Maintaining the wetland at Morden Hall Park
The wetland has been a feature at Morden Hall Park for many years. The erstwhile owner of the estate, Gilleat Hatfeild, mentioned marshy ground in the North Park in his records. Originally this wetland was gravel beds and it then became the marshy ground we have today.
Wetlands are valuable because there are some species adapted to live only in this habitat. Wetlands are threatened and rare in London and are one of the National Trust’s priority habitats. Morden Hall Park's wetland is uniquely diverse for such a small area. Ongoing maintenance work is vital to ensure this diversity is preserved.
Wetlands are largely a man-made habitat. If we don’t cut them back, trees encroach and reclaim the land and the area becomes a carr woodland (wet woodland). While maintaining the wetland, we want to create a diverse mosaic of habitats and heights and manage the area to best support the flora and fauna resident in the area.
Within the wetland at Morden Hall Park we have sedge beds and reed beds. The sedge beds are cut every two years and the reed beds every eight years. Sedge, because it is thicker, needs machinery to cut, but this year for the first time we’ve cut both reed and rush with heavy horses. Using heavy horses reduces the environmental impact of the cut as well as supporting a rare breed.
Any work that we do has to take account of the natural features of the land. There’s a big ditch going through the middle and emptying into the River Wandle, which means when we drain the wetland to begin the cut we have to drain whole lot in one go. This fact imposes time pressure on maintenance; we don’t want to drain for too long so as not to unduly stress the flora and fauna living there.
In the new year, while the wetland is drained, we’re creating new water habitats by digging new scrapes. A scrape is a shallow depression around a foot deep. We’re using the opportunity to enhance the habitat in as many ways as possible while drained, including coppicing scrub.