Loading...
HomeMy WebLinkAboutOregon Inlet Q4 2023 Maintenance Event Request DCMCOASTAL PROTECTION ENGINEERING OF NORTH CAROLINA, INC 4038 MASONBORo Loop ROAD COASTAL WILMINGTON, NC 28409 PROTECTION 910-399-1905 ENRINEERINR 00 September 19, 2023 Heather Coats Beach & Inlet Management Project Coordinator North Carolina Division of Coastal Management 127 Cardinal Drive Wilmington, NC 28405 Subject: Oregon Inlet Channel Maintenance Project — Written Notice of Intent to Conduct Maintenance Dredging in Q4 of 2023 (Major Permit #49-19) Dear Ms. Coats: The Division of Coastal Management (DCM) issued a CAMA Major Permit (#49-19) for the maintenance of Oregon Inlet on June 24, 2019. This permit was subsequently modified on December 21, 2021 and has a current expiration date of December 31, 2024. This letter serves as a written notice of Dare County's intent to initiate dredging under the subject permit. Dare County intends to utilize the dredge Miss Katie to maintain the Ocean Bar Channel at Oregon Inlet, portions of the channel that nun from Oregon Inlet to Hells Gate referred to as the Alternate Route, and portions of Old House Channel Range 1. Dredged material will be placed in proximity to the remaining portion of the Bonner Bridge and in the nearshore disposal area offshore Pea Island, in accordance with the pennits. As previously coordinated with your office, dredging has been conducted in the Ocean Bar Channel since August 2022 and in the portion of the Oregon Inlet to Hells Gate channel refereed to as the Alternate Route since October 2022. Dredging is scheduled to continue as needed from October 1 through December 31 2023. Given the frequent need for maintenance dredging at Oregon Inlet, Dare County anticipates the Miss Katie will perform regular maintenance work under the subject pennit for the foreseeable future. However, this correspondence is specifically noticing for dredge operations anticipated to occur in Q4 of 2023 (October through December. The forthcoming dredge maintenance event is anticipated to be limited to dredging within the portions of the Oregon Inlet Ocean Bar Channel, the Oregon Inlet to Hells Gate Channel (Alternate Route, and Old House Channel Range 1 as shown on the attached plans dated September 19 2023. Dredging of the Ocean Bar Channel will follow best water as determined through coordination with the USACE Wilmington District Navigation Branch. Dredging will be limited to a 400-foot-wide channel with bottom elevation of -16 ft. MLLW. Dredging of the Oregon Inlet to Hells Gate Channel (Alternate Route) will be limited to the specific footprint shown on the attached plans to comply with requirements of the Dept. of Army pernit. Dredging in this channel will be limited to a 100-foot-wide channel with bottom elevation of -10 ft. MLLW. Dredging of the Old House Channel Range 1 Channel will be limited to the specific footprint shown on the attached plans, which includes a 100-foot-wide channel with bottom elevation of -12 ft. MLLW. The disposal sites permitted include a nearshore disposal site located off the northeastern end of Pea Island and disposal in proximity to the deep scour holes beneath the Herbert C. Bonner Bridge. On June 26 2023, Dare County requested a modification to CAMA Permit #49-19 to allow Miss Katie to place material as deep as -17 ft MLLW within the nearshore disposal site off Pea Island and expand the extent of the disposal area an additional 5,000 feet. At this time, the permit modification has yet to be issued. Because the majority of the existing Bonner Bridge has been demolished, the County's permit limits the disposal to the areas surrounding the remaining bridge pilings which extend from the shoulder of Pea Island approximately 1,500 feet. This remaining portion of the bridge is known as the "training structure". The training structure has been left in place to help keep the inlet navigable after removal of the majority of the old bridge. The intention for keeping the training structure in place is to forestall Davis Slough from returning to the prevailing deep -water channel through which it flowed prior to the construction of the old bridge. The presence of the training structure, therefore, effectively serves to minimize the risk that the deep -water channel will migrate south and threaten the integrity of the Pea Island terminal groin. Based on the latest bathymetric surveys conducted for the Ocean Bar Channel by the USACE Wilmington District Navigation Branch on August 8, 2023, the estimated volume of material required to be removed to achieve the design channel dimensions for the proposed channel is approximately 26,800 cubic yards. Based on bathymetric surveys conducted by the USACE Wilmington District Navigation Branch on August 1, 2023, the estimated volume of material required to be removed to achieve the design channel dimensions for the proposed Oregon Inlet to Hells Gate Channel (Alternate Route) is approximately 14,400 cubic yards. Based on bathymetric surveys conducted by the USACE Wilmington District Navigation Branch on August 1, 2023, the estimated volume of material required to be removed to achieve the design channel dimensions for Old House Channel Range 1 is approximately 7,000 cubic yards. Permit Condition #5 of the CAMA Major Permit states, "Prior to the initiation of any dredgng a tivties autbori.�ed by this permit, the permittee shall, in coordination witb the N.C. Department of Natural and Cultural Resources (DNCR), demlop and implement an arcbaeological survey of the proposed proyict area. Initiation of permitted dredging a tiv fies shall not be until written approval is obtained from DNCR, and a copy of such aj prowl bas been submitted to the Division of Coastal Management " In a letter dated August 15, 2022, DNCR stated that with the present alignment of the Ocean Bar Channel the dredging project will avoid the assumed coordinates of the potentially National Register of Historic Places (NRHP) eligible shipwreck W.G. Townsend. Through further coordination, a 100-foot radius buffer has been established around the coordinates of the W.G. Townsend to avoid any impacts. In a letter dated July 29, 2022, DNCR concurred to the USACE Wilmington Districts request for emergency dredging within the specific footprint of the "Western Alternate Route", which is the channel referred to in the attached plans as Hells Gate to Oregon Inlet (Alternate Route). Based on this previous coordination with the DNCR for Q3-2022, the fact that the channel location of both the Ocean Bar Channel and the Alternate Route are the some as proposed for Q3-2022, and the fact that Old House Channel Range 1 is a fixed location that has previously been dredged by the USACE, Dare County and its consultants are of the opinion that CAMA Major Permit Condition #5 has been satisfied. In accordance with Permit Condition #7, Dare County worked with the USACE regulatory project manager and EJE Dredging to confirm the dredge has been constructed in accordance with the USACE hopper dredge plant specifications and that the dredge plant complies with the conditions of the Corps' 2004 FONSI. The inspections were signed off on by the County, EJE Dredging, and Josh Pelletier on August 26, 2022. A pre -construction conference has been scheduled for September 25, 2023 at 1:30 pm in accordance with Condition #10. Please feel free to contact me anytime for further clarification or explanation of the project. Very truly yours, COASTAL PROTECTION ENGINEERING OF NORTH CAROLINA, INC. Ken Willson Project Manager CC: Robert Outten, Daze County Barton Grover, Daze County Gregg Bodnar, NC DCM Josh Pelletier, USACE Washington, NC Regulatory Office Robert Tankard, NC DWR Sabrina Henry, NPS