For some years water soldier has dominated Thompson Water and is having an adverse effect on the ecology of the lake. It is thought to have been introduced to the site in the early 2000s, responding to nutrients that have built up in the lake from adjoining farmland. By 2010 it covered most of the lake’s surface.
The water soldier rises above the surface in the summer, reducing oxygen in the water. Coupled with having dominated and displaced other plants, the oxygen levels drop markedly and encourage anaerobic bacteria to grow, releasing hydrogen sulphide into the water. In the autumn the plants drop down to the bottom of the lake, adding more nutrients to the water as they decompose. This all impacts on the biodiversity in the lake.
We are improving water quality in Thompson Water by controlling excessive water soldier growth. This involves removing up to 1.2 hectares of water soldier each year from the lake over two years. A new work boat and tools will help us maintain the water quality after the restoration.
Removing the water soldier and creating reed fringe will not only benefit the water plants, insects, great crested newts and fish in the water, but also the birds using the surrounding habitats.
We will monitor the water quality as the project develops, which will help us with management at other sites where, in response to nutrients, the prolific growth of water soldier has been identified as an issue.