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HomeMy WebLinkAboutSW8071203_HISTORICAL FILE_20071206STORMWATER DIVISION CODING SHEET POST -CONSTRUCTION PERMITS PERMIT NO. SW8 0-1%Z o 3 DOC TYPE ❑ CURRENT PERMIT ❑ APPROVED PLANS Fo HISTORICAL FILE ❑ COMPLIANCE EVALUATION INSPECTION DOC DATE ZUoZ 12A\.n YYYYMMDD Michael F. Easley, Governor William G. Ross Jr., Secretary North Carolina Department of Environment and Natural Resources Coleen H. Sullins Director Division of Water Quality December 6, 2007 Todd Best, Manager of Facilities and Maintenance GE Hitachi Nuclear Energy 3901 Castle Hayne Road Wilmington< NC 28401 Subject: Permit No. SW8 071203 GE —Tooling Repair Center Low Density Stormwater Project New Hanover County Dear Mr. Best: The Wilmington Regional Office received a complete Stormwater Management Permit Application for the modification of GE — Tooling Repair Center on December 3, 2007. Staff review of the plans and specifications has determined that the project, as proposed, will comply with the Stormwater Regulations set forth in.Title 15A NCAC 2H.1000 and Session Law 2006-246. We are forwarding Permit No. SW8 071003 dated December 6, 2007, for the construction of the subject project. This permit shall be effective from the date of issuance until December 3, 2007, and shall be subject to the conditions and limitations as specified therein. Please pay special attention to the Operation and Maintenance requirements in this permit. Failure to establish an adequate system for operation and maintenance of the stormwater management system will result in future compliance problems. If any parts, requirements, or limitations contained in this permit are unacceptable, you have the right to request an adjudicatory hearing upon written request within sixty (60) days following receipt of this permit. This request must be in the form of a written petition, conforming to Chapter 150E of the North Carolina General Statutes, and filed with the Office of Administrative Hearings, P.O. Drawer 27447, Raleigh, NC 27611-7447. Unless such demands are made this permit shall be final and binding. If you have any questions, or need additional information concerning this matter, please contact Chris Baker, or me at (910) 796-7215. Since y, �C'4� Edward Beck Regional Supervisor Surface Water Protection Section ENB/csb: S:\WOS\STORMWATER\PERMIT\071203.dec07 cc: Mark Hargrove, P.E., Withers and Ravenel New Hanover County Building Inspections City of Wilmington Development Services New Hanover County Engineering Chris Baker C:__Wilmington_RegionalOffice Central Files --" N���`nnCarolina dVaturall1l North Carolina Division of Water Quality 127 Cardinal Drive Extension Wilmington, NC 28405 Phone (910) 796-7215 Customer Service Wilmington Regional Office Internet: vvim newaterqualiyy,nra Fax (910)350-2004 1-877-623-6748 An Equal Opportunity/Affirmative Action Employer — 50 % Recycled110 % Post Consumer Paper State Stormwater Management Systems Permit No. SW8 071203 STATE OF NORTH CAROLINA DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES DIVISION OF WATER QUALITY STATE STORMWATER MANAGEMENT PERMIT HIGH DENSITY DEVELOPMENT In accordance with the provisions of Article 21 of Chapter 143, General Statutes of North Carolina as amended, and other applicable Laws, Rules, and Regulations PERMISSION IS HEREBY GRANTED TO Todd Best and GE Hitachi Nuclear Energy GE — Tooling Repair Center 3901 Castle Hayne Road, New Hanover County FOR THE construction, operation and maintenance of a wet detention pond in compliance with the provisions of 15A NCAC 2H .1000 (hereafter referred to as the "stormwater rules') and the approved stormwater management plans and specifications and other supporting data as attached and on file with and approved by the Division of Water Quality and considered a part of this permit. This permit shall be effective from the date of issuance until December 3, 2007, and shall be subject to the following specified conditions and limitations: I. DESIGN STANDARDS This permit is effective only with respect to the nature and volume of stormwater described in the application and other supporting data. 2. This stormwater system has been approved for the management of stormwater runoff as described in Section 1.6 on page 3 of this permit. The stormwater control has been designed to handle the runoff from 568,702 square feet of impervious area. 3. The tract will be limited to the amount of built -upon area indicated on page 3 of this permit, and per approved plans. All stormwater collection and treatment systems must be located in either dedicated common areas or recorded easements. The final plats for the project will be recorded showing all such required easements, in accordance with the approved plans. The runoff from all built -upon area within the permitted drainage area of this project must be directed into the permitted stormwater control system. Page 2 of 7 State Stormwater Management Systems Permit No. SW8 071203 6. The following design criteria have been provided in the wet detention pond and must be maintained at design condition: a. Drainage Area, acres: Onsite, ft : Offsite, ft2: b. Total Impervious Surfaces, ft2: C. Design Storm, inches: d. Pond Depth, feet: e. TSS removal efficiency: f. Permanent Pool Elevation, FMSL: g. Permanent Pool Surface Area, ft2: h. Permitted Storage Volume, ft3: i. Temporary Storage Elevation, FMSL: j. Controlling Orifice: k. Permitted Forebay Volume, ft3: I. Fountain Horsepower, HP M. Receiving Stream/River Basin: n. Stream Index Number: o. Classification of Water Body: II. SCHEDULE OF COMPLIANCE 19.2 836,327 None 568,702 1.5 9 90% 25 42,439 71,109 26.5 4" 0 pipe 44,598 3/4 Prince George Creek / Cape Fear 18-74-53 "C; Sw,, 1. The stormwater management system shall be constructed in its entirety, vegetated and operational for its intended use prior to the construction of any built -upon surface. 2. During construction, erosion shall be kept to a minimum and any eroded areas of the system will be repaired immediately. 3. The permittee shall at all time provide the operation and maintenance necessary to assure the permitted stormwater system functions at optimum efficiency. The approved Operation and Maintenance Plan must be followed in its entirety and maintenance must occur at the scheduled intervals including, but not limited to: a. Semiannual scheduled inspections (every 6 months). b. Sediment removal. C. Mowing and re -vegetation of slopes and the vegetated filter. d. Immediate repair of eroded areas. e. Maintenance of all slopes in accordance with approved plans and specifications. f. Debris removal and unclogging of outlet structure, orifice device, flow spreader, catch basins and piping. g. Access to the outlet structure must be available at all times. Page 3 of 7 State Stormwater Management Systems Permit No. SW8 071203 4. Records of maintenance activities must be kept and made available upon request to authorized personnel of DWQ. The records will indicate the date, activity, name of person performing the work and what actions were taken. 5. Decorative spray fountains will be allowed in the stormwater treatment system, subject to the following criteria: a. The fountain must draw its water from less than 2' below the permanent pool surface. b. Separated units, where the nozzle, pump and intake are connected by tubing, may be used only if they draw water from the surface in the deepest part of the pond. c. The falling water from the fountain must be centered in the pond, away from the shoreline. d. The maximum horsepower for a fountain in this pond is 3/4 horsepower. 6. The facilities shall be constructed as shown on the approved plans. This permit shall become void unless the facilities are constructed in accordance with the conditions of this permit, the approved plans and specifications, and other supporting data. 7. Upon completion of construction, prior to issuance of a Certificate of Occupancy, and prior to operation of this permitted facility, a certification must be received from an appropriate designer for the system installed certifying that the permitted facility has been installed in accordance with this permit, the approved plans and specifications, and other supporting documentation. Any deviations from the approved plans and specifications must be noted on the Certification. A modification may be required for those deviations. 8. If the stormwater system was used as an Erosion Control device, it must be restored to design condition prior to operation as a stormwater treatment device, and prior to occupancy of the facility. 9. Access to the stormwater facilities shall be maintained via appropriate easements at all times. 10. The permittee shall submit to the Director and shall have received approval for revised plans, specifications, and calculations prior to construction, for any modification to the approved plans, including, but not limited to, those listed below: a. Any revision to any item shown on the approved plans, including the stormwater management measures, built -upon area, details, etc. b. Project name change. C. Transfer of ownership. d. Redesign or addition to the approved amount of built -upon area or to the drainage area. e. Further subdivision, acquisition, lease or sale of all or part of the project area. The project area is defined as all property owned by the permittee, for which Sedimentation and Erosion Control Plan approval or a CAMA Major permit was sought. f. Filling in, altering, or piping of any vegetative conveyance shown on the approved plan. 11. The permittee shall submit final site layout and grading plans for any permitted future areas shown on the approved plans, prior to construction. 12. A copy of the approved plans and specifications shall be maintained on file by the Permittee for a minimum of ten years from the date of the completion of construction. Page 4 of 7 State Stormwater Management Systems Permit No. SW8 071203 13. The Director may notify the permittee when the permitted site does not meet one or more of the minimum requirements of the permit. Within the time frame specified in the notice, the permittee shall submit a written time schedule to the Director for modifying the site to meet minimum requirements. The permittee shall provide copies of revised plans and certification in writing to the Director that the changes have been made. III. GENERAL CONDITIONS This permit is not transferable except after notice to and approval by the Director. In the event of a change of ownership, or a name change, the permittee must submit a formal permit transfer request to the Division of Water Quality, accompanied by a completed name/ownership change form, documentation from the parties involved, and other supporting materials as may be appropriate. The approval of this request will be considered on its merits and may or may not be approved. The permittee is responsible for compliance with all permit conditions until such time as the Division approves the transfer request. 2. Failure to abide by the conditions and limitations contained in this permit may subject the Permittee to enforcement action by the Division of Water Quality, in accordance with North Carolina General Statute 143-215.6A to 143-215.6C. 3. The issuance of this permit does not preclude the Permittee from complying with any and all statutes, rules, regulations, or ordinances, which may be imposed by other government agencies (local, state, and federal) having jurisdiction. 4. In the event that the facilities fail to perform satisfactorily, including the creation of nuisance conditions, the Permittee shall take immediate corrective action, including those as may be required by this Division, such as the construction of additional or replacement stormwater management systems. 5. The permittee grants DENR Staff permission to enter the property during normal business hours for the purpose of inspecting all components of the permitted stormwater management facility. 6. The permit may be modified, revoked and reissued or terminated for cause. The filing of a request for a permit modification, revocation and re -issuance or termination does not stay any permit condition. 7. Unless specified elsewhere, permanent seeding requirements for the stormwater control must follow the guidelines established in the North Carolina Erosion and Sediment Control Planning and Design Manual. 8. Approved plans and specifications for this project are incorporated by reference and are enforceable parts of the permit. 9. The permittee shall notify the Division any name, ownership or mailing address changes within 30 days. Permit issued this the 6th day of December, 2007. NORTH ROLINA ENVIRONMENTAL MANAGEMENT COMMISSION for Coleen H. Sullins, Director Division of Water Quality By Authority of the Environmental Management Commission Page 5 of 7 State Stormwater Management Systems Permit No. SW8 071203 GE — Tooling Repair Center Stormwater Permit No. SW8 071203 New Hanover County Designer's Certification I, , as a duly registered in the State of North Carolina, having been authorized to full time) the construction of the project, (Project) observe (periodically/ weekly/ for (Project Owner) hereby state that, to the best of my abilities, due care and diligence was used in the observation of the project construction such that the construction was observed to be built within substantial compliance and intent of the approved plans and specifications. The checklist of items on page 2 of this form is included in the Certification. Noted deviations from approved plans and specification: Signature Registration Number Date SEAL Page 6 of 7 State Stormwater Management Systems Permit No. SW8 071203 Certification Requirements: 1. The drainage area to the system contains approximately the permitted acreage. 2. The drainage area to the system contains no more than the permitted amount of built -upon area. 3. All the built -upon area associated with the project is graded such that the runoff drains to the system. 4. All roof drains are located such that the runoff is directed into the system. 5. The outlet/bypass structure elevations are per the approved plan. 6. The outlet structure is located per the approved plans. 7. Trash rack is provided on the outlet/bypass structure. 8. All slopes are grassed with permanent vegetation. 9. Vegetated slopes are no steeper than 3:1. 10. The inlets are located per the approved plans and do not cause short- circuiting of the system. 11. The permitted amounts of surface area and/or volume have been provided. 12. Required drawdown devices are correctly sized per the approved plans. 13. All required design depths are provided. 14. All required parts of the system are provided, such as a vegetated shelf, and a forebay. 15. The required system dimensions are provided per the approved plans. cc: NCDENR-DWQ Regional Office New Hanover County Building Inspections Page 7 of 7 DWQ USE ONLY Date Received Fee Paid Permit Number (7-1310 ilq000 Wvo-1 i Zd3 State of North Carolina Department of Environment and Natural Resources Division of Water Quality STORMWATER MANAGEMENT PERMIT APPLICATION FORM This farm may be photocopied for use as an original I. GENERAL INFORMATION 1. Applicants name (specify the name of the corporation, individual, etc. who owns the project): GE Hitachi Nuclear Energy 2. Print Owner/Signing Official's name and title (person legally responsible for facility and compliance): Tood Best - Manager of Facilities & Maintenance 3. Mailing Address for person listed in item 2 above: City:Wilmington State:NC Zip:28401 Phone: (910 1 675-6810 Fax: (910 1 362-6810 Email: tod d.bestQgnf.com 4. Project Name (subdivision, facility, or establishment name - should be consistent with project name on plans, specifications, letters, operation and maintenance agreements, etc.): 5. Location of Project (street address): 3901 Castle Ha)me Road City:Wilmington 6. Directions to project (from nearest major intersection): North two miles on Castle Hayne Road from the intersection of N. Kerr Ave. & Castle Hayne Road 7. Latltude:34 19' 27" Longitude:77 56' 46" W of project 8. Contact person who can answer questions about the project: Name:Mark Hargrove Telephone Number: (910 1 256-9277 Email:mhargrove@withersravenel.com II. PERMIT INFORMATION: 1. Specify whether project is (check one): ®New ❑Renewal []Modification Form SWU-101 Version 8.07 Page I of 2. If this application is being submitted as the result of a renewal or modification to an existing permit, list the existing permit number and its issue date (if known) 3. Specify the type of project (check one): ❑Low Density ®High Density ❑Redevelop ❑General Permit ❑Universal SMP ❑Other 4. Additional Project Requirements (check applicable blanks): ❑CAMA Major ®Sedimentation/Erosion Control 0404/401 Permit ❑NPDES Stormwater 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. Stormwater will be heated by use of a wet detention pond sized to handle 90% TSS removal. 2. Stormwater runoff from this project drains to the Caoe Fear River basin. 3. Total Site Area: 21.2 acres 4. Total Wetlands Area: 9604 acres 5. 100' Wide Strip of Wetland Area: 0 acres (not applicable if no wetlands exist on site) 6. Total Project Area**:21.2 acres 7. Project Built Upon Area:61.7 % 8. How many drainage areas does the project have?1 9. 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 Drainage Area 1 Drainage Area 2 Receiving Stream Name Unamed Crib. to NE Cape Fear River Stream Class & Index No. Class C, SW, 18-74-(52.5) Drainage Area (so 836,327 SF Existing Impervious* Area (so 0 Proposed Impervious*Area (so 568,702 SF % Impervious* Area (total) 68% Impervious* Surface Area Drainage Area 1 Drainage Area 2 On -site Buildings (so 73,500 On -site Streets (so 154,250 On -site Parking (so 96,000 On -site Sidewalks (so 51000 Other on -site (so 239,952 Off -site (so Total (so: 568,702 Impervious area is defined as the built upon area including, but not limited to, buildings, roads, parking areas, sidewalks, gravel areas, etc. **Total project area shall be calculated based on the current policy regarding inclusion of wetlands in the built upon area percentage calculation. Form SWU-101 Version 8.07 Page 2 of 10. How was the off -site impervious area listed above derived? IV. DEED RESTRICTIONS AND PROTECTIVE COVENANTS One of the following 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. Form DRPC-1 High Density Commercial Subdivisions Form DRPC-2 High Density Developments with Outparcels Form DRPC-3 High Density Residential Subdivisions Form DRPC-4 Low Density Commercial Subdivisions Form DRPC-5 Low Density Residential Subdivisions Form DRPC-6 Low Density Residential Subdivisions with Curb Outlets By your signature below, you certify that the recorded deed restrictions and protective covenants for this project shall include all the applicable items required in the above form, 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. V. SUPPLEMENT FORMS The applicable state stormwater management permit supplement form(s) listed below must be submitted for each BMP specified for this project. Contact the Stormwater and General Permits Unit at (919) 733-5083 for the status and availability of these forms. Form SW401-Low Density Low Density Supplement Form SW401-Curb Outlet System Curb Outlet System Supplement Form SW401 -Of f-Site System Off -Site System Supplement Form SW401-Wet Detention Basin Wet Detention Basin Supplement Form SW401-Infiltration Basin Infiltration Basin Supplement Form SW401-Infiltration Trench Underground Infiltration Trench Supplement Form SW401-Bioretention Cell Bioretention Cell Supplement Form SW401-Level Spreader Level Spreader/Filter Strip/Restored Riparian Buffer Supplement Form SW401-Wetland Constructed Wetland Supplement Form SW401-Grassed Swale Grassed Swale Supplement Form SW401-Sand Filter Sand Filter Supplement Form SWU-101 Version 8.07 Page 3 of 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 appropriate DWQ Office. (Appropriate office maybe found by locating project on the interactive online map at http://h2o.enr.state.nc.us/su/msi maos.htm) 1. Please indicate that you have provided the following required information by initialing in the space provided next to each item. Initials • Original and one copy of the Stormwater Management Permit Application Form `-%�, • Original and one copy of the Deed Restrictions & Protective Covenants Form ti 7A • Original of the applicable Supplement Form(s) and O&M agreement(s) for each BMP • Permit application processing fee of $505 ($4,000 for Express) payable to NCDENR • Calculations & detailed narrative description of stormwater treatment/management • Copy of any applicable soil report --'�— • Three copies of plans and specifications (sealed, signed &dated), 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 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) VIL 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):Withers & Ravenel. Inc. Mailing Address:7040 Wrightsville Avenue, Suite 101 City:Wilmington State:NC Zip:28403 Phone: (910 1 256-9277 Fax: (910 ) 256-2584 Email:mhargrove@withersravenel.com VIII. APPLICANT'S CERTIFICATION I, (print or type name of person listed in General Information, item 2) Todd Best certify that the information included on this permit 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 2H .1000. Signature: 4� Date: ��'3o-b% Form SWU-101 Version 8.07 Page 4 of State of North Carolina Department of Environment and Natural Resources Wilmington Regional Office Micltviel F. Easley, Governor FAX COVER SHEET Date: / z//a/D 7 To: Co: Sri/ >Gii pis �A✓�a� L Fax: 2S6 2�5_ Re: GE / 0941'n-J William G. Ross, Jr., Secretary No. Pages (excl. cover): e5 From:J7���/J Phone: Fax: (910)350-2004 A) -iE0'— 127 Cardinal Drive Extension, Wilmington, NC 28405 • (910) 796-7215 . An Equal Opportunity Affirmative Action Employer WITHERS & RAVENEL ENGINEERS I PLANNERS I SURVEYORS 7040 Wrightsville Avenue, Suite io1 WILMINGTON, NORTH CAROLINA, 28403 (910) 256.9277 FAX (910) 256-2584 To: NC Division of Water Quality WE ARE SENDING YOU ❑ Shop Drawings ❑ Copy of Letter LETTER OF T° ° NSWTTAL DATE 012/03/07 JOB NO. 03070722.00 ATTENTION Chris Baker PHONE# RE: GE—ToolingRepair Center High Density Permit ❑ Attached ❑ Under separate covervia ❑ Prints ® Plans ❑ Samples ❑ Change order ❑ Diskette ❑ the following items: ❑ Specifications COPIES DATE NO. DESCRIPTION 2 Sets of plans for stormwater permit 2 Copies of stormwater calculations 2 Stormwater Management Permit Application Form (one original, one copy) 2 Copies of Wet Pond Supplement 1 Application fee for $ 000.00 for express permitting 1 Copy of Wetland Letter from Corps of Engineers 2 Copies of 0&M Agreement (One original & one Copy) THESE ARE TRANSMITTED as checked below: ® For approval ❑ Approved as submitted ❑ Resubmit copies for approval ❑ Foryour use ❑ Approved as noted ❑ Submit copies for distribution ❑ As requested ❑ Returned for corrections ❑ Return corrected prints ❑ For review and comment ❑ ❑ FOR BIDS DUE 20 ❑ PRINTS RETURNED AFTER LOAN TO US REMARKS: For approval. COPYTO: File, Todd Best SIGNED: If enclosures are not as noted, kindly notify us at once. GE - HITACHI NUCLEAR ENGERGY GE - TOOLING REPAIR CENTER STORM WATER CALCULATIONS FOR NCDWQ November 30, 2007 2PQOFEssioa �7 ' a SEAL 19742 -i! 9 FNGINEEP Q0 ''0•,, �/Y. Fi An, Withers & Ravenel, Inc. 7040 Wrightsville Avenue, Suite 101 Wilmington, North Carolina 28403 (910) 256-9277 STORM WATER NARRATIVE GE - HITACHI NUCLEAR ENGERGY GE - TOOLING REPAIR CENTER WILMINGTON, NC December 3, 2007 The address of the site is 3901 Castle Hayne Road, Wilmington, NC. The General Electric site encompasses approximately 1,670 acres. This project involves constructing a + 1.6 acre building along with two large parking lots. The project area for this project totals 21.2 acres The pond designed for this project has been designed for future impervious area that is planned to be built in the future. The wet pond will be designed. to meet New Hanover County's and NCDWQ's stormwater requirements. Calculations are provided for sizing the culverts for 25-year storm and limiting the runoff from the detention pond to pre development flow rates for the 1 yr, 2 yr, 10 yr and 25 yr events. The season high water table at the pond location is 18 inches below the surface. The elevation at the location checked was elevation 29. Thus the seasonal high water table is at elevation 27.50. The proposed normal pool elevation is at elevation 25.00. The pond will be lined with a liner made of existing soils and bentonite that will meet a permeability of 1 x 10-6 cm/sect. The depth of the liner will be confirmed before construction, once all the soils testing has been completed. A 12 inch layer of existing on site material will be placed on top of the liner during construction. The soils on site are On (Onslow Type B), Be (Baymeade Fine Sand, Type A/D), Mu (Murville Fine Sand, Type A), Wr (Wrightsboro Fine Loam, Type C), Ke (Kenansville Fine Sand, Type A.D) and Pn (Pantego Loam, Type B/D. (For soils with the soils group "A/D" or B/D classification, we used "A" or "B". The 1 yr, 24 hr pre and post flow numbers are: Storm Event 1 -Year Pre Development 4.74 Flow Post Development 3.45 Flow Calculations_for determining pre and post flows are provided. WITHERS &i RAVENEL ENGINEERS IPLANNERS ISURVEYORS GE —TOOLING REPAIR CENTER Total Area Draining to Pond= 836,327 SF = 19.20 AC Total Proposed Impervious Surface Area Draining to Pond: Proposed Parking Lots = 96,000 sf Proposed Road = 144,600 sf Proposed Building = 73,500 sf Proposed Sidewalk = 5,000 sf Proposed ABC Stone Security Road = 9,650 sf Future Impervious Area = 239,952 sf 568,702 sf Impervious draining to pond = 568,702/836,327 = 68.0% Required Storage for 1.5-Inch of Runoff For Pond: (use Schueler Method) = 0.05 + 0.009 (1) = 0.05 + 0.009(68) = 0.662 = (1.5")(0.662)(1/12)(836,327) = 69,206 cf (71,109 cf provided @ elevation 26.5) POND DEPTH SA/DA % (FT) 5.00 (avg) 4.86 Avg Depth = 216,445/42,439 = 5.10 — 5.0 ft If Pond Depth =5.0 ft, minimum surface area = 40,645 sf Used 90% TSS chart to size pond Area @ elevation 25.0 = 42,439 SF > 40,645 sf POND SURFACE AREA (MIN.) (SF) 40,645 Kequired storage for forebay: 20% of total permanent pool volume = (0.2)(216,445 co = 43,429 cf (44,598 CF PROVIDED — 20.6%) 107 stokley Drive Wilmington, North Carolina 28403 tel: 910-256-9277 rax:910-256-2584 www.withersravenelxom WITHERS & RAVENEL ENGINEERS I PLANNERS I SURVEYORS Pond Volume Contour IncrementallCumulative Elevation Area Volume Volume ft s c c Bottom Elevation 17.00 14,199 0 0 19.00 2100 1-- 21,116 38,634 - 70,351 23.00 24,994 46,110 v 116,461 _ 24.00 27,037 26,016 142,477 Permanent Pool 25.00 31,703 29,370 171,847 Forebay Volumes Contour Incremental Cumulative _ Elevation Area Volume Volume ft s c c Bottom Elevation 19.00 4,940 0 0 ---- ---------------- ------ ------ --- ---- - 20.00 --- 5,336 5,138 5,138 _ 21.00 6,272 5,804 10,942 22.00 7,280 6,776 17,718 23.00 8,360 7,820 25,538 24.00_ 8,936 34,474_ Permanent Pool 25.00 _9,512 10,736 10,124 44,598 ... _.. _...... ... Foreba Volume is ................. ......... .- of Total Pond Volume 1075tokley Drive Wilmington, North Carolina 28403 tel: 910-256-9277 fax:910-256-2584 www.withersravenelxom WITHERS &— RAVENEL ENGINEERS I PLANNERS I SURVEYORS 1.5" STORAGE VOLUME Contour Incremental Cumulative Elevation Area Volume Volume (ft) (S9 (co (co Normal Pool 25.00 42,439 0 0 25.50 46,739 22,295 22,295 26.00 48,807 23,887 46,181 1.5Storage Level 26.50 50,905 24,928 71,109 POND RELEASE TIME FOR CONTROL PIPE: POND ELEV. EFF. STORAGE VOL. RELEASED OUTFLOW RATE RELEASE TIME _(FTL CF (CF) CFS) HOURS 26.50 71,109 24,928 0.515 13.5 26.00 46,181 23,886 0.420 15.8 25.50 22,295 22,295 0.297 20.8 25.00 0 TOTAL HOURS 50.1 DAYS 2.1 CONTROL PIPE:! 4 INCH ORIFICE HOLE USED ORIFICE EQUATION TO DETERMINE OUTFLOW RATE Q = Cd'A* 22gh "1/2 1075tokley Drive Wilmington, North Carolina 28403 tel: gro-256-9277 fax:gio-256-2584 www.withersravenelxom GE - TOOLING REPAIR CENTER Pond Area Soils Drainage Area Curve No On B 248588 55 13672340 Be A 84404 30 2532120 Wr C 413276 70 28929320 Ke A 24151 30 724530 Pn B 9666 55 531630 Mu A 56228 30 1686840 836313 48076780 19.20 Pre Development Composite CN 57.5 GE - TOOLING REPAIR CENTER Pond Area Impervious CN 98 Pervious CN 57.5 Building Area Drainage Area 836313 Impervious Area 569827 Pervious Area 266486 Post Development Composite CN 85.1 GE - HITACHI NUCLEAR ENGERGY GE - TOOLING REPAIR CENTER PRE AND POST DEVELOPMENT FLOWS Withers & Ravenel, Inc. 7040 Wrightsville Avenue, Suite 101 Wilmington, North Carolina 28403 (910) 256-9277 Hydrograph Report i HydraOow Hydrographs by Intelisolve v9.22 Hyd. No. 1 Pre Development Site Drainage Hydrograph type = SCS Runoff Storm frequency = 1 yrs Time interval = 2 min Drainage area = 19.200 ac Basin Slope = 0.5 % Tc method = KIRPICH Total precip. = 3.70 in Storm duration = 24 hrs Hydrograph Discharge Table Time -- Outflow (min cfs) 740 3.907 742 4.187 744 4.405 746 4.571 748 4.682 750 4.735 << 752 4.729 754 4.669 756 4.556 758 4.396 760 4.194 762 3.956 764 3.692 End Thursday, Nov 29, 2007 Peak discharge = 4.735 cfs Time to peak = 750 min Hyd. volume = 35,787 cuft Curve number = 57.5 Hydraulic length = 2900 ft Time of conc. (Tc) = 27.0 min Distribution = Type III Shape factor = 484 ( Printed VWUel >= 75.00 % d Op.) Hydrograph Report 1 Hydraflow Hydrographs by Intelisolve v9.22 Hyd. No. 1 Post Development Site Drainage Hydrograph type Storm frequency Time interval Drainage area Basin Slope Tc method Total precip. Storm duration = SCS Runoff = 1 yrs = 2 min = 19.200 ac = 0.5 % = KIRPICH = 3.70 in = 24 hrs ' Composite (Area/CN) = [(20.510 x 96) + (11.040 x 56)] / 19.200 Hydrograph Discharge Table Time -- Outflow (hrs cfs) 12.17 22.62 12.20 24.74 12.23 26.67 12.27 28.20 12.30 29.10 12.33 29.36 << 12.37 29.12 12.40 28.56 12.43 27.78 12.47 26.80 12.50 25.62 12.53 24.28 12.57 22.78 .End Thursday, Nov 29, 2007 Peak discharge = 29.36 cfs Time to peak = 12.33 hrs Hyd. volume = 153,328 cuft Curve number = 85.1" Hydraulic length = 2900 ft Time of conc. (Tc) = 27.0 min Distribution = Type III Shape factor = 484 ( Prinleal values- 75 00% of pp.) Hydrograph Report 2 Hydraflow Hydrographs by Inlelisolve v9.22 Thursday, Nov 29, 2007 Hyd. No. 2 Pond Routing Hydrograph type = Reservoir Peak discharge = 3.446 cfs Storm frequency = 1 yrs Time to peak = 14.00 hrs Time interval = 2 min Hyd. volume = 145,437 cuft Inflow hyd. No. = 1 - Post Development Site Drait4gervoir name = Pond Max. Elevation = 26.81 ft Max. Storage = 92,677 cuft Storage Indication method used. Hydrograph Discharge Table Printed values >=75,00%of Qp.) Time Inflow Elevation Clv A Clv B Clv C PfRsr Wr A Wr B Wr C Wr D Exfil Outflow (hrs) cfs ft cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs 13.10 5.850 26.75 5.647 0.528 2.099 ----- ----- ----- ----- ----- ----- 2.627 13.13 5.583 26.75 5.647 0.529 2.185 ----- ----- ----- ----- ----- ----- 2.714 13.17 5.359 26.76 5.647 0.530 2.262 ----- ----- ----- --- ----- ----- 2.792 13.20 5.170 26.76 5.647 0.531 2.331 ----- ----- ----- ----- ----- ----- 2.862 13.23 5.009 26.77 5.647 0.532 2.394 ----- ----- ----- ----- ----- ----- 2.925 13.27 4.870 26.77 5.647 0.532 2.450 ----- ----- ----- ----- ----- ----- 2.982 13.30 4.745 26.78 5.647 0.533 2.501 ----- ----- ---- ----- ----- ----- 3.034 13.33 4.630 26.78 5.647 0.534 2.547 ----- ----- ----- ---- ----- ----- 3.081 13.37 4.525 26.78 5.647 0.534 2.589 ---- ----- ----- ----- ----- ----- 3.123 13.40 4.429 26.79 5.647 0.535 2.626 ----- ----- ----- ----- ----- ----- 3.161 13.43 4.341 26.79 5.647 0.535 2.661 ----- ----- ----- ----- ----- ----- 3.196 13.47 4.261 26.79 5.647 0.536 2.691 ---- ----- ----- ----- ----- ----- 3.227 13.50 4.187 26.79 5.647 0.536 2.719 ----- ----- ----- ---- ----- ----- 3.255 13.53 4.120 26.80 5.647 0.536 2.744 ----- ---- ----- ----- ----- ----- 3.281 13.57 4.057 26.80 5.647 0.537 2.767 ----- ---- ----- ----- ----- ----- 3.303 13.60 4.000 26.80 5,647 0.537 2.787 ----- ----- ----- ----- ----- ----- 3.324 13.63 3.946 26.80 5.647 0.537 2.807 ----- ----- ----- ----- ----- - 3.344 13.67 3.896 26.80 5.647 0.537 2.826 ----- ----- ----- ----- ----- ----- 3.363 13.70 3.848 26.80 5.647 0.537 2.842 ----- ---- ----- ----- ----- ----- 3.380 13.73 3.802 26.80 5.647 0.538 2.857 ----- ----- ----- ----- ----- ----- 3.395 13.77 3.756 26.80 5.647 0.538 2.870 ---- ----- ----- ----- ----- ----- 3.408 13.80 3.711 26.81 5.647 0.538 2.881 ----- ----- ----- ----- ----- ----- 3.418 13.83 3.666 26.81 5.647 0.538 2.889 ----- ----- ----- ----- ----- ----- 3.427 13.87 3.621 26.81 5.647 0.538 2.897 ----- ----- --- ----- ----- 3.435 13.90 3.576 26.81 5.647 0.538 2.902 ----- ----- ----- ---- ----- ----- 3.440 13.93 3.530 26.81 5.647 0.538 2.906 ----- ----- ----- ---- ----- ----- 3.444 13.97 3.485 26.81 5.647 0.538 2.908 ----- ----- ----- ----- ----- ----- 3.446 14.00 3:439 26.81 << 5.647 0.538 2.908 ----- ----- ----- ----- ----- ----- 3.446 << 14.03 3.393 26.81 5.647 0.538 2.907 ----- ----- ----- --- - ----- ----- 3.445 14.07 3.348 26.81 5.647 0.538 2.905 ----- ----- ----- -=-- ----- ----- 3.443 14.10 3.303 26.81 5.647 0.538 2.901 ----- ---- ---- ----- ----- ----- 3.439 14.13 3.259 26.81 5.647 0.538 2.896 ----- ----- ----- ----- ----- ----- 3.434 14.17 3.215 26.81 5.647 0.538 2.889 ----- ----- ----- ----- ----- ----- 3.427 14.20 3.173 26.81 5.647 0.538 2.882 ----- ----- ----- ----- ---- ----- 3.419 14.23 3.133 26.81 5.647 0.538 2.873 ----- ---- ---- ---- ----- ----- 3.411 14.27 3.094 26.80 5.647 0.538 2.863 ---- ----- ----- ----- ----- ----- 3.401 14.30 3.057 26.80 5.647 0.538 2.852 ----- ---- ----- ----- ----- ----- 3.390 14.33 3.022 26.80 5.647 0.537 2.841 ----- ----- ----- ----- ----- ----- 3.378 14.37 2.988 26.80 5.647 0.537 2.828 ---- ----- ----- ----- ----- ----- 3.366 14.40 2.957 26.80 5.647 0.537 2.815 ----- ----- ----- ----- ----- ----- 3.353 Continues on next page... 3 Pond Routing Hydrograph Discharge Table Time Inflow Elevation Clv A Civ B Clv C PfRsr Wr A Wr B Wr C Wr D . Exfil Outflow (hrs) cfs. ft cfs cfs cfs cfs Cfs cfs cfs cfs cfs Cfs 14.43 2.927 26.80 5.647 0.537 2.802 ----- ----- ---- ----- ----- - 3.339 14.47 2.898 26.80 5.647 0.537 2.789 ----- ---- ----- ----- ---- ----- 3.326 14.50 2.871 26.80 5.647 0.537 2.777 ----- ----- ----- ----- ----- ----- 3.314 14.53 2.844 26.80 5.647 0.537 2.764 ----- ----- ----- ---- ----- ----- 3.301 14.57 2.819 26.80 5.647 0.536 2.751 ----- ----- ----- --- ----- 3.288 14.60 2.795 26.80 5.647 0.536 2.738 ----- ----- ----- ----- ----- ----- 3.274 14.63 2.771 26.79 5.647 0.536 2.724 ----- ---- ----- ----- ----- -- 3.260 14.67 2.748 26.79 5.647 0.536 2.710 ----- ----- ----- ----- ---- --- 3.246 14.70 2.726 26.79 5.647 0.536 2.696 ----- ----- ----- - ----- ----- 3.232 14.73 2.703 26.79 5.647 0.535 2.681 ----- ----- ----- --- --- 3.217 14.77 2.681 26.79 5.647 0.535 2.667 ----- ----- ----- ---- ----- ----- 3.202 14.80 2.659 26.79 5.647 0.535 2.652 ----- ----- ---- ----- ----- ----- 3.187 14.83 2.637 26.79 5.647 0.535 2.637 ----- ----- ----- - --- 3.172 14.87 2.615 26.79 5.647 0.535 2.622 ----- ----- ----- ----- ----- --- 3.156 14.90 2,593 26.79 5.647 0.534 2.606 ----- ----- ----- ----- ----- -- 3.141 14.93 2.570 26.78 5.647 0.534 2.591 ----- ----- ----- ----- ----- ----- 3.125 14.97 2.548 26.78 5.647 0.534 2.575 ----- ----- ----- ----- ----- --- 3.109 15.00 2.526 26.78 5.647 0.534 2.559 ----- ----- ----- ----- ----- --- 3.093 15.03 2.504 26.78 5.647 0.534 2.543 ----- ----- ----- ----- ----- ----- 3.076 15.07 2.481 26.78 5.647 0.533 2.527 ----- ----- ----- ----- ----- ----- 3.060 15.10 2.459 26.78 5.647 0.533 2.510 ----- ----- ----- ----- ----- ----- 3.043 15.13 2.436 26.78 5.647 0.533 2.493 ----- ----- ----- ----- ----- --- 3.026 15.17 2.414 26.77 5.647 0.533 2.477 ----- ----- ----- ----- 3.009 15.20 2.392 26.77 5.647 0.533 2.460 ----- ----- ----- ----- ----- ----- 2.992 15.23 2.369 26.77 5.647 0.532 2.443 ----- ----- ----- ----- 2.975 15.27 2.347 26.77 5.647 0.532 2.425 ----- ----- ----- ---- ----- ----- 2.957 15.30 2.324 26.77 5.647 0.532 2.408 ----- ----- ----- ----- ----- ----- 2.940 15.33 2.301 26.77 5.647 0.532 2.391 ----- ----- ----- ----- ----- ----- 2.922 15.37 2.279 26.77 5.647 0.531 2.373 ----- ----- ----- ----- ----- ----- 2.904 15.40 2.256 26.77 5.647 0.531 2.355 ----- ----- ----- --.--- ----- ----- 2.886 15.43 2.233 26.76 5.647 0.531 2.337 ----- ----- ----- ----- ----- ----- 2.868 15.47 2.211 26.76 5.647 0.531 2.319 ----- -=--- ----- ----- ----- ----- 2.850 15.50 2.188 26.76 5.647 0.530 2.301 ----- ----- ----- ----- ----- ----- 2.831 15.53 2.165 26.76 5.647 0.530 2.283 ----- ----- ----- ----- ----- ----- 2.813 15.57 2.143 26.76 5.647 0.530 2.264 ----- ----- ----- ----- ----- ----- 2.794 15.60 2.120 26.76 5.647 0.530 2.246 ----- ----- ----- ----- ----- ----- 2.776 15.63 2.097 26.76 5.647 0.529 2.227 ----- ----- ----- ----- ----- ----- 2.757 15.67 2.074 26.75 5.647 0.529 2.209 ----- ----- ----- ----- ----- ----- 2.738 15.70 2.051 26.75 5.647 0.529 2.190 ----- ----- ----- ----- ----- ----- 2.719 15.73 2.028 26.75 5.647 0.529 2.171 ----- ---- ----- ----- ----- ----- 2.699 15.77 2.006 26.75 5.647 0.528 2.152 ----- ----- ----- ----- ----- ----- 2.680 15.80 1.983 26.75 5.647 0.528 2.133 ----- ---- ----- ----- ----- ----- 2.661 15.83 1.960 26.75 5.647 0.528 2.113 ----- ----- ----- ----- ----- ----- 2.641 15.87 1.937 26.74 5.647 0.528 2.094 ----- ----- ----- ----- ----- ----- 2.622 15.90 1.914 26.74 5.647 0.527 2.075 ----- ----- ----- ----- ----- ----- 2.602 End Pond Report a Hydraflow Hydrographs by Intelisolve v9.22 Thursday, Nov 29, 2007 Pond No. 1 - Pond Pond Data Contours - User -defined contour areas. Average end area method used for volume calculation. Begining Elevation = 25.00 ft Stage I Storage Table Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cult) Total storage (cult) 0.00 25.00 45,092 0 0 0.50 25.50 49,648 23,685 23,685 1.00 26.00 51,818 25,367 49,052 2.00 27.00 56,251 54,035 103,086 3.00 28.00 60,807 58,529 161,615 4.00 29.00 65,488 63,148 224,763 4.20 - 29.20 67,875 13,336 238,099 Culvert / Orifice Structures Weir Structures [A] [B] [C] [PrfRsr] [A] [B] [C] [D] Rise (in) = 36.00 4.00 16.00 0.00 Crest Len (ft) = 25.00 30.00 0.00 0.00 Span (in) = 36.00 4.00 20.00 0.00 Crest El. (ft) = 28.20 28.50 0.00 0.00 No. Barrels = 1 1 3 0 Welr Coeft. = 3.00 3.00 3.33 3.33 Invert El. (ft) = 24.00 25.00 26.50 0.00 Weir Type = Broad Broad -- --- Length (ft) = 92.00 - 0.00 0.00 0.00 Multi -Stage = Yes No No No Slope (%) = 0.30 0.00 0.00 n/a N-Value = .013 .013 .013 n/a Orifice Coen. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 0.000 (by Contour) Multi -Stage = n/a Yes Yes No TW Elev. (ft) = 0.00 Stage (ft) 5.00 4.00 3.00 2.00 1.00 0.00 0.0 10.0 Total Q Note: CulvergOrifice outflows are analyzed under inlet (ic) and outlet (m) control. Weir nears checked for orifice conditions (ic) and submergence (s). Stage / Discharge 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 Elev (ft) 30.00 29.00 28.00 27.00 26.00 25.00 100.0 110.0 120.0 Discharge (cfs) U.S. ARMY CORPS OF ENGINEERS WILMINGTON DISTRICT Action Id. SAW-2007-03568-065 County: New Hanover U.S.G.S. Quad: Castle Havne NOTIFICATION OF JURISDICTIONAL DETERMINATION Property Owner/Agent: General Electric -Hitachi Nuclear Energy Americas. LLC Address: Attn: Mr. Todd Best, Facilities Manager Post Office Box 780 Wilmington, NC 28402 Telephone No.: Properly description Size (acres) appx. 57 Nearest Town Wilmington Nearest Waterway NE Cape Fear River Basin NE Cape Fear USGS HUC 03030007 Coordinates N 34.3243 W 77.9476 Location description The project area is located within the existing GE facilities and property at 3901 Castle Havne Road, to the immediate south and west of the existing structures near the Northeast Cape Fear River- north of Wilmington, NC. Indicate Which of the Following Apply: A. Preliminary Determination Based on preliminary information, there may be wetlands on the above described property. We strongly suggest you have this property inspected to determine the extent of Department of the Army (DA) jurisdiction. To be considered fmal, a jurisdictional determination must be verified by the Corps. This preliminary determination is not an appealable action under the Regulatory Program Administrative Appeal Process ( Reference 33 CFR Part 331). B. Approved Determination _ There are Navigable Waters of the United States within the above described property subject to the permit requirements of Section 10 of the Rivers and Harbors Act and Section 404 of the Clean Water Act. Unless there is a change in the law or our published regulations, this determination may be relied upon for a period not to exceed five years from the date of this notification. _ There are wetlands on the above described property subject to the permit requirements of Section 404 of the Clean Water Act (CWA)(33 USC § 1344). Unless there is a change in the law or our published regulations, this determination may be relied upon for a period not to exceed five years from the date of this notification. _ We strongly suggest you have the wetlands on your property delineated. Due to the size of your property and/or our present workload, the Corps may not be able to accomplish this wetland delineation in a timely manner. For a more timely delineation, you may wish to obtain a consultant. To be considered final, any delineation must be verified by the Corps. _ The wetland on your property have been delineated and the delineation has been verified by the Corps. We strongly suggest you have this delineation surveyed. Upon completion, this survey should be reviewed and verified by the Corps. Once verified, this survey will provide an accurate depiction of all areas subject to CWA jurisdiction on your property which, provided there is no change in the law or our published regulations, may be relied upon for a period not to exceed five years. _ The wetlands have been delineated and surveyed and are accurately depicted on the plat signed by the Corps Regulatory Official identified below on . Unless there is a change in the law or our published regulations, this determination may be relied upon for a period not to exceed five years from the date of this notification. X There are no waters of the U.S., to include wetlands, present on the above described project area which are subject to the permit requirements of Section 404 of the Clean Water Act (33 USC 1344). Unless there is a change in the law or our published regulations, this determination may be relied upon for a period not to exceed five years from the date of this notification. Page 1 of 2 A X The property is located in one of the 20 Coastal Counties subject to regulation under the Coastal Area Management Act (CAMA). You should contact the Division of Coastal Management in Wilmington, NC at (910) 796-7215 to determine their requirements. Placement of dredged or fill material within waters of the US and/or wetlands without a Department of the Army permit may constitute a violation of Section 301 of the Clean Water Act (33 USC § 1311). If you have any questions regarding this determination and/or the Corps regulatory program, please contact Jennifer Frye at 910-251-4923. C. Basis For Determination Please be aware that this prmDerty contains non -jurisdictional isolated wetlands Please contact the North Carolina Division of Water Quality at (919) 733-1786 to discuss the State's regulations and requirements for these waters It was determined that these wetlands are not bordering nei2liborin2 or Conti uous with any Section 404 or Section 10 lurisdiclional waters. This determination is based on information submitted by Withers & Ravenel and a site visit by Jennifer Frye on 10/16/2007. D. Remarks E. Appeals Information (This information applies only to approved jurisdictional determinations as indicated in B. above) This correspondence constitutes an approved jurisdictional determination for the above described site. If you object to this determination, you may request an administrative appeal under Corps regulations at 33 CFR part 331. Enclosed you will find a Notification of Appeal Process (NAP) fact sheet and request for appeal (RFA) form. If you request to appeal this determination you must submit a completed RFA form to the following address: District Engineer, Wilmington Regulatory Division Attri Jennifer Frye, Project Manager, Wilmington Regulatory Field Office Post Office Box 1890 Wilmington, North Carolina 28402-1890 In order for an RFA to be accepted by the Corps, the Corps must determine that it is complete, that it meets the criteria for appeal under 33.CFR part 331.5, and that it has been received by the District Office within 60 days of the date of the NAP. Should you decide to submit an RFA form, it must be received at the above address by 12/31/2007. **It is not necessary to submit an RFA form to the District Office if you do not object to die determination in this correspondence.'• / Corps Regulatory Official:�— Date 10/31/2007 Expiration Date 10/31/2012 Action Id. SAW-2007-03569-065 The Wilmington District is committed to providing the highest level of support to the public. To help us ensure we continue to do so, please complete the attached customer Satisfaction Survey or visit htip:Hwww.saw.usace.army.mil/WETLANDS/index.hlml to complete the survey online. Copy famished: Chad Coburn, DENR-DWQ, Wilmington Regional Office, 127 Cardinal Drive Ext., Wilmington, NC 28405, Troy Beasley, Withers & Ravenel, 7040 Wrightsville Ave., Suite 101, Wilmington, NC 28403 . Page 2 of 2