Section 5.05
Dimensional standards
Servicing
- Geographic extent
- Areas underlain by limestone and with Karst features and Karst terrain
Uses
Prohibited6
- Facilities or uses that generate or manufacture hazardous substances
- Storage of hazardous substances in an aggregate amount greater than 55 gallons (or dry weight equivalent) on site at any one time, excluding heating oil or gasoline within above ground storage tanks
- Automotive Use Category uses identified in Section 3.02
- Underground storage tanks, except for propane tanks and water cisterns shown on an approved Geophysical Study
- Waste-related Use Category uses identified in Section 3.02
- Convenience store (with gasoline sales)
Extracted standards
13 individual requirements pulled out of this section’s prose, each with the sentence it came from.
Grading
- GradingGrading (cut & fill)Reshaping land by removing earth (cut) or adding it (fill), often capped by volume. permit required for all land disturbing activities
A grading permit is required for all land disturbing activities.
Other
- Public sewer or community wastewater systems required for subdivisions of 15+ lots15 lots
Public sewer or community wastewater systems designed in accordance with applicable Loudoun Water standards are required for all subdivision of 15 or more lots approved after February 17, 2010, except for subdivisions in which each lot of the subdivision contains 10 or more acres of land or if the applicant demonstrates to the County that other types of systems are available that will achieve and maintain the same or superior treatment results.
- Community water supply required for subdivisions of 15+ lots15 lots
Community water supply systems are required for all subdivisions of 15 or more lots approved after February 17, 2010, except for subdivisions in which each lot of the subdivision contains 10 or more acres of land.
- Expansion of existing structures/imperviousImpervious coverageThe share of a lot covered by anything water cannot soak through — roofs, drives, patios. surfaces25 pct
Such alteration does not increase the total footprint of a structure, or increase total impervious surface area (exclusive of existing structures), as it existed on February 17, 2010, by more than 25% or 2,000 square feet, whichever is greater
- Hazardous substance storage limit55 gallons
Storage of hazardous substances in an aggregate amount greater than 55 gallons (or the dry weight equivalent) on site at any one time, excluding heating oil or gasoline within above ground storage tanks
- Irrigation systems prohibitedProhibitedNot allowed in the district at all, short of rezoning or a variance. unless water from non-groundwater source
Irrigation systems are prohibited unless the water for such system is supplied from a source that is not dependent on groundwater, such as, but not limited to, cisterns and stormwater management ponds.
- Karst/Sensitive Environmental Feature SetbacksSetbackThe distance a building must be held back from a lot line.
Each Karst/Sensitive Environmental Feature within the LOD ... is subject to the setbacks specified in Table 5.05-1.
- Notice to property owners in deeds and plats
The following or similar language must be contained in all deeds of conveyance and on all subdivision plats and Site Plans applicable to land in the LOD: ...
- Structures prohibitedProhibitedNot allowed in the district at all, short of rezoning or a variance. in potential subsidence areas
Structures are prohibited in all areas where a Geophysical Study indicates that potential subsidence may occur that would cause property damage, physical injury, or harm to the public or future residents, unless there are no alternative locations within a given lot of record, and a subsequent Geotechnical Report indicates that such potential harm can be mitigated.
- Reduction of Karst/Sensitive Environmental Feature SetbacksSetbackThe distance a building must be held back from a lot line.50 pct
The Karst/Sensitive Environmental Feature Setback may be reduced by up to 50% if the Geophysical Study concludes that the risks of collapse and groundwater contamination are non-existent or insignificant for the proposed location and use.
- Exemption for structures or land disturbance of 600 sq ftsq ftSquare feet. An acre is 43,560 sq ft; a typical suburban lot is 7,000–10,000. or less600 sqftsq ftSquare feet. An acre is 43,560 sq ft; a typical suburban lot is 7,000–10,000.
Any land disturbing activities or structures involving the disturbance of 600 square feet or less of land, subject to the following: Land disturbing activities are not permitted within 20 feet of a Karst/Sensitive Environmental Feature; No structures, even if 600 square feet or less, are permitted within the Karst/Sensitive Environmental Feature Setback; Section 5.05.B.2.d does not apply to swimming pools, principal dwellings, and accessory dwellings, or to structures or land disturbing activities whose purpose is to change water flow; and Section 5.05.B.2.d does not apply to wells, except in cases involving the replacement of a dry well serving an existing inhabited structure.
- Stormwater management improvements not within Karst setbacksSetbackThe distance a building must be held back from a lot line. and lined with imperviousImpervious coverageThe share of a lot covered by anything water cannot soak through — roofs, drives, patios. materials
Stormwater management improvements constructed within the LOD must meet the following standards: Must not be located within Karst/Sensitive Environmental Feature Setbacks; Must provide a Geophysical Study; and Stormwater management ponds, sediment traps, and sediment basins must be lined with impervious materials in accordance with Chapter 5 of the FSM.
- Trail setbackSetbackThe distance a building must be held back from a lot line. from Karst features25 ft
Publicly accessible trails and other passive recreation facilities ... must be designed with permeable materials and setback a minimum of 25 feet from each Karst/Sensitive Environmental Feature.
From the ordinance
The purpose of the Limestone Overlay District is to preserve and protect the unique geologic characteristics and the groundwater quality in its limestone area.