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HomeMy WebLinkAboutDuck Application NarrativeApplication for Major Development Permit Town of Duck Shore Protection Project C OASTA L P ROTECTION E NGI NEERI NG OF N ORTH C A RO LINA , I NC . 10 2 Supplemental Information, per Forms DCM MP-1 and DCM MP-2 2.1 Per Form MP-1, Section 6a: Project Narrative 2.1.1 Project Scoping and History The Town of Duck is one of four towns within Dare County, including Southern Shores, Kitty Hawk, and Kill Devil Hills seeking to implement simultaneous shore protection projects to help mitigate the threat of long-term erosion and storm damage which pose a continual threat to the oceanfront shoreline. The first of these four towns to express interest in obtaining permits and implement a shore protection project was the Town of Kill Devil Hills which, along with the Town of Kitty Hawk, was originally part of a federally authorized beach nourishment project within Dare County. However, due to shortfalls in federal funding, the project was never constructed and is not anticipated in the foreseeable future. Therefore, on September 14, 2011, the Town of Kill Devil Hills held an interagency scoping meeting in Washington, NC with representatives from various state and federal agencies including the North Carolina Division of Coastal Management (DCM), North Carolina Wildlife Resources Commission (NCWRC), United State Army Corps of Engineers (USACE), US Fish and Wildlife Service (USFWS) and National Marine Fisheries Service (NMFS). The purpose of the meeting was to present the scope of a proposed locally sponsored shoreline protection project and to develop an agreed upon permitting approach and scope for the required environmental documentation. One outcome of the meeting was the decision to develop a “Project Information Document” that would provide the USACE with a summary of the relevant existing environmental documentation and biological data that pertains to the proposed Kill Devil Hills Shore Protection Project. The information provided within the document was to be used to assist the USACE in determining the appropriate environmental documenting requirements. Following the submittal of the document, the USACE responded that due to the likelihood of determining a Finding of No Significant Impacts (FONSI), an Environmental Assessment (EA) would be the recommended approach regarding the required environmental documentation. Following the 2011 interagency meeting, two other beach towns in Dare County (Kitty Hawk and Duck) expressed interest in pursuing their own shoreline protection projects in light of continued erosion on their respective shorelines. Considering that all three towns were proceeding with similar nourishment projects, constructing these projects within the same year, either concurrently or sequentially, would reduce mobilization costs to the towns. Subsequently, an additional interagency meeting was held on June 19, 2013 with representatives from many of the same agencies to discuss proposed permitting and environmental documentation approaches for all three towns, (Kill Devil Hills, Kitty Hawk, and Duck). During the meeting it was determined that each town should apply for their own set of permits and develop their own separate EAs. However, representatives from the U.S. Fish and Wildlife Service (USFWS) and the National Marine Fisheries Service (NMFS) agreed that while individual EAs could be drafted for each of the three proposed projects, a single regional EFH assessment and a single batched Biological Assessment (BA) could be submitted to satisfy consultation requirements with NMFS and USFWS (i.e., under the Magnuson-Stevens Act and Endangered Species Act, respectively) for the Towns of Duck, Kitty Hawk, and Kill Devil Hills. Because the project involved the use of OCS borrow areas, which fall under the Bureau of Ocean Energy Management (BOEM) jurisdiction, and placement of material on the beach, which falls under the USACE’s jurisdiction, it was determined that BOEM and the USACE would act as joint-lead agencies for NEPA purposes and would prepare joint NEPA documents. BOEM and the USACE agreed to participate in the required Endangered Species Act (ESA) Section 7 consultations; the Magnuson-Stevens Fishery and Conservation Management Act Essential Fish Habitat (EFH) consultation (Section 305); the National Historic Preservation Act Application for Major Development Permit Town of Duck Shore Protection Project C OASTA L P ROTECTION E NGI NEERI NG OF N ORTH C A RO LINA , I NC . 11 Section (NHPA) Section 106 process; and the Coastal Zone Management Act (CZMA) Section 307 consistency process. In a letter from BOEM to the USACE dated December 2, 2014, the environmental documentation and permitting approach as described above was codified. It stated that lead agency in Endangered Species Act (ESA) Section 7 consultation for potential impacts on protected species would be determined by jurisdiction. The BOEM was determined to be the lead agency and would consult with NMFS concerning potential effects from dredging activities for species under their purview (i.e. swimming turtles and whales). The USACE was determined to be the lead agency and consult with UFWS concerning effects from placement activities for species under their purview (i.e. nesting sea turtles). BOEM and the USACE consulted jointly with NMFS Habitat Conservation Division on EFH and requested NMFS to assign conservation recommendations by jurisdiction. The USACE was the lead agency for the National Historic Preservation Act (NHPA) Section 106 and notified the State Historic Preservation Office (SHPO) and relevant Tribal Historic Preservation Offices (THPO). The USACE and BOEM worked together with the North Carolina Department of Environmental and Natural Resources (NCDENR), to ensure compliance with Section 307 of the Coastal Zone Management Act (CZMA). Following the submittal of the three EAs, Department of Army (DA) Individual Permits were issued to each of the three towns for the 2017 beach nourishment event (SAW-2014-02202, SAW-2014-02203, and SAW-2014- 02204). Consultations with NMFS Protected Resource Division concluded with the issuance of Biological Opinion on May 16, 2016. Consultations with USFWS concluded with the issuance of a Biological Opinion on November 4, 2015, respectively. Consultation with NMFS Habitat Conservation Division in regard to EFH concerns resulted in a "no staffing" email with one recommendation. DCM issued Major Permits to each town as well (Town of Duck, #132-15; Town of Kitty Hawk, #133-15; and Town of Kill Devil Hills, #134-15). An additional interagency scoping meeting convened on January 31, 2017 to discuss the Town of Southern Shores' desire to place beach fill material within a limited area of the Town's oceanfront shoreline. Due to the project's proximity to Kitty Hawk and their intention to construct the project in tandem with the other three beach town projects, regulatory agencies determined the applicant should apply for their own separate CAMA Major permit and modify Kitty Hawk's existing DA Individual permit. During consultation with the federal partners, the batched BA was also amended to include Southern Shore's project-specific information. DCM subsequently issued a CAMA Major Permit #59-17 to the Town of Southern Shores while the DA issued a modification of the Town of Kitty Hawk's Individual Permit SAW-2014-02204. In 2017, the four towns cost-shared and implemented a beach nourishment project that involved the placement of approximately 3.9 million (M) cubic yards of material over nearly 8.3 miles of oceanfront shoreline. Material used for the project was obtained from two offshore borrow areas within the Outer Continental Shelf (OCS) in federal waters. Great Lakes Dredge and Dock performed the dredging work in 153 days using three (3) hopper dredges; the Liberty Island, Dodge Island and Padre Island. Dredging began on May 23, 2017, placing material at the Town of Duck and was concluded on October 23, 2017 with nourishment at the Town of Kitty Hawk. The beach fill design for the 2017 project at the Town of Duck included a 20-foot-wide dune at elevation +20.0 feet NAVD fronted by a variable width berm at elevation +6.0 feet NAVD. A main fill section was constructed covering 7,915 feet of shoreline beginning on the north at profile station D-10, which is located near 140 Skimmer Way, and ending on the south near station D-19 which is located at the south property line of 137 Spindrift Lane. A five hundred (500) foot taper was construction on the north end of the fill to provide a gradual merger of the project shoreline with the existing shoreline. Collectively, 1,263,181 cubic yards of material was placed within this domain using material obtained from Borrow Area A and Borrow Area C. Due to concerns with possible damage to sensitive instruments buried on its property, the USACE Field Research Facility requested no material be deposited directly along its shoreline. As a result, a taper was not provided at the south end of the project, Application for Major Development Permit Town of Duck Shore Protection Project C OASTA L P ROTECTION E NGI NEERI NG OF N ORTH C A RO LINA , I NC . 12 rather, the volume of material originally included in the south taper was distributed along the southern extends of the main fill. After the completion of the 2017 nourishment event and based on interest expressed by all four beach towns to pursue an additional nourishment event in the future, an interagency meeting convened on April 29, 2020 to discuss the permitting and environmental documentation approach that would be required for the future project. During the meeting, it was decided that each town would pursue their own respective set of permits. In order to satisfy NEPA documentation requirements, however, it was decided that one collective EA would be developed and would be inclusive of site-specific information for all four beach towns. It was also determined that the project-related actions, as presented during the scoping meeting, should be covered by the 2020 South Atlantic Regional Opinion (SARBO) and the 2017 North Carolina Coastal Beach Sand Placement Statewide Programmatic Biological Opinion. As such, the issuance of a new biological opinion as part of the federal consultation process with NMFS and USFWS are not anticipated. The April 29, 2020 scoping meeting was attended by representatives of the Division of Water Resources (DWR) and met the requirement for requesting a pre-filing meeting under 40 CFR Part 121 for 401 Certifications in accordance with the federal Clean Water Act. The project proponent hereby certifies that all information contained herein is true, accurate, and complete to the best of my knowledge and belief. The project proponent hereby requests that the certifying authority review and take action on this CWA 401 certification request within the applicable reasonable period of time. 2.1.2 Proposed Action The proposed action is a one-time beach nourishment event that will include sand placement along a 1.6-mile section of the Town’s oceanfront shoreline using dredged material from within Borrow Area A. The proposed design consists of a 20-foot wide dune at elevation +20 feet NAVD88, with a seaward slope of 1V:5H, fronted by a variable width berm at elevation +6 feet NAVD88. The main placement area begins near the northern property boundary of 140 Skimmer Way and extends approximately 7,914 feet southward, terminating in the middle of the parcel at 137 Spindrift Lane. Additionally, there is one 500-foot taper on the north end of the main fill, that extends from the northern boundary of the main placement to the property line between 126 and 128 Skimmer Way. The total linear extent of sand placement is approximately 8,414.7 feet (1.6 miles). Plan views and cross sections of the design template are shown in Appendix A, sheets 1 through 10. Each cross-section corresponds with profiles with approximately 1,000-foot spacing. The total fill area below MHW is 3,023,609 square feet (69.41 acres), and the total fill area above MHW is 1,488,346 square feet (34.17 acres), for a total disturbed area of 4,511955 square feet (103.58 acres). Construction of the preferred design along with 5 years of advanced fill would require 806,500 cubic yards of fill material obtained from Borrow Area A. Actual volume dredged from the borrow area will likely require up to an additional 20% to account for losses during dredging; therefore, the total estimated dredge volume is 967,800 cubic yards. The BOEM lease request for excavating material from within Borrow Area A will include additional volume in the unlikely event a storm eroded the Towns' shoreline prior to the construction of the project. In total, the amount of material that could be excavated from the borrow area would be 1,209,750 cy, or 50% more than the 806,500 cy of fill required by the preferred design and advanced fill. Following the construction of the 2017 project, an after-dredge survey revealed that Borrow Area A still contained 12,829,500 cy of material, therefore this borrow area contains enough volume for this project along with the other three towns' proposed projects. Material will be obtained from the borrow area using a hopper dredge, a cutterhead dredge, or a combination of the two. In the case of a cutterhead dredge, sand will be transported from the borrow area to the beach as a slurry via pipeline; use of a hopper dredge would involve transport to a nearshore pump-out location, and subsequent pumping to the beach via pipeline. A sand dike will be constructed on the seaward side of the discharge area. The Application for Major Development Permit Town of Duck Shore Protection Project C OASTA L P ROTECTION E NGI NEERI NG OF N ORTH C A RO LINA , I NC . 13 sand slurry will be discharged behind the temporary dike, and excess water will be directed parallel to the shoreline and around the edge of the dike. Once discharged onto the beach, the material will be shaped and graded using loaders, dozers, and other earth moving equipment. There are six proposed staging areas for this project. Two are located south of the project limits; one at Barrier Island Station and one at the USACE Field Research Facility (FRF) (Appendix A, sheets 3 and 4). The FRF staging areaconsists of an existing paved (impervious) lot encompassing approximately 0.28 acres, and an associated dirt road would be used as a 1,060 linear feet construction access to the beach. Two other staging areas are located along Trinitie Drive and Duck Rd (Appendix A, sheet 6). The two staging areas on or in proximity to Trinitie Drive encompass approximately 0.06 and 0.08 acres, respectively. The construction access to the beach measures 286 feet. The staging area along Sound Sea Ave is approximately 0.27 acres with its construction access to the beach measuring approximately 352 linear feet (Appendix A, sheet 7). The last staging area, located on Acorn Oak Ave. The staging area on Acorn Oak Ave. encompasses 0.16 acres with a construction corridor measuring 3018 feet (Appendix A, sheet 7). Collectively, these five staging areas encompass a total of 0.85 acres. An additional construction access to the beach spanning 158 feet is also included at Station Bay Drive (Appendix A, sheet 8). No impervious surfaces or alterations to the dunes will be required for use of these areas. The Town installed multiple rows of sand fencing and planted extensive dune vegetation along the constructed dune following the 2017 nourishment event to trap windblown sand and encourage dune growth. For the most part, the proposed project will not include the construction of additional dunes with the exceptions of those areas of the project where portions of the designed dune have been lost since the 2017 event. In these areas, the Town will install sand fencing along the portions of the dune that were re-constructed in accordance with either 15A NCAC 07K .0212 or 15A NAC 07H .0311(c). If sand fencing is to be installed under 15A NAC 07H .0311(c), the Town request a minor modification to allow for the installation of along the face of the constructed dune and will agree to complete the installation within these areas after October 31. The Town established a dune vegetation program following construction of the 2017 project. The initial dune vegetation program included planting of American Beach Grass and Sea Oats, and Bitter Panicum. A similar dune vegetation plan will be implemented for this proposed project. A number of measures will be employed to avoid or minimize the risk to biological and natural resources within the project area. These measures are described in Table 1. below. Table 1. Conservation/Monitoring measures implemented to avoid or minimize environmental risks Conservation/Monitoring Measure Borrow Area Design The size and shape of the borrow areas have been designed such that a minimum number of turns will be required by the hopper dredge, which increases dredge efficiency and reduces the potential for sea turtle entrainment. Dredge Type Construction of the project will be accomplished using cutterhead suction dredges, trailing suction hopper dredges, or a combination of the two. To minimize impacts from hopper dredging, the project will follow the standard hopper dredging conditions outline in the 2020 South Atlantic Regional Biological Opinion. Dredge Positioning Navigation and positioning software will be used by the contractor to accurately track the dredge location. The software will provide real-time dredge positioning and digging functions to allow color display of dredge shape, physical feature data as found in background Computer Aided Design Application for Major Development Permit Town of Duck Shore Protection Project C OASTA L P ROTECTION E NGI NEERI NG OF N ORTH C A RO LINA , I NC . 14 (CAD) charts and color contour matrix files from hydrographic data collection software described above. The software will also provide a display of theoretical volume quantities removed during actual dredging operations. Dredge anchors will not be placed any further than 200 feet from the edge of the areas to be dredged. The dredge contractor will be required to verify the location of the anchors with real time positioning each and every time the anchors are relocated. Pipeline Positioning The pipeline alignment along the beach will be placed to avoid potential piping plover habitat or sea turtle nests. The alignment will be coordinated with, and approved by, the USACE. As-built positions of the pipeline will be recorded using GPS technology and included in the final construction observation report. Pipeline Observations Observations and assessments of the pipeline during construction will be performed to avoid pressurized leaks from the pipeline couplings or other equipment that may result in sediment plumes, siltation and/or elevated turbidity levels. The Towns, along with the associated engineer, will coordinate with the dredgers and have in place a mechanism to cease dredge and fill activities in the event that a substantial leak is detected in the event that a substantial leak is detected (leaks resulting in turbidity that exceed state water quality standards). The contractor will cease dredge and placement activities until an appropriate repair of the affected equipment has been completed. Construction Observations Several initiatives will be undertaken by the Town, the Engineer, or his duly authorized representative to monitor construction practices. Construction observation and contract administration will be periodically performed seven days/week, approximately twelve hours/day during periods of active construction. Most observations will be during daylight hours; however, random nighttime observations may be conducted. The Town, the Engineer, or his duly authorized representative will provide onsite observation by an individual with training or experience in beach nourishment and construction observation and testing, and that is knowledgeable of the project design and permit conditions. The project manager will coordinate with the field observer. Multiple daily observations of the pump-out location will be made for quality assessment and quality control (QA/QC) of the material being placed on the beach. The construction contractor will provide observations 24 hours per day during construction. Sediment Compatibility The Sediment Criteria Rule provides beneficial guidelines for both grain size and percent weight of calcium carbonate. However, other important characteristics such as organic content, heavy mineral content and color are not addressed. These aspects of the beach material will be considered. Maintaining adherence to this sediment criteria rule for material placed on the beach will reduce adverse impacts to the beach invertebrate community and would also reduce effects to sea turtle nest construction and incubation of the eggs. Multiple daily observations of the active placement locations will be made for QA/QC of the material being placed on the beach. The individual will collect a representative sub-surface (6 in. below grade) grab sediment sample at not less than 200-foot intervals along the newly constructed berm to visually assess grain size, wet Munsell color, granul ar, gravel, and silt content. Application for Major Development Permit Town of Duck Shore Protection Project C OASTA L P ROTECTION E NGI NEERI NG OF N ORTH C A RO LINA , I NC . 15 Each sample will be archived with the date, time, and location of the sample. Samples will be collected during beach observations. The sample will be visually compared to the acceptable sand criteria. If determined necessary by the Engineer, or his duly authorized representative, quantitative assessments of the sand will be conducted for grain size, wet Munsell color, and content of gravel, granular and silt. A record of these sand evaluations will be provided within the Engineer’s daily inspection reports and submitted to USACE and DCM for verification. Following construction, compaction of placed fill material will be inspected by the Town, the Engineer or his duly authorized representative in coordination with the DCM and USA CE. Compaction monitoring will begin after the material has been graded and dressed to the final slope and a period of time will be allowed for finer particles to be washed away and final settling of the material to occur prior to compaction monitoring. If the fill material appears to have a higher degree of compaction than that which is acceptable additional testing such as cone penetration testing will be considered. After subsequent testing, if it is determined that tilling is necessary to reduce compaction based on consultation with the appropriate agencies, the contractor will till the beach to a minimum depth of 36 inches throughout the constructed portion of the beach to loosen the compaction of the placed material. Beach tilling will only be performed as a result of an identified compaction problem based on agency consultation. Beach compaction monitoring and, if necessary, tilling would ensure that project impacts on sea turtle nesting are minimized. Escarpments Visual surveys of escarpments will be made along the beach fill area immediately after completion of construction. Escarpments in the newly placed beach fill that exceed 18 inches for greater than 100 ft. shall be graded to match adjacent grades on the beach. Removal of any escarpments during the sea turtle hatching season (May 1 through November 15) shall be coordinated with the NCWRC, USFWS and the USACE. The likelihood of escarpment formation can be reduced by incorporating a beach design that closely resembles the native beach in terms of berm elevation, sediment size, and sediment sorting characteristics. The proposed project will be designed with a berm elevation of +6 ft. NAVD88, and sediment characteristics that fall within the ranges required by the North Carolina State Sediment Criteria. Water Quality During construction, shore parallel berms will be constructed on the beach to reduce nearshore turbidity impacts. These berms are designed such that the slurry will run parallel to shore, allowing sediment to settle out before the water is returned to the ocean. Turbidity monitoring during construction will be managed by the contractor. The contractor will be responsible for notifying the construction engineer in the event that turbidity levels exceed the state water quality standards. Measures that could be taken to subsequently reduce turbidity include moving the dredge to a different location, or asking the contractor to extend the berm, which would allow more time for fines to settle out before the water flows back into the ocean. West Indian Manatee and Whale Monitoring During construction or dredging activities, the contractor will adhere to the “Guidelines for Avoiding Impacts to the West Indian Manatee” created by the USFWS. Full-time NMFS-certified endangered species observers wil l be present on the hopper dredge(s) to alert dredge operators of any whales or manatees in the area. In the event a whale or manatee is spotted, the ship’s Application for Major Development Permit Town of Duck Shore Protection Project C OASTA L P ROTECTION E NGI NEERI NG OF N ORTH C A RO LINA , I NC . 16 captain will make proper maneuvers to avoid collisions or injury to the marine mammals. Vessel operators will abide by the 10 kt (18.5 km/h) speed restrictions in any Dynamic Management Areas (DMAs) that may be established while underway. Operators will abide by NMFS Southeast Region marine mammal viewing guidelines and maintain 50 yds. from sea turtles and dolphins and 100 yds. from whales. Vessel operators will also follow the restricted vessel approach of 500 yds. established for North Atlantic right whales. Participation in the Right Whale Early Warning System is required; therefore, dredging within right whale critical habitat from December through March will follow the protocol established within the Early Warning System (NMFS, 1995). Sea Turtle Monitoring and Relocation Trawling Risk of entrainment will be reduced by use of a sea turtle deflector on the dredge's draghead. Every effort will be made to keep the dredge pumps disengaged when the hopper dredge dragheads are not firmly on the bottom. Also, the rotating cutterhead will not be lifted from the sediment surface during operations. Additionally, full-time NMFS-certified protected species observers will be present on the hopper dredge to document any sea turtle activity and monitor turtle takes through screening of inflow and/or outflow. Dredging operations will abide by the terms and conditions deemed necessary to minimize hopper dredging impacts to sea turtles set forth in the 2020 South Atlantic Regional Biological Opinion (SARBO). On the beach, artificial lighting used during nighttime construction activities will be angled or shielded to reduce deterrence of sea turtle nesting and hatchling disorientation. A sea turtle nest monitoring and avoidance/relocation plan will be implemented through coordination with USFWS and NCWRC. This monitoring will be performed by trained individuals knowledgeable of the beach construction operations. Should hopper dredges be utilized, the proposed project may employ relocation trawling as a means to reduce the potential for entrainment. If relocation trawling is implemented, standard relocation trawling conditions will be observed as set forth by NMFS, including specification for trawl time, handling, holding conditions, take and release and any tagging, etc. A sea turtle nest monitoring plan will be implemented through coordination with USFWS and NCWRC. Dare County is included in surveys conducted by Network for Endangered Sea Turtles (N.E.S.T), the volunteer organization which performs systematic surveys of the northern Outer Banks from the Virginia border to the southern tip of Nags Head. Surveys are performed throughout the nesting season (May through August), and include daily morning patrols to mark and protect newly laid nests, as well as monitoring during incubation period and emergence. These surveys have been performed since 1981. Because the proposed project includes nourishment during the summer months (nesting season), monitoring will be needed to identify, and subsequently avoid burial or excavation of, existing nests during construction. This monitoring will be performed by trained individuals knowledgeable of the beach construction operations. In addition to monitoring surveys, nest Application for Major Development Permit Town of Duck Shore Protection Project C OASTA L P ROTECTION E NGI NEERI NG OF N ORTH C A RO LINA , I NC . 17 relocation will be implemented by highly trained individuals and in coordination with the appropriate agencies. Bird Monitoring Although a project-specific bird monitoring plan will not be d eveloped, existing programs established by the State, Cape Hatteras National Seashore, and other entities are anticipated to continue monitoring piping plovers, rufa red knots, and other bird species along portions of the Outer Banks in Dare County. In addition, all personnel involved in the construction process along the beach will be trained to recognize the presence of piping plovers and red knots prior to the initiation of beach construction. Personnel will be provided photos of each species, which will be required to be kept at the construction site for quick reference. A contractor representative authorized to stop or redirect work will conduct a shorebird survey prior to 9:00 am each day of sand placement activities. The survey will cover the work area and any locations where equipment is expected to travel. The contractor will note any observance of red knots or piping plovers and submit observations to the USACE Wilmington District Office the next calendar day. 2.1.3 Construction Schedule The inclement weather typically encountered during the winter months offshore the northern outer banks makes dredging difficult and often reduces dredging efficiencies, especially when cutterhead dredges are used. Elevated sea states poses a substantial safety risk to crews and equipment, while weather-related down times raise costs and reduce efficiency. As such, the Town proposes a year-round construction window with a high likelihood that construction would occur during the calmer and safer summer months. A year-round construction window would provide the contractor the most flexibility and provide a safer and more economical work environment. To allow for the greatest scheduling flexibility, no start and end date will be specified; rather, this will remain at the discretion of the contractor, and will be based on equipment availability and weather conditions. The Duck project could be constructed independently, or concurrently with the other three towns' projects. Based on estimated production rates, the Duck project will likely require approximately 2.5 months if constructed independently. If all four projects are constructed concurrently, the entire project would likely be completed within 5 months. These timeframes are based on the production rates for hopper dredges achieved during the 2017 multi-town project and the 2010-2011 Nags Head project. 2.1.4 Borrow Area and Sediment Analysis Beach quality sand would be dredged from an Outer Continental Shelf borrow area using a self-contained ocean- certified hopper dredge, a cutterhead pipeline dredge, or a combination of the two. The borrow area, "Borrow Area A" was previously used during the 2017 Dare County Multi-Beach Nourishment project and is located entirely within federal waters, i.e. seaward of the Three Nautical Mile Line, placing it under the BOEMs jurisdiction (Appendix A, sheets 1 and 2). Prior to the 2017 nourishment project, Coastal Protection Engineering, Inc. of North Carolina (CPE) conducted a comprehensive offshore sand search using a systematic methodology involving three sequential phases of investigation. Phase I involved a comprehensive desktop study that examined previously collected information within the geologic context of the investigation area in order to identify features with the highest potential of containing project compatible sand. Results of jetprobe investigations of several shoal features offshore Dare County conducted by CPE in 2013 as part of a feasibility study for the Town of Kill Devil Hills were also Application for Major Development Permit Town of Duck Shore Protection Project C OASTA L P ROTECTION E NGI NEERI NG OF N ORTH C A RO LINA , I NC . 18 considered during this phase. Details of the findings of Phase I can be found in the full geotechnical report (Appendix C, beginning on page 15). Surveying, sampling and analysis of the Duck native beach was also conducted during Phase I. In keeping with the requirements set forth in the North Carolina State Sediment Criteria, shore-perpendicular topographic and bathymetric surveys of the native beach were conducted to determine the beach profile. The locations of the profiles surveyed by CPE were based on a data set previously collected by the US Army Corps of Engineers Field Research Facility. CPE surveyed a total of 34 profiles along the Duck oceanfront in September 2013 and May 2015; 9 of these profiles fall within the limits of the proposed project. Each profile survey extended from a point 150 feet landward of the vegetation line seaward to an elevation no less than -25 ft. NAVD88. Characterization of the Duck native beach was generated from samples collected along five generally evenly-spaced profiles within the project area: profiles D-11, D-13, D-15, D-17 and D-18 (Appendix C, Figure 6). As required by the State Sediment Criteria, samples were taken at thirteen locations along each profile, including: the dune, toe of dune, mid-berm, berm crest, mean high water, mean tide level, mean low water, trough, bar crest and at -12.5, -15.0, -17.5 and -20.0 NAVD83. In total, CPE collected 65 samples within the proposed project area in Duck. The composite summary and grain size analysis results of these samples are displayed in Table 1 below. Additionally, the results of sediment analysis for each sediment sample can be found within the Beach Composite Summary Tables provided in Appendix 4 of the attached Appendix C. Along with ensuring compatibility of the sand characteristics, the State Sediment Criteria also require quantification of clasts (rocks and shell) greater than 3-inches in diameter present on the native beach. As such, CPE conducted a pre-construction survey in June 2020 to determine the background levels of clasts (rocks) greater than 3-inches that exist along the Town of Duck's oceanfront beach between MLW and the frontal toe of the dune. Per the updated State Sediment Criteria language, the number of 3-inch clasts were quantified within five (5) 10,000 sq ft.2 sections along the beach. Results identified 267 clasts greater than 3-inches within the survey area. The criteria stipulate that borrow area material greater than 3-inches in diameter that is placed in the project area is considered incompatible if it is more than twice the background level that existed on the native beach before the project began. Since the June 2020 survey, the State has updated their guidance again and now also require a survey, using the same methodology described above, to determine the total number of sediments greater than or equal to one inch in diameter. Although this survey has not been conducted at this time, the applicant will perform it prior to the implementation of the proposed project. Information gathered during the Phase I archival literature studies regarding the geological setting of the project area give no indication that hardbottom habitats are present within or in the vicinity of the borrow areas. Additionally, previous geotechnical and geophysical investigations conducted by the USACE have not indicated the presence of hardbottoms in the area. Finally, analysis of the sidescan sonar data acquired by CPE for the present project indicated no presence of hardbottom habitats or consolidated rock exposures or outcroppings within or in the vicinity of the borrow area. Phase II investigations involved reconnaissance level geophysical surveys in order to 1) define the extent of sediment layers identified during Phase I research of pastjetprobe data and historic vibracore and surface sediment data; 2) develop a vibracore plan to be implemented during Phase III investigations, and 3) identify potential environmental or cultural resources for avoidance during Phase III vibracore investigations. Results of the geotechnical investigations, including geophysical (sonar) surveys, vibracores, hydrographic surveys, archaeological resource surveys and sand compatibility analyses were used to develop the proposed borrow area design. Design considerations for the proposed borrow area included: Construction of the project may be accomplished using a hopper or cutterhead dredge Application for Major Development Permit Town of Duck Shore Protection Project C OASTA L P ROTECTION E NGI NEERI NG OF N ORTH C A RO LINA , I NC . 19 Location of sufficient sand to construct the four proposed beach nourishment projects for the Towns of Duck, Southern Shores, Kitty Hawk, and Kill Devil Hills Beach compatible sand with similar mean grain size and sorting of the project beaches Avoidance of environmentally sensitive areas such as hardbottom, seagrass beds, etc. Avoidance of potentially significant cultural resources Avoidance of nearshore impacts due to wave refraction over borrow areas The proposed design cuts for Borrow Area A are displayed in sheets 9 and 10 of Appendix A. Borrow Area A has been divided into seven different design cuts with cut depths ranging from -58.5 to -68.0 ft. (Figure 1). The sediment compatibility analysis, as summarized in Table 1, determined that the offshore borrow material in Borrow Area A meets the compatibility requirements established by the North Carolina Coastal Resources Commission (CRC) prior to the 2017 nourishment event. It is the position of the applicants engineering consultant that the previous sediment compatibility analysis (Table 1) remains valid for Borrow Area A. Through correspondence with Division of Coastal Management staff, the applicant was notified that DCM has some concerns about the compatibility of the material in areas previously dredged. Cuts A3, A4, and A5 have been identified as portions of the borrow area not previously dredged during the 2017 construction project. Collectively these three cuts contain 5,153,700 cy of material which, at this time is anticipated to contain enough volume for this proposed project as well as the three other towns in Dare County seeking permits for similar actions. Given concerns expressed by DCM staff regarding sediment compatibility of portions of the borrow area previously dredged and the desire to give the dredge contractor flexibility on where they can dredge within Borrow Area A, the applicant requests DCM consider conditioning the permit to require the applicant to conduct updated bathymetric surveys and sediment sampling of portions of the borrow area previously dredged (Cuts A1, A2, A6, and A7) to evaluate the potential for infilling and sediment compatibility, prior to construction of the project. The additional bathymetric surveys and sediment sampling would need to demonstrate sediment compatibility of any sediment that has infilled previously dredged areas. It is the applicant’s intent to conduct such surveys and sediment sampling/analysis during the months of April and May of 2021. To maintain the project schedule, the applicant has determined that permit decisions need to be made prior to August 2021. The recommended course of action would allow for DCM to continue its permit review while providing the applicant time to conduct the further investigations, which would be incorporated into bidding documents prior to the project being advertised for bid. Table 1. Results of the compatibility analyses performed for Borrow Area A. Allowable limits for the Town of Duck native beach are in accordance with Rule 15A NCAC 07H.0312. Parameter Duck Native Beach Allowable Limits for Duck Native Beach Borrow Area A Wet/Dry Munsell Value 5/6 n/a 5/6 Mean Grain Size (mm) 0.33 n/a 0.36 Sorting (Phi) 1.32 n/a 1.47 Silt (%) (<0.0625mm) 1.01 6.01 0.83 Granular (%) (2mm < and < 4.76mm)3.89 8.89 1.42 Gravel (%) (>4.76mm) 2.0 7.0 0.47 Carbonate 2.0 17.00 1.0 Ap p l i c a t i o n f o r M a j o r D e v e l o p m e n t P e r m i t To w n o f D u c k S h o r e P r o t e c t i o n P r o j e c t C O A S T A L P R O T E C T I O N E N G I N E E R I N G O F N O R T H C A R O L I N A , I N C . 2 0 Fi g u r e 1 . M a p o f B o r r o w A r e a A , s h o w i n g p r e l i m i n a r y d e s i g n c u t s a n d e s t i m a t e d v o l u m e s . Application for Major Development Permit Town of Duck Shore Protection Project C OASTA L P ROTECTION E NGI NEERI NG OF N ORTH C A RO LINA , I NC . 21 To determine project impacts on potentially significant submerged cultural resources, Tidewater Atlantic Research (TAR) carried out a background literature review and supervised a cultural resource investigation of the proposed borrow areas. The resulting cultural resource report compiled by TAR is provided in Appendix B. A registered archaeologist from TAR identified 9 magnetic anomalies in the vicinity of Area A, 4 of which were considered potentially significant (Appendix A, sheet 12). As a result, three buffer areas were established within Borrow Area A – two are located within the borrow area and one is located partially outside the western perimeter (Appendix A, sheet 12). These areas will be avoided during dredging. 2.1.5 Summary of Consistency with State Sediment Criteria Provided below is a summary of how each criterion stipulated in 15A NCAC 07H .0312 Technical Standards for Beach Fill Standards have been adhered to. Those criteria not considered applicable to the project, such as those pertaining to projects utilizing a borrow area located in a maintained navigation channel, have been omitted. Table 2. Statement of consistency with each criteria within the 15A NCAC 07H .0312 Technical Standards for Beach Fill Standards, and location of information within the supporting documentation. Section (15A NCAC 07H .0312) Description Statement of Consistency: (1)(c) Topographic and Bathymetric Surveys Shore-perpendicular bathymetric and topographic surveys of the beach, were conducted in Sept. 2013 and May 2015 along transects spaced approximately 1,000 ft. apart within the project area. Please refer to Dare County, NC Duck - Kitty Hawk - Kill Devil Hills 2015 Hydrographic and Topographic Survey Report (Appendix D) for a description of methodology and cross section plots. (1)(d) Beach Sediment Sampling Locations 13 sediment samples were collected from 5 representative beach profiles along the project area, spaced approximately 2,000 ft. apart. Samples were taken from each of the morphodynamic zones specified: 1 sample was collected at MLW and 6 samples were collected both seaward and landward of the MLW. Please refer to Beach Characterization section under Phase 1 Investigations in Appendix C: Comprehensive Marine Sand Search and Borrow Area Design Report (1)(e) Values for four (4) Sediment Grain Size Categories (Individual Samples) Mechanical sieve analysis was performed on each of the samples. The percent by weight of each of the 4 grain size categories (fine, sand, granular, and gravel) for each individual sample is provided in the Percentage of Material by Sediment Grain Size Category table in Appendix 4 of the Comprehensive Marine Sand Search and Borrow Area Design Report (Appendix C). (1)(f) Composite Values for four (4) sediment grain Size Categories Composite values of the percent by weight of each of the 4 grain size categories were developed. Please refer to the Percentage of Material by Sediment Grain Size Category table in Appendix 4 of the Comprehensive Marine Sand Search and Borrow Area Design Report (Appendix C) (1)(g) Percent Calcium Carbonate Carbonate analysis was performed on a composite sample of all sediment samples along each of the 5 profiles. Please refer to the Profile Line Composite Summary Table in Appendix 4 of the Comprehensive Marine Sand Search and Borrow Area Design Report (Appendix C). (1)(h) Total Number of Clasts > 3 inches (76 mm) in diameter In June 2020, as per the updated State Sediment Criteria language, CPE conducted a survey to quantify the number of 3-inch clasts within five (5) 10,000 sq ft.2 sections along the beach. Results identified 267 clasts greater than 3-inches within the survey area. Application for Major Development Permit Town of Duck Shore Protection Project C OASTA L P ROTECTION E NGI NEERI NG OF N ORTH C A RO LINA , I NC . 22 (2)(c) Seafloor Bathymetry and Sonar Imagery Over the course of two surveys (June 2014 and October 2014) seafloor surveys were conducted such that 100 percent coverage of each submarine borrow area was obtained. Both single beam bathymetry and high resolution sides scan sonar imagery were collected. Please refer to descriptions of the Phase II Investigations and Phase III Investigations in the Comprehensive Marine Sand Search and Borrow Area Design Report (Appendix C). (2)(d) Geophysical imaging of seafloor subsurface (Subbottom Survey) Over the course of two surveys (June 2014 and October 2014) geophysical imaging of the seafloor subsurface was used to characterize the submarine borrow area. A sub-bottom profiler was used to survey tracklines spaced approximately 30-m apart, which greatly exceeds the state standard. Please refer to Phase II Investigations and Phase III Investigations in the Comprehensive Marine Sand Search and Borrow Area Design Report (Appendix C). (2)(e) Vibracore Spacing, Number, and Recovery Depth Sediment sampling of Borrow Area A used a 271B Alpine Pneumatic vibracore, configured to collect undisturbed sediment cores up to 20 ft. in length. Material is fed into a 3-inch diameter plastic core liner, which is split and sampled. Vibracores were collected at 1,000-foot spacing. 51 vibracores were collected within Borrow Area A for an average acreage per core of 23. Refer to figures 21 and 22 in the Comprehensive Marine Sand Search and Borrow Area Design Report (Appendix C) for spacing of vibracores within each borrow area. All vibracores within a given borrow area cut section penetrated and recovered material from below the proposed cut depth (i.e. all vibracores within a section marked cut to -65 ft. recovered material from at least a depth of -65 ft.) Please refer to Figures 21 and 22 and the vibracore logs in Appendix 11 of the Comprehensive Marine Sand Search and Borrow Area Design Report (Appendix C) to verify depths recovered. (2)(g) Grain size analysis of individual vibracore samples and borrow area composites Mechanical seive analysis was performed on each of the samples. The percent by weight of each of the 4 grain size categories (fine, sand, granular, and gravel) for each individual sample is provided in the Percentage of Material by Sediment Grain Size Category table in Appendix 16 of the Comprehensive Marine Sand Search and Borrow Area Design Report. Weighted composite values of the percent by weight of each of the 4 grain size categories were developed for each core and ultimately composite values were developed for the borrow area. These composites are also provided in the Percentage of Material by Sediment Grain Size Category table in Appendix 16 of the Report. Summary values for each borrow area are provided in Table 6 of the report. (2)(h) Vibracore calcium carbonate composites Carbonate analysis was performed on each vibracore sample. A weighted percent calcium carbonate value was computed for each vibracore. These values were used to determine the weighted percent calcium carbonate composite value for Borrow Area A. Please refer to the Cumulative Percents and Computed Distributions table in Appendix 16 of the Report (Appendix C) for individual sample percentage and weighted composite vibracore percentage. Please refer to the Composite Data Table in Appendix 16 of the Report for weighted composite vibracore and borrow area percentage. Summary values for each borrow area can also be found in the text of the Report in Table 6. (3)(b) Fine-Grained Size Sediment Compatibility The average percentage by weight of fine-grained sediment in each borrow site does not exceed the average percentage by weight of fine-grained sediment of the recipient beach characerization plus five percent. See Table 1 of the project narrative, and Table 6 of the Comprehensive Marine Sand Search and Borrow Area Design Report (Appendix C). Application for Major Development Permit Town of Duck Shore Protection Project C OASTA L P ROTECTION E NGI NEERI NG OF N ORTH C A RO LINA , I NC . 23 (3)(c) Granular Size Compatibility The average percentage by weight of granular sediment in each borrow site does not exceed the average percentage by weight of fine-grained sediment of the recipient beach characerization plus five percent. See Table 1 of the project narrative, and Table 6 of the Comprehensive Marine Sand Search and Borrow Area Design Report (Appendix C). (3)(d) Gravel Size Compatibility The average percentage by weight of gravel in each borrow site does not exceed the average percentage by weight of fine-grained sediment of the recipient beach characerization plus five percent. See Table 1 of the project narrative and Table 6 of the Comprehensive Marine Sand Search and Borrow Area Design Report (Appendix C). (3)(e) Calcium Carbonate Compatibility The average percentage by weight of calcium carbonate in each borrow site does not exceed the average percentage by weight of fine-grained sediment of the recipient beach characterization plus 15 percent. See Table 1 of the project narrative and Table 6 of the Comprehensive Marine Sand Search and Borrow Area Design Report (Appendix C). (4)(a) Sediment Excavation Depths All vibracores within a given borrow area cut section penetrated and recovered material from below the proposed cut depth (i.e. all vibracores within a section marked cut to -65 ft. recovered material from at least a depth of -65 ft.).