Site design, materials, and methods of construction or operation shall be designed to avoid erosion damage, sedimentation or uncontrolled surface runoff.
A.
The following requirements must be complied with whether a special permit is required or not.
(1)
Slopes of 10% or greater which result from grading, construction, or other land alteration shall be stabilized either through a structural retaining wall or cribbing, or through vegetative slope stabilization, comprising not less than four inches of topsoil planted densely with plants having shallow fibrous roots sufficient to retain the soil. The Building Inspector may require mulch or other temporary stabilization measures. Either a constructed surface or cover vegetation will be provided immediately following filling or stripping.
(2)
Placing more than 100 cubic yards of fill on any lot or raising ground level by three vertical feet or more within any lot shall require a permit from the Building Inspector. Reasonable care shall be taken to avoid harmful diversion of water affecting adjoining properties; that mature trees shall be reasonably protected; that no resultant slope shall exceed one foot vertical to two feet horizontal. Either a constructed surface or vegetation will be provided immediately following fillings or stripping.
B.
Special permit required. Each of the following shall require a special permit from the Zoning Board of Appeals:
(1)
Placing more than 200 cubic yards of fill per acre on any parcel.
(2)
Exposing more than two acres of bare earth through either removal or filling unless in conjunction with agricultural activity or in conjunction with road construction.
(3)
Construction or grading of more than 3,000 square feet of land where the average natural slope exceeds 25%.
C.
Application for special permit shall include a plan showing existing and proposed grades at key locations, vegetation (or other surface cover) and description of temporary or permanent impoundment basins or other methods proposed for controlling erosion, sedimentation, or other soil instability during and after construction. The Board of Appeals may require the applicant to submit a report from the USDA Natural Resources Conservation Service (NRCS) or soil loss calculation prepared by a soil scientist or engineer in cases of doubt as to adequacy of proposed measures. The Board may also require the furnishing of a performance bond or other security during the construction period. The Board of Appeals shall obtain a recommendation from the Conservation Commission. Such special permit shall be granted only if the Board determines that adequate provisions have been made for control of erosion, sedimentation, and runoff, both during and after construction; for avoidance of unsightly conditions; and for protection against other environmental degradation.