§ 5.5-9. Performance standards.
(a)
Purpose and intent. The performance standards establish the means to minimize erosion and sedimentation potential, reduce land application of nutrients and toxics, and maximize rainwater infiltration. Natural ground cover, especially woody vegetation, is most efficient in holding soil in place and preventing site erosion. Indigenous vegetation, with its adaptability to local conditions without the use of harmful fertilizers or pesticides, filters stormwater runoff. Keeping impervious cover to a minimum enhances rainwater infiltration and effectively reduces stormwater runoff potential.
The purpose and intent of these requirements is also to implement the following objectives: prevent a net increase in nonpoint source pollution from new development; achieve a ten (10) percent reduction in nonpoint source pollution from redevelopment; and achieve a forty (40) percent reduction in nonpoint source pollution from agricultural and silvicultural uses.
(b)
General performance standards.
(1)
Land disturbances shall be limited to the area necessary to provide for the proposed use or development.
a.
In accordance with an approved plan of development, the limits of clearing and/or grading shall be clearly shown on submitted plans and physically marked on the development site in accordance with (2)b below.
b.
Ingress and egress during construction shall be limited to one access point, unless otherwise approved by the director.
(2)
Indigenous vegetation shall be preserved to the maximum extent practicable consistent with the use or development proposed by an approved plan of development.
a.
Existing trees over eight (8) inches in diameter at breast height shall be preserved except in impervious areas. Diseased, dead, or dying trees, trees weakened by age, storm, fire, or other injury and shrubbery or noxious weeds may be removed subject to the approval by the director. The thinning of trees may be allowed pursuant to sound horticultural practices, subject to approval by the director.
b.
Prior to clearing or grading, suitable protective lines, such as survey tape or rope shall be established outside of the dripline of any tree or stand of trees to be preserved unless otherwise approved on the clearing plan. Protective lines shall remain so erected throughout all phases of construction. The storage of equipment, materials, debris, or fill shall not be allowed within the area protected by the lines.
(3)
Land development shall minimize impervious cover to promote infiltration of stormwater into the ground consistent with the proposed use or development permitted.
(4)
Any land disturbing activity exceeding two thousand five hundred (2,500) square feet, including construction of all single-family houses, shall comply with the requirements of the Erosion and Sediment Control Ordinance (Chapter 7.5).
(5)
All on-site sewage disposal systems not requiring a Virginia Pollutant Discharge Elimination System (VPDES) permit shall be pumped out at least once every five (5) years. Furthermore, in lieu of requiring proof of septic tank pump-out every five (5) years, the county may allow owners of on-site sewage treatment systems not requiring a VPDES to submit to county, documentation every five (5) years, certified by a sewage handler permitted by the Virginia Department of Health, that the septic system has been inspected, is functioning properly, and the tank does not need to have the solids pumped out.
(6)
For new construction, a reserve sewage disposal site with a capacity at least equal to that of the primary sewage disposal site shall be provided. This reserve sewage disposal site requirement shall not apply to any lot or parcel recorded prior to October 1, 1989, if the lot or parcel is not sufficient in capacity to accommodate a reserve sewage disposal site, as determined by the county's health department. Building shall be prohibited on the area of all sewage disposal sites until the structure is served by public sewer or an on-site sewage treatment system which operates under a permit issued by the state water control board.
(7)
For any development or redevelopment, stormwater runoff shall be controlled by the use of best management practices consistent with the water quality protection provisions of the Virginia Stormwater Management Regulations (4VAC 3-20-10 et seq.):
a.
For new development sites, the post-development nonpoint source pollution runoff load shall not exceed the pre-development load, based on average land cover conditions within the Chesapeake Bay Watershed (assumed 0.45 lbs. per acre per year);
b.
For redevelopment sites, the nonpoint source pollution load shall be reduced by at least ten (10) percent. The director may waive or modify this requirement for redevelopment sites that originally incorporated best management practices for stormwater runoff quality control, provided the following provisions are satisfied:
1.
In no case may the post-development nonpoint source pollution runoff load exceed the pre-development runoff load.
2.
Runoff pollution loads must have been calculated and the BMPs selected for the expressed purpose of controlling nonpoint source pollution.
3.
If BMPs are structural, evidence shall be provided that facilities are currently in good working order and performing at the design levels of service. The director may require a review of both the original structural design and maintenance plans to verify this provision. A new maintenance agreement may be required to ensure compliance with this chapter.
(8)
Prior to initiating grading or other on-site activities on any portion of a lot or parcel, all permits required by federal, state and county laws and regulations shall be obtained and evidence of such submitted to the director; and
(9)
Land upon which agricultural activities are being conducted, including but not limited to, crop production, pasture and dairy, and feedlot operations, or lands otherwise defined as agricultural land shall have a soil and water quality conservation assessment conducted that evaluates the effectiveness of existing practices pertaining to soil erosion and sediment control, nutrient management, and management of pesticides and, where necessary, results in a plan that outlines additional practices needed to ensure that water quality protection is being accomplished consistent with this chapter. Such a plan shall be subject to approval by the Tidewater Soil and Water Conservation District.
(c)
Buffer area requirements. To minimize the adverse effects of human activities on the other components of RPAs, state waters, and aquatic life, a 100-foot buffer area of vegetation that is effective in retarding runoff, preventing erosion, and filtering nonpoint source pollution from runoff shall be retained if present and established where it does not exist. A buffer area not less than one hundred (100) feet in width shall be located adjacent to and landward of other RPA components and along both sides of any water body with perennial flow. The full buffer area shall be designated as the landward component of the RPA. The 100-foot buffer area shall be deemed to achieve a seventy-five (75) percent reduction of sediments and forty (40) percent reduction of nutrients. All subdivision plats submitted for approval after the adoption of this chapter, shall clearly identify the boundaries of any RPA within the property. Such plat shall contain a statement that all existing vegetation within the RPA shall remain in its undisturbed natural state, except for vegetation weakened by age, storm, fire or other natural cause. Developers shall install flags identifying the landward limit of the RPA until completion of construction. Flags shall be installed and maintained in accordance with guidelines established by the director. The following additional performance criteria shall apply:
(1)
In order to maintain the functional value of the buffer area, indigenous vegetation may be removed subject to the approval by the director, only to provide for reasonable sight lines, access paths, general wood lot management, and BMPs, including those that prevent the upland erosion and concentrated flow of stormwater as follows:
a.
Trees may be pruned or removed as necessary to provide for sight lines and vistas, provided that where removed, they shall be replaced with other vegetation that is equally effective in retarding runoff, preventing erosion and filtering nonpoint source pollution from runoff. Any removal of existing vegetation shall require approval following review of the plan of development;
b.
Access paths shall be constructed and surfaced so as to effectively control erosion;
c.
Dead, diseased, or dying trees or shrubbery and noxious weeds may be removed subject to the approval of director; and thinning of trees may be allowed pursuant to sound horticultural practices as approved by the director; and
d.
For shoreline erosion control projects, trees and woody vegetation may be removed, necessary control techniques employed, and appropriate vegetation established to protect or stabilize the shoreline in accordance with the best available technical advice and applicable permit conditions or requirements.
(2)
When application of the buffer area would result in the loss of buildable area on a lot or parcel recorded prior to October 1, 1989, the administrator may permit encroachments into the buffer area in accordance with the following criteria:
a.
Encroachments into the buffer area shall be the minimum necessary to achieve a reasonable buildable area for a principal structure and necessary utilities;
b.
Where practicable, a vegetated area that will maximize water quality protection, mitigate the effects of the buffer encroachment, and is equal to the area of encroachment into the buffer area shall be established elsewhere on the lot or parcel; and
c.
The encroachment may not extend into the seaward fifty (50) feet of the buffer area.
(3)
On agricultural lands, the agricultural buffer area shall be managed to prevent concentrated flows of surface water from breaching the buffer area and appropriate measures may be taken to prevent noxious weeds from invading the buffer area. Agricultural activities may encroach as follows:
a.
Agricultural activities may encroach into the landward fifty (50) feet of the 100-foot wide buffer area when at least one (1) agricultural best management practice which, in the opinion of the local soil and water conservation district board, addresses the more predominant water quality issue on the adjacent land - erosion control or nutrient management - is being implemented on the adjacent land, provided that the combination of the undisturbed buffer area and the best management practice achieves water quality protection, pollutant removal, and water resource conservation at least the equivalent of the 100-foot wide buffer area. If nutrient management is identified as the predominant water quality issue, a nutrient management plan, including soil tests, must be developed consistent with the Virginia Nutrient Management Training and Certification Regulations (4 VAC 5-15 et seq.) administered by the Virginia Department of Conservation and Recreation.
b.
Agricultural activities may encroach within the landward seventy-five (75) feet of the 100-foot wide buffer area when agricultural best management practices which address erosion control, nutrient management, and pest chemical control, are being implemented on the adjacent land. The erosion control practices must prevent erosion from exceeding the soil loss tolerance level, referred to as "T", as defined in the "National Soil Survey Handbook" of November 1996 in the "Field Office Technical Guide" or the U.S. Department of Agriculture Natural Resource Conservation Service. A nutrients management plan, including soil tests, must be developed, consistent with the Virginia Nutrient Management Training and Certification Regulations (4 VAC 5-15 et seq.) administered by the Virginia Department of Conservation and Recreation. In conjunction with the remaining buffer area, this collection of best management practices shall be presumed to achieve water quality protection at least the equivalent of that provided by the 100-foot wide buffer area.
c.
The buffer area is not required for agricultural drainage ditches if the adjacent agricultural land has in place BMPs in accordance with a conservation plan approved by the tidewater soil and water conservation district.
d.
Where land uses such as agriculture or silviculture within the area of the buffer cease and the lands are proposed to be converted to other uses, the full 100-foot wide buffer shall be re-established. In re-establishing the buffer, management measures shall be undertaken to provide woody vegetation that assures the buffer functions as set forth in this chapter.
(Ord. of 12-4-2012)
(Ord. of 12-4-2012)