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Home My WebLink About20190111 Ver 1_Yonkers_BMP O&M Manual_20190124Yonkers Road Improvements Bioretention Operations and Mai ntenance Man ual Prepared For: The City of Raleigh, North Carolina Public Works Department �/� pF RAlFi� y . � '� .. . _ ti� \RTN C AR�� Prepared By Rummel, Klepper & Kahl, LLP 900 Ridgefield Drive — Suite 350 Raleigh, NC 27609 (919) 878-9560 NC Firm License No. F-0112 Project Description The Yonkers Road stormwater management system includes twelve (12) bioretention cells along the corridor. These cells are located along the roadway as follows: • 3 cells in the northeast corner of the intersection of Yonkers Road and Capital Boulevard • 2 cells near the intersections of Yonkers Road and Raleigh Boulevard • 5 cells located near the Yonkers Road access to the Brentwood Road / I-440 interchange • 1 cell located 1,500 feet southeast of the Yonkers Road crossing of Marsh Creek • 1 cell in the northwest corner of the intersection of Raleigh Road and New Bern Avenue The cells are designed to hold water at a maximum 12 inch depth for a short period of time after a storm. The stored water will percolate into the filter media below the cell and drain down over the course of approximately 24-48 hours. Stormwater treatment is provided by the planting media below the cell and the vegetation within the cell. The following pages provide maintenance recommendations for bioretention cells. Construction plans for each device are also provided so that maintenance forces can see the original design and construction of the practices. Operation and Maintenance Recommendations A maintenance record for each Stormwater Control Measure (SCM) should be kept. This maintenance record will be kept in a log in a known set location. Any deficient SCM elements noted in the inspection will be corrected, repaired or replaced immediately. These deficiencies can affect the integrity of structures, safety of the public, and the pollutant removal efficiency of the SCM. Bioretention Cells: Important 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 hours after every storm event greater than 1.0 inches. Records of operation 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. SCM element Potential problems How I will remediate the roblem The entire SCM Trash/debris is resent Remove the trash/debris The perimeter of the Areas of bare soil and/or Regrade the soil if necessary to bioretention cell erosive gullies have formed. remove the gully, and then plant a ground cover and water until it is established. Provide lime and a one-time fertilizer a lication. The inlet device: pipe, The pipe is clogged (if Unclog the pipe. Dispose of the stone verge or swale a licable . sediment off-site. The pipe is cracked or Replace the pipe. otherwise damaged (if a licable . Erosion is occurring in the Regrade the swale if necessary to swale (if applicable). smooth it over and provide erosion control devices such as reinforced turf matting or riprap to avoid future roblems with erosion. Stone verge is clogged or Remove sediment and clogged covered in sediment (if stone and replace with clean applicable). stone. SCM element Potential problems How I will remediate the roblem The pretreatment system Flow is bypassing Regrade if necessary to route all pretreatment area and/or flow to the pretreatment area. ullies have formed. Restabilize the area after radin . Sediment has accumulated Search for the source of the to a depth greater than three sediment and remedy the problem inches. if possible. Remove the sediment and restabilize the pretreatment area. Erosion has occurred. Provide additional erosion protection such as reinforced turf matting or riprap if needed to revent future erosion roblems. Weeds are present. Remove the weeds, preferably by hand. Plant material Best professional practices Prune according to best show that pruning is needed professional practices. Maintain to maintain optimal plant lines of sight health. Plants are dead, diseased or Determine the source of the dying. problem: soils, hydrology, disease, etc. Remedy the problem and replace plants. Provide a one-time fertilizer application to establish the ground cover if a soil test indicates it is necessa . Weeds are present Remove the weeds, preferably by hand. If a herbicide is used, wipe it on the plants rather than srain. Bioretention cell Best professional practices Prune according to best vegetation show that pruning is needed professional practices. Maintain to maintain optimal plant lines of sight health. Plants are dead, diseased or Determine the source of the dying. problem: soils, hydrology, disease, etc. Remedy the problem and replace plants. Provide a one-time fertilizer application to establish the ground cover if a soil test indicates it is necessary. If sod was used, check to see that it was not grown in clay or impermeable soils. Re lace sod if necessa . SCM element Potential problems How I will remediate the roblem The bioretention cell: Mulch is breaking down or Spot mulch if there are only soils and mulch has floated away. random void areas. 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. Soils and/or mulch are Determine the extent of the clogged with sediment. 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 remed the roblem if ossible. An annual soil test shows Dolomitic lime shall be applied as that pH has dropped or recommended per the soil test and heavy metals have toxic soils shall be removed, accumulated in the soil disposed of properly and replaced media. with new lantin media. The underdrain, filter Clo in has occurred. Wash out the underdrain s stem. fabric element and outlet Clogging has occurred. Clean out the drop inlet. Dispose system of the sediment off-site The dro inlet is dama ed Re air or re lace the dro inlet The receiving water Erosion or other signs of Contact the NC Division of Water damage have occurred at Resources. the outlet.