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HomeMy WebLinkAboutSWA000064_Erosion Control Site Narrative 11-4-19_1/2/2020ROSLIN FARMS WEST SECTION 5 CUMBERLAND COUNTY, NC EROSION AND SEDIMENTATION CONTROL PLAN November 2019 PROJECT DESCRIPTION — SITE WORK ONLY This project consists of a 31-lot subdivision to be located off of SR 2243, Roslin Farms Road in Cumberland County. The work will include all the necessary construction needed to build the streets and to install the culvert storm drainage lines, and underground electrical lines required to serve a 31-lot development and the lot construction. It is anticipated that approximately 8.3 acres of this tract (includes streets, drainage system, etc) will be disturbed during construction. SITE DESCRIPTION The site contains mostly open fields with small areas of woods. The ground slopes associated with this site average from 0.20% to 3.00% grade for most of the site. Due to the extremely flat grades, the streets have been designed with side ditches so that the lots will drain away from the house pads to the side ditches. ADJACENT PROPERTY The site is bounded on the east by Roslin Farms Section 5 and on the north by rural, residential properties that are wooded. To the west lies Interstate 95, on the South by undeveloped property and on the south by a swamp through which Cold Camp Creek runs which is also the edge of the Robeson County Line. SOILS The main soils on the site consist of Ra, WaB, GoA and NoA soil types with small areas of AuA and Jt soil types. Ra — Rains Sandy Loam - This nearly level, poorly drained soil is on broad, smooth flats and in shallow depressions of uplands. The surface is very dark gray sandy loam 5 inches thick. The subsoil to a depth of 72 inches is gray sandy loam in the upper part and gray sandy clay loam in the lower part. Permeability is moderate. Reaction is very strongly acid or strongly acid throughout the soil. NoA — Norfolk Loamy Sand — 0 to 2 percent slopes. This well drained soil is on broad, smooth flats of uplands. The surface layer is brown loamy sand 8 inches thick. The subsurface layer is Page 2 of 4 Erosion and Sedimentation Control Plan Roslin Farms West Section 5 Subdivision light yellowish brown loamy sand 4 inches thick. The subsoil is sandy clay loam to a depth of 72 inches. It is yellowish brown in the upper part and mottled brownish yellow, red and pale brown in the lower part. Permeability is moderate, and available water capacity is medium. Reaction is strongly acid or medium acid throughout the soil. JT — Johnson Loam. This nearly level, very poorly drained soil is along major drainage ways. The surface layer is very dark gray loam 42 inches thick. The underlying material to a depth of 80 inches is dark grayish brown sandy loam in the upper part and light brownish gray sand in the lower part. Permeability is moderately rapid in the upper part of the soil and rapid in the lower part. Reaction is very strongly acid or strongly acid throughout. The soil is subject to frequent flooding. SITE DEVELOPMENT — CONSTRUCTION SCHEDULE 1. Obtain all necessary permits and plan approvals. 2. Preliminary staking and flagging for clearing. 3. Pre -construction conference before work begins. 4. Grade and install gravel construction entrance. 5. Install Temporary Skimmer Sediment Basins and Diversion Berms necessary for the site. 6. Start clearing and grubbing. 7. Install silt fences as clearing and grubbing continues. 8. Grading of streets and side ditches to subgrade. 9. Install storm drainage culvert 10. Install rock pipe inlet protection, complete storm construction. 11. Install rip -rap aprons at outlets. 12. Install underground electric. 13. Finish all rough grading, etc. 14. Finish sand -clay base and fine grade. 15. Pave project. 16. Fine grade areas that will receive grass, easements, etc. 17. Grass, mulch, and stabilize any disturbed areas. 18. Inspection and final acceptance letters. 19. Remove all temporary erosion control measures with concurrence of NCDENR Page 3 of 4 Erosion and Sedimentation Control Plan Roslin Farms West Section 5 Subdivision SITE DEVELOPMENT — PLANNED EROSION AND SEDIMENT CONTROL PRACTICES In order to control offsite sedimentation during construction, temporary structures including: gravel construction entrances, silt fencing, inlet protection, skimmer sediment basins, rock check dams, and temporary diversion berms will be installed. Gravel Construction Entrances (Site Development) A gravel construction entrance will be installed at location where construction traffic will enter and exit upon a paved street as shown on the Erosion Control Plan. Skimmer Sediment Basins (Site Development Skimmer Sediment basins will be installed as shown on the Erosion Control Plan. The basins are sighted in a location that will permit surface runoff during site development construction as well as street and lot drainage after the streets are built to be directed through the basin prior to it leaving the site. The basin will remain in place until all contributing drainage areas and lots are constructed and stabilized and will not be removed until NCDEQ approves removal. Sediment Basin w/ Riser & Skimmer (Site Development) Sediment Basins w/ Riser & Skimmer will be installed as shown on the Erosion Control Plan. The basins are situated in a location that will permit surface runoff to collect during site development construction as well as street and lot drainage after the streets are built to be directed through the basin prior to it leaving the site. The basin will remain in place until all contributing drainage areas and lots are constructed and stabilized and will not be removed until NCDEQ approves removal. Inlet Protection (Site Development) Inlet protection will be installed at each culvert to minimize the potential of sedimentation from entering into the storm drainage system. In most cases for site development work, rock pipe inlet protection will be used. Reinforced Silt Fence Outlet (Site Development) Reinforced Silt Fence Outlets will be installed along certain low-lying portions of the silt fencing surrounding the site in order to treat any storm runoff that might migrate towards the silt fencing and keep any excessive amounts of stormwater runoff from building up while treating smaller areas' runoff. Page 4 of 4 Erosion and Sedimentation Control Plan Roslin Farms West Section 5 Subdivision Silt Fencing (Site Development) Silt fencing will be installed as shown on the plan or as directed in the field to insure that sedimentation is not allowed to leave the construction limits. Grassing and Mulching All disturbed areas not to be immediately built on will be grassed and mulched with temporary ground cover. As site development work ends, all shoulders and easements will be grassed and mulched. All perimeter erosion control measures such as the diversion berms, sediment traps and sediment basin shall be grassed and mulched as soon after they are constructed as possible. All disturbed areas and particularly exposed slopes shall be seeded, fertilized and mulched within 21 working days. Following completion of any phase of grading. Permanent ground cover for all disturbed areas shall be established within 15 working days or no more than 90 calendar days. (Whichever is shorter following completion of construction or development) GENERAL MAINTENANCE PLAN Site Development Measures All erosion control measures shall be inspected after every runoff producing rainfall or at least once per week to insure that they are operating correctly. Any repairs or corrections required should be addressed as soon as possible after they have been identified. All implemented measures should be installed and maintained according to guidelines set forth in the NCDEQ Design Manual, this Erosion Control Narrative and the associated design drawings and details. Inspections of the erosion control measures should also be used to fulfill the NPDES requirement for the site. NOTE: 1. All measures will be inspected and necessary corrections made after runoff producing rainfalls, or at least once per week minimum. These inspections at a minimum will correspond with the requirements of the NPDES permit for the site. 2. Sediment basins, rock dams/berms, fences, traps, and inlet protection will be maintained as needed according to guidelines as set forth in the NCDEQ Erosion and Sedimentation Control Manual and according to the applicable construction details. 3. Seeding and mulching will be maintained to insure proper ground stabilizing cover. Any bare areas or areas that have no sufficiently germinated will be repaired as quickly as possible.