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HomeMy WebLinkAboutSW4170401- The Reserve At Regents Center - Phase 2 (2) Permit Number (to be provided by DWQ) NCDENR �®i��� STORMWATER MANAGEMENT PERMIT APPLICATION FORM 401 CERTIFICATION APPLICATION FORM BIORETENTION CELL SUPPLEMENT This form must be filled out,printed and submitted. The Required Items Checklist(Pad Ill)must be printed,filled out and submitted along with all of the required information L PROJECT INFORMATION 1 Project name The Reserve at Regents Center Phase 2 �^ Contact name Thomas R (Rich)Glover,Jr.,PE Phone number (336)886-5523 Date March 21,2017 Drainage area number 1 II. DESIGN INFORMATION _^ _ Site Characteristics — —^ Drainage area 225,976 ft2 Impervious area 114,718 ft2 Percent impervious 50 8% _% Design rainfall depth 1 0 inch Peak Flow Calculations Is pre/post control of the 1-yr,24-hr peak flow required' y (Y or N) 1-yr,24-hr runoff depth 2 86 in 1-yr, Y intensity 0 119 in/hr i,,,tttattr+tnrforr„r Pre-development 1-yr,24-hr peak flow 8.500 ft3/sec "t(tk 9AAC),%*`kQa 0. eao � Post-development 1-yr,24-hr peak flow 13 200 ft3/sec `eE. 0Ip - Pre/Post 1-yr,24-hr peak control 4 700ft3/secg Q�' 'fir mr !'x .r s Storage Volume; Non-SA Waters ,� • -ii a 0 Minimum volume required 9,555.0 ft3 }' Ij� Volume provided 9,607.8 ft3 OK e Storage Volume: SA Waters w .•e'J;�GI>t ��''4 � are w9� e3 1 5”runoff volume ft3 �4R�a.rC'�`C)���a Pre-development 1-yr,24-hr runoff ft3 Post-development 1 yr,24-hr runoff ft3 3 2t I-7 Minimum volume required 0 ft3 (Cl6 Volume provided ft3 Cell Dimensions Pending depth of water 12 inches OK Ponding depth of water 1 00 ft Surface area of the top of the bioretention cell 4,664 0 ft2 OK Length 88 ft OK Width 53 ft OK -or-Radius ft Media and Soils Summary Drawdown time,ponded volume 12 hr OK Drawdown time,to 24 inches below surface 12 hr OK Drawdown time,total 24 hr in-situ soil, Soil permeability 0.20 in/hr Insufficient Increase infiltration rate or include undordrains Planting media soil Soil permeability 0 52 in/hr OK Soil composition Sand(by volume) 85% OK Fines(by volume) _ 10% OK %Organic(by volume) 5% OK Total 100% Phosphorus Index(P-Index)of media 30 (unitless) OK Form SW401-Bioretention-Rev 8 June 25,2010 Parts I and II Design Summary,Page 1 of 2 • Permit Number (to be provided by DWQ) Basin Elevations Temporary pool elevation 669 81 fmsl Type of bioretention cell(answer"Y"to only one of the two following questions) Is this a grassed cell? y (Y or N) OK Is this a cell with trees/shrubs' n (Y or N) Planting elevation(top of the mulch or grass sod layer) 668 81 fmsl Depth of mulch 0 inches Insufficient mulch depth,unless installing grassed cell Bottom of the planting media soil 666.81 fmsl Planting media depth 2 ft Depth of washed sand below planting media soil 0.33 ft Are underdrains being installed'? y (Y or N) How many clean out pipes are being installed'? 9 OK What factor of safety is used for sizing the underdrains?(See 4 OK BMP Manual Section 12.3.6) Additional distance between the bottom of the planting media and 1 ft the bottom of the cell to account for underdrains Bottom of the cell required 665 48 fmsl SHWT elevation 661 fmsl Distance from bottom to SHWT 4 48 ft OK Internal Water Storage Zone(IWS) Does the design include IWS n (Y or N) Elevation of the top of the upturned elbow 0 fmsl Separation of IWS and Surface 668.81 ft OK Planting Plan Number of tree species 0 Number of shrub species Number of herbaceous groundcover species Additional Information Does volume in excess of the design volume bypass the Y (Y or N) OK bioretention cell'? Does volume in excess of the design volume flow evenly distributed Y (Y or N) OK through a vegetated filter? What is the length of the vegetated filter? ft Does the design use a level spreader to evenly distribute flow'? N (Y or N) Show how flow is evenly distributed Is the BMP located at least 30 feet from surface waters(50 feet if Y (Y or N) OK SA waters)? Is the BMP located at least 100 feet from water supply wells? Y (Y or N) OK Are the vegetated side slopes equal to or less than 3 1'? Y (Y or N) OK Is the BMP located in a proposed drainage easement with access Y (Y or N) OK to a public Right of Way(ROW)' Inlet velocity(from treatment system) 9 1 ft/sec Insufficient inlet velocity unless energy dissipating devices aro being used. Is the area surrounding the cell likely to undergo development in N (Y or N) OK the future'? Are the slopes draining to the bioretention cell greater than 20%2 N (Y or N) OK Is the drainage area permanently stabilized'? Y (Y or N) OK Pretreatment Used (Indicate Type Used with an"X"in the shaded cell) Gravel and grass (flinches gravel followed by 3-5 ft of grass) Grassed swale OK Forebay X Other Form SW401-Bioretention-Rev 8 June 25,2010 Parts I and II Design Summary,Page 2 of 2 Permit Number________ (to be provided by DWQ) ' Cl `_. NCDENR STORMWATER MANAGEMENT PERMIT APPLICATION FORM 401 CERTIFICATION APPLICATION FORM BIORETENTION CELL SUPPLEMENT This form must be filled out,printed and submitted. The Required Items Checklist(Part III)must be printed, filled out and submitted along with all of the required information. 1. PROJECT INFORMATION — Project name The Reserve at Regents Center Phase 2 Contact name Thomas R (Rich)Glover,Jr.,PE 4 Phone number (336)886-5523 Date March 21,2017 Drainage area number 2 II. DESIGN INFORMATION _ Site Characteristics Drainage area 56,628 ft2 Impervious area 39,419 ft2 Percent impervious 69 6% % Design rainfall depth 1 0 inch Peak Flow Calculations �{�i�f10P Is pre/post control of the 1-yr,24-hr peak flow required? y (Y or N) 1-yr,24-hr runoff depth 2.86 in �� ,! 1-yr,24-hr intensity 0,119 in/hr _g,`�•$F ��� f ,�( 'P Pre-development 1-yr,24-hr peak flow 1.860 ft/sec •et t: '� Post-development 1-yr,24-hr peak flow 2.940 ft3/sec . •I 2 Pre/Post 1-yr,24-hr peak control 1.080 ft3/sec Storage Volume: Non-SA Waters • � , t�> Minimum volume required • c• i 3 .�� q 3,192.0 ft3 .� Volume provided 3,2301 ft3 OK '� aitste Storage Volume: SA Waters j t‘ 1 5"runoff volume ft3 Pre-development 1-yr,24-hr runoff ft3 Post-development 1-yr,24-hr runoff ft3 Minimum volume required 0 ft3 Volume provided ft3 Cell Dimensions Ponding depth of water 12 inches OK Ponding depth of water 1.00 ft Surface area of the top of the bioretention cell 1,568.0 ft2 OK Length. 56 ft OK Width. 28 ft OK -or-Radius ft Media and Soils Summary Drawdown time,ponded volume 12 hr OK Drawdown time,to 24 inches below surface 12 hr OK Drawdown time,total 24 hr In-situ soil Soil permeability 0 20 in/hr Insufficient Increase infiltration rate or include underdrains Planting media soil Soil permeability 0 52 in/hr OK Soil composition Sand(by volume) 85% OK Fines(by volume) _ 10% OK %Organic(by volume) 5% OK Total 100% Phosphorus Index(P-Index)of media 30 (unitless) OK Form SW401-Bioretention-Rev 8 June 25,2010 Parts I and II Design Summary,Page 1 of 2 + r Permit Number (to be provided by DWQ) Basin Elevations Temporary pool elevation 66311 fmsl Type of bioretention cell(answer"Y"to only one of the two following questions), Is this a grassed cell? y (Y or N) OK Is this a cell with trees/shrubs? n (Y or N) Planting elevation(top of the mulch or grass sod layer) 662.11 fmsl Depth of mulch 0 inches Insufficient mulch depth,unless installing grassed cell Bottom of the planting media soil 660.11 fmsl Planting media depth 2 ft Depth of washed sand below planting media soil 0 33 ft Are underdrains being installed? y (Y or N) How many clean out pipes are being installed? 2 OK What factor of safety is used for sizing the underdrains?(See 4 OK BMP Manual Section 12 3.6) Additional distance between the bottom of the planting media and 1 ft the bottom of the cell to account for underdrains Bottom of the cell required 658 78 fmsl SHWT elevation 656 fmsl Distance from bottom to SHWT 2.78 ft OK Internal Water Storage Zone(IWS) Does the design include IWS n (Y or N) Elevation of the top of the upturned elbow 0 fmsl Separation of IWS and Surface 662 11 ft OK Planting Plan Number of tree species 0 Number of shrub species 0 Number of herbaceous groundcover species Additional Information Does volume in excess of the design volume bypass the Y (Y or N) OK bioretention cell? Does volume in excess of the design volume flow evenly distributed Y (Y or N) OK through a vegetated filter? What is the length of the vegetated filter? ft Does the design use a level spreader to evenly distribute flow? N (Y or N) Show how flow is evenly distributed Is the BMP located at least 30 feet from surface waters(50 feet if SA waters)? Y (Y or N) OK Is the BMP localed at least 100 feet from water supply wells? Y (Y or N) OK Are the vegetated side slopes equal to or less than 3 1? Y (Y or N) OK Is the BMP located in a proposed drainage easement with access to a public Right of Way(ROW)? Y (Y or N) OK Inlet velocity(from treatment system) 7 ft/sec Insufficient inlet velocity unless energy dissipating devices are being used Is the area surrounding the cell likely to undergo development in the future? N (Y or N) OK Are the slopes draining to the bioretention cell greater than 20%7 N (Y or N) OK Is the drainage area permanently stabilized? Y (Y or N) OK Pretreatment Used (Indicate Type Used with an"X"in the shaded cell) Gravel and grass (flinches gravel followed by 3-5 ft of grass) Grassed swale OK Forebay X Other Form SW401-Bioretention-Rev 8 June 25,2010 Parts I and II Design Summary,Page 2 of 2 Permit Number: (to be provided by DWQ) Drainage Area Number: I Bioretention Operation and Maintenance Agreement I will keep a maintenance record on this BMP. This maintenance record will be kept in a log in a known set location. Any deficient BMP elements noted in the inspection will be corrected, repaired or replaced immediately. These deficiencies can affect the integrity of structures, safety of the public, and the removal efficiency of the BMP. Important operation and maintenance procedures: - Immediately after the bioretention cell is established, the plants will be watered twice weekly if needed until the plants become established (commonly six weeks). - Snow, mulch or any other material will NEVER be piled on the surface of the bioretention cell. - Heavy equipment will NEVER be driven over the bioretention cell. - Special care will be taken to prevent sediment from entering the bioretention cell. - Once a year, a soil test of the soil media will be conducted. After the bioretention cell is established, I will inspect it once a month and within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a Coastal County). Records of operation and maintenance will be kept in a known set location and will be available upon request. Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately. BMP element: Potential problems: How I will remediate the problem: The entire BMP Trash/debris is present. Remove the trash/debris. The perimeter of the Areas of bare soil and/or Regrade the soil if necessary to bioretention cell erosive gullies have formed. remove the gully,and then plant a ground cover and water until it is established. Provide lime and a one-time fertilizer application. The inlet device: pipe, The pipe is clogged (if Unclog the pipe. Dispose of the /; stone verge or swale applicable). sediment off-site. The pipe is cracked or Replace the pipe. / otherwise damaged (if applicable). Erosion is occurring in the Regrade the swale if necessary to swale (if applicable). smooth it over and provide erosion control devices such as reinforced turf matting or riprap to avoid future problems with erosion. Stone verge is clogged or Remove sediment and clogged covered in sediment(if stone and replace with clean stone. /' applicable). i Form SW401-Bioretention O&M-Rev.3 Page; BMP element: Potential problems: How I will remediate the problem: The pretreatment area Flow is bypassing Regrade if necessary to route all pretreatment area and/or flow to the pretreatment area. gullies have formed. Restabilize the area after grading. Sediment has accumulated to Search for the source of the a depth greater than three sediment and remedy the problem if inches. possible. Remove the sediment and restabilize the pretreatment area. Erosion has occurred. Provide additional erosion protection such as reinforced turf matting or riprap if needed to prevent future erosion problems. Weeds are present. Remove the weeds, preferably by hand. The bioretention cell: Best professional practices Prune according to best professional vegetation show that pruning is needed practices. to maintain optimal plant health. Plants are dead, diseased or Determine the source of the dying. problem: soils,hydrology,disease, etc. Remedy the problem and replace plants. Provide a one-time fertilizer application to establish the ground cover if a soil test indicates it is necessary. Tree stakes/wires are present Remove tree stake/wires (which six months after planting. can kill the tree if not removed). The bioretention cell: Mulch is breaking down or Spot mulch if there are only random soils and mulch has floated away. void areas. Replace whole mulch layer if necessary. Remove the remaining much and replace with triple shredded hard wood mulch at a maximum depth of three inches. Soils and/or mulch are Determine the extent of the clogging clogged with sediment. -remove and replace either just the top layers or the entire media as needed. Dispose of the spoil in an appropriate off-site location. Use triple shredded hard wood mulch at a maximum depth of three inches. Search for the source of the sediment and remedy the problem if possible. An annual soil test shows that Dolomitic lime shall be applied as pH has dropped or heavy recommended per the soil test and metals have accumulated in toxic soils shall be removed, the soil media. disposed of properly and replaced with new planting media. Form SW40 I-Bioretention O&M-Rev.3 Page 2 of 4 BMP element: Potential problems: How I will remediate the problem: The underdrain system Clogging has occurred. Wash out the underdrain system. (if applicable) The drop inlet Clogging has occurred. Clean out the drop inlet. Dispose of the sediment off-site. The drop inlet is damaged Repair or replace the drop inlet. The receiving water Erosion or other signs of Contact the NC Division of Water damage have occurred at the Quality 401 Oversight Unit at 919- outlet. 733-1786. Form SW40I-Bioretention O&M-Rev.3 Page 3 of 4 Permit Number: (to be provided by DIVA) I acknowledge and agree by my signature below that I am responsible for the performance of the maintenance procedures listed above. I agree to notify DWQ of any problems with the system or prior to any changes to the system or responsible party. Project name: THE RESERVE AT REGENTS CENTER - PHASE 2 BMP drainage area number:1 Print name: (-&Vwri E. Ratkfrd J . Title: ?reSida+ Address:165 SOUTH YORK STREET GASTONINA NC 28054 Phone:704-869-6024 Signature: Date: 3 la a&i 7 Note: The legally responsible party should not be a homeowners association unless more than 50%of the lots have been sold and a resident of the subdivision has been named the president. I, . Arevia F, Shad a , a Notary Public for the State of Ner-+Gi Carolina , County of C3;5 , do hereby certify that 14e,rtt1`Z.fl &d j-f, personally appeared before me this eV day of Ylarth , tia , and acknowledge the due execution of the forgoing bioretention maintenance requirements. Witness my hand and official seal. \\\\\,.a� 11F1111�/ f�/! vr7 c� NOTARY PUBLIC ///yN CO\ \\\\\\\\\\� o/i//111111 f 1{m0 SEAL My commission expires Janitor/4 a1i aLg Form SW401-Bioretention l&M-Rev.2 Page 4 of 4 Permit Number: (to be provided by DWQ) Drainage Area Number: 2 Bioretention Operation and Maintenance Agreement I will keep a maintenance record on this BMP. This maintenance record will be kept in a log in a known set location. Any deficient BMP elements noted in the inspection will be corrected, repaired or replaced immediately. These deficiencies can affect the integrity of structures,safety of the public, and the removal efficiency of the BMP. Important operation and maintenance procedures: - Immediately after the bioretention cell is established, the plants will be watered twice weekly if needed until the plants become established (commonly six weeks). - Snow, mulch or any other material will NEVER be piled on the surface of the bioretention cell. - Heavy equipment will NEVER be driven over the bioretention cell. - Special care will be taken to prevent sediment from entering the bioretention cell. - Once a year, a soil test of the soil media will be conducted. After the bioretention cell is established, I will inspect it once a month and within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a Coastal County). Records of operation and maintenance will be kept in a known set location and will be available upon request. Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately. BMP element: Potential problems: How I will remediate the problem: The entire BMP Trash/debris is present. Remove the trash/debris. The perimeter of the Areas of bare soil and/or Regrade the soil if necessary to bioretention cell erosive gullies have formed. remove the gully,and then plant a ground cover and water until it is established. Provide lime and a one-time fertilizer application. The inlet device: pipe, The pipe is clogged (if Unclog the pipe. Dispose of the stone verge or swale applicable). sediment off-site. The pipe is cracked or Replace the pipe. otherwise damaged (if applicable). Erosion is occurring in the Regrade the swale if necessary to swale (if applicable). smooth it over and provide erosion control devices such as reinforced turf matting or riprap to avoid future problems with erosion. _ Stone verge is clogged or Remove sediment and clogged covered in sediment(if stone and replace with clean stone. applicable). Form SW40I-Bioretention O&M-Rev.3 Page 1 of 4 BMP element: Potential problems: How I will remediate the problem: The pretreatment area Flow is bypassing Regrade if necessary to route all pretreatment area and/or flow to the pretreatment area. gullies have formed. Restabilize the area after grading. Sediment has accumulated to Search for the source of the a depth greater than three sediment and remedy the problem if inches. possible. Remove the sediment and restabilize the pretreatment area. Erosion has occurred. Provide additional erosion protection such as reinforced turf matting or riprap if needed to prevent future erosion problems. Weeds are present. Remove the weeds, preferably by hand. _ The bioretention cell: Best professional practices Prune according to best professional vegetation show that pruning is needed practices. to maintain optimal plant health. Plants are dead, diseased or Determine the source of the dying. problem: soils, hydrology,disease, etc. Remedy the problem and replace plants. Provide a one-time fertilizer application to establish the ground cover if a soil test indicates it is necessary. Tree stakes/wires are present Remove tree stake/wires (which six months after planting. can kill the tree if not removed). The bioretention cell: Mulch is breaking down or Spot mulch if there are only random soils and mulch has floated away. void areas. Replace whole mulch layer if necessary. Remove the remaining much and replace with triple shredded hard wood mulch at a maximum depth of three inches. Soils and/or mulch are Determine the extent of the clogging clogged with sediment. -remove and replace either just the top layers or the entire media as needed. Dispose of the spoil in an appropriate off-site location. Use triple shredded hard wood mulch at a maximum depth of three inches. Search for the source of the sediment and remedy the problem if possible. An annual soil test shows that Dolomitic lime shall be applied as pH has dropped or heavy recommended per the soil test and metals have accumulated in toxic soils shall be removed, the soil media. disposed of-properly and replaced with new planting media. Form SW401-Bioretention O&M-Rev.3 Page 2 of 4 BMP element: Potential problems: How I will remediate the problem: The underdrain system Clogging has occurred. Wash out the underdrain system. (if applicable) The drop inlet Clogging has occurred. Clean out the drop inlet. Dispose of the sediment off-site. The drop inlet is damaged Repair or replace the drop inlet. The receiving water Erosion or other signs of Contact the NC Division of Water damage have occurred at the Quality 401 Oversight Unit at 919- outlet. 733-1786. Form SW401-Bioretention O&M-Rev.3 Page 3 of 4 Permit Number: (to be provided by DWQ) I acknowledge and agree by my signature below that I am responsible for the performance of the maintenance procedures listed above. I agree to notify DWQ of any problems with the system or prior to any changes to the system or responsible party. Project name: THE RESERVE AT REGENTS CENTER - PHASE 2 BMP drainage area number:2 Print name: AT r----garcb Hrrrnan E. fK - - d, l- Title: Pre5matit Address:165 SOUTH YORK STREET GASTONINA NC 28054 Phone:704-869-6024 Signature: -L � Date: 3/All Ab 17 Note: The legally responsible party should not be a homeowners association unless more than 50%of the lots have been sold and a resident of the subdivision has been named the president. I, ITTIA F 5hu.da , a Notary Public for the State of 1 r+i ezatIX , County of 61,5frytia , do hereby certify that PevviA SIR E Talit,fricri, ar-- personally appeared before me this day of Agra , o 0/7 , and acknowledge the due execution of the forgoing bioretention maintenance requirements. Witness my hand and official seal, r NOVRI pUBLIC ///'TON cov,,\�\`\`, //$IIIIIIItth\ �\; SEAL My commission expires �016 an_�_ Form SW401-Bioretention l&M-Rev.2 Page 4 of 4 Stormwater Treatment & Management Narrative The Reserve at Regents Center Phase 2 March, 2017 The Reserve at Regents Center is an apartment complex that was constructed around 2003. The complex is located on Regents Center Court in Lexington, NC. At the time of the original development, no post-construction stormwater controls were required. Since this time, the City of Lexington has adopted the NPDES Phase II regulations. Southwood Realty Company purchased the existing apartment complex in April of 2015 as well as three undeveloped lots to the northeast of the complex in March of 2017. Their plans are to add four additional apartment buildings as indicated on the enclosed plans by Jamestown Engineering Group, Inc. Construction of the new apartments will take place on high ground that has been previously graded. No impacts to streams or wetlands will be necessary. An erosion control plan has been filed with NCDEQ which indicates the measures that shall be in place to help prevent any off-site sedimentation during the construction activities. A copy of this plan is also included in this submittal. Drainage from the existing apartment complex flows into a 42" storm drainage trunk-line that also captures runoff from US Hwy 52. The 42" pipe discharges at the base of a fill slope where the flow then travels across approximately 480' of floodplain where it then flows into Swearing Creek (12-113 Class C). Drainage from the three undeveloped lots flow into a storm drainage system within the right-of-way of Regents Center Court, which then also discharges into the flood plain of Swearing Creek. In order to treat the runoff from the new building that is being added to the existing complex, the runoff will be routed through a bio-retention cell. The cell will then discharge near the end of the existing 42" trunk-line. The runoff from the three new buildings on the undeveloped lots will be also be treated with a bio-retention cell. That cell will then discharge into the existing storm drainage network within the Regents Center Court right-of-way. Sediment basins and other erosion control devises will remain in place until site stabilization has occurred. Once the site is stabilized, the erosion control devises will be removed and the bio-retention cells will be installed. Southwood Realty Company will continue to be the owner of these properties following construction. As such, Southwood Realty Company will be responsible for the on-going operations and maintenance of the stormwater control devises. Get Maps I topoView https://ngmdb.usgs.gov/maps/topoview/viewer/#14/35.7923/-80.2428 2009 - -- -- -- - 2010 - --- y,eti;''\S' F-'; -rte=_ i Irv: v‘ Cr) N ;iui il,d 0.• 4. �3\\\ , Lexinlgton • T' Medical Cerner 4 i i1'. I \ ':.c Ihig=tof �31c) 0\6 '. 1'aonicljir �a a o 0 Br Op rriSt r1_, -',-i,FE 85 - - - -- --= - OOafl i ' -y G\6"1\ i2U cl -- , - -'` I'Tlhoma:. .„..,-,,,,„:„ _ Imo ni, rtm?� MAP RECORDS:0 �` • ..oft ,,Y, , ' / . Leaflet©Mapbox©OpenStreetMap LaR:3$'$3'14"!N Lonc S0'1W'12"W - „,/c,,, N�'- 1 of 1 3/30/2017 11:12 AM