A FAMILIAR sight has returned to Poole Park lake as large mats of algae have developed on the water surface.

An outbreak of the unsightly and smelly green mass has spread despite the council’s regular efforts to flush the boating lake.

Parks supervisor Lucy Giles-Townsend said they would “continue to monitor the levels of algae present in the water”.

The lake has been blighted by algal blooms due to the high levels of nutrients in the sediment beneath the water.

The large numbers of geese in the park contribute to the amount of nitrogen entering the lake, boosting algae production in the warmer months.

Ms Giles-Townsend said: “Areas of shallow water are susceptible to algae. This is increased in Poole Park Lake due to the level of nutrients contained in the water, and the warm water temperature because of the heat in summer.

“Poole Park Lake has undergone research and monitoring as part of Poole’s successful Heritage Lottery Fund bid, and Borough of Poole regularly flushes the lake, on a monthly basis, to help maintain favourable conditions.”

Poole Park’s bid for £2.7million of National Lottery money was approved in July following three years of work to secure the funding.

It gave the borough the go-ahead to pursue its ambitious plans to give the Victorian park a complete overhaul.

The proposals include lake drainage and dredging to help alleviate the algae issue.

Dredging the boating lake, and the park’s two freshwater lakes, will make them deeper, hampering the summer growth of the algae.

All the dredged material will be re-used within Poole Park to restore the existing islands, create new islands and other features, or for other landscaping uses.

The average water depth of the boating lake is around one metre deep but it extends for 21 hectares, or about 35 football pitches.

The water heats up quickly, allowing bacteria to grow rapidly and form large mats of algae, which also affect the recreation use of the water.

In 2015, Bournemouth University’s Global Environmental Solutions (BUG) consulting team were funded by the HLF to research and monitor the water quality and ecology of the park’s lakes.

Their report found that all three lakes in Poole Park represented “highly degraded ecosystems” and were “characterised by poor water quality, algal blooms and problem swarms of non-biting chironomid midges.”

The report also found it would be “unrealistic to believe that the lagoon could be maintained as a low nutrient, weed free water body.”