It comprises 59 hectares of open water, reed and saw-sedge fen, and it is a shallow, brackish lake. The reed swamp consists of common reed and lesser reedmace. In summer, the swallowtail butterfly can be seen.
Boats can only use a narrow marked channel; they are discouragesd from using the broad during the winter months because of the breeding season. There is a footpath through the reserve.