Durleigh wetlands driving water quality improvements

• Natural habitats helping to substantially reduce chemicals and boost water quality at Somerset reservoir
• As World Wetlands Day is celebrated, project continues to drive big drops in ammonia and phosphorus in nearby water courses
• Biodiversity increases by up to three-quarters and continues to climb as Wessex Water maintains push towards nature-based solutions

Newly-built wetlands next to Somerset’s Durleigh Reservoir are delivering significant biodiversity and water quality improvements as Wessex Water continues its industry-leading drive to find nature-based solutions to tackle some of our foremost environmental challenges.

The two new habitats, constructed to the west of the water treatment centre and reservoir near Bridgwater, have brought about a near-75 per cent reduction in the amount of ammonia present in water, while phosphorus and sediments have dropped by around a third.

As World Wetlands Day is celebrated on 2 February, the findings have also revealed that reverting cultivated land to a natural state as well as restoring the river to its former location and reconnecting it to its floodplain has resulted in the biodiversity in the surrounding river and land habitats increasing by between 55 and 76 per cent, according to measurements calculated through the Natural England Biodiversity Metric.

This is set to increase as the habitats mature, with Wessex Water regularly sampling and analysing the wetlands that were constructed as part of a three-year £50 million refurbishment of the Durleigh Water Treatment Centre, which was returned to operation in late 2022.

Based at the head of the reservoir, the wetlands have been designed to filter silt and coarse sediment and reduce levels of nutrients, helping to improve the raw water quality entering the reservoir as well as boosting biodiversity by becoming home to a diverse array of wildlife. An existing wet woodland also acts as a final screening process before the water reaches the reservoir.

Durleigh’s now-rebuilt water recycling centre had previously suffered with poor raw water quality, deteriorating over decades, with the wetlands supporting the revamped treatment processes to ensure the site could continue to deliver the highest quality drinking water to thousands of customers in the region.

Link to Wessex Water news item.