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HomeMy WebLinkAboutWPO201300022 Assessment - Environmental 2013-03-27 EROSION AND SEDIMENT CONTROL NARRATIVE FOR Whittington Subdivision — Phase A March 15, 2011 Revised: August 10, 2011 Revised: November 3, 2011 Revised: July 22, 2013 LOCATION: Tax Map 89, Parcel 95 Tax Map 90, Parcels 3, 45,46,47,48 Samuel Miller District, Albemarle County, Virginia OWNER: Triumph Whittington, LLC 8230 Leesburg Pike, Suite 620 Vienna, VA 22182 PREPARED BY: Dominion Engineering and Design, LLC 172 South Pantops Drive Charlottesville, VA 22911 P: 434.979.8121 F: 434.979.1681 A. MINIMUM STANDARDS (MS): All applicable Virginia Erosion and Sediment Control Regulations and Minimum Standards shall be adhered to during all phases of construction. These include, but are not limited to the following: 1. STABLIZATION OF DENUDED AREAS: Permanent or temporary soil stabilization shall be applied to bare 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 may not be at final grade, but will remain dormant or undisturbed for longer than 30 days. Permanent stabilization shall be applied at areas that are to be left dormant for more than 1 year. 2. STABILIZATION OF SOIL STOCKPILES: During construction of the project, soil stockpiles shall be stabilized or protected with sediment trapping measures. The applicant is responsible for temporary protection and permanent stabilization of all soil stockpiles on site as well as soil intentionally transported from the project site. 3. PERMANENT VEGETATIVE COVER A permanent vegetative cover shall be established on denuded areas not otherwise permanently stabilized. Permanent vegetation shall not be considered established until a ground cover is achieve that, in the opinion of the county Inspector, is uniform and mature enough to survive to inhibit erosion. 4. TIMING & STABILIZATION OF SILT 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 upslope land disturbance takes place. 5. STABILIZATION OF EARTHEN STRUCTURES: Stabilization measures shall be applied to earthen structures such as dams, dikes and diversions immediately after installation. 6. SEDIMENT TRAPS AND BASINS: A sediment basin shall control surface runoff from disturbed areas that is comprised of flow from drainage areas greater than or equal to three acres. The sediment basin shall be designed and constructed to accommodate the anticipated sediment loading for the land disturbing activity. The outfall device or system device shall take into account the total drainage area flowing through the disturbed area to be served by the basin. 7. CUT AND FILL SLOPES: Cut and fill slopes shall be designed and constructed in a manner that will minimize erosion. Slopes that are found to be eroding excessively within one year of permanent stabilization shall be provided with additional slope stabilizing measures until the problem is corrected. 8. CONCENTRATED RUN-OFF DOWN CUT OR FILL SLOPES: Concentrated runoff shall not flow down cut or fill slopes unless contained within an adequate temporary or permanent channel, flume, or slope drain structure. 1 9. WATER SEEPS FROM A SLOPE FACE: Whenever water seeps from a slope face, adequate drainage or other protection shall be provided. 10. STORM SEWER INLET PROTECTION: All storm sewer inlets that are made operable during construction shall be protected so that sediment-laden water cannot enter the conveyance system without first being filtered or otherwise treated to remove sediment. 11. STABILIZATION OF OUTLETS: Before newly constructed stormwater conveyance channels are made operational, adequate outlet protection and any required temporary or permanent channel lining shall be installed in both the conveyance channel and receiving channel. 12. WORK IN LIVE WATERCOURSES: When work in a live watercourse is performed, precautions shall be taken to minimize encroachment, control sediment transport and stabilize the work area to the greatest extent possible during construction. Nonerodible material shall be used for the construction of causeways and cofferdams. Earthen fill may be used for these structures if armored by nonerodible cover materials. 13. CROSSING A LIVE WATERCOURSE: When a live watercourse must be crossed by construction vehicles more than twice in any six month period, a temporary stream crossing constructed of nonerodible materials shall be provided. 14. APPLICABLE REGULATIONS: All applicable federal, state and local regulations pertaining to working in or crossing live watercourses shall be met. 15. STABILIZATION OF BED AND BANKS The bed and banks of a watercourse shall be stabilized immediately after work in the watercourse is completed. 16. UNDERGROUND UTILITIES: Underground utilities shall be installed in accordance with the following standards in addition to other criteria: a. No more than 500 linear feet of trench may be opened at one time. b. Excavated material shall be placed on the uphill side of trenches c. Effluent for dewatering operations shall be filtered or passed through approved sediment trapping device, or both, and discharged in a manner that does not adversely affect flowing streams or offsite property. d. Material used for backfilling trenches shall be properly compacted in order to minimize erosion and promote stabilization. e. Restabilization shall be accomplished in accordance with these regulations. f. Applicable safety regulations shall be complied with. 17. CONSTRUCTION ACCESS ROUTES: Where construction vehicle access routes intersect paved public roads, provisions shall be made to minimize the transport of sediment by vehicular tracking onto paved surfaces. Where sediment is transported on to a public road surface, the road shall be cleaned thoroughly at the end of each day. Sediment shall be removed by shoveling or sweeping 2 and transported to a sediment control disposal area. Street washing shall be allowed only after sediment is removed in this manner. This provision shall apply to individual lots as well as to larger land disturbing activities. 18. TEMPORARY E&S CONTROL MEASURE REMOVAL: All temporary erosion and sediment control measures shall be removed within 30 days after final site stabilization or after temporary measures are no longer needed, unless otherwise authorized by the local program authority. Trapped sediment and the disturbed soil areas resulting from the disposition of temporary measures shall be permanently stabilized to prevent further erosion and sediment. 19. ADEQUACY OF RECEIVING CHANNELS: Properties and waterways downstream from the development site shall be protected from sediment deposition, erosion and damage, due to increases in volume, velocity and peak flow rates of stormwater runoff for the stated frequency storm of 24-hour duration. B1. PROJECT DESCRIPTION: The purpose of this project is to construct approximately 2150-LF of roadway and watermain (Roads A and E, and the Loop Road adjacent to road A). Also included is the construction of watermain approximately 3600-LF of sanitary sewer main. The total area to be disturbed by this project will be 23.7 acres. B2. EXISTING SITE CONDITIONS: The site is primarily wooded. There are three streams located on the property. The site is characterized by steep slopes, however, the disturbed area in Phase A is characterized by slopes ranging from 5% to 15%. B3. ADJACENT AREAS: The site is bounded to the Southwest by residential TMPs 90-39 to 90-48. To the Southeast by residential TMPs 90-3A and 90-3B. State Route 631, Old Lynchburg Road borders the entire southern side of the site. B4. SOIL DESCRIPTIONS: According to the Albemarle County Soils Survey conducted by the United States Department of Agriculture Soil Conservation Service, the primary soil types that may be disturbed during this scope of work have been identified as the following: 1. Albemarle very stony, fine sandy loam (3 D) - Permeability is moderate, surface runoff is rapid, and the hazard of erosion is severe. Hydrologic group B, K factor .37. 2. Catoctin very stony silt loam (13 D) - Permeability is moderately rapid, surface runoff is rapid, and the hazard of erosion is severe. Hydrologic group C, K factor .24. 3. Catoctin very stony silt loam (13 E) - Permeability is moderately rapid, surface runoff is very rapid, and the hazard of erosion is very severe. Hydrologic group C, K factor .32. 4. Culpeper fine sandy loam (21 B) - Permeability is moderate, surface runoff is medium, and the hazard of erosion is moderate. Hydrologic group C, K factor .37. 5. Culpeper fine sandy loam (21 C) - Permeability is moderate, surface runoff is rapid, and the hazard of erosion is severe. Hydrologic group C, K factor .37. 3 6. Culpeper fine sandy loam (21 D) - Permeability is moderate, surface runoff is rapid, and the hazard of erosion is moderate. Hydrologic group C, K factor .37. 7. Elioak loam (27 B)— Permeability is moderate, surface runoff is medium, and the hazard of erosion is moderate. Hydrologic group C, K factor .32. 8. Elioak loam (27 C)— Permeability is moderate, surface runoff is rapid, and the hazard of erosion is severe. Hydrologic group C, K factor .32. 9. Elioak loam (27 D)— Permeability is moderate, surface runoff is rapid, and the hazard of erosion is severe. Hydrologic group C, K factor .32. 10. Fauquier silt loam (29 B) — Permeability is moderate, surface runoff is medium, and the hazard of erosion is moderate. Hydrologic group C, K factor .32. 11. Fauquier silt loam (29 D) — Permeability is moderate, surface runoff is rapid, and the hazard of erosion is severe. Hydrologic group C, K factor .32. 12. Fauquier very stony, silt loam (31 D) — Permeability is moderate, surface runoff is rapid, and the hazard of erosion is severe. Hydrologic group C, K factor .28. 13. Fluvanna very stony silt loam (33 C) — Permeability is moderately slow, surface runoff is rapid, and the hazard of erosion is severe. Hydrologic group C, K factor .24. 14. Glenelg loam (34 C) — Permeability is moderate, surface runoff is rapid, and the hazard of erosion is severe. Hydrologic group B, K factor .32. 15. Glenelg loam (34 D) — Permeability is moderate, surface runoff is rapid, and the hazard of erosion is severe. Hydrologic group B, K factor .32. 16. Hazel loam (39 C) — Permeability is moderately rapid, surface runoff is rapid, and the hazard of erosion is severe. Hydrologic group C, K factor .32. 17. Hazel loam (39 D) — Permeability is moderately rapid, surface runoff is rapid, and the hazard of erosion is severe. Hydrologic group C, K factor .32. 18. Hazel loam (39 E) — Permeability is moderately rapid, surface runoff is very rapid, and the hazard of erosion is very severe. Hydrologic group C, K factor .32. 19. Hazel very stony loam (40 D) — Permeability is moderately rapid, surface runoff is rapid, and the hazard of erosion is severe. Hydrologic group C, K factor .24. 20. Hazel very stony loam (40 E) — Permeability is moderate surface runoff is very rapid, and the hazard of erosion is very severe. Hydrologic group C, K factor .24. 21. Meadowville loam (56 B) — Permeability is moderate to moderately rapid, surface runoff is medium, and the hazard of erosion is moderate. Hydrologic group B, K factor .37. 22. Orange very stony, silt loam (64 B) — Permeability is slow, surface runoff is medium, and the hazard of erosion is moderate. Hydrologic group D, K factor .24. 23. Watt channery silt loam (93 C) — Permeability is moderately rapid, surface runoff is rapid, and the hazard of erosion is severe. Hydrologic group D, K factor .32. 24. Watt channery silt loam (93 D) — Permeability is moderately rapid, surface runoff is rapid, and the hazard of erosion is severe. Hydrologic group D, K factor .32. B5. CRITICAL AREAS: The three streams and critical slopes are the critical areas of this site. B6. EROSION AND SEDIMENT CONTROL MEASURES: Unless otherwise indicated, all erosion and sediment control practices will be constructed and maintained according to the minimum standards and specifications as set forth in the Virginia Erosion and Sediment Control Handbook, latest edition. The minimum standards 4 • of the Virginia Erosion and Sediment Control Regulations shall be adhered to unless otherwise waived or approved by variance. SAFETY FENCE (SAF)— 3.01 Safety fence will be installed to prevent access to erosion control measures. Location and details are shown on the plans. TEMPORARY CONSTRUCTION ENTRANCE (CE) —3.02 An asphalt pad shall be constructed at the entrance of the project site to provide a means of removing sediment from the tires of construction vehicles leaving the work site. The Contractor shall remove any mud from the existing road surface by means of sweeping and shoveling, in the event the stone pad is not adequate in sediment removal. SILT FENCE (SF) —3.05 Silt fencing will be installed as a first step in construction activities. Location and details are shown on the plans. TEMPORARY DIVERSION DIKE (DD) — 3.09 A temporary diversion dike will be installed before site grading begins, for the purposes of diverting storm and sediment-laden runoff to the appropriate outlet or trapping facility. Location and details are shown on the plans. TEMPORARY SEDIMENT BASINS (SB) — 3.13 A temporary sediment basin will be installed before site grading begins, for the purpose of detaining sediment-laden runoff from disturbed areas. Location and details of the sediment traps are shown on the plans. OUTLET PROTECTION (OP) —3.18 Outlet protection will be installed according to Virginia Erosion and Sediment Control regulations. Location and details are shown on the plans. UTILITY STREAM CROSSING (USC) — 3.25 A strategy for crossing small waterways when in-stream utility construction is involved, for the purpose of helping to protect sediment from entering the stream from construction within approach areas. Location and details are shown on the plans. DUST CONTROL (DC)— 3.39 A variety of methods are available to prevent surface and air movement of dust from exposed soil surfaces and reduce the presence of airborne substances which may present health hazards, traffic safety problems or harm animal or plant life. B7. PERMANENT AND TEMPORARY STABILIZATION: SURFACE ROUGHENING — 3.29 Disturbed areas to be seeded and mulched shall be left in a roughened condition to help decrease runoff velocities and aid in the establishment of vegetation. TOPSOILING — 3.30 Topsoil may be stripped from the area to be graded and stockpiles for later use. All stockpiles which will be left dormant for more than 30 days shall be temporarily seeded. A 5 topsoil stockpile may be selected onsite by the developer and shall be temporarily protected with surrounding silt fencing. TEMPORARY SEEDING — 3.31 Temporary soil stabilization shall be applied within 7 days to denuded areas that may not be at final grade, but will remain dormant (undisturbed) for longer than 30 days and less than 1 year. This includes, but is not limited to areas such as soil stockpiles. Seeded areas shall be limed when necessary at a rate of 2 tons per acre, and fertilized at a rate of 450 lbs. per acre of 10-20-20 (10 lbs. per 1,000 square feet) or equivalent. A Temporary Seeding Schedule is attached for proper seed selection. PERMANENT SEEDING — 3.32 A perennial vegetative covering shall be established on disturbed areas within 7 days of being brought to final grade on areas not otherwise protected. Selection of the seed mixture shall depend on the time of year it is to be applied according to the Permanent Seed Schedule as shown on the drawing. Seeded areas shall be limed when necessary at a rate of 2 tons per acres, and fertilized at a rate of 1,000 lbs. per acre of 10-20-10 (10 lbs. per 1,000 square feet) or equivalent. • MULCHING — 3.35 All seeded areas shall be mulched with straw immediately following seeding operations. Straw mulch shall be applied at a rate of two tons per acre. SOIL STABILIZATION BLANKETS AND MATTING —3.36 Soil stabilization matting shall be applied in the conveyance areas of the designed diversions to help reduce velocities and aid in the establishment of vegetation. A detail showing the proper materials and installation is shown on the plan. B8. SOIL STOCKPILES AND BORROW AREAS A designated area for soil stockpiling and staging has been provided. B9. OFF-SITE AREAS: There will not be a need for borrow material. Excess material will be stored in a soil stock pile for future use. B10. STORM WATER MANAGEMENT: A dry pond and a wet pond are proposed to provide stormwater management for the site. Also, the wet pond, three bio-retention facilities are proposed. 811. MAINTENANCE SCHEDULE: A program of maintenance for the erosion and sediment controls specified in this narrative and shown on the plans are recommended as follows: 1. The Site Superintendent or his representative shall make a visual inspection of all erosion and sediment controls on a daily basis until the site is stabilized and especially after a heavy rainfall to assure that all controls are in place and that none have been damaged. Any damaged control shall be repaired prior to the end of each workday to include re-seeding if necessary. • 2. All silt trapping devices shall be cleaned out at 50 percent capacity and sediment shall be disposed of by spreading on site. 3. Gravel outlets shall be checked regularly for sediment buildup that may prevent • drainage. Controls shall be inspected and repaired after each rainfall and cleaned if sediment has accumulated to half of the device's original height. 6 • 4. All earthen structures such as diversion dikes and berms shall be checked daily during construction for breaching by equipment. Repairs shall be made immediately. 5. Silt fences shall be checked after each rainstorm to assure they have not fallen or become clogged with silt. All repairs shall be made immediately. 6. All seeded areas shall be inspected regularly to see that good stand is maintained. Areas will be re-fertilized and re-seeded as necessary. 7. After construction operations have ended and disturbed areas have been stabilized, all berms and sediment-trapping devices may be removed, after removal the ground shall be restored to its natural or proposed condition to include establishment of permanent vegetation. Removal of any control is contingent upon approval of the County Inspector. 7