More MetadataHistoric drainage is used in agricultural and farm plans, stormwater management, comprehensive planning, floodplain management, and facility planning to provide a better understanding of what previous drainage was like for a given area.  Soils were originally shown at the scale of 1:15840 and then redrafted to 1:20000; the data were redrafted a final time to fit Loudoun County's base map standard of 1:2400. Although the current data rely heavily on the original soil survey, there have been extensive alterations. The data are updated as field site inspections or interpretation changes occur. This is a copy of the drains layer as it exists on 20010208. It is meant to provide the county with a historical base for drainage.Photogrammetric updates will not occur to this layer. Data are stored in the corporate ArcSDE Geodatabase as a line feature class. The coordinate system is Virginia State Plane (North), Zone 4501, datum NAD83 HARN (vertical datum, if applicable, NAVD88), US Survey foot units.