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HomeMy WebLinkAboutWPO201800060 Plan - VSMP Stormwater Management Plan 2019-02-08LINETYPE & SYMBOL LEGEND CONTOUR LINE - PROPERTY BOUNDARY o SETBACK UNDERGROUND UTILITY -------------.------- STREAM BUFFER DRAINAGE DIVIDE `� S AE ("0N,S'7_'R,,UCTI0N ENTRANCE 70' MIN, EXISTING A� PAVEMENT 3 �r 5:1 - FILTER CLOTH`' 6" MIN. A MOUNTABLE BERM (OPTIONAL) SIDE ELE � ATE 0C`,] EXISTING GROUND 70' Mirl, B WASHRACK (OPTIONAL) la` MIN. 10, MIIV. Lvm12' PiIN. a - - �— EXISTING PAVEMENT VDOT #I POSITIVE DRAINAGE 10' MIN, COURSE AGGREGATE B TO SEDIMENT TRAPPING DEVICE 1 * LIUST EXTEND FULL WIDTH OF INGRESS AND EGRESS PLAN OPERATION �� � VIEW I Z' MIN. I'vlTL LEE3'" f 0 3" MIN. FILTER r_LOTH J SECTION A -A iiv���JJ 7�Jn�fCJ�k�G� P.EINFORCED CONCRETE 'DRAIN SPACE SECT1101v1 8-B SOURCE: AfUAPTPU from 1983 Maryland Standards for Soil erosion and Sediment Control, and Va. )SWC Plate 3.02-1 CONSTRUCTION ENTRANCE DETAIL SCALE: NONE (W-ITH TI/71JR-E, SUPPO-Hr-r) 1. `-ET POSTS AND FKAVATE A 4"X4" 2. STAPLE WIRE FENCING TO THE POSTS. TRENCH UPSLOPE ALONG THE LINE OF POSTS. 1 "- FLOW 4,. 3. ATTACH THE FILTER FABRIC TO THE WIRE 4. BACKFILL AND COMPACT THE FENCE AND EXTEND IT INTO THE TRENCH. EXCAVATED SOIL. o v - FILOW EXTENSION OF FABRIC AND WIRE INTO THE TRENCH. FILTER FABRIC WIRE Ire SOURCE: Adapted from Installation of Straw and Fabric Filter Barriers for Sediment Controt, PLATE. 3.05-1 Sherlroud & �7ya.ni SILT FENCE DETAIL SCALE: NONE LINETYPE & SYMBOL LEGEND CONTOUR LINE PROPERTY BOUNDARY — — — SETBACK UNDERGROUND UTILITY STREAM BUFFER SOIL TYPE BOUNDARY ®- ---- -- --- — ---- --- -- — — — --- --- LIMIT OF GRADING — — TREE LINE 4 PRECAST CONCRETE SPLASH BLOCK -1 .2 SCALE: NONE PROPERTY LI I C 25' SIDE YARD SETBACK J j j r 1 1 1 1 � 1 r yak � DISTURBED AREA: 0.92 ARES NEW WELL, MIN FRC �k CONSTRUCTION ENTRANCE 3.02 V CONSTRUCTION ROAD STABILIZARION 3.03 SILT FENCE 3.05 SI X X TEMPORARY SEEDING 3.31 TS PERMANENT SEEDING 3.32 MULCHING 3,35 SOIL TYPE COX-X- RUNOFF VOLUMES, CONCENTRATED ROOF LEADER / FLOW TRANSITIONS TO SHEET FLOW PRIOR TO LOD u IN THE POST —DEVELOPED CONDITION. f -1024- / RESERVE AREA EROSION & SEDIMENT CONTROL & SWPPP PLAN BASEMAP SOURCE: COUNTY GIS SCALE: Ill = 20'-0" WER/DATA TE W/ DOMINION ENERGY i REQUIRED ,ATION OF SEPTIC 3TEM PER REPORT BY E a N U d � N � N (13 Q M J 70 �rztn-� .. L% Q_ c- N Qa .0) -I -e LL! a 3 c— f � �� (� w U) W 'd 00 V) F-- S— W �75 cp ry- CD = m Q U C'") �r IT Q G. (LARK GATHRICHT LiC.-J) /r. z �i _W cz n w�-- 0 CID o a Cry,. CCS L u (D _ UJI �i ([ v ) ■� CLczz U) = o ui REVISIONS: 07-30-18 08-01-18 11-12-18 DATE: 07-29-18 DRAWING NUMBER: C- SHEET 4 OF 7 Erosion and Sediment Control Narrative For: 6540 Mint Springs Park TM 55 Parcel 28 Albemarle County, VA HUC: Mechums River - Beaver Creek 020802040102 LAT: 38e 5° 8"N LONG. 78' 43' 50'W Project Description: The proposed work includes clearing and grubbing 0.87 acres of a partially cleared wooded area, and the grading necessary to construct a maintenance building and gravel work yard for vehicular access and equipment storage. The total area of the parcel is 455.46 acres. The total on -site disturbed area is approximately 0.92 acres, with 0.68 acres being impervious surface. Work is anticipated to begin in the Spring of 2019. Erosion control measures shown will protect the stream and property below from receiving silt -laden runoff. Existing Site Conditions: The project site area is on a wooded area and generally slopes to the east at 8%. The pre and post drainage patterns will be essentially the same. Adjacent Property: The property is surrounded by other large acreage properties with mountainous wooded areas. Off -site Areas: No off -site areas will be utilized. Soils: 82C-Thurmont very stony silt loam, 0.32 K®Factor, Group B soil 9OB®Unisom very stony silt loam, 0.37 K-Factor, Group B soil 90C-Unisom very stony silt loam, 0.37 K-Factor, Group B soil Critical Erosion Areas: There are no critical erosion areas in the project area. Soil Stockpiles: No soil stockpiles are anticipated. The site will be graded to balance cut and fill. Erosion and Sediment Control Measures: Unless otherwise indicated, all vegetative and structural erosion and sediment control practices will be constructed and maintained according to minimum standards and specifications of the Virginia Erosion and Sediment Control Handbook. Additional measures may be required during construction by the Erosion Control Inspector, as needed. Structural Practices: Construction Entrance: (CE) 3.02 (To be installed where construction site traffic exits the project area, to remove soil from tires prior to travel on public roads. The contractor shall clean and maintain the travelway as required to keep soil frorn washing into unprotected areas and to provide a safe surfcece for pedestrian and vehicular access. The Construction Entrance will be located within the footprint of the existing building to protect the adjacent paved travelways. Once the building is erected, all adjacent areas will be stabilized and the construction entrance will no longer be necessary.) Construction Raad Stabilization: (CRS) 3.03 The temporary stabilization of access roads with stone immediately. (To be installed along existing access road to provide construction access around the building site in travelways and lay -down areas.) Silt Fence.. (SF) 3.05 Silt fence (wire -supported) shall be constructed along the lower limit of graded areas. (To be installed as shown on the plan, down -gradient of distcirbed areas created by the proposed work, and above the proposed excavation to prevent up -gradient runoff from crossing disturbed areas. ) Permanent Seeding (PS) 3.32 Establishment of pereraiial vegetative cover by planting seed where permanent, long-lived vegetative cover is needed on fine -graded areas. (Permanent seeding will be provided on all disturbed areas designated to be landscaped on the site plan within 7 days of final grading.) Mulching (MU) 3.35 Application of plant residues to distw-bed surfaces to prevent erosion and reduce overland flow. Apply to all seeded areas. Refer to Table 3.35-A on Sheet C-3.3 for application rates. (To be installed along with Permanent Seeding) Vegetative Practices: Temporary Seeding 3.31: All areas disturbed by construction that will not be brought to final grade for a period of more than 14 days, will be stabilized by establishing a good stand of grass. Lime 3.31: Unless it is known that the site will remain undisturbed for many months, lime is not necessary. If necessary, the amount will be determined by Soil Test, or 3 tons per acre of pulverized agricultural limestone, uniformly applied to surface to be seeded during seedbed preparation and incorporated into the top 2-4 inches of soil. Fertilizer 3.31: 600 pounds per acre of 10-20-10 or equivalent, uniformly applied to the euffdce to be seeded during seedbed preparation and incorporated into the top 2-4 inches of soil. Surface roughening 3.31: Where disturbed soils have been compacted, loosen soils by discing, raking, or whatever acceptable means available to receive seed. Seed 3.31: Seed shall be broadcast evenly and planted from 9 to X inch deep. Seasonal seed selection shall be as follows: • Sept. 1 - Feb. 15: 50/50 Mix of Annual Rye and Winter Rye, 50-100 lb/ac. Feb. 16 - April 30: use Annual Rye, 60-100 Ib/ac. ® May 1 - Aug. 31: use German Millet, 50 Ib/ac. Areas which fail to establish vegetative cover adequate to prevent rill erosion will be reseeded as soon as such areas are identified. Management Strategies: Construction should be sequenced so that grading operations can begin and end as quickly as possible. Areas that are not to be disturbed shall be clearly marked by the placement of the erosion control measures prior to construction. The job superintendent shall be responsible for the installation and maintenance of all erosion and sediment measures. Where construction vehicle access routes intersect paved public roads, provisions shall be made to minimize the transport of sediment by vehicular tracking onto the paved surface. Where sediment is transported onto a public road surface, the road shall be cleaned thoroughly at the end of each day. Sediment shall be removed from the roads by shoveling or sweeping and transported to a sediment control disposal area. Street washing shall be allowed only after sediment is removed in this manner. Stabilization of Denuded Areas and Soil Stockpiles: Permanent or temporary soil stabilization must be applied to denuded areas within 7 days after final grade is reached on any portion of the site. Temporary soil stabilization shall be applied within 7 days to denuded areas which may not be at final grade but will remain dormant (undisturbed) for longer than 14 days. Permanent stabilization shall be applied to areas that are to be left dormant for more than one year. Soil stabilization refers to measures that protect soil from the erosive forces of raindrop impact and flowing water. Applicable practices include vegetative establishment, mulching and the early application of gravel base on areas to be paved. Soil stabilization measures should be selected to be appropriate for the time of year, site conditions and estimated duration of use. Timing and Stabilization of Sediment Trapping Measures: Sediment barriers 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. Stabilization measures shall be applied to earthen structures such as dams, dikes, and diversions immediately after installation. Disposal of Temporary Measures: All temporary erosion and sediment control measures shall be removed within 30 days after final site stabilization or after the temporary measures are no longer needed, unless otherwise authorized by the local program administrator. Trapped sediment and the disturbed soil areas resulting from the disposition of temporary measures shall be removed and replaced with suitably compacted soils, or, where applicable, permanently stabilized to prevent further erosion and sedimentation. Maintenance: All erosion and sediment control structures and systems shall be maintained, inspected, and repaired weekly and after each significant rainfall or as needed to insure continued performance of their intended function. Any damage to structural measures shall be repaired immediately. Silt fence shall be inspected after ;very rainfall event and at least daily during prolonged rainfall, as well as at the end of every working day, with any necessary repairs made immediately. Accumulated sediment shall be removed and disposed of as it becomes necessary, or when deposits have accumulated to one-half of the above ground fence height. All undercutting or erosion shall be repaired immediately. the contractor shall follow all manufacturers recommendations for installation, maintenance, replacement, and repair. damages caused by construction traffic or other activity must be repaired before the end of each working day. All seeded areas are to be checked to insure a good stand is maintained. General construction notes for Erosion and Sediment Control plans 1. The plan approving authority must be notified one week prior to the pre -construction conference, one week prior to the commencement of land disturbing activity, and one week prior to the final inspection. 2. All erosion and sediment control measures will be constructed and maintained according to minimum standards and specifications of the Virginia Erosion and Sediment Control Handbook and Virginia Regulations VR 625-02-00 Erosion and Sediment Control Regulations. 3. All erosion and sediment control measures are to be placed prior to or as the first step in clearing. 4. A copy of the approved erosion and sediment control plan shall be maintained on the site at all times. 5. Prior to commencing land disturbing activities in areas other than indicated on these plans (including, but not limited to, off -site borrow or waste areas), the contractor shall submit a supplementary erosion control plan to the owner for review and approval by the plan approving authority. 6. The contractor is responsible for installation of any additional erosion control measures necessary to prevent erosion and sedimentation as determined by the plan approving authority. 7. All disturbed areas are to drain to approved sediment control measures at all times during land disturbing activities and during site development until final stabilization is achieved. 8. During dewatering operations, water will be pumped into an approved filtering device. 9. The contractor shall inspect all erosion control measures periodically and after each runoff producing rainfall event. Any necessary repairs or cleanup to maintain the effectiveness of the erosion control devices shall be made immediately. 10. All fill material to be taken from an approved, designated borrow area. 11. All waste materials shall be taken to an approved waste area. Earth fill shall be inert materials only, free of roots, stumps, wood, rubbish, and other debris. 12. Borrow, fill or waste activity involving industrial -type power equipment shall be limited to the hours of 7:00am to 9:00pm. 13. Borrow, fill or waste activity shall be conducted in a safe manner than maintains lateral support, or order to minimize any hazard to persons, physical damage to adjacent land and improvements, and damage to any public street because o slides, sinking, or collapse. 14. Temporary stabilization shall be temporary seeding and mulching. Seeding is to be at 75lbs/acre, and in the months of September to February to consist a 50/50 mix of Annual Ryegross and Cereal Winter Rye, or in March and April to consist of Annual Rye, or May through August to consist of German Millet. Straw mulch is to be applied at 80lbs/100sf. Alternatives are subject to approved by the erosion control inspector. 15. Permanent stabilization shall be lime and fertilizer, permanent seeding, and mulch. Agricultural grade limestone shall be applied at 90lbs/1000sf, incorporated into the top 4-6 inches of soil. Fertilizer shall be applied at 1000lbs/acre and consist of a 10-20-10 nutrient mix. Permanent seeding shall be applied at 180lbs/acre and consist of 95% Kentucky 31 or Tall Fescue and 0-5% Perennial Ryegrass or Kentucky Bluegrass. Straw mulch is to be applied at 80lbs/100sf. Alternatives are subject to approved by the County erosion control inspector. 16. Maintenance: All measures are to be inspected weekly and after each rainfall. Any damage or clogging to structural measures is to be repair immediately. Silt traps are to be cleaned when 50% of the wet storage volume is filled with sediment. All seeded areas are to be reseeded when necessary to achieve a good stand of grass. Silt fence and diversion dykes which are collecting sediment to half their height must be cleaned and repaired immediately. 17. All temporary erosion and sediment control measures are to be removed within 15 days of final site stabilization, when measures are no longer needed, subject to approval by the County erosion control inspector. 18. Permanent vegetation shall be installed on all denuded areas within nine (9) months after the date the land disturbing activity commenced. MS-1 Permanent or temporary soil stabilization must be applied to denuded areas within seven days after final grade is reached on any portion of the site. Temporary soil stabilization shall be applied within seven days to denuded areas that may not be at final grade but will remain dormant (undisturbed) for longer than 15 days. Permanent stabilization shall be applied to areas that are to be left dormant for more than one year. Soil stabilization refers to measures which protect soil from the erosive forces of raindrop impact and flowing water. Applicable practices include vegetative establishment, mulching, and the early application of gravel base on areas to be paved. Soil stabilization measures should be selected to be appropriate for the time of year, site conditions and estimated duration of use. MS-2 wring construction of the project, soil stockpiles and borrow areas shall be stabilized or protected with sediment trapping measures. The applicant is responsible for the temporary protection and permanent stabilization of all soil stockpiles on site as well as borrow areas and soil intentionally transported from the project site. MS-3 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 achieved that, is uniform, mature enough to survive and will inhibit erosion. ® 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. MS-5 Stabilization measures shall be applied to earthen structures such as dams, dikes, traps, basins and diversions immediately after installation. MS-6 Surface runoff from disturbed areas that is comprised of flow from drainage areas greater than or equal to three acres shall be controlled by a sediment basin. The sediment basin shall be designed and constructed to accommodate the anticipated sediment loading from the land disturbing activity. The outfall device or system design shall take into account the total drainage area flowing through the disturbed area to be served by the basin. MS-7 Cut and fill slopes shall be 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. MS-8 Concentrated runoff shall not flow down cut or fill slopes unless contained within an adequate temporary or permanent channel, flume, or slope drain structure. MS-9 Whenever water seeps from a slope face, adequate drainage or other protection shall be provided. IS�10 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. MS-11 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. MS-12 through 15 - Not applicable, no live watercourses. MS-16 Underground utility lines shall be installed in accordance with the following standards in addition to other applicable 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 from dewatering operations shall be filtered or passed through an approved sediment trapping device, or both, and discharged in a manner that does not adversely affect flowing streams or off -site property. d. Restabilization shall be accomplished in accordance with these regulations. e. Applicable safety regulations shall be complied with. MS-17 Where construction vehicle access routes intersect paved public roads, provisions shall be made to minimize the transport of sediment by vehicular tracking onto the paved surface. Where sediment is transported onto a public road surface, the road shall be cleaned thoroughly every four hours. Sediment shall be removed from the roads by shoveling or sweeping and transported to a sediment control disposal area. Street washing shall be allowed only after sediment is removed in this manner. All temporary erosion and sediment control measures shall be removed within 30 days after final site stabilization or after the temporary measures are no longer needed, unless otherwise authorized by the local program administrator. Trapped sediment and the disturbed soil areas resulting from the disposition of temporary measures shall be permanently stabilized to prevent further erosion and sedimentation. MS-19 The site discharges into Mad Run where it is less than 1 % of the total watershed (9VAC25-870-66 C-3-a) GENERAL EROSION AND SEDIMENT CONTROL NOTES ES-1: UNLESS OTHERWISE INDICATED, ALL VEGETATIVE AND STRUCTURAL EROSION AND SEDIMENT CONTROL PRACTICES WILL BE CONSTRUCTED AND MAINTAINED ACCORDING TO MINIMUM STANDARDS AND SPECIFICATIONS OF THE VIRGINIA EROSION AND SEDIMENT CONTROL HANDBOOK AND VIRGINIA REGULATIONS VR 625-02-00 EROSION AND SEDIMENT CONTROL REGULATIONS. ES-2: THE PLAN APPROVING AUTHORITY MUST BE NOTIFIED ONE WEEK PRIOR TO THE PRE- CONSTRUCTION CONFERENCE, ONE WEEK PRIOR TO THE COMMENCEMENT OF LAND DISTURBING ACTIVITY, AND ONE WEEK PRIOR TO THE FINAL INSPECTION. ES-3: ALL EROSION AND SEDIMENT CONTROL MEASURES ARE TO BE PLACED PRIOR TO OR AS THE FIRST STEP IN CLEARING. ES-4: A COPY OF THE APPROVED EROSION AND SEDIMENT CONTROL PLAN SHALL BE MAINTAINED ON THE SITE AT ALL TIMES. ES-5: PRIOR TO COMMENCING LAND DISTURBING ACTIVITIES IN AREAS OTHER THAN INDICATED ON THESE PLANS (INCLUDING, BUT NOT LIMITED TO, OFF -SITE BORROW OR WASTE AREAS), THE CONTRACTOR SHALL SUBMIT A SUPPLEMENTARY EROSION CONTROL PLAN TO THE OWNER FOR REVIEW AND APPROVAL BY THE FLAN APPROVING AUTHORITY. ES-6: THE CONTRACTOR IS RESPONSIBLE FOR INSTALLATION OF ANY ADDITIONAL EROSION CONTROL MEASURES NECESSARY TO PREVENT EROSION AND SEDIMENTATION AS DETERMINED BY THE PLAN APPROVING AUTHORITY. ES-7: ALL DISTURBED AREAS ARE TO DRAIN TO APPROVED SEDIMENT CONTROL MEASURES AT ALL TIMES DURING LAND DISTURBING ACTIVITIES AND DURING SITE DEVELOPMENT UNTIL FINAL STABILIZATION IS ACHIEVED. ES-8: DURING DEWATERING OPERATIONS, WATER WILL BE PUMPED INTO AN APPROVED FILTERING DEVICE. ES-9: THE CONTRACTOR SHALL INSPECT ALL EROSION CONTROL MEASURES PERIODICALLY AND AFTER EACH RUNOFF -PRODUCING RAINFALL EVENT. ANY NECESSARY REPAIRS OR CLEANUP TO MAINTAIN THE EFFECTIVENESS OF THE EROSION CONTROL DEVICES SHALL BE MADE IMMEDIATELY. THE RLD IS RESPONSIBLE FOR ONGOING MAINTENANCE AND OPERATION OF THE E&SC PLAN. FOR THE PURPOSES OF PLAN SUBMITTAL, REVIEW AND APPROVAL, THE RLD IS B. CLARK GATHRIGHT, P.E. _SE Ql1ENCE OF CONSTRUCTION 1. Install Construction Entrance, Construction Road Stabilization and Silt Fence where shown on the plan. 2. Clear and dispose of trees and vegetation within limits of grading. 3. Execute grading as shown on the plan. 4. Stabilize disturbed areas as directed on plan; crushed stone on travelways, seed and mulch along perimeter and drainfield area. 5. Apply mulching and permanent seeding on permanently stabilized areas that are not affected by site access and grading activities. 6. Remove silt fence after all disturbed areas are stabilized, with approval of County ESC Inspector. OVERALL BOUNDARY SCALE: I" = 1000' DRAINAGE AREAS (PRE & POST SCALE: 1" = 1000' (TOPOGRAPHY SOURCE: COUNTY GIS) E 0 N U o vj N N L Q J z � Ca o g Lc W J cm CCS w U z W 00 U ~ 00 U � cr) _ o = o co U --,r 0p t- OO D C'vARK GATHRIGHT L i c . �jc . fC63,6 3 ' If NAL N tCS E Q 0 z n I— � z — W m W Q L - a3 LU CL cn o � z REVISIONS: 07-30-18 08-01-18 11-12-18 DATE: 07-29-18 DRAWING NUMBER: C-i,64 SHEET 6 OF 7 POST DEVELOPMENT - NO BMP: 1.21 LB/YR REQUIRED Project Name: Mint Springs Maintenance Facility (Leta tnpwtcefls' Date: 11j12j2018 constant values I Linear Devel opment Project? Site Information - -- - - -- - I Post -Development Project (Treatment Volume and Loads) - -�---_ - Enter Total Disturbed Area (acres) rJ.92 ; Check: ' 8MP Design Specifications List: 2013 - Linear project? No • + t Land cover areas entered correctly? ✓ ' Total disturbed area entered? ReDevelopment Land Cover (acres) A Soils B soils C Soils D Soils Totals t/Open 5pace (acres) - undisturbed o en space 0.92 ged Turf (acres) -- disturbed, graded for or other turf to be mowed/managed 0.00 vious Cover(acres) 0,60 O,OD velopment Land Cover (acres) A Soils a lolls C Sells D Soils Totals yen Space (acres) - undisturbed, forest/o en space or reforested land O.DO. fl.oD' Turf (acres) - disturbed, graded for ther turf to be mowed/managed 0.24•�4 s cover (acres) 0.68 aft Stds & Specs- Constants IRunoff Coefficients Rv Annual Rainfall (inches) 43 A Soils B Soils C Soils D Soils Target Rainfall Event (inches) 1.00 Forest/Open Space 0:02 0.03 0.04 D:OS Total Phosphorus (TP) EMC (mg,/L) 0.26 Managed Turf 0.15 0.20 0.22 0.25 Total Nitrogen (TN) EMC (mg/L) _ 1.86 Impervious Cover D.95 __ 0.95 D.95 0.95 Target TP Load (Ib/acreiyr) 0,41 '.. Pj (unitless correction factor) 0.90 Land Cover Summary -Pre Pre-ReDevelopment Listed Forest/Open Space Cover (acres) 0 92' Weighted Rv(forest) Cl % Forest 1Dk: Managed Turf Cover(acres) O.00J Weighted Rv(turt) D.00 % Managed Turf 0%I Impervious Cover (acres) Rv(imperviom) O,gs %Impervious Ogn` Total Site Area (acres) p.gt Site Rsr -•O.Q ; Treatment Volume and Nutrien Pre-ReDevelopment Treatment Volume (acre-£t} Pre-ReDevelopment Treatment Volume (cubic feet) Land Cover Summary -Post (Final) Land CoverSummaryPo Adjusted Post Reoev. & New Impervious Post ReDevelopment 0 Forest/Open Space fl Forest/Open Space r Cover a ras Cover (acres) { f1D3 Weighted Rv(forest) (1,00 . Weighted Rv(forest) 1tK!°rip % Forest .I OQ Managed Turf Cover 024; Mana _�__ ed Turf cover ._.. acres acres i U 0Q Weighted Rv (turf) !, 0.20 Weighted Rv (turf) U% 'A Managed Turf 26% %AAanaged Turf 0 Impervious cover Q 68 Reoev. Impervious (acres) Cover (acres) i iL45 ' Rv(impervious) ,i)35 Rv(impervious) .D% %Impernous 24% %Impervious Final Site Area (acres) r¢,gzJ. Total Reoev. Site Area fl.{ii Final Post Dev Site Rv I 03s: Rellev Site Rv ._. Treatment Volume an Final Post - III Post-Re]evelopment + Development D.078 Treatment Volume Treatment Volume (acre (acre-ft) Final Past- I) Development �( Post-ReDevelopment Treatment Volume .2t51�' Treatment Volume (cubic feet) , Ica blc feet) y Final Post- Post-ReDevelopment Development TP Load 1,SS; * I Load (TP} (lb/yr) [lblYr)° Final Post Develop tTP Load per acre .. v 2 ,ttw+r'; 'i P t R Dev.'.lop lent TP Laad per x�c v (Ib/acrefY) - 77 oy is ?1 _---- (Ib/acre/yr) Max, Reduction R olrM (Below Pre - ReDevelopment Lead) i Adjusted tan€1 Cover Summary: Pre ReDevelopment land cover minus pervious land cover (foresstfopen space or managed turf) acreage proposed for new impervious cover. Adjusted total acreage is consistent with Post-ReDeve(opment acreage {minus acreage of new impervious cover). Column i sho+,vs load reduction requrlement fornew impendaus cover (based on new development toed limit. 0.41 lbs/acre/year). TP Load Reduction Required (lb/yr) 1.21 Post -Development New Impervious New Impervious Cover (acres) -Rv(impervious) rient Load - I Past -Development D.004P I Treatment Volume f 17111} i (acre ft) t ((( 174 d Post -Development "Treatment Volume (cubic h feet} I 6 N Post -Development TIP ( di Ii Load (Ib/yr) 147 ;, TP Load Reduction * Required for Redeveloped Area 0A1. (Ib/yr} *'.Reduction befow new devejppmeni (cod limitation not required Nitrogen Loads (Informational Purposes Only) Final Post-Developmen[TN Loe Pre-ReDevelopment TN Load (lb/yr) 0.45 (Post-ReDevelopment & New Impervious) (lb/yr) 11.32 TP Load Reduction Required for New 1.19 Impervious Area (Ib/yr) 3.75 AC. OPEN SPACE: 1.28 LB/YR PROVIDED Project Name: Mit�%iL-f Date: BMP Design Specifications List: 2013 Draft Stds & Specs Information Post -Development Project (Treatment Volume and loads) Land Cover (acres) ' Forest/Open Space areas most be protected In accordance with the Virginia Runoff Reduction Method irnnctantc Rirnnff fncffiriontc fRvl (Annual Rainfall (inches) 43 Target Rainfall Event inches) 1.00 ,Total Phosphorus (TP) EMC (mg/L) 0.26 !Total Nitrogen (TN) EMC (mg/L) 1.86 Target TP Load (Ib/acre/yr) 0.41 (Pi WrIitless correction factor) 0.90 Land Cover Summary Forest/Open Space Cover (acres) 375 Weighted Rv (forest) 063 % Forest Managed Turf Cover (acres) D:Op Weighted Rv (turf) 0.00 % Managed Turf Q!o Impervious Cover (acres) 0 p0 Rv (impervious) 0 55 % Impervious 096 Site Area (acres) 3.75 Site Rv 0,03 A Soils B Soils C Soils D Soils Forest/open Space 0.02 0.03 0.04 0-05 Managed Turf 0.15 0.2D 0.22 0.25 Impervious Cover 0.95 0.95 0.95 0.95 Treatment Volume and N Treatment Volume (acre-ft) Treatment Volume (cubic feet) TP Load (lb/yr) Loads �atalnpuicells s constant values '-3`75-AG-REMIN._$WM FOhES / ) / / OPEN SPACE EASf Ill NO FUTURE DEVELOP EN# / 1 / WATER QUALITY PLAN - SWM FOREST/OPEN SPA CEEASEMENT SCALE: I" = 100'-0'' E O CV U o (6 0) C_ CV CAI J 70 J o !!7nn V W � J U ter^_ ( V U C� z UJ 00 V ) W U p � �' 1 ,�7rf �Jj �0'7'1 D C AF,! GA 1HRIGHT F- , ✓� � .!err F'G�•.l � LJ E CD L1- 0 0 z a -- c) ©C - 0 U J ccV 00 C) CD CL Cc (� c _ or- < REVISIONS: 07-30-18 08-01-18 11-12-18 DATE: 07-29-18 DRAWING NUMBER: C-1 . SHEET 7 OF 7