English: Thamesmead: Gallions Canal Large parts of Thamesmead are on land originally contaminated by the activities of the former Woolwich Royal Arsenal. The land was first recovered by the GLC for residential use in the 1960s. As part of this redevelopment a system of canals and lakes were built in order to store and manage surface water run-off prior to its discharge into the River Thames. As part of the current development Tilfen Land Limited have retained and rebuilt sections of the old system, again to manage surface water run-off, including the provision of flood storage areas, but also to provide an ecology corridor and a public amenity through the residential areas. There is a .pdf file describing the scheme on Tilfen's website here http://www.tilfenland.co.uk/pdf/reshapingenvironments.pdf This image was taken from the east side of Delisle Road with New Acres Road on the right. It is difficult to categorize the photo on the Geograph site in the sense that it is not an old navigable canal, nor a river, but an artificial drainage cut. "Drain" in the sense of a fenland drain therefore seems most suitable.