Widewater Lagoon Mitigation Pipe

Lancing Parish Council are the owner and in conjunction with the Widewater lagoon Local Nature Reserve (LNR) Steering Committee, are responsible for managing the LNR. 
 
West Sussex County Council acts in an advisory capacity to Lancing Parish Council and the LNR Steering Ctte. West Sussex County Council does not have a warden who is responsible for the management of Widewater Lagoon. 
 
Routine Monitoring
West Sussex County Council undertake the routine monitoring of the lagoon on behalf of Lancing Parish Council this monitoring includes salinity and water levels. Routine monitoring occurs at least once a month in the winter and occurs more frequently in the summer, should it be required by the conditions of the Lagoon.  All routine monitoring data is recorded.
 
Mitigation Pipe and Water Levels
The mitigation pipe was built in 2003 following improvements in the sea defences by the Environment Agency. The mitigation pipe was designed to simulate the natural wetting cycle of the lagoon which occurred before the sea defences were improved. The mitigation pipe works by letting in sea water to “top up” the lagoon on certain high tide cycles.
 
Over the year the site will hold more water / less water dependent on the season and the high tide cycles, and these water levels may vary year to year. As such the level of mud exposed by lower water levels may also vary season to season / year to year.
 
The pipe was not designed to keep the lagoon full of water, or at one continuous water level. Routine monitoring of water levels is undertaken.
 
The mitigation pipe is managed by the Environment Agency (EA). Earlier in the year the EA undertook routine maintenance to remove the build-up of shingle from the mitigation pipe weir chamber.  The EA have also undertaken an inspection of the sea ward side (in-flow) end of the mitigation pipe and will be removing plant material and build-up over the course of this coming week, in readiness for next week’s high tide cycle.
 
Salinity levels
Salinity (salt) levels are monitored within the lagoon. The salinity levels play an important role in the maintenance of the lagoon as a hyper-saline lagoon i.e. the water in the lagoon is in places more salty than sea-water. This hyper-salinity is a specialist marine environment and a number of hyper-saline specialist animals have been recorded living within Widewater lagoon. The routine monitoring of salinity is undertaken.
 
Adjusting water levels
Within the mitigation pipe, there is a mechanism of penstock boards which can be manually adjusted to increase flow of water into the lagoon. Adjustment of the penstock boards is only undertaken based on a number of variables including routine monitoring, tide cycle and with further advice from the EA. Any decision to adjust the penstock boards is made collaboratively with LPC, WSCC and the EA. The EA operate the penstock valves. Since the pipe installation in 2003 this additional adjustment has only occurred once in 2007.

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