Section 148-42 STEEP SLOPES.
Steep slopes, when developed, require more grading and land disturbance than development of flat to gently sloping topographical areas. Therefore, the purpose of this section is to establish protective regulations to:
1. Minimize soil disturbance on steep or critical slopes due to the potential for erosion problems;
2. Assist in the prevention of soil erosion from storm water runoff, protect downstream buildings and yards from water and soil intrusion, and protect the Town’s surface and groundwater resources from siltation and contamination;
3. Promote stable building sites that prevent soil erosion and are structurally sound so as to maintain slope stability;
4. Promote accessibility for fire and rescue apparatus;
5. Maintain the visual and environmental resources that are part of the character of Front Royal; and
6. Encourage innovative development in Front Royal by providing the flexibility necessary to produce environmentally sensitive subdivisions which direct building, parking and street locations to terrain more suitable to development while maximizing conservation of the original slopes, native cover, prominent land forms, rocky outcrops, natural open space, wildlife habitat and scenic resources.
All proposed subdivisions which result in the creation of an additional building lot or lots with the exception of boundary line adjustments, must submit a plan, in addition to any required subdivision development, street construction or erosion & sediment control plan, identifying predevelopment areas of steep slope. Clear cutting or grading for the purpose of altering predevelopment slopes shall not be permitted.
C. Establishment of Steep Slope Areas
The predevelopment slopes shall be computed by rise over run from naturally occurring contour lines based on topographic information showing two foot contour intervals and based on NAVD 88 vertical datum. The topographic data may be field run or from aerial photography, provided the information is current and the contouring method provides the precision expected for the contour interval used.
1. Identification of Steep Slope Areas. Steep slopes areas are classified into one of the following two categories:
a. All areas of slope between 15% and 25% which contain highly erodible, highly permeable or shrink-swell soils. Determination of soils which are highly erodible, highly permeable or shrink-swell shall be based on the USDA Soil Conservation Service Soil Survey of Warren County, Virginia, or based on soils analysis prepared by a geotechnical engineer or other appropriate licensed professional.
b. All areas of slope greater than 25%.
2. Minimum Size of Steep Slope Area. Steep slope standards do not apply to isolated steep slope areas that are less than 5,000 square feet in land area. For the purposes of this provision, the entire contiguous area of the steep slopes shall be included in the minimum size calculations, regardless of the number of individual lots or different land ownerships involved.
D. Creation of Slope Overlays
The plan identifying steep slopes and critical slopes must include overlays over the entire tract involved identifying by color coding the following:
1. All areas of slope between 15 to 25% which contain highly erodible, highly permeable or shrink-swell soils.
2. All areas of slope greater than 25%.
E. Plan Requirements
An overlot grading plan, prepared by a professional licensed by the State of Virginia to prepare such a plan, for the development, management, stabilization and preservation of steep slope areas shall be prepared in accordance with the detail requirements of Town Code Section 148 and upon submission of a report by a certified soil or geotechnical engineer, and/or other appropriate licensed professional, indicating if and how the steep slope may be safely developed.
final subdivision plat showing any
lot or portion of any lot located within a steep slope overlay area
contain a note stating that the property shown hereon is subject to the
provisions of Section 148-42, Steep Slopes, of the
F. Building Site Requirements
In addition to the requirements of the grading plan described herein, the plan shall include the following standards:
1. Site development shall be designed in a manner that requires a minimum amount of alteration to the steep slope.
2. Existing vegetation shall be preserved to the maximum extent possible.
3. No finished slopes are to be created with a final grade greater than 15% unless deemed feasible by a geotechnical report.
4. Residential driveway grades exceeding 10% are not recommended. Residential driveway grades greater than 10% shall be constructed in conformance with Virginia Department of Transportation’s (VDOT) standard CG-9 or other applicable entrance detail requirements. Commercial or industrial driveway grades shall be constructed in conformance with VDOT standard CG-11 or other applicable entrance detail requirements. All driveways shall have a nonerodable surface treatment, such as asphalt or concrete pavement. Side slopes for driveway cuts shall not exceed 25% (4:1) unless deemed feasible by a geotechnical report.
5. Use of retaining wall is encouraged to reduce the steepness of man-made slopes and to provide planting pockets conducive to vegetation and landscaping. All retaining walls shall require an engineered design with the exception of non-tiered retaining walls with level backfill and no surcharge loading with a height of 24 inches (2.0 feet) or less from the finished grade. Retaining walls shall not exceed 72 inches (6.0 feet) in height from the finished grade, however, the Town Council, at its discretion, may waive the maximum height requirement for retaining walls located within non-residentially zoned areas. This provision is not intended to preclude a structure’s foundation or basement wall or the creation of a walkout basement.
6. Landscaping and plantings shall be in accordance with Town Standards.
G. As-Built Plan Required
A post construction As-Built survey of the approved steep slope overlot grading plan shall be required prior to the issuance of an approved occupancy permit. The As-Built drawings shall clearly show any changes or variations from the approved design, and if deemed significant by the Director, may require any such change or variation be brought into compliance with the approved plan. The As-Built information shall be shown on the original plan and include the following:
1. Horizontal variations greater than 1.0 foot should be shown dimensionally or through plus stations. Horizontal variations greater than 5.0 feet should also show the graphic relocation of the object. Vertical elevation variations greater than 0.1 feet shall be provided for all shown design elevations.
2. All As-Built information shall be shown on the original plan either as blocked in or drawn in a different text style or font from that as shown on the original plan.
3. Each sheet of the plan shall contain the words “AS-BUILT” in bold text on or near the title block.
4. Date, plan legend, bar scale and north arrow.
5. Retaining walls. Indicate type and show elevations of the top of wall and the lowest adjacent finished grade.
6. Curb cut, driveway and material. Centerline grade of driveway with spot elevations.
7. Spot elevations of graded areas to determine grade of finished slope. Highlight all areas of finished slopes exceeding design grade by more than 1%.
8. Horizontal location with dimensions of all structures with dimensions including porches, decks, garages, etc. Show vertical elevations of first floor and basement floor.
9. Horizontal and vertical location of roof drains, foundation drains and other drainage outlets. Locations of utility services.
10. Location of required plantings.
11. The final as-built plan must be stamped by Licensed Land Surveyor or Professional Engineer and include certification that the As-Built plan is substantially in conformance with the original plan. If a geotechnical report is used, the appropriate licensed professional must certify that the As-Built is in conformance with the report.
Except as otherwise provided herein, no disturbance of steep slopes will be allowed except for the following activities which may be permitted by exemption from the Director of Planning & Zoning:
1. Utility service lines, walkways, steps, landings.
2. Emergency action to remediate an unstable slope which poses an imminent threat to health, safety or welfare of the public.
3. Normal landscape maintenance or routine arboreal activities, including small scale planting of ornamental flowers or shrubs, and/or the removal of diseased or damaged trees, and/or the removal of undesirable trees, provided revegetation is in conformance with Town Standards.
4. Disturbance for public roadway or street crossings, or other public purposes as determined by the Director of Planning.
5. Construction of approved landscaping berms, drainage ditches or swales, ponds and dams and other required storm drainage conveyance facilities.
Slope: The steepness, incline, gradient or grade of the natural incline of the ground expressed as a percentage based on computations of rise over run between existing contours.
Slope, Steep: (1) Areas of slope of the natural incline of between 15% to 25% which contain highly erodible, highly permeable or shrink-swell soils. (2) Areas of slope of the natural incline greater than 25%.
Grading Plan: A map or drawing, other than a plat, prepared by the appropriate licensed professional, showing existing and proposed topography, environmental controls, demolition and/or improvements to the property in accordance with the requirements of this ordinance and/or other applicable local, state or federal regulations.
As-Built Plan: A map or drawing, other than a plat, prepared by the appropriate licensed professional, showing existing post construction topography in comparison to the proposed site improvements shown on the approved site plan.
Overlot Grading Plan: See ‘Grading Plan’.
(Ord. No. 5-07 Amended (A-D) & Added (E-G) 2-26-07-Effective Upon Passage)
(Ord. No. 4-10 Amended Entire Section 4-26-10-Effective Upon Passage)