|
description:
|
City of London Subwatersheds represent drainage areas where water flows into bodies of water or watercourses within or nearby the City of London. The subwatersheds are derived from adjacent watershed data (administered by regional conservation authorities) and storm drain analysis (see description below). The three conservation authorities (CA) having jurisdiction in the City of London include: Kettle Creek CA (Dodd, Upper Kettle Creeks), Lower Thames Valley CA (Sharon Creek), and Upper Thames River CA (remaining subwatersheds). Fansawe Reservoir, Central London, Downstream Thames and South Thames are not actual subwatersheds, rather they are subwatershed groupings along the river corridor for management purposes. Assumptions on individual lot drainage were made without detailed subdivision grading plan information.Boundary Creation - Generally speaking, in the urban portion of the City, subwatershed boundaries were determined using the Minor Flow stormwater system controlled by storm sewers (storm road grates and subsurface drainage pipes). In the rural portion of the City where stormwater sewers do not occur, subwatershed boundaries are derived by contours illustrating landscape topography. A combination of City “sewershed” mapping and CA “subwatershed” mapping were used to complete these subwatershed maps. |