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Home My WebLink About202202064 Ver 1_Comment Response Letter 12-15-22 Kyle Barnes_20221219MEGINEERING Designing the Future... Today! December 15t", 2022 Kyle Barnes Regulatory Project Manager US Army Corps of Engineers RE: Choplin Farms Action ID SAW-2022-02064 This letter is written in response to the red -lines and comments dated December 15t", 2022, regarding the Stream and Wetlands Impact Application for Choplin Farms in Nash County, INC. A reply or explanation for each comment issued by your office is provided below and follows the original format of your memorandum. PCN Application Comments 1. Section C, 4i, of the PCN application: Please provide a detailed description of the impacts to jurisdictional Water and Wetlands that will be required as a result of this project. This should include enough detail to identify the reason for the calculation of impacts provided in Section D. We have added the following statement to Section C, 4i of the application for clarification. "The design features of our wetlands and jurisdictional water impacts include a road, a 72" diameter pipe, a 48" diameter pipe and a 4" diameter water utility line. These designed features will be permanent impacts on the wetlands and waters. Temporary impacts include a dam, sediment trap and stream crossing (Timber Mat)." 2. Establish a site review to confirm jurisdictional features on the property. Terracon has been contracted to submit the PJD and they will be in contact regarding the results. Design/Plan Set Concerns Culvert installation at the stream between Phase 1 and 2 (Street Q The culvert alignment does not connect to the stream geomorphic position. You must install a culvert to have an inlet/outlet in full connection of the impacted stream position and alignment. You have also designed a double barrel culvert with one of the barrels completely off line of the stream. Off line placement leads to erosion of the adjacent wetland and scour holes being formed. Please indicate why a larger single barrel culvert would not work in this situation. We had origin0y designed the culvert to be in a geomorphic position with the existing streambed. However, doing so would have placed the pipe in a position where the inv. out was placed almost perpendicular to the existing bank. We were worried that this would result in the discharge from the pipe blowing out the existing stream bank. We attempted to place the pipes in a position where they would be more in the flow path of the original stream and a blowout would not occur. To assist with erosion prevention, we have added a permanent Rip Rap Apron in our impact. Please see CE-14. The calculated flow for a 25-yr storm by NCDOT would require a 90" diameter pipe at this DocatOon. We do not have enough cover for a 90" pipe. Therefore, NCDOT gave us approval to use a combination of the 72" and 48" diameter pipes. The 72" pipe will carry the natural flow of the stream. The 48" has been set to activate during a 25-yr storm event. 2. The PCN application indicates the stream impact is 80 If x 7' width. The pictures of the stream provided in the application indicate that the stream width is roughly 7'. The plans indicate utilizing (2) 60" diameter culverts for the crossing of Street C. Please include information as to why there will be (2) culverts required for this crossing. The calculated flow for a 25-yr storm by NCDOT would require a 90" diameter pipe at this location. We do not have enough cover for a 90" pipe. Therefore, NCDOT gave us approval to use a combination of the 72" and 48" diameter pipes. The 72" pipe will carry the natural flow of the stream. The 48" has been set to activate during a 25-yr storm event. Please note the length of the permanent Rip Rap apron mentioned earlier is included in the stream impact length. 3. Plan page CE-14: Plan indicates the silt bag for the temporary pump around will be placed in the wetland. All measures associated with a pump around shall be placed outside of Waters and Wetlands except the intake hose. The silt bag and pump have been moved outside of the stream and wetland areas. Please see CE-14. 4. Provide a plan detail that indicates only impacts to jurisdictional waters and wetlands. The provided detail on CE-14 has too many layers to understand the impact area. Separate the Neuse Buffer impacts and the Waters and Wetlands impact details. Done, the Neuse buffer impacts, and the waters and wetlands impacts have been separated into (2) maps. Please see CE-14. 5. Temporary impacts: The project plans indicate temporary impacts associated with the pump around. The plans show a temporary dam and sediment trap. These impacts need to be quantified or indicated in the PCN. The temporary impacts have been quantifed and indicated. Please see CE-14 and the updated PCN form. 6. Does the quantified impacts include the length of the wing wall placement? Is there a concrete apron at the inlet and outlet of the culverts? If so this is an impact that needs to be included in the quantified impacts on the PCN. Yes, the quantified impacts include the wing wall placement. Please see CE-14. 7. Will the subdivision provide county sewer or will each lot require individual septic systems? I ask this because if individual septic systems are utilized there is potential for additional wetland fill request from individual landowners for lot development. The potential of secondary and cumulative impacts to waters and wetlands will need to be addressed in this permit action. This lots will have septic systems. The owner/developer has been instructed to not install septic tanks where the tank and the respective field would impact wetlands and or streams. The soils have been evaluated to provide septic field and repair areas outside all delineated wetlands and buffers. 8. How are utilities being installed from Phase 1 to Phase 2? Utility crossings of jurisdictional areas need to be quantified if clearing a corridor or open cut installation is utilized. Directional bore as long as nothing is staged in jurisdictional areas and no clearing is involved may not require permitting but that information should be included in the project narrative. There is a 4" diameter line crossing 8' off the edge of payment that falls within the street crossing impact evaluation area. The narrative has been updated to include the utilities line impact. If there are any further questions or concerns, please contact Stocks Engineering at 252.459.8196. Thanks! Sincerely, Stocks Engineering, P.A. Ethan Averette, PE.