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HomeMy WebLinkAboutSW4230801_Response To Comments_20240402 . •••s.%• • 5410 Trinity Road P 919.866.4951 T I M M O N S GROUP Suite 102 F 919.859.5663 YOUR VISION ACHIEVED THROUGH OURS. Raleigh, NC 27607 www.timmons.com April 2, 2024 NCDEQ STORMWATER COMMENT RESPONSES RE: Project Name: Alamance Community College Public Safety Training Center NCDEQ Stormwater Permit#: SW4230801 Project ID: SCO #19-21198-01 B Address: 2661 Sandy Cross Road, Burlington, NC 27217 Please see responses below to comments provided by Brianna Holland with NCDEQ's Winston Salem Office. 1. Redevelopment a. The design of the existing road currently disperses flow and is being replaced with a road with curb and gutter. This concentrates the flow of stormwater. Demonstrate that the definition of redevelopment is met for this portion of the site. Per G.S. 143-214.7(a1)(2),"Any land-disturbing activity that does not result in a net increase in built-upon area and that provides greater or equal stormwater control to that of the previous development." RESPONSE: The design of the proposed roadway (both Sandy Cross Rd and the main driveway) does not include curb and gutter. Curb and gutter is only proposed in the parking lot adjacent to the proposed Admin building. Both roadways will continue to disperse flow into roadside swales as it does in the existing condition. 2. Consistency: Please revise the following for consistency: a. The total drainage area to Wet Pond 1 on the table in the Application Section IV, 10 is listed as 925,169 SF, and is listed as 925,179 SF. These values should be the same. The calculations list 21.20 ac which is slightly less than both values. RESPONSE: The total drainage area to Wet Pond 1 has been updated in the table in Application Section IV, 10 to be 925,179 to match what is shown on the plans. The calculations have also been updated to reflect this drainage area to ensure there in consistency between the plans and calculations as well as to ensure that the pond is appropriately sized. 3. Supplement-EZ 2x hard copies of the complete original Supplement-EZ Form is required per Sections V & VI, 3 of the Application a. Cover Page, Line 7 —The vegetated setback is listed as 50', but it appeared that the vegetated setback provided at the existing pond is 30'. Please note 30' and 50', or revise the vegetated setbacks provided on the plans. RESPONSE: 30' (Erosion Buffer and Haw River Zone 1) and 50' (Full Haw River buffer) has been noted on the Supplement EZ Cover page line 7. b. Wet Pond Page, Line 40 —The calculations list the drawdown time as 4.1 days. RESPONSE: Wet Pond Page, Line 40 have been updated to match the drawdown time of 4.1 days. CIVIL ENGINEERING I ENVIRONMENTAL I SURVEYING I GIS I LANDSCAPE ARCHITECTURE I CONSTRUCTION SERVICES • •••411. 5410 Trinity Road P 919.866.4951 T I M M O N S GROUP Suite 102 F 919.859.5663 YOUR VISION ACHIEVED THROUGH OURS. Raleigh, NC 27607 www.timmons.com 4. Plans 2x signed& sealed hard copies of a plan sheets showing the following (This item is required per 15A NCAC 02H.1042(2)(g) and per Section VI, 8 of the Application): a. It appears 'Plan View 5' on the plans is not included in the project area. If this area should be part of the project, please update the project area accordingly. RESPONSE: The project area has been updated to be the entire leased area of 90.43-AC less the total surface water area of 4.24-AC = 86.19-AC which includes plan view 5. i. Boyd's Creek is present on 'Plan View 5', and is a surface water which requires vegetated setbacks. Show the required vegetated setbacks from the on-site surface waters in the main set of plans (Section VI, 8p). Refer to 15A NCAC 02H .1017(10) and 15A NCAC 02H .1003(4) for setback details. RESPONSE: The 50-ft haw river buffer, 30-ft erosion vegetated setback/zone 1, and 20-ft zone 2 buffers have been added to the plans. Please see sheets CO.1, C1.3, C2.2, C3.2, 5.2, and C5.5. b. Vegetated setbacks (.1003(4) & .1017(10)) must be shown on the plans (.1042(2)(g)(iii)), The provided plans don't clearly define whether the dashed line near the northern pond is meant as a setback for the pond itself or if it is a wetland buffer. To ensure clarity, it is recommended to add a callout and dimensions to the vegetated area, specifying it as the setback for the existing pond. RESPONSE: This pond was determined to be a non-jurisdictional feature and buffer shown is vegetive setback from the wetlands for erosion control purposes. Impacts within the 30-ft has been approved by the regional office. c. Per Wet Pond MDC 11 (b), the vegetated shelf shall be planted with a minimum of three diverse species of herbaceous, native vegetation at a minimum density of 50 plants per 200 square feet of shelf area. The schedule shows 260+250+250+260 = 1020 plants/4082 SF, which is less than 50 plants/200 SF. RESPONSE: The wet pond planning schedule on sheet C7.3 now shows 1,021 plants to meet the 50 plants/200 SF planting requirement. 5. Provide PDFs of all revisions, 2 hardcopies of revised plan sheets, 2 hardcopies of other documents, and a response to comments letter briefly describing how the comments have been addressed. There appeared to be an issue with the 12/8/23 upload of the stormwater narrative, the final page on the repository has an error message, and the document appears to be incomplete. a. PDFs must be uploaded using the form at: https://edocs.deq.nc.gov/Forms/SW-Supplemental-Upload b. Hard copies must be mailed or delivered to the following address: i. For FedEx/UPS: Brianna Holland CIVIL ENGINEERING I ENVIRONMENTAL I SURVEYING I GIS I LANDSCAPE ARCHITECTURE I CONSTRUCTION SERVICES . •••s•. • 5410 Trinity Road P 919.866.4951 T I M M O N S GROUP Suite 102 F 919.859.5663 YOUR VISION ACHIEVED THROUGH OURS. Raleigh, NC 27607 www.timmons.com 512 N. Salisbury Street, Office 640E Raleigh, NC 27604 ii. For USPS: Brianna Holland 1612 Mail Service Center Raleigh, NC 27699-1612 iii. Hand Delivery: Please reach out to me prior to hand delivering a submission to make sure that I (or someone else in my group) will be able to receive the submission. Do not leave the package in the foyer with the security guard. NOTE: Hard copies should not be sent to a Regional Office. Doing so will delay the review process and the submission package may be lost while being sent from the Regional Office to me in the Central Office. RESPONSE: PDF's of all revisions, 2 hard copies of the revised plan sheets, 2 hardcopies of other documents, and a comment response letter has been provided. Sincerely, Garrett Frank, PE, PLA Project Manger Timmons Group CIVIL ENGINEERING I ENVIRONMENTAL I SURVEYING I GIS I LANDSCAPE ARCHITECTURE I CONSTRUCTION SERVICES