Loading...
HomeMy WebLinkAbout20130705 Ver 1_Barnes Noble (Cary Commons) BMP #667_2013061720130705 EEP NUTRIENT OFFSET PROJECT SUMMARY Cary Commons (aka, Barnes & Noble) BMP Extended Detention Stormwater Wetland EEP #667 Synopsis r-'j, Agmre-m 'Milt tOpRwY EEP's Cary Commons BMP site (EEP #667) is an extended detention stormwater wetland BMP located in Cary, North Carolina within the Neuse River basin CU 03020201. The project was initiated by NCEEP to offset nutrient loading as a third -party credit provider in the Neuse River basin (15A NCAC 02B.0240). The project design was designed by the NC State Department of Biological and Agricultural Engineering and involved retrofitting and expanding an existing wet detention BMP into an extended detention wetland BMP. Final construction and planting was completed in August 2011. The Town of Cary is currently maintaining the site per the BMP maintenance agreement with the State of NC, which extends for a 30 -year period. The stormwater wetland is designed to remove 214.16 lbs /year of nitrogen, generating a 30 -year credit value of 6439.2 lbs reduction of Total Nitrogen. Additionally, the project is designed to reduce 534.91bs of total phosphorous (TP) over 30 years; however, TP reduction credit is not available in the Neuse River basin. Site Location River Basin: CU: 14 -digit HUC: County: Municipality: Receiving Waters: Use Support Rating: Project History Neuse 03020201 03- 020201 - 1100 -10 Wake JUiV 1 i 2013 Cary NC UT to Lynn Branch (Meadows Crk); 27 -43 -3; 03 -04 -02 Lynn Branch = Not Rated Memo of Agreement Signed: Final Design: Construction Completed: Planting Completed: As- Builts Submitted to DWQ: May 26, 2006 January 2010 July 2011 July 2011 August 2011 1 Project Participants Source Agency: NC Ecosystem Enhancement Program Project Management: NC Ecosystem Enhancement Program Designer: NC State (Dept of Biological & Agricultural Engineering) Construction: Hine Sitework Inc.Construction Landowner: Town of Cary NC BMP Management: Town of Cary NC BMP Design Parameters BMP Type: Watershed Area: Watershed Description: Percent Impervious: BMP Storage Volume: Max Storm Depth Caph Extended Detention Stormwater Wetland 46.3 acres Commercial development, shopping centers, parking lots, roadways 68% 31,590 cubic feet fired: 0.8 in rain event Nutrient Removal (TN = Total Nitrogen; TP = Total Phosphorous) Pre -BMP TN Loading: Post -BMP TN Loading 30 -yr TN Removal: Pre -BMP TP Loading: Post -BMP TP Loading: 30 -yr TP Removal: 596.22 lbs /yr (12.9 lbs /ac /yr) 381.58 lbs /yr (8.24 lbs /ac /yr) 6439.2 lbs (214.64 lbs /yr) 55.72 lbs /yr (1.2 lbs /ac /yr) 37.89 lbs /yr (0.82 lbs /ac /yr) 534.9 lbs (11.55 lbs /yr) Property Protection & Maintenance Property Protection Method: State of NC holds a 30 -year Easement Maintenance: Town of Cary conducts monthly maintenance /inspections and submits an annual report to EEP Attachments: • Site Location Map • Watershed Map • Site Map • Design Calculations • As- Builts • Inspection Forms • MOA with Town of Cary r} ��ri'0 �eiemlt �111e K MAPS �N �9 2 NQ-7 S j CO 3 0 Figure 1. Site Location 9 0 cs J 2 O 5 ? - 5 70 c a� Durham h U �a ° Raleigh s`. h 1 inch = 1000 feet Cary c Site Z 4° d 5-64 o g 8 C ob a B �ep oo C.5 Q� z b O C w�HUT o� NC-2 0 N ?' 5�21 v N, 5 ti 1 inch = 10 miles ;9�4 lol\ 4A . Cm Figure 2. Watershed View � 0 N A 1 inch = 400 feet Figure 3. Site Layout Existinq Wet Pond 0 L: Sewer mate BMP Location L 1 1 inch = 100 feet DESIGN CALCULATIONS BARNES AND NOBLE EXTENDED DETENTION STORMWATER WETLAND WATERSHED AND BMP DATA d ,- • y A" ieape A .y r WATERSHED CHARACTERISTICS WATERSHED AREA - 46.3 ACRES SOIL HYDROLOGIC GROUP - B COMPOSITE CURVE NUMBER - 90 RUNOFF VOLUMES RUNOFF FROM 1" RAIN - 53826 CF ACTUAL WETLAND STORAGE VOLUME - 31590 CF WETLAND STORAGE CAPACITY COMPARED TO DESIGN VALUE- 60% MAX STORM DEPTH CAPTURED BY BMP- 0.8 IN it NUTRIENT REMOVAL PERFORMANCE TN LOADING - 12.9 LB /AC/YR TN REMOVAL FROM FULL -SIZED WETLAND - 40% *TN REMOVAL FROM UNDER -SIZED WETLAND - 40% X 0.9 = 36% TN EXPORT - 8.3 LB /AC/YR TN REMOVAL - 4.6 LB /AC/YR TP LOADING - 1.2 LB /AC/YR TP REMOVAL FROM FULL -SIZED WETLAND - 35% *TP REMOVAL FROM UNDER -SIZED WETLAND - 35% X 0.9 = 32% TP EXPORT - 0.8 LB /AC/YR TP REMOVAL - 0.4 LB /AC/YR * THE WETLAND WILL CAPTURE ALL RUNOFF FROM STORMS 0.8 INCHES AND SMALLER. THE ASSUMPTION IS MADE THAT 90% OF THE NUMBER OF STORMS WILL BE CAPTURED BY THE WETLAND COMPARED TO IF THE WETLAND WAS SIZED FOR THE 1 -INCH RAIN EVENT. NORTH CAROLINA STATE UNIVERSITY DEPARTMENT OF BIOLOGICAL AND AGRICULTURAL ENGINEERING r.: d ,- • y A" ieape A .y r WATERSHED CHARACTERISTICS WATERSHED AREA - 46.3 ACRES SOIL HYDROLOGIC GROUP - B COMPOSITE CURVE NUMBER - 90 RUNOFF VOLUMES RUNOFF FROM 1" RAIN - 53826 CF ACTUAL WETLAND STORAGE VOLUME - 31590 CF WETLAND STORAGE CAPACITY COMPARED TO DESIGN VALUE- 60% MAX STORM DEPTH CAPTURED BY BMP- 0.8 IN it NUTRIENT REMOVAL PERFORMANCE TN LOADING - 12.9 LB /AC/YR TN REMOVAL FROM FULL -SIZED WETLAND - 40% *TN REMOVAL FROM UNDER -SIZED WETLAND - 40% X 0.9 = 36% TN EXPORT - 8.3 LB /AC/YR TN REMOVAL - 4.6 LB /AC/YR TP LOADING - 1.2 LB /AC/YR TP REMOVAL FROM FULL -SIZED WETLAND - 35% *TP REMOVAL FROM UNDER -SIZED WETLAND - 35% X 0.9 = 32% TP EXPORT - 0.8 LB /AC/YR TP REMOVAL - 0.4 LB /AC/YR * THE WETLAND WILL CAPTURE ALL RUNOFF FROM STORMS 0.8 INCHES AND SMALLER. THE ASSUMPTION IS MADE THAT 90% OF THE NUMBER OF STORMS WILL BE CAPTURED BY THE WETLAND COMPARED TO IF THE WETLAND WAS SIZED FOR THE 1 -INCH RAIN EVENT. NORTH CAROLINA STATE UNIVERSITY DEPARTMENT OF BIOLOGICAL AND AGRICULTURAL ENGINEERING Tar - Pamlico Stormwater Rule 15A NCAC 2B .0258 Piedmont of the Tar - Pamlico River Basin: Includes Oxford, Henderson, Rocky Mount and Tarboro as well as Franklin, Nash and Edgecome Counties Last Modified 5/23/03 BMP Removal Calculation Worksheet (Automated) Project Name: BARNESAND NOBLE EXTENDED DETENTIONSTORMWATER WETLAND Date: 101712008 By: RYANSMITH Checked By: Directions: > It may be advantageous to split the development into separate catchments to be handled by separate BMPs. The tables below allow the development to be split into as many as three catchments, and can be copied for greater than three. NOTE: Unless runoff flowing onto the development from offsite is routed separately around or through the site, the offsite catchment area draining in must be included in the acreage values of the appropriate land use(s) and treated. > Above each table: Enter the catchment acreage in the top green blank. Based on a comparison of the post - development TN and TP export coefficients you calculated above to the rule requirements of 4.0 lb /ac /yr TN and 0.4 lb /ac /yr TP, select BMP(s) from the list for treating the catchment runoff. Enter the chosen BMP(s) nutrient removal rates in the green blanks. If more than one BMP is to be use in series, the combined removal rates will be calculated automatically in the blue blanks. > Catchment Tables: Enter the acres of each type of land cover in the green boxes. The spreadsheet will calculate all of the light blue boxes. NOTE: Compare the Total Catchment Acreage for the Development (final table) to the value you established in the pre -BMP worksheet tables, and also to the site plans, for consistency. All of these values need to be the same TN TP Design Standard BMP Wet Detention Pond 25 40 NC BMP Manual Nutrient Stormwater Wetland 40 35 NC BMP Manual Removal Sand Filter 35 45 NC BMP Manual Rates Bioretention 35 45 NC BMP Manual Grass Swale 20 20 NC BMP Manual Vegetated Filter Strip w/ 20 35 Level Spreader NC BMP Manual Dry Detention 10 10 NC BMP Manual Catchment 1: Total acreage of catchment 1 = ac First BMP's TN removal rate = 36 % First BMP's TP removal rate = % Second BMP's TN removal rate = % Second BMP's TP removal rate = % Third BMP's TN removal rate = % Third BMP's TP removal rate = % TOTAL TN REMOVAL RATE = 36 % TOTAL TP REMOVAL RATE = 32 % (1) (2) (3) (4) (5) (6) ( ) Type of Land Cover Catchment S.M. Formula Average EMC of Column Average EMC of Column Acrea e 0.46 +8.3I TN (mg/L 2 3 *'' 4 TP m L 2 *' 3 6 Transportation impervious 25.36 6.08 2.60 401.10 0.19 29.31 Roof impervious 5.97 6.08 1.95 70.82 0.11 3.99 Managed pervious 11.53 6.08 1.42 99.60 0.28 19.64 Wooded pervious 2.62 6.08 0.94 14.98 0.14 2.23 Area taken up by BMP 0.82 6.08 1.95 9.73 0.11 0.55 Fraction Impervious m - 0.68 Pre-BMP TN 596.22 Pre -BMP TP 55.72 Load (lb /yr) = Load (lb /yr) Total Area of Development - 46.30 Pre BMP TN '. ',. 12. 88 Pre BMP TP 1.20 Export (Ib /ac /yr) Export (Ib /acyr) = Post BMP TN Post BMP TP 381.58 37.89 Load (lb /yr) -, Load (lb/yr) - Past BMP TN 8.24 Post BMP TP 0.82 Export (Ib /ac /yr) Export (lb /ac/yr) AS- BUILTS Proposed Contours: N North Carolina State University Biological and Agricultural Engineering NCSU Box 7625 I Raleigh, N.C. 27695 Drawn By: RJW Reviewed By: WFH RA5 z SITE 0 0 GNUT c� VICINITY MAP (N.T.S) 35 °46'9" N 78 °45'38" W 35.7692° N 78.7606° W 24 RCP INV - 448.9' TOP - 459.0' 0 RCP INV - 448.5' � SGT F� D � As -Bu I It Contours As -Built Sheet Date: August 17, 201 1 Scale: I" =40 ft m , TOP - 457 PROPERTY BOUNDARY. J _D� -ate 40 d- d- O I OUTLET STRUCT BCW I NV-4 '7. 0' SECONDARY WEIR INV- 444.0' \ 48" RCP INV - 441.7' \ 48" RCP r. IN\i INS �i W1111mm 439.9' NV - 40.0' RP -0.1% 8" Cf '18' S T 7.6' W T .I S . NV.IP NV OU 4 LF 8" @ 3.70% d I TOP - 445.8' INV.IN- 437.4' %y BOUNDARY S FORCE MAIN (APPROXIMATE LOCATION) LF 8" PVC -LINED VCS@ 2.34% TOP - 455.6' INV.IN- 448.9' INV.OUT- 447.4' Barnes and Noble Extended Detention Stormwater Wetland 1208 Walnut Street Cary, NC 275 1 1 5CO No. 09 -08224-0 I A and EEP No. 667 PROPERTY BOUNDARY. Page Number of 2 As - Built: 450.6 450. N 450. 1 1 •1 RI PRAP POOL Ov 450.7 450.7 450. 0 7I] North Carolina State University Biological and Agricultural Engineering NCSU Box 7625 Raleigh, N.C. 27695 lo I� �Y 450.6 450.8 450.6 RIPRAP CHANNEL gs� As -15U11t with RIPRAP po FrO 5(5Ci Contours —450.5 5 —450.8 447.,r 447.0' 442. TOP OF DAM -Db and ate D eta I s : CONCRETE PIPE Scale: Not to scale CRADLES Drawn By: RJW Reviewed By: WFH RA-9 A5-bUllt5heet 2 Date: August 17, 201 1 �1 1 1 •1 Scale: III =30 ft L V- r/ i �V �\W) \! 491 I \ 440 1 4439 �� �I � 1 I cn Cf) 1� / �4 �/ � 4 ' ........ V 439 bc 0 01O ; fF. gg f' / Legend: - Proposed Contour — As -Built Mayor Contour (5 ft) As -Built Minor Contour (I ft) Scale: Not to scale l Barnes and Noble Extended Detention Stormwater Wetland 1 208 Walnut Street Cary, NC 2751 I SCO No. 09- 08224 -0 I A and EEP No. 667 Outlet Structure Details: N VALVE TAINLESS STEEL WEIR PLATE, DRMAL POOL F1 w = AAT EL. 442.07' CONCRETE F.. —, Page Number 2of2 PE INSPECTION FORMS iii( �S 's(a ti EEP Storinwater B P Inspection and I2eftortin I+'orni I S F ro "t ID #x667 Location:° Coi�li17o�1� (Barnes and l�oble), Cary Date: 2/24/2012 Time: 2:00 pm Recent Weather: 0.4" rain yesterday Inspector: Ryan A. Smith, PE Type of BMP® Stormwater Wetland Date of Construction. July 2011 To answer these questions completely and thoroughly, visually inspect the entire BMP as closely as possible Take notes and photographs Depth of water in forebayt 4 feet - -- -- - -- Is erosion present? N° -If yes, where: include photos) Is the outlet (orifice) obstructed, or can water flow freely out? The outlet is unobstructed Are plants alive and thriving? The shallow water plants needs to be replanted this May 1nClllde llOtOs Are non - native plants present? No (include photos) Is mowing occurring inside the boundaries of the BMP? No include pAotos Are beavers and /or muskrats present? No include liotos Is floating trash /debris present? Minimal Stormwater B P Maintenance Task Completed? Notes Clear outlet/orifice so water can exit Or N Y freely Remove non- - native plants Only Y or N Y Remove beaver darns Y Or N Y Remove floating trash /debris Y or N Y Remove accumulated sediment from Y Or N Y forebay Lam. � 0 tl Cary Commons Stormwater Wetland Photos — 2/24/2012 Figure 1. Northern half of the wetland Figure 2. Southern half of the wetland Figure 3. Walnut Street inlets Figure 4. Cary Commons inlet Figure 5. Primary outlet structure and trash rack Figure 6. Emergency spillway Figure 7. Primary wetland outlet pipe MEMORANDUM of AGREEMENT Memorandum of Agreement NC Ecosystem Enhancement Program and Town of Cary A. Introduction P ©c I ace The mission of the NCDENR Ecosystem Enhancement Program (EEP) is to restore, enhance, and preserve wetlands, streams, and riparian buffer areas, and to reduce the discharge of nutrients into surface waters throughout North Carolina's 17 major river basins with the overall goals of improving water quality, in- stream and riparian habitat. EEP is interested in restoring and protecting the watershed functions of the Neuse River Drainage area, which includes the Town of Cary (TOC). The construction of stormwater treatment systems, commonly referred to as Stormwater Best Management Practices ( Stormwater BMPs) is an accepted method of improving water quality by reducing nutrient discharges into surface waters of the State. This Memorandum of Agreement (MOA) between EEP and TOC for a Stormwater BMP to be located on two parcels to be purchased by TOC. B. Background The purpose of this MOA is to define and set forth the responsibilities of TOC and EEP for the property acquisition, design, construction and maintenance of a Stormwater BMP. The entire costs associated with the design and construction of the Stormwater BMP will be funded by EEP through other contracts. The TOC will fund acquisition of the land for a 30 -year conservation easement. Maintenance of the Stormwater BMP to ensure proper function will be the responsibility of TOC and no monies will be paid to TOC. The Stormwater BMP will be constructed on two parcels of land located near the intersection of Walnut Road and Maynard Road in Cary, Wake County, North Carolina. The project site is identified as PIN # 077313047725 (currently owned by CK Cary Commons LLC) and PIN # 077313049865 (currently owned by Ruth H. Lewis) in the Wake County Register of Deeds. The Project is intended to enhance water quality within the Neuse River Drainage Area (Cataloging Unit # 03020201, Hydrologic Unit 03020201110010) through the reduction of nitrogen and phosphorous discharges into surface waters within the watershed. This reduction is to be accomplished through the use of a Stormwater Wetland BMP as outlined in the BARNES AND NOBLE PROJECT STATEMENT, a copy of which is attached hereto as ATTACHMENT 1. It is anticipated that the Stormwater Wet Pond BMP will reduce Total Nitrogen discharges from the 31 acre sub - watershed by approximately 25 %, or 282 pounds per year, and Total Phosphorous discharges by approximately 40 %, or 22 pounds per year. Page 1 of 6 C. Scope of Work Tasks and Responsibilities for TOWN OF CARY The Project is currently located entirely on two private parcels owned by CK Cary Commons LLC (PIN # 077313047725) and Ruth H. Lewis (PIN # 077313049865). The TOC shall acquire the conservation easement of 30 years by July 15, 2006. , The primary responsibilities of TOC during and after construction of the Project will be: 1. To provide a designated contact person from TOC to coordinate and review all aspects of the Project with EEP and its contractors or consultants. TOC will respond in writing to any Project approval request within thirty (30) days from the date of request. If TOC fails to respond within thirty (30) days of the request, the request will be deemed approved by the TOC. 2. Both entities also agree to work cooperatively to develop a remedial action plan (RAP) that is agreeable to both entities in the event that post - construction remedial activities are necessary. Details related to the implementation of the RAP will be jointly discussed by both entities as necessary. 3. To provide and ensure that EEP, its contractors and its consultants will be allowed reasonable access to the Stormwater BMP Project work site during normal working hours. 4. To provide for public safety and work place security by keeping work areas closed to the public as necessary throughout the constructions phases of the Project. Contractors will follow standard OSHA guidelines and will post the construction site. 5. TOC will designate a contact person and/or Public Information Officer that will notify or consult with EEP prior to issuing news releases relating to the Project. 6. To meet with EEP and/or its contractors and consultants at least every two months to review and assess the Project's plans and progress. 7. TOC will submit a Stormwater BMP maintenance and inspection report to EEP every one (1) year for a period of thirty (3 0) years at no cost to EEP. 8. TOC will maintain the Stormwater BMP to ensure functionality for a period of 30- years at no cost to EEP. Page 2 of 6 Tasks and Responsibilities for Ecosystem Enhancement Program The primary responsibilities of EEP during and after this project will be: 1. To design and construct the stormwater BMP at no cost to TOC. 2. Both entities also agree to work cooperatively to develop a remedial action plan (RAP) that is agreeable to both entities in the event that post - construction remedial activities are necessary. Details related to the implementation of the RAP will be jointly discussed by both entities as necessary. 3. To consult with TOC's designated contact person and/or Public Information Officer and staff prior to issuing news releases relating to the Project. 4. To meet with TOC staff to review and assess the project's progress, as specified in Section 3, item No. 5 of this MOA. A minimum of four (4) meetings will be held with TOC to discuss the Project and receive input. These meetings will be held after preparation of the Draft Design Plan (30% complete design), after preparation of the Final Design Plan, prior to the Pre - Construction Meeting and prior to the Post - Construction Meeting. 5. To obtain any state, federal or local permits necessary for construction of the Project. D. Timeline and Duration of this Agreement The Project shall commence on the date a Memorandum of Agreement (MOA) is signed by all parties. The site maintenance phase of the Project will commence upon completion of the Stormwater BMP construction. TOC agrees to maintain the constructed Stormwater BMP site for a 30 -year period and submit site maintenance and inspection reports to EEP every one (1) year for a period of thirty (30) years following completion of the construction phase of the project. E. Limitations 1. This MOA will not transfer the ownership of the land or the management and maintenance responsibilities for the Project from TOC to EEP. All provisions of this MOA will be consistent with such understanding. 2. If either party fails to perform or comply with any condition of this MOA, and should such failure continue more than 30 -days after written notice from the other party, and if the non - compliant party should not within 30 -days commence to cure the failure with due diligence, the aggrieved party may terminate this MOA on written notice to the non- compliant party, termination to be effective not less than 15 days from the date of the written termination notice. Page 3 of 6 I The failure of either party to insist on strict performance of any condition of this MOA shall not be construed as a waiver of the right to insist on the performance of that condition in any other instance. 4. This MOA may be modified or terminated by mutual agreement of the parties as long as such modification or termination is made in writing and signed by authorized officers or agents for each of the parties. Page 4 of 6 IN TESTIIMONY WHEREOF, the Town has caused this instrument to be executed in its name by its Manager and attested by its Clerk, and its Seal affixed thereto by authority duly given. (SEAL) STATE C TOWN C William B. Coleman, Jr. l� Qa.,4ekj&W=@j-t}re Town Manager Notary Publ' in and for the County and State aforesaid, do hereby certify that ���, e personally came before me this day and acknowledged that she is ( nd that by authority duly given and as an act of y�,�, o F 0tir _, the foregoing instrument was signed by ( Ili I I i awr, 6, a4e ,mar, its Towo a L '�.. as by.hi� as 1 6"� i� c� and sealed with the common seal of said C' unty. h� J IN WITHNESS WHEREOF, I have hereunto set my hand and Notarial Seal this the _1c day of , 20�. Dom- Notary Public My commission expires: G/1 G /,20io DONNA CARPENELLI TORRISI Notary Public, North Carolina Wake County My Coln�l sslo �E PPS !CERTIFICATE OF TOi6 N (3F CA ti' Ft ,ttiCE f�FFJ�_ii Provision for the payment of the monies to fall due under this agreement has been made by appropriation duly made or by bonds or notes duly authorized, as required by the "Municipal Fiscal Control Act." sl I;k 1 aob Chgn rat � Date 1)erittS inance Officer .J Page 5 of 6 IN TESTIMONY WHEREOF, the State has caused this instrument to be executed in its name by its �-o�,c e- �,,.a„d attested by its ; �c { o-� , and its Seal affixed thereto by authority duly given. O�erA�. ahS Print Name & Title: North Carolina Department of Environment and Natural Resources Jj P STATE OF NORTH CAROLINA -\MA_ COUNTY I, �� �'� �eby AN �Khaqtt �, a Notary Public in and for the County and State aforesaid, do certify ��2 g�,� k ; personally came before me this day and acknowledged thatshe is l '%% f—C nt po Ccc},pnG , and that by authority duly given and as an act of lycpthe foregoing instrument was signed by $y ZA &t IN AITHNESS WHEREOF, I have hereunto set my hand and Notarial Seal this the day of a 20p_( No bji!e My commission expires: Hy, ,�...M. H0R =f TL <Z o of A R Y °y'•z W= tj Page 6 of 6