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HomeMy WebLinkAbout20070081 Ver 2_More Info Received_20070720 (2)KELLER ENVIRONMENTAL ENVIRONMENTAL CONSULTANTS 7921 Haymarket Lane, Raleigh, NC (919)844-7437 Fax (919)8447438 LETTER OF TRANSMITTAL TO: NC Division of Water Quality WE ARE SENDING YOU THE FOLLOWING: ^ Pre-construction Notification (PCN) ^ Plans ® Documents ^ Other ~x,p o~-oo$~ V2 ~~~ ,~~~- DATE: July 20, 2007 ~~ ; ~ ~. ~ ~~ ~' al~,~ ~ ~~ ~ ~ ATTENTION: DWQ EXPRESS TEAM `~`~~ ~ ~ d,:d ~OOI RE: Cedar Ridge O & M Manual ~~~~'~:'~~~,~~~?'S~~~k c.~tJ~~i i~y° ' ` ~'-yq q gR,4AlLh ^ Maps ^ Specifications THESE ARE TRANSMITTED AS CHECKED BELOW: ® For approval ®As requested ^ For review & comment ^ Please reply ^ See below ® For your files ^ Regular Mail ^ Fed-Ex ®Delivered by KE ^ Picked Up COPIES DATE DESCRIPTION 1 Cedar Rid e O & M Manual Remarks: THANK YOU! ~a~ Recd By: Signed STORMWATER OPERATION & MAINTENANCE MANUAL AND BUDGET FOR BIO RETENTION AREAS IN CEDAR RIDGE SUBDIVISION PHASES 2, 3, 4 & 5 Prepared by: Aiken & Yelle Associates, PA 3755 Benson Drive Raleigh, NC 27609 ~.kp ~'1-no$t V~ OPERATIONS AND MAINTENACE MANUAL SECTION I- INTRODUCTION: This manual establishes procedures for maintenance and operation of stormwater in accordance with the guidelines as set forth in the NCDWQ Stormwater Management Design Manual. The NCDWQ rules require that stormwater devices be inspected annually and that they be maintained in accordance with this document. Any repairs that become necessary as a result of periodic inspections shall be completed within thirty (30) calendar days of filing the report unless written approval of and extension is obtained from the Town of Rolesville or NCDWQ. The storm water management plan for this site consists of only water quality Bio Retention areas. The Bio Retention areas are to serve as a bio-filtration to reduce the nitrogen loading from the proposed impervious surface. This development will be developed in four phases as approved by the Town of Rolesville as depicted on the preliminary site plan on file in the Town of Rolesville Planning Department. All phases 1 will be developed in accordance with construction drawings entitled "Cedar Ridge Subdivision", prepared by Aiken & Yelle Associates, PA, dated July 9, 2007 and approved by Town of Rolesville Central Engineering Division. Therefore the water quality Bio Retention areas will also be installed by phases. The Bio Retention areas to be constructed by phases are as follows: A. Phase 2 Phase 2 of this development plan includes the construction of one (1) water quality Bio Retention area as shown on the "Cedar Ridge Subdivision- Phase 2, 3, 4 and 5 Construction Drawings", prepared by this firm, dated 07/09/07. Bio Retention area #1 will be constructed within a public drainage easement on Lot 111 of the proposed subdivision. More specifically the Bio Retention area will be located down stream from storm sewer manhole #73. The Bio Retention surface area required is be 800 SF (approx. 81 feet in length and 16 feet in width) with side slopes of 3 (H): 1'(V) and a depth of 1 foot. B. Phase 3 Phase 3 of this development plan includes the construction of one (1) water quality Bio Retention area as shown on the "Cedar Ridge Subdivision- Phase 2, 3, 4 and 5 Construction Drawings", prepared by this firm, dated 07/09/07. Bio Retention area #11 will be constructed on Lots 65 & 66 of the proposed subdivision. More specifically the Bio Retention area will be located down stream from storm sewer manhole #2 (SMH#2). The Bio Retention surface area required is Page 2 of 14 1,100 SF (aprox. 50 feet in length and 28 feet in width) with side slopes of 3 (H): 1'(V) and a depth of 1 foot. C. Phase 4 Bio Retention area #2 will be constructed within a designated open space area proposed for this subdivision. More specifically the Bio Retention area will be located down stream from storm sewer manhole #61B (SMH#61B). The Bio Retention surface area will be 1,500 SF (approx. 62 feet in length and 35 feet in width) with side slopes of 3 (H): 1'(V) and a depth of 1 foot. Bio Retention area #3 will be constructed within a designated open space area proposed for this subdivision. More specifically the Bio Retention area will be located down stream from storm sewer manhole #64 (SMH#64). The Bio Retention surface area will be 400 SF (approx. 38 feet in length and 12 feet in width) with side slopes of 3 (H): 1'(V) and a depth of 1 foot. Bio Retention area #4 will be constructed within a public drainage easement on Lot 100 of the subdivision. More specifically the Bio Retention area will be located down stream from storm sewer manhole #57 (SMH#57). The Bio Retention surface area will be 1,600 SF (approx. 140 feet in length and 12 feet in width) with side slopes of 3 (H): 1'(V) and a depth of 9 inches. Bio Retention area #5 will be constructed within a public drainage easement on Lot 94 of the subdivision. More specifically the Bio Retention area will be located down stream from storm sewer manhole #51 (SMH#51). The Bio Retention surface area will be 1,000 SF (approx. 60 feet in length and 22 feet in width) with side slopes of 3 (H): 1'(V) and a depth of 1 foot. - Bio Retention area #6 will be constructed within a public drainage easement on Lot 87 of the subdivision. More specifically the Bio Retention area will be located down stream from storm sewer manhole #40 (SMH#40). The Bio Retention surface area will be 600 SF (approx. 38 feet in length and 17 feet in width) with side slopes of 3 (H): 1'(V) and a depth of 1 foot. Bio Retention area #7 will be constructed within a public drainage easement on Lot 80 of the subdivision. More specifically the Bio Retention area will be located down stream from storm sewer manhole #33 (SMH#33). The Bio Retention surface area will be 1,050 SF (approx. 56 feet in length and 24 feet in width) with side slopes of 3 (H): 1'(V) and a depth of 1 foot. Bio Retention area #8 will be constructed within a public drainage easement on Lot 70 of the subdivision. More specifically the Bio Retention area will be located down stream from storm sewer manhole #24 (SMH#24). The Bio Retention surface area will be 1,300 SF (approx. 69 feet in length and 21 feet in width) with side slopes of 3 (H): 1'(V) and a depth of 1 foot. Page 3 of 14 Bio Retention area #9 will be constructed within a designated open space area proposed for this subdivision. More specifically the Bio Retention area will be located down stream from storm sewer manhole #13 (SMH#13). The Bio Retention surface area will be 675 SF (approx. 44 feet in length and 18 feet in width) with side slopes of 3 (H): 1'(V) and a depth of 1 foot. Bio Retention area #10 will be constructed within a designated open space area proposed for this subdivision. More specifically the Bio Retention area will be located down stream from storm sewer manhole #10 (SMH#10). The Bio Retention surface area will be 400 SF (approx. 35 feet in length and 14 feet in width) with side slopes of 3 (H): 1'(V) and a depth of 1 foot. D. Phase 5 Bio Retention area #12 will be constructed within a public drainage easement on Lot 156 of the subdivision. More specifically the Bio Retention area will be located down stream from storm sewer manhole #38 (SMH#38). The Bio Retention surface area will be 625 SF (approx. 52 feet in length and 14 feet in width) with side slopes of 3 (H): 1'(V) and a depth of 1 foot. SECTION II- WATER QUALITY BIO RETENTION AREA MAINTENANCE REQUIREMENTS: 1. Watering: Plants should be selected to be tolerant of the bioretention facility's particular conditions. Watering should not be required after establishment (about 2 to 3 years). However, watering may be required during prolonged dry periods after plants are established. 2. Erosion Control: Inspect flow entrances, ponding area, and surface overflow areas periodically. Replace soil, plant material, and/or mulch in areas where erosion has occurred. Erosion problems should not occur with proper design except during extreme weather events. If erosion problems do occur, the following issues should be re-assessed: flow volumes from the contributing drainage area and bioretention size; flow velocities and gradients within the bioretention facility; flow dissipation and erosion protection methods in the pretreatment and in-flow areas. If sediment is deposited in the bioretention facility, immediately determine the source, remove excess deposits, and correct the problem. 3. Plant Material: Depending on plants selected and aesthetic requirements, occasional pruning and removal of dead plant material may be necessary. Replace all dead plants. However, if specific plants consistently have a high mortality rate, assess the cause and replace with appropriate species. Periodic weeding is necessary until groundcover plants are established. Weeding should become less frequent if an appropriate plant density has been used. 4. Nutrients and Pesticides: The soil media and plant material should have been Page 4 of 14 selected for optimum fertility, plant establishment, and growth within the particular conditions of each bioretention facility. Nutrient and pesticide inputs should NOT be required and will degrade the pollutant processing capability of the bioretention facility, as well as contribute to additional pollutant loading to receiving waters. By design, bioretention facililities are typically specified in watersheds where phosphorous and nitrogen levels are often elevated. Therefore, these should not be limiting nutrients with regard to plant health. If in question, have the soil analyzed for fertility. 5. Mulch: Replace mulch annually in bioretention facilities where heavy metal deposition is likely (e.g., drainage areas that include commercial/industrial uses, parking lots, or roads). In residential or other settings where metal deposition is not a concern, replace or add mulch as needed to maintain a 2 to 4 inch depth at least once every two years. 6. Soil media: Soil mixes for bioretention facilities are design to maintain long-term fertility and pollutant processing capability. Estimates from metal attenuation research indicates that metal accumulation should not present a toxicity concern for at least 20 years in bioretention facilities (USEPA 2000). Further, replacing mulch where heavy metal deposition is likely provides an additional factor of safety for prolonged bioretention performance. If in question, have soil analyzed for fertility and pollutant levels. When the filtering capacity diminishes substantially (e.g., when water ponds on the surface for more than 12 hours), remedial actions must be taken. One possible problem is that underdrain pipe systems can become clogged. Annual flushing through pipe cleanouts is recommended to facilitate unclogging of the pipes without disturbing the bioretention areas. If the water still ponds for more than 12 hours, the top few inches of material should be removed and replaced with fresh material. The removed sediments should be disposed of in an acceptable manner (e.g., landfill). If that does not solve the problem, more extensive rebuilding is required. Examples of When to Perform Maintenance Thin Mulch in the Bioretention Cell ^ Remove top layer of fill media when the pool does not drain quickly. The pool is designed to drain within 12 hours. Operation and Maintenance procedures: - Immediately after the bioretention cell is established, the plants will be watered twice weekly if needed until the plants become established (commonly six weeks). -Snow, mulch or any other material will NEVER be piled on the surface of the bioretention cell. -Heavy equipment will NEVER be driven over the bioretention cell. -Special care will be taken to prevent sediment from entering the bioretention cell. - Once a year, a soil test of the soil media will be conducted. After the bioretention cell is established, I will inspect it once a month and within 24 Page 5 of 14 hours after every storm event greater than 1.0 inches. Records of inspection and maintenance will be kept in a known set location and will be available upon request. Inspection activities shall be performed as follows. Any problems that are found shall be repaired immediately. ~nsoection ana iviamtenance rrovisi~n5 ~u~ ~wiC~Ciiuvii r~~a~ BMP element Potential problems How to remediate the roblem The entire BMP Trash/debris is present Remove the trash/debris The perimeter of the Areas of bare soil and/or Regrade the soil if bioretention cell erosive gullies have necessary toremove the formed. gully, and then plant .aground cover and water until it isestablished. Provide lime and aone- time fertilizer a lication. The inlet device: pipe, zThe pipe is clogged (if Unclog the pipe. Dispose stone verge or swale applicable). of the sediment off-site. The pipe is cracked or otherwise damaged (if applicable). Erosion is occurring in the swale (if applicable). Stone verge is clogged or covered in sediment (if applicable) Replace the pipe. Regrade the swale if necessary to smooth it over and provide erosion control devices such as reinforced turf matting or riprap to avoid future problems with erosion. Remove sediment and clogged stone and replace with clean stone. _~:_. _ 'ns ection and Maintenance Nrovisions for tsioretention Hreas c~nunueu BMP element::: Potential problems How to remediate the problem Page 6 of 14 The pretreatment area Flow is bypassing Regrade if necessary to pretreatment area route all flow to the and/or gullies have pretreatment area. formed. Restabilize the area after radin Sediment has Search for the source of accumulated to a depth the sediment and greater than three remedy the problem if inches. possible. Remove the sediment and restabilize the retreatment area. Erosion has occurred. Provide additional erosion protection such as reinforced turf matting or riprap if needed to prevent future erosion roblems. Weeds are present Remove the weeds, preferably by hand. The bioretention cell: Best professional Prune according to best Vegetation practices professional show that pruning is practices. needed to maintain optimal plant health. Plants are dead, Determine the source of diseased or~ theproblem: soils, dying. hydrology, disease, etc. Remedy the problem and replace plants. Provide aone-time . fertilizer application to establish the ground cover if a soil test indicates it is necessa Tree stakes/wires are Remove tree stake/wires present (which can kill the tree if six months after not removed). plantin . Page 7 of 14 The bioretention cell: Mulch is breaking down Spot mulch if there are soils and mulch or only random void areas. has floated away. Replace whole mulch layer if necessary. Remove the remaining much and replace with triple shredded hard wood mulch at a maximum depth of three inches. The bioretention cell: Soils and/or mulch are .Determine the extent of soils and mulch clogged with .sediment. the clogging-remove and replace either just the top layers or the entire media as needed. Dispose of the spoil in an appropriate off-site location. Use triple shredded hard wood mulch at a maximum depth of three inches. Search for the source of the sediment and remedy the problem if possible An annual soil test Dolomitic lime shall be shows that - applied as pH has dropped or recommended per the heavy soil test and toxic soils metals have shall be removed, accumulated in disposed of properly and the soil media. replaced with new lantin media. The underdrain system Clogging has occurred Wash out the underdrain (if applicable system The drop inlet Clogging has occurred Clean out the drop inlet. Dispose of the sediment off-site. The drop inlet is Repair or replace the damaged drop inlet. The receiving water Erosion or other signs of Contact the NC Division damage have occurred of Water Quality 401 at the outlet. Oversight Unit at 919- 733-1786. Page 8 of 14 SECTION V: OPERATION A. Record Keeping Operation of the storm water maintenance device should include recording of the following: • Annual Inspection Reports- Inspections should be conducted. A professional engineer or his/her representative should conduct the inspection. Reports should be kept on file with the Homeowner's Association and a copy given to the Central Engineering Division of the Town of Rolesville. • Observations- All visual observations should be recorded. Where periodic visual inspections are performed following significant rainfall events (2" of rainfall in 24 hours or greater event), these inspections should be logged into the Periodic Inspections, Operation & Maintenance Form in Section X of this manual. • Maintenance- Written reports of maintenance and/or repairs should be recorded on the Periodic Inspections, Operation & Maintenance Form in Section X of this manual. B. Other Operational Procedures The Owner's Association should maintain a complete and up-to-date set of plans (as-built drawings) and all changes made to the storm water maintenance devices over time should be recorded on the as-built plans. SECTION VI: BUDGET A. Annual Budget- Water Quality Bio Retention areas 1-12 Annual Inspection & Report Registered Engineer 1 visit @ 8hrs/visit x $90/hour= $ 800.00 Miscellaneous Visits= $ 500.00 Maintenance Cost for mowing, seeding fertilizing And trash removal (2xs annual) $ 600.00 Sediment cost removal (every 5 years) annualized cost $ 600.00 Total Annual Budget (Water Quality Grass Lined Bio Retention areas= $2,500.00 Page 9 of 14 Water Quality Grass Line Bio Retention B, Total of Construction Cost for areas. Water ualit Bio Retention areas _ $ 72000.00 @ $6,000/peT _ $ 332.00 $ 0.501LF $ 72332.00 Bio Retention areas 12 = 664 LF Sub-total Seedin ter Quality Grass Line Bio Retention areas: Total Constructio0n Cost for Wa $72,332.0 of14 WATER QUALITY BIO RETENTION AREA INSPECTION CHECKLIST CEDAR RIDGE SUBDIVISION SUBDIVISION 1NSPECTOR/(S): DATE: WEATHER: TIME: q WATER QUALITY BIO RETENTION AREA ACTION U ~ aw. v "' x z Ud CHECK/CIRCLE CONDITION NOTED OBSERVATION a x z °z x aQ. ~ x ~ z ~ H F W ~ Bio Retention area # Location: Vegetation Erosion Sediment Trash Bio Retention area # Location: Vegetation Erosion Sediment Trash Bio Retention area # Location: Vegetation/ cover Erosion Sediment Trash Bio Retention area # Location: Vegetation/ cover Erosion Sediment Trash Bio Retention area # Location: Vegetation/ cover Erosion Sediment Trash Bio Retention area # Location: Vegetation/ cover Erosion Sediment Trash GENERAL COMMENTS, SKETCHES & FIELD MEASUREMENTS: Page 11 of 14 CEDAR RIDGE SUBDIVISION SUBDIVISION WATER QUALITY BIO RETENTION AREAS PERIODIC INSPECTION, OPERTIAON AND MAINTENANCE REECORDS RAIN WEATHER GENERAL DATE TIME (in.) CONDITIONS OBSERVATIONS OR RECORDED BY COMMENTS DATE MAINTENANCE PERFORMED COMMENTS RECORDED BY Page 12 of 14 MAINTENANCE AGREEMENT Project: Cedar Ride Subdivision Responsible Parry: Cedar Ridge Subdivision Homeowners' Association Address: 8804 Albright Drive Raleigh North Carolina 919-614-1733 I. Monthly Inspection- A. Visual inspection for signs of erosion after cone-inch or more rainfall event over a 24-hour period to determine if any appreciable damage occurred which would require repair to the stormwater device. B. Remove thrash and debris from inlets and outlets, emergency spillways and Bio Retention areas. II. Quarterly Inspections and Maintenance: A. Same as the monthly described above. III. Semi-Annually and Maintenance: A. Same as quarterly inspection B. Grassing and mowing as required. Mowing as needed when grass is over 8" tall. C. Reseed or re-vegetate disturbed vegetative areas. IV. Annual Inspection and Maintenance: A. Same as quarterly and semi-annual inspections. B. Registered Engineer inspects and confirms that the stormwater devices are operating properly and are in good physical condition. A copy of the inspection reports in Section X of this report shall be submitted to the Central Engineering Department of the Town of Rolesville. The date set as a deadline to perform this annual inspection is one year after the date the as-built drawings were first certified to the Town of Rolesville. C. Sediment shall be removed if it is impeding the water flow.. Page 13 of 14 V. General Maintenance: A. Mowing of Bio Retention areas according to the season. Maximum grass height of 4-6 inches. B. In case the ownership of the Impoundment transfers, the current owner shall within thirty (30) days of transfer of ownership, notify the Town of Rolesville Engineering Department, Stormwater Management Division of such ownership transfer. C. This property and impoundment is also subject to the Stormwater Operation and Maintenance Manual and budget filed relative to this project. D. All trash and debris removal should occur as needed. The pond should be inspected for trash and debris monthly. I, t2obert t~alc-nco ,for ~CdsC I~~d~a~t L,crrJC~e~~~+ne~F'll~ hereby acknowledge that I, or my assigns, are the financially responsible party for maintenance of these water quality Bio Retention areas. I or my assigns will perform the maintenance as outlined in this document. Signature: Date: 6 Company/Partnership: CCd4f ~tc~t ~..,~~ I~<,~I ~e~ t,LC I, ~+b` ~ .. i D~ , a Notary Public for the State of GJdt~LP_ ,County of ~y~~.~ L-,d,r„t ~„Q, do hereby certify that ~ ablfk 'Q e1 an G o Personally appeared before me this day of , 20 0?, and acknowledge the due execution of the foregoing instrument. Witness my hand and official seal, (SEAL) KELLY E. PIERCE NOTARY PUBLIC WAKE COUNTY, N.C. My Commission Expires 4-18-2012. Notary My commission expires ~ ' .~ 0102., Page 14 of 14