GOURMET S DELIGHT MUSHROOMS EROSION & SEDIMENT CONTROL PLAN. Prepared by:

Transcription

1 GOURMET S DELIGHT MUSHROOMS EROSION & SEDIMENT CONTROL PLAN Prepared by: April 2016 Revised August 2016

2

3 Table of Contents NARRATIVE INTRODUCTION 1 PURPOSE 1 LOCATION MAP 2 EROSION CONTROL NOTES 3 SEQUENCE OF CONSTRUCTION 5 INFILTRATION BASIN SEQUENCE OF CONSTRUCTION 8 SEDIMENT BASIN CONVERSION TO WET POND 8 DRYWELL INSTALLATION 9 MAINTENANCE 10 GENERAL NOTES 11 TEMPORARY SEEDING 11 PERMANENT SEEDING 12 APPENDIX 13 STORMWATER PEAK FLOWS 15 SEDIMENT BASIN CALCULATIONS 21 ANTI-SEEP COLLAR CALCULATIONS 31 RIP-RAP CALCULATIONS 35 SOILS DATA TABLE 41 WORKSHEET #22 PLAN WRITER CREDENTIALS 45

4

5 GENERAL INFORMATION GOURMET S DELIGHT MUSHROOMS EROSION & SEDIMENT CONTROL PLAN This project consists of the construction of a new agricultural facility on an existing /- acre parcel. An existing dwelling and several outbuildings will remain and will continue to be utilized by the landowners. The tract is situated on the west side of Auburn Road in Franklin Township, Chester County (see Figure 1). No new streets are proposed as part of the project. The parcel will access Auburn Road via a new driveway entrance and will be served by on-lot water and sewer. The tract of land has moderately sloping terrain ranging from 3% to 25% that drains to Indian Run TSF/MF. The limit of disturbance consists of soils from the Glenelg Silt Loam soil series, with a B hydrologic subgroup designation. This site does not fall under Act 2 nor are there any known karst soils within the project. During the last five years, the fields have been used as a spray irrigation area for the compost/growing operation on the adjoining farm. The entire property has been farmed for the last fifty years. PURPOSE The purpose of this narrative is to describe methodologies used to prevent and manage accelerated soil erosion from the land development during construction of the agricultural facilities and appurtenances. A professional, experienced in erosion and sedimentation control design methods and techniques prepared this plan for the applicant. The Erosion & Sedimentation Control Plan and the Post Construction Stormwater Management Plan have been designed to be consistent with each other. EROSION AND SEDIMENT CONTROL NARRATIVE Accelerated erosion will be controlled by minimizing the amount of existing vegetative cover to be removed, providing temporary and permanent stabilization measures on disturbed areas as soon as possible, utilization of a rock construction entrance, silt soxx diversion, and through the use of erosion control blanket on slopes 3:1 or greater. In general, stripping of vegetation, regrading or other development is to be done in such a way that will minimize erosion. The primary control for capturing sediment from these areas will be a sediment basin and 24 silt soxx. The amount of disturbed area and the duration of exposure shall be kept to a practical minimum and the permanent vegetation and stormwater control systems will be installed as soon as possible to prevent erosion and therefore minimize the amount of sediment to be controlled. Compaction was minimized and protection to existing drainage features and existing vegetation was maximized through limited clearing and grading. The future stormwater infiltration area will be encircled with orange construction fencing to avoid compaction of the soils during site development. Most of the stormwater during construction will flow to the sediment basin which will be outfitted with a skimmer sized to dewater between 4-7 days therefore eliminating any potential for thermal impacts. 1

6 SITE LOCATION N Feet GOURMET'S DELIGHT FIGURE 1 LOCATION MAP 2

7 EROSION CONTROL NOTES: 1. All work shall be conducted in a manner to preserve all existing vegetation that is not required to be removed. 2. Work shall be scheduled and executed in a manner so that ground cover is removed and earthwork is exposed to erosion for the minimum time practical. 3. All off-site and on-site erosion and sediment damage shall be the responsibility of the contractor and shall be corrected immediately. 4. All erosion control work shall be done in accordance with the Erosion and Pollution Control Program Manual by Pennsylvania Dept. of Environmental Protection (PADEP), March The contractor shall be thoroughly familiar with the provisions of Appendix 64 "Erosion Control Rules and Regulations", Title 25, Part I, Subpart C, "Protection of Natural resources", and Article III "Water Resources", Chapter 102 Erosion Control. All are published by the Pennsylvania Department of Environmental Protection. 6. The operator shall remove from the site, recycle, or dispose of all building material and wastes in accordance with the Department's Solid Waste Management Regulations at 25 Pa. Code et seq., et seq., and et seq. The contractor shall not bury, dump, or discharge any building material wastes at the site. 7. A copy of the approved erosion and sediment control plan must be available at the project site at all times. The operator shall assure that an erosion and sediment control plan has been prepared, approved by the Chester County Conservation District (CCCD) and the Township, and is being implemented and maintained for all soil and/or rock spoil and borrow areas, regardless of their locations. 8. Before initiating any revision to the approved erosion and sediment control plan or revisions to other plans which may affect the effectiveness of the approved E&S control plan, the operator must receive approval of the revisions from CCCD and the Township. The operator shall assure that the approved erosion and sediment control plan is properly and completely implemented. Immediately upon discovering unforeseen circumstances posing the potential for accelerated erosion and/or sediment pollution, the operator shall implement appropriate best management practices to eliminate potential for accelerated erosion and/or sediment pollution. 9. Until the site is stabilized all erosion and sedimentation BMP's must be maintained properly. Maintenance must include inspections of all erosion and sedimentation BMP's after each runoff event and on a weekly basis. All site inspections will be documented in an inspection log kept for this purpose. The compliance actions and the date, time and name of the person conducting the inspection. The inspection log will be kept on site at all times and made available to CCCD or the Township upon request. All preventive and remedial maintenance work, including clean out, repair, replacement, regrading, reseeding, remulching and renetting, must be performed immediately. If erosion and sedimentation BMP's fail to perform as expected, replacement BMP's or modifications of those installed will be needed. Where BMP's are found to fail to alleviate erosion or sediment pollution the permittee or co-permittee shall include the following information: 3

8 a. The location and severity of the BMP's failure and any pollution events. b. All steps taken to, reduce, eliminate and prevent the recurrence of the non-compliance. c. The time frame to correct the non-compliance, including the exact dates when the activity will return to compliance. 10. Upon completion or temporary cessation of the earth disturbance activity that will exceed 4 days, or any stage there-of, the project site shall be immediately stabilized with the appropriate temporary or permanent stabilization. Hay or straw mulch shall be applied at a rate of 3.0 tons per acre. The mulch shall be anchored with a DEP approved binder, if conditions warrant. On steep slopes, netting shall be used to anchor mulch in place. Slope steepness, slope length, soil erodiblity and cut of fill conditions shall be considered in determining the need for netting or other mulch tacking methods. 11. All topsoil and earth stockpiles shall be placed in designated areas as shown on the plan and they shall be graded to minimize erosion. The maximum height for topsoil stockpiles shall be 35 feet and the maximum slope shall be 2:1. No topsoil, earth or other erodible material shall be placed within 25 feet of any inlet or drainage ditch, at any time. Upon completion or temporary cessation of the earth disturbance activity, windward slopes of stockpiles shall be graded to a 2:1 slope and shall be stabilized as outlined in Note #10 above. After construction is complete, any remaining stockpile material shall be graded onto the site and stabilized or hauled off site. 12. Erosion and sedimentation controls must be constructed, stabilized and functional before site disturbance within the tributary areas of those controls. 13. Crushed stone construction entrances shall be maintained in place until removal is necessary for final grading of the driveway subgrade. A stockpile of rock material will be maintained on the site to maintain the thickness of the construction entrance as shown on the plans. At the end of each construction day, all sediment deposited onto public roadways will be removed and returned to the construction site. Under no circumstances shall the sediment be washed, shoveled, or swept into any roadside ditch, stormsewer, or surface water. 14. If cut/fill doesn t balance, then the cut/fill shall be stockpiled/excavated in the locations designated on the plan. 15. The contractor is responsible for ensuring that any material brought on-site is clean fill. Form FP-001 must be retained by the property owner for any fill material affected by a spill or release of a regulated substance but qualifying as clean fill due to analytical testing. 16. Clearing and grubbing is to be limited to the areas that must be disturbed to accommodate proposed facilities. 17. When conditions warrant, the Contractor shall control excessive dust generated by construction activities on the site. 18. Site conditions may dictate that during construction, additional silt soxx and/or other methods of sediment control may be required. The Township, Chester County Conservation District (CCCD) or PADEP may, therefore, direct the installation of additional means of control to prevent the discharge of sediment from the site. 19. Silt soxx must be installed at level grade. Both ends of each fence section must extend at least 8 feet up slope at 45 degrees to the main fence alignment 20. Silt soxx sediment barriers shown on the plan should be repaired, cleaned or replaced if necessary. Any fence section that has been undermined or topped must be immediately replaced with a rock filter outlet. 21. Sediment must be removed when accumulations reach 1/2 the height of the silt soxx. 4

9 22. All slopes 3:1 or steeper and all areas within 50 feet of a surface water (100 feet for HQ/EV waters) must be stabilized with erosion control blanket. 23. All pumping of sediment laden water shall be through a sediment control BMP, such as a pumped water filter bag discharging over non-disturbed areas. 24. Seeps or springs encountered during construction shall be handled in accordance with the standard and specification for subsurface drain or other approved method. 25. Advanced clearing and grubbing operations for utility line excavation shall be limited to two times the length of pipe installation that can be completed in one day. 26. All excavation for utility line installation shall be limited to the amount that can be excavated, installed, backfilled, and stabilized within one working day. All excavated material shall be deposited on the upslope side of the trench. 27. Any water that accumulates in the open utility trench shall be completely removed by pumping through a filtration device before pipe placement and/or backfilling begins. 28. The contractor shall inspect, clean, and/or repair all erosion control facilities weekly or after each rain. The contractor shall remove all accumulated sediment as required and place on site in non-erodible areas and permanently stabilize these areas by seeding in accordance with the permanent seeding specifications. 29. Infiltration systems shall not be used for sediment and erosion control. Sediment laden runoff or runoff from sediment traps shall not be directed into infiltration structures or over future infiltration structures. 30. An Area shall be considered to have achieved final stabilization when it has a minimum uniform 70% perennial vegetative cover or other permanent non-vegetative cover with a density sufficient to resist accelerated surface erosion and subsurface characteristics sufficient to resist sliding and other movements. Immediately after earth disturbance activities cease, the operator shall stabilize any areas disturbed by the activities. During nongerminating periods, mulch must be applied at the specified rates. Disturbed areas which are not a finished grade and which will be redisturbed within 1 year must be stabilized in accordance with the temporary vegetative stabilization specifications. Disturbed areas which are at finished grade or which will not be redisturbed within 1 year must be stabilized in accordance with the permanent vegetative stabilization specifications. 31. After final site stabilization has been achieved, temporary erosion and sediment BMPs must be removed. Areas disturbed during removal of the BMPs must be stabilized immediately. 32. The Contractor shall maintain all areas where erosion is apparent for one year from the date of completion. Construction Sequence: All earth disturbance activities shall proceed in accordance with the following sequence. Each stage shall be completed before any following stage is initiated. Clearing and grubbing shall be limited only to those areas described in each stage. 1. At least 7 days before starting any earth disturbance activities, the operator shall invite all contractors involved in those activities, the landowner, all appropriate Township officials, CCCD, and the erosion and sedimentation control plan preparer to an on-site preconstruction meeting. In addition, at least 3 days before starting any earth disturbance activities, all contractors involved shall notify the Pennsylvania One Call System Inc. at 1-5

10 for buried utilities location. 2. Delineate all Limits of Disturbance with visible flagging or ribbon and encircle all existing and proposed sewage system components with orange construction fence. 3. Install rock construction entrance off Auburn Road per detail. 4. Install all 24 silt soxx as shown on the E & S Control Plan. 5. Stake out the sediment basin, forebay, and infiltration basin and begin stripping topsoil. Soil stockpiles shall be encircled with 18 silt fence and stabilized immediately with straw mulch. 6. Excavate the above facilities to rough grade elevation in conjunction with the installation of Retaining Wall #1 upslope of the basins. The infiltration basin shall be kept 1.0' higher than the permanent design elevation and encircled with orange construction fencing as soon as is feasible to keep further construction equipment from entering the footprint of the facility. Extra care should be taken to restrict construction equipment within 50 of the wetlands and streams. 7. The Conservation District shall be notified at least 24 hours prior to the installation of the riser and outlet pipe in the sediment basin. 8. Underdrains shall be provided in areas deemed necessary by the Municipal Engineer. 9. Install the weir between the forebay and the sediment basin (wet pond) but do not install the weir between the forebay and the infiltration basin. 10. EW-1 and the 42 pipes connecting to Inlet I-1. The rip-rap apron shall also be installed at this time. 11. Sediment basin, forebay, and infiltration basin shall be seeded per the permanent seeding specification and all slopes 3:1 or greater shall be stabilized with NAG S-75 matting or approved equal. 12. Install the silt soxx diversion above the infiltration basin diverting site runoff to the forebay. 13. Excavate for and install the proposed entrance driveway. Only excavate the amount of area that can be stabilized with stone within the same working day. 14. Begin installing storm sewer system as driveway construction progresses. 15. Once driveway has been installed to the main building site, continue driveway installation in a northernly direction connecting to the existing driveway on the property located in London Grove Township. 16. Install the stormsewer run beginning at Inlet I-29 and ending at EW-2, including the rip-rap apron and HW-1 diverting clean water around the construction site. Encircle inlets draining to EW-2 with 12 silt soxx per plan detail. 17. Fine grade, compact subgrade and install rolled curb from entrance to junction with main building site 18. Install 2A stone to finished grade, place binder course of paving on top of the stone. Install temporary inlet diversion (see detail) to divert driveway runoff into inlets. 19. Stake out the building sites and the remainder of the access driveways. 20. Strip topsoil and stockpile in areas designated on the plan. Soil stockpiles shall be encircled with 18 silt fence and stabilized immediately with straw mulch. 21. Excavate the building pads and parking lots to rough grade elevation. Excess subsoil that will not be used during the final grading process shall be hauled off site to an approved location. The landowner must exercise due diligence in maintaining any soil hauled off site is clean fill. In conformance with due diligence findings, asphalt and stone will be disposed of at an approved recycling facility. All subsoil removed from the site will be clean fill material. If any discrepancies are noted during excavation, the Project Engineer will be contacted to establish the proper course of action for the disposal of the non-clean fill. 6

11 22. While padding out the building site, ensure the building and parking lot areas drain towards the forebay/sediment basin. 23. Retaining Wall #2 shall be installed at this time per plan detail. 24. Remove the section of driveway leading to the existing dwelling, install Retaining Wall #3, and install the new section of driveway providing access from the remaining driveway to the dwelling. 25. Install both the northern (Inlets I-1 to I-7) and southern (Inlets I-1 to I-25) storm sewer systems, connecting to the forebay. Install roof downspout collection pipe connections per building plans. 26. Excavate for and install any utilities to the right of way. 27. Install the remainder of the rolled curbing per plan locations. 28. Stone the remaining access driveways and place binder course. Install temporary inlet diversion (see detail) to divert driveway runoff into inlets. 29. Once the driveways have been paved, building construction may commence. 30. The concrete waste lagoon may also be installed once the driveways have been stabilized with stone. Install the dirty water piping system to connect to the tank. The dirty water piping system, concrete waste lagoon, and dip pit shall all be installed per NRCS specifications. 31. As construction progresses, maintain sheet flow of surface runoff toward the sediment basin and installed silt soxx. 32. Since the Phase 1 and Phase 2/3 composting buildings will be built in stages, the following components shall be installed for each portion of building as appropriate: a. Install the wharf water collection system and dipping pit, connecting to the previously installed waste transfer pipe. b. Install the wharf and building portions within each building construction stage. c. Connect downspouts to the downspout collection pipe. 33. Respread topsoil and fine grade all areas surrounding the buildings. Areas disturbed shall be immediately stabilized per the permanent seeding specifications. 34. Critical Stage: When the area tributary to the drywell is determined to be uniformly stabilized (70% vegetative cover) based on a site inspection by the CCCD and the Township, the drywell and all correlating piping shall be installed. 35. Critical Stage: When the area tributary to the Sediment Basin is determined to be uniformly stabilized (70% vegetative cover) based on a site inspection by the CCCD and the Township, the basin shall be converted to its permanent wet pond capacity. Immediately prior to conversion, the storm sewer systems draining to the forebay shall be flushed to remove any sediment that may have accumulated in the piping and/or inlets during the construction process. See separate detailed sequence for conversion of the sediment basin to the wet pond below. 36. Critical Stage: When the area tributary to the infiltration basin is determined to be uniformly stabilized (70% vegetative cover) based on a site inspection by the CCCD and the Township, the last foot may be dug out of the basin, the weir may be installed between the forebay and the infiltration basin, and all rip-rap aprons may be installed. The basin shall be excavated approximately one foot lower than the design finish elevation and soils replaced with amended soils. Amended soils shall be comprised of two parts in-situ topsoil, one part mushroom compost, and one part sharp washed sand. Any equipment used within the basin should be light track equipment. See separate detailed sequence for the basin installation below. 37. Critical Stage: Install the filter area and landscape restoration areas. Filter area shall be seeded per the permanent seeding specifications and immediately stabilized with NAG S-75 matting. The Landscape restoration area shall be installed per the plan details. 7

12 38. Prior to the removal of any E&S control facility or the conversion of temporary E&S controls to permanent SW controls the CCCD and the Township must inspect the facility and approve the removal or conversion. 39. The permittee shall complete and submit a Notice of Termination (NOT) to CCCD upon completion and stabilization of project. CRITICAL STAGE: Infiltration Basin Installation: 1. The design professional engineer, or designee, shall be present during the following stages of construction: bottom of basin excavation, rough grading, weir installation, and during final grading/seeding/ mulching. 2. If unfavorable conditions are encountered during construction (i.e. - groundwater, bedrock, etc), excavation shall halt immediately. The design engineer shall be contacted to either re-locate or redesign the facility. 3. Strip the topsoil and stockpile in areas designated on the plan. 4. The basin shall be excavated approximately one foot lower than the design finish elevation and replaced with amended soils. Amended soils shall be comprised of two parts in-situ topsoil, one part mushroom compost, and one part sharp washed sand. 5. Compact the berm embankment to 95% modified proctor density. No organic material shall be used in the berm construction. The bottom of the berm shall not be compacted. 6. Follow the permanent seeding specifications for all areas disturbed by the installation of the berm/basin. 7. All slopes 3:1 or greater shall be stabilized with NAG S75 (or approved equal) at time of seeding. 8. The silt soxx down-slope of the basin shall remain in place until all contributory drainage is considered uniformly stabilized (70% vegetative cover). 9. When the area tributary to the infiltration basin is determined to be uniformly stabilized (70% vegetative cover) based on a site inspection by the CCCD and the Township, two feet shall be dug out of the bottom and amended soils placed per plan detail. 10. The permittee, shall provide engineering construction oversight for the proposed stormwater BMPs. Additional soil testing may be required prior to the installation of infiltration BMPs to ensure proper location and function. A licensed professional, engineer knowledgeable in the design and construction of stormwater BMPs, preferably the design engineer, shall conduct the oversight. Critical Stage - Sediment Basin Conversion to Permanent Wet Pond: 1. When the area tributary to the basin is determined to be uniformly stabilized (70% vegetative cover) based on a site inspection by the CCCD and the Township, the basin shall be converted to a permanent stormwater facility per plan specifications. 2. The design professional engineer, or designee, shall be present during the following stages of construction: bottom of basin excavation, riser modification, and during final grading. 3. If unfavorable conditions are encountered during construction (i.e. groundwater, bedrock, etc), excavation shall halt immediately. The design engineer shall be contacted to either relocate or re-design the facility. 4. Remove Faircloth skimmer from riser structure. 5. Modify existing Type M inlet to permanent stormwater outlet per plan detail. 6. Add/remove extender rings to the Type M inlet to achieve desired permanent rim elevation. If 8

13 this cannot be achieved through adding/removing rings, the Type M inlet must be replaced with one of proper dimensions as per plan detail. 7. Remove the super silt fence baffles. 8. Collect 6 randomly spaced soil samples for analysis to see if any soil amendments are needed to create and impermeable bottom. 9. If needed, add soil amendments per manufacturer s recommendations. 10. Stabilize all areas disturbed during the basin conversion process according to the permanent seeding specification. 11. The silt soxx down-slope of the basin shall remain in place until all contributory drainage is considered uniformly stabilized (70% vegetative cover). 12. The permittee shall provide engineering construction oversight for the proposed stormwater BMPs. Additional soil testing may be required prior to the installation of infiltration BMPs to ensure proper location and function. A licensed professional engineer knowledgeable in the design and construction of stormwater BMPs, preferably the design engineer, shall conduct the oversight. Critical Stage - Drywell Installation: 1. The drywell may not receive any stormwater until the contributory drainage area is uniformly stabilized (70% perennial vegetative cover or other permanent non-vegetative cover with a density sufficient to resist accelerated surface erosion and subsurface characteristics sufficient to resist sliding, and other movements) based on a site inspection by CCCD and the Township. 2. The design professional engineer, or designee, shall be present during the following stages of construction: bottom of bed excavation, fabric and stone placement, pipe installation, and during final grading. 3. Excavate the drywell to the design dimensions. Excavated materials shall be placed away from the excavated sides to enhance wall stability. Large tree roots shall be trimmed flush with the sides in order to prevent fabric puncturing or tearing during subsequent installation procedures. The bottom and sidewalls of the infiltration bed shall be roughened where sheared and sealed by heavy equipment. The facility shall only be constructed on undisturbed or uncompacted subgrade. Any equipment used shall be light track machines that will not compact the bottom of the seepage bed (maximum 4 PSI ground pressure). 4. If unfavorable conditions present (i.e. bedrock, groundwater, etc.), construction shall immediately cease and the design engineer be contacted in order to either re-locate or re-design the system. 5. The non-woven geotextile roll shall be cut to proper width prior to installation. The cut width must include sufficient material to provide a 12-inch minimum overlap for all joints. Stones or other anchoring objects should be placed on the fabric at the edge of the bed to keep the lined bed open during windy periods. 6. Drainage aggregate shall be placed in lifts and compacted using plate compactors. As a rule of thumb, a maximum loose lift thickness of 12 inches is recommended. Only uniformly graded, clean washed aggregate shall be used within the facility. 7. Install the perforated distribution pipes per the infiltration bed detail. 8. Following aggregate placement, the fabric previously weighted by stones should be folded over the aggregate to form a 12-inch minimum longitudinal overlap. The desired fill soil or parking lot subgrade/stone should be placed over the lap at sufficient interval to maintain the lap during 9

14 subsequent backfilling. 9. Installation of the stone to be checked by the design or site engineer prior to installation into the drywell to ensure that it is clean washed stone. 10. Care shall be exercised to prevent natural or fill soils from intermixing with the drainage aggregate. All contaminated aggregate shall be removed and replaced with uncontaminated aggregate. 11. Voids can be created between the fabrics and excavation sides and should be avoided. Removing boulders or other obstacles from the bed walls is one source of such voids. Natural soils should be placed in these voids at the most convenient time during construction to ensure fabric conformity to the excavation sides. This remedial process will avoid soil piping, fabric clogging, and possible surface subsidence. 12. Vertical drywell walls may be difficult to maintain in areas where the soil moisture is high or where soft cohesive or cohesionless soils predominate. These conditions may require laying back of the side slope to maintain stability. Trapezoidal rather than rectangular cross sections may result. 13. The permittee, shall provide engineering construction oversight for the proposed stormwater BMPs. Additional soil testing may be required prior to the installation of infiltration BMPs to ensure proper location and function. A licensed professional, engineer knowledgeable in the design and construction of stormwater BMPs, preferably the design engineer, shall conduct the oversight. MAINTENANCE PROGRAM: The following maintenance procedures shall apply: 1. All erosion and sedimentation control devices shall be checked every week and after every storm event. Inspections and any repairs shall be recorded on DEP form 3150-FM-BWEW0083 (dated 2/2012), kept onsite, and made available to CCCD, DEP, or the township upon request. 2. Should unforeseen erosive conditions develop during construction, the contractor shall take immediate action within 24 hours to remedy such conditions and to prevent damage to adjacent properties by an increase in run-off and/or sediment displacement. 3. Stockpiles of wood chips, hay/straw bales, crushed stone and other mulches and materials shall be held in readiness to deal immediately with emergency problems and conditions. 4. All topsoil storage areas shall be placed in an area not subject to concentrated run-off. The down slope side shall be protected by temporary silt fence and seeding. 5. Seeded areas that have washed away shall be filled and graded as necessary, reseeded and mulched. 6. Sediment must be removed from the silt soxx sediment barriers where accumulations reach one half of the above ground height of the barrier. Sediment cleaned from the silt soxx shall be graded on site and stabilized. Any silt soxx that has been undermined or over topped shall be replaced with stone filter outlets immediately. 7. Trash removed from the control devices shall be disposed of in any approved disposal area. 8. Any seeded or sodded areas that have become stripped of vegetation shall be re-established with appropriate stabilization materials. This procedure shall be repeated after every sizable storm until no more signs of erosion are evident. 9. The crushed stone construction entrance shall be maintained in place until removal is necessary 10

15 for final grading of the driveway subgrade. A stockpile of rock material shall be kept on the site to maintain the thickness of the construction entrance as shown on the plans. At the end of each construction day, all sediment deposited on public roadways will be removed and returned to the construction site. 10. Filter bags shall be inspected daily. If any problem is detected, pumping shall cease immediately and not resume until the problem is corrected. Bags shall be switched out when sediment capacity has been reached. 11. At the end of each working day, any and all sediment tracked onto, or conveyed by other means, onto a public roadway, will be removed and redeposited onto the construction site. Removal can be completed through use of either machinery or by hand tools, but under no circumstances shall be washed off the road by use of water. 12. Concrete washout areas shall be deactivated when they reach 75% capacity. The impervious plastic liners shall be replaced at each clean-out. GENERAL NOTES: 1. Completeness and accuracy of location and depth of underground utilities or structures cannot be guaranteed. Location and depth of all underground utilities and facilities must be verified prior to any earth moving activities as per Act 187 of Topographic data and contours are based on a site survey by Crossan-Raimato Surveyors; New London Twp, PA Soil types are shown according to Sheet No. 71 of the Soils Survey for Chester and Delaware Counties. 4. Stream/watershed classification: Indian Run TSF/MF. 5. Total Disturbed Area: 16.9 Acres 6. The project is anticipated to begin excavation immediately following the receipt of final plan approval. TEMPORARY SEEDING SPECIFICATIONS: Where it is not possible to permanently stabilize a disturbed area upon completion or temporary cessation of the earth disturbance activity, temporary seeding shall be done using the following seeding specifications: SEED: Seed Mixture #1 in Table Substitutions may be made with approval from CCCD and the Township. FERTILIZER: Standard Quality LIME: Agricultural Limestone - 1 ton/acre 85% minimum of carbonates MULCH: Straw or Hay - 3 tons/acre PERMANENT SEEDING SPECIFICATIONS: The specifications below are general in nature and acceptable for most soil types. It is still recommended to obtain soil samples from the site and test them at a qualified laboratory to 11

16 determine the most suitable species and application rates for the seed, lime and fertilizer in accordance with Penn State Erosion Control and Conservation Planting in Non-Cropland. SEED: Seed Mixture #2 in Table Substitutions may be made with approval from CCCD and the Township. FERTILIZER: Standard Quality LIME: Agricultural Limestone - 6 ton/acre 85% minimum of carbonates MULCH: Straw or Hay - 3 tons/acre SOD: Where specified on the plans or may replace any area that calls for seeding/mulching. See PennDOT Publication 408, Section 809 for installation specifications. Permanent seeding shall only occur during the dates listed above. If areas are prepared for seeding at other times, then the prepared seedbed shall be heavily mulched with clean, unrotted small grain straw or salt hay at a rate of 3 tons per acre. The mulch shall remain in place until seeding dates are appropriate. The mulch shall be removed; the area shall be dressed, seeded and remulched as described above. Areas which are to be top-soiled shall be scarified to a minimum depth of 3-5 inches (6-12 in compacted soils) prior to placement of topsoil. Areas to be vegetated shall have a minimum 4 inches of topsoil in place prior to seeding and mulching. The bottom of the infiltration basin shall receive approximately 1.0 of amended soils. These amended soils shall be comprised of two parts in-situ topsoil, one part mushroom compost, and one part sharp washed sand. 12

17 APPENDIX 13

18 This page intentionally left blank. 14

19 STORMWATER PEAK CALCULATIONS 15

20 This page intentionally left blank. 16

21 Hydrograph Return Period Recap Hydraflow Hydrographs by Intelisolve v9.02 Hyd. Hydrograph Inflow Peak Outflow (cfs) Hydrograph No. type Hyd(s) description (origin) 1-Yr 2-Yr 3-Yr 5-Yr 10-Yr 25-Yr 50-Yr 100-Yr 1 SCS Runoff DA #1 - Existing 2 SCS Runoff DA #1 - Proposed Uncontrolled 3 SCS Runoff DA #1 Controlled Forebay (Non-LD) 4 SCS Runoff DA #1 - Controlled Forebay (w/in LD) 5 Combine 3, Total DA to Forebay 6 Diversion Flow to Infiltration Basin 7 Diversion Flow to Wet Pond 8 Reservoir Wet Pond Routed 9 Combine 2, DA #1 - Total Proposed Post Routing 11 Reservoir Basin Plugged Routed 13 SCS Runoff DA #2 Existing 14 SCS Runoff DA #2 - Uncontrolled 15 SCS Runoff DA #2 - Controlled Drywell 16 Reservoir Drywell Routed 17 Combine 14, DA #2 - Total Proposed Post Routing 19 SCS Runoff DA #3 - Existing 20 SCS Runoff DA #3 - Uncontrolled Proj. file: Benmark Hydro.gpw Tuesday, Aug 16,

22 Hydraflow Rainfall Report Hydraflow Hydrographs by Intelisolve v9.02 Tuesday, Aug 16, 2016 Return Intensity-Duration-Frequency Equation Coefficients (FHA) Period (Yrs) B D E (N/A) File name: PennDOT.IDF Intensity = B / (Tc + D)^E Return Intensity Values (in/hr) Period (Yrs) 5 min Tc = time in minutes. Values may exceed 60. Rainfall Precipitation Table (in) Precip. file name: NOAA Franklin Twp.pcp Storm Distribution 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr SCS 24-hour SCS 6-Hr Huff-1st Huff-2nd Huff-3rd Huff-4th Huff-Indy Custom

23 SEDIMENT BASIN CALCULATIONS 19

24 This page intentionally left blank. 20

25 21

26 22

27 23

28 24

29 Hydrograph Summary Report Hydraflow Hydrographs by Intelisolve v9.02 Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval peak volume hyd(s) elevation strge used description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 1 Rational , DA to Sediment Basin 2 Reservoir , ,746 Basin Routed Benmark E&S.gpw Return Period: 10 Year Monday, Dec 7,

30 Hydrograph Summary Report Hydraflow Hydrographs by Intelisolve v9.02 Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval peak volume hyd(s) elevation strge used description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 1 Rational , DA to Sediment Basin 2 Reservoir , ,343 Basin Routed Benmark E&S.gpw Return Period: 25 Year Monday, Dec 7,

31 Hydrograph Summary Report Hydraflow Hydrographs by Intelisolve v9.02 Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph No. type flow interval peak volume hyd(s) elevation strge used description (origin) (cfs) (min) (min) (cuft) (ft) (cuft) 1 Rational , DA to Sediment Basin 2 Reservoir , ,023 Basin Routed Benmark E&S.gpw Return Period: 100 Year Monday, Dec 7,

32 Hydraflow Rainfall Report Hydraflow Hydrographs by Intelisolve v9.02 Monday, Dec 7, 2015 Return Intensity-Duration-Frequency Equation Coefficients (FHA) Period (Yrs) B D E (N/A) File name: PennDOT.IDF Intensity = B / (Tc + D)^E Return Intensity Values (in/hr) Period (Yrs) 5 min Tc = time in minutes. Values may exceed 60. Rainfall Precipitation Table (in) Precip. file name: Franklin Twp.pcp Storm Distribution 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr SCS 24-hour SCS 6-Hr Huff-1st Huff-2nd Huff-3rd Huff-4th Huff-Indy Custom

33 ANTI-SEEP COLLAR CALCULATIONS 29

34 This page intentionally left blank. 30

35 LENGTH OF PIPE IN THE SATURATED ZONE (L S ) L L L S S S = y * (z + 4) [1 + (pipe slope ft/ft /( pipe slope))] = 9 * (4 + 4) [1 + (0.025 / ( ))] = 9 *8 [ ] LS = 80.0 INCREASE IN FLOW PATH LF = 1.15 L L F LF = 92.0 S = 1.15 * 80.0 MINIMUM COLLAR PROJECTION Vmin = (L F L S ) / 2(no. of collars) V min = 12.0 / 4 Vmin = 3.0 SIDE DIMENSION (S) S = 2V + Barrel Diameter S = 2(3) S =

36 32

37 RIP-RAP CALCULATIONS 33

38 This page intentionally left blank. 34

39 35

40 36

41 37

42 Mannings "n" GOURMET'S DELIGHT OUTLET VELOCITY CALCULATIONS Pipe Diameter (ft) Flow Area (ft 2 ) Wetted Perimeter (ft) Slope (ft/ft) Velocity (fps) Structure Multiplier EW EW Level Spreader Infil. Basin

43 SOILS TABLE 39

44 This page intentionally left blank. 40

45 Soils Data Table PHYSICAL PROPERTIES SUITABILITY CHARACTERISTICS FOR ENGINEERING CONSTRUCTION GgB GeB2 Glenelg Channery Silt Loam 3-8% B Good Fair Road Subgrade Road Fill Resevoir Area Embankment Fair to Good Fair to Good Characteristics that affect Soil Mapping Unit Original Soil Mapping Unit Soil Series Description Slope Depth to Seasonal High Water Table Depth to Bedrock Hydrologic Soil Group Permeability Suitability to winter grading Resistance to frost action Suitability of material for Infiltration of waste from septic tanks Suitability for ponds and basins Building sites Resolutions Permeable Sub-Stratum Permeability Mulch or mat areas of disturbance GgC GeC3 Glenelg Channery Silt Loam 8-15% B Fair Fair Fair Fair to Good Shallow Soil Permeable Sub-Stratum Permeability Mulch or mat areas of disturbance GgD GeD2 Glenelg Channery Silt Loam 3-8% B Fair Fair Fair Fair to Good Shallow Soil Permeable Sub-Stratum Permeability Mulch or mat areas of disturbance 41

46 This page intentionally left blank. 42

47 WORKSHEET #22 PLAN WRITER CREDENTIALS 43

48 This page intentionally left blank. 44

49 Ronald Ragan, P.E Civil Engineering Purdue University Fall 2012 Designers Workshop Stormwater BMP Workshop BCCD BCCD 11 October April 2012 Ragan Engineering (610) Roy F. Weston, Inc. (610) Chatham Acres Chester London Grove Twp. PAI CCCD/PADEP Lighthouse Youth Center Chester Oxford Borough PAI CCCD/PADEP Hearne Hardwood Chester Lower Oxford Twp. PAI CCCD/PADEP 45