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SW8931114_HISTORICAL FILE_19940309
STORMWATER DIVISION CODING SHEET POST -CONSTRUCTION PERMITS PERMIT NO. SW8 ' 1')my DOC TYPE ❑ CURRENT PERMIT ❑ APPROVED PLANS © HISTORICAL FILE ❑ COMPLIANCE EVALUATION INSPECTION DOC DATE qq-{ p300) YYYYMMDD PARKER & ASSOCIATES, INC. Consulting Engineers - Land Surveyors - Land Planners 306 New Bridge Street - P.O. Box 976 Jacksonville, NC 28541-0976 (919) 455-2414 - Fax: (919) 455-3441 February 25, 1994 Ms. Linda Lewis U ( 91it�i W Environmental Engineer Division of Environmental Management FEB 9 $ 1994 127 Cardinal Drive Extension Wilmington, North Carolina 28405 „............ ..... RE: Stormwater Project No. 931114 Whitewood Village Onslow County, NC Dear Ms. Lewis: This letter is in response to your letter to me dated November 30, 1993 concerning the above referenced project. 1. The street cross-section detail shown on Sheet 8 of 10 is DOT's typical standard street detail. All of the roads in this project are considered "Local Residential" and will have 50 foot right-of-ways and Maplecrest Drive will have 20 foot wide pavement and the Cul-De-Sac roads will have 18 foot wide pavement as shown on the plans. 2. These roads are being designed to meet DOT's standards and are intended to be dedicated to them upon completion of construction. DOT has responded that the roadside ditch slopes should be 3:1, if required by your office. Therefore, we have revised our Street Detail to show 3:1 slopes. See the enclosed copy of a letter from Donnie Huffman dated February 21, 1994. Please find enclosed three copies each of revised sheets 2 and 8 of 10. If you have any additional questions or need any additional information, please call. Enclosures TMS/mpa Very truly yours, PARKER & AS O IA ES, Ti4tJ. Stewart, xc: Mr. Jim Grant (w/enclosures) Mr. Donnie Huffman CF (P) INC. P.E. FEB 2 8 1994 L� D E IN n- n 1114 ENVIRONMENTAL ENGINEERING ■ STORM WATER MANAGEMENT ■ WATER AND WASTEWATER SYSTEMS DEVELOPMENT CONSULTING 0 FEASIBILITY REPORTS ■ ENVIRONMENTAL SCIENCE ■ CONSTRUCTION PLANS STATE OF NORTH CAROLINA DEPARTMENT OF TPANSPORTATION I,NNIES B. HUNT. )R DIVISION OF HIGHWAYS SAM HUNT GOVERNOR 410 New Bridge Street SECRETARY Suite 7A Jacksonville, NC 28540 p� February 21, 1994 KIf ED FEB 2 4 1994 PARKER Division 3 District 1 FILE: V,141'(ewo-0 ATTN: Mr. Tim Stewart, P.E. �� VItL" F Parker and Associates, Inc. P. O. Box 976 Jacksonville, NC 28541-0976 Subject: Slope Requirements for DEHNR Dear Mr. Stewart: I have consulted with Mr. J. H. Medlin, Jr., Assistant Division Engineer, on the above subject. Since both the Department of Environment, Health, and Natural. Resources and the Department of Transportation are both State of North Carolina agencies, tky 51ore_strin9ent__requirements_of_,DEHNR would_overrde our requirements.) Therefore, thy 3:1 slopes should be used. If the 3:1 slopes cannot be obtained within the proposed right-of-way, then additional right-of-way would be required. If I can be of fuither assistance, please advise. Very truly yours, 01,�4 vxz—��— D. R. Huffman District Engineer DRH:as cc: Mr. D. J. Bowers KONWATER Mr. B. B. Dixon - w/attachments u V Illl Mr. J. B. Croom - w/attachments U III, FEB 2 8 1994 U dtm 0T 41 405I 1114- 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 Regional Manager January 14, 1994 Mr. Tim Stewart, P.E. Parker and Associates Post Office Box 976 Jacksonville, North Carolina 28541-0976 Subject: ADDITIONAL INFORMATION Stormwater Project No. 931114 Whitewood Village Onslow County Dear Mr. Stewart: The Wilmington Regional Office received a Stormwater Submittal for the Whitewood Village on November 24, 1993, and requested information on January 11, 1994. A preliminary review of that information has determined that the submittal for the subject project is still not complete. The following information is needed to continue the stormwater review: 1. Item #1 requested on November 30, 1993 has not been added to the plans. The plans you sent me were not revised in any way from the originals received on November 24, 1993. Please add the street names beneath the appropriate part of the section (local residential or residential collector). 2. Please provide three (3) copies of all revised plans. 3. Item #2 requested on November 30, 1993 has not been received. The 2:1 back slope on the road section is unacceptable to this Office. As requested before, a letter from DOT must be provided stating that the 2:1 slope will be maintained or anchored appropriately as necessary. 127 Cardinal Drive Extension, Wilmington, N.C. 29405-3845 • Telephone 910-395-3900 • Fax 910-350-2004 An Equal Opportunity Affirmative Action Employer + Mr. Tim Stewart January 14, 1994 Stormwater Project No. 931114 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 February 14, 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:\WQS\STORMWAT\ADDINFO\931114.JAN cc: (2) Linda Lewis Central Files 2 JAN 1 1 1994 EROSION AND SEDIMENTATION CONTROL NARRATIVE TO SERVE WHITEWOOD VILLAGE OWNER: WIIITEWOOD ENTERPRISES RALEIGH, NORTH CAROLINA November 1993 :V-9 122 SEAL 14575 g ��pr yCl M1tE;:� �Pr M. PARKER AND ASSOCIATES, INC. STO IRTER Engineering - Surveying - Planning P.O. Drawer 976 Jacksonville, North Carolina 28541 919-455-2414 ,UIL�6I56V19�j;, IIJnU� JAN 1 1 1994 U :# 931 h oTlq ®ap,Mpitt c 1993 by Parker & Associates, Inc. All rights reserved. No part of this document may be reproduced in any form or by any means without prior written permission. Use of this document, except by those expressly authorized, is strictly prohibited. INDEX 1. Title Page .......................... :...................... 1 2. Index ...................................................... 1 3. Project Information Sheet .................................. 1 4. Sedimentation Control Narrative ......................... NR-1 - 7 5. Engineering Assumptions and Tables ...................... EA-1 - 2 6. Engineering Calculations ................................ EC-1 - 2 Appendix I, Financial Responsibility Form (copy) Appendix II, Density Limits for Stormwater Control (copy) PROJECT INFORMATION SHEET '- OWNER: Whitewood Enterprises 4408 Leota Drive Raleigh, North Carolina 27603-3828 Contact Person: Mr. James B. Grant (404) 378-6055 ENGINEER: Parker and Associates, Inc. P. O. Box 976 Jacksonville, North Carolina 28541-0976 Contact Person: Timothy M. Stewart, P.E. John W. Parker, R.L.S. (919) 455-2414 SEDIMENTATION CONTROL NARRATIVE 1. PURPOSE: The purpose of this report is to provide specifications for the measures and methods proposed to control accelerated erosion and sedimentation resulting from the land disturbing activities of more than one contiguous acre in size. This report is prepared for conformance with the requirements of the Sedimentation Pollution Control Act of 1973. Other regulatory program requirements are carefully considered in the site design, but this report does not assure nor imply conformance with any other rules, laws, or regulatory standards. 2. SCOPE OF WORK: This report will include a general description of existing conditions, proposed use of the site, proposed changes to the site to accomplish the proposed use, and the proposed measures to be taken for the control of accelerated erosion and sedimentation during land disturbing activities. The use of this report will require a review and familiarization with the plans and appendices, as they will clarify and supplement the narrative information. The services provided by this report are intended solely for the benefit of the Financially Responsible Person. Nothing contained herein shall confer any rights upon or create any duties on the part of the design firm toward any person other than the Financially Responsible Person. The Contractor(s) conducting the land disturbing activity, as delegated by the Financially Responsible Person, is solely responsible for the detailed means, methods, procedures, sequencing, co-ordination, job safety, and failures to carry out that work in conformance with this report, specifications, and plans. Observations and inspections by,the design firm does not assume nor imply any assumption of any supervisory responsibilities by the design firm. This report shall constitute supplementary conditions for the work specified herein and if any other provisions are found to conflict with these provisions, the most restrictive provision shall apply. This report, and any specifications and plans which this report is part of or contingent to, shall be on site at all times that any of the specified work is being actively prosecuted on the site. The Sedimentation Pollution Control Act of 1973 and resulting sedimentation control programs are performance oriented. Storm water runoff events exceeding mandatory design guidelines can and do occur. The Contractor shall actively prosecute the goal of minimizing off - site sedimentation by the installation, maintenance, and amendment of measures in conformance with this report with the intent of precluding off -site accelerated sedimentation. NR-2 3. PROJECT DESCRIPTION: Whitewood Village is a proposed 54 lot subdivision located on NCSR 1518, in Onslow County, North Carolina. This section contains approximately 23.5 acres, of which 4.4 acres will be disturbed during construction of the roads, ditches, and swales, and water and sewer installation. 4. EXISTING CONDITIONS The site is currently wooded. Based on the Onslow County Soil Maps, this site consists mostly of Torhunta fine sandy -loam in the front of the project (along NCSR 1518) and Foreston loamy fine sand soils in the back. Torhunta soils are typically very poorly drained, with 0.5 to 1.5 Seasonal High Water Table, and are moderately favorable for drainage. Foreston soils are typically moderately well drained, with 2.0 - 3.5 feet to Seasonal High Water Table, and are favorable for drainage. Both types of soils contain a high amount of fine material which need to be filtered from the runoff prior to discharge. The soil also has poor resistance to erosion of ditch banks and slopes. 5. SEDIMENT CONTROL STRUCTURES AND MEASURES: The following structures, facilities, and measures are proposed for control of accelerated erosion and sedimentation. All of the specified facilities and measures may not be used on any one site or portion of a site but are provided in case of changes in work scope, unpredictable changes in site character, or ineffectiveness of the planned measures. The specifications provided for the facilities and measures should assist in determining which measures are most appropriate when additional measures are considered desirable. A. Construction Sequence: Sequencing a timely execution of construction activities is considered the most effective means for controlling accelerated erosion and sedimentation. Controlling the source of sedimenta- tion is a more efficient and cost effective approach to provid- ing for control of off -site accelerated sedimentation resulting from construction activities. The following construction sequence(s) will define the relative timeliness of installing sediment control measures and the timely stabilization of the contributing watersheds. No work shall be prosecuted until the relevant permits and approvals are obtained. Relevant permits and approvals shall include but may not be limited to: (a) water and sewer system extension approval by the N. C. Division of Environmental Health (DEH) and N.C. Division of Environmental Management (DEM), respectively; (b) storm water control approval by DEM; and (c) sediment control plan approval by the N.C. Land Quality Sec- tion (LQS) and roads and drainage approval by N.C. Department of Transportation. Prior to any land disturbing activities, a pre - construction conference should be established at a place and time acceptable to LQS personnel. NR-3 Sediment Control Construction Operation Sequence: 1. Place stabilized construction entrances at the entrances to the subdivision on Maplecrest Way from NCSR 1518. 2. Rough grade street profiles. Install sediment traps and rock check dams in the permanent road side ditches. 3. Enlarge, amend, and maintain sedimentation control measur- ers as needed for revised watershed conditions and effec- tive restraint of off -site sedimentation. 4. Install all subsurface utilities, including water, sewer, storm drainage, electrical, etc., which will be located within the street rights -of -way. Reshape any roads and ditch work that is disturbed. Place CABC, then asphalt, on roads. Install rip rap scour pads at all pipe outlets. 5. Seed and mulch or otherwise stabilize all road shoulders and ditches and all disturbed areas within 30 working days of completing any phase of construction. 6. Seed and mulch or otherwise provide protective cover sufficient to restrain accelerated erosion upon completion of construction or cessation of work, within 30 working days or 120 calendar days, whichever is less. 7. All sedimentation control devices and facilities not displaced by watershed stabilization shall be maintained at the full functional capacity until the contributing watershed is stabilized. Sediment traps shall be main- tained to at least 50% of the original installation volume until the contributing watershed is stabilized. 8. Upon final stabilization, clean out and/or fill sediment traps and remove rock check dams and inspect and maintain all rip rap scour pads. The approximate construction duration is expected to be between 4 to 6 months. Work is expected to begin imme- diately upon plan approval by LQS. S. Stabilized Construction Entrance: This facility shall be constructed as shown on the detail. It shall be placed at all locations of construction access to the project from public right-of-ways or adjacent properties. If the gravel pad is found to be ineffective, other measures such as enlarging the entrance or washing all construction vehicle tires may be required to prevent sediment tracking onto public rights -of -way or other paved areas serviced by storm drainage collection systems. As permanent stabilization is established and progresses to the interior of the project, the construction entrance or similar means shall be progressively located to remain at the interface of the construction activities in NR-4 progress an the project areas that are stabilized. This detail may also be used to stabilize contractor staging areas inside the project boundaries. C. Silt Fences: Fabric silt fences shall be constructed as per the detail. These devices may be sued at storm drain inlets not subject to concentrated storm run-off and any other areas designated that typically do not receive diffused surface water flow in quanti- ties greater than one cubic foot per second per ten foot sections of the proposed silt fence. Silt fences shall be inspected after every rain and at intervals not exceeding one week. Accumulated sediment shall be removed and placed in approved spoils areas. Any deterioration of this device shall require immediate repair to a state of 100% functional stabili- ty. D. Finish Grades: All cut and fill grading shall be maintained to provide positive surface drainage throughout the construction process in the areas of the construction activities. All outlets constructed for this purpose shall be provided with sediment control devices. All cut and.fill areas shall be shaped to final grade in one continuous operation. Cut and fill slopes which shall be stabilized with vegetation requiring mowing maintenance, shall be no steeper than 3:1 (horizontal:vertical). No cut or fill slopes in or immediately parallel to rights -of -ways or easements shall exceed 2:1. The side slopes of excavated trenches in cohesionless soil materials shall not exceed 2:1. All cut or fill slopes subject to concentrated storm water run-on shall be provided with diversions or slope drains to protect the slope face. E. Permanent Velocity Control Measures (Rip Rap Scour Pad): All storm drain outlets that exceed allowable velocities shall be provided with velocity transition facilities to minimize outlet scour. outlet velocities are determined in the manner stated in the Engineering Assumptions. The average velocities for permanent swales or channels shown on the plans are designed to be less than the control velocity of the soil materials expected in those channels, or are provided with an erosion resistant liner. Additional engineering assumptions are specified on .each applicable detail. Specific measures for this purpose may include but shall not be limited to channel linings, rip rap aprons, check dams, dissipator basins, slope drains, and permanent ,diversion swales. Rock check dams or treated wood check dams may be installed as permanent facilities to reduce average ditch and swale energy gradients. These facilities shall be installed in conformance with the applicable details. RUM F. Temporary Velocity Control Measures (Rock Check Dams and Sediment Traps): Typical temporary velocity control devices may include but shall not be limited to check dams, temporary diversions, debris bar- riers, staked straw bales and sediment traps. Measures shall be constructed as per the applicable detail(s). Standard rock check dams may be used in permanent channels where the expected :design velocities are less that 3.5 fps. Fortified rock check dams are used for velocities exceeding 3.5 fps and the stone is sized for the design velocities based on the charts in the Engineering Assumptions. Energy checks will be used in all temporary and permanent channels where the channel degradation for bare soil conditions is expected or becomes self-evident during the site development. Use of staked straw bales shall include only those situations where a filtering function is not required. Typical uses may include placement in sediment basin interiors to increase travel path tortuosity, increase sediment trap efficiency, and as temporary diversions in locations initially inaccessible by construction equipment. Sediment traps are sized and located in the manner stated in the Engi- neering Assumptions. G. Protective Ground Cover: Areas to be protected by permanent vegetative cover shall include but shall not be limited to any soil area denuded of a protective cover during the construction and not otherwise stabilized by improvements during the development construction process. Any undirected disturbed areas shall be stabilized at the expense of the Contractor. In cases using grass for permanent stabilization, the work shall include but not be limited to appropriate tilling of the area, the application of soil amendments, sowing of seed, and placing of appropriate mulch. Areas to be stabilized by landscape plantings and turf shall be installed in conformance with the landscaping and turf specifications. Areas to be seeded for grass stabilization shall be given an initial application of agricultural lime at a rate of at least 4,000 pounds per acre, superphosphate at 600 pounds per acre, and 12-4-8 grade fertilizer (or equivalent) at a rate of 600 pounds per acre, all of which shall be thoroughly mixed with the soil. After the area to be seeded is brought to proper finish grade, the entire area shall be tilled on the contour to a minimum depth of 4-inches by discing, harrowing, or other approved means. Following tillage, all large debris and stones shall be removed and the surface leveled to a smooth aspect. Dense or compacted soil areas and cut grade soil areas shall be ripped at greater than 6-inches of depth with a spring toothed ripper or similar equipment after finish grade but before tillage. Severely compacted surfaces shall be ripped to at least 12-inches of depth. No compacted soils subject to grassing for stabilization shall be covered with soil fill until ripped. Finish grades on slopes exceeding 30% shall be rough- NR-6 ened parallel to contours to maximize surface storage and minimize run-off. Upon completion of ground and soil preparation work, a grass seed mixture of 100 pounds per acre of "Rebel" fescue, 25 pounds per acre of common bermuda grass, and 10 pounds per acre of centipede grass shall be sown. Bermuda grass seed shall be in an unhulled (with hulls) condition from September 1 to April 1 and be in a hulled (without hulls) condition at all other times. Substitutions for "Rebel" fescue will be consid- ered acceptable if the substituted tall fescue variety has no ratings less than 115" as determined by the USDA 1983 Tall Fescue Trials or more recent USDA trial data. This shall be followed by placing a suitable cover of clean grain straw or approved equivalent mulch at a rate of 1 1/2 to 2 tons per seeded area. In the case of sloping areas or other areas of more concentrated storm water run-off, the straw shall be stabilized by the application of an asphalt emulsion or other approved binding materials. Alternative methods such as hydro -seeding and hydro - mulching will be considered on an individual basis. The Contractor shall guarantee a full stand of grass over the entire seeded area. A full stand of grass will be considered acceptable when areal cover is at least 95% at a uniform minimum height of 3 inches. The Contractor shall then top -dress the stand of grass with a minimum of 300 pounds per acre of 12-4-8 fertilizer (or equivalent). Annual weed grasses and grain weeds shall not be considered part of the minimum areal cover, and seedling stands shall not be considered acceptable until the stand of specified species reaches a state of uniform post - seedling maturity. If straw mulching results in competing stands of grain, maintenance shall include mowing of the grain weed stand to a height of three (3) inches prior to reaching a height of seven (7) inches. Unacceptable grass stands shall be overseeded, after aeration by spiker, at half the original rate, as many times as necessary to establish an acceptable stand. Temporary protective cover may include solid plastic sheeting, porous mats, coarse aggregate, spraying of soil stabilizer concentrates, temporary grass cover, heavy applications of straw mulch, and other measures that protect bare soil surfaces from accelerated erosion. Commercial products shall be utilized in conformance with the manufacturers recommendations. Clean grain straw shall be applied uniformly at a minimum rate of five (5) tons per acre. Methods and measures utilized will be considered acceptable only within the specific context of the use for each individual circumstance and the effectiveness in controlling accelerated erosion. NR-7 H. Maintenance• All erosion and sedimentation control devices and measures shall remain in place and be maintained to full functional capacity by the Contractor until the measure is displaced by permanent development features or all of the contributing watershed is stabilized to the point of no longer contributing accelerated sedimentation. All devices shall be inspected on at least a weekly basis, and maintained at 100% functional design capacity. All sediment traps and other sediment storage structures shall be maintained to at least 500 of their sediment storage capacity until watershed stabilization or removal. M ENGINEERING ASSUMPTIONS A. Storm Water Discharge Outlet Protection: Outlet protection is provided where the average velocity of the ten year storm exceeds the maximum allowable velocity of the receiving soil conditions specified by the Sedimentation Control Act of 1973. The estimated storm water exit velocities and control velocities are given in the drainage data chart or applicable details. Control velocities specified by law are given in Table A. Control velocities applicable to the specific site conditions are estimated by using Table B and the UNIFIED soil classification of the site soil conditions. Outlet velocities for a given discharge were determined using Manning's Formula and Hydraulic Engineering Circular #5 (U.S. Bureau of Public Roads, 1965). For culverts that were designed for discharge rates greater than the ten year return interval storm and similar circumstances, less than full flow conditions were estimated using Table C. Charts and formulas on Table D or Rip Rap apron details were used to estimate the median diameter of stone rip rap used as velocity control measures. MANNING'S FORMULA Q = (1.486/n)(A)(R%)(SI/O V = Q/A B. Storm Water Run-off Rates: The design peak discharge rates are shown on the drainage data chart or applicable details. Erosion and sedimentation control measures and devices are designed to be stable during the ten year return interval storm. If other return interval peak discharges are used, they are clearly identified on the applicable detail. The methods used to estimate peak discharge rates are referenced on the drainage data charts or applicable details. C. Stable Channel Designs: The criteria specified on pages 8.05.1 through 8.05.26 of the "North Carolina Erosion and Sediment Control Planning and Design Manual" are used as design guidelines in addition to the tables specified in Section A of this part (Storm Water Discharge Outlet Protection). Temporary channel linings are designed for channels that exceed permissible velocities specified in Table A. Permanent channel linings are designed where velocities exceed permissible velocities specified in Table E. Temporary linings may be designed for the two or ten year return interval peak discharge. Permanent liners are designed for the ten year return interval peak discharge. Shear stress is evaluated for all flexible liners with total Td values not to exceed those specified on Table F. Computed stress values are specified on the applicable details. EA-2 D. Sediment Traps: Typical sediment trap volumes are based on � acre inch of sediment storage per year per acre of contributing watershed. Typical sediment traps do not exceed five acres of contributing watershed and are sized for an exposure duration of six months. A minimum of 33.5 cubic yards/acre sediment storage is provided with multiple containment distributed throughout the conveyance system at locations considered most critical or most efficient in sediment entrapment. Sediment traps with volumes unspecified on the plans are in addition to the design volumes for typical sediment traps and shall contain a minimum of three cubic yards of sediment storage. This type of sediment trap is for the purpose of minimizing heavy sediment trap clogging of closed storm water conduits and shall include but not be limited to culvert inlet pits, catch basin sediment traps, junction box sediment traps, and culvert outlet pits. Where volumes are specified, they are not in addition to typical sediment trap design unless an exposure duration exceeding six months is specified. Where exposure durations are expected to exceed six months, a 12 month duration is assumed and a minimum of 67 cubic yards of storage volume is provided per disturbed acre. where prevalent disturbed soil conditions are expected to be clays, silts, and loams, a minimum of 70% trapping efficiency is assumed. Where prevalent disturbed soil conditions are expected to be sands and sandy loams, a minimum of 90% trapping efficiency is assumed. The exposure duration, prevalent soil condi- tions, and size of contributing watershed is specified on the plans for each sediment trap of exposure durations exceeding 12 months. TYPICAL DITCH AND SWALE ENGINEERING CALCULATIONS - WHITEWOOD VILLAGE Section Area OM Manninos N % Velocity Depth Top See Plans Acres CFS Bare Stabilized Grade_ Bare Stabilized of of for Location (Ft./Sec) (Ft./Sec) Flow Bank A -A 1.30 3.7 0.025 0.07 0.4 1.6 0.7 0.9 Stab. 2.2' +/- (Roadside Ditch) 12" Grass 0.6 Bare (Typ.) 3:1 Road Slope 2:1 Back Slope B-B 1.91 5.5 0.025 0.05 0.4 1.5 0.9 0.6 Stab. 2.0' +/- (Swale) 2" Mowed 0.5 Bare (Typ.) Grass 5:1 Side Slopes C-C 10.46 38.0 0.025 0.035 0.30 3.3 2.6 2.3 Stab. 4' +/- (Channel) Weeds 2.0 Bare 3:1 Side Slopes 1.5' Bottom NOTES: 1) These sections are typical of other channels, swales, 2) See Detail Sheet, for Construction Section Detail. 3) Calculations using Flowmaster I Version 3.3 Program, roadside ditches in the project. Utilizing Mannings Equation. COJ\WHITEWOOD.CL2 WHITEWOOD VILLAGE ENGINEERING CALCULATIONS SEDIMENT TRAP SIZING Sediment Trap Number Disturbed Area Volume ST #1 0.34 Ac. 11.3 C.Y. ST #2 0.17 Ac. 5.7 C.Y. ST #3 0.25 Ac. 8.3 C.Y. ST #4 0.25 Ac. 8.3 C.Y. ST #5 0.35 Ac. 11.7 C.Y. ST #6 0.63 Ac. 21.0 C.Y. ST #7 0.29 Ac. 9.7 C.Y. ST #8 0.06 Ac. 2.0 C.Y. ST #9 0.41 Ac. 13.7 C.Y. ST #10 0.14 Ac. 4.7 C.Y. ST #11 0.14 Ac. 4.7 C.Y. ST #12 0.37 Ac. 12.3 C.Y. ST #13 0.24 Ac. 8.0 C.Y. ST #14 0.19 Ac. 6.3 C.Y. ST #15 0.09 Ac. 3.0 C.Y. Design Standard - 66.7 C.Y. per acre per year - Assume maximum 6-month period from start of construction to final stabilization yields 33.3 C.Y. per acre per year FINANCIAL RESPONSIBILITY/OWNERSHIP FORM . SEDIMENTATION POLLUTION CONTROL. ACTT No person may initiate any land -disturbing activity on one or more contiguous acres as covered by the Act before this form and an acceptable erosion and sedimentation control plan have been completed and approved by the Land Quality Section, N.C. Department of Environment, Health, and Natural Resources. (Please type or print and, if question is not applicable, place N/A in the blank.) Part A. 1. Project Name— Whitewood Village__ 2. Location of land -disturbing activity: County or Township_ Stump Hound and Highway / StreetNCSR 1518 3. Approximate date !and -disturbing activity will be commenced: January, 1994 3. Purpose of development (residential, commercial, industrial, etc.) :_ Residential 5. Total acreage disturbed or uncovered (including off -site borrow and waste areas ) 6. Amount of fee enclosed $ 110.00 7. Has an erosion and sedimentation control plan been filed ? Yes x No S. Person to contact should sediment control issues arise during land. dislurbirig activity. James B. Grant, P.E. 4.4 Acres Telephone (404) 378-6055 9. Landowner (s) of Record (Use blank page to list additional owners.): Testamentary Tigers, Inc. City Name (s) — ---- ---- — -- 4408 Leota Drive Current Mailing Address Current Street Address Raleigh, North Carolina 27603 _ City Stale Zip City State Zip — 10. Recorded in Deed Book No. _ 1071 Page No. 107 Part B. - — i. Person (s) or firms (s) who are financially responsible for this land -disturbing activity (Use the blank page to list additional persons or,firms): Whitewood Enterprises Name of Person (s)or Firm (s) ---- --- 4408 Leota DRive -- --- — hlai!in.g Address Street Address Raleigh, North Carolina 27603 City — State — -- Zip City -----State Zip Telephone— (404) 378-6055 Teie n� o 2. (a) If the Financially Responsible Party is not a resident of North Carolina give name and street address of a North Carolina Agent. N/A Name Mailing Address Street Address City State Zip City State Zip Telephone Telephone (b) If the Financially Responsible Party is a Partnership or other person engaging in business under an assumed name, attach a copy of the certificate of assumed name. If the Financially Responsible Party is a Corporation give name and street address of the Registered Agent. N/A Name of Registered Agent Mailing Address Street Address City State Zip City State Zip Telephone Telephone The above information is true and correct to the best of my knowledge and belief and was provided by me under oath. ( This form must be signed by the financially responsible person if an individual or his attorney -in - fact or if not an individual by an officer, director, partner, or registered agent with authority to execute instru- ments for the finanacially responsible person ). I agree to provide corrected information should there be any change in the information provided herein. James B. Grant, P.E. Owner Type or prin name Title or Authority Signature n . Date � I, Tp -Kcc I G h(� A ( _, a Notary Public of the County of Ft-1'Lt�f 4 ,@ , State of NeA#!$erv♦`m hereby certify that — appeared personally before me this day and being duly sworn acknowledged that the above form was exe- cuted by him. Witness my hand and notarial seal, this _LO day of O`I• 1g j a2k rvQ . Notary kltwy PuE0% DcYJ.ab 0x%M CsaT!a Mycommissionexpires A",'T DIVISION OF ENVIRONMENTAL MANAGEMENT DENSITY X ENGINEERED PROJECT DATA Project Name Whitewood Village Location (County, Township/Municipality, Address, State Road) ons low Count Owner's Name Whitewood Enterprises MailingAddress 4408 Leota Drive; Raleigh, North Carolina 27603-3828 Phone Number (404) 378-6055 Submittal Date November 19, 1993 Brief Description (include map and appropriate drawings) 54 Lot Subdivision with strip pavement roads and roadside ditches Name of Water Body Receiving Stormwater Runoff Mi 11 Creek Classification of Water Body SA -If SA waters, engineered system, and distance is <0.5 miles, attach report of chloride sampling results N/A mg/I State/Federal Permits/Approvals Required (Check appropriate blanks) CAMA Major 404 Permit X Other (Specify) CALCULATION OF BUILT UPON AREA Sedimentation/Erosion Control DEM/DHS Sewage Disposal_ W X Built upon area means that portion of a development that is covered by impervious or partially pervious cover including buildings, pavement, recreation facilities, gravel, etc., but not including wood decking. If the project includes areas draining to different water classifications, please note them separately below. Subwatershed Subwatershed Classification SA Built upon area 5.88 Max Total Project Area 23.53 Acres % Built upon Area 25% Max_ Allowable B/U Area 25% Max. Is the Project B/U Area 5 the Allowable B/U Area? Yes (If no, an engineered system is required.) % Built upon area = (built upon area / total project area) * 100 Built upon area limits for projects to meet density: SA waters X- 25%, Other STORMWATER COLLECTION SYSTEM Describe how the runoff will be treated Grass -lined Swales & Ditches Office use only Is the built upon area at least 30 feet from mean high water of all surface waters'? Yes _ If no, please provide a description (Note: Only boat ramps, public roads, public bridges, and walkways to water re!ated facilities are allowed within 30 feet of the mean high water line if the project is intended to meet stormwater control requirements through density limits.) DEED RESTRICTIONS AND PROTECTIVE COVENANTS By my signature below, I certify that the recorded deed restrictions and protective covenants for this project shall limit the allowable built -upon area per lot to 3533 square feet inclusive of right-of-way, structures, pavement, walkways or patios of brick, stone, or slate, not including wood decking, state that the covenants will be binding on all parties and persons claiming under them, that they will rum with the land, and that benefits may be enforced by the State of North Carolina, therefore, the covenant cannot be changed or deleted without consent of the State. CERTIFICATION I, James B. Grant, P.E. , certify that the information included on this submittal form is correct, that the project will be constructed in conformance with this information, and that to the best of my knowledge, the proposed project complies with the requirements of 15 NCAC 2H.1003 (b). I authorize the below named person or firm to submit stormwater plans on my behalf, and agree to abide by the deed restriction statement above. O is Signature Date f L Provide authorized person or firm name and address below: Parker & Associates, Inc. P. 0. Box 976 Jacksonville, North Carolina 28541-0976 I, i ( T��OnL 5"qll allotaryPublicfortheStateof Aq County of do hereby certify that personally appeared before me this CD day of L410li. 19 ,J ,and acknowledges the due execution of the foregoing instrument. Witness my hand and official sea], G CiC(� 0. JhEy lWvo Notary Fi'b',10. DOM0) County, C=gW hly cgmmission expires MY 17X DIVISION OF ENVIRONMENTAL MANAGEMENT SIGN -OFF Regional Office Date Date Individual Evaluating Forms/Plans Regional Water Quality Supervisor cc: Applicant/V,'iR0/Bradley Bennett/Central Files 0 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 Regional Manager November 30, 1993 Mr. Tim Stewart, P.E. Parker and Associates Post Office Box 976 Jacksonville, North Carolina 28541-0976 Subject: ADDITIONAL INFORMATION Stormwater Project No. 931114 Whitewood Village Onslow County Dear Mr. Stewart: The Wilmington Regional Office received a Stormwater Submittal for the Whitewood Village on November 24, 1993. 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: 1. Please list the street names beneath the corresponding section. I cannot tell what is a local residential and what is a residential collector. All pavement is noted as 18' wide, anyway. Why are there 2 sections if only one is applicable for this project? 2. As with the Horse Creek Farms project, the ditch slopes must be 3:1 unless a letter from the owner stating that if 2:1 is not sufficient to prevent erosion prior to the road being accepted by DOT, then the slope will either be cut back to 3:1 or permanently anchored. DOT must also supply a letter that if, after accepting the roads, erosion of the 2:1 slopes occurs, then they will either cut back to 3:1 or permanently anchor the slope. 127 Cardinal Drive Extension, Wilmington, N.C. 28405-3845 • Telephone 910-395-3900 • Fax 910-350-2004 An Equal Opportunity Affirmative Action Employer tl� Mr. Stewart November 30, 1993 Stormwater Project No. 931114 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 30, 1993, 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:\WQS\STORMWAT\ADDINFO\931114.NOV cc: (2) Linda Lewis Central Files 2 DENSITY REVIEW PROJECT NAME:Wh i+eWorxl V i I �Q4e REVIEWER: A R L- PROJECT NO.: 11311 t 4- DATE: 11- 3 b - q 3 DRAINAGE BASIN: F-uI[ard Creek CLASS: SA ALLOWABLE B/U%: 25 SITE AREA= Z-3. 55 aC L=r3igeer- uses 23.53 PC ROAD AREA= Harlec&54 K/7 20/5x20 Gak Dale 415x /'S +- z (35)7- , ZCzl¢(OuZSL QG;ace Of-. Sa x 18 f (35) z. f z C. Z/46) ZS L cemel,a Circle lzc X18 -1 c(35) z t Z C. Zlbb2 Z5 z Rec/ r3uc( 1¢5x/,F .e (35% l f Z (. Zl¢G) Z5 e NUMBER OF LOTS = 54- (, 5 e-17 --rf /. 5/ a c 30,2 - (v34q = l SZ ac BUILT UPON AREA CALCULATION Built -upon Area/Lot=[(site * density) -(road area)]/N lots �(23.55 x,25) — 1.50- 54 = 353C 5T/1c>f" 351q s� 3o��=d (v P� e�f DEED RESTRICTS ALLOWABLE BUILT -UPON AREA PER LOT TO :�53.3 SF INCLUSIVE OF RIGHT-OF-WAY. COMMENTS All ��VZr en/ /'s /8 1. Need 5'lYee4 f7a�nes lisAcd below ),0P/,coble roams✓ Befell wide -why hw 9ec%i,3' s,We slopes 3:1 wless a /eife- Ao,,, D-owner 5X96"l f . 5 a orvlJla,.�, 3.! "I" ?e cry,5/,'uc%d o� s/�Pe u Y/ he pel ne7e choizd 2,-7d ma%nfa, zc/• INFORMATION REQUIRED PROVIDED REQUESTED. DEED RESTRICTIONS ✓ DENSITY SUBMITTAL FORM ✓ DENSITY CALCULATIONS ✓ NOTARIZED SUBMITTAL AUTHORIZATION ✓ VELOCITY CALCULATIONS /} SITE PLAN WITH: PROPERTY LINES ✓ STREET X-SECTION ,-my5 LOCATION MAP ✓ SWALE X-SECTION u Ar LETTER OF TRANSMITTAL •� . .�u-� GENTLEMEN: WE ARE SENDING YOU (9) PLANS ❑ COPY OF LETTER DESCRIPTION: DATE: November 19, 1993 Fj ATTACHED ❑ SPECIFICATIONS u THESE ARE TRANSMITTED AS CHECKED RELOY: ® FOR APPROVAL ❑ AS REQUESTED Mr. Dave .s _ n_ onslow County. N • . u.. - . •u ❑ UNDER SEPARATE COVER ❑ PRINTS ❑ FOR REVIEW AND -COMMENT ❑ FOR YOUR USE ❑ FOR YOUR INFORMATION ❑ FOR BIDS DUE ❑ OTHER ❑ AS FAXED TO YOUR OFFICE REMARKS ❑ NAND DELIVERED ❑ VIA OVERNIGHT MAIL COPIES TO:Mr. Jim Grant (w/enclosures) Timothy tewart, P.E. CF (P) LAM TMS/mpa (IF ENCLOSURES ARE NOT AS NOTED, KINDLY NOTIFY US AT ONCE) STORMWATER CALCULATIONS WHITEWOOD VILLAGE WHITEWOOD VILLAGE, total area = 23.53 acres Maximum percent "built upon" Maximum area "built upon" Street "built upon area" Maximum "built upon area,, remaining for lots (54) Maximum "built upon area" per lot = 25% = 5.88 acres = 1.50 acres = 4.38 acres 3,533 S.F. 35$5 'unU( NOV 2 4 1993 U DEM aoT 93 L 14- EROSION AND SEDIMENTATION CONTROL NARRATIVE TO SERVE Nnv 2 � 1993 WHITEWOOD VILLAGE OWNER: WIIITEWOOD ENTERPRISES RALEIGH, NORTH CAROLINA November 1993 STORM �16 . I� Nnv 7 4 199.3 U D E M # 3 111—�I� 11 4II - .-1 15 a4575 p f * tl h mo j PARKER AND ASSOCIATES, INC. Engineering - Surveying - Planning P.O. Drawer 976 Jacksonville, North Carolina 28541 919-455-2414 r w z L! - W Copyright ,D 1993 by Par!,er 0- A.,3scciates, Inc Au Aghts efuumm'.. NO may be rqp-ro —1 u,_.!. ir.- ili�zy nj any pi-ior written -ulont by those exprosay authoAmad, is stwky pyahjWted. w b INDEX 1. Title Page ................................................. 1 2. Index ...................................................... 1 3. Project Information Sheet .................................. 1 4. Sedimentation Control Narrative ......................... NR-1 - 7 5. Engineering Assumptions and Tables ...................... EA-1 - 2 6. Engineering Calculations ................................ EC-1 - 2 Appendix I, Financial Responsibility Form (copy) Appendix II, Density Limits for Stormwater Control (copy) PROJECT INFORMATION SHEET Whitewood Enterprises 4408 Leota Drive Raleigh, North Carolina 27603-3828 Contact Person: Mr. James B. Grant (404) 378-6055 ENGINEER: Parker and Associates, Inc. P. O. Box 976 Jacksonville, North Carolina 28541-0976 Contact Person: Timothy M. Stewart, P.E. John W. Parker, R.L.S. (919) 455-2414 SEDIMENTATION CONTROL NARRATIVE 1. PURPOSE: The purpose of this report is to provide specifications for the measures and methods proposed to control accelerated erosion and sedimentation resulting from the land disturbing activities of more than one contiguous acre in size. This report is prepared for conformance with the requirements of the Sedimentation Pollution Control Act of 1973. other regulatory program requirements are carefully considered in the site design, but this report does not assure nor imply conformance with any other rules, laws, or regulatory standards. 2. SCOPE OF WORK• This report will include a general description of existing conditions, proposed use of the site, proposed changes to the site to accomplish the proposed use, and the proposed measures to be taken for the control of accelerated erosion and sedimentation during land disturbing activities. The use of this report will require a review and familiarization with the plans and appendices, as they will clarify and supplement the narrative information. The services provided by this report are intended solely for the benefit of the Financially Responsible Person. Nothing contained herein shall confer any rights upon or create any duties on the part of the design firm toward any person other than the Financially Responsible Person. The Contractor(s) conducting the land disturbing activity, as delegated by the Financially Responsible Person, is solely responsible for the detailed means, methods, procedures, sequencing, co-ordination, job safety, and failures to carry out that work in conformance with this report, specifications, and plans. Observations and inspections by the design firm does not assume nor imply any assumption of any supervisory responsibilities by the design firm. This report shall constitute supplementary conditions for the work specified herein and if any other provisions are found to conflict with these provisions, the most restrictive provision shall apply. This report, and any specifications and plans which this report is part of or contingent to, shall be on site at all times that any of the specified work is being actively prosecuted on the site. The Sedimentation Pollution Control Act of 1973 and resulting sedimentation control programs are performance oriented. Storm water runoff events exceeding mandatory design guidelines can and do occur. The Contractor shall actively prosecute the goal of minimizing off - site sedimentation by the installation, maintenance, and amendment of measures in conformance with this report with the intent of precluding off -site accelerated sedimentation. 1 3. PROJECT DESCRIPTION: whitewood Village is a proposed 54 lot subdivision located on NCSR 1518, in Onslow County, North Carolina. This section contains approximately 23.5 acres, of which 4.4 acres will be disturbed during construction of the roads, ditches, and swales, and water and sewer installation. 4. EXISTING CONDITIONS The site is currently wooded. Based on the Onslow County Soil Maps, this site consists mostly of Torhunta fine sandy -loam in the front of the project (along NCSR 1518) and Foreston loamy fine sand soils in the back. Torhunta soils are typically very poorly drained, with 0.5 to 1.5 Seasonal High Water Table, and are moderately favorable for drainage. Foreston soils are typically moderately well drained, with 2.0 - 3.5 feet to Seasonal High Water Table, and are favorable for drainage. Both types of soils contain a high amount of fine material which need to be filtered from the runoff prior to discharge. The soil also has poor resistance to erosion of ditch banks and slopes. S. SEDIMENT CONTROL STRUCTURES AND MEASURES: The following structures, facilities, and measures are proposed for control of accelerated erosion and sedimentation. All of the specified facilities and measures may not be used on any one site or portion of a site but are provided in case of changes in work scope, unpredictable changes in site character, or ineffectiveness of the planned measures. The specifications provided for the facilities and measures should assist in determining which measures are most appropriate when additional measures are considered desirable. A. Construction Sequence: Sequencing a timely execution of construction activities is considered the most effective means for controlling accelerated erosion and sedimentation. Controlling the source of sedimenta- tion is a more efficient and cost effective approach to provid- ing for control of off -site accelerated sedimentation resulting from construction activities. The following construction sequence(s) will define the relative timeliness of installing sediment control measures and the timely stabilization of the contributing watersheds. No work shall be prosecuted until the relevant permits and approvals are obtained. Relevant permits and approvals shall include but may not be limited to: (a) water and sewer system extension approval by the N. C. Division of Environmental Health (DEH) and N.C. Division of Environmental Management (DEM), respectively; (b) storm water control approval by DEM; and (c) sediment control plan approval by the N.C. Land Quality Sec- tion (LQS) and roads and drainage approval by N.C. Department of Transportation. Prior to any land disturbing activities, a pre - construction conference should be established at a place and time acceptable to LQS personnel. NR-3 Sediment Control Construction Operation Sequence: 1. Place stabilized construction entrances at the entrances to the subdivision on Maplecrest Way from NCSR 1518. 2. Rough grade street profiles. Install sediment traps and rock check dams in the permanent road side ditches. 3. Enlarge, amend, and maintain sedimentation control measur- ers as needed for revised watershed conditions and effec- tive restraint of off -site sedimentation. 4. Install all subsurface utilities, including water, sewer, storm drainage, electrical, etc., which will be located within the street rights -of -way. Reshape any roads and ditch work that is disturbed. Place CABC, then asphalt, on roads. Install rip rap scour pads at all pipe outlets. 5. Seed and mulch or otherwise stabilize all road shoulders and ditches and all disturbed areas within 30 working days of completing any phase of construction. 6. Seed and mulch or otherwise provide protective cover sufficient to restrain accelerated erosion upon completion of construction or cessation of work, within 30 working days or 120 calendar days, whichever is less. 7. All sedimentation control devices and facilities not displaced by watershed stabilization shall be maintained at the full functional capacity until the contributing watershed is stabilized. Sediment traps shall be main- tained to at least 50% of the original installation volume until the contributing watershed is stabilized. 8. Upon final stabilization, clean out and/or fill sediment traps and remove rock check dams and inspect and maintain all rip rap scour pads. The approximate construction duration is expected to be between 4 to 6 months. Work is expected to begin imme- diately upon plan approval by LQS. B. Stabilized Construction Entrance: This facility shall be constructed as shown on the detail. It shall be placed at all locations of construction access to the project from public right-of-ways or adjacent properties. If the gravel pad is found to be ineffective, other measures such as enlarging the entrance or washing all construction vehicle tires may be required to prevent sediment tracking onto public rights -of -way or other paved areas serviced by storm drainage collection systems. As permanent stabilization is established and progresses to the interior of the project, the construction entrance or similar means shall be progressively located to remain at the interface of the construction activities in Lq 0 E progress an the project areas may also be used to stabilize the project boundaries. Silt Fences - NR-4 that are stabilized. This detail contractor staging areas inside Fabric silt fences shall be constructed as per the detail. These devices may be sued at storm drain inlets not subject to concentrated storm run-off and any other areas designated that typically do not receive diffused surface water flow in quanti- ties greater than one cubic foot per second per ten foot sections of the proposed silt fence. Silt fences shall be inspected after every rain and at intervals not exceeding one week. Accumulated sediment shall be removed and placed in approved spoils areas. Any deterioration of this device shall require immediate repair to a state of 100% functional stabili- ty. Finish Grades: All cut and fill grading shall be maintained to provide positive surface drainage throughout the construction process in the areas of the construction activities. All outlets constructed for this purpose shall be provided with sediment control devices. All cut and fill areas shall be shaped to final grade in one continuous operation. Cut and fill slopes which shall be stabilized with vegetation requiring mowing maintenance, shall be no steeper than 3:1 (horizontal: vertical). No cut or fill slopes in or immediately parallel to rights -of -ways or easements shall exceed 2:1. The side slopes of excavated trenches in cohesionless soil materials shall not exceed 2:1. All cut or fill slopes subject to concentrated storm water run-on shall be provided with diversions or slope drains to protect the slope face. Permanent Velocity Control Measures (Rip Rap Scour Pad): All storm drain outlets that exceed allowable velocities shall be provided with velocity transition facilities to minimize outlet scour. outlet velocities are determined in the manner stated in the Engineering Assumptions. The average velocities for permanent swales or channels shown on the plans are designed to be less than the. control velocity of the soil materials expected in those channels, or are provided with an erosion resistant liner. Additional engineering assumptions are specified on each applicable detail. Specific measures for this purpose may include but shall not be limited to channel linings, rip rap aprons, check dams, dissipator basins, slope drains, and permanent diversion swales. Rock check dams or treated wood check dams may be installed as permanent facilities to reduce average ditch and swale energy gradients. These facilities shall be installed in conformance with the applicable details. F. NR-5 Typical temporary velocity control devices may include but shall not be limited to check dams, temporary diversions, debris bar- riers, staked straw bales and sediment traps. Measures shall be constructed as per the applicable detail(s). Standard rock check dams may be used in permanent channels where the expected design velocities are less that 3.5 fps. Fortified rock check dams are used for velocities exceeding 3.5 fps and the stone is sized for the design velocities based on the charts in the Engineering Assumptions. Energy checks will be used in all temporary and permanent channels where the channel degradation for bare soil conditions is expected or becomes self-evident during the site development. Use of staked straw bales shall include only those situations where a filtering function is not required. Typical uses may include placement in sediment basin interiors to increase travel path tortuosity, increase sediment trap efficiency, and as temporary diversions in locations initially inaccessible by construction equipment. Sediment traps are sized and located in the manner stated in the Engi- neering Assumptions. G. Protective Ground Cover: Areas to be protected by permanent vegetative cover shall include but shall not be limited to any soil area denuded of a protective cover during the construction and not otherwise stabilized by improvements during the development construction process. Any undirected disturbed areas shall be stabilized at the expense of the Contractor. In cases using grass for permanent stabilization, the work shall include but not be limited to appropriate tilling of the area, the application of soil amendments, sowing of seed, and placing of appropriate mulch. Areas to be stabilized by landscape plantings and turf shall be installed in conformance with the landscaping and turf specifications. Areas to be seeded for grass stabilization shall be given an initial application of agricultural lime at a rate of at least 4,000 pounds per acre, superphosphate at 600 pounds per acre, and 12-4-8 grade fertilizer (or equivalent) at a rate of 600 pounds per acre, all of which shall be thoroughly mixed with the soil. After the area to be seeded is brought to proper finish grade, the entire area shall be tilled on the contour to a minimum depth of 4-inches by discing, harrowing, or other approved means. Following tillage, all large debris and stones shall be removed and the surface leveled to a smooth aspect. Dense or compacted soil areas and cut grade soil areas shall be ripped at greater than 6-inches of depth with a spring toothed ripper or similar equipment after finish grade but before tillage. Severely compacted surfaces shall be ripped to at least 12-inches of depth. No compacted soils subject to grassing for stabilization shall be covered with soil fill until ripped. Finish grades on slopes exceeding 30% shall be rough- NR-6 ened parallel to contours to maximize surface storage and minimize run-off. Upon completion of ground and soil preparation work, a grass seed mixture of 100 pounds per acre of "Rebel" fescue, 25 pounds per acre of common bermuda grass, and 10 pounds per acre of centipede grass shall be sown. Bermuda grass seed shall be in an unhulled (with hulls) condition from September 1 to April 1 and be in a hulled (without hulls) condition at all other times. Substitutions for "Rebel" fescue will be consid- ered acceptable if the substituted tall fescue variety has no ratings less than 11511 as determined by the USDA 1983 Tall Fescue Trials or more recent USDA trial data. This shall be followed by placing a suitable cover of clean grain straw or approved equivalent mulch at a rate of 1 1/2 to 2 tons per seeded area. In the case of sloping areas or other areas of more concentrated storm water run-off, the straw shall be stabilized by the application of an asphalt emulsion or other approved binding materials. Alternative methods such as hydro -seeding and hydro - mulching will be considered on an individual basis. The Contractor shall guarantee a full stand of grass over the entire seeded area. A full stand of grass will be considered acceptable when areal cover is at least 95% at a uniform minimum height of 3 inches. The Contractor shall then top -dress the stand of grass with a minimum of 300 pounds per acre of 12-4-8 fertilizer (or equivalent). Annual weed grasses and grain weeds shall not be considered part of the minimum areal cover, and seedling stands shall not be considered acceptable until the stand of specified species reaches a state of uniform post - seedling maturity. If straw mulching results in competing stands of grain, maintenance shall include mowing of the grain weed stand to a height of three (3) inches prior to reaching a height of seven (7) inches. Unacceptable grass stands shall be overseeded, after aeration by spiker, at half the original rate, as many times as necessary to establish an acceptable stand. Temporary protective cover may include solid plastic sheeting, porous mats, coarse aggregate, spraying of soil stabilizer concentrates, temporary grass cover, heavy applications of straw mulch, and other measures that protect bare soil surfaces from accelerated erosion. Commercial products shall be utilized in conformance with the manufacturers recommendations. Clean grain straw shall be applied uniformly at a minimum rate of five (5) tons per acre. Methods and measures utilized will be considered acceptable only within the specific context of the use for each individual circumstance and the effectiveness in controlling accelerated erosion. RKCIFi H. Maintenance• All erosion and sedimentation control devices and measures shall remain in place and be maintained to full functional capacity by the Contractor until the measure is displaced by permanent development features or all of the contributing watershed is stabilized to the point of no longer contributing accelerated sedimentation. All devices shall be inspected on at least a weekly basis, and maintained at 100% functional design capacity. All sediment traps and other sediment storage structures shall be maintained to at least 50% of their sediment storage capacity until watershed stabilization or removal. ENGINEERING ASSUMPTIONS A. Storm Water Discharge Outlet Protection: Outlet protection is provided where the average velocity of the ten year storm exceeds the maximum allowable velocity of the receiving soil conditions specified by the Sedimentation Control Act of 1973. The estimated storm water exit velocities and control velocities are given in the drainage data chart or applicable details. Control velocities specified by law are given in Table A. Control velocities applicable to the specific site conditions are estimated by using Table B and the UNIFIED soil classification of the site soil conditions. Outlet velocities for a given discharge were determined using Manning's Formula and Hydraulic Engineering Circular #5 (U.S. Bureau of Public Roads, 1965). For culverts that were designed for discharge rates greater than the ten year return interval storm and similar circumstances, less than full flow conditions were estimated using Table C. Charts and formulas on Table D or Rip Rap apron details were used to estimate the median diameter of stone rip rap used as velocity control measures. MANNING'S FORMULA Q = (1.486/n)(A)(R3/3)(S'/a) V = Q/A B. Storm Water Run-off Rates: The design peak discharge rates are shown on the drainage data chart or applicable details. Erosion and sedimentation control measures and devices are designed to be stable during the ten year return interval storm. If other return interval peak discharges are used, they are clearly identified on the applicable detail. The methods used to estimate peak discharge rates are referenced on the drainage data charts or applicable details. C. Stable Channel Designs: The criteria specified on pages 8.05.1 through 8.05.26 of the "North Carolina Erosion and Sediment Control Planning and Design Manual" are used as design guidelines in addition to the tables specified in Section A of this part (Storm Water Discharge Outlet Protection). Temporary channel linings are designed for channels that exceed permissible velocities specified in Table A. Permanent channel linings are designed where velocities exceed permissible velocities specified in Table E. Temporary linings may be. designed for the two or ten year return interval peak discharge. Permanent liners are designed for the ten year return interval peak discharge. Shear stress is evaluated for all flexible liners with total Td values not to exceed those specified on Table F. Computed stress values are specified on the applicable details. EA-2 D. Sediment Traps: Typical sediment trap volumes are based on � acre inch of sediment storage per year per acre of contributing watershed. Typical sediment traps do not exceed five acres of contributing watershed and are sized for an exposure duration of six months. A minimum of 33.5 cubic yards/acre sediment storage is provided with multiple containment distributed throughout the conveyance system at locations considered most critical or most efficient in sediment entrapment. Sediment traps with volumes unspecified on the plans are in addition to the design volumes for typical sediment traps and shall contain a minimum of three cubic yards of sediment storage. This type of sediment trap is for the purpose of minimizing heavy sediment trap clogging of closed storm water conduits and shall include but not be limited to culvert inlet pits, catch basin sediment traps, junction box sediment traps, and culvert outlet pits. where volumes are specified, they are not in addition to typical sediment trap design unless an exposure duration exceeding six months is specified. Where exposure durations are expected to exceed six months, a 12 month duration is assumed and a minimum of 67 cubic yards of storage volume is provided per disturbed acre. Where prevalent disturbed soil conditions are expected to be clays, silts, and loams, a minimum of 70% trapping efficiency is assumed. Where prevalent disturbed soil conditions are expected to be sands and sandy loams, a minimum of 90% trapping efficiency is assumed. The exposure duration, prevalent soil condi- tions, and size of contributing watershed is specified on the plans for each sediment trap of exposure durations exceeding 12 months. TYPICAL DITCH AND SWALE ENGINEERING CALCULATIONS - WHITEWOOD VILLAGE Section Area 0' Manninos N % Velocity Depth Top See Plans Acres CFS Bare Stabilized Grade Bare Stabilized of of for Location (Ft./Sec) (Ft./Sec) Flow Bank A -A 1.30 3.7 0.025 0.07 0.4 1.6 0.7 0.9 Stab. 2.2' +/- (Roadside Ditch) 12" Grass 0.6 Bare (Typ.) 3:1 Road Slope 2:1 Back Slope B-B 1.91 5.5 0.025 0.05 0.4 1.5 0.9 0.6 Stab. 2.0' +/- (Swale) 2" Mowed 0.5 Bare (Typ.) Grass 5:1 Side Slopes C-C 10.46 38.0 0.025 0.035 0.30 3.3 2.6 2.3 Stab. 4' +/- (Channel) Weeds 2.0 Bare 3:1 Side Slopes 1.5' Bottom NOTES: 1) These sections are typical of other channels, swales, 2) See Detail Sheet, for Construction Section Detail. 3) Calculations using Flowmaster I Version 3.3 Program, roadside ditches in the project. Utilizing Mannings Equation. COJ\WHITEWOOD.CL2 WHITEWOOD VILLAGE ENGINEERING CALCULATIONS SEDIMENT TRAP SIZING Sediment Trap Number Disturbed Area Volume ST #1 0.34 Ac. 11.3 C.Y. ST #2 0.17 Ac. 5.7 C.Y. ST #3 0.25 Ac. 8.3 C.Y. ST #4 0.25 Ac. 8.3 C.Y. ST #5 0.35 Ac. 11.7 C.Y. ST #6 0.63 Ac. 21.0 C.Y. ST #7 0.29 Ac. 9.7 C.Y. ST #8 0.06 Ac. 2.0 C.Y. ST #9 0.41 Ac. 13.7 C.Y. ST #10 0.14 Ac. 4.7 C.Y. ST #11 0.14 Ac. 4.7 C.Y. ST #12 0.37 Ac. 12.3 C.Y. ST #13 0.24 Ac. 8.0 C.Y. ST #14 0.19 Ac. 6.3 C.Y. ST #15 0.09 Ac. 3.0 C.Y. Design Standard - 66.7 C.Y. per acre per year - Assume maximum 6-month period from start of construction to final stabilization yields 33.3 C.Y. per acre per year FINANCIAL RESPONSIBILITY/OWNERSHIP FORM SEDIMENTATION POLLUTION CONTROL ACT No person may initiate any land -disturbing activity on one or more contiguous acres as covered by the Act before this form and an acceptable erosion and sedimentation control plan have been completed and approved by the Land Duality Section, N.C. Department of Environment, Health, and Natural Resources. (Please type or print and, it question is not applicable, place N/A in the blank.) Part A. 1. Project Name_ Whitewood Village 2. Location of land -disturbing activity: County____ Ons low City or Township Stump Sound __, and Highway / Street —_NCSR 1518_- 3. Apprcxlmate date land -disturbing activity wil! be commenced:_ January, 1994 4. Purpose of development (residential, commercial, industrial, etc.) :__Residential --- _ 5. Total acreage disturbed or uncovered (including off -site borrow and waste areas) : _ 4.4 Acres 6. Amount of fee enclosed $ 110.00 7. Has an erosion and sedimentation control plan been tiled ? Yes_ x No S. Person to contact should sediment control issues arise during land -disturbing activity. James B. Grant, P.E. _ relephone_ (404) 378-6055 C. Landowner (s) of Record ( Use blank page to list additional owners.): Testamentary Tigers, Inc. Name (s) 4408 Leota Drive Current Mailing Address Current Street Address Raleigh, North Carolina 27603 City State Zip City State Zip 10. Recorded in Deed Book No. 1071 Page No.. 107 Part B. 1. Person (s) or firms (s) who are financially responsible for this land -disturbing activity (Use the blank page to list additional persons or firms): Whitewood Enterprises _ Name of Person (s)or Firm (s) 4408 Leota DRive Mailing Address Street Address Raleigh, North Carolina 27603 City, — - State -- Zip -- City ----- State ---lip Teleohone (404) 378-6055 2 (a) If the Financially Responsible Party is not a resident of North Carolina give name and street address of a North Carolina Agent, A Name Mailing Address Street Address City State Zip City State Zip Telephone Telephone (b) If the Financially Responsible Party is a Partnership or other person engaging in business under an assumed name, attach a copy of the certificate of assumed name. If the Financially Responsible Party is a Corporation give name and street address of the Registered Agent. Name of Registered Agent Mailing Address Street Address City State Zip City State Zip Telephone Telephone The above information is true and correct to the best of my knowledge and belief and was provided by me under oath. ( This form must be signed by the financially responsible person if an individual or his attorney -in - fact or if not an individual by an officer, director, partner, or registered agent with authority to execute instru- ments for the finanacially responsible person ). I agree to provide corrected information should there be any change in the information provided herein. James B. Grant, P.E. Owner Type prin}!name � / Title or Authority Signature re (((//1 n , Date I Tr+Iatli T hO n 1T __, a Notary Public of the County of I�_ Rt•Y�'c, State of Na:{7a Earof rra; hereby certify that _- appeared personally before me this day and being duly sworn acknowledged that the above form was exe- cuted by him. h Wilness my hand and notarial seal, this Lrli'day of I l l� • tgr� Seal IN �'�Y 4ui>� t?cY.R,7� r�unty< ta'xr:a My commission expires My DIVISION OF ENVIRONMENTAL MANAGEMENT DENSITY X ENGINEERED PROJECT DATA Project Name Whitewood Vill Location (County, Township/Municipality, Address, State Road) ons low County Owner's Name Whitewood Enterprises Mail ingAddress- 4408 Leota Drive; Raleigh, North Carolina 27603-3828 Phone Number (404) 378-6055 Submittal Date November 19, 1993 Brief Description (include map and appropriate drawings)_ 54 Lot Subdivision with strip pavement roads and roadside Name of Water Body Receiving Stormwater Runoff Mill Creek Classification of Water Body SA If SA waters, engineered system, and distance is <0.5 miles, attach report of chloride sampling results N/A mg/1 State/Federal Permits/Approvals Required (Check appropriate blanks) CAMA Major_ 404 Permit X Other (Svecifv) CALCULATION OF BUILT UPON AREA Sedimentation/Erosion Control X DEM/DHS Sewage Disposal X Built upon area means that portion of a development that is covered by impervious or partially pervious cover including buildings, pavement, recreation facilities, gravel, etc., but not including wood decking. If the project includes areas draining to different water classifications, please note them separately below. Classification Built upon area Total Project Area % Built upon Area Allowable B/U Area Subwatershed SA 5.88 Max 23.53 Acres 25% Max. 25% Max. Subwatershed Is the Project B/U Area S the Allowable B/U Area? Yes (If no, an engineered system is required.) % Built upon area = (built upon area / total project area) * 100 Built upon area limits for projects to meet density: SA waters X- 25%, Other ---30% STORMWATER COLLECTION SYSTEM Describe how the runoff will be treated Grass -lined Swales & Ditches Office use only Is the built upon area at least 30 feet from mean high water of all surface waters? Yes _ If no, please provide a description (Note: Only boat ramps, public roads, public bridges, and walkways to water related facilities are allowed within 30 feet of the mean high water line if the project is intended to meet stornwater control requirements through density limits.) DEED RESTRICTIONS AND PROTECTIVE COVENANTS By my signature below, I certify that the recorded deed restrictions and protective covenants for this project shall limit the allowable built -upon area per lot to 3533 square feet inclusive of right-of-way, structures, pavement, walkways or patios of brick, stone, or slate, not including wood decking, state that the covenants will be binding on all parties and persons claiming under them, that they will run with the land, and that benefits may be enforced by the State of North Carolina, therefore, the covenant cannot be changed or deleted without consent of the State. CERTIFICATION I, James B. Grant, P.E. certify that the information included on this submittal form is correct, that the project will be constructed in conformance with this information, and that to the best of my knowledge, the proposed project complies with the requirements of 15 NCAC 2H.1003 (b). I authorize the below named person or firm to submit stormwater plans on my behalf, and agree to abide by the deed restriction statement above. O is Signature Bate Provide authorized person or firm name and address below: Parker & Associates, Inc. P. 0. Box 976 Jacksonville, North Carolina 28541-0976 allotaryPublicforthe Stateof Al IQn�i, l0i County' of _ 7 do hereby certify that personally ,/ appeared before me this Co day of `! l Q V. , 19 � , and acknowledges the due execution of the foregoing instrument. Witness my hand and official seal, No afy PUKt4 G dafb County, (100role My commission expires My CronT! ZµII nra r..;>ttc:;f a ,+,3as DIVISION OF ENVIRONMENTAL MANAGEMENT SIGN -OFF - Regional Office Date Date Individual Evaluating Forms/Plans Regional Water Quality Supervisor cc: Applicant/WiROBradlev Bennett/Central Files