Summary Statement:

This metadata summary applies exclusively to the data as it appears in this Loudoun County intranet/internet mapping application. To see the fully FGDC compliant version of this metadata click here.

Abstract:

The Limestone Overlay District (LOD) is a zoning overlay district adopted by the Loudoun County Board of Supervisors on 2/17/2010 and administered by the Loudoun County Department of Building and Development. The Department is responsible for all development approvals, review procedures, modifications and density calculations in the LOD as governed by Article VI, "Development Process and Administration", of the Revised 1993 Zoning Ordinance, and procedures in Chapter 8 of the Facilities Standards manual. LOD is generally comprised of the following geologic formations: Cf-Frederick Limestone, Ct-Tomstown Dolomite, JTRc-Catharpin Creek Formation, JTRcg-Catharpin Creek Formation Goose Creek Member, TRbl-Balls Bluff Siltstone Leesburg Member, and TRbs-Balls Bluff Siltstone Fluvial and Deltaic Sandstone Member. The geographic area of the Limestone Overlay District (LOD) is generally east from the Catoctin Mountain Range to the Potomac River (excludes Lost Corner), and from just south of the Town of Leesburg north to Point of Rocks, MD (excludes the Town of Leesburg.)

Purpose:

The land area delineated by the boundaries of the LOD is comprised of limestone and "Karst terrain" areas. The terrain is also characterized by the presence of certain natural features, such as sinkholes and rock outcrops. Thus, development on Karst terrain has a direct correlation to the potential for collapse and ground slippage and the susceptibility of groundwater and surface water pollution, and spring contamination, posing serious risks to public health, safety and welfare. The provisions of Section 4-1900 of the Revised 1993 Zoning Ordinance are intended to regulate land use and development in areas underlain by limestone and in areas with Karst features and terrain as shown on the official Limestone Overlay District Map of Loudoun County.

Supplemental Information

The geology of Loudoun County, Virginia, was mapped from 1988 through 1991 under a cooperative agreement between the U.S. Geological Survey (USGS) and the Loudoun County Department of Environmental Resources. This geologic map was compiled in 1993 from a series of detailed published and unpublished field investigations at scales of 1:12,000 and 1:24,000. Some of these same data were compiled as a digital geologic map at 1:100,000 scale (Burton and others, 1992a) and were the basis for a cost-benefit analysis of the societal value of geologic maps (Bernknopf and others, 1993).

A 200' buffer was added to the western edge of the largest feature. The two smaller features, to the nothwest, received 200' buffers around the entire feature. Several donut holes were removed/filled in on the largest feature. Areas outside of County jurisdiction, such as the Town of Leesburg, were removed.

Data are stored in the corporate ArcSDE Geodatabase as a polygon feature class. The coordinate system is Virginia State Plane (North), Zone 4501, datum NAD83 HARN.

Maintenance and Update Frequency:

As Needed

Data Owner:

Department of Building and Development