Lea Marston is a series of three purification lakes created by the Environment Agency (EA) from former gravel extraction pits. They were opened in 1980 and helped remove pollutants from the River Tame.
As the River Tame flows in to and through the wide, shallow lakes, the water flow slows, allowing pollutants to settle. These could then be removed by dredging. At it’s height, the dredging was a constant operation, removing around 15,000 tonnes of contaminated sludge per year. Following creation of the lakes, the water quality of the River Tame downstream began to improve rapidly.
Improvements in water treatment at Minworth Sewage Works, and the widespread decline in heavy industry in Birmingham, mean the lakes are no longer required for water purification. The EA is currently considering their longterm future, for people and wildlife.
There is a similar lake purification system on the River Rhur in Germany.
The lakes are of regional significance for winter wildfowl populations. There is a bird hide and walks around the lakes.