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Home My WebLink About20201125 Ver 1_More Info Requested_20200925Strickland, Bev From: Yankura, Kaylie Sent: Friday, September 25, 2020 4:23 PM To: Jon Swaim; Kyle Seaman Cc: Brown, David W CIV USARMY CESAW (USA); Leslie, Andrea J; Moore, Andrew W Subject: Request for Additional Information — Horsepasture River WWTP and Collection System Improvements; DWR# 20201125 Mr. Swaim, On August 31, 2020, the Division of Water Resources (Division) received your application requesting a 401 Water Quality Certification from the Division for the subject project. The Division has determined that your application is incomplete and cannot be processed. The application is on hold until the following items are addressed: 1. The PCN states that the 30" culvert associated with impact S2 will be buried 6 inches into the streambed. Please provide cross section details showing the provisions for aquatic life passage for permanent culvert installation. This information should be shown on the construction drawings for contractor reference. [15A NCAC =mIffl 2. Per General Condition 11.9 of GC 4135, all work must be done "in the dry'. Therefore, dewatering methods will be necessary to temporarily dewater the stream channel during pipe installation. The application states that work will occur in the dry, but does not specifically address how this will be accomplished. Please provide a construction sequence that details the method of dewatering to be utilized at the site and the sequence of construction events to be followed to ensure compliance with this condition. In addition, please ensure that the location of temporary impacts associated with the proposed dewatering/pump around method are shown on the construction drawings and that associated temporary impacts are clearly indicated in the PCN impact table (e.g. temporary fill for coffer dams, jersey barriers, etc.). [15A NCAC 02H .0506 (b)(2)] 3. Please confirm if the culvert alignment associated with the proposed 72 linear feet of temporary stream impact S1 has been appropriately designed to form a perpendicular stream crossing. I am concerned that the outlets of the proposed alignment will disproportionately direct stream flow and cause downstream channel instability. Please provide information supporting the proposed design and indicate how downstream degradation will be avoided. Please also indicate what design alternatives have been considered for the crossing (e.g. the use of less, larger diameter culverts, etc.). [15A NCAC 02H .0506 (b)] 4. Please indicate if riprap dissipater pads are a component of the culvert installation associated with temporary stream impact S1. If so, please include the use of riprap dissipater pads on the submitted plans. [15A NCAC 02H .0506 (b)(1)] 5. Please evaluate the proposed use of #57 washed stone/surge stone associated with stream impact S1, per the details included on Sheet C-217. The use of larger stone as backfill may be more effective at preventing stone washout and transport downstream. [15A NCAC 02H .0506 (b)(3)] 6. The permit application indicates that concrete will be used to reinforce riprap installed on the streambank associated with temporary stream impact S1 and on the temporary roadbed. Please indicate what best management practices will be utilized to ensure that concrete does not impact surface waters during preparation and application. [15A NCAC 02H .0502 (c)] [15A NCAC 02H .0506(b)(2) and (3)] 7. Temporary stream crossings are intended for short-term use. Please indicate the proposed timeline regarding use of the temporary stream crossing associated with impact S1. [15A NCAC 02H .0502 (c)] 1 8. Condition 11.11. of 401 General Water Quality Certification 4135 requires that "Installation of culverts in wetlands shall ensure continuity of water movement and be designed to adequately accommodate high water or flood conditions. When roadways, causeways, or other fill projects are constructed across FEMA-designated floodways or wetlands, openings such as culverts or bridges shall be provided to maintain the natural hydrology of the system as well as prevent constriction of the floodway that may result in destabilization of streams or wetlands." Sheet C-209 submitted with the PCN appears to depict a stormwater pipe connecting the western portion of Wetland C to the eastern portion of Wetland C. However, it is difficult to determine from the details on Sheet C-210 whether the pipe will be installed at an elevation that ensures continuity of water movement. It appears the invert of the pipe is proposed to be set at an elevation above existing ground. Please provide additional details regarding how the referenced condition will be met including proposed elevation of existing ground and pipe invert elevation. [15A NCAC 02H .0506 (b)(2)] 9. Please provide a qualitative indirect and cumulative impact analysis for the project. [15A NCAC 02H .0506(b)(3)] Please see the Division's policy for guidance on our website at: https://fi les. nc.gov/ncdeq/Water% 20Qual ity/Surface % 20Water/ 20Protection/401/Policies—Gu ides —Ma nua Is/C umulativelmpactPolicy.pdf. Note that the Division is in receipt of the TWSA-WWTP —Water Resources Cumulative Impact Analysis provided with the PCN. However, the provided document does not complete the analysis as required by the Division's policy. Pursuant to Title 15A NCAC 02H .0502(c), the applicant shall furnish all of the above requested information for the proper consideration of the application. If all of the requested information is not received, the Division will be unable to approve the application and it will be returned. Please contact me if you have any questions. You may provide your response via email or mail to the address below. Thank you, Kaylie Yankura Environmental Specialist —Asheville Regional Office Water Quality Regional Operations Section NCDEQ — Division of Water Resources 2090 U.S. Hwy. 70 Swannanoa, N.C. 28711 828 296 4685 office 828 231 9634 mobile kaylie.yankuraa-ncdenr.gov f-eeo --e - D, E Email correspondence to and from this address is subject to the North Carolina Public Records Law and may be disclosed to third parties Based on the current guidance to minimize the spread of COVID-19, the Department of Environmental Quality has adjusted operations to protect the health and safety of the staff and public. Many employees are working remotely or are on staggered shifts. To accommodate these staffing changes, all DEQ office locations are limiting public access to appointments only. Please check with the appropriate staff before visiting our offices, as we may be able to handle your requests by phone or email. We appreciate your patience as we continue to serve the public during this challenging time.