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HomeMy WebLinkAbout20081213 Ver 2_More Info Received_20081118o$ -12-13 LJ Z ? M ? Kimley-Horn and Associates, Inc. Transmittal Suite 300 4651 Charlotte Park Drive Charlotte, North Carolina 28217 TEL 704 333 5131 FAX 704 333 0845 Date: November 17, 2008 Job Number: 018256026 Project Name: South Tract City Blvd Development Stormwater Management Plans To: Joseph Gvamfi Division of Water Quality 2321 Crabtree Blvd, Suite 250 Raleigh, NC 27604 919-715-3473 We are sending these by E] U.S. Mail Other: NOV 1 8 2008 DENK - VVAf EK ()UAL17YY WETLANDS AND STORMWATER BRANCH M FedEx n Hand Deliver We are sending you MAttached Shop Drawings Other: Under separate cover via M Prints/Plans Fj Samples the following items: ? Specifications ? Change Orders Copies Date No. Description 2 11/17/08 1 Revised South Tract City Blvd Stormwater Management Plans 2 11/17/08 2 Revised South Tract City Blvd Stormwater Management Calculations 3 11/17/08 3 Signed Stormwater Management Application 3 11/17/08 4 Signed Operation and Maintenance Agreements These are transmitted as checked below: M For your use Approved as submitted Resubmit Copies for approval ? As requested Approved as noted E] Submit Copies for distribution M For review and comment Returned for corrections ? Return ? Corrected prints Copy to: Signed Beverly Rosenbloom, E.I. Page 1 OFFICE USE ONLY Date Received Fee Paid Permit Number(s) State of North Carolina Department of Environment and Natural Resources Division of Water Quality 401/Wetlands Unit EXPRESS REVIEW PROGRAM STORMWATER MANAGEMENT APPLICATION FORM This form may be photocopied for use as an original 1. GENERAL INFORMATION 1. Applicant's name (specify the name of the corporation, individual, etc. who owns the project): Crescent Resources LLC 2. Owner/Signing Official's name and title (person legally responsible for facility and compliance): David Niekamp- Director of Retail Development 3. Owner Mailing Address for person listed in item 2 above: 400 S. Tryon Street, Suite 1300 City: Charlotte State: NC Longitude: 80.7639 W Zip: 28285 Phone Number: (980 321-6181 Fax Number: (980 321-6170 Email Address: DJNiekamp@crescent- resources.com 4. Project Name (subdivision, facility, or establishment name - should be consistent with project name on plans, specifications, letters, inspection and maintenance agreements, etc.): South Tract City Boulevard Development 5. Location of project (Street Address): Immediately South of City Blvd. City: Charlotte County: Mecklenburg 6. Directions to project site (from nearest major intersection): Immediately off of Exit 43 on Interstate 85 then south on City Boulevard 7. Latitude: 35.2931 N 8. Contact person who can answer questions about the project: Name: Matthew A. Edwards Fax Number: (704 333-0845 of project Telephone Number: (7"4 954-7493 Email Address: matt. Edwards@Kimley-horn. com 1/2008 Version 1.0 Page 1 of 5 R u:i L 01- WIN WE' LANDS AND STORWA/Afci< t,tt;?NGr; II. PERMIT INFORMATION 1. Specify whether project is (check one): ?= New Renewal Modification 2. If this is a new project, under which local government's jurisdiction does the project fall (e.g. Town of Cary, City of Raleigh, or Wake County)? City of Charlotte 3. Is there a state-approved stormwater management program implemented by the local government or state under any of the following programs (Check all that apply)? Phase II Post Construction Water Supply Watershed Neuse or Tar Pamlico NSW Randleman WSWS USMP Coastal Counties HQW ORW 4. If this application is being submitted for a renewal or modification to an existing permit, list the existing permit number and its issue date (if known) 5. Specify the type of project (check one): Low Density =High Density Redevelopment General Permit Other 6. Additional Project Requirements (check the ones applicable): CAMA Major OSedimentation/Erosion Control=404/401 Permit NPDES Stormwater -Other Already obtained Already obtained Information on required state permits can be obtained by contacting the Customer Service Center at 1-877-623-6748 III. PROJECT INFORMATION 1. In the space provided below, summarize how stormwater will be treated. Also attach a detailed narrative (one to two pages) describing stormwater management for the project. The development will be treated by two wet detention ponds. Storm-water will be collected by a storm sewer system and directed to the ponds. 2. Stormwater runoff from this project drains to the 3. Total Project Area: 40.8 acres Yadkin River basin. 4. Project Built Upon Area: 58.3 % 23.77 acres 5. How many drainage areas does the project have? 2 6. Complete the following information for each drainage area. If there are more than two drainage areas in the project, attach an additional sheet with the information for each area provided in the same format as below. Basin Information Receiving Stream Name Drainage Area I UT to Doby Creek Drainage Area 2 UT to Doby Creek Receiving Stream Class Drainage Area 7.20 acres 23.91 acres Existing Impervious* Area 0 0 Proposed Impervious*Area 6.48 acres 17.29 acres % Impervious* Area (total) 90$ 7596 1/2008 Version 1.0 Page 2 of 5 Impervious* Surface Area On-site Buildings Drainage Area 1 Drainage Area 2 On-site Streets On-site Parking On-site Sidewalks Other on-site Off-site 0 0 Total: 6.48 acres Total: 17.29 acres * Impervious area is defined as the built upon area including, but not limited to, buildings, roads, parking areas, sidewalks, gravel areas, etc. 7. How was the off-site impervious area listed above derived? N/A IV. DEED RESTRICTIONS AND PROTECTIVE COVENANTS The following italicized deed restrictions and protective covenants are required to be recorded for all subdivisions, outparcels and future development prior to the sale of any lot. If lot sizes vary significantly, a table listing each lot number, size and the allowable built-upon area for each lot must be provided as an attachment. 1. The following covenants are intended to ensure ongoing compliance with state riparian buffer authorization or General Certification numbers as issued by the Division of Water Quality. These covenants may not be changed or deleted without the consent of the State. For drainage area one (1), no more than 90% of any single lot 2. shall be covered by structures or impervious materials. Impervious materials include asphalt, gravel, concrete, brick, stone, slate or similar material but do not include wood decking or the water surface of swimming pools. For drainage area two (2) , no more than 75% of any single lot shall be covered by structures or impervious materials. 3. Swales shall not be filled in, piped, or altered except as necessary to provide driveway crossing. 4. Built-upon area in excess of the permitted amount requires a modified water quality certification prior to construction. 5. All permitted runofffrom outparcels or future development shall be directed into the permitted stormwater control system. These connections to the stormwater control system shall be performed in a manner that maintains the integrity and performance of the system as permitted. By your signature below, you certify that the recorded deed restrictions and protective covenants for this project shall include all the applicable items required above, that the covenants will be binding on all parties and persons claiming under them, that they will run with the land, that the required covenants cannot be changed or deleted without concurrence from the State, and that they will be recorded prior to the sale of any lot. 1/2008 Version 1.0 Page 3 of 5 V. SUPPLEMENT FORMS The applicable stormwater management supplement form(s) listed below must be submitted for each BMP specified for this project. The most current form(s) located on the 401/wetlands unit website at ht!p:Hh2o.enr.state.nc.us/su/bmi) forms.htm must be used. Please include both the Design Summary and the Required Items Checklist along with all required items and supporting design calculations. Bioretention Supplement Wet Detention Supplement Dry Detention Supplement Level Spreader/Filter Strip/Restored Buffer Supplement Stormwater Wetland Supplement Grassed Swale Supplement Sand Filter Supplement Infiltration Trench Supplement Infiltration Basin Supplement VI. SUBMITTAL REQUIREMENTS Only complete application packages will be accepted and reviewed by the Division of Water Quality (DWQ). A complete package includes all of the items listed below. The complete application package should be submitted to the DWQ Central Office. Please indicate that you have provided the following required information by initialing in the space provided next to each item. Initials • Original and two copies of the Express Review Stormwater Management Application • Signed and Notarized Inspection and Maintenance Agreement • Three copies of the applicable Supplement Form(s) for each BMP • Application processing fee (payable to DWQ) • Detailed narrative description of stormwater treatment/management • Three copies of plans and specifications, including: - Development/Project name - Engineer and firm - Legend - North arrow - Scale - Revision number & date - Mean high water line - Dimensioned property/project boundary - Location map with named streets or NCSR numbers - Original contours, proposed contours, spot elevations, finished floor elevations - Details of roads, drainage features, collection systems, and stormwater control measures - Wetlands and streams delineated, or a note on plans that none exist - Existing drainage (including off-site), drainage easements, pipe sizes, runoff calculations - Drainage areas delineated - Vegetated buffers (where required) 1/2008 Version 1.0 Page 4 of 5 VII. AGENT AUTHORIZATION If you wish to designate authority to another individual or firm so that they may provide information on your behalf, please complete this section. Designated agent (individual or firm): Kimley-Horn and Associates, Inc. Contact: Matthew A. Edwards, PE Mailing Address: 4651 Charlotte Park Drive, Suite 300 City: Charlotte State: North Carolina Zip: 28217 Phone: (704 954-7493 Fax: (704 333-0845 VIII. APPLICANT'S CERTIFICATION I, (print or type name of person listed in General Information, item 2) David Niekamp certify that the information included on this application form is, to the best of my knowledge, correct and that the project will be constructed in conformance with the approved plans, that the required deed restrictions and protective covenants will be recorded, and that the proposed project complies with the requirements of 15A NCAC 21-1.1000. Signatur : Date: & ?!?? 1/2008 Version 1.0 Page 5 of 5 f?l Cf?"'?I=?a t( 1 1L y EpE,R . ran i i.F uu, ,L 1'(Y Permit Number: 1VF LAN )5 AND STORM' A'HrFh; t3tUV?CN (to be provided by DWQ) Drainage Area Number: Wet Detention Basin 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. The wet detention basin system is defined as the wet detention basin, pretreatment including forebays and the vegetated filter if one is provided. This system (check one): ? does ® does not incorporate a vegetated filter at the outlet. This system (check one): ? does ® does not incorporate pretreatment other than a forebay. Important maintenance procedures: - Immediately after the wet detention basin is established, the plants on the vegetated shelf and perimeter of the basin should be watered twice weekly if needed, until the plants become established (commonly six weeks). - No portion of the wet detention pond should be fertilized after the first initial fertilization that is required to establish the plants on the vegetated shelf. - Stable groundcover should be maintained in the drainage area to reduce the sediment load to the wet detention basin. - If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment through the emergency drain should be minimized to the maximum extent practical. - Once a year, a dam safety expert should inspect the embankment. After the wet detention pond is established, it should be inspected 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 should be kept in a known set location and must be available upon request. Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately. BMP element: Potential problem: How I will remediate the problem: The entire BMP Trash/debris is resent. Remove the trash debris. The perimeter of the wet Areas of bare soil and/or Regrade the soil if necessary to detention basin 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. Vegetation is too short or too Maintain vegetation at a height of long. approximately six inches. Form SW401-Wet Detention Basin O&M-Rev.3 Page 1 of 4 Permit Number: (to be provided by DWQ) Drainage Area Number: BMP element: Potential problem: How I will remediate the problem: The inlet device: pipe or The pipe is clogged. Unclog the pipe. Dispose of the swale sediment off-site. The pipe is cracked or Replace the pipe. otherwise damaged. Erosion is occurring in the Regrade the Swale if necessary to swale. smooth it over and provide erosion control devices such as reinforced turf matting or riprap to avoid future problems with erosion. The forebay Sediment has accumulated to Search for the source of the a depth greater than the sediment and remedy the problem if original design depth for possible. Remove the sediment and sediment storage. dispose of it in a location where it will not cause impacts to streams or the BMP. 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. If pesticide is used, wipe it on the plants rather than spraying. The vegetated shelf Best professional practices Prune according to best professional 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. Weeds are present. Remove the weeds, preferably by hand. If pesticide is used, wipe it on the plants rather than spraying. The main treatment area Sediment has accumulated to Search for the source of the a depth greater than the sediment and remedy the problem if original design sediment possible. Remove the sediment and storage depth. dispose of it in a location where it will not cause impacts to streams or the BMP. Algal growth covers over Consult a professional to remove 50% of the area. and control the algal growth. Cattails, phragmites or other Remove the plants by wiping them invasive plants cover 50% of with pesticide (do not spray). the basin surface. Form SW401-Wet Detention Basin O&M-Rev.3 Page 2 of 4 Permit Number: (to be provided by DWQ) Drainage Area Number: BMP element: Potential roblem: How I will remediate the problem: The embankment Shrubs have started to grow Remove shrubs immediately. on the embankment. Evidence of muskrat or Use traps to remove muskrats and beaver activity is present. consult a professional to remove beavers. A tree has started to grow on Consult a dam safety specialist to the embankment. remove the tree. An annual inspection by an Make all needed repairs. appropriate professional shows that the embankment needs repair. The outlet device Clogging has occurred. Clean out the outlet device. Dispose of the sediment off-site. The outlet device is damaged Repair or replace the outlet device. The receiving water Erosion or other signs of Contact the local NC Division of damage have occurred at the Water Quality Regional Office, or outlet. the 401 Oversight Unit at 919-733- 1786. The measuring device used to determine the sediment elevation shall be such that it will give an accurate depth reading and not readily penetrate into accumulated sediments. When the permanent pool depth reads 8 feet in the main pond, the sediment shall be removed. When the permanent pool depth reads 8 feet in the forebay, the sediment shall be removed. BASIN DIAGRAM (fill in the blanks) Permanent Pool Elevation 726 Sediment Removal .718 1 Pe anen Pool ---_------__- -- Volume Sediment Removal Elevation 718 Volume Bottom Elevati 717 ft Min. '"""-------"'"'--""-''--""'"""' Sediment Bottom Elevation 717 1-ft n Storage imer Storage FOREBAV MAIN POND Form SW401-Wet Detention Basin 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: South Tract City Boulevard Development BMP drainage area number: I Print name:Crescent Resources. LLC - David Niekamp Title:Director of Retail Development Address:400 South Tryon Street. Suite 1300. Charlotte. NC 28285 Phone: 980-321-6181 .0 4 Signature: Date: 01IF„i'tdb11 _ l Z ZOg(b 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. a Notary Public for the State of Count of do hereby certify that ' j? V lb personally appeared before me this./ day of AloV,4,M?'--' 40 F , and acknowledge the due execution of the forgoing wet detention basin maintenance requirements. Witness my hand and official seal, SEAL My commission expires Con AUgusi 17, 2013 Form SW401-Wet Detention Basin O&M-Rev.3 Page 4 of 4 ??ov ? ? ?t108 Permit Number: p?N? , aehltr ???L'a??R,NpN (to be provided by DWQ) w?Ttp?kps AND STQRMWACER ` Drainage Area Number: Wet Detention Basin 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. The wet detention basin system is defined as the wet detention basin, pretreatment including forebays and the vegetated filter if one is provided. This system (check one): ? does ® does not incorporate a vegetated filter at the outlet. This system (check one): ? does ® does not incorporate pretreatment other than a forebay. Important maintenance procedures: - Immediately after the wet detention basin is established, the plants on the vegetated shelf and perimeter of the basin should be watered twice weekly if needed, until the plants become established (commonly six weeks). - No portion of the wet detention pond should be fertilized after the first initial fertilization that is required to establish the plants on the vegetated shelf. - Stable groundcover should be maintained in the drainage area to reduce the sediment load to the wet detention basin. - If the basin must be drained for an emergency or to perform maintenance, the flushing of sediment through the emergency drain should be minimized to the maximum extent practical. - Once a year, a dam safety expert should inspect the embankment. After the wet detention pond is established, it should be inspected 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 should be kept in a known set location and must be available upon request. Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately. BMP element: Potential problem: How I will remediate the problem: The entire BMP Trash debris is resent. Remove the trash debris. The perimeter of the wet Areas of bare soil and/or Regrade the soil if necessary to detention basin 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. [Vegetation is too short or too Maintain vegetation at a height of lon . a roximatel six inches. Form SW401-Wet Detention Basin O&M-Rev.3 Page 1 of 4 Permit Number: (to be provided by DWQ) Drainage Area Number: BMP element: Potential problem: How I will remediate the problem: The inlet device: pipe or The pipe is clogged. Unclog the pipe. Dispose of the swale sediment off-site. The pipe is cracked or Replace the pipe. otherwise damaged. Erosion is occurring in the Regrade the swale if necessary to swale. smooth it over and provide erosion control devices such as reinforced turf matting or riprap to avoid future problems with erosion. The forebay Sediment has accumulated to Search for the source of the a depth greater than the sediment and remedy the problem if original design depth for possible. Remove the sediment and sediment storage. dispose of it in a location where it will not cause impacts to streams or the BMP. 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. If pesticide is used, wipe it on the plants rather than spraying. The vegetated shelf Best professional practices Prune according to best professional 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. Weeds are present. Remove the weeds, preferably by hand. If pesticide is used, wipe it on the plants rather than spraying. The main treatment area Sediment has accumulated to Search for the source of the a depth greater than the sediment and remedy the problem if original design sediment possible. Remove the sediment and storage depth. dispose of it in a location where it will not cause impacts to streams or the BMP. Algal growth covers over Consult a professional to remove 50% of the area. and control the algal growth. Cattails, phragmites or other Remove the plants by wiping them invasive plants cover 50% of with pesticide (do not spray). the basin surface. Form SW401-Wet Detention Basin O&M-Rev.3 Page 2 of 4 Permit Number: (to be provided by DWQ) Drainage Area Number: BMP element: Potential problem: How I will remediate the problem: The embankment Shrubs have started to grow Remove shrubs immediately. on the embankment. Evidence of muskrat or Use traps to remove muskrats and beaver activity is present. consult a professional to remove beavers. A tree has started to grow on Consult a dam safety specialist to the embankment. remove the tree. An annual inspection by an Make all needed repairs. appropriate professional shows that the embankment needs repair. The outlet device Clogging has occurred. Clean out the outlet device. Dispose of the sediment off-site. The outlet device is damaged Repair or replace the outlet device. The receiving water Erosion or other signs of Contact the local NC Division of damage have occurred at the Water Quality Regional Office, or outlet. the 401 Oversight Unit at 919-733- 1786. The measuring device used to determine the sediment elevation shall be such that it will give an accurate depth reading and not readily penetrate into accumulated sediments. When the permanent pool depth reads 7 feet in the main pond, the sediment shall be removed. When the permanent pool depth reads 3 feet in the forebay, the sediment shall be removed. BASIN DIAGRAM Ti11 in the blanks) Permanent Pool Elevation 719 Sediment Removal E. 716 ---------- P an Pool -- Volume ---Sedi --ment-- Removal Elevation 211 Volume Bottom E evati 71 ft Min. -------------------- -Sediment--- Bottom-Elevation 711 n Storage FOREBAY MAIN POND Storage Form SW401-Wet Detention Basin 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:South Tract City Boulevard Development BMP drainage area number: Print name:Crescent Resources. LLC - David Niekagp Title:Director of Retail Development Address:400 South Tryon Street. Suite 1300. Charlotte. NC 28285 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. a Notary Public for the State of do hereby certify that appeared before me this and acknowledge the due execution of the forgoing wet detention basin maintenance requirements. Witness my hand and official seal, SEAL My Commission E)PIM August 17,2013 My commission expires Form SW401-Wet Detention Basin O&M-Rev.3 Page 4 of 4 Date: tV/)UC?J3(i4_ )$ O$ -[2-13 VZ I 1 Revised Stormwater Management Calculations 1 South Tract ? City Boulevard Development 11 F 1 Prepared for: 1 Crescent Resources, LLC 400 S. Tryon Street, Suite 1300 1 Charlotte, North Carolina 28202 © Kimley-Horn and Associates, Inc. 2008 1 Kimley-Horn ? 1 ? and Associates, Inc. #Z? 1 ' SOUTH TRACT CITY BOULEVARD DEVELOPMENT CHARLOTTE, NORTH CAROLINA REVISED STORMWATER MANAGEMENT CALCULATIONS ' Prepared for: ' Crescent Resources, LLC 400 S. Tryon Street, Suite 1300 Charlotte, North Carolina 28202 ' P d b repare y: Kimley-Horn and Associates, Inc. ' 4651 Charlotte Park Drive, Suite 300 Charlotte, North Carolina 28217 , SCAR®?i ?i 'FESSi E r' 40 %XX(? ' NOVEMBER 2008 KHA Ref: 018253026 1 1 1 1 1 1 i 1 TABLE OF CONTENTS OVERVIEW SITE MAPS SITE VICINITY MAP SCS SOIL SURVEY FEMA FIRM PANEL WATERSHED MAPS PRE-DEVELOPMENT WATERSHED MAP POST-DEVELOPMENT WATERSHED MAP WATER QUALITY WET POND CALCULATIONS ANTI-FLOTATION DEVICE CALCULATIONS VOLUME AND SURFACE AREA TABLES WET DETENTION BASIN SUPPLEMENT FORMS WATER QUANTITY CURVE NUMBER CALCULATIONS TIME OF CONCENTRATION CALCULATIONS HYDROCAD HYDROLOGY REPORT STORMWA TER MANAGEMENT CALCULATIONS South Tract City Boulevard Development, Charlotte, NC i Background OVERVIEW This report contains the approach and results of a stormwater analysis conducted for the South Tract City Boulevard Development. The 41-acre project site is located in the southeast quadrant of the interchange of Interstate 85 and City Boulevard in the City of Charlotte (see vicinity map). The site has been mass graded per City of Charlotte permit number GRS-2007223. Existing Conditions The existing on-site conditions (before mass grading) consisted of woods and meadow therefore this ground cover was used in the analysis. The site topography varies from elevation 770 ft to elevation 720 ft. Site runoff discharges into an existing stream in the middle portion of the site. This stream drains to a culvert under City Blvd. Floodplain/Floodway The proposed site does not lie within a 100-year floodway boundary as determined by FIRM Panel # 3717900070C. Water Quality Water quality treatment by means of permanent Best Management Practices (BMP's) will be provided using two wet ponds as treatment. The ponds are designed to treat the first inch of runoff per the Stormwater Model Ordinance for North Carolina and will draw down over a period of two to five days. Wet Detention Basin 1 and Wet Detention Basin 2 have been designed to provide a minimum 90% average annual removal of Total Suspended Solids (TSS). Water Quantity The proposed wet detention ponds have been designed to address the water quantity requirements to match pre- and post-development peak runoff rates for the 1-year, 24-hour storm events. (These ponds will also control the peak runoff rates for the 10- and 25-year, 6-hour storm events per the City of Charlotte rezoning notes on Petition 2006-155. However, these water quantity requirements will be reviewed by the City of Charlotte when the site develops.) The 100-year, 24-hour storm event was checked for 6" of freeboard at the top of bank. Results Pre-development 1-yr, 24-hr storm Post-development 1-yr, 24-hr storm DA-1 2.63 cfs 1.80 cfs DA-2 1.57 cfs 1.50 cfs STORMWA TER MANAGEMENT CALCULATIONS South Tract City Boulevard Development, Charlotte, NC 1 11 it 1 Conclusion The proposed wet detention basins were designed using methods prescribed by the aforementioned resources. HydroCAD software was utilized to evaluate the pre-development and post-development flow rates. HydroCAD utilizes TR-55 methods of calculating times of concentration (based on sheet, shallow concentrated, and channelized flows) and SCS curve number method of generating hydrographs (results are provided in Appendix C). Based on the analyses provided herein, the proposed system will be adequate to address the stormwater requirements of the North Carolina Department of Environment and Natural Resources, Division of Water Quality. ' STORMWA TER MANAGEMENT CALCULATIONS South Tract City Boulevard Development, Charlotte, NC 1 SITE MAPS STORMWA TER MANAGEMENT CALCULATIONS ' South Tract City Boulevard Development, Charlotte, North Carolina t,e;aL F m tit n? i), I II Y O t et A 4 ' i -lei a I PROJECT LOCATION' STr I% ??_? CIS Tarn Hun ELMO Rd:- 29' i j y A I 1 I BELGATE VICINITY MAP FIGURE Kimley-Horn and Associates, Inc. SOUTHERN TRACT NTS ' IM DOQII M 700CM KIM 7W OOROEP. 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R i a m m x O O N o m =a 3 m v _ ° m c m° < N ? 1 1 1 1 1 1 1 PRE-DEVELOPMENT WATERSHED MAP 31'URMWATER MANAGEMENT CALCULATIONS South Tract City Boulevard Development, Charlotte, North Carolina ? ggpg l y } g eraaeln3n e?d3wwoo ovo uyloy 161pi M3a sNasln3li ??'° iN[vli t 5SZBZ ON'31101LVHO OOfL'316 133d1S NOAkIl'S OOb 0ll'63ONIlOS3il1N30SRN0 ZSZSZ'VNnOLVO H1NON A1Nl1000lIf16N31N03W'311011lVH0 'Ml8A1100NV58-I a o t; "_ € P dvw V3ad 4 f d `?'-j`j 3E)HNIVHO1N3WdOl3A30-3t1d o ! ? ayy w SNV Id 1N3W30VINVW V31VMWVOLB m 4 X q M ip 11. a all" OG A113 IOVVI N1flOS e m 3b ax?ro a? 3uu pd S I ' ' I W t. ? -41 I I, r - ! , 0• e ? flul I I t (((?aaaJ]]] 9 U Y ? N U x ?$ a u 9 1 1 1 1 1 POST-DEVELOPMENT WATERSHED MAP STORMWA TER MANAGEMENT CALCULATIONS ' South Tract Ciry Boulevard Development, Charlotte, North Carolina ? c ?- 9N[)ISIA3U ava 'ON N N ON'3 S NOA I' ZSZBZ NI31A03 H121 o y?S ? ? ewawwoo anowroB iseiiaaa e4aslnau ewun[ [ 0061 ME 'ME '133i11S NOAiIlS B06 A1Nf100 OHf1GN3lN03W'3110 10121VH0 0II'S30tlf10S3H IN93SREIO 'OAIB A110 ONV 98-I dVW d3aV a a ° N BENNIVIdO1N3WdOl3A30-1SOd o u ¢¢ gk w 6 SNVId 1N3W30VNVW V31VMWHOIB m m '?` Ba o a av"31009 A11013VNl HIM s :1p31D :1J3rotld '311LL g o z w c? w w c? Q z Q 0 T / AI//A¦in y - I - L-- -- ----- i F ;IIL -------- `i J. I - - I i ='a - I i C I I W ?'? - 4 zQ Q U LO 0 r-, I _ ?? ? F - ?a Z I I 1 r r - 10- -I 04 ZN L -- N U II l-? • - 1 I ,I --- --------------- • I _i I • I I i:., I F • I I I I r ? I I I f I ;.. ?I I ? I I I I 1 77. I I I` won I, r?,-u,-?uu< uv p a\ n a?oa\?m I-uop ?,o?wnl5 4oBpg\alo[pe i[0\I'.. CS[B1o\A3u1-lq\?M WET POND CALCULATIONS STORMWA TER MANAGEMENT CALCULATIONS ' South Tract City Boulevard Development, Charlotte, North Carolina PIP-111111111111111111" Kimley-Horn ®® and Associates, Inc. ' WET DETENTION BASIN Project Information ' Project Name: Belgate - Southern Tract KHA Project #: 018253026 Designed by: BRR Date: 10/8/2008 ' Revised by: BRR Date: 10/27/2008 Revised by: BRR Date: 11/14/2008 Site Information Sub Area Location: Drainage Area 1 Drainage Area (DA) = 7.15 Acres Impervious Area (IA) = 6.43 Acres ' Percent Impervious (1) = 89.9 % Required Surface Area Permanent Pool Depth: 4 ft ' SA/DA = 4 (90% TSS Removal via Pond) Min Req'd Surface Area = 12458 sf (at Permanent Pool) Required Storage Volume: Design Storm = 1 inch (Project Does Not Drain to SA waters) Determine Rv Value = 0.05 + . 009 (1) = 0.86 in/in Storage Volume Required = 22305 cf (above Permanent Pool) ' Elevations Area (s.f.) Bank Elevation = 732.00 ft Top of Pond Elevation = 732.00 ft ' Temporary Pool Elevation = 727.70 ft 16,459 Permanent Pool Elevation = 726.00 ft 13,220 Shelf Beginning Elevation = 726.50 ft ' Forebay Weir = 728.00 ft Shelf Ending Elevation = 725.50 ft Sediment Cleanout Elevation = 718.00 ft ' Bottom Elevation = 717.00 ft Wet Basin Areas/Volumes (Elevation = 727.70) Area @ Top of Temporary Pool = 16459 sf (Elevation = 726.00) ' Area @ Top of Permanent Pool = 13220 sf Volume of Temporary Storage = 25227 cf Side Slopes of Pond = 3 :1 Side Slopes of Shelf = 1 0 :1 Side Slopes of Pond (below shelf) = 3 :1 Yes ( 13220 > 12458) sf ' Is Permanent Pool Surface Area Sufficient (yes/no)? Volume of Storage Provided 25227 cf ' Total Volume Sufficient (yes/no)? Yes Orifice Size = 2.30 inches 1 1 1 1 1 1 1 1 1 1 WET DETENTION BASIN Project Information Project Name: Belgate - Southern Tract KHA Project #: 018253026 Designed by: BRR Date: Revised by: Date: Revised by: BRR Date: Site Information 4/1/2008 11114/2008 Sub Area Location: Drainage Area 1 Drainage Area (DA) = 7.15 Acres Impervious Area (IA) = 6.48 Acres Percent Impervious (1) = 90.6 % (Drainage Area) Orifice Sizing Q2 Days = 0.1460 cfs Qs Days = 0.0584 cfs Orifice Size = 2.30 in Q or?ce = 0.102 cfs Drawdown Time = 2.9 days less than 5 days (yes/no) ? yes greater than 2 days (yes/no) ? yes (Flowrate required for a 2 day drawdown) (Flowrate required for a 5 day drawdown) (Diameter) Orifice Equation: Q=cAgV(2gh) Q2 < Q < Qs c = 0.6 A9= Area of Pipe = Tr/4D2 g = gravity = 32.2 ft/s2 h = orifice head = 1/3 (TPE-PPE-1/2D) TPE = Temporary Pool Elevation PPE = Permanent Pool Elevation D = Diameter ® Kimley-Horn and Associates, Inc. WET DETENTION BASIN Project Information ' Project Name: Belgate - Southern Tract KHA Project #: 018253026 Designed by: BRR Date: 10/8/2008 ' Revised by: BRR Date: 10/19/2008 Revised by: BRR Date: 11/14/2008 Site Information ' Sub Area Location: Drainage Area 2 Drainage Area (DA) = 24.40 Acres Impervious Area (IA) = 18.30 Acres ' Percent Impervious (1) = 75.0 % Required Surface Area Permanent Pool Depth: 4.35 ft ' SA/DA = 3.375 (90% TSS Removal via Pond) Min Req'd Surface Area = 35872 sf (at Permanent Pool) Required Storage Volume: ' Design Storm = 1 inch (Project Does Not Drain to SA waters) Determine Rv Value = 0.05 +. 009 (1) = 0.73 in/in Storage Volume Required = 64215 cf (above Permanent Pool) ' Elevations Area (s.f.) Bank Elevation = 725.00 ft Top of Pond Elevation = 725.00 ft ' Temporary Pool Elevation = 720.70 ft 39,312 Permanent Pool Elevation = 719.00 ft 36,315 Shelf Beginning Elevation = 719.50 ft ' Forebay Weir = 722.00 ft Shelf Ending Elevation = 718.50 ft Sediment Cleanout Elevation = 712.00 ft ' Bottom Elevation = 711.00 ft Wet Basin Areas/Volumes Area @ Top of Temporary Pool = 39312 sf (Elevation = 720.70) ' Area @ Top of Permanent Pool = 36315 sf (Elevation = 719.00) Volume of Temporary Storage = 64283 cf ' Side Slopes of Pond = 3 :1 Side Slopes of Shelf = 1 0 :1 Side Slopes of Pond (below shelf) = 3 :1 ' Is Permanent Pool Surface Area Sufficient (yes/no)? Yes ( 36315 > 35872) sf Volume of Storage Provided 64283 cf ' T l V l S ffi i ? ota o ume u c ent (yes/no) Yes Orifice Size = 2.80 inches ' 1 1 1 1 1 WET DETENTION BASIN Project Information Project Name: Belgate - Southern Tract KHA Project #: 018253026 Designed by: BRR Date: Revised by: BRR Date: Revised by: BRR Date: Site Information Sub Area Location: Drainage Area 2 Drainage Area (DA) = 24.40 Acres Impervious Area (IA) = 18.30 Acres Percent Impervious (1) = 75.0 % (Drainage Area) Orifice Sizing Q2 Days = 0.3707 cfs (Flowrate required for a 2 day drawdown) Q5 Days = 0.1483 cfs (Flowrate required for a 5 day drawdown) Orifice Size = 2.80 in (Diameter) Q Orifice = 0.150 cfS Drawdown Time = 5.0 days less than 5 days (yes/no) ? yes greater than 2 days (yes/no) ? yes Orifice Equation: Q=cAgV(2gh) Q2 < Q < Q5 c = 0.6 A9= Area of Pipe = Tr/4D2 g = gravity = 32.2 ft/s2 h = orifice head = 1/3 (TPE-PPE-1/2D) TPE = Temporary Pool Elevation PPE = Permanent Pool Elevation D = Diameter 10/19/2008 11/3/2008 11/14/2008 ANTI-FLOTATION DEVICE CALCULATIONS STORMWA TER MANAGEMENT CALCULATIONS ' South Tract City Boulevard Development, Charlotte, North Carolina 1? ® aM 0.uo7atea, lrc NCDENR ANTIFLOATATION DEVICE DESIGN CALCULATIONS (per NCDENR Manual) Project Information ' Project Name: Belgate - Southern Tract KHA Project #: 018253026 Designed by: BRR Date: 11/3/2008 Revised by: Date: Revised by: Date: ' Revised by: Date: 1 1 1 1 1 1 Drainage Area Information: Drainage Area (ac) = 7.15 Flow (Q.) (cfs) = 12.8 Storage Dimensions: Basin Side Slopes L : 1 ) = 3.0 Storage Depth "R" (ft) = 9.0 Top of Basin Elevation Temporary Pool Elevation Permanent Pool Elevation Bottom of Basin Elevation (3:1 max side slopes) Elev (ft) Area (SF) Cumulative Volume (CF) 732.00 27,972 730.00 23,807 124,239 727.70 16,459 77,934 726.00 11,541 54,134 723.00 7,735 25,220 720.00 3,846 7,848 717.00 1,386 0 Control Structure Length (in) = 48 Control Structure Width (in) = 36 Riser Area (sf) = 12.00 (Check riser geometry vs. area equation) Volume of Water Displaced (cf) = 108.0 Weight of Water Displaced (lb) = 6,739 Min. Required Weight of Anchor Block (lb) = 7,413 (1.1 factor of safety) Anchor Size: Width (If) = 4.4 Length (If) = 5.0 Height (If) = 4.00 Weight of Anchor (Ib) = 7,709 O.K. > Minimum Required Weight Sizing of Emergency Spillway: Qs, (cfs) = 12.8 Qsgnw. (cfs) = 12.8 (Riser ignored) Water Depth Over Spillway (ft) = 0.5 Spillway Length (ft) = 15.0 (10 ft minimum spillway length, Cw=2.7) Spillway Crest Elevation (ft) = 730.5 (1 ft min. above sediment storage depth) Freeboard (ft) = 1.04 (1 ft minimum) Page 1 of 1 IM "ey-K- ?? rM Assaoales, lnt. NCDENR ANTIFLOATATION DEVICE DESIGN CALCULATIONS (per NCDENR Manual) Project Information Project Name: Belgate - Southern Tract KHA Project #: 018253026 Designed by: BRR Date: 11/312008 Revised by: Date: Revised by: Date: Revised by: Date: Pond 2 Drainage Area Information: Drainage Area (ac) = 23.90 Flow (Q.) (cfs) = 16.7 Storage Dimensions: Basin Side Slopes (X : 1 ) = 3.0 Storage Depth "R" (ft) = 7.0 Top of Basin Elevation Temporary Pool Elevation Permanent Pool Elevation Bottom of Basin Elevation (3:1 max side slopes) Elev (ft) Area (SF) Cumulative Volume (CF) 725.00 60,143 723.00 53,616 332,340 720.70 39,312 225,473 719.00 31,750 165,071 716.00 22,055 84,363 714.00 17,794 44,514 711.00 11,882 0 Control Structure Length (in) = 48 Control Structure Width (in) = 36 Riser Area (sf) = 12.00 (Check riser geometry vs. area equation) Volume of Water Displaced (cf) = 96.0 Weight of Water Displaced (Ib) = 5,990 Min. Required Weight of Anchor Block (Ib) = 6,589 (1.1 factor of safety) Anchor Size: Width (If) = 4.1 Length (If) = 4.8 Height (If) = 4.00 Weight of Anchor (Ib) = 6,896 O.K. > Minimum Required Weight Sizing of Emergency Spillway: Q? (cfs) = 16.7 Q-0-, (cfs) = 16.7 (Riser ignored) Water Depth Over Spillway (ft) = 0.5 Spillway Length (ft) = 40.0 (10 ft minimum spillway length, Cw=2.7) Spillway Crest Elevation (ft) = 723.7 (1 ft min. above sediment storage depth) Freeboard (ft) = 1.01 (1 ft minimum) Page 1 of 1 I I C? 1 1 VOLUME AND SURFACE AREA TABLES ' STORMWATER MANAGEMENT CALCULATIONS South Tract City Boulevard Development, Charlotte, North Carolina m ° m ° o ai E i CD CD cc v O ? ° O a) ? ? ? V m co m F- Np a C M Q a) t I N a) co u p O U) n y Of m E 3 O c O O T m al O _O Z v v o _ u a m p Q v a) d L 2 O tY tr 'O CL Y a` C to co C O Y Q1 v a) E i lD N m e-I .-i lD 00 co Q 7 0 0 N e--I V N c r\ O1 00 O to V tD tD 0 a-i M l0 ci r+ N zt In rl m am a1 E N m N i.n lD ri N o N 7 U O O 1-1 1-1 zT 1-4 -1 Ln r It CO N . 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M W m Ln M rl a) E II p a) O a 7 N _O + ,+ Ln c a) 0 c o p c p N m m c ro a) w co a 1 1 1 1 1 1 WET DETENTION BASIN SUPPLEMENT FORMS STORMWA TER MANAGEMENT CALCULATIONS South Tract Cite Boulevard Development, Charlotte, North Carolina ' Permit No. (to be provided by DWQ) 7 J 7 7 1 1 i 1 u ? ?pF W ATFj, `?ygT G p? G T NCDENR STORMWATER MANAGEMENT PERMIT APPLICATION FORM 401 CERTIFICATION APPLICATION FORM WET DETENTION BASIN SUPPLEMENT This form must be filled out, printed and submitted. The Required Items Checklist (Part Ill) must be printed, filled out and submitted along with all of the required information. I. PROJECT INFORMATION Project name Belgate Southern Tract Contact person Beverly Rosenbloom, El Phone number 704-319-7699 Date 11/17/2008 Drainage area number 1 II. DESIGN INFORMATION Site Characteristics Drainage area 311,454.00 ft2 Impervious area 280,090.80 ff % impervious 89.93 % Design rainfall depth 1.00 in Storage Volume: Non-SR Waters Minimum volume required 22,305.00 ft3 Volume provided 25,227.00 ft3 Storage Volume: SR Waters 1-yr, 24-hr runoff depth in Pre-development 1-yr, 24-hr runoff ft 3 Post-development 1-yr, 24-hr runoff ft 3 Minimum volume required ft 3 Volume provided ft3 Peak Flow Calculations 1-yr, 24-hr rainfall depth 2.58 in Rational C, pre-development 0.28 (unitless) Rational C, post-development 0.88 (unitless) Rainfall intensity: 1-yr, 24-hr storm 0.12 in/hr Pre-development 1-yr, 24-hr peak flow 2.63 ft3/sec Post-development 1-yr, 24-hr peak flow 9.25 ft3/sec Pre/Post 1-yr, 24-hr peak flow control 6.62 ft3/sec Basin Elevations Basin bottom elevation 717.00 ft Sediment cleanout elevation 718.00 ft Bottom of shelf elevation 725.50 ft Permanent pool elevation 726.00 ft SHWT elevation 712.00 ft Top of shelf elevation 726.50 ft Temporary pool elevation 727.70 ft 1 Form SW401-Wet Detention Basin-Rev.4 Parts I. & II. Design Summary, Page 1 of 2 I n 1 7 1 Permit No. (to be provided by DWQ) II. DESIGN INFORMATION Volume and Surface Area Calculations SA/DA ratio 4.00 (unitless) Surface area at the bottom of shelf 8,955.00 rye Volume at the bottom of shelf 42,518.00 ft3 Permanent pool, surface area required 12,458.00 ft2 Permanent pool, surface area provided 13,220.00 ft2 OK Permanent pool volume 53,233.00 ft3 Average depth for SA/DA tables 4.03 ft OK Surface area at the top of shelf 14,328.00 ft2 Volume at the top of shelf 54,109.00 ff3 Forebay volume 9,668.00 ft3 Forebay % of permanent pool volume 18.16 % OK Temporary pool, surface area provided 16,459.00 ft2 Drawdown Calculations Treatment volume drawdown time 2.90 days OK Treatment volume discharge rate 0.10 ft3/s Pre-development 1-yr, 24-hr discharge 2.63 ft3/s OK Post-development 1-yr, 24-hr discharge 1.76 ft3/s OK Additional Information Diameter of orifice 2.3 in Design TSS removal 90 % Basin side slopes 3.00 :1 OK Vegetated shelf slope 10.00 :1 OK Vegetated shelf width 10.00 ft OK Length of flowpath to width ratio 4.40 :1 OK Length to width ratio 3.30 :1 OK Trash rack for overflow & orifice? Y (Y or N) OK Freeboard provided 2.25 ft OK Vegetated filter provided? N (Y or N) Design must be based on 90% TSS removal Recorded drainage easement provided? Y (Y or N) OK Capures all runoff at ultimate build-out? Y (Y or N) OK Drain mechanism for maintenance or emergencies 24-HR EMERGENCY PUMP 1 1 1 1 Form SW401-Wet Detention Basin-Rev.4 Parts I. & II. Design Summary, Page 2 of 2 Permit (to be provided by DWQ) 111. REQUIRED ITEMS CHECKLIST i j Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will result in a request for additional information. This will delay final review and approval of the project. Initial in the space provided to indicate the following design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a requirement has not been met, attach justification. Page/ Plan Initials Sheet No. ' _C-3 1. Plans (1" 50' or larger) of the entire site showing: Design at ultimate build-out, Off-site drainage (if applicable), ' Delineated drainage basins (include Rational C coefficient per basin), Basin dimensions, Pretreatment system, High flow bypass system, Maintenance access, Proposed drainage easement and public right of way (ROW), ' Overflow device, and Boundaries of drainage easement. ' 9 C-4 2. Partial plan (1 " = 30' or larger) and details for the wet detention basin showing: Outlet structure with trash rack or similar, Maintenance access, Permanent pool dimensions, ' Forebay and main pond with hardened emergency spillway, Basin cross-section, Vegetation specification for planting shelf, and Filter strip. Z? tx- C-4 3. Section view of the dry detention basin (1" = 20' or larger) showing: Side slopes, 3:1 or lower, ' Pretreatment and treatment areas, and Inlet and outlet structures. ' ID DIt- C-3 4. If the basin is used for sediment and erosion control during construction, clean out of the basin is specified on the plans prior to use as a wet detention basin. dcg C-4 5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay, to verify volume provided. ' ?164"t Attached 6. A construction sequence that shows how the wet detention basin will be protected from sediment until the entire drainage area is stabilized. ' - _Calc book- 7. The supporting calculations. -Attached- 8. A copy of the signed and notarized operation and maintenance (0&M) agreement. ' -K -Attached- 9. A copy of the deed restrictions (if required). KX, -Attached- 10. A soils report that is based upon an actual field investigation, soil borings, and infiltration tests. County soil maps are not an acceptable source of soils information. Form SW401-Wet Detention Basin-Rev.4 Part III. Required Items Checklist, Page 1 of 1 Permit No. (to be provided by DWQ) MARIA F W ATec NCDENR STORMWATER MANAGEMENT PERMIT APPLICATION FORM 401 CERTIFICATION APPLICATION FORM WET DETENTION BASIN SUPPLEMENT This form must be filled out, printed and submitted. The Required Items Checklist (Part 111) must be printed, filled out and submitted along with all of the required information. I P O . JECT INFORMATION R Project name Belgate Southern Tract Contact person Beverly Rosenbloom, El ' Phone number 704-319-7699 Date 11/17/2008 ' Drainage area number 2 II DESIGN INFORMATI N . O Site Characteristics Drainage area 1,062,864.00 ffz ' Impervious area 797,148.00 ft2 % impervious 75.00 % Design rainfall depth 1.00 in Storage Volume: Non-SR Waters Minimum volume required 64,215.00 ff3 Volume provided 64,238.00 ft3 ' Storage Volume: SR Waters 1-yr, 24-hr runoff depth in Pre-development 1-yr, 24-hr runoff ft3 Post-development 1-yr, 24-hr runoff ft3 Minimum volume required ff3 Volume provided ft3 Peak Flow Calculations ' 1-yr, 24-hr rainfall depth 2.58 in Rational C, pre-development 0.28 (unitless) Rational C, post-development 0.79 (unitless) Rainfall intensity: 1-yr, 24-hr storm 0.12 in/hr Pre-development 1-yr, 24-hr peak flow 1.57 ft3/sec Post-development 1-yr, 24-hr peak flow 24.36 ft3/sec Pre/Post 1-yr, 24-hr peak flow control 22.79 ft3/sec Basin Elevations Basin bottom elevation 711.00 ft Sediment cleanout elevation Bottom of shelf elevation 712.00 ft 718.50 ft Permanent pool elevation 719.00 ft SHWT elevation 708.00 ft Top of shelf elevation 719.50 ft Temporary pool elevation 720.70 ft 1 I Form SW401-Wet Detention Basin-Rev.4 Parts I. & II. Design Summary, Page 1 of 2 i Permit N (to be provided by DWQ) II. DESIGN INFORMATION Volume and Surface Area Calculations SA/DA ratio 3.38 (unitless) Surface area at the bottom of shelf 27,740.00 ft2 Volume at the bottom of shelf 133,518.00 ft3 Permanent pool, surface area required 35,872.00 ft2 Permanent pool, surface area provided 36,315.00 ft2 OK Permanent pool volume 158,718.00 ft3 Average depth for SAW tables 4.37 ft OK Surface area at the top of shelf 35,931.00 ff Volume at the top of shelf 165,311.00 ft3 Forebay volume 28,816.00 ft3 Forebay % of permanent pool volume 18.16 % OK Temporary pool, surface area provided 29,312.00 ff2 Drawdown Calculations Treatment volume drawdown time 5.00 days OK Treatment volume discharge rate 0.15 ft3/s Pre-development 1-yr, 24-hr discharge 1.57 ft3/s OK Post-development 1-yr, 24-hr discharge 1.50 ft3/s OK Additional Information Diameter of orifice 2.8 in Design TSS removal 90 % Basin side slopes 3.00 :1 OK Vegetated shelf slope 10.00 :1 OK Vegetated shelf width 10.00 ft OK Length of flowpath to width ratio 4.10 :1 OK Length to width ratio 3.20 :1 OK Trash rack for overflow & orifice? Y (Y or N) OK Freeboard provided 1.40 ft OK Vegetated filter provided? N (Y or N) Design must be based on 90% TSS removal Recorded drainage easement provided? Y (Y or N) OK Capures all runoff at ultimate build-out? Y (Y or N) OK Drain mechanism for maintenance or emergencies 24-HR EMERGENCY PUMP Form SW401-Wet Detention Basin-Rev.4 Parts I. & II. Design Summary, Page 2 of 2 ' Permit No. (to be provided by DWQ) IIII LJ? IIL REQUIRED ITEMS CHECKLIST Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will result in a request for additional information. This will delay final review and approval of the project. Initial in the space provided to indicate the following design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a requirement has not been met, attach justification. Page/ Plan ' Initials Sheet No. 7" C3 0 1 IJ 1 Plans (1" - 50' or larger) of the entire site showing: Design at ultimate build-out, Off-site drainage (if applicable), Delineated drainage basins (include Rational C coefficient per basin), Basin dimensions, Pretreatment system, High flow bypass system, Maintenance access, Proposed drainage easement and public right of way (ROW), Overflow device, and Boundaries of drainage easement. _C-4 2. Partial plan (1 30' or larger) and details for the wet detention basin showing: Outlet structure with trash rack or similar, Maintenance access, Permanent pool dimensions, Forebay and main pond with hardened emergency spillway, Basin cross-section, Vegetation specification for planting shelf, and Filter strip. 6" C-4 3. Section view of the dry detention basin (1" = 20' or larger) showing Side slopes, 3:1 or lower, Pretreatment and treatment areas, and Inlet and outlet structures. _C-3 4. If the basin is used for sediment and erosion control during construction, clean out of the basin is specified on the plans prior to use as a wet detention basin. 19 C-4 5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay, to verify volume provided. 6. A construction sequence that shows how the wet detention basin will be protected from sediment until the entire drainage area is stabilized. _Calc book- 7. The supporting calculations. -Attached- 8. A copy of the signed and notarized operation and maintenance (0&M) agreement. ' -Attached- 9. A copy of the deed restrictions (if required). -Attached- 10. A soils report that is based upon an actual field investigation, soil borings, and infiltration tests. County soil maps are not an acceptable source of soils information. Form SW401-Wet Detention Basin-Rev.4 Part III. Required Items Checklist, Page 1 of 1 u 0 CURVE NUMBER CALCULATIONS J1 V11111 r"1GIC "I'll' 1-11-111J-'1V1 GALCULAIIUNI? ' South Tract City Boulevard Development, Charlotte, North Carolina 1 1 1 1 ?ISR Kim ley-Horn CIM" and Associates, inc. Pre vs. Post Runoff Analysis Composite Curve Number (CN) Project Information Project Name: Southern Tract KHA Project #: 018253026 Designed by: BRR Revised by: BRR Revised by: Date: 10/6/2008 Date: 11/14/2008 Date: Drainage Area Name Drainage Location Cover/Soil Name (Type) Cover Description' Hydrologic Soil Group Curve # (CN)" Area (ac) Product of CN x area Composite Curve Number (CN) PRE-DEVELOPMENT DA-1 OUTFALL 1 Mecklenburg, Enon, Wilkes Woods Good Condition C 70 5.04 353 70 Meadow Good Condition B 71 5.04 358 71 10.08 711 70.5 DA-2 OUTFALL 1 Mecklenburg, Enon, Wilkes Woods Good Condition C 70 2.95 207 70 Mecklenburg, Enon, Wilkes Meadow Good Condition C 71 2.95 209 71 Cecil Meadow Good Condition B 58 10.69 620 58 Cecil Woods Good Condition B 55 10.69 588 55 27.28 1624 59.5 Total Pre-development Area = 37.36 POST DEVELOPMENT DA-1 POND 1 Impervious 98 6.43 631 98 Mecklenburg, Enon, Wilkes Open Space - Good Condition C 74 0.71 53 74 7.15 683.46 95.60 UND DA-1 OUTFALL 1 Mecklenburg, Enon, Wilkes Open Space - Good Condition C 74 1.15 85 74 1015 85.10 74.00 DA-2 POND 2 Impervious 98 15.40 1509 98 Mecklenburg, Enon, Wilkes Open Space - Good Condition C 74 0.83 61 74 Cecil Open Space - Good Condition B 61 4.11 251 61 Roadway - Impervious 98 2.90 264 98 Mecklenburg, Enon, Wilkes Roadway- Open Space C 74 1.06 78 74 Cecil Roadway - Open Space B 61 0.10 6 61 24.40 2190.07 89.76 UND DA-2 OUTFALL 2 Mecklenburg, Enon, Wilkes Open Space - Good Condition C 74 2.96 F 219 74 Cecil Open Space - Good Condition B 61 2.97 181 61 i I 5.93 400.21 67.49 Total Post-development Area = 38.63 Cover Descriptions per TR-55 Manual " From TR-55 Manual, Table 2-2 a & c K:\CHL_LDEV\018253 Crescent\026 Belgate\Belgate Stormwater Management Plan\Calculations\Parcel J\Stormwater Calculations_2008-10-06.xls 1 of 1 TIME OF CONCENTRATION ' CALCULATIONS 1 1 1 EROSION CONTROL CALCULATIONS ' New Towne Gardens, Union County, North Carolina r 1.1 1 1 1 1 1 1 1 1 1 1 ' zg /'': 1 ? N T C iC O C w Q ? O d C ? O .• U O O a d > E d ~ IL °o N O O U co m ? ? ? U H m L m co E o CO 0 '0 Z d o c CD > '> c d 2 O O Y E 0 C U m ` a ? N 11 o N N to N N N wi N o a II C ? a v II C ? v cd F c co F C O C O r C m U c O O O C m U o O CD U o U O o F- F N LD Ci Cl) O c0 N m N_ of C; 0 m 0 o O O N O m O v O a> O o c°o m ii m o m m cN'> u? .a 0 d C U o 0 0 o N C t C> 0 7 U 3 C? 3 ( 7 m > C U 3t a 1 > m Z m Z 3 l0 N 3 R N U) t v (n C L U) t U (n C L O U U O U U Q Q O p Q LL Q LL D O O Q N Q O p F - z W a 0 w W ? W a a O 11 HYDROCAD HYDROLOGY REPORT 1 EROSION CONTROL CALCULATIONS New Towne Gardens, Union County, North Carolina 1S 2S 4S Pre-dev DA-1 Post-d v DA-1 Post-dev ND DA-1 ';7 17 3P 8P Pond 1 Outfall 1 8S (5S (6S ) () Pre-dev DA-2 Post-d v DA-2 Post-dev ND DA-2 7P 9P Pond 2 Outfall 2 Subca Reach on Lin k 0 1 Southern Tract SWMP Charlotte 24-hr 1-yr 24.00 hrs 1 yr - 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 11/17/2008 HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Paae 2 Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment 1S: Pre-dev DA-1 Runoff Area=10.080 ac 0.00% Impervious Runoff Depth>0.53" Tc=25.2 min CN=71 Runoff=2.63 cfs 0.443 of Subcatchment 2S: Post-dev DA-1 Runoff Area=7.150 ac 0.00% Impervious Runoff Depth>2.14" Tc=5.0 min CN=96 Runoff=9.25 cfs 1.274 of Subcatchment 4S: Post-dev UND DA -11 Runoff Area=1.150 ac 0.00% Impervious Runoff Depth>0.65" Tc=5.0 min CN=74 Runoff=0.47 cfs 0.063 of Subcatchment 5S: Pre-dev DA-2 Runoff Area=27.280 ac 0.00% Impervious Runoff Depth>0.19" Tc=25.0 min CN=60 Runoff=1.57 cfs 0.441 of Subcatchment 6S: Post-dev DA-2 Runoff Area=24.400 ac 0.00% Impervious Runoff Depth>1.52" Tc=5.0 min CN=89 Runoff=24.36 cfs 3.098 of Subcatchment 8S: Post-dev UND DA-2 Runoff Area=5.930 ac 0.00% Impervious Runoff Depth>0.39" Tc=5.0 min CN=67 Runoff=1.27 cfs 0.193 of Pond 3P: Pond 1 Peak EIev=728.07' Storage=34,871 cf Inflow=9.25 cfs 1.274 of Outflow=1.64 cfs 0.604 of Pond 7P: Pond 2 Peak EIev=721.78' Storage=120,963 cf Inflow=24.36 cfs 3.098 of Outflow=0.34 cfs 0.321 of Pond 8P: Outfall 1 Inflow=1.76 cfs 0.667 of Primary=1.76 cfs 0.667 of Pond 9P: Outfall 2 Inflow=1.50 cfs 0.514 of Primary=1.50 cfs 0.514 of Total Runoff Area = 75.990 ac Runoff Volume = 5.511 of Average Runoff Depth = 0.87" 100.00% Pervious = 75.990 ac 0.00% Impervious = 0.000 ac Southem Tract SWMP Charlotte 24-hr 1-yr 24.00 hrs 1 yr - 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 11/17/2008 HydroCADO 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Paoe 3 ' Summary for Subcatchment 1S: Pre-dev DA-1 ' Runoff = 2.63 cfs @ 12.77 hrs, Volume= 0.443 af, Depth> 0.53" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Charlotte 24-hr 1-yr 24.00 hrs 1 yr - 24 hr Rainfall=2.58" Area (ac) CN Description 10.080 71 10.080 Pervious Area Tc Length Slope Velocity Capacity Description ' (min) (feet) (ft/ft) (ft/sec) (cfs) 25.2 Direct Entry, From spreadsheet Subcatchment 1S: Pre-dev DA-1 Hydrograph w 3 0 U. u 11 ¦ Runoff 11 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) 1 ' Southern Tract SWMP Charlotte 24-hr 1-yr 24.00 hrs 1 yr - 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 11/17/2008 HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Paoe 4 Summary for Subcatchment 2S: Post-dev DA-1 1 1 [49] Hint: Tc<2dt may require smaller dt Runoff = 9.25 cfs @ 12.40 hrs, Volume= 1.274 af, Depth> 2.14" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Charlotte 24-hr 1-yr 24.00 hrs 1 yr - 24 hr Rainfall=2.58" Area (ac) CN Description 7.150 96 7.150 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, From spreadsheet 1 N w V O LL 1 1 Subcatchment 2S: Post-dev DA-1 Hydrograph ¦ Runoff 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) Southem Tract SWMP Charlotte 24-hr 1-yr 24.00 hrs 1 yr- 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 11/17/2008 HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 5 ' Summary for Subcatchment 4S: Post-dev UND DA-1 ' [49] Hint: Tc<2dt may require smaller dt Runoff = 0.47 cfs @ 12.45 hrs, Volume= 0.063 af, Depth> 0.65" ' Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Charlotte 24-hr 1-yr 24.00 hrs 1 yr - 24 hr Rainfall=2.58" Area (ac) CN Description 1.150 74 1.150 Pervious Area F 1 1 Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, N V O LL 11 1 1 Subcatchment 4S: Post-dev UND DA-1 Hydrograph ¦ Runoff C 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) ' Southem Tract SWMP Charlotte 24-hr 1-yr 24.00 hrs 1 yr - 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 11/17/2008 HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 6 Summary for Subcatchment 5S: Pre-dev DA-2 Runoff = 1.57 cfs @ 13.04 hrs, Volume= 0.441 af, Depth> 0.19" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Charlotte 24-hr 1-yr 24.00 hrs 1 yr - 24 hr Rainfall=2.58" Area (ac) CN Description 27.280 60 ' 27.280 Pervious Area Tc Length Slope Velocity Capacity Description ' (min) (feet) (ft/ft) (ft/sec) (cfs) 25.0 Direct Entry, From Spreadsheet Subcatchment 5S: Pre-dev DA-2 Hydrograph 1 a 3 0 U. 1 1 ¦ Runoff 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) i Southem Tract SWMP Charlotte 24-hr 1-yr 24.00 hrs 1 yr- 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 11/17/2008 HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Paoe 7 Summary for Subcatchment 6S: Post-dev DA-2 [49] Hint: Tc<2dt may require smaller dt Runoff = 24.36 cfs @ 12.41 hrs, Volume= 3.098 af, Depth> 1.52" ' Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Charlotte 24-hr 1-yr 24.00 hrs 1 yr - 24 hr Rainfall=2.58" Area (ac) CN Description 24.400 89 24.400 Pervious Area 1 Tc Length Slope Velocity Capacity Description (min) (feet) (fUft) (ft/sec) (cfs) 5.0 Direct Entry, H V ' O LL r Subcatchment 6S: Post-dev DA-2 Hydrograph ¦ Runoff 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) Southem Tract SWMP Charlotte 24-hr 1-yr 24.00 hrs 1 yr - 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 11/17/2008 HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 8 Summary for Subcatchment 8S: Post-dev UND DA-2 [49] Hint: Tc<2dt may require smaller dt Runoff = 1.27 cfs @ 12.50 hrs, Volume= 0.193 af, Depth> 0.39" ' Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Charlotte 24-hr 1-yr 24.00 hrs 1 yr - 24 hr Rainfall=2.58" ' Area (ac) CN Description 5.930 67 5.930 Pervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Subcatchment 8S: Post-dev UND DA-2 Hydrograph ', ' ', ', ' ' ' ' I I ¦ Runoff 1.27 cfs Charlotte 24' ht 1-W 24.00hrs 1 yr - 24 hr ----------- ------- -- ----- --- ---- -------- - ----- -------- -------- ------- Rainfall==2'58" Runoff Area=5:930 ac: Runoff Volum:e' =0.1 03: at LL Runoff Depth>0.39'" 1`c=5.0 mile CN =67 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) Southern Tract SWMP Charlotte 24-hr 1-yr 24.00 hrs 1 yr - 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 11/17/2008 HydroCAM 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 9 Summary for Pond 3P: Pond 1 Inflow Area = 7.150 ac, 0.00% Impervious, Inflow Depth > 2.14" for 1 yr - 24 hr event Inflow 9.25 cfs @ 12.40 hrs, Volume= 1.274 of Outflow = 1.64 cfs @ 13.37 hrs, Volume= 0.604 af, Atten= 82%, Lag= 58.0 min ' Primary = 1.64 cfs @ 13.37 hrs, Volume= 0.604 of Routing by Stor-In d method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Peak Elev= 728.07'@ 13.37 hrs Surf.Area= 19,585 sf Storage= 34,871 cf Plug-Flow detention time= 287.4 min calculated for 0.603 of (47% of inflow) Center-of-Mass det. time= 169.2 min ( 960.9 - 791.7 ) Volume Invert Avail.Storage Storage Description #1 726.00' 128,745 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 726.00 13,220 0 0 727.00 17,234 15,227 15,227 ' 728.00 19,423 18,329 33,556 729.00 21,832 20,628 54,183 730.00 23,807 22,820 77,003 731.00 25,853 24,830 101,833 732.00 27,972 26,913 128,745 Device Routing Invert Outlet Devices #1 Primary 726.00' 36.0" x 51.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 725.00' S=0.0196'/' Cc= 0.900 n=0.013 #2 Device 1 726.00' 2.3" Vert. Orifice/Grate C= 0.600 #3 Device 1 727.75' 2.50' W x 0.75'H Vert. Orifice/Grate C=0.600 #4 Device 1 729.00' 2.50' W x 0.67'H Vert. Orifice/Grate C=0.600 #5 Device 1 729.50' 3.00' x 4.00' Horiz. Orifice/Grate Limited to weir flow C=0.600 Primary OutFlow Max=1.63 cfs @ 13.37 hrs HW=728.07' (Free Discharge) L7=Culvert (Passes 1.63 cfs of 25.43 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.20 cfs @ 6.76 fps) 3=Orifice/Grate (Orifice Controls 1.43 cfs @ 1.81 fps) -Orifice/Grate ( Controls 0.00 cfs) -Orifice/Grate ( Controls 0.00 cfs) 1 1 l 11 1 Southern Tract SWMP Charlotte 24-hr 1-yr 24.00 hrs 1 yr- 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 11/17/2008 HydroCAM 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 10 Pond 3P: Pond 1 Hydrograph 1 N V 3 O LL ¦ Inflow ¦ Primary 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) J Southern Tract SWMP Charlotte 24-hr 1-yr 24.00 hrs 1 yr - 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 11/17/2008 HydroCAD® 8.50 s/n 005123 © 2007 HydroCAD Software Solutions LLC Paoe 11 Summary for Pond 7P: Pond 2 Inflow Area 24.400 ac, 0.00% Impervious, Inflow Depth > 1.52" for 1 yr - 24 hr event Inflow 24.36 cfs @ 12.41 hrs, Volume= 3.098 of Outflow = 0.34 cfs @ 24.00 hrs, Volume= 0.321 af, Atten= 99%, Lag= 695.4 min Primary = 0.34 cfs @ 24.00 hrs, Volume= 0.321 of Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Peak Elev= 721.78' @ 24.00 hrs Surf.Area= 49,081 sf Storage= 120,963 cf Plug-Flow detention time= 435.9 min calculated for 0.320 of (10% of inflow) Center-of-Mass det. time= 253.2 min ( 1,084.4 - 831.2 ) Volume Invert Avail.Storage Storage Description #1 719.00' 297,453 cf Custom Stage Data (Prismatic) Listed below (Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 719.00 36,315 0 0 720.00 42,648 39,482 39,482 721.00 46,208 44,428 83,910 722.00 49,902 48,055 131,965 723.00 53,616 51,759 183,724 724.00 56,850 55,233 238,957 725.00 60,143 58,497 297,453 Device Routing Invert Outlet Devices #1 Primary 719.00' 36.0" x 147.0' long Culvert RCP, square edge headwall, Ke= 0.500 Outlet Invert= 716.00' S=0.0204'/' Cc= 0.900 n=0.013 #2 Device 1 719.00' 2.8" Vert. Orifice/Grate C= 0.600 #3 Device 1 723.60' 4.00' x 3.00' Horiz. Orifice/Grate Limited to weir flow C=0.600 #4 Device 1 722.00' 1.50' W x 0.50'H Vert. Orifice/Grate C=0.600 Primary OutFlow Max=0.34 cfs @ 24.00 hrs HW=721.78' (Free Discharge) L1=Culvert (Passes 0.34 cfs of 38.77 cfs potential flow) 2=Orifice/Grate (Orifice Controls 0.34 cfs @ 7.85 fps) 3=Orifice/Grate ( Controls 0.00 cfs) -Orifice/Grate ( Controls 0.00 cfs) 11 Fi Southern Tract SWMP Charlotte 24-hr 1-yr 24.00 hrs 1 yr - 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 11/17/2008 HydroCAD® 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 12 Pond 7P: Pond 2 Hydrograph ¦ Inflow ¦ Primary N V 3 O U. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) 1 Southern Tract SWMP Charlotte 24-hr 1-yr 24.00 hrs 1 yr - 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 11/17/2008 HydroCADO 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Page 13 Summary for Pond 8P: Outfall 1 [40] Hint: Not Described (Outflow=Inflow) Inflow Area = 8.300 ac, 0.00% Impervious, Inflow Depth > 0.96" for 1 yr - 24 hr event Inflow = 1.76 cfs @ 13.31 hrs, Volume= 0.667 of Primary = 1.76 cfs @ 13.31 hrs, Volume= 0.667 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Pond 8P: Outfall 1 Hydrograph N V ' O U. ¦ Inflow ¦ Primary 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours) 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Southern Tract SWMP Charlotte 24-hr 1-yr 24.00 hrs 1 yr- 24 hr Rainfall=2.58" Prepared by Kimley-Horn and Associates, Inc. Printed 11/17/2008 HydroCADO 8.50 s/n 005123 @2007 HydroCAD Software Solutions LLC Paae 14 Summary for Pond 9P: Outfall 2 [40] Hint: Not Described (OutFlow=Inflow) Inflow Area = 30.330 ac, 0.00% Impervious, Inflow Depth > 0.20" for 1 yr - 24 hr event Inflow = 1.50 cfs @ 12.51 hrs, Volume= 0.514 of Primary = 1.50 cfs @ 12.51 hrs, Volume= 0.514 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Pond 9P: Outfall 2 Hydrograph N O 3 O LL ¦ Inflow ¦ Primary 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Time (hours)