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SWPPP Only reduced STORMWATER MANAGEMENT REPORT and STORMWATER POLLUTION PREVENTION PLAN NARRATIVE NYSDEC GP-015-0-002 Prepared for: Clear Brook LLC 14-Lot Residential Subdivision Big Boom Road 316.14-1-6 Town of Queensbury Warren County, New York Prepared by: Hutchins Engineering 169 Haviland Road Queensbury, NY 12804 December 10, 2018 CERTIFICATION STATEMENT To be signed by contractors performing the site construction. I hereby certify under penalty of law that I understand and agree to comply with the terms and conditions of the SWPPP and agree to implement any corrective actions identified by the qualified inspector during a site inspection. I also understand that the owner or operator must comply with the terms and conditions of the most current version of the New York State Pollutant Discharge discharges from construction activities and that it is unlawful for any person to cause or contribute to a violation of water quality standards. Furthermore, I am aware that there are significant penalties for submitting false information that I do not believe to be true, including the possibility of fine and imprisonment for knowing violations. Name: __________________________________________________________ Company: _______________________________________________________ Title: ___________________________________________________________ Signature: _______________________________ Date: __________________ Each Sub-Contractor or additional Contractors completing site work must also sign below: Name: __________________________________________________________ Company: _______________________________________________________ Title: ___________________________________________________________ Area of Work & SWPPP Responsibilities: ______________________________ ________________________________________________________________ Signature: _______________________________ Date: __________________ Name: __________________________________________________________ Company: _______________________________________________________ Title: ___________________________________________________________ Area of Work & SWPPP Responsibilities: ______________________________ ________________________________________________________________ Signature: _______________________________ Date: __________________ TABLE OF CONTENTS 1.0 PROJECT DESCRIPTION 1 2.0 EXISTING SITE CONDITIONS 1 3.0 PROPOSED DEVELOPMENT 3 4.0 PROPOSED STORMWATER MANAGEMENT 3 5.0 NYSDEC REQUIREMENTS 4 5.1 Water Quality Volume 4 5.2 Runoff Reduction Volume 6 5.3 Planning for Green Infrastructure 6 5.4 Green Infrastructure Techniques for RRv 7 5.5 Runoff Reduction Volume Practices for Project 8 5.6 Channel Protection Volume 8 5.7 Overbank Flood Control 8 5.8 Extreme Storm Control 8 6.0 TOWN OF QUEENSBURY REQUIREMENTS 9 7.0 ENDANGERED SPECIES 9 8.0 ARCHAEOLOGICAL RESOURCES & HISTORIC PLACES 9 9.0 CONSTRUCTION PHASE EROSION PRACTICES 9 10.0 TEMPORARY EROSION & SEDIMENT CONTROL MEASURES 9 11.0 CONTROL OF LITTER, CONSTRUCTION DEBRIS & CONSTRUCTION CHEMICALS 10 12.0 SEQUENCE OF CONSTRUCTION 11 13.0 MAINTENANCE OF TEMPORARY EROSION & SEDIMENT CONTROL DEVICES 11 14.0 OPERATION & MAINTENANCE PLAN 11 15.0 PERMANENT EROSION CONTROL 12 1.0 PROJECT DESCRIPTION The project consists of a 14-lot rural residential subdivision of a vacant 144-acre parent parcel, and ultimate construction of 14 new single family homes, with driveways and associated utilities. Lot sizes range from 2.4 acres to 67 acres. The project site is adjacent to the Hudson River in the area known accessed from Big Boom Road in the Town of Queensbury, Warren County, New York. The site contains approximately 3,900 feet of frontage on the Hudson River. 2.0 EXISTING SITE CONDITIONS Presently, the project site is vacant, area of approximately 75 acres is entirely vacant and has been utilized only for timber production in the recent past. There are numerous earthen paths and drive areas which have generally served for timber harvesting purposes, and the area is entirely wooded. There is an area of ACOE wetlands in the central eastern portion of this area which are being avoided in the project design. been the site of previous timber harvesting. The area is bisected by a canal and contains significant ductile iron water main which conveys water from the Town of Queensbury to the Town of Moreau, located immediately across the Hudson River. The water line is located within a non- exclusive easement granted to the Town of Queensbury from the property owners. Thirteen of the proposed fourteen building lots will be created in the area of the parcel with the lower area containing only one proposed parcel, at 66.7 acres. Site slopes are generally slight to moderate, 0-10% over the upper and lower areas of the property with a steep embankment, greater the 25% separating the two areas. The existing site drainage patterns over the upper area are generally west to east across the several hundred feet to the Hudson River. There are two distinct drainage channels that develop toward the eastern portion of the area which have been modelled as design points 1, 2 and 3. These three design points encompass the entire upper area and 13 of the 14 proposed building lots. As the lower area consisting of 66.7 acres is to remain largely undeveloped, the stormwater runoff model includes the site of the proposed residence and surrounding area, approximately 5.2 acres. Site soils in the upper area are mapped as primarily Oakville, HSG A, which are deep, well drained soils with relatively high permeability. There is a small portion in the northeast corner of the upper area mapped as Middlebury, HSG B. Field conducted test pits and infiltration and percolation tests indicate a larger portion of HSG B soils than mapped and design is reflective of the actual soils encountered. Soils in the lower area, near the proposed building site, are mapped as Middlebury, HSG B. Soils in remaining portions of the lower area are mapped as Middlebury, HSG B, Agawam, HSG B, and Fluvaquents (frequently flooded) A copy of the USDA soils map is included in the appendix of this report. Soil test pits, percolation tests and infiltration tests are indicated on the plans. 1 Drainage design points The site is broken into four drainage design points: 1L Easterly runoff to Hudson River from Subcatchment 1 2L Easterly runoff to Hudson River from Subcatchment 2 running thru Subcatchment 1 3L Easterly runoff to Hudson River from Subcatchment 3 4L Westerly runoff to Hudson River via canal from Lot 14 building area Existing Conditions Calculated Stormwater Runoff from the Site 1L (To river via north channel 14.28 acres) 1-year design storm (2.2") 0.0 CFS 0.0 acre-feet 10-year design storm (3.6") 0.07 CFS 0.057 acre-feet 25-year design storm (4.4") 0.36 CFS 0.207 acre-feet 100-year design storm (6.1") 3.68 CFS 0.773 acre-feet Existing Conditions Calculated Stormwater Runoff from the Site 2L (Big Boom Road West Central 24.023 Acres) 1-year design storm (2.2") 0.0 CFS 0.0 acre-feet 10-year design storm (3.6") 0.0 CFS 0.0 acre-feet 25-year design storm (4.4") 0.10 CFS 0.077 acre-feet 100-year design storm (6.1") 1.42 CFS 0.638 acre-feet Existing Conditions Calculated Stormwater Runoff from the Site 3L (To River via East Channel 18.52 acres ) 1-year design storm (2.2") 0.0 CFS 0.0 acre-feet 10-year design storm (3.6") 0.29 CFS 0.186 acre-feet 25-year design storm (4.4") 1.61 CFS 0.471 acre-feet 100-year design storm (6.1") 9.42 CFS 1.403 acre-feet Existing Conditions Calculated Stormwater Runoff from the Site 4L (Lot 14 Site area 5.24 acres ) 1-year design storm (2.2") 0.09 CFS 0.044 acre-feet 10-year design storm (3.6") 1.99 CFS 0.251 acre-feet 25-year design storm (4.4") 3.94 CFS 0.422 acre-feet 100-year design storm (6.1") 9.20 CFS 0.868 acre-feet Total Site Runoff - Existing Conditions (Sum of 4 Links) 1-year design storm (2.2") 0.09 CFS 0.044 acre-feet 10-year design storm (3.6") 2.35 CFS 0.494 acre-feet 25-year design storm (4.4") 6.01 CFS 1.177 acre-feet 2 100-year design storm (6.1") 23.72 CFS 3.68 acre-feet 3.0 PROPOSED DEVELOPMENT Proposed Conditions Summary Total Project Site Area: 145 Acres Buildings Coverage: 43,000 SF Driveways: 135,000 SF Total Impervious: 178,000 SF 4.0 PROPOSED STORMWATER MANAGEMENT NYSDEC SPDES requirements for stormwater discharges from construction activities in accordance with GP-0-015-02 must be applied to the project. Specifically, for single-family residential subdivisions that disturb over 5 acres, a Stormwater Pollution Prevention Plan including post-construction stormwater management practices must be developed and implemented. Stormwater management practices are applied in the form of a series of vegetated pretreatment forebay areas and small, vegetated infiltration basins are utilized for each driveway and house site area. An infiltration rate of 20 inches per hour is utilized in the infiltration basins. Runoff calculations have been prepared utilizing SCS TR-20 methodology and HydroCAD analysis software for the 1-year, 10-year, 25-year, and 100-year Type-II simulated rainfall distributions. Criteria utilized in the analysis are summarized as follows: Design Storm Events 1-year 24-hr Type-II distribution 2.2" 10-year 24-hr Type-II distribution 3.6" 25-year 24-hr Type-II distribution 4.4" 100-year 24-hr Type-II distribution 6.1" Proposed Conditions Calculated Stormwater Runoff from the Site 1L (To river via north channel 14.28 acres) 1-year design storm (2.2") 0.0 CFS 0.0 acre-feet 10-year design storm (3.6") 0.07 CFS 0.052 acre-feet 25-year design storm (4.4") 0.33 CFS 0.190 acre-feet 100-year design storm (6.1") 3.57 CFS .736 acre-feet 3 Proposed Conditions Calculated Stormwater Runoff from the Site 2L (Big Boom Road West Central 24.023 Acres) 1-year design storm (2.2") 0.0 CFS 0.0 acre-feet 10-year design storm (3.6") 0.0 CFS 0.0 acre-feet 25-year design storm (4.4") 0.09 CFS 0.066 acre-feet 100-year design storm (6.1") 1.28 CFS 0.551 acre-feet Proposed Conditions Calculated Stormwater Runoff from the Site 3L (To Rier via East Channel 18.52 Acres) 1-year design storm (2.2") 0.0 CFS 0.0 acre-feet 10-year design storm (3.6") 0.28 CFS 0.179 acre-feet 25-year design storm (4.4") 1.55 CFS .462 acre-feet 100-year design storm (6.1") 9.96 CFS 1.401 acre-feet Proposed Conditions Calculated Stormwater Runoff from the Site 4L (Lot 14 Site Area = 5.24 Acres) 1-year design storm (2.2") 0.09 CFS .041 acre-feet 10-year design storm (3.6") 1.87 CFS .236 acre-feet 25-year design storm (4.4") 3.70 CFS 0.396 acre-feet 100-year design storm (6.1") 8.63 CFS .814 acre-feet Total Site Runoff - Proposed Conditions (Sum of 4 Links) 1-year design storm (2.20") 0.09 CFS .041 acre-feet 10-year design storm (3.80") 2.22 CFS 0.467 acre-feet 25-year design storm (4.40") 5.67 CFS 1.114 acre-feet 100-year design storm (5.40") 23.44 CFS 3.502 acre-feet The developed site has been modeled as a series of subcatchments (drainage areas) and ponds, as shown on the HydroCAD drainage diagram. Full results of stormwater runoff computations are attached to this report. 5.0 NYSDEC REQUIREMENTS 5.1 Water Quality Volume The water quality volume (WQv) as required by NYSDEC is designed to capture and pre-treat the 90% rainfall event and is calculated as a function of the impervious areas of the drainage 4 subcatchments for the project site. The portions of the site which will remain as vacant forestland are not considered in the WQv calculations. Water quality volumes are provided in the shallow vegetated infiltration basins located along driveways and around house sites. Subcatchment WQv Required Provided Location 1382 CF 1DP Lot 1 Drive 1D Lot 1 Drive 356 CF 1HP Lot 1 House 747 CF 1H Lot 1 House Area 500 CF Area 684 CF 2DP Lot 2 Drive 2D Lot 2 Drive 570 CF 2HP Lot 2 House 1041 CF 2H Lot 2 House Area 500 CF Area 1558 CF 3DP Lot 3 Drive 3D Lot 3 Drive 998 CF 3HP Lot 3 House 562 CF 3H Lot 3 House Area 500 CF Area 4P Lot 4 Pond 4D - Lot 4 Drive 855 CF 3800 CF 4P Lot 4 Pond 4H Lot 4 House Area 500 CF 1049 CF 5DP Lot 5 Drive 5D Lot 5 Drive 855 CF 5HP Lot 5 House 1721 CF 5H Lot 5 House Area 500 CF Area 1288 CF 6DP Lot 6 Drive 6D Lot 6 Drive 855 CF 6HP Lot 6 House 1721 CF 6H Lot 6 House Area 501 CF Area 1825 CF 7DP Lot 7 Drive 7D Lot 7 Drive 579 CF 7HP Lot 7 House 1245 CF 7H Lot 7 House Area 501 CF Area 725 CF 8DP - Lot 8 Drive 8D Lot 8 Drive 475 CF 8HP Lot 8 House 1475 CF 8H Lot 8 House 686 CF Area 9DS Lot 9/10 Shared 9DP Lot 9/10 Shared 1594 CF 998 CF Drive Drive 9HP Lot 9 House 1271 CF 9HS Lot 9 House Area 1022 CF Area 10HS - Lot 10 House 10HP Lot 10 House 2138 CF 1165 CF Area Area 5 11S Lot 11 House & 2430 CF 11P Lot 11 1308 CF Drive 12S Lot 12 House & 1995 CF 12P Lot 12 1074 CF Drive 13S Lot 13 House & 1759 CF 13P Lot 13 1074 CF Drive 1185 CF 14P Lot 14 14S Lot 14 House Area 876 CF Total WQv required: 17,248 CF Total WQv provided: 33,195 CF 5.2 Runoff Reduction Volume Runoff Reduction Volume (RRv) as required by NYSDEC prescribes the design goal to reduce the Water Quality Volume through the allowable standard and green infrastructure practices. The minimum RRv requirement is calculated as a function of the 90% rainfall event, the soil Hydrological Classification and impervious cover. RRv = P x 0.95 x S x (Ai/12) = 1.2" x 0.95 x 0.47 (A&B-soils) x (4.08 ac/12) Minimum RRv required: 7935 CF 5.3 Planning for Green Infrastructure NYSDEC requires that Planning Practices for Preservation of Natural Features and Conservation be considered and evaluated for the project layout and stormwater management practices. Specifically these six practices are evaluated as follows: 1. Preservation of Undisturbed Areas Much of the downgradient areas surrounding the building sites will be preserved as native forest space in order to maintain the rural character of the project 2. Preservation of Buffers Buffers are maintained between structures and river and canal shore areas. 3. Reduction of Clearing and Grading The proposed house sites have been carefully designed to fit with the existing topography and features in order to maintain privacy and while minimizing required clearing and grading. 4. Locating Development in Less Sensitive Areas The proposed development will be constructed over the flatter portions of the site, while the natural steep slopes, wetlands, and sensitive areas are avoided. 5. Open Space Design 6 The proposed development proposes the locations of the house sites to be constructed over the appropriate areas portions of the site, with significant portions of the site being preserved as open, forested space. 6. Soil Restoration Vegetated areas which are compacted through earthwork processes around the houses will undergo soil restoration treatments to restore the long-term infiltration over these areas. 5.4 Green Infrastructure Techniques for RRv NYSDEC requires that each of the 11 Green Infrastructure practices be evaluated for feasibility for the project. 1. Conservation of Natural Areas As stated above, much of the site will be preserved in its natural, forested state. 2. Sheet Flow to Riparian Buffers or Filter Strips areas remain undisturbed. 3. Vegetated Swale Roadside vegetated swales will be constructed, which will receive runoff from the roadway and the surrounding house sites, however RRv credits are taken in the infiltration basins. 4. Tree Planting / Tree Pit RRv credit is taken in the lot specific rain gardens and any lot specific plantings would have minimal effect upon RRv, therefore this practice is not considered in the calculations. 5. Disconnection of Rooftop Runoff Runoff from the roof areas will sheet flow over the surrounding yard area and into the respective rain gardens. As RRv credit cannot be taken in multiple practices for the same areas, the disconnection is not considered in the RRv calculations. 6. Stream Daylighting There are no proposed stream or water body crossings or obstructions on the project site and the stream west of the project area will not be disturbed. 7. Rain Gardens Rain gardens (shallow vegetated infiltration basins) are proposed for the lots are sized for 100% of the contributing Water Quality Volume. 8. Green Roofs Due to cost and maintenance, vegetated roofs are not feasible for these residential buildings. 9. Stormwater Planters 7 Stormwater planters might be feasible for the roof areas, however RRv credit is already taken in the rain gardens. 10. Rain Barrels and Cisterns Rain Barrels and cisterns are not feasible for the roof areas, as the storage volume for even the water quality rain event is quite large, thus incurring significant cost and maintenance. 11. Porous Pavement Runoff from the roadway and individual driveways is managed in the infiltration basin due to the excellent soil conditions. 5.5 Runoff Reduction Volume Totals Total WQv Required: 17,248 CF Minimum RRv Required: 7935 CF RRv Practices: Infiltration: 17,248 CF (62-ac contributory, 4.1-ac impervious) Total RRv Provided: 17248 CF (100%+ of WQv) As the infiltration facilities are sized to contain and infiltrate in excess of the water quality volume, without reaching the outlet elevation, then 100% of the WQv is also infiltrated, thus satisfying the RRv goals. 5.6 Channel Protection Volume Channel protection volume (Cpv) as required by NYSDEC requires the extended detention of the post-developed 1-year, 24-hour storm. As the infiltration facilities manage the larger storm events with no outflow, the 1-year design Channel Protection Volume design goals are met. 5.7 Overbank Flood Control Overbank flood control as required by NYSDEC requires that the peak developed discharge rate from the 10-year, 24-hour storm not exceed the pre-development rate. Existing 10-year peak storm discharge: 2.35 CFS (Total Site) Developed 10-year peak storm discharge: 2.22 CFS (Total Site) The 10-year storm calculations show that the overbank flood control requirement is met. 5.8 Extreme Storm Control 8 Extreme storm control as required by NYSDEC requires that the peak developed discharge rate from the 100-year, 24-hour storm not exceed the pre-development rate. Existing 100-year peak storm discharge: 23.72 CFS (Total Site) Developed 100-year peak storm discharge: 23.44 CFS (Total Site) The 100-year storm calculations show that the overbank flood control requirement is met. 6.0 TOWN OF QUEENSBURY REQUIREMENTS The Town of Queensbury requires that the peak developed discharge rate from the 25-year, 24- hour storm not exceed the pre-development rate. Existing 25-year peak storm discharge: 6.01 CFS Developed 25-year peak storm discharge: 5.67 CFS The 25-year storm calculations show that the Town of Queensbury requirement is met. 7.0 ENDANGERED SPECIES In accordance with Part I.D.4 of GP-015-0-002, NYSDEC EAF mapper, question E2.o indicates that there are no endangered or threatened species or identified habitat known to exist on subject site. This letter is included in the appendix of this report. 8.0 ARCHAEOLOGICAL RESOURCES & HISTORIC PLACES In accordance with Part III.A.8 of GP-015-0-002, an inquiry to NYSOPRHP was made for a determination upon historic and cultural resources and a Phase I study was requested by NYSOPRHP, which was undertaken. The Phase I study has been completed and report has been forwarded to NYSOPRHP. 9.0 CONSTRUCTION PHASE EROSION PRACTICES Practices to be implemented during construction for erosion and sediment control include silt fencing and temporary sediment basins in various portions of the total disturbed area. Silt fencing will be placed across slopes (on the contour) in all areas downgrade of disturbed areas. Temporary sediment traps will be utilized in areas where construction phase runoff concentrates. 10.0 TEMPORARY EROSION & SEDIMENT CONTROL MEASURES Erosion and sediment control measures will be incorporated into the construction of the project. These practices will comply with the New York State Department of Environmental blue book). Separate erosion and sediment controls will be installed for each phase of construction. The following temporary erosion and sediment control devices are to be utilized: 1. Sediment Control Fence 9 Silt Fence shall be used to control erosion from sheet flow on slopes not to exceed 1 on 3. Concentrated flows shall not be directed toward the silt fence. The silt fence must be installed parallel to the contour lines to eliminate drainage along the fence. 2. Temporary Sediment Basin Basins will be excavated below each house site and seeded with ryegrass to accept stormwater runoff from the construction site allowing sediment to settle out. Sediment traps shall be constructed in the location and be of the size and type specified to collect sediment laden stormwater. 3. Temporary Seeding Land that is stripped of vegetation will be seeded and planted as soon as possible. Any area that will remain cleared but not under construction for five days or longer will be seeded with a ryegrass mixture and mulched to stabilize soil until construction resumes. 4. Temporary Diversion Swales Temporary diversion swales shall be constructed either to divert clean stormwater runoff from newly-graded areas or to direct sediment laden runoff to a sediment trapping device. 5. Dust Control Measures for dust control during construction shall be implemented as needed. Daily water sprays will be used during dry conditions. In addition to water sprays, temporary mulching, temporary seeding and covering stockpiles with tarps shall be implemented when necessary. 6. Erosion Control Blanket Fabricated straw or biodegradable mesh blankets shall be utilized to protect and temporarily stabilize slopes of 1:3 or greater and shall be applied to graded, topsoiled, and seeded slopes. Blankets will be attached with staples or stakes in accordance with Blankets on cut slopes and vegetated ditchlines will be maintained in place permanently and allowed to biodegrade. 11.0 CONTROL OF LITTER, CONSTRUCTION DEBRIS & CONSTRUCTION CHEMICALS During the course of construction, the site shall be kept clear of debris and litter which could be transported by water or wind. This material shall be picked up daily and shall be stored in waste debris containers where it will be securely held. All petroleum products or other waste contaminants which are water soluble, or could be dispersed and transported by stormwater, shall be stored in covered containers and shall be regularly removed from the site and properly and legally disposed of. All petroleum or other hazardous materials shall be stored and handled in conformance with NYSDEC spill prevention and containment requirements. 10 12.0 SEQUENCE OF CONSTRUCTION Prior to the start of construction, the contractor shall install the sediment control fence along the low side of each area to be disturbed in order to contain runoff from the construction site. Temporary sediment basins are to be constructed as shown on the plans and shall collect stormwater runoff from all areas of proposed road and utility construction. The temporary sediment basins shall be a minimum of 3600 CF per acre of disturbance. Basins shall allow collected water to filter into the existing soil; if necessary, sediment will be cleaned out of the basins to maintain their infiltrative capability. Following the completion of all planting and the establishment of all grass areas, any collected sediment and sediment control fencing shall be removed. Any debris from the perimeter of the site shall be removed and dispose of all waste material shall be disposed of in a legal manner. 13.0 MAINTENANCE OF TEMPORARY EROSION & SEDIMENT CONTROL DEVICES The sediment basins shall be inspected at least weekly and after every rain event by the contractor. When 50% of the volume of the trap is full, the contractor shall remove collected sediment and dispose of properly. The contractor shall inspect the sediment control fence weekly and after every rain event and remove trapped sediment and maintain the devices such that they are in good working order. 14.0 OPERATION & MAINTENANCE PLAN For devices serving common shared driveways, t responsible to provide the maintenance in the settling/pretreatment basin and infiltration basin, ditchlines and culverts. Maintenance includes trimming of vegetation in the ditchlines, basins and sediment removal in the ditches, culverts and pond. Trimming should be performed as needed throughout the spring, summer and fall, typically monthly or semi-monthly. Sediment removal and inspection of the stormwater infrastructure should be performed annually. Each respective lot owner is to provide the maintenance needed in order to ensure continuous and effective operation of the stormwater control practices on the respective lots. Maintenance includes vegetation trimming and sediment removal in the rain gardens. Mowing and trimming should be performed as needed throughout the spring, summer and fall, typically weekly or semi-weekly. Sediment removal and inspection of the rain gardens should be performed annually or as needed due to surrounding and contributing site conditions. If long-term infiltration capacity becomes reduced, the organic topsoil is to be excavated and new soil installed. A common area maintenance agreement will be prepared and reviewed by the town and will be signed by each respective lot owner at the time of the deed conveyance and will be filed in the 11 15.0 PERMANENT EROSION CONTROL All pervious areas shall be graded, topsoil installed and seeded or planted as soon as practical, but in no case shall finish graded soils be exposed for more than five days. Seed beds shall be mulched with straw and plant beds shall be mulched with pine bark mulch. Seeded areas on slopes over 1:3 shall be stabilized with erosion control blankets as specified on the plans. 16.0 INSPECTION REQUIREMENTS In accordance with Part IV of GP-0-15-002, the owner or operator of each construction activity shall have a trained contractor inspect the erosion and sediment control practices within the active work area on a daily basis to ensure that proper maintenance and functionality is realized for the practices. If soil disturbances upon the site have been temporarily suspended and proper stabilization methods have been implemented, the trained contractor may suspend inspections until site work is restarted. In addition, a qualified inspector (Licensed Professional Engineer, CPESC or Registered Landscape Architect; or someone working under their direct supervision who has received four hours of DEC endorsed training) shall conduct site inspections at least once every (7) calendar days. If soil disturbances upon the site have been temporarily suspended and proper stabilization methods have been implemented, the qualified inspector shall conduct site inspections at least once every (30) calendar days. If soil disturbances have been shut down for 2-years with partial project completion and proper stabilization methods have been implemented, a Notice of Termination can be filed with DEC. These site inspections shall continue until the project is completed, final site stabilization is achieved, and a Notice of Termination is filed with DEC. 12 ATTACHMENTS Site Soils Maps Water Quality Volume Computations Subcatchment Map Existing Model HydroCAD Existing Subcatchment Map Proposed Model HydroCAD Proposed HYDROCAD Existing & Proposed Conditions: Type-II 24 hr Rainfall = 2.2-year), 3.6-year), 4.425- year), 6.1-year) USDA Soil Map Warren County GIS Soil Map Inputs 1.2P =1.2 100I = 100 0.09A =0.24 Calculated3,750SF TOTALCalculated10,500SF TOTAL calc Rv =0.95Rv minimum = 0.2calc Rv =0.95Rv minimum = 0.2 app Rv =0.95app Rv =0.95 0.008Acre-feetWQv =0.023Acre-feet 356CFminimumWQv = 998CFminimum SUBCATCHMENT 1H - LOT 1 HOUSE AREASUBCATCHMENT 4D - LOT 4 DRIVE Inputs 1.2P =1.2 50I = 100 0.23A =0.21 Calculated10,000SF TOTALCalculated9,000SF TOTAL calc Rv =0.50Rv minimum = 0.2calc Rv =0.95Rv minimum = 0.2 app Rv =0.50app Rv =0.95 0.011Acre-feetWQv =0.020Acre-feet 500CFminimumWQv = 855CFminimum SUBCATCHMENT 2D - LOT 2 DRIVE SUBCATCHMENT 4H - LOT 4 HOUSE AREA Inputs 1.2P =1.2 100I = 50 0.14A =0.23 Calculated6,000SF TOTALCalculated10,000SF TOTAL calc Rv =0.95Rv minimum = 0.2calc Rv =0.50Rv minimum = 0.2 app Rv =0.95app Rv =0.50 0.013Acre-feetWQv =0.011Acre-feet 570CFminimumWQv = 500CFminimum SUBCATCHMENT 2H - LOT 2 HOUSE AREASUBCATCHMENT 5D - LOT 5 DRIVE Inputs 1.2P =1.2 50I = 100 0.23A =0.21 Calculated10,000SF TOTALCalculated9,000SF TOTAL calc Rv =0.50Rv minimum = 0.2calc Rv =0.95Rv minimum = 0.2 app Rv =0.50app Rv =0.95 0.011Acre-feetWQv =0.020Acre-feet 500CFminimumWQv = 855CFminimum SUBCATCHMENT 3H - LOT 3 HOUSESUBCATCHMENT 5H - LOT 5 HOUSE Inputs 1.2P =1.2 50I = 50 0.23A =0.23 Calculated10,000SF TOTALCalculated10,000SF TOTAL calc Rv =0.95Rv minimum = 0.2calc Rv =0.57Rv minimum = 0.2 app Rv =0.95app Rv =0.57 0.020Acre-feetWQv =0.016Acre-feet 855CFminimumWQv = 686CFminimum SUBCATCHMENT 6H - LOT 6 HOUSESUBCATCHMENT 9D - LOT 9 & 10 DRIVE SHARED Inputs 1.2P =1.2 50I = 100 0.23A =0.24 Calculated10,000SF TOTALCalculated10,500SF TOTAL calc Rv =0.50Rv minimum = 0.2calc Rv =0.95Rv minimum = 0.2 app Rv =0.50app Rv =0.95 0.012Acre-feetWQv =0.023Acre-feet 501CFminimumWQv = 998CFminimum SUBCATCHMENT 7D - LOT 7 DRIVESUBCATCHMENT 9H - LOT 9 HOUSE AREA Inputs 1.2P =1.2 100I = 67.7 0.14A =0.36 Calculated6,000SF TOTALCalculated15,500SF TOTAL calc Rv =0.95Rv minimum = 0.2calc Rv =0.66Rv minimum = 0.2 app Rv =0.95app Rv =0.66 0.013Acre-feetWQv =0.023Acre-feet 579CFminimumWQv = 1,022CFminimum SUBCATCHMENT 7H - LOT 7 HOUSE AREASUBCATCHMENT 10H - LOT 10 HOUSE Inputs 1.2P =1.2 50I = 70.6 0.23A =0.39 Calculated10,000SF TOTALCalculated17,000SF TOTAL calc Rv =0.50Rv minimum = 0.2calc Rv =0.69Rv minimum = 0.2 app Rv =0.50app Rv =0.69 0.012Acre-feetWQv =0.027Acre-feet 501CFminimumWQv = 1,165CFminimum SUBCATCHMENT 8D - LOT 8 DRIVESUBCATCHMENT 11S - LOT 11 Inputs 1.2P =1.2 100I = 73 0.11A =0.42 Calculated5,000SF TOTALCalculated18,500SF TOTAL calc Rv =0.95Rv minimum = 0.2calc Rv =0.71Rv minimum = 0.2 app Rv =0.95app Rv =0.71 0.011Acre-feetWQv =0.030Acre-feet 475CFminimumWQv = 1,308CFminimum Calculated16,000SF TOTALCalculated14,000SF TOTAL calc Rv =0.67Rv minimum = 0.2calc Rv =0.63Rv minimum = 0.2 app Rv =0.67app Rv =0.63 0.025Acre-feetWQv =0.020Acre-feet 1,074CFminimumWQv = 876CFminimum SUBCATCHMENT 13S - LOT 13 1.2 69 0.37 Calculated16,000SF TOTAL calc Rv =0.67Rv minimum = 0.2 app Rv =0.67 0.025Acre-feet 1,074CFminimum