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Home My WebLink About20120280 Ver 1_More Info Received_20120604N W E BURDETTE LAND CONSULTING, INC 10212 Creedmoor Road Raleigh North Carolina 27615 Telephone (919) 841 9977 — Fax (919) 841 9909 S June 4 2012 Mr Ian McMillan 401 Oversight/Express Permitting Unit NC Division of Water Quality 512 Salisbury Street Raleigh, North Carolina 27604 RE Additional Information Response The Marketplace at Tramway Tramway Lee County, North Carolina NCDWQ Project # 12 0280 USACE AID # SAW 2011 01375 BLC Project # 11404 Dear Mr McMillan and Ms Gibby Ms Jean Gibby Raleigh Regulatory Field Office US Army Corps of Engineers 3331 Heritage Trade Drive Wake Forest North Carolina 27587 We received NC Division of Water Quality's ( NCDWQ) requests for more information on the subject project dated April 18 2012 Mr Jeremy Thomas, the project engineer has reviewed each these comments and provided the response following a restatement of the request 1 Please revise the emergency spillway design so that large storms do not discharge over the proposed level spreader The stormwater wet detention basin is designed to meet 90% TSS removal so no vegetated level spreader is required by NCDWQ The purpose of the proposed level spreader is to help spread flow discharged from the spillways before releasing to the downstream natural drainage system The proposed level spreader will be lined with Class 1 np rap (2 thick) and the voids grouted to make the lining more resistant to erosion and displacement Also there is a plunge pool designed dust upstream of the proposed level spreader, to further aid in energy dissipation and spreading the flow The emergency spillway is currently proposed in an area of the pond where the spillway channel can be cut into the existing ground If the spillway were to be relocated to another area along the berm, the spillway channel would be installed in fill — increasing the Mr McMillan & Ms Gibby BLC Project # 11404 June 4 2012 Page 2 of 2 likelihood of erosion and possibly jeopardizing the structural integrity of the earthen berm If the emergency spillway were to remain in the area as proposed but not curved toward the level spreader, it would be directed toward the adjacent property not within the natural drainage system Activation of the emergency spillway and resulting flow over the adjacent property may result in undue property damage Based on the explanation provided above, I respectfully request the emergency spillway design remain as proposed 2 Please provide a signed and notarized Operation and Maintenance Agreement for the proposed wet detention pond A signed and notarized Operation and Maintenance Agreement for the proposed wet detention pond is attached Please do not hesitate to contact us if you have any questions require additional information or would like to schedule a meeting to discuss the application Sincerely Burdette Land Consulting Inc G`, Z Jennifer A Burdette Environmental Specialist Attachments c Craig Brown USACE Bobby Branch — BA Properties LLC Mark Lyczkowski — ML Consulting Jeremy Thomas — J Thomas Engineering Inc Permit Number (to be provided by DWQ) Drainage Area Number Wet Detention Basin Operation and Maintenance Agreement I will keep a maintenance record on this BMP This maintenance record will be kept in a log in a known set location Any deficient BMP elements noted in the inspection will be corrected repaired or replaced immediately These deficiencies can affect the integnty of structures, safety of the public and the removal efficiency of the BMP The wet detention basin system is defined as the wet detention basin, pretreatment including forebays and the vegetated filter if one is provided This system (check one) ❑ does ® does not This system (check one) R does ® does not incorporate a vegetated filter at the outlet incorporate pretreatment other than a forebay Important maintenance procedures - Immediately after the wet detention basin is established, the plants on the vegetated shelf and perimeter of the basin should be watered twice weekly if needed until the plants become established (commonly six weeks) - No portion of the wet detention pond should be fertilized after the first initial fertilization that is required to establish the plants on the vegetated shelf — Stable groundcover should be maintained in the drainage area to reduce the sediment load to the wet detention basin — If the basin must be dramed for an emergency or to perform maintenance the flushing of sediment through the emergency dram should be minimized to the maximum extent practical — Once a year a dam safety expert should inspect the embankment After the wet detention pond is established it should be inspected once a month and within 24 hours after every storm event greater than 10 inches (or 15 inches if in a Coastal County) Records of operation and maintenance should be kept in a known set location and must be available upon request Inspection activities shall be performed as follows Any problems that are found shall be repaired immediately BMP element Potential problem How I will remediate the problem The entire BMP Trash debris is present Remove the trash /debris The perimeter of the wet Areas of bare soil and /or Regrade the soil if necessary to detention basin 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 application Vegetation is too short or too Maintain vegetation at a height of long approximately six inches Form SW401 Wet Detention Basin O &M Rev 4 Page 1 of 4 Permit Number (to be provided by DWQ) Drainage Area Number BMP element Potential problem How I will remediate the problem The inlet device pipe or The pipe is clogged Unclog the pipe Dispose of the swale sediment off site The pipe is cracked or Replace the pipe otherwise damaged Erosion is occurring in the Regrade the swale if necessary to swale smooth it over and provide erosion control devices such as reinforced turf matting or riprap to avoid future prob lems with erosion The forebay Sediment has accumulated to Search for the source of the a depth greater than the sediment and remedy the problem if original design depth for possible Remove the sediment and sediment storage dispose of it in a location where it will not cause impacts to streams or the BMP Erosion has occurred Provide additional erosion protection such as reinforced turf matting or rlprap if needed to prevent future erosion problems Weeds are present Remove the weeds preferably by hand If pesticide is used wipe it on the plants rather than spraying The vegetated shelf Best professional practices Prune according to best professional show that pruning is needed practices to maintain optimal plant 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 Weeds are present Remove the weeds preferably by hand If pesticide is used wipe it on the plants rather than spraying The main treatment area Sediment has accumulated to Search for the source of the a depth greater than the sediment and remedy the problem if original design sediment possible Remove the sediment and storage depth dispose of it m a location where it will not cause impacts to streams or the BMP Algal growth covers over Consult a professional to remove 50% of the area and control the algal growth Cattails phragmites or other Remove the plants by wiping them invasive plants cover 50% of with pesticide (do not spray) the basin surface Form SW401 Wet Detention Basin O &M Rev 4 Page 2 of 4 Permit Number (to be provided by DWQ) Drainage Area Number BMP element Potential problem How I will remediate the roblem The embankment Shrubs have started to grow Remove shrubs immediately on the embankment Evidence of muskrat or Use traps to remove muskrats and beaver activity is present consult a professional to remove beavers A tree has started to grow on Consult a dam safety specialist to the embankment remove the tree An annual inspection by an Make all needed repairs appropriate professional shows that the embankment needs repair if applicable) The outlet device Clogging has occurred Clean out the outlet device Dispose of the sediment off site The outlet device is damaged Repair or replace the outlet device The receiving water Erosion or other signs of Contact the local NC Division of damage have occurred at the Water Quality Regional Office or outlet. the 401 Oversight Unit at 919 733 1786 The measuring device used to determine the sediment elevation shall be such that it will give an accurate depth reading and not readily penetrate into accumulated sediments When the permanent pool depth reads 3 7 feet in the main pond, the sediment shall be removed When the permanent pool depth reads 3 7 feet in the forebay the sediment shall be removed BASIN DIAGRAM ill in the blanks) p Permanent Pool Elevation 479 7 Sediment Removal 476 Pe amen Pool - - Volume Sediment Removal Elevation 476 Volume Bottom Elevatio 475 ft Min -- - - - -- - Sediment Bottom Elevation 475 1 ft Storage Sedimer FOREBAY MAIN POND Storage Form S W401 Wet Detention Basin O &M Rev 4 Page 3 of 4 Permit Number (to be provided by DWQ) I acknowledge and agree by my signature below that I am responsible for the performance of the maintenance procedures listed above I agree to notify DWQ of any problems with the system or prior to any changes to the system or responsible party Project name MARKETPLACE AT TRAMWAY BMP drainage area number 01 Print name Bobby Branch Title Property Owner Address 402 Forestwood Park Road, Sanford NC 27330 Phone 919 -774 1525 Signature Date `J Ja Note The legally responsible party should not be a homeowners association unless more than 50% of the lots have been sold and a resident of the subdivision has been named the president - fQ 'L,,., a Notary Public for the State of of J!W�Qdp'yj-, do hereby certify that personally appeared before me this .24th - day of g6U4� 2012 and acknowledge the due execution of the forgoing wet deMtion basin maintenance requirements Witness my hand and official seal �E6Y Tq y A `� MC ?2 +uu ++ SEAL My commission expiresMaA �,� 21, 2-0' Form SW401 Wet Detention Basin O&M Rev 4 Page 4 of 4