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HomeMy WebLinkAbout20161220 Ver 2_I-5000 NCDOT Reponse to USACE AddInfo_20190916Please find below and attached NCDOT's responses to the questions sent on June 25, 2021. Multiple -part questions have been subdivided to ensure each element is addressed. 1. What work within jurisdictional areas are needed in order to complete the project as submitted? The remaining work includes: Site 3: The removal of Rankin Lake Road Bridge Site 1: The installation of the culvert sills, flood plain bench, and bank stabilization. When do you anticipate this work will be completed? August through October of this year. 2. Have all impacts already constructed within jurisdictional features been completed in accordance with the design authorized by the January 31, 2017 verification? With the exception of Sites 1 and 3 noted in question number 1, all impacts within jurisdictional features have been constructed and completed in accordance with the design authorized by the January 2017 verification. a. Was the Site 1 culvert extension elevation installed in accordance with plans? There has been previous discussion that the outlet elevation was potentially installed at a lower elevation which could increase the problem of sediment flushing downstream of this culvert. I have personally verified with NCDOT Hydraulics staff and NCDOT Construction staff that the culvert elevation was installed in accordance with the plans. b. Were benches and sills for Site 1 constructed in accordance with plans submitted with the original permit application The sills and benches have not yet been constructed. The purpose of the permit renewal/reissuance was to request the continuation of the construction of the project as previously permitted. The sills and benches will be constructed in accordance with the plans — Two 2-foot sills will be placed in two barrels and one barrel will not have a sill to facilitate base flow to flow through one barrel. and what is the current sediment depth sitting in the culvert (and over sills/benching if constructed)? The benches and sills at Site 1 have not yet been constructed. This incomplete activity is primary purpose for renewal/reissuance request. There is approximately 6 to 8 feet of sediment in the culvert. 3. There are some unanswered guestions regarding final design and function for the stream channel from the outlet of Site 1 thru the natural rock formation downstream of the bridge. a. Last update provided by NCDOT in 2019 indicated, based on modeling, that floodplain grading would help improve the attempts to lower sedimentation in this reach and provide a normal functioning channel dimension (with thalweg) as to the current wide, flat, sand bed channel present. Has the floodplain grading been completed to this design recommendation? If not, is it still the recommendation and when will it be completed? The floodplain grading has been completed, with the exception of the material to be removed when Rankin Lake Road bridge is removed. b. Were other recommendations made based on this model? Other recommendations were made and presented at the meeting. The meeting concluded with the determination to not create jurisdictional resource related impacts until the Rankin Lake Road bridge was removed. c. What is the timeline for the removal of the Rankin Lake Road bridge August through October 2021. and is the man-made cascade immediately downstream of the bridge also to be removed? As previously permitted, this feature will also be removed at the same time as the Rankin Lake Road bridge. If not, is the elevation of the cascade causing increased sediment elevations in this area or the Site 1 culvert? d. What extent is the combination of the floodplain grading and the Rankin Lake Road bridge removal expected to lower the sediment elevation in this reach of stream and how much sediment is anticipated to stay within the culvert? The combination of the floodplain grading and the Rankin Lake Road bridge removal will increase the velocity of the water within the stream and culverts to a magnitude sufficient for the movement of accumulated sediment and the sustained movement of suspended sediment downstream. The exact amount of sediment that will remain in the culvert in the longer term (1 year out, and beyond) will be difficult to predict due to site conditions, modeling limitations and storm events that the culvert will experience. e. In my April 1, 2019 information request email, during our August 22, 2019 project meeting and in my September 16, 2019 information request email I asked for clarification as to whether the Site 1 benching/sills will be functioning as designed and agreed upon during pre -application meetings based on channel sedimentation (base flow in one barrel in order to provide more appropriate dimension). It is still not clear to me if the sediment elevation within this stream reach and culvert Site 1 will be above bench and sill height based on the presence of natural rock downstream of Site 1. The sill height in the low flow barrel will be 688.5' and 690.5' in the high flow barrel. We anticipate sediment will be at the elevation of the downstream rock or higher as sediment forms a natural gradient from the culvert outlet to the rock formation. i. Are bedrock formations downstream of Site 1 going to hold sediment elevations higher than the existing culvert outlet elevation? What height? The elevation of the rock line is approximately 690', while the proposed culvert invert elevation in the low flow barrel will be 688.5' (690.5' in the high flow). Some movement of sediment will be expected from within the culvert once higher velocities are reached upon the completion of the floodplain grading and the removal of Rankin Lake Rd bridge. ii. Are any bedrock formations proposed for removal at this time in order to flush sediment? Will they be accessible if further work is needed on them later? No additional work is proposed other than what has previously been permitted for this project. If the USACE and NCDWR request the removal of bedrock formations to achieve environmental compliance, access to the stream could be achieved from the east. iii. Is NCDOT recommending design changes to the bench or sill elevations at Site 1 in order to maintain baseflow through a singe barrel of the triple barrel culvert? NCDOT is not recommending design changes at this time, other than the floodplain grading that has already occurred. After the remaining work is complete, (Rankin Lake Road bridge is removed, sills and benches are installed), if additional work is required to bring the stream into environmental compliance, the environmental agencies, NCDOT hydraulic staff, and hydraulic studies (modeling) will determine the best course of action to achieve a stream that maintains its natural baseflow though the project impacted area. iv. Is there any reason why NCDOT believes base flow through a single barrel is incorrect for reaching appropriate channel dimension or not attainable at this point? NCDOT continues to believe the base flow through a single barrel is correct for reaching appropriate channel dimension. Once the sediment accumulated in the culvert has migrated further downstream, the base flow should be in only one barrel. v. Will Site 1 meet permit conditions GP50 Special Condition 1(d) Culverts and Pipes. If not, please explain why and what design NCDOT believes to be appropriate. NCDOT believes Site 1 will meet the GP50 Special Condition 1(d) once the remaining work is complete, (Rankin Lake Road Bridge and culvert sills installed). This is special condition 1(d): d. Culverts and pipes. The following conditions [(1)-(8)] apply to the construction of culverts/pipes, and work on existing culverts/pipes. Additionally, if the proposed work would affect an existing culvert/pipe (e.g., culvert/pipe extensions), the prospective permittee must include actions (in the PCN) to correct any existing deficiencies that are located: • At the inlet and/or outlet of the existing culvert/pipe, IF these deficiencies are/were caused by the existing culvert/pipe, or • Near the inlet or outlet of the existing culvert/pipe, IF these deficiencies are/were caused by the existing culvert/pipe. These deficiencies may include, but are not limited to, stream over -widening, bank erosion, streambed scour, perched culvert/pipes, and inadequate water depth in culvert(s). Also note if the proposed work would address the existing deficiency or eliminate it — e.g., bank erosion on left bank, but the culvert extension will be placed in this eroded area. If the prospective permittee is unable to correct the deficiencies caused by the existing culvert/pipe, they must document the reasons in the PCN for Corps consideration. (1) No activity may result in substantial, permanent disruption of the movement of those species of aquatic life indigenous to the waterbody, including those species that normally migrate through the area. Measures will be included that will promote the safe passage of fish and other aquatic organisms. (2) The dimension, pattern, and profile of the stream above and below a culvert/pipe shall not be modified by widening the stream channel or by reducing the depth of the stream in connection with the construction activity. It is acceptable to use rock vanes at culvert/pipe outlets to ensure, enhance, or maintain aquatic passage. Pre -formed scour holes are acceptable when designed for velocity reduction. The width, height, and gradient of a proposed opening shall be such as to pass the average historical low flow and spring flow without adversely altering flow velocity. Spring flow will be determined from gauge data, if available. In the absence of such data, bankfull flow will be used as a comparable level. (3) Burial/depth specifications: If the project is located within any of the 20* CAMA counties, culvert/pipe inverts will be buried at least one foot below normal bed elevation when they are placed within the Public Trust AEC and/or the Estuarine Waters AEC as designated by CAMA. If the project is located outside of the 20* CAMA counties, culvert/pipe inverts will be buried at least one foot below the bed of the stream for culverts/pipes that are greater than 48 inches in diameter. Culverts/pipes that are 48 inches in diameter or less shall be buried or placed on the stream bed as practicable and appropriate to maintain aquatic passage, to include passage during drought or low flow conditions. Every effort shall be made to maintain the existing channel slope. A waiver from the burial/depth specifications in this condition may be requested in writing. The prospective permittee is encouraged to request agency input about waiver requests as early as possible, and prior to submitting the PCN for a specific project; this will allow the agencies time to conduct a site visit, if necessary, and will prevent time delays and potential project revisions for the prospective permittee. The waiver will only be issued by the Corps if it can be demonstrated that the impacts of complying with burial requirements would result in more adverse impacts to the aquatic environment. (4) Appropriate actions to prevent destabilization of the channel and head cutting upstream shall be incorporated in the design and placement of culverts/pipes. (5) Culverts/pipes placed within riparian and/or riverine wetlands must be installed in a manner that does not restrict the flow and circulation patterns of waters of the U.S. Culverts/pipes placed across wetland fills purely for the purposes of equalizing surface 6 water do not have to be buried, but must be of adequate size and/or number to ensure unrestricted transmission of water. (6) Bankfull flows (or less) shall be accommodated through maintenance of the existing bankfull channel cross sectional area in no more than one culvert/pipe or culvert/pipe barrel. Additional culverts/pipes or barrels at such crossings shall be allowed only to receive flows exceeding the bankfull flow. A waiver from this condition may be requested in writing; this request must be specific as to the reason(s) for the request. The waiver will be issued if it can be demonstrated that it is not practicable to comply with this condition. (7) Where adjacent floodplain is available, flows exceeding bankfull will be accommodated by installing culverts/pipes at the floodplain elevation. When multiple culverts/pipes are used, baseflow must be maintained at the appropriate width and depth by the construction of floodplain benches, sills, and/or construction methods to ensure that the overflow culvert(s)/pipe(s) is elevated above the baseflow culvert(s)/pipe(s). (8) The width of the baseflow culvert/pipe shall be comparable to the width of the bankfull width of the stream channel. If the width of the baseflow culvert/pipe is wider than the stream channel, the culvert/pipe shall include baffles, benches and/or sills to maintain the width of the stream channel. A waiver from this condition may be requested in writing; this request must be specific as to the reason(s) for the request. The waiver will be issued if it can be demonstrated that it is not practicable or necessary to include baffles, benches or sills. 4. The initial permit verification included monitoring requirements to ensure that the Site 1 thru Rankin Lake Road bridge project reach is constructed to meet agency expectations and permit conditions. Monitoring conditions will be required in the permit re -issuance and if this reach does not adjust appropriately, additional actions may be required. a. Have any initial monitoring steps already been set up (cross sections, photo stations, bank pins, etc.)? As construction is not complete in this area, (as the Rankin Lake Road Bridge has not yet been removed, and culvert sills have not yet been installed), the monitoring phase of the project has not started. b. What monitoring and timeline does NCDOT propose in order to adequately ensure that channel conditions meet agency requirements? NCDOT intends to execute the previous permit condition #2 indicating: Special Condition #2 / 404 USACE Permit: The stream channel (Highland Creek) within the project area between the 1-85 culvert extension (Site 1) and the rock check damn downstream of the Rankin Lake Road Bridge (Site 3) shall be visually monitored with photo stations for at least two bankfull flow events occurring in separate calendar years to ensure channel stability post construction. c. Who is proposed to complete monitoring in this project reach (Div12, Central Office, consultant, etc.)? NCDOT Environmental Analysis Unit will complete the monitoring. Additional assistance/ surveys/ recommendations may be consulted from NCDOT Hydraulics Unit and may involve consultants in modeling efforts. 5. Has all compensatory mitigation been paid in accordance with Special Condition 1 and the Mitigation Responsibility Transfer Form accompanying your January 31, 2017 permit verification? Please provide a copy of the MRTF signed my DMS. All compensatory mitigation has been paid in accordance with Special Condition 1 and the Mitigation Responsibility Transfer Form (MRTF). A signed copy of the MRTF is attached with this response. 6. At Site 6, the 3-sided culvert (Conspan) installed under Bulb Avenue, no permanent impacts within the Conspan were proposed or authorized based on initial project design. After discovering a bedrock stream in this location and the pre -constructed Conspan to be too narrow to entirely avoid the stream, some impacts seemed likely to occur in this project location. Provide a brief description of impacts that occurred and an estimate (linear footage) of permanent impacts within the Ordinary High Water Mark of the stream associated with this culvert. Pictures of the inside of the completed culvert would be hejpful if available. During construction of bottomless structures, it is often necessary to remove a layer of non -supporting bedrock so that the structure rests evenly on solid material. This level of work varies with each rock foundation, and with each stream. On this project, foundation work resulted in the edges of the stream to be impacted at alternating locations throughout the culvert. Although the stream continues to flow on its natural stream bottom, these final impacts are most categorized as bank stabilization, as the stream edge is armored at these locations to ensure a stable bank/edge. If the agencies determine this impact better aligns with classification of permanent bank stabilization, the culvert length (164 If) should be used. Recent photos have been requested and will be provided as soon as they are received. U.S. ARMY CORPS OF ENGINEERS Wilmington District Compensatory Mitigation Responsibility Transfer Form Permittee: NCDOT/ Attn: Philip Harris Action ID: SAW-2010-00033 Project Name: NCDOT-US321I85Interchange-I5000-Gaston-Div12 County: Gaston Instructions to Permittee: The Permittee must provide a copy of this form to the Mitigation Sponsor, either an approved Mitigation Bank or the North Carolina Division of Mitigation Services (NCDMS), who will then sign the form to verify the transfer of the mitigation responsibility. Once the Sponsor has signed this form, it is the Permittee's responsibility to ensure that to the U.S. Army Corps of Engineers (USACE) Project Manager identified on page two is in receipt of a signed copy of this form before conducting authorized impacts, unless otherwise specified below. If more than one mitigation Sponsor will be used to provide the mitigation associated with the permit, or if the impacts and/or the mitigation will occur in more than one 8-digit Hydrologic Unit Code (HUC), multiple forms will be attached to the permit, and the separate forms for each Sponsor and/or HUC must be provided to the appropriate mitigation Sponsors. Instructions to Sponsor: The Sponsor must verify that the mitigation requirements (credits) shown below are available at the identified site. By signing below, the Sponsor is accepting full responsibility for the identified mitigation, regardless of whether or not they have received payment from the Permittee. Once the form is signed, the Sponsor must update the bank ledger and provide a copy of the signed form and the updated bank ledger to the Permittee, the USACE Project Manager, and the Wilmington District Mitigation Office (see contact information on page 2). The Sponsor must also comply with all reporting requirements established in their authorizing instrument. Permitted Impacts and Compensatory Mitigation Requirements: Permitted Impacts Requiring Mitigation* 8-digit HUC and Basi Stream Impacts (linear feet) Wetland Impacts (acres) Warm Cool Cold Riparian Riverine Riparian Non-Riverine Non -Riparian Coastal 197 0.09 more than one mitigation sponsor will be used for the permit, only include impacts to be mitigated by this sponsor. Compensatory Mitigation Requirements: 8-digit HUC and Basin: Stream Mitigation (credits) Wetland Mitigation (credits) Warm Cool Cold Riparian Riverine Riparian Non-Riverine Non -Riparian Coastal 394 0.18 Mitigation Site Debited: NCDMS (List the name of the bank to be debited. For umbrella banks, also list the specific site. For NCDMS, list NCDMS. If the NCDMS acceptance letter identifies a specific site, also list the specific site to be debited). Section to be completed by the Mitigation Sponsor Statement of Mitigation Liability Acceptance: I, the undersigned, verify that I am authorized to approve mitigation transactions for the Mitigation Sponsor shown below, and I certify that the Sponsor agrees to accept full responsibility for providing the mitigation identified in this document (see the table above), associated with the USACE Permittee and Action ID number shown. I also verify that released credits (and/or advance credits for NCDMS), as approved by the USACE, are currently available at the mitigation site identified above. Further, I understand that if the Sponsor fails to provide the required compensatory mitigation, the USACE Wilmington District Engineer may pursue measures against the Sponsor to ensure compliance associated with the mitigation requirements. Mitigation Sponsor Name: MC_Ot cl JM S Name of S . • nsor's Authorized Representative: I+k) cliotorr ) ancY) CE40 fL7 Signature of Sponsor's Authorized Representative Date of Signature Page 1 of 2 Form Updated 12 September, 2014 USACE Wilmington District Compensatory Mitigation Responsibility Transfer Form, Page 2 Conditions for Transfer of Compensatory Mitigation Credit: • Once this document has been signed by the Mitigation Sponsor and the USACE is in receipt of the signed form, the Permittee is no longer responsible for providing the mitigation identified in this form, though the Permittee remains responsible for any other mitigation requirements stated in the permit conditions. • Construction within jurisdictional areas authorized by the permit identified on page one of this form can begin only after the USACE is in receipt of a copy of this document signed by the Sponsor, confirming that the Sponsor has accepted responsibility for providing the mitigation requirements listed herein. For authorized impacts conducted by the North Carolina Department of Transportation (NCDOT), construction within jurisdictional areas may proceed upon permit issuance; however, a copy of this form signed by the Sponsor must be provided to the USACE within 30 days of permit issuance. NCDOT remains fully responsible for the mitigation until the USACE has received this form, confirming that the Sponsor has accepted responsibility for providing the mitigation requirements listed herein. • Signed copies of this document must be retained by the Permittee, Mitigation Sponsor, and in the USACE administrative records for both the permit and the Bank/ILF Instrument. It is the Permittee's responsibility to ensure that the USACE Project Manager (address below) is provided with a signed copy of this form. • If changes are proposed to the type, amount, or location of mitigation after this form has been signed and returned to the USACE, the Sponsor must obtain case -by -case approval from the USACE Project Manager and/or North Carolina Interagency Review Team (NCIRT). If approved, higher mitigation ratios may be applied, as per current District guidance and a new version of this form must be completed and included in the USACE administrative records for both the permit and the Bank/ILF Instrument. Comments/Additional Conditions: This form is not valid unless signed below by the USACE Project Manager and by the Mitigation Sponsor on Page 1. Once signed, the Sponsor should provide copies of this form along with an updated bank ledger to: 1) the Permittee, 2) the USACE Project Manager at the address below, and 3) the Wilmington District Mitigation Office, Attn: Todd Tugwell, 11405 Falls of Neuse Road, Wake Forest, NC27587 (email: todd.tugwell@usace.army.mil). Questions regarding this form or any of the permit conditions may be directed to the USACE Project Manager below. USACE Project Manager: USACE Field Office: Email: Steve Kichefski Asheville Regulatory Field Office US Army Corps of Engineers 151 Patton Avenue, Room 208 Asheville, North Carolina 28801-5006 steven.l.kichefski@usace.army.mil KI C H E F S KI . ST EV E N N. L. Digitally signed by KICHEFSKI.STEVEN.L.1386908539 DN: c=US, o=U.S. Government, ou=DoD, ou=PKI, ou=USA, 1386908539 Date: 2017.013116:38:38 05E00L.1386908539 January3l, 2017 USACE Project Manager Signature Date of Signature Current Wilmington District mitigation guidance, including information on mitigation ratios, functional assessments, and mitigation bank location and availability, and credit classifications (including stream temperature and wetland groupings) is available at http://ribits.usace.army.mil. Page 2 of 2 The Wilmington District is committed to providing the highest level of support to the public. To help us ensure we continue to do so, please complete the Customer Satisfaction Survey located at our website at http://regulatory.usacesurvev.com/ to complete the survey online.