Sewardstone Marsh (Map:; OS grid reference TQ378982) is a site of about 14.5 hectares (36.5 acres) within the Lee Valley Park. Its two main areas, Knights Pits and Patty Pool Mead, provide marshland, two small lakes and a seasonally wet area.
Address: Sewardstone Marsh, Godwin Close, Sewardstone Road, London E4 7RQ
The marshes were originally grazing meadows but with the discovery of gravel for use in road building, the area was excavated during the 1939–45 war. The land was then sold to the North Metropolitan Power Station, which used the area as a dumping ground for pulverised fly ash and rubble from the nearby Brimsdown power station.
Lee Valley Regional Park Authority has owned Sewardstone Marshes since the mid-1980s, It was then surrounded by open fields and nurseries, with the Royal Ordnance Factory to the north and the Royal Small Arms Factory to the west. The site was designated a Site of Specific Special Interest because its disturbed ground and poor soils encouraged Early Marsh Orchids. Unfortunately, this delicate plant has disappeared as woodland has spread and shaded its growing sites.
The Knights Pits area consists of two pits formed as a result of gravel extraction, a large wooded area and some grassland and scrub. Patty Pool Mead, to the south of the site is a grazed meadow that regularly floods in winter and early spring. Work is taking place to improve the wetland to attract more birds. The site also includes a woodland copse and an extensive area of couch-dominated grasslands with invasive Elder and Willow scrub.
Knights Pits attracts common water birds such as Coot, Moorhen and Mallard and the surrounding water edges and wet woodland support other birds, with up to 90 species recorded annually. Patty Pool Mead regularly attracts wintering Snipe. The woodland and grassland attract breeding species such as Whitethroat, Yellowhammer and the occasional Reed Bunting. Cuckoos are regular spring visitors. Occasional visitors to the marsh include Firecrest, Goosander, Stonechat, Little Owl, Water Rail, Gadwall, Treecreeper, Fieldfare and Redwing.
The larger of the two flooded pits is a fishery, with Mirror Carp, Pike and Bream.
On the site as a whole, most of the typical Lee Valley butterfly species have been recorded. The Musk Beetle, which depends on young Willow woodland for its breeding and development, can also be found.
Visitors approaching by car should head for Sewardstone Road (A112) and park in Godwin Close. The entrance to the site is at the end of the close. Bus route 505 passes the end of Godwin Close. Pedestrians may also approach the site from Swan and Pike Pool, walking along the River Lee and across an Environment Agency bridge into the marshes. From the north, the site can be reached through Gunpowder Park or across Cattlegate Bridge from Enfield Island estate. Cyclists can reach the site by following Section 18 of the Sustrans London Loop, which passes through the marsh. The nearest railway station is Enfield Lock, which is about 30 minutes walk to the west.
Tar and chip paths allow an easy circular route around the marshes and onto Epping Forest.
Along the pathways can be found a number of benches and picnic tables to encourage visitors to relax and enjoy their surroundings. Interpretation boards are currently being developed for the site.
This page has been cobbled together, mainly from information on the Lee Valley Park website (), by someone who has never visited the site but thinks that it deserves a page because it keeps cropping up on the Latest News page. If you are familiar with the site, please correct, expand and/or update this information (and delete or amend this paragraph).