Based on the location context (United Kingdom, at Marine Lake), the snippets point most strongly to the Marine Lake at Weston-super-Mare in North Somerset.

Marine Lake sits on Weston-super-Mare's seafront, occupying a small cove near Knightstone Island at the northern end of Weston Bay.

A retaining wall known as Knightstone Causeway holds water in the lake at all states of the tide — essential given that the Severn Estuary has one of the highest tidal ranges in the world.

Sluice gates in the causeway periodically filter the lake, while high tides overtop the wall to replenish it with fresh seawater from the Bristol Channel.

The lake is a free, year-round destination for outdoor swimming and non-powered watersports, used daily by people of all ages. Water temperatures range on average from around 3 °C in winter to 19 °C in summer.

Madeira Gardens, situated above the lake, offer shade and views across the estuary.