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Home My WebLink About20170127_Horsepen Creek Road in Greensboro with Attachment_20160830Wrenn, Brian L From: Sent: To: Subject: Attachments: Follow Up Flag: Flag Status: Jamison, John R. <John.Jamison@hdrinc.com> Tuesday, August 30, 2016 11:33 AM Wrenn, Brian L Horsepen Creek Road in Greensboro Horsepen HYD_SMPv2.06_(20160824).pdf Follow up Completed Brian — Attached is the SMP in the DOT format for the Horsepen Creek Road project, for your cursory review that you offered me the other day. Jessica Tisdale sent you some draft permit impact sheets back in June. Let me know if you want a full set of roadway drawings to go along with this SMP. Thank you! � Il � i��119 I'sVVS z�nfar �nvfrr�nrn�;ntal zaaf�;ntfst I�N I� I� 555 F�ye;��e;v�llll� ��re;e;� �uii�e; �(7(7 f��ll�xc�r7,l`�C 2IC�(71 � �1�.232.C�C�25 Nl �1�.£;(71.£;�I1 �Vaar7r7.�V�rmasaar7(ci�r7¢�r�r7c.caarm r7a�riir7c.czarmlfzallllzaw-us Hi�;hW�ly North Carolina Department of Transportation � Stormw�ter I � ,,,,�,,,,,, Highway Stormwater Program �3J STORMWATER MANAGEMENT PLAN -- (Version 2.06; Released June 2016) FOR NCDOT PROJECTS WBS Element: TIP No.: Horsepen Creek Road County(ies): Guilford Page 1 of 3 General Project Information WBS Element: TIP Number: Horsepen Creek Road Project Type: Roadway Widening Date: 8/24/2016 NCDOT Contact: City of Greensboro - Mr. Gu In le, Project En ineer Contractor / Designer: HDR Engineerin Inc., of the Carolinas Michelle Podeszwa, PE) Address: Engineering Division Address: 555 Fayetteville St., Suite 900 300 W. Washington Street Raleigh, NC 27601 Greensboro, NC 27401 Phone: 336-373-2302 Phone: 919-232-6600 Email: Gu .In le reensboro-nc. ov Email: Michelle.Podeszwa hdrinc.com Cit ITown: Greensboro Count ies : Guilford River Basin s: Ca e Fear CAMA County? No Wetlands within Project Limits? Yes Pro'ect Description Pro'ect Len th lin. miles or feet : 3.2 miles Surroundin Land Use: suburban residential and commercial development Proposed Pro'ect Existin Site Pro'ect Built-Upon Area ac. -38 ac. -20 ac. Typical Cross Section Description: four-lane, mostly median-divided roadway, urban curb and gutter with bike lanes and two-lane suburban roadway with a graded shoulder, with intermittent sidewalks and sidewalks curb and gutter at more recent residential and commercial developments Annual Avg Daily Traffic (veh/hr/day): Design/Future: u to 24,000 Year: 2035 Existin : 10,000-19,000 Year: 2013 General Project Narrative: The purpose of this project is to improve approximately 3.2 miles of Horse Pen Creek Road between New Garden Road and Battleground Avenue in the City of Greensboro, (Description of Minimization of Water NC. The project includes multilane widening, bicycle lanes, sidewalks on both sides, medians, a bridge over Horse Pen Creek, and realignment where necessary to meet design Quality Impacts) standards. Existing drainage consists of curb inlets, drop inlets, and ditches along Horse Pen Creek Road and the adjacent side roads. Drop inlets and open-end pipes collect runoff from offsite. Reinforced concrete pipes convey existing roadway drainage and offsite runoff. An existing quadruple 12'x10' reinforced concrete box culvert (Structure No. 400101) conveys the flow of Horse Pen Creek under Horse Pen Creek Road. This structure is to be replaced with a bridge over Horse Pen Creek. Stormwater BMP's and water quality enhancements were incorporated wherever feasible in order to retrofit water quality benefits into the existing roadway corridor. The urban nature of the corridor limited the designer's ability to introduce BMP's to treat stormwater outlets in places. The proposed storm drainage system will be curb and gutter and will include curb inlets and drop inlets to collect roadway runoff. Existing inlets and pipes are being retained and connected into the proposed drainage system wherever possible. Runoff is conveyed through RCP and HDPE pipes to proposed outfalls. All proposed drainage systems maintain existing flow patterns and outfalls. A pre/post analysis was performed for all outfalls to determine off-site impacts due to increased stormwater runoff. There were no post-discharge increases above 10% except for outfalls at Quaker Run Drive (Sta. 12+32 RT) and Horse Pen Creek Road (Sta. 181+58 LT). The increase at Quaker Run Drive is due to the disturbed area being 36% of the total area studied since the downstream watershed is limited by Horse Pen Creek. The outfall is proposed to discharge into a dry detention basin for water quality treatment. The increase at Horse Pen Creek Road Sta. 181+58 LT is due to the disturbed area being 20% of the total drainage area studied since the downstream watershed is limited by an existing wet pond. The outfall is proposed to discharge into a dry detention basin that will reduce the post discharge from 5.8 cfs to 2.8 cfs for the 10 year storm event. Detailed calculations for the pre/post analysis were reviewed by City water resources staff. Waterbody Information Surface Water Body (1): Horsepen Creek NCDWR Stream Index No.: 16-11-5-(0.5) NCDWR Surface Water Classification for Water Body Primary Classification: Water Supply III (WS-III) Supplemental Classification: Nutrient Sensitive Waters (NSW) Other Stream Classification: Impairments: biological impairment Aquatic T&E Species? No Comments: 2014 303(d): Benthos Poor (Nar, AL, FW ) since 2000 NRTR Stream ID: Buffer Rules in Effect: Jordan Lake Project Includes Bridge Spanning Water Body? Yes Deck Drains Discharge Over Buffer? No Dissipator Pads Provided in Buffer? N/A Deck Drains Discharge Over Water Body? No (If yes, provide justification in the General Project Narrative) (If yes, describe in the General Project Narrative; if no, justify in the (If yes, provide justification in the General Project Narrative) General Project Narrative) Hi�hw�y North Carolina Department of Transportation \ Stormwater I� � , H ig hway Stormwater Program .J� �;% STORMWATER MANAGEMENT PLAN (Version 2.06; Released June 2016) FOR NCDOT PROJECTS WBS Element: TIP No.: Horsepen Creek Road County(ies): Guilford Page 2 of 3 Additional Waterbod Information Surface Water Bod 2: Brush Creek / Lake Hi ins NCDWR Stream Index No.: 16-11-4-(1 NCDWR Sufface Water Classification for Water Body Primar Classification: Water Su I III WS-III Supplemental Classification: Nutrient Sensitive Waters (NSW Other Stream Classification: Impairments: None Aquatic T8E Species? No Comments: NRTR Stream ID: Buffer Rules in Effect: Jordan Lake Pro'ect Includes Brid e Spannin Water Bod ? No Deck Drains Discharge Over Buffer? N/A Dissipator Pads Provided in Buffer? N/A Deck Drains Dischar e Over Water Bod ? N/A (If yes, provide justification in the General Project Narrative) (If yes, describe in the General Project Narrative; if no, justify in the (If yes, provide justification in the General Project Narrative) General Project Narrative) Surface Water Body (3 : Reedy Fork Lake Brandt & Lake Townsend) NCDWR Stream Index No.: 16-11-(3.5)a NCDWR Surface Water Classification for Water Body Primary Classification: Water Supply III WS-III Supplemental Classification: Nutrient Sensitive Waters NSW Other Stream Classification: Impairments: None Aquatic T8E Species? No Comments: NRTR Stream ID: Buffer Rules in Effect: Jordan Lake Project Includes Bridge Spanning Water Body? No Deck Drains Discharge Over Buffer? N/A Dissipator Pads Provided in Buffer? N/A Deck Drains Dischar e Over Water Bod ? N/A (If yes, provide justification in the General Project Narrative) (If yes, describe in the General Project Narrative; if no, justify in the (If yes, provide justification in the General Project Narrative) General Project Narrative) Hi�riway Stormwater ersion 2.06; Released June WBS Element: eet No. G2 C-4 C-8 G12 G16 Station & Coordinates id and Non Road Proje -L- 30+06 LT -L- 49+z0 RT -L- 89+00 LT -L- 131+97 LT -L- 181+21 LT Surface Water Boc Brandt & TIP No.: North Carolina Department of Transportation Highway Stormwater Program STORMWATER MANAGEMENT PLAN FOR NCDOT PROJECTS n Creek Road County(ies Other Best Management Practices New Built-Upon Drainage Area Area BMP Type ac ac Dry Detention Basin 3.6 1.4 Stormceptor 6.5 2.0 Bioretention Basin 2.6 0.6 Dry Detention Basin 7.6 0.7 Dry Detention Basin 2.0 0.4 Guilford Volume Treated (ac-ft) 0.23 0.034 0.1146 0.191 0.067 -�;j Page 3 of 3 Precipitation Depth Treated over NBUA BMP Associated (in) w/ Buffer Rules? 2.12 0.22 2.26 3.30 2.11 Additional Comments ie outlet at 30+06 LT is adjacent to a roadside ditch which turns into a jurisdictional stream approximately 500' farther downstream. The outlet of the stormwater system cannot be raised enough to outlet to a bioretention cell because of existing >es and sag points in the system. An excavation and backfill operation would require the underdrains to be set below of elevation of the adjacent ditch which would then require over 100 feet of additional easement to be purchased to place a pipe an adjacent parcel. Due to these constraints a dry detention basin was proposed at this outlet which achieves a 50% TSS removal. ie outlet at 45+50 RT is adjacent to a wetland which is adjacent to Horse Pen Creek. The steep grade and wetland limits the size of a BMP, making it insignificant in terms of treating runoff. Impacting the wetland in order to accommodate a ger BMP would have a negative effect on water quality. Due to these constraints, there was no BMP suggested at this outlet. he outlet at 49+20 RT is adjacent to Horse Pen Creek. The floodway of Horse Pen Creek and the greenway access off of Quaker Run Dr. are significant constraints in this area. In order to have the storage area necessary, as well as the change i elevation for the drainage structures to work properly, an earthen berm would need to be constructed which adds to the area needed for the basin. If it were built above grade, a dry detention basin in this area would be less than a third of the size eeded to properly treat the inflow. The catchment for this outlet is greater than 10 acres and therefore a bioretention cell would not be recommended. Due to these constraints, a proprietary system (Stormceptor) was designed to achieve a �duction of TSS. he outlet at 89+00 LT is upgradient of an intermittent stream. It is necessary to excavate and backfill to build a bioretention basin, since the outlet pipe invert cannot be raised due to constraints in the system. Based on soil borings in the area, the easonally high water table would be well below two feet from the bottom of the bioretention cell. Even though additional easement would be needed to lay the outlet pipe of the bioretention cell in order to provide enough fall for the underdrains, the verall footprint for a bioretention cell would be less than what would be required for a dry detention basin. Because of this and the increased water quality benefits, a bioretention cell was proposed at this outlet.The bioretention basin at 89+00 LT tilizes a drain pipe that outlets at the top (ephemeral/intermittent break) of a stream channel in order to minimize future erosion. The existing channel has a fairly severe headcut that would likely work upgradient if the basin were to outlet farther pgradient. During a site visit the Corps representative encouraged this outlet location to help minimize future erosion. he outlet at 110+50 RT is part of an existing cross pipe which outlets as a jurisdictional stream. Additional ROW or easement would be required to build a BMP for this outlet. Also, the topography in this area is very steep and because of that the utlet is at a very low elevation. This would require the BMP to be built within the buffer area and would cause additional permanent impacts to the stream. Due to these constraints, no BMP was proposed for this area. t the outlet at 131+g7 LT, the catchment is greater than 5 acres and therefore it is not recommended that a bioretention cell be used as a BMP. A dry detention basin of adequate size was instead proposed at this outlet. he outlet at 158+7g LT feeds into an ephemeral channel soon after it is discharged. With the additional constraint of numerous nearby homes, a BMP of significant size would not fit. Due to this, no BMP was suggested for this area. o the north of the outlet at 181+z1 LT is an existing wet detention pond built during a previous development. It was assumed that it was designed to treat the stormwater from most of this area for quantity and quality. Due to this, a small detention asin was proposed for this area to mitigate the peak flow for pre- versus post-development.