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HomeMy WebLinkAboutSD-24-08 - Supplemental - 0850 Hinesburg Road (14)Page 1 of 3 CONSTRUCTION AND EROSION CONTROL STANDARDS 16.01 Purpose 16.02 Applicability 16.03 Standards for Erosion Control during Construction 16.04 Excavation and Grading 16.01 Purpose It is the purpose of this Article to provide standards for proper erosion control and landscaping during and after land development activity in the City in order to prevent the adverse effects of erosion and runoff on the City’s residents, surface waters, and air quality. 16.02 Applicability Nothing in this Article shall be interpreted to supersede applicable permit conditions in an applicable permit issued by a superseding authority, including but not limited to those issued by the Vermont Department of Environmental Conservation or a permit issued by the Vermont Environmental Board pursuant to 24 VSA Chapter 151 (Act 250). Acknowledged. 16.03 Standards for Erosion Control during Construction A. Natural Cover. Land shall be subdivided and improved in reasonable conformity to existing topography in order to minimize grading, cut and fill, and to retain, insofar as possible, the natural contours, and to limit storm water runoff, and to conserve the natural cover and soil. The proposed project is comprised of smaller single family homes which enables the improvements to steps down the 10% gradient. After application for approval has been submitted to the Development Review Board, no topsoil, sand or gravel shall be removed from the subdivision for any other purpose than to meet construction needs of that particular subdivision or to meet any requirements of these regulations. No material is anticipated to be removed from the site. The only import will the granular materials required for the infrastructure constriction. B. Erosion and Sediment Control. (1) The smallest practical area of land should be exposed at any one time during development. When land is exposed during development, the exposure should be kept to the shortest practical period of time. Areas of disturbance must have temporary or permanent stabilization within 21 days of initial disturbance. This goal is iterated in supporting EPSC narrative and the temporary stabilization requirement is no less than 14 days after work on an area has ceased. (2) Land shall not be left exposed between October 15 and April 15. The project will be required to comply with the Winter EPSC management requirements which calls for daily stabilization during this time period. (3) Where necessary, temporary vegetation and/or mulching and structural measures shall be required by the Development Review Board to protect areas exposed during the development. This approach is included in the EPSC management narrative on Sheet C3.1. (4) Sediment basins (debris basins, desalting basins, or silt traps)shall be installed and maintained during development to remove sediment from run-off water and from land undergoing development. Page 2 of 3 One of the first requirements will be to shape the Gravel Wetland basin to be used initially as a sediment basin until the site has been stabilized. (5) The permanent final vegetation and structures shall be installed as soon as practical in the subdivision. Exposed soil must be seeded and mulched or covered with erosion control matting within 48 hours of final grading. This out outlined on Sheet C3.1 Section 4. (6) Adequate and permanent measures shall be taken at culvert outfalls to minimize or prevent erosion and disruption of drainageway areas. These BMPs are depicted on Sheet C3.0. Supporting details ar eon Sheets C3.1, C3.2 and C4.3 C. Site Restoration. After completion of construction, suitable grading or seeding shall be done to restore the condition of any disrupted portion of a site. This is outlined on Sheet C3.0 and the narrative on Sheet C3.1. 16.04 Excavation and Grading A. General. All excavating and filling required for construction of improvements shall be as specified within this Section. The entire area of work shall be brought to the required lines and grades by excavation or filling. Excavation material, if suitable, may be used in making embankments and in filling low areas. A minimum of four (4) inches of top soil shall be provided to cover overall finished slopes. This material shall be spread uniformly over all finished slopes. All streets shall be graded from property lines to property line to approved grade and cross section. Acknowledged. Topsoil placement is called out on Sheet C3.0. B. Fill. No stumps, wood, roots, sod, other fibrous materials or refuse shall be used as fill. Acknowledged. There won’t be much issue here as there are no tree to be removed. C. Embankments. Embankments shall be formed of suitable and acceptable excavated materials and brought to the required lines and grades. The materials for embankment shall be placed in successive horizontal layers not exceeding six (6) inches in depth extending across the entire fill area. They shall be spread by a bulldozer or other acceptable method, and shall be thoroughly compacted. Where embankments are made of rock, the rock shall be so deposited that all voids are filled with earth and in such a way that the compaction specified above may be secured. The earthwork requirements are outlined in the specifications on Sheet C5.0 D. Subgrade. Upon completion of filling and excavating, the subgrade shall be formed to the required grade and contour, and the entire surface again rolled as specified above. High spots shall be removed and low spots filled with the acceptable material and the process of leveling and rolling continued until no further depression results. The earthwork requirements are outlined in the specifications on Sheet C5.0 E. Side Slopes. Side slopes in embankments and on roadside drainage ditches shall descend one (1) foot vertically for at least each two (2) feet horizontally (2 on 1). Side slopes for this project are to be at least 3:1. Surplus material resulting from excavation of the road prism shall be used to flatten slopes of embankment so that they ascend one (1) foot vertically for at least (2) feet horizontally (2 on 1) Acknowledged. Side Page 3 of 3 slopes in excavation rock shall ascend six (6) feet vertically for at least each one (1) foot horizontally (1 on 6). There is no rock to be excavated on this project. Where rock cuts have a face higher than ten (10) feet vertically, a three (3) foot berm shall be provided at each ten (10) foot level above the grade at the edge of the pavement. Not applicable. Side slopes shall not be graded so as to extend beyond the limits of the street right-of-way onto land not part of the subdivision unless a suitable slope easement has been properly established and granted by the affected property owner. Acknowledged but not applicable.