfaction of residents and visitors, but has reduced the opportunity for the muddy conditions which encourage wading birds, However, unlike the birds, the lagoon specialist species cannot go elsewhere!

The operation of the pipe and the impacts on the lagoon are not particularly based on any sound science, but conditions are monitored and adjustments made as required.

Should you have any queries on water levels, your first contact should be directed towards Lancing Parish Council, and they will pass on to the relevant body.

Garry Purnell