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HomeMy WebLinkAboutNCG140376_COMPLETE FILE - HISTORICAL_20100128STORMWATER DIVISION CODING SHEET NC6 PERMITS PERMIT N0. DOC TYPE g' HISTORICAL FILE ❑ MONITORING REPORTS DOC DATE ❑ Dou o a YYYYMMDD r-= • Or e ENGINEERING, ENVIRONMENTAL & CONSTRUCTION SERVICES w«Nv.wpceng.co3n January 28, 2010 Ms. Bethany Georgoulias North Carolina Department of Environment and Natural Resources Division of Water Quality 1617 Mail Service Center Raleigh, North Carolina 27699 RE: NPDES Stormwater General Permit NCG140000 Application Blue Ridge Concrete P.O. Box 2594 Weaverville, North Carolina 28787 Dear Ms. Georgoulias: LISTEN • RESPOND • PERFORM On behalf of Blue Ridge Concrete, WPC is providing the following re-submittat and responses to North Carolina Department of Environment and Natural Resources (NCDENR) review comments, dated December 28, 2007. This rc-submittal was submitted and returned in 2008 due to the property not having the appropriate Buncombe County zoning consistency. This issue has been resolved, please see the attached Buncombe County Zoning Consistency letter of December 11, 2009 along with the Buncombe County. With the property now having the correct zoning, the NPDES Permit NCG140000 Application is being resubmitted. This cover letter highlights the requested information based on the past review. Listed below in italics are NCDENR's comments followed by the appropriate response. 1. Plans and Specifications: These must be prepared either by a Professional Engineer or employee internal to the company that is qualified to perform such work in accordance with G.S. 89C-25(7). There were no plans and specifications for the recycle ,system included with the application package, and neither plans nor calculations were signed, sealed, and dated by a RE'. [heir four of the Final Checklist in the application, page 5. ] F E S 10 2010 WATER QUALITY SECTION 2201 ROWLAN3) AVENUE SAVANNAH, GA 31404 TEL 9112.62 4o60%�=FA7c�951' 622'._400.1PICE CHARLESTON • CHARLOTTE • COLUM131A • JACKSONVILLE6,, jV1YRTVF BFACH • SAVANNAH Q �S4 rvi C��Ao ��I!M v�sv�s ,w��� RE: NPDES Stornttvater General Permit NCG 140000 Application Blue Ridge Concrete WPC Project No. WI'C3407.001 b8 January 28, 2010 The plans and specifications have been signed, sealed, and dated by a P.E. and are attached. Specifications are indicated on the drawings as well as in the Stormwater Management flan. 2. Site Map [Item six of the Final Checklist in the application, page 5.] a. The site map does not show an outline of drainage areas, or which drainage areas correspond to which outfall. The drainage sheet (Figure 3) is provided in the Stormwater Management Plan. All drainage at the facility is sheet flow towards the proposed stormwater retention pond. The stormwater retention pond has one discharge outfall. b. The site map does not indicate the location of stormwater discharge oulfalls. The stormwater discharge outfall is shown on the drainage sheet (Figure 3). c. The site map does not specify where materials will he stored (e.g., aggregate piles). The site map (Figure 2) has been revised to show the locations of, all aggregate, and sand stockpiles. d. Will aggregate piles he irrigated? Please clarify on the nzap or in the application, even if no discharge is expected. The stockpiles are not to be irrigated. No discharge is expected. e. The site map sloes not clearly indicate which areas are to he irnpervioits, graveled, etc. Does the magenta outline of' the plant site represent the graveled area, drainage area, or something else? There was no legend to clarify. A legend has been incorporated into the drawings in order to indicate property boundaries, gravel areas, drainage contours, etc. w�-vw wpccrtg.cortt Page 2 of 7 RE: NPDES Stormwater General Permit NCG 140000 Application WPC Project No. WPC3407.001 b8 Blue Ridge Concrete Jamtaiy 28, 2010 WPC., :)dJA www.wpceng.com 3. Recycle System Design Calculations a. There were no details of the recycle system provided. The site map just shows a 50' x 50' "box. " Plans and specifications should be provided that showy the structure in detail, including whether there are multiple settling cells, how the water flows between cells, the proposed berm, whether there is any ramp flowing into the washout system where trucks rinse out, etc. How will the water be reused? In the plant process, for more truck washouts, and/or for other uses? Details of the truck wash out area are provided in Figure 4, Detail Sheet. Section 4.2 of the Stormwater Management Plan presents the process for the truck washout use. As presented in the Stormwater Management flan, the truck washout system is a conical bermed basin 50 .fect in diameter and 10 feet deep. The sides of the truck washout basin will be sloped 4:1. Each concrete truck backs up to the berm and the driver will wash out the truck at the end of each workday with up to 150 gallons. Wash water will be captured by and retained in the truck washout basin. As water accumulates within the basin a floating pump could be used to recycle water during washing operations. Water would then be pumped from the basin- and used to help rinse sediment from the trucks, thereby reducing the total amount of fresh water used during the process. As needed, maintenance will occur to maintain the slope of the basin and surrounding berm. b. The water balance equation provided for the recycle system in not complete. A water balance should show all Inputs -- Outputs = No Accumulation. The Water balance presented In the application package' appears to just calculate design volume. The calculation should demonstrate a balance between (the water dispensed by truck washouts + design .storm volume + freeboard) and (the hater to be used) on a daily basis. If all the water will be used again for the same number of truck washouts, please certify this assumption about what Page 3 of 7 RE: NPDES Stormwater General Permit NCG 140000 Application Blue Ridge Concrete WPC Project No. 1,VI'C3407.00168 January 28, 2010 "operating volume" means. How will the system ensure suffrcienl settling so that the water can be re -used for its purpose? A water balance equation is not applicable to use on the truck washout basin and therefore it is not included in the revised Stormwater Management Plan. c. How will the freeboard be restored after significant rain events? The calculations assert the assumption that "operating volume is retained in the truck washout basin and allowed to percolate into the soil within 2-5 days. " This implies that (1) the entire operating volume will exit the system via percolation into the soil and not by recycling and (2) the soils have an infiltration rate to accommodate this assumption. However, there is no information about the soils to .support this - claim. Furthermore, the calculations go on to assume .sediment from concrete truck washing will be allowed to build up to a depth of 8.5 feet. Haw will a washout basin with 8.5 feet of sediment and concrete residue accumulated at the bottom allow any infiltration into the soil? Please better explain how the freeboard will be restored, in what amount of time it is reasonable, and the basis of ' these assumptions. The capacity of the truck washout basin is 118 000 gallons with one foot of freeboard, which exceeds the combined volume (22;50.O=gallons) .of 1) washing operations, 2) one foot of freeboard required by North Carolina Department of Environment and Natural Resources, and 3) precipitation resulting from a 25-year 24-hour storm, 5.25 inches. The soils on -site are Clifton Soil Series which has an infiltration rate of 0.4 to 0.5 gallons per day per square foot. Even in the case in which the truck washout basin is tilled with 5 feet of washout sediment, 55,000 gallons of water can be contained in the basin while still maintaining 1 foot of freeboard. Calculations for the truck washout system are presented in the Stormwater Management Plan. The truck washout basin, surrounding berm, water level, and the amount of material within the basin will be inspected and monitored daily. As discussed in item "a" above, the wash out basin will fill over time with wash water, rain water in varying amounts, sand, aggregate and minimum amounts of cement. Once the wash out area has filled with five reet of wash out material, the 'YA Ww\N.WE.>ccn`;.corti. Page 4 of 7 RE: NPDES Stormwater General Permit NCG 140000 Application Blue Ridge Concrete J w\VVVNVpCCT1g.CO)11 WPC Project No. WPC340 7,00168 January 28, 2010 material will be excavated and disposed of property. If needed, the water within the washout basin will be pumped from the washout basin into the water storage tank to be used in the concrete batching operations. This will accommodate settling of the truck drum contents, maintain the required free board, as well as allow for potential water use and prevent any wastewater effluent overflow of the washout collection area. d. Will the truck washout recycle system include a pH adjustment system? While overflow may happen rarely in a single rain event if the systeln is designed for the 25 year storm, it is a possibility during the periods of chronic rain events, Even if the absence of pH adjustment is based on the .system maintaining enough freeboard to reasonably accornrriodate consecutive storm events, the calculations imply this system will be earthen, and not concrete. If this is the case, the design should incorporate pH -control to prevent adverse impacts to groundwater. Otherwise, the design and narrative should clearly justify why there is no pH adjustment proposed. Please provide additional information regarding pH adjustment. The facility's standard operating procedure will be t69-n-ariitior-pl-1, by Method 9040C, pII Electrometric Measurement, of the washout collection area on a <weekly=basis.. Based on the measurements, Blue Midge Concrete will manually adjust the pl-I in the basin to maintain the water within the regulated pI-I limit of 6.0 to 9.0. e. Please clarify i(the assumption of the number of trucks per dory is based on an average or maximum design scenario. The assumption of the number of trucks is based on the maximum. 4. Stormwater Retention Basin Design Calculations a. The impervious area fraction in based on 2,344 square feel of impervious surface. It is difficult to discern fr-oin the site plan which areas will be irrrpervious. It is also not clear how much of the site will be paved or graveled, and whether graveled areas are included as impervious cover in the runoff volume calculation using the Simple Method All areas with gravel Page 5 of 7 RE: NPDES Storm ivater General Permit NCG 140000 Application WPC Project No. WPC3407.00168 Blue Ridge Concrete January 28, 2010 WPC :JdJA wwv, wpc;eng.00111 should be considered impervious. Please revise the impervious area and design calculations if necessary. A legend has been inserted into the stormwater drawings. The calculations using the Simple Method have been revised to reflect the correct impervious areas covered with gravel. PIease refer to the attached drawings and the attached runoff volume calculations using the Simple Method. b. If aggregate piles are irrigated at all, any flow from that area (including stormwater that contacts the piles between irrigation) is included wastetivater. If any wastewater flows to the retention basin, that structure must treat the wastewater to meet effluent limits. No information was provided about whether stockpiles will be wetted or how the retention basin will provide, sufficient treatment to meet TSS and pHlimits if applicable. Aggregate piles are not expected to be irrigated. The aggregate bays are positioned with the open,.side--facing=theup-gradient_side' of the property. Stormwater incident on or around the piles will not be capable of carrying particulate from the piles. Therefore, the generation of `wastewater' will not occur to the extent that it would reach the stormwater retention pond. c. Please be aware that Weaverville is a Phase II city, and post -construction stormwater requirements may apply to this project: Buncombe County was recently delegated to administer the post -construction program within its jurisdiction and within some Phase II cities; please consult the County government about retention pond design review requirements. WPC and Blue Ridge Concrete are in continuous contact with the Buncombe County Planning and Development Office. S. Erosion & Sedimentation Control Plan: No documentation verifying that an E&SC Plan has been developed and submitted to the' Division of Land Resources (DLR) or local delegated authority was included with the application. If an E&SC Plan is not required, please explain why not; the site map indicates more than one acre of laird will be disturbed by this project. `Item three of'the Final Checklist in the application, page 5 J. Page 6 of 7 RE: NPDES Stormivater General Permit NCG 140000 Application Blue Ridge Concrete WPCProject No. WPC3407.00168 January 28, 2010 The revised E&SC Plan has been provided as an attachment. WPC will continue to work closely with Blue Ridge Concrete and NCDENR Division of Water Quality in order to maintain compliance with state and local storinwater regulations. Should you have any further questions, please do not hesitate to call us at (912) 629-4000. Respectfully submitted, WPC, Inc. Joseph R. Ross, Jr., MS Staff Environmental Engineer 'XIA WWW wpccng.Coin ���iiti�AR n+rrry SEAL " No.021406 William S. Anderson, lll, �syRaaasa°•g'. Vice President Page 7 of 7 ]Buncombe County {Government Planning and Development .ton E. Creh hton 46 Valley Street, Assistant County Manager/Planning Di cctor Asheville, NC 28801 Telephoite (8j8) 250 4830 Fax (828) 250-6086 Decenlb& 11, 2009 13Iue Ridgc; Concrete Properties, I:I.0 C/o Johnny IMarolley P.O. Box 501 Spruce Pine, NC Ile. Determination of Zoning Consistency Dear wh% Maroncy, This letter is to colltiinl that the property at 50 Nfurphy Hill Road (tax lot PIN 9744-50- 4163) was consistent with the requivenients ol'tllc Buncombe Cowity "Zoning Ordinance, as this property was llnzoned at the tittle application was made. This deternlillA011 is i11aCIC IRII•stRUIL to the ruling ol'the North Carolina Court of Appeals ne«ating.the zoning of this property, effective, April, 2009. Please contact ine if I can be of liniher assistance. Sincerely, �f it in H. Cdnian, AICP, CZO Zoning Administrator Buncombe County Government Planning and Development Jon E. Creighton 46 Valley Street Assistant County Manager/Planning Asheville, NC 28801 Director Telephone (828) 250-4830 Fax (828) 250-6086 LETTER OF PERMIT ISSUANCE October 15, 2009 Mark Turner, President Blue Ridge Concrete Y.O. Box, 2594 Weaverville, NC 28787 Dear Mr. Turner, Please find Stormwater Permit No. S-2008-035 for the Blue Ridge Concrete project enclosed. The permit should be posted on the construction site in a location clearly visible to the public. Several procedures are required by the Stormwater Management Ordinance (Buncombe County Chapter 26 Environment, Article VII Stormwater Management). Please ensure the following items are completed prior to the completion of the project. 1. An operation and maintenance manual for the stormwater management system is created for the end user of the project. A copy must be submitted to this office. If a record plat is required it must reference the Operations and Maintenance Manual which instructs the responsible party about annual maintenance tasks for at least a 20 year period. Following completion of the project the following items are required. 1. The stormwater management plan designer must submit as -built plans, or certify the existing plans as "As -Built" if no changes have occurred, of the installed stormwater improvements. 2. The developer must disclose which party will be responsible for continued maintenance on the record plat and on the stormwater management plan. 3. An Operations and Maintenance Agreement for the stormwater management system must be recorded. See Division 5, Section 5 (f) of the Buncombe County Stormwater Ordinance for more information on the elements of the agreement. 4. The approval of the stormwaterperrnit shall require an enforceable restriction on property usage that runs with the land, such as recorded deed restrictions or protective covenants, to ensure that future development and redevelopment maintains the site consistent with the approved project plans. S. All maintenance documents required by this ordinance must be submitted to the Stormwater Administrator prior to record plat approval. In the case of single family lots not requiring record plats, documentation must be submitted to the Stormwater Administrator before building permits can be issued. Should you have questions or comments feet free to contact this office at (828)250-4848. Sincere�ly 314�, 1/��� v' dot" Mike Goodson, Pi;, CPESC Stormwater Administrator Cc: WPC, Inc. Buncombe County Frosion Control Stormwater Management 250-4848 County of Buncombe STORMWATER MANAGEMENT Telephone: (,425) 2S0-4648 Fax: (828) 250-6086 46 VALLEY STREET ASHEVILLE, NC 28801 LOCATIONS Murphy Dill Road RESPONSIBLE PERSON: Mark Turner Phone: 912/596-1609 Stox mwater Permit No. BLUE RIDGE CONCRETE PROJECT NAME THIS CERTIFIES THAT A STORMWATER PERMIT HAS BEEN ISSUED FOR THE CONSTRUCTION WORK SET OUT ABOVE. STORMWATER ADMINSTRATOR THIS CERTIFICATE MUST BE POSTER AT THE CONSTRUCTION SITE IN A SECURE PLACE FROM THE, TIME WORIe, IS COMMENCED UNTIL STORMWATER ADMINSTRATOR GIVES FINAL APPROVAL. A COPY OF TILE STORMWATER PLAN MUST BE AVAILABLE FOR THE INSPECTORS USE AT ALL TIMES. October 15, 2009