Historic\ndrainage is used in agricultural and farm plans, stormwater management,\ncomprehensive planning, floodplain management, and facility planning to provide\na better understanding of what previous drainage was like for a given\narea.\u00a0 Soils were originally shown at the scale of 1:15840 and then\nredrafted to 1:20000; the data were redrafted a final time to fit Loudoun\nCounty's base map standard of 1:2400. Although the current data rely heavily on\nthe original soil survey, there have been extensive alterations. The data are\nupdated as field site inspections or interpretation changes occur. This is a\ncopy of the drains layer as it exists on 20010208. It is meant to provide the\ncounty with a historical base for drainage.Photogrammetric updates will not\noccur to this layer. Data are stored in the corporate ArcSDE Geodatabase as a\nline feature class. The coordinate system is Virginia State Plane (North), Zone\n4501, datum NAD83 HARN (vertical datum, if applicable, NAVD88), US Survey foot\nunits.