Environment Sport & Leisure

Marine Lake under threat from silt and seaweed

By Paul Johnston at

West Kirby’s Marine Lake is at risk of becoming unusable unless action is taken to tackle growing problems with silt, an invasive seaweed and the deterioration of the outer wall.

A stark council report warns it would mean the borough’s prime water sports location would be unable to host international events such as the Wilson Trophy, leave the revamped sailing centre without a lake to sail on – and even threaten the town’s status as a¬†popular visitor destination.

Wirral Council’s Assistant Director for community services, Colin Clayton, reveals there have been issues with boat propellers becoming entangled in seaweed and surfboards being grounded.

At a meeting on Thursday 28 November, the environmental overview and scrutiny committee will be asked to back a proposal to commission experts to come up with a plan to tackle the issues.

West Kirby Marine Lake

West Kirby Marine Lake

The report states: “Since the last dredging operation in 2009 there has been a build-up of windblown sand and tide-borne silt within the lake which is significantly reducing the available depth of water in many locations.

“In 2018 reports were received of an invasive species of seaweed within the lake, thought to be sargassum muticum. The seaweed has since been observed to grow rapidly during May – June and has formed large rafts of floating weed which fouls propellers and rudders of sailing craft and impedes users of the lake.

“The weed has also been observed to anchor on the wall structures that provide the boundary to the lake. The weed is dormant in the autumn & winter then awakens¬†its lifecycle in springtime.

“Inspections of the outer lake wall have identified areas of degradation thought to be as a result of marine growth anchoring into and dislodging the asphaltic bonded aggregate the forms the lining to the lake. At some locations the stone core to the wall and lake walkway can be observed.”

The council does not want the work to start around the time of the opening of the new sailing centre, in March

The council believes the weed can only be managed rather than totally eradicated, and there are concerns that emptying the lake to remove silt and seaweed “is likely to cause significant damage to the lake wall and walkway due to its current degraded condition”.

The government’s environment advisor, Natural England, is against draining the lake unless the weed can be captured and disposed of during draining, because of fears it could spread elsewhere.

Subject to council approval, a specialist marine ecology and civil engineering company will be commissioned to prepare options.

It is not yet known when work would start, but the council says it would not want it to coincide with the opening of the sailing centre and the peak season.