Loading...
HomeMy WebLinkAboutAppendix C Addendum Clast InfoCOASTAL PROTECTION ENGINEERING OF NORTH CAROLINA, INC. 1 TOWN OF DUCK, SOUTHERN SHORES, KITTY HAWK, AND KILL DEVIL HILLS, NORTH CAROLINA BORROW AREA INVESTIGATION AND SEDIMENT COMPATIBILITY ANALYSIS ADDENDUM A – LARGE SEDIMENT AND SHELL ASSESSMENT This document is an addendum to the Borrow Area Investigation and Sediment Compatibility Analysis Report: Town of Duck, Southern Shores, Kitty Hawk, and Kill Devil Hills, North Carolina, prepared by Coastal Protection Engineering of North Carolina, Inc. (CPE). The original report was prepared for the four (4) northern Dare County Towns and submitted on April 26, 2021. An updated assessment of the amount of large sediments (≥ 1 inch in diameter) and shell (≥ 3 inches in diameter) was requested by the North Carolina Division of Coastal Management due to amendments to the State’s Technical Standards for Beach Fill Projects (15A NCAC 07H .0312). The amended rules, which are included as Appendix 1, were adopted by the North Carolina Coastal Resources Commission (CRC) in February 2021. In May 2021, the Towns of Duck, Southern Shores, Kitty Hawk, and Kill Devil Hills, authorized CPE to conduct the necessary field data collection and assessment to adhere to the amended Technical Standards for Beach Fill Projects. This addendum is meant to update the information provided in Sections 2.1 and 2.2 of the Borrow Area Investigation and Sediment Compatibility Analysis Report: Town of Duck, Southern Shores, Kitty Hawk, and Kill Devil Hills, North Carolina. This Addendum includes the following appendices: •Appendix 1 --- Proposed Amendments for North Carolina Technical Standards for Beach Fill Projects (15A NCAC 07H .0312) •Appendix 2 --- Dare County Sampling Transects •Appendix 3 --- Dare County Large Sediment and Shell Survey Results •Appendix 4 --- Digital Files Introduction: Between June 11 and June 13, 2020, CPE conducted large clast surveys for the Towns of Duck, Southern Shores, Kitty Hawk, and Kill Devil Hills. CPE based the methodology of those surveys on proposed amended rule changes to the State’s Technical Standards for Beach Fill Projects, that were being considered in the Summer of 2020. In February 2021, the North Carolina Coastal Resources Commission (CRC) adopted amendments to the Technical Standards (Appendix 1), which differed from those that were being proposed in summer 2020. Specifically, the proposed amendments modify Section (1)(h), which governs the sampling protocols for large sediments and shell material on a native or recipient beach. Under the proposed amendments, the number of large sediments greater than or equal to one inch in diameter and shell material greater than Dare County, NC Borrow Area Investigation and Sediment Compatibility Analysis Addendum A COASTAL PROTECTION ENGINEERING OF NORTH CAROLINA, INC. 2 or equal to three inches in diameter on the recipient beach shall be counted by a visual observation survey. Surveys must be conducted along a minimum of five (5) shore-perpendicular transects evenly spaced throughout the entire project area with spacing between transects not exceeding 5,000 feet in the shore-parallel direction. At each transect, a 10,000 square foot area between the toe of dune and mean tide level shall be surveyed for large sediments and shells by visual observation. Finally, an arithmetic mean shall be computed for both sediments and shells by summing the totals for each across all transects and dividing by the number of transects. Methodology: CPE conducted visual observation surveys in the Towns of Duck, Southern Shores, Kitty Hawk, and Kill Devil Hills in April 2021. Twenty-one (21) sampling transects were established across the four Towns: five (5) in Duck, six (6) in Southern Shores, five (5) in Kitty Hawk, and five (5) in Kill Devil Hills. Sampling transects were generally evenly spaced along the project areas, with spacing not exceeding 5,000 feet in the shore-parallel direction between consecutive transects. Coordinates of the transects surveyed are provided in Appendix 2. At each transect, a 10,000 square foot area was staked out between the toe of dune and the mean tide level. The mean tide level (NAVD88 ft) is -0.44 ft. for all four towns. The coordinates of the four (4) corners of each survey area were measured using a Real Time Kinematic (RTK) Global Positioning System (GPS) and are provided in Appendix 3. Horizontal data were collected in the North Carolina State Plane Coordinate System, North American Datum of 1983 (NAD83). Vertical data were collected in the North American Vertical Datum of 1988 (NAVD88). After the survey area was delineated, sediments greater than or equal to one inch and shell material greater than or equal to three inches in diameter were counted by a visual observation survey. Upon completion of the surveys, an arithmetic mean was computed for both sediments and shells in each town. A summary of the survey dates and list of sampling transects for the Towns of Duck, Southern Shores, Kitty Hawk, and Kill Devil Hills are provided below. • On April 26th, 2021, CPE conducted a survey of five 10,000 square foot areas in Duck (D- 11, D-13, D-15, D-17, D-18) (Figure 1). • On April 26th, 2021, CPE conducted a survey of six 10,000 square foot areas in Southern Shores (-197+12, -170+56, -130+00, -90+00, -50+00, -10+00) (Figure 2). • On April 26th, 2021, CPE conducted a survey of five 10,000 square foot areas in Kitty Hawk (9+99, 50+28, 75+00, 109+99, 159+99) (Figure 3). • On April 28th, 2021, CPE conducted a survey of five 10,000 square foot areas in Kill Devil Hills (209+74, 235+00, 260+17, 289+99, 320+05) (Figure 4). Dare County, NC Borrow Area Investigation and Sediment Compatibility Analysis Addendum A COASTAL PROTECTION ENGINEERING OF NORTH CAROLINA, INC. 3 To ensure the accuracy of the RTK GPS equipment, horizontal and vertical positioning checks were conducted at the beginning and end of the day using two 2nd order monuments from the National Geodetic Survey (NGS). The RTK GPS was used within a virtual reference station (VRS) network to locate and confirm survey control for this project. The control check shots were acquired using a minimum of five (5) epochs which results in high accuracy location. The horizontal and vertical accuracy of control data meets the accuracy requirements as set forth in the Engineering and Design Hydrographic Surveying Manual (EM 1110-2-1003). Results: A summary of the results for the Towns of Duck, Southern Shores, Kitty Hawk, and Kill Devil Hills are provided below and in Tables 1, 2, 3, and 4. Results for individual transects are provided in Appendix 3. • Five transects in Duck were surveyed (D-11, D-13, D -15, D-17, D-18) (See Figure 1). A total of 15 sediments greater than or equal to one inch and 54 shells greater than or equal to three inches were counted across all five transects surveyed along the Town of Duck shoreline. The arithmetic means for large sediments and shell material within the project area is 3.0 and 10.8, respectively. Table 1 includes a summary of the results for Duck. Appendix 3 includes detailed information for each transect sampled. Table 1. Duck Data Summary Stations Arithmetic Mean Total Sediment ≥ 1 Inch Shell ≥ 3 Inch Sediment ≥ 1 Inch Shell ≥ 3 Inch All Transects 3.0 10.8 15.0 54.0 (D-11, D-13, D-15, D-17, D-18) Dare County, NC Borrow Area Investigation and Sediment Compatibility Analysis Addendum A COASTAL PROTECTION ENGINEERING OF NORTH CAROLINA, INC. 4 Figure 1. Map showing locations of the survey transects in the Town of Duck • Six transects in Southern Shores were surveyed (-197+12, -170+56, -130+00, -90+00, -50+00, -10+00) (See Figure 2). A total of 123 sediments greater than or equal to one inch and 30 shell material greater than or equal to three inches were counted across all six transects. The arithmetic means for large sediments and shell material within the project area is 20.5 and 5.0, respectively. Table 2 includes a summary of results for Southern Shores. Appendix 3 includes detailed information for each transect sampled. Table 2. Southern Shores Data Summary Stations Arithmetic Mean Total Sediment ≥ 1 Inch Shell ≥ 3 Inch Sediment ≥ 1 Inch Shell ≥ 3 Inch All Transects 20.5 5.0 123.0 30.0 (-197+12, -170+56, -130+00, -90+00, -50+00, -10+00) Dare County, NC Borrow Area Investigation and Sediment Compatibility Analysis Addendum A COASTAL PROTECTION ENGINEERING OF NORTH CAROLINA, INC. 5 Figure 2. Map showing locations of the survey transects in the Town of Southern Shores • Five transects in Kitty Hawk were surveyed (9+99, 50+28, 75+00, 109+99, 159+99) (See Figure 3). A total of 9 sediments greater than or equal to one inch and 49 shells greater than or equal to three inches were counted across all five transects. The arithmetic means for large sediments and shell material within the project area is 1.8 and 9.8, respectively. Table 3 includes a summary of results for Kitty Hawk. Appendix 3 includes detailed information for each transect sampled. Table 3. Kitty Hawk Data Summary Stations Arithmetic Mean Total Sediment ≥ 1 Inch Shell ≥ 3 Inch Sediment ≥ 1 Inch Shell ≥ 3 Inch All Transects 1.8 9.8 9.0 49.0 (9+99, 50+28, 75+00, 109+99, 159+99) Dare County, NC Borrow Area Investigation and Sediment Compatibility Analysis Addendum A COASTAL PROTECTION ENGINEERING OF NORTH CAROLINA, INC. 6 Figure 3. Map showing locations of the survey transects in the Town of Kitty Hawk • Five transects in Kill Devil Hills were surveyed (209+74, 235+00, 260+17, 289+99, 320+05) (See Figure 4). A total of 9 sediments greater than or equal to one inch and 93 shells greater than or equal to three inches were counted across all five transects. The arithmetic means for large sediments and shell material within the project area is 1.8 and 18.6, respectively. Table 4 includes a summary of results for Kill Devil Hills. Appendix 3 includes detailed information for each transect sampled. Table 4. Kill Devil Hills Data Summary Stations Arithmetic Mean Total Sediment ≥ 1 Inch Shell ≥ 3 Inch Sediment ≥ 1 Inch Shell ≥ 3 Inch All Transects 1.8 18.6 9.0 93.0 (209+74, 235+00, 260+17, 289+99, 320+05) Dare County, NC Borrow Area Investigation and Sediment Compatibility Analysis Addendum A COASTAL PROTECTION ENGINEERING OF NORTH CAROLINA, INC. 7 Figure 4. Map showing locations of the survey transects in the Town of Kill Devil Hills Conclusions: In April 2021, CPE conducted visual observation surveys for large sediments and shell material along 21 transects in the Towns of Duck, Southern Shores, Kitty Hawk, and Kill Devil Hills. The surveys were conducted in accordance with the CRC’s amended Rule 15A NCAC 07H .0312 – Technical Standards for Beach Fill Projects, adopted in February 2021. Sediments greater than or equal to one inch in diameter and shell material greater than or equal to three inches in diameter were counted during the survey. Following the survey, an arithmetic mean was computed for both sediments and shell material in each town. A summary of the results is presented below in Table 5. Dare County, NC Borrow Area Investigation and Sediment Compatibility Analysis Addendum A COASTAL PROTECTION ENGINEERING OF NORTH CAROLINA, INC. 8 Table 5. Summary results of the visual observation surveys conducted in April 2021 for beach nourishment projects in northern Dare County, North Carolina Duck Southern Shores Kitty Hawk Kill Devil Hills Mean Number of Sediments (≥ 1 inch) 3.0 20.5 1.8 1.8 Mean Number of Shells (≥ 3 inches) 10.8 5.0 9.8 18.6 APPENDIX 1 PROPOSED AMENDMENTS FOR NORTH CAROLINA’S TECHNICAL STANDARDS FOR BEACH FILL PROJECTS – 15A NCAC 07H .0312 1 of 7 15A NCAC 07H .0312 is proposed for amendment as follows: 1 2 15A NCAC 07H .0312 TECHNICAL STANDARDS FOR BEACH FILL PROJECTS 3 Placement of sediment along the oceanfront shoreline is referred to in this Rule as "beach fill." Sediment used solely 4 to establish or strengthen dunes or shall conform to the standards contained in 15A NCAC 07H .0308(b). Sediment 5 used to re-establish state -maintained transportation corridors across a barrier island breach in a disaster area as 6 declared by the Governor is not considered a beach fill project under this Rule. Beach fill projects including beach 7 nourishment, dredged material disposal, habitat restoration, storm protection, and erosion control may be permitted 8 under the following conditions: 9 (1) The applicant shall characterize the recipient beach according to the following methodology: 10 methodology. Initial characterizations of the recipient beach shall serve as the baseline for 11 subsequent beach fill projects: 12 (a) Characterization of the recipient beach is not required for the placement of sediment 13 directly from and completely confined to a cape shoal system, or maintained navigation 14 channel or associated sediment basins within the active nearshore, beach or inlet shoal 15 system; system. For purposes of this Rule, “cape shoal systems” include Frying Pan Shoals 16 at Cape Fear, Lookout Shoals at Cape Lookout, and Diamond Shoals at Cape Hatteras; 17 (b) Sediment sampling and analysis shall be used to capture the three-dimensional spatial 18 variability of the sediment characteristics including grain size, sorting and mineralogy 19 within the natural system; 20 (c) Shore-perpendicular transects shall be established for topographic and bathymetric 21 surveying of the recipient beach shall be conducted to determine the beach profile. 22 beach.Topographic and bathymetric surveying shall occur along a minimum of five shore-23 perpendicular transects evenly spaced throughout the entire project area. area with spacing 24 not to exceed 5,000 feet (1,524 meters) in the shore-parallel direction. Each transect shall 25 extend from the frontal dune crest seaward to a depth of 20 feet (6.1 meters) or to the shore-26 perpendicular distance 2,400 feet (732 meters) seaward of mean low water, whichever is 27 in a more landward position. Transect spacing shall not exceed 5,000 feet (1,524 meters) 28 in the shore-parallel direction. Elevation data for all transects shall be referenced to the 29 North American Vertical Datum of 1988 (NAVD 88) and the North American Datum of 30 1983 (NAD 83); compliant with Chapter 56 (21 NCAC 56.1600) of the N.C. General 31 Statutes; 32 (d) No fewer than 13 sediment samples shall be taken along each beach profile transect. At 33 Along each transect, at least one sample shall be taken from each of the following 34 morphodynamic zones where present: frontal dune, frontal dune toe, mid berm, mean high 35 water (MHW), mid tide (MT), mean low water (MLW), trough, bar crest and at even depth 36 increments from 6 feet (1.8 meters) to 20 feet (6.1 meters) or to a shore-perpendicular 37 2 of 7 distance 2,400 feet (732 meters) seaward of mean low water, whichever is in a more 1 landward position. The total number of samples taken landward of MLW shall equal the 2 total number of samples taken seaward of MLW; 3 (e) For the purpose of this Rule, "sediment grain size categories" are defined as "fine" (less 4 than 0.0625 millimeters), "sand" (greater than or equal to 0.0625 millimeters and less than 5 2 millimeters), "granular" (greater than or equal to 2 millimeters and less than 4.76 6 millimeters) and "gravel" (greater than or equal to 4.76 millimeters and less than 76 7 millimeters). Each sediment sample shall report percentage by weight of each of these four 8 grain size categories; 9 (f) A composite of the simple arithmetic mean for each of the four grain size categories defined 10 in Sub-Item (1)(e) of this Rule shall be calculated for each transect. A grand mean shall 11 be established for each of the four grain size categories by summing the mean for each 12 transect and dividing by the total number of transects. The value that characterizes grain 13 size values for the recipient beach is the grand mean of percentage by weight for each grain 14 size category defined in Sub-Item (1)(e) of this Rule; 15 (g) Percentage by weight calcium carbonate shall be calculated from a composite of all 16 sediment samples along each transect defined in Sub-Item (1)(d) of this Rule. samples. 17 The value that characterizes the carbonate content of the recipient beach is a grand mean 18 calculated by summing the average percentage by weight calcium carbonate for each 19 transect and dividing by the total number of transects. For beaches on which fill activities 20 have taken place prior to the effective date of this Rule, the Division of Coastal 21 Management shall consider visual estimates of shell content as a proxy for carbonate 22 weight percent; 23 (h) The total number of sediments greater than or equal to one inch (25.4 millimeters) in 24 diameter, and shell material greater than or equal to three inches (76 millimeters) in 25 diameter, observable on the surface of the beach between mean low water (MLW) and the 26 frontal dune toe, shall be calculated for an area of 50,000 square feet (4,645 square meters) 27 within the beach fill project boundaries. This area is considered a representative sample of 28 the entire project area and referred to as the "background" value; diameter shall be 29 differentiated and calculated through visual observation of an area of 10,000 square feet 30 centered on each transect, and between mean tide level (MTL) and the frontal dune toe 31 within the beach fill project boundaries. A simple arithmetic mean shall be calculated for 32 both sediments and shell by summing the totals for each across all transects and dividing 33 by the total number of transects, and these values shall be considered representative of the 34 entire project area, and referred to as the “background” values for large sediment and large 35 shell material; 36 3 of 7 (i) Beaches that received sediment prior to the effective date of this Rule shall be characterized 1 in a way that is consistent with Sub-Items (1)(a) through (1)(h) of this Rule and shall may 2 use data collected from the recipient beach prior to the addition of beach fill. If such data 3 were not collected or are unavailable, a dataset best reflecting the sediment characteristics 4 of the recipient beach prior to beach fill shall be developed in coordination with the 5 Division of Coastal Management; and fill where data are available, and in coordination 6 with the Division of Coastal Management; and 7 (j) All data used to characterize the recipient beach shall be provided in digital and hardcopy 8 format to the Division of Coastal Management upon request. 9 (2) Characterization of borrow areas is not required if completely confined to a cape shoal system. For 10 the purposes of this Rule, “cape shoal systems” include the Frying Pan Shoals at Cape Fear, Lookout 11 Shoals at Cape Lookout, and Diamond Shoals at Cape Hatteras. The applicant shall characterize the 12 sediment to be placed on the recipient beach according to the following methodology: 13 (a) The characterization of borrow areas including submarine sites, upland sites, and dredged 14 material disposal areas shall be designed to capture the three-dimensional spatial variability 15 of the sediment characteristics including grain size, sorting and mineralogy within the 16 natural system or dredged material disposal area; 17 (b) The characterization of borrow sites shall may include sediment characterization data 18 provided by the Division of Coastal Management where available. These data can be found 19 in individual project reports and studies, and shall be provided by the Division of Coastal 20 Management upon request and where available; historical sediment characterization data 21 where available and collected using methods consistent with Sub-Items (2)(c) through 22 (2)(g) of this Rule, and in coordination with the Division of Coastal Management. 23 (c) Seafloor surveys shall measure elevation and capture acoustic imagery of the seafloor. 24 Measurement of seafloor elevation shall cover 100 percent percent, or the maximum extent 25 practicable, of each submarine borrow site and use survey-grade swath sonar (e.g. 26 multibeam or similar technologies) in accordance with current US Army Corps of 27 Engineers standards for navigation and dredging. technologies). Seafloor imaging without 28 an elevation component (e.g. sidescan sonar or similar technologies) shall also cover 100 29 percent percent, or the maximum extent practicable, of each borrow site and be performed 30 in accordance with US Army Corps of Engineers standards for navigation and dredging. 31 site. Because shallow submarine areas can provide technical challenges and physical 32 limitations for acoustic measurements, seafloor imaging without an elevation component 33 may not be required for water depths less than 10 feet (3 meters). Alternative elevation 34 surveying methods for water depths less than 10 feet (3 meters) may be evaluated on a 35 case-by-case basis by the Division of Coastal Management. Elevation data shall be tide- 36 and motion-corrected and referenced to NAVD 88 and NAD 83. Compliant with Chapter 37 4 of 7 56 (21 NCAC 56 .1600) of the N.C. General Statutes. Seafloor imaging data without an 1 elevation component shall be referenced to the NAD 83. All final seafloor survey data shall 2 conform to standards for accuracy, quality control and quality assurance as set forth by the 3 US Army Corps of Engineers (USACE). The current surveying standards for navigation 4 and dredging can be obtained from the Wilmington District of the USACE. Also be 5 compliant with Chapter 56 (21 NCAC 56 .1600) of the N.C. General Statutes. For offshore 6 dredged material disposal sites, only one set of imagery without elevation is required. 7 Sonar imaging of the seafloor without elevation is also not required for borrow sites 8 completely confined to maintained navigation channels, and for sediment deposition basins 9 within the active nearshore, beach or inlet shoal system; 10 (d) Geophysical imaging of the seafloor subsurface shall be used to characterize each borrow 11 site and shall use survey grids with a line spacing not to exceed 1,000 feet (305 meters). 12 Offshore dredged material disposal sites shall use a survey grid not to exceed 2,000 feet 13 (610 meters) and only one set of geophysical imaging of the seafloor subsurface is required. 14 Survey grids shall incorporate at least one tie point per survey line. site. Because shallow 15 submarine areas can pose technical challenges and physical limitations for geophysical 16 techniques, subsurface data may not be required in water depths less than 10 feet (3 meters), 17 and the Division of Coastal Management shall evaluate these areas on a case-by-case basis. 18 Subsurface geophysical imaging shall not be required for borrow sites completely confined 19 to maintained navigation channels, and for sediment deposition basins within the active 20 nearshore, beach or inlet shoal system, or upland sites. All final subsurface geophysical 21 data shall use accurate sediment velocity models for time-depth conversions and be 22 referenced to NAD 83; compliant with Chapter 56 (21 NCAC 56 .1600) of the N.C. General 23 Statutes; 24 (e) Sediment With the exception of upland borrow sites, sediment sampling of all borrow sites 25 shall use a vertical sampling device no less than 3 inches (76 millimeters) in diameter. 26 Characterization of each borrow site shall use no fewer than five evenly spaced cores or 27 one core per 23 acres (grid spacing of 1,000 feet or 305 meters), whichever is greater. 28 Characterization of borrow sites completely confined to maintained navigation channels or 29 sediment deposition basins within the active nearshore, beach or inlet shoal system shall 30 use no fewer than five evenly spaced vertical samples per channel or sediment basin, or 31 sample spacing of no more than 5,000 linear feet (1,524 meters), whichever is greater. Two 32 sets of sampling data (with at least one dredging event in between) from maintained 33 navigation channels or sediment deposition basins within the active nearshore, beach or 34 inlet shoal system system, or offshore dredged material disposal site (ODMDS) may be 35 used to characterize material for subsequent nourishment events from those areas if the 36 sampling results are found to be compatible with Sub-Item (3)(a) of this Rule. In submarine 37 5 of 7 borrow sites other than maintained navigation channels or associated sediment deposition 1 basins within the active nearshore, beach or inlet shoal system where water depths are no 2 greater than 10 feet (3 meters), geophysical data of and below the seafloor are not required, 3 and sediment sample spacing shall be no less than one core per six acres (grid spacing of 4 500 feet or 152 meters). Vertical sampling shall penetrate to a depth equal to or greater 5 than permitted dredge or excavation depth or expected dredge or excavation depths for 6 pending permit applications. All sediment samples shall be integrated with geophysical 7 data to constrain the surficial, horizontal and vertical extent of lithologic units and 8 determine excavation volumes of compatible sediment as defined in Item (3) of this Rule; 9 Because shallow submarine areas completely confined to a maintained navigation channel 10 or associated sediment basins within the active nearshore, beach or inlet shoal system can 11 pose technical challenges and physical limitations for vertical sampling techniques, 12 geophysical data of and below the seafloor may not be required in water depths less than 13 10 feet (3 meters), and shall be evaluated by the Division of Coastal Management on a 14 case-by-case basis; 15 (f) For offshore dredged material disposal sites, the grid spacing shall not exceed 2,000 feet 16 (610 meters). Characterization of material deposited at offshore dredged material disposal 17 sites after the initial characterization are not required if all of the material deposited 18 complies with Sub-Item (3)(a) of this Rule as demonstrated by at least two sets of sampling 19 data with at least one dredging event in between; 20 (g) (f) Grain size distributions shall be reported for all sub-samples taken within each vertical 21 sample for each of the four grain size categories defined in Sub-Item (1)(e) of this Rule. 22 Weighted averages for each core shall be calculated based on the total number of samples 23 and the thickness of each sampled interval. A simple arithmetic mean of the weighted 24 averages for each grain size category shall be calculated to represent the average grain size 25 values for each borrow site. Vertical samples shall be geo-referenced and digitally imaged 26 using scaled, color-calibrated photography; 27 (h) (g) Percentage by weight of calcium carbonate shall be calculated from a composite sample of 28 each core. A weighted average of calcium carbonate percentage by weight shall be 29 calculated for each borrow site based on the composite sample thickness of each core. 30 Carbonate analysis is not required for sediment confined to maintained navigation channels 31 or associated sediment deposition basins within the active nearshore, beach or inlet shoal 32 system; and 33 (i) (h) All data used to characterize the borrow site shall be provided in digital and hardcopy 34 format to the Division of Coastal Management upon request. 35 6 of 7 (3) The Division of Coastal Management shall determine sediment Compliance with these sediment 1 standards shall be certified by an individual licensed pursuant to Chapter 89C or 89E of the N.C. 2 General Statutes. Sediment compatibility is determined according to the following criteria: 3 (a) Sediment completely confined to the permitted dredge depth of a maintained navigation 4 channel or associated sediment deposition basins within the active nearshore, beach or inlet 5 shoal system is considered compatible if the average percentage by weight of fine-grained 6 (less than 0.0625 millimeters) sediment is less than 10 percent; 7 (b) The average percentage by weight of fine-grained sediment (less than 0.0625 millimeters) 8 in each borrow site shall not exceed the average percentage by weight of fine-grained 9 sediment of the recipient beach characterization plus five percent; 10 (c) The average percentage by weight of granular sediment (greater than or equal to 2 11 millimeters and less than 4.76 millimeters) in a borrow site shall not exceed the average 12 percentage by weight of coarse-sand sediment of the recipient beach characterization plus 13 10 percent; 14 (d) The average percentage by weight of gravel (greater than or equal to 4.76 millimeters and 15 less than 76 millimeters) in a borrow site shall not exceed the average percentage by weight 16 of gravel-sized sediment for the recipient beach characterization plus five percent; 17 (e) The average percentage by weight of calcium carbonate in a borrow site shall not exceed 18 the average percentage by weight of calcium carbonate of the recipient beach 19 characterization plus 15 percent; and 20 (f) Techniques that take incompatible sediment within a borrow site or combination of sites 21 and make it compatible with that of the recipient beach characterization shall be evaluated 22 on a case-by-case basis by the Division of Coastal Management. 23 (4) Excavation and placement of sediment shall conform to the following criteria: 24 (a) Sediment excavation depths for all borrow sites shall not exceed the maximum depth of 25 recovered core at each coring location; 26 (b) (a) In order to protect threatened and endangered species, and to minimize impacts to fish, 27 shellfish and wildlife resources, no excavation or placement of sediment shall occur within 28 the project area during times any seasonal environmental moratoria designated by the 29 Division of Coastal Management in consultation with other State and Federal agencies. 30 Agencies, unless specifically approved by the Division of Coastal Management in 31 consultation with other State and Federal agencies. The time limitations shall be established 32 during the permitting process and shall be made known prior to permit issuance; and 33 (c) (b) Sediment The total sediments with a diameter greater than or equal to one inch (25.4 34 millimeters), and shell material with a diameter greater than or equal to three inches (76 35 millimeters) is considered incompatible if it has been placed on the beach during the beach 36 fill project, is observed between MLW MTL and the frontal dune toe, and is in excess of 37 7 of 7 twice the background value of material of the same size along any 50,000-square-foot 1 (4,645 square meter) 10,000 square feet section of beach. beach within the beach fill project 2 boundaries. In the event that more than twice the background value of incompatible 3 material is placed on the beach, it shall be the permittee’s responsibility to remove the 4 incompatible material in coordination with the Division of Coastal Management and other 5 State and Federal resource agencies. 6 7 History Note: Authority G.S. 113-229; 113A-102(b)(1); 113A-103(5)(a); 113A-107(a); 113A-113(b)(5) and (6); 8 113A-118; 113A-124; 9 Eff. February 1, 2007; 10 Amended Eff. April 1, 2021; August 1, 2014; September 1, 2013; April 1, 2008. 11 APPENDIX 2 DARE COUNTY SAMPLING TRANSECTS FOR LARGE SEDIMENTS AND SHELL MATERIAL Profile Name X_Start Y_Start Azimuth Area D-11 2955158.10 909133.10 70.00 Duck D-13 2955874.30 907478.40 70.00 Duck D-15 2956628.60 905677.80 70.00 Duck D-17 2957333.70 903863.90 70.00 Duck D-18 2957718.80 902886.50 70.00 Duck -197+12 2962839.60 889616.10 70.00 Southern Shores -170+56 2963880.50 887172.90 66.60 Southern Shores -130+00 2965239.00 883452.00 65.30 Southern Shores -90+00 2967110.00 879895.00 62.60 Southern Shores -50+00 2968838.00 876228.00 62.60 Southern Shores -10+00 2970653.00 872721.00 62.60 Southern Shores 9+99 2971685.80 871003.30 62.60 Kitty Hawk 50+28 2973566.70 867441.70 62.20 Kitty Hawk 75+00 2974725.60 865241.39 62.20 Kitty Hawk 109+99 2976406.10 862189.90 61.50 Kitty Hawk 159+99 2978966.60 857895.30 59.60 Kitty Hawk 209+74 2981440.40 853579.10 59.60 Kill Devil Hills 235+00 2982703.51 851344.11 59.60 Kill Devil Hills 260+17 2983879.60 849166.00 61.90 Kill Devil Hills 289+99 2985305.30 846547.00 62.20 Kill Devil Hills 320+05 2986679.00 843873.00 62.00 Kill Devil Hills APPENDIX 3 CPE LARGE SEDIMENT AND SHELL MATERIAL SURVEY RESULTS FOR THE TOWNS OF DUCK, SOUTHERN SHORES, KITTY HAWK, AND KILL DEVIL HILLS Duck, NC Station Number of Clasts Corner Coordinates Sediment ≥ 1 Inch Shell ≥ 3 Inch x y D-11 4 16 1 2955574.7 903081.9 2 2955632.0 902989.4 3 2955519.4 902952.1 4 2955474.4 903040.3 D-13 2 12 1 2956263.7 903081.9 2 2956306.6 902989.4 3 2956233.5 902952.1 4 2956181.2 903040.3 D-15 4 9 1 2956996.0 903081.9 2 2957055.4 902989.4 3 2956966.8 902952.1 4 2956916.8 903040.3 D-17 5 14 1 2957728.0 903081.9 2 2957770.7 903974.5 3 2957665.6 902952.1 4 2957634.9 903040.3 D-18 0 3 1 2958105.0 903081.9 2 2958143.8 902989.4 3 2958035.2 902952.1 4 2958002.3 903040.3 Southern Shores, NC Station Number of Clasts Corner Coordinates Sediment ≥ 1 Inch Shell ≥ 3 Inch x y -197+12 79 12 1 2963224.6 889814.1 2 2963267.5 889721.1 3 2963142.3 889682.9 4 2963116.9 889757.9 -170+56 2 4 1 2964271.6 887391.4 2 2964303.3 887313.5 3 2964186.1 887261.0 4 2964157.0 887335.5 -130+00 6 5 1 2965864.8 883780.7 2 2965898.3 883707.1 3 2965785.5 883655.6 4 2965751.2 883728.0 -90+00 31 5 1 2967555.3 880173.1 2 2967588.0 880095.2 3 2967490.5 880047.1 4 2967453.7 880122.7 -50+00 0 1 1 2969281.2 876508.3 2 2969324.6 876424.9 3 2969224.4 876376.1 4 2969183.3 876460.2 -10+00 5 3 1 2971001.8 872936.7 2 2971033.8 872873.7 3 2970918.5 872817.4 4 2970886.2 872883.8 Kitty Hawk, NC Station Number of Clasts Corner Coordinates Sediment ≥ 1 Inch Shell ≥ 3 Inch x y 9+99 1 5 1 2971932.9 871172.5 2 2971968.7 871107.6 3 2971843.5 871041.7 4 2971809.8 871104.8 50+28 5 25 1 2973819.2 867609.4 2 2973853.1 867550.2 3 2973712.2 867480.2 4 2973680.9 867538.8 75+00 2 5 1 2974989.9 865414.8 2 2975015.9 865361.4 3 2974868.6 865285.5 4 2974841.4 865334.4 109+99 0 7 1 2976654.1 862376.4 2 2976690.7 862311.0 3 2976570.5 862242.6 4 2976536.5 862307.8 159+99 1 7 1 2979152.9 858062.8 2 2979208.5 857977.4 3 2979112.6 857924.5 4 2979064.1 858004.4 Kill Devil Hills, NC Station Number of Clasts Corner Coordinates Sediment ≥ 1 Inch Shell ≥ 3 Inch x y 209+74 9 35 1 2981706.4 853775.9 2 2981741.2 853719.9 3 2981596.0 853634.7 4 2981563.7 853685.6 235+00 0 14 1 2982944.3 851642.1 2 2982985.7 851576.6 3 2982877.6 851503.4 4 2982834.9 851574.6 260+17 0 17 1 2984343.4 849438.9 2 2984357.6 849391.8 3 2984171.5 849296.6 4 2984149.7 849336.6 289+99 0 2 1 2985778.3 846832.7 2 2985810.5 846773.5 3 2985694.6 846712.2 4 2985657.4 846770.6 320+05 0 25 1 2987274.2 844234.3 2 2987325.4 844169.3 3 2987215.1 844114.7 4 2987178.3 844182.8 APPENDIX 4 DIGITAL FILES (Digital Copy Only) • Shapefiles of the survey areas • Excel file with data for client • Project photos