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HomeMy WebLinkAboutSW8941015_Historical File_19941118 (2)State of North Carolina Department of Environment, Health, and Natural Resources Wilmington Regional Office James B. Hunt, Jr., Governor DIVISION OF ENVIRONMENTAL MANAGEMENT Bob Jamieson Jonathan B. Howes, Secretary WATER QUALITY SECTION Regional Manager November 18, 1994 Mr. Mark B. Pearsall PVC, Incorporated Post Office Box 7246 Rocky Mount, North Carolina 27804 Subject: CERTIFICATION OF COMPLIANCE with Stormwater Regulations Stormwater Project No. SW8 941015 Holiday Inn Wrightsville Beach New Hanover County Dear Mr. Pearsall: This Certification is pursuant to the application for the Holiday Inn Wrightsville Beach received on October 26, 1993, with additional information received November 16, 1994. Staff review of the project plans and specifications has determined that the stormwater control system as proposed will comply with the Stormwater Regulations set forth in Title 15A NCAC 2H.1003(h). Stormwater runoff will be treated by an infiltration basin sized to contain the first inch of runoff from 137,983 square feet of buildings, parking and sidewalks located on the site. Any modification of the plans submitted to and approved by this Office or further- development of this site regardless of the fact that such modification may be less than 1 acre, will require an additional Stormwater Submittal/Modification and approval prior to initiation of construction. Modifications include but are not limited to; project name changes, transfer of ownership, redesign of built -upon surfaces, addition of built -upon surfaces, redesign or further subdivision of the project area as shown on the plans submitted to and approved by this Office. This Certification shall be effective from the date of issuance until rescinded. The project shall be constructed and maintained in accordance with the plans and specifications approved by the Wilmington Regional Office. This Certification does not supersede any other permit or approval. The developer is responsible for obtaining any and all permits and approvals necessary for the development of this project. This could include the Division of Coastal Management under CAMA requirements, The Division of Environmental Management undrPr Wetland 401 Water Quality Certification, and/or a Dredge and Fill Permit, and/or a Sewer Extension/Collection Permit, U.S. Army Corps of Engineers 404 Wetland Permit, NPDES Stormwater Permit if disturbing five acres or more, local County or Town Agency permits under their local ordinances, or others that may be required. 127 Cardinal Drive Extension, Wilmington, N.C. 29405-3945 a Telephone 910-395-3900 O Fax 910-350-2004 An Equal Opportunity Affirmative Action Employer Mr. Pearsall November 18, 1994 Stormwater Project No. SW8 941015 ---------------------------------------------- A professional engineer must certify that the stormwater system has been installed in accordance with the approved plans and specifications upon completion of construction. The attached certification should be received by this Office within 30 days of construction completion. The infiltration structure shall be constructed in it's entirety, permanently vegetated (if applicable), and operational prior to the construction of any impervious surfaces proposed for the project, except roads. If you have any questions concerning this matter, please call Ms. Linda Lewis or me at (910)- 395-3900. Sincerely, Dave Adkins Water Quality Supervisor DA/arl: S:\WQS\STORMWAT\CERTMC\941015.NOV cc: George Cameron Sky, Conklin New Hanover County Building Inspections Beth Easley, New Hanover County John Parker, CAMA Bradley Bennett Linda Lewis Wilmington Regional Office Central files DIVISION OF ENVIRONMENTAL MANAGEm EENT IN LTRATION SYSTEM PROTECT DATA Project Name: Project No.: Location: Applicant Name: Mailing Address: Submittal Date: Water Body Receiving Stormwater Runoff. Classification of Water Body: Basin size: Basin Depth: Bottom Elevation: Design Storage Elevation: Total Impervious Surfaces Allowed: Green Areas Draining to Basin: Storage volume required: Storage volume provided: Infiltration Rate and Type of Soil: Holiday Inn Wrightsville Beach SW8 941015 New Hanover Mr. Mark B. Pearsall PVC, Incorporated Post Office Box 7246 Rocky Mount, North Carolina 27804 October 26, 1993 ICWW "SA" 1107 linear feet of 8'w x 3.5'h trench 3.5' 3.0 MSL 6.55 MSL 137,983 square feet 6,922 square feet 11,128 cubic feet 12,923 cubic feet .52 in/hr, Newhan Sand Comments: Site infiltration rate will be much higher that .52 in/hr. The trench volume provided does not include the side triangles, so the actual capacity is 19,909 cubic feet. Like systems on the island function very well. The trench drains at the entrances to the site act as the overflow weirs. Almost 1.8" of runoff will be handled in the. system prier to any overflow. WMTRATION SYSTEM EVALUATION 1. Yee No System is capable of treating and disposing of runoff from all impervious surfaces resulting from 1-1/2 inches of rain. 2. Yes No The system is located at least 30 feet from surface waters. 3. Yes No The system is a minimum of 100 feet from water supply wells. 4. Yes No The bottom of the system is a minimum of 2 feet above the seasonal high water table. 5. Yes No Runoff in excess of the design volume by-passes the system and does not flush pollutants through the system. 6. Yes No The vegetative filter provides non -erosive flow for the 10 year storm, even distribution of the runoff over the length of the filter, a slope of 5 % or less, and is planted with natural, grassed, or artificially planted wetland vegetation. 7. Yes No The system has been shown to completely draw down in 5 days. 8. Yes No Soil has a minimum hydraulic conductivity of 0.52 in/hr. 9. Yes No The system is not sited on or in fill material. 10. Yes No The system has an observation well. 11. Yes No An Operation and maintenance plan has been provided for the system. 12. Yes No THIS PROJECT MEETS THE STORMWATER CONTROL REQUIRIMENTS OF 15 NCAC 2H. (g), (h), 0), (k) and (1). For YES, items 1-14 must all be highlighted YES. DIVISION OF ENVIRONMENTAL MANAGEMENT SIGN -OFF Wilmington Regional Office 18 LOV 24 ' chi, & Date In idual Evaluating Form/Plans Date Regional Soil Scientist l g R%2�t� c� �iA Date Regional Water Quality Supervisor cc:Applicant/Bradley Bennett/arl/WiRO/CF Holiday Inn Wrightsville Beach New Hanover County Stormwater Project No. SW8 941015 Engineer's Certification L , as a duly registered Professional Engineer in the State of North Carolina, having been authorized to observe (periodically/weekly/full time) the construction of the project, 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. Recorded deed restrictions are attached to provide further evidence that the project has been built within substantial intent of the approved stormwater plans and spectifications. Signature Registration Number Date IMPORTANT ni Date --ALATime ' c 1 WHILE YOU WERE 0 of Phone 64 � AREA CODE NUMBER EXTENSION TELEPHONED PLEASE CALL CALLED TO SEE YOU WILL CALL AGAIN WANTS TO SEE YOU URGENT RETURNED YOUR CALL Message_ HOL I DAY I M J gned N.C. Dept. of Environment, Health, and Natural Resources �v v� Printed on Recycled Paper /1-1¢-qg IMPACT ENGINEERING, P.C. 3805 Wrightsville Avenue, Unit 17 - Wilmington, North Carolina 28403 - 910-350-0631 November 10, 1994 State of North Carolina Department of Environment, Health and Natural Resources 127 Cardinal Drive Extension Wilmington, North Carolina 28405-3845 Attention: Ms. Linda Lewis Subject: Holiday Inn at Wrightsville Beach Stormwater Project No. SW8 941015 New Hanover County Void Ratio of No. 57 Stone Reference: (1) Letter from Ms. Linda Lewis, DEHNR, to Jim Honeycutt, Impact Engineering, dated November 3, 1994 Dear Ms. Lewis, I talked to a Mr. Rich Moses of Martin Marietta Corporation in Wilmington about the void ratio of No. 57 stone. He said I should use 0.40. The stone from Martin Marietta's local Castle Hayne facility has a void ratio of 0.45, so the 0.40 would be conservative. (Jr A -A F`.Pe w [ no col? neGh011 ' 5 { ze,4 t jslaen no .ham It (f l Sincerely, George Cameron 910-256-5915 (home) 910-617-5735 (mobile) oa STATE o State of North Carolina Department of Environment, Health, and Natural Resources Wilmington Regional Office James B. Hunt, Jr., Governor DIVISION OF ENVIRONMENTAL MANAGEMENT Bob Jamieson Jonathan B. Howes, Secretary WATER QUALITY SECTION Regional Manager November 3, 1994 Mr. Jim Honeycutt, P.E. Impact Engineering 3805 Wrightsville Avenue, Unit 17 Wilmington, North Carolina 28403 Subject: ADDITIONAL INFORMATION Stormwater Project No. SW8 941015 Holiday Inn Wrightsville Beach New Hanover County Dear Mr. Honeycutt: The Wilmington Regional Office received a Stormwater Submittal for the Holiday Inn Wrightsville Beach on October 26, 1994. A preliminary review of that information has determined that the submittal for the subject project is not complete. The following information is needed to continue the stormwater review: Label catch basin and trench piping inverts. 2. Where is the connection/overflow control weir structure from the infiltration system into the street piped system? The ability to bypass the excess runoff is required by regulation. Please locate on plans and provide a detail. 3. A signed and notarized Operation and Maintenance Plan for the stormwater controls (currently under development) 4. The assumed void ratio of .4 after compaction must be documented. Please forward a copy of the specification sheet for the chosen #57 stone which indicates the void ratio to be expected after 95 % compaction. 127 Cardinal Drive Extension, Wilmington, N.C. 28405-3845 • Telephone 910-395-3900 0 Fax 910-350-2004 An Equal Opportunity Affirmative Action Employer Mr. Honeycutt November 3, 1994 Stormwater Project No. SW8 941015 Please note that this request for additional information is in response to a preliminary review. The requested information should be received by this Office prior to December 3, 1994, or the submittal will be returned as incomplete. If you have any questions concerning this matter please feel free to call me at (910) 395-3900. Sincerely, Ms. Linda Lewis Environmental Engineer DA/arl: S:1WQSISTORMWATIADDINFO1941015.NOV cc: George Cameron (2) Linda Lewis Central Files 2 Project # 941015 Date 03—Nov-94 Project Name HOLIDAY INN Reviewer ARL Drainage Basin ICWW Classification SC Site Area 179081 Square Feet 4.11 Acres Impervious Area Calculation Buildings Parking/Asphalt Concrete Other Volume/Storage Calculation Required Drainage Area 179081 Square Feet 4.11 Acres 36454 X 1.00 = 36454 square feet 86534 X 0.95 = 82207 square feet 14995 X 0.90 = 13496 square feet 0 X 0.00 = 0 square feet Total 132157 sauare feet Required Volume To Store Pipe Diameter Length Of Pipe Length Of Trench Width Of Trench Height Of Trench Cross —Sectional Area Of Trench Storage In Piping Provided Available Volume To Store (Assuming 40% Voids) Elevation Of Bottom Of Trench (LOWEST) Elevation Of Seasonal High Water Table Exfiltration Rate / Drawdown Miminum Required Exfiltration rate Reported Hydraulic Conductivity (In/Hr) Bottom Surface Area Provided Exfiltration Rate Comments: 11013 Cubic Feet 1.00 Feet 1107.00 Feet 1107.00 Feet 8.00 Feet 3.50 Feet 28.00 Square Feet 3 Cubic Feet 12923 Cubic Feet 3.00 Mean Sea Level 1.00 Mean Sea Level 805.5 Gallon Per Hour 0.52 Inches per Hour 8856.00 Square Feet 2870.5 Gallon Per Hour Per Sauare Foot SJe- is ver Sri o P-ob Qbl� in Pl fr•af2, MLCA �'►,5�e�- g► r-Q+e. TAP)cA vof CCllr. ' e sloes naf Iorskide �i Ac4u0( C12CI' 1•5 C� 0909 Cr / wkl (� ; t 39% Cr wye o4her- y4om5 in '� z �r'eo TUnchon Vefy G)ell. Drainage calculations for Holiday Inn, Wrightsville Beach, NC Project IE-4100 9124/94 A := 179081 e A = 4.111 •sue runoff:- 1•in ...total area of site ...volume of runoff to be stored VsR := runoff•A VsR = 14923 •ft3 ...volume of storage required based on 1" of runoff W :- 8-ft ft ...trench width H := 4-ft ft ...trench depth d := 1-ft ft ...pipe diameter v := 0.4 ...assumed void ratio of stone _ d2 Apipe ' �2 ...cross-sedonal area of pipe L := VsR L = 1124 °Ift ...length of trend required L A pipe + \W -R - A pile . v, Analysis of drawdown time: K := O.52•in K = 1.204.10 ` hr fe time := VsR time = 38.3 •br K•L•W p ECEIV( D OCT 3 1 IM g�oJ 0 swg a4.1015_ Sw '* a SEAL �� 9524 'ZjJ,�'S NQi NVS .� l.tn. - ..." Vz-f-11 Attachment To Evaluation of Stormwater Infilration System Holiday Inn at Wrightsville Beach Item 4: Seasonal High Water Table The seasonal high water table at the Holiday Inn site at Town of Wrightsville Beach can not be readily determined. The seasonal high water table is normally determined by a change in the color of the soil caused as the water table fluctuates leaching the soil. In order for the leaching to occur, the soil must be in place long enough to accumulate leachates and be a suitable size to hold the leachates. The soil at Wrightsville Beach is sand .and has not been in place .long enough to . accumulate leachates. The Holiday Inn is on the site of a Moores Inlet, 'which closed in the 19501s. Per Dr.James Doakal, a professor in the Geology Department at the University of North Carolina at Wilmington, forty years is not long enough for the leachate accumulation. Furthermore, per Vince Lewis, a soil scienctist at the DEHNR, who inspected the sand, the grains are too large to hold the leachates, and, therefore, no discoloration would develop. Sufficient absorbing soil was determined by other means. 1. Two holes were dug on the site - one by North Lumina Ave, which is the lower part of the site (approximately El. 7'-011), and one at end of the site towards the ocean, which is the higher part of: the site (approximately El. 9'-0"). The holes were dug with a posthole digger and were 4'-6" deep. Water was not observed in either hole then or during an inspection three days later. Per the calculations for the drain field and the dimensions of the system, 4'-6" of sand is to absorb the water from the field. 2. Other drain fields close to the site at approximately the same elevation and in the 'same soil conditions were inspected and found to be more than adequate. The Cordgrass condominiums across the street and north two blocks have an infiltration system designed per the Town of Wrightsville Beach and was observed in the rain to be operating satisfactorily. In some cases, the water was being absorbed so well by the sand at the bottom of the catch basins that the water was not rising enough to flow into the horizontal drain field lines. The Town of Wrightsville Beach Inspection Department said the systems installed per the town specification operated well and no problems have been observed. Items 6, 7, 8 & 9: Vegatative Filter A vegetative filter is used to filter infiltration system does not process. for the Holiday Inn is being designed and not have any excess. Therefore, not required. excess water that the The infiltration system to process all the water the vegetative filter is