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HomeMy WebLinkAboutWPO201300005 Assessment - Environmental 2013-01-23 ,r < Soil Erosion Control Narrative and Computations KINGS GRANT DAMS /DRIVEWAY Albemarle County Charlottesville, Virginia January 18, 2013 Job No. 12-019-00 GLOECKNER ENGINEERING/SURVEYING, INC. Engineers, Surveyors &Land Planners 1980 Fox Run Lane Charlottesville, Virginia 22901 (434) 971-1591 PROJECT DESCRIPTION/LAND DISTURBED AREA This project consists of the construction of a driveway and 3 dams located on the property known as "Kings Grant."The property is south of State Route 676, one mile west of the Rivanna Reservoir Bridge crossing on the Ivy Creek portion. Land distured area is 4.53 acres. EXISTING SITE CONDITIONS The existing site is predominately wooded area where the driveway and dams are to be located. Trees are located on the upstream side of dam and will be removed. All effort will be made to keep trees except those trees and shrubs directed to be removed for adequate driveway, pond, and dam protection. The trees that are cut down in the dam/pond area will be replaced 3 for every one removed. ADJACENT PROPERTY The dams and driveway are bounded by woods on three sides and large residential property(large tracts) on all sides. OFF-SI FE ACTIVITIFS There will be no off-site activity. RUN-OFF CONSEQUENCES The construction of the driveway and dams will not cause an increase in run-off rates or cause flooding. Nor will the channels have degradation flow. The dam will provide run- off and detention that did not exist originally. Also, erosion control rip-rap will be used at all pipe discharge points and channels to reduce velocities and prevent erosion. (i.e. stabilize the banks of the streams). SOIL 14C- Chester Loam, 7 to 15 percent slopes This deep, strongly sloping, well drained soil is on narrow, convex ridgetops, the points of ridges, and narrow convex side slopes. Slopes are smooth and about 200 to 500 feet long. Areas of this soil commonly are long and winding. They range from 5 to about 40 acres. Typically,the surface layer of the Chester soil is dark brown loam about 7 inches thick. The subsoil is about 34 inches thick. It is mostly strong brown loam and yellowish red clay loam. The substratum to a depth of 60 inches is multicolored yellowish red, strong brown, white, and yellowish brown loam and sandy loam. 14D—Chester Loam, 15 to 25 percent Slopes This deep, moderately steep, well drained soil is on narrow, convex side slopes. Slopes are smooth and about 20 to 500 feet long. Areas of this soil commonly are long and winding. They range from 15 to about 40 acres. Typically,the surface layer of the Chester soil is dark brown loam about 7 inches thick. The subsoil is about 34 inches thick. It is mostly strong brown loam and yellowish red loam and clay loam. The substratum to a depth of 60 inches is multicolored yellowish red, strong brown, and yellowish brown loam and sandy loam. • 19B—Cullen Loam, 2 to 7 Percent Slopes This deep, gently sloping, well drained soil is on narrow to broad convex ridgetops. Areas of this soil commonly are irregularly rounded or oblong. They range from 3 to 15 or more acres. Typically,the surface layer of this soil is reddish brown loam about 8 inches thick. The subsoil is mostly red or dark red clay and clay loam about 52 inches thick. The substratum is mostly red, yellowish red, and yellowish brown loam. 36D—Hayesville Loam, 15 to 25 Percent Slopes This soil is deep , well drained, and moderately steep. It is on side slopes that border small drainage ways. Slopes are smooth and about 200 to 400 feet long. Areas of this soil are long and winding. They range from 5 to about 20 acres. Typically,the surface layer of this soil is brown and strong brown loam about 7 inches thisck. The subsoil is about 51 inches thick. It is mostly red clay and clay loam. The substratum to a depth of 83 inches or more is multicolored sandy clay loam derived from strongly weathered granite gneiss. 37D3—Hayesville Clay Loam, 15 to 25 Percent Slopes, Severely Eroded Tis soil is deep, well drained, and moderately steep. It is on side slopes that border small drainage ways. Slopes are smooth and about 200 to 400 feet long. Areas of this soil are long and winding. They range from 3 to about 20 acres. Typically,the surface layer of this soil is yellowish red clay loam about 4 inches thick. The subsoil is about 47 inches thick. It is mostly red clay and clay loam. The substratum to a depth of 79 inches or more is multicolored sandy clay loam derived from strongly weathered granite gneiss. CRITICAL EROSION AREAS The critical erosion areas found on this property are found primarily along the toes of darns running from east to west across the streams. This plan has been developed to minimize disturbance in these areas. They are generally adjacent to the stream and below the installation of the new dam center. STRUCTURAL PRACTICES 1. Temporary Construction Entrance - 3.02 Install a temporary construction entrance first. 2. Silt Fence—3.05 (With Wire Support) A temporary sediment barrier consisting of a filter fabric stretched across and attached to supporting points and entrenched. Silt fence is to be installed below the disturbed areas where erosion would occur in the form of sheet erosion as shown on the plan i.e., along the north and south toes of the dam. Also, silt fence will be installed across the existing emergency spillway and below the borrow area. 3. Culvert Inlet& Outlet Control—3.08 & 3.18 The inlet and outlet control items will be installed after the installation of the culvert 4. Dust Control—3.39 Dust control measures are to be employed throughout this project as necessary. Typically,temporary measures include,but are not limited to: irrigation, temporary seeding, and barriers. These measures will aid in the prevention of harmful airborne substances as well as the effects of wind erosion. VEGETATIVE PRACTICES 1. Temporary Seeding—3.31 Established of temporary vegetative cover on disturbed areas by seeding with appropriate rapidly growing plants on site that will not be brought to final grade for periods of 30 days to one year. German millet shall be used at the rate of 60 lb./acre, weeping lovegrass at 3 lb./acre and Korean lespedeze 20 lb./acre. 2. Dust Control 3.39 Dust control measures are to be employed throughout this when necessary. Typical temporary measures include, but are not limited to, irrigation, temporary seeding and barriers. The measures will aid in the prevention of harmful airborne substances as well as the effects of wind erosion. MANAGEMENT STRATEGIES 1. Construction should be sequenced so that grading operations can begin and end as quickly as possible. The first step after the erosion control items are in place is to clear and grub area within the limits of construction. 2. Erosion Control measures shall be installed as a first step prior to grading and • shall be seeded and mulched immediately following final installation or as soon as possible. 3. The job superintendent shall be responsible for the installation and maintenance of all erosion and sediment control practices. 4. A construction entrance will be necessary since the equipment will ingress and egress the site until the dam is complete. Contractor personnel will be arriving and departing at the residential driveway which will be under construction. Where construction vehicle access routes intersect paved public roads, provisions shall be made to minimize the transport of sediment by(vehicular)tracking onto the paved surface. Where sediment is transported onto a public road surface,the road shall be cleaned thoroughly at the end of each day as necessary. Sediment shall be removed from the roads by shoveling or sweeping and transported to a sediment control disposal area. Street washing if necessary shall be allowed only after sediment is removed in this manner. PERMANENT STABILIZATION All areas disturbed by construction will be stabilized with permanent seeding immediately following finish grading. Seeding will be done with Kentucky 31 Tall Fescue according to Std. & Spec. 3.32 of the 1992 Virginia Erosion and Sediment • Control Handbook. 5-20-10 fertilizer shall be applied at the rate of 1000 lb./acre and lime at 2 tons/acre. Permanently seeded areas shall be protected during establishment with straw mulch(2 tons/acres). MAINTENANCE In general, all erosion and sediment control measures will be checked daily and after each significant rainfall. The following items will be checked in particular: a. Should sediment basins and/or silt traps be required,they will be cleaned and maintained according to the Virginia Erosion& Sediment Control Handbook. b. All gravel outlets will be checked regularly for sediment buildup that will prevent drainage. If the gravel is clogged by sediment, it shall be removed and cleaned or replaced. c. All silt fence barriers will be checked regularly for undermining or deterioration of the fabric and repaired as required. Sediment shall be removed when the level of sediment deposition reaches half way to the top of the barrier. d. All seeded areas will be checked regularly to see that a good stand is maintained. Areas should be fertilized and reseeded as needed. MINIMUM STANDARDS MS-1 Stabilization of Denuded Areas and Soil Stockpiles Permanent or temporary soil stabilization must be applied to denuded areas within seven days after final grade is reached on any portion of the site. Temporary soil stabilization shall be applied within seven days to denuded areas that my not be at final grade but will remain dormant(undisturbed)for longer than 30 days. Permanent stabilization shall be applied to areas that are to be left dormant for more than one year. Soil stabilization refers to measures that protect soil from the erosive forces of raindrop impact and flowing water. Applicable practices include vegetative establishment, • mulching, and the early application of gravel base on areas to be paved. Soil stabilization measures should be selected to be appropriate for the time of year, site conditions and estimated duration of use. MS-4 Timing and Stabilization of Sediment Trapping Measures Sediment basins and traps, perimeter dikes, sediment barriers and other measures intended to trap sediment shall be constructed as a first step in any land-disturbing activity and shall be made functional before up-slope land disturbances take place. MS-5 Stabilization Measures Stabilization measures shall be applied to earthen structures such as dams, dikes and diversions immediately after installation. MS-8 Concentrated Runoff Concentrated runoff shall not flow down cut or fill slopes unless contained within an adequate temporary or permanent channel, flume or slope drain structure. (See Plan Sheet) MS-18 Disposition of Temporary Measures All temporary erosion and sediment control measures shall be removed within 30 days after final site stabilization or after the temporary measures are no longer needed, unless otherwise authorized by the local program administrator. Trapped sediment and the disturbed soil areas resulting from the disposition of temporary measures shall be permanently stabilized to prevent further erosion and sedimentation. 11.1 k v. � r1/4 4- N (n L co co N0) I--(<1 N k- U V) . 0 (0 w i • 0 (0 O N- O vi r w � CD D F- 0