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HomeMy WebLinkAboutCurrituck RCCP Phase 3 Report Final WithersRavenel 115 MacKenan Drive Cary, NC 27511 Currituck RCCP Phase 3 DESIGN REPORT February 2024 WR Job Number: 23-0292 Amanda Hollingsworth, PE Katherine Knight, PE 2/22/2024 RCCP Phase 3 Design Report Currituck County WR No. 23-0292 i February 2024 Table of Contents Introduction ....................................................................................................................................................... 3 Hydrologic and Hydraulic Modeling ............................................................................................................ 4 Spatially Varying 2D “Rain on Grid” Model................................................................................................. 4 Results ................................................................................................................................................................ 8 Area 1 – Baxter Lane, Parrish Point Lane, and Alden Run ....................................................................... 9 Existing Conditions .......................................................................................................................................... 9 Proposed Improvements .............................................................................................................................. 10 Area 2 – Old Tulls Creek Rd and Rocky Top Rd ...................................................................................... 11 Existing Conditions ........................................................................................................................................ 11 Proposed Improvements .............................................................................................................................. 12 Preliminary Cost Opinions for Proposed Improvements ....................................................................... 13 List of Tables Table 1 – Land Cover Characteristics .......................................................................................................... 5 Table 2 – HEC-RAS Green & Ampt Infiltration Parameters .................................................................... 5 Table 3 – Preliminary Cost Opinions for Budgetary Purposes ............................................................. 13 List of Figures Figure 1 – Project Areas ................................................................................................................................. 3 Figure 2 – Baxter Lane Existing 10-Year End of Storm ........................................................................... 9 Figure 3 – Baxter Lane Proposed 10-Year End of Storm ...................................................................... 10 Figure 4 – Old Tulls Creek Rd Existing 10-Year End of Storm ............................................................. 11 Figure 5 – Old Tulls Creek Proposed 10-Year End of Storm ................................................................ 12 RCCP Phase 3 Design Report Currituck County WR No. 23-0292 ii February 2024 Appendices Appendix 1: Background Information  NOAA Atlas 14 Precipitation Frequency Estimates  FEMA Flood Insurance Rate Map (Map #: 3721802200K)  FEMA Flood Insurance Rate Map (Map #: 3721803200K)  FEMA Flood Insurance Rate Map (Map #: 3721804000K)  Terrain Map  Land Cover Map Appendix 2: Existing Condition Results  Existing Conditions – 10-year Maximum Inundation Map  Existing Conditions – 10-year End of Storm Inundation Map  Existing Conditions – 25-year Maximum Inundation Map Appendix 3: Proposed Conditions Results  Proposed Conditions – 10-year Maximum Inundation Map  Proposed Conditions – 10-year End of Storm Inundation Map  Proposed Conditions – 25-year Maximum Inundation Map Appendix 4: Opinions of Probable Costs  Proposed Improvement Area 1 Cost Opinion  Proposed Improvement Area 2 Cost Opinion Appendix 5: Concept Project Fact Sheets  Area 1 – Baxter Lane Fact Sheet  Area 2 – Old Tulls Creek Road Fact Sheet RCCP Phase 3 Design Report Currituck County WR No. 23-0292 3 February 2024 Introduction Currituck County has contracted WithersRavenel for consulting services to evaluate existing conditions hydrology and hydraulics for the 10- and 25- year storm events and provide preliminary designs to mitigate flooding for two (2) project areas. To achieve these goals, a two-dimensional existing conditions flood model was created to simulate the 10-, and 25-year, 24-hour storm events. The existing conditions model was used to create inundation maps to depict depths and extents of flooding for each simulated storm event. Conceptual level improvements for each area were developed and modeled to mitigate flood conditions and decrease inundation time. Planning level cost opinions were prepared for the proposed improvements. The selected project areas include the primarily residential area bounded by Baxter Lane, Parrish Point Lane and Alden Run and the residential area bounded by Old Tulls Creek Road and Rocky Top Road as seen in Figure 1 below. These areas experience frequent flooding and were identified as areas of concern in the Phase 1 and 2 Resilient Coastal Communities Program (RCCP) report. Figure 1 – Project Areas Area 1 Area 2 RCCP Phase 3 Design Report Currituck County WR No. 23-0292 4 February 2024 Hydrologic and Hydraulic Modeling Spatially Varying 2D “Rain on Grid” Model The United States Army Corps of Engineers (USACE) Hydrologic Engineering Center River Analysis System (HEC-RAS) v. 6.3.1 was utilized for the hydrologic and hydraulic model. HEC-RAS was selected for its two-dimensional (2D) spatially varying precipitation, infiltration, runoff, and flow modeling capabilities. The 2D HEC-RAS model utilized seven (7) basic components: A terrain, precipitation data, a Manning's "n" layer, an infiltration layer, boundary conditions, a 2D mesh, and SA/2D connections. Terrain The HEC-RAS Terrain utilized in the simulation was a 3ft x 3ft (1-meter) DEM generated from 2014 QL2 LiDAR (3-meter resolution) obtained from NC Spatial Data Download. Precipitation Rainfall data was input as 24-hr SCS Type III unit rainfall hyetographs for the 10- and 25- year, 24- hour storm events. Rainfall depths were obtained from NOAA Atlas 14 (See APPENDIX 1). Manning’s n Values The Mannings’s Equation is used within the HEC-RAS model to determine the velocity of surface flows over different land cover types. An important variable within the Manning’s Equation is the Manning’s n-value, a coefficient which represents the roughness or friction applied to the flow of water over a surface. In order to assign appropriate Manning’s n-values, the study area was delineated into varying land cover types. A spatially varying land cover raster was generated utilizing Microsoft’s Planetary Computer Land Cover Mapping platform (PEARL) machine learning model. The United States Geological Survey (USGS) National Agriculture Imagery Program (NAIP) 1-meter resolution imagery was input into the PEARL East Coast NAIP 9 Class pre-trained machine learning model. The result was a raster which discretized land cover into the following 9 classes: water, emergent wetlands, tree, shrubland, low vegetation, barren, structure, impervious surface, and impervious road. A high- resolution roadway vector layer was delineated based on zoning boundaries as well as high- resolution 2020 aerial imagery obtained from NC OneMap. This vector layer was utilized to overwrite the raster values where it intersected to refine the accuracy of roadways within the land cover raster. The open water and land in agricultural production was hand delineated and superimposed onto the land cover raster in the same fashion. Building polygons obtained from NC Spatial Data Download were also superimposed onto the raster to improve the accuracy and resolution of key components within the model. The North Carolina Department of Environmental Quality (NCDEQ) Coastal Region Evaluation of Wetland Significance (CREWS) wetlands data were imposed onto the raster where applicable. Characteristics for the nine (9) unique land use categories that were used to assign Manning’s “n” roughness coefficients and impervious percentages can be seen in TABLE 1. RCCP Phase 3 Design Report Currituck County WR No. 23-0292 5 February 2024 Table 1 – Land Cover Characteristics Classification Manning’s n Impervious Percentage Unclassified 0.00 0% Woods 0.11 0% Open Space 0.06 0% Structure 0.011 100% Impervious Surface 0.011 100% Impervious Road 0.011 100% Agricultural 0.095 0% Wetlands 0.13 0% Water 0.045 100% Infiltration The HEC-RAS model accounts infiltration of rainfall into in-situ soils by removing the anticipated infiltration volume from the rainfall volume applied to each cell of the HEC-RAS Terrain. The infiltration volume at any given location within the model is a component of land cover and underlying soil types. The infiltration layer was computed within HEC-RAS by intersecting the land cover layer with the SSURGO soils layer for Currituck County and Chesapeake, Virginia. Infiltration was calculated using the Green & Ampt method with Redistribution (GAR). Values for wetting suction front, saturated hydraulic conductivity, initial soil water content, saturated soil water content, residual soil water content, and pore size distribution index were derived approximated based on the soil textures obtained from the SSURGO soils layer. Parameter approximations were based on values published by Gowdish and Munoz-Carpena in 2009, Rawls and Brakensiek in 1982, and Rawls et al. in 1983. TABLE 2 below summarizes the values utilized within the HEC-RAS model. The land cover layer was utilized to assign impervious percentage to effect direct runoff across the site. Areas of impervious coverage as well as open water were modeled with a saturated hydraulic conductivity of 0. Table 2 – HEC-RAS Green & Ampt Infiltration Parameters Map Unit Name Wetting Suction Front (in) Saturated Hydraulic Conductivity (in/hr) Field Capacity Total Porosity Residual Soil Water Content Pore Size Distribution Index Chapanoke- Yeopim complex 6.57 0.26 0.133 0.486 0.015 0.234 Water 0 0 0 0 0 0 Dorovan- Belhaven complex 2.41 1.18 0.055 0.402 0.035 0.553 RCCP Phase 3 Design Report Currituck County WR No. 23-0292 6 February 2024 Acredale silt loam 6.57 0.26 0.133 0.486 0.015 0.234 Tomotley-Deloss complex 4.33 0.43 0.095 0.412 0.041 0.378 Nawney silt loam 6.57 0.26 0.133 0.486 0.015 0.234 Tomotley-Bertie complex 4.33 0.43 0.095 0.412 0.041 0.378 Acredale- Chapanoke complex 6.57 0.26 0.133 0.486 0.015 0.234 Tomotley- Nimmo complex 4.33 0.43 0.095 0.412 0.041 0.378 Pocaty mucky peat 6.57 0.26 0.133 0.486 0.015 0.234 Tetotum fine sandy loam 4.33 0.43 0.095 0.412 0.041 0.378 Chesapeake sandy loam 4.33 0.43 0.095 0.412 0.041 0.378 Udorthents- Urban land complex 0 0 0 0 0 0 Tomotley fine sandy loam 4.33 0.43 0.095 0.412 0.041 0.378 Roanoke fine sandy loam 6.57 0.26 0.133 0.486 0.015 0.234 Wahee fine sandy loam 4.33 0.43 0.095 0.412 0.041 0.378 Augusta fine sandy loam 4.33 0.43 0.095 0.412 0.041 0.378 State fine sandy loam 4.33 0.43 0.095 0.412 0.041 0.378 Currituck mucky peat 1.95 4.64 0.033 0.417 0.02 0.694 Conaby muck 1.95 4.64 0.033 0.417 0.02 0.694 Water 0 0 0 0 0 0 Dorovan mucky peat 2.41 1.18 0.055 0.402 0.035 0.553 Pasquotank silt loam 6.57 0.26 0.133 0.486 0.015 0.234 Portsmouth fine sandy loam 4.33 0.43 0.095 0.412 0.041 0.378 Tomotley fine sandy loam 4.33 0.43 0.095 0.412 0.041 0.378 Altavista fine sandy loam 4.33 0.43 0.095 0.412 0.041 0.378 RCCP Phase 3 Design Report Currituck County WR No. 23-0292 7 February 2024 Munden fine sandy loam 4.33 0.43 0.095 0.412 0.041 0.378 Dragston loamy fine sand 2.41 1.18 0.055 0.402 0.035 0.553 2D Computational Mesh The 2D computational mesh, also known as the 2D flow area, is a network of interconnected cells used to represent the two-dimensional flow characteristics of the model area. Each cell and associated cell face of the computational mesh is pre-processed to compute detailed hydraulic property tables based on the underlying terrain. For each cell, the pre-processor computes an elevation vs. volume relationship. For each cell face, which can be thought of as detailed 1D cross sections, the pre-processor computes elevation vs. wetted perimeter, roughness, area, etc. The flow of water between each cell is controlled by these detailed hydraulic property tables which are used in calculating water surface elevation, depth, velocity, etc. This modeling technique is commonly referred to as a “subgrid model” and allows HEC-RAS to determine preferential flow paths in the underlying terrain and wet only a portion of the cell below the computed water surface elevation at that time step. The “subgrid model” associated with the 2D computational mesh allows for detailed analysis of the project area where accurate overland flow pathways are paramount for model accuracy. In addition, breaklines, which allow for portions of higher cell resolution and specific directional orientation, were utilized to increase model resolution and accuracy. Breaklines were added to ditch centerlines, stream centerlines, stream banks, road curbs, road crests, and significant topographic features. With this detailed information, the HEC-RAS model was able to represent the complex flow dynamics across the project area. SA/2D Connections SA/2D connections allow for storage areas and 2D flow areas to be hydraulically linked in various combinations. These links are represented by several types of hydraulic structures including weirs, gates, culverts, and rating curves. SA/2D connections can also be placed within a 2D flow area to control flow between one cell to another. For example, an SA/2D connection can be used to represent a roadway as an irregular weir, with station and elevation data pulled along the centerline using the specified terrain surface, and a culvert to control flow of water from one side of the road to the other. SA/2D connections were used to model stormwater infrastructure, including cross pipes and roadway culverts. Generally, driveway culverts were not modeled. This was done to reduce processing time due to the large number of SA/2D connections that would be dedicated to driveway culverts which are of lesser concern compared to storm networks and roadway culverts and their potential impacts when inundated. The HEC-RAS model performed 2D unsteady flow routing utilizing the Shallow Water Equations Eulerian-Lagrangian Method (SWE-ELM). The SWE-ELM was the selected equation set to account for the exceptionally flat terrain across the project area, as well as the presence of buildings within RCCP Phase 3 Design Report Currituck County WR No. 23-0292 8 February 2024 the flow paths. A computational time step of 1 second was selected for the simulation runs to maintain numerical accuracy and model stability while avoiding excessive computation time. Boundary Conditions Boundary conditions represent locations in the model where water can flow in or out. HEC-RAS allows a boundary condition to be applied externally (along 2D flow area perimeter), internally (within the 2D flow area), or globally (applied to the entire 2D flow area). There are several boundary condition options that can be applied depending on the type used including flow hydrograph, stage hydrograph, normal depth, rating curve, and precipitation. The following boundary conditions were used in the 2D HEC-RAS model of the project area:  Upstream Boundary Conditions: o Rainfall over model area  Precipitation  Downstream Boundary Conditions o Currituck Sound  Stage Hydrograph/Normal Depth Stage hydrographs were utilized for the downstream boundary condition along the Sound and tributary streams, immediately downstream of the project areas. Stage hydrographs were set to a constant water surface elevation based on detailed flood elevation data provided in the FEMA effective model. In the 10-year event for the Baxter Lane area flood elevations were lower than existing grade elevations so Normal Depth was utilized as the downstream boundary condition. Results After model validation, the results were analyzed based on flood extents and depth. Flood inundation rasters were generated to create existing conditions flood inundation maps to assess impacted structures, roadways, and infrastructure. Existing conditions flood inundation maps for each design storm can be found in APPENDIX 4. RCCP Phase 3 Design Report Currituck County WR No. 23-0292 9 February 2024 Area 1 – Baxter Lane, Parrish Point Lane, and Alden Run Existing Conditions The maximum flooding extents across the Baxter Lane modeled area fully cover agricultural fields and yards with most flooding subsiding by the end of the storm event. In the 10-year storm event there is yard flooding remaining at the properties along Baxter Lane even at the end of the storm event. The eastern end of Baxter Lane is inundated in the 25-year storm event. The Baxter Lane area has historically been drained through a series of agricultural ditches as well as roadside ditches along Baxter Lane and with two 24” cross pipes to provide drainage from the minor ditch on the north side of the road to the major ditch located to the south. Two developments have been constructed along Baxter Lane, Windswept Pines and Baxter Station, which have modified the agricultural ditches on their sites, including widening the major roadside ditch in front of Baxter Station and the installation of triple 36” cross pipes under Baxter Lane from Windswept Pines. Due to the generally flat topography yard flooding does not always runoff in a uniform direction and it is believed that the yard flooding at Baxter Lane is primarily the result of drainage ditches without uniform slope to provide positive drainage and conveyance away from the properties and the lack of drainage ditches to collect runoff in some low lying areas. Figure 2 – Baxter Lane Existing 10-Year End of Storm RCCP Phase 3 Design Report Currituck County WR No. 23-0292 10 February 2024 Proposed Improvements Due to the duration of flooding and number of properties impacted, the area on the north side of Baxter Lane was selected as the project area. The proposed concept includes installation of a drainage ditch to collect runoff at the back of the properties and convey it to the major ditch along Baxter Lane. To achieve this 2,760 LF of a 6’ bottom width drainage ditch is proposed to be constructed beginning at the back of 167 Baxter Lane and running along the back of properties to 114 Cedar Lane before turning south to follow the existing drainage to Baxter Lane. At Baxter Lane an additional 24” cross pipe would be installed. Additionally, the existing culvert at the east end of Baxter Lane is proposed to be upsized as a condition of another development occurring in the vicinity. The proposed concept allows for drainage of runoff currently pooling at the back of the properties along Baxter Lane. The proposed drainage ditch is located on private property and will require cooperation with property owners. Additional property owner maintenance and improvement of lot line ditches would maximize the impact of the project. It is also recommended to continue the widened section of the roadside ditch south of Baxter Lane from the Baxter Station development to the outfall to improve hydraulic capacity throughout. Figure 3 – Baxter Lane Proposed 10-Year End of Storm RCCP Phase 3 Design Report Currituck County WR No. 23-0292 11 February 2024 Area 2 – Old Tulls Creek Rd and Rocky Top Rd Existing Conditions The maximum flooding extents across the Old Tulls Creek Road and Rocky Top Road area includes shallow (less than 3”) flooding across agricultural fields in both the 10-year and 25-year storm events, partial inundation of Matilda Terrace in the 25-year storm event, significant (greater than 12”) yard flooding along Old Tulls Creek Road and inundation of Old Tulls Creek Road in both the 10-year and 25-year storm events. There is a natural drainage through the front yards along Old Tulls Creek Road that is the primary source of flooding along this stretch. Driveways obstruct flow and due to the low lying nature of the topography of this draw, flood water from Tull Bay inundates the area in significant storm events. Figure 4 – Old Tulls Creek Rd Existing 10-Year End of Storm RCCP Phase 3 Design Report Currituck County WR No. 23-0292 12 February 2024 Proposed Improvements Due to the depth of flooding and number of properties impacted, the area along Old Tulls Creek Road was selected as the project area. The proposed concept includes rerouting runoff from upstream to bypass the existing drainage in the front yard of the properties along Old Tulls Creek. To achieve this, a berm set at elevation 5.0 will be constructed northwest of 106 Old Tulls Creek Road to divert flows and 1,500 LF of a 14’ bottom width drainage ditch will be installed to carry the diverted flows around the back of the properties along Old Tulls Creek Road and discharge to the natural drainage southeast of 126 Old Tulls Creek Road. The proposed concept reduces the inundated yard area as well as reduces inundation of the road to less than 2” in the 10-year storm event. The proposed improvement is located entirely on private property and will require cooperation with property owners and recommended property owner education on the importance of maintenance of all drainages and keeping ditches and culverts clear and functioning. Figure 5 – Old Tulls Creek Proposed 10-Year End of Storm RCCP Phase 3 Design Report Currituck County WR No. 23-0292 13 February 2024 Preliminary Cost Opinions for Proposed Improvements Preliminary cost opinions were developed for each proposed improvement area to assist with planning and prioritization. The cost opinions were based on installation and replacement of stormwater infrastructure quantities only; costs for engineering design, survey, and construction labor were based off a percentage of the stormwater infrastructure material costs. Additional costs associated with permitting, land or easement acquisition, utility relocation, or additional improvements were not considered. These cost opinions are based on current pricing as of the date of this report and do not consider cost increases due to inflation. See APPENDIX 4 for a more detailed breakdown of cost opinions for each area of concern. The following table summarizes the preliminary cost opinions for each area of concern described above: Table 3 – Preliminary Cost Opinions for Budgetary Purposes Proposed Improvement Area Probable Cost Improvement Area #1 $ 419,320 Improvement Area #2 $ 386,320 RCCP Phase 3 Design Report Currituck County WR No. 23-0292 February 2024 Appendix 1: Background Information  NOAA Atlas 14 Precipitation Frequency Estimates  FEMA Flood Insurance Rate Map (Map #: 3721802200K)  FEMA Flood Insurance Rate Map (Map #: 3721803200K)  FEMA Flood Insurance Rate Map (Map #: 3721804000K)  Terrain Map  Land Cover Map 9/5/23, 3:30 PM Precipitation Frequency Data Server https://hdsc.nws.noaa.gov/pfds/pfds_printpage.html?lat=36.5047&lon=-76.1015&data=depth&units=english&series=pds 1/4 NOAA Atlas 14, Volume 2, Version 3 Location name: Moyock, North Carolina, USA* Latitude: 36.5047°, Longitude: -76.1015° Elevation: 7 ft** * source: ESRI Maps ** source: USGS POINT PRECIPITATION FREQUENCY ESTIMATES G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley NOAA, National Weather Service, Silver Spring, Maryland PF_tabular | PF_graphical | Maps_&_aerials PF tabular PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1 Duration Average recurrence interval (years) 1 2 5 10 25 50 100 200 500 1000 5-min 0.434 (0.393‑0.478) 0.505 (0.456‑0.559) 0.565 (0.511‑0.626) 0.653 (0.588‑0.723) 0.735 (0.659‑0.812) 0.812 (0.726‑0.897) 0.880 (0.784‑0.973) 0.946 (0.838‑1.05) 1.02 (0.900‑1.14) 1.10 (0.963‑1.22) 10-min 0.693 (0.629‑0.764) 0.807 (0.729‑0.894) 0.905 (0.819‑1.00) 1.04 (0.940‑1.16) 1.17 (1.05‑1.30) 1.29 (1.16‑1.43) 1.40 (1.24‑1.55) 1.50 (1.33‑1.66) 1.62 (1.42‑1.80) 1.74 (1.52‑1.93) 15-min 0.866 (0.786‑0.955) 1.01 (0.917‑1.12) 1.14 (1.04‑1.27) 1.32 (1.19‑1.46) 1.48 (1.33‑1.64) 1.64 (1.46‑1.81) 1.77 (1.57‑1.95) 1.89 (1.68‑2.09) 2.04 (1.79‑2.26) 2.18 (1.90‑2.42) 30-min 1.19 (1.08‑1.31) 1.40 (1.27‑1.55) 1.63 (1.47‑1.80) 1.91 (1.72‑2.12) 2.20 (1.97‑2.43) 2.47 (2.20‑2.72) 2.71 (2.41‑2.99) 2.95 (2.61‑3.26) 3.25 (2.85‑3.60) 3.54 (3.08‑3.92) 60-min 1.48 (1.34‑1.63) 1.76 (1.59‑1.95) 2.08 (1.89‑2.31) 2.49 (2.24‑2.76) 2.93 (2.63‑3.24) 3.34 (2.99‑3.69) 3.73 (3.32‑4.12) 4.13 (3.66‑4.57) 4.66 (4.09‑5.16) 5.16 (4.50‑5.73) 2-hr 1.74 (1.57‑1.93) 2.07 (1.86‑2.31) 2.50 (2.24‑2.79) 3.04 (2.72‑3.38) 3.64 (3.25‑4.04) 4.24 (3.76‑4.70) 4.80 (4.24‑5.33) 5.41 (4.75‑6.00) 6.22 (5.41‑6.90) 7.00 (6.04‑7.77) 3-hr 1.86 (1.68‑2.08) 2.22 (1.99‑2.48) 2.69 (2.41‑3.01) 3.29 (2.94‑3.68) 3.98 (3.54‑4.44) 4.68 (4.13‑5.20) 5.36 (4.71‑5.96) 6.10 (5.32‑6.78) 7.11 (6.14‑7.90) 8.11 (6.93‑9.01) 6-hr 2.22 (2.00‑2.48) 2.64 (2.37‑2.96) 3.20 (2.87‑3.59) 3.92 (3.50‑4.39) 4.77 (4.23‑5.32) 5.62 (4.96‑6.25) 6.46 (5.67‑7.18) 7.39 (6.42‑8.20) 8.66 (7.44‑9.61) 9.93 (8.43‑11.0) 12-hr 2.61 (2.35‑2.93) 3.10 (2.77‑3.50) 3.78 (3.37‑4.25) 4.65 (4.14‑5.23) 5.70 (5.03‑6.38) 6.77 (5.93‑7.56) 7.84 (6.82‑8.74) 9.04 (7.77‑10.1) 10.7 (9.06‑11.9) 12.4 (10.3‑13.7) 24-hr 3.05 (2.80‑3.35) 3.71 (3.41‑4.08) 4.79 (4.39‑5.26) 5.70 (5.20‑6.24) 7.05 (6.39‑7.70) 8.20 (7.38‑8.96) 9.47 (8.43‑10.3) 10.9 (9.58‑11.9) 12.9 (11.2‑14.2) 14.7 (12.6‑16.2) 2-day 3.54 (3.25‑3.88) 4.29 (3.94‑4.70) 5.50 (5.05‑6.02) 6.54 (5.99‑7.15) 8.11 (7.36‑8.84) 9.47 (8.51‑10.3) 11.0 (9.77‑12.0) 12.7 (11.1‑13.8) 15.2 (13.1‑16.7) 17.4 (14.7‑19.2) 3-day 3.76 (3.47‑4.10) 4.55 (4.21‑4.97) 5.82 (5.37‑6.34) 6.89 (6.33‑7.49) 8.47 (7.71‑9.19) 9.81 (8.87‑10.6) 11.3 (10.1‑12.3) 12.9 (11.4‑14.1) 15.4 (13.3‑16.8) 17.5 (15.0‑19.3) 4-day 3.98 (3.69‑4.32) 4.82 (4.47‑5.24) 6.14 (5.68‑6.66) 7.23 (6.67‑7.83) 8.82 (8.07‑9.54) 10.2 (9.23‑11.0) 11.6 (10.5‑12.6) 13.2 (11.7‑14.3) 15.5 (13.6‑16.9) 17.7 (15.3‑19.4) 7-day 4.65 (4.33‑5.04) 5.61 (5.23‑6.08) 7.05 (6.55‑7.62) 8.24 (7.63‑8.89) 9.95 (9.16‑10.7) 11.4 (10.4‑12.3) 12.9 (11.7‑13.9) 14.6 (13.1‑15.8) 16.9 (15.0‑18.4) 18.9 (16.5‑20.7) 10-day 5.26 (4.92‑5.64) 6.31 (5.90‑6.76) 7.81 (7.30‑8.37) 9.06 (8.44‑9.69) 10.8 (10.0‑11.6) 12.3 (11.3‑13.2) 13.9 (12.7‑14.9) 15.6 (14.1‑16.8) 18.0 (16.0‑19.5) 20.0 (17.6‑21.7) 20-day 7.15 (6.72‑7.62) 8.51 (8.00‑9.08) 10.3 (9.72‑11.0) 11.8 (11.1‑12.6) 14.0 (13.0‑14.9) 15.7 (14.6‑16.8) 17.5 (16.1‑18.8) 19.5 (17.7‑20.9) 22.2 (19.9‑23.9) 24.4 (21.7‑26.4) 30-day 8.81 (8.31‑9.36) 10.5 (9.88‑11.1) 12.6 (11.9‑13.4) 14.3 (13.4‑15.2) 16.6 (15.6‑17.7) 18.5 (17.2‑19.7) 20.4 (18.9‑21.7) 22.4 (20.6‑23.9) 25.0 (22.8‑26.9) 27.1 (24.5‑29.3) 45-day 10.9 (10.3‑11.6) 12.9 (12.2‑13.7) 15.4 (14.6‑16.4) 17.5 (16.5‑18.6) 20.4 (19.1‑21.7) 22.8 (21.2‑24.2) 25.2 (23.3‑26.8) 27.7 (25.5‑29.6) 31.3 (28.4‑33.5) 34.1 (30.7‑36.7) 60-day 13.1 (12.4‑13.9) 15.5 (14.6‑16.4) 18.3 (17.3‑19.3) 20.5 (19.3‑21.7) 23.5 (22.1‑24.9) 25.9 (24.3‑27.5) 28.4 (26.4‑30.1) 30.8 (28.6‑32.8) 34.2 (31.4‑36.5) 36.7 (33.4‑39.5) 1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values. Please refer to NOAA Atlas 14 document for more information. Back to Top PF graphical 9/5/23, 3:30 PM Precipitation Frequency Data Server https://hdsc.nws.noaa.gov/pfds/pfds_printpage.html?lat=36.5047&lon=-76.1015&data=depth&units=english&series=pds 2/4 Back to Top Maps & aerials Small scale terrain 9/5/23, 3:30 PM Precipitation Frequency Data Server https://hdsc.nws.noaa.gov/pfds/pfds_printpage.html?lat=36.5047&lon=-76.1015&data=depth&units=english&series=pds 3/4 Large scale terrain Large scale map Large scale aerial + – 3km 2mi + – 100km 60mi + – 100km 60mi 9/5/23, 3:30 PM Precipitation Frequency Data Server https://hdsc.nws.noaa.gov/pfds/pfds_printpage.html?lat=36.5047&lon=-76.1015&data=depth&units=english&series=pds 4/4 Back to Top US Department of Commerce National Oceanic and Atmospheric Administration National Weather Service National Water Center 1325 East West Highway Silver Spring, MD 20910 Questions?: HDSC.Questions@noaa.gov Disclaimer + – 100km 60mi FLOOD HAZARD INFORMATION SPECIAL FLOODHAZARD AREAS OTHER AREAS OFFLOOD HAZARD OTHERAREAS GENERALSTRUCTURES Without Base Flood Elevation (BFE) With BFE or Depth Regulatory Floodway Areas Determined to be Outside the 0.2% Annual Chance Floodplain Non-accredited Levee, Dike, or Floodwall Zone A,V, A99 Zone AE, AO, AH, VE, AR Zone X HTTP://FRIS.NC.GOV/FRIS THE INFORMATION DEPICTED ON THIS MAP AND SUPPORTINGDOCUMENTATION ARE ALSO AVAILABLE IN DIGITAL FORMAT AT NORTH CAROLINA FLOODPLAIN MAPPING PROGRAM FLOOD INSURANCE RATE MAPNORTH CAROLINA PANEL SEE FIS REPORT FOR ZONE DESCRIPTIONS AND INDEX MAP Cross Sections with 1% Annual ChanceWater Surface Elevation (BFE) Coastal Transect OTHERFEATURES Profile Baseline Hydrographic Feature Limit of Study Limit of Moderate Wave Action (LiMWA) Jurisdiction Boundary Accredited or Provisionally AccreditedLevee, Dike, or Floodwall Coastal Transect Baseline SCALE 1 inch = 1,000 feet Map Projection:North Carolina State Plane Projection Feet (Zone 3200)Datum: NAD 1983 (Horizontal), NAVD 1988 (Vertical) PANEL LOCATOR LOGO LOGO NOTES TO USERS For information and questions about this map, available products associated with this FIRM including historic versions of this FIRM, how to order products or the National Flood Insurance Program in general,please call the FEMA Map Information eXchange at 1-877-FEMA-MAP (1-877-336-2627) or visit the FEMA Map Service Center website at https://msc.fema.gov. An accompanying Flood Insurance Study report, Letter of Map Revision (LOMR) or Letter of Map Amendment (LOMA) revising portions of this panel, and digital versions of this FIRM may be available. Visit the North Carolina Floodplain Mapping Program website at http://www.ncfloodmaps.com, or contact the FEMA Map Service Center. Communities annexing land on adjacent FIRM panels must obtain a current copy of the adjacent panel as well asthe current FIRM Index. These may be ordered directly from the Map Service Center at the number listed above. For community and countywide map dates refer to the Flood Insurance Study report for this jurisdiction. To determine if flood insurance is available in the community, contact your Insurance agent or call the NationalFlood Insurance Program at 1-800-638-6620. Flood Insurance Study (FIS) means an examination, evaluation, and determination of flood hazards, correspondingwater surface elevations, flood hazard risk zones, and other flood data in a community issued by the North CarolinaFloodplain Mapping Program (NCFMP). The Flood Insurance Study (FIS) is comprised of the following productsused together: the Digital Flood Hazard Database, the Water Surface Elevation Rasters, the digitally derived,autogenerated Flood Insurance Rate Map and the Flood Insurance Survey Report. A Flood Insurance Survey is acompilation and presentation of flood risk data for specific watercourses, lakes, and coastal flood hazard areas withina community. This report contains detailed flood elevation data, data tables and FIRM indices. When a flood study iscompleted for the NFIP, the digital information, reports and maps are assembled into an FIS. Information shown onthis FIRM is provided in digital format by the NCFMP. Base map information shown on this FIRM was provided indigital format by the NCFMP. The source of this information can be determined from the metadata available in thedigital FLOOD database and in the Technical Support Data Notebook (TSDN). ACCREDITED LEVEE NOTES TO USERS: If an accredited levee note appears on this panel check with your local community to obtain more information, such as the estimated level of protection provided (which may exceed the 1-percent-annual-chance level) and Emergency Action Plan, on the levee system(s) shown as providing protection. To mitigate flood risk in residual risk areas, property owners and residents are encouraged to consider flood insurance and floodproofing or other protective measures. For more information on flood insurance, interested parties should visit the FEMA Website at https://www.fema.gov/national-flood-insurance-program. PROVISIONALLY ACCREDITED LEVEE NOTES TO USERS: If a Provisionally Accredited Levee (PAL) note appears on this panel, check with your local community to obtain more information, such as the estimated level of protection provided (which may exceed the 1-percent-annual-chance level) and Emergency Action Plan, on the levee system(s) shown as providing protection. To maintain accreditation, the levee owner or community is required to submit the data and documentation necessary to comply with Section 65.10 of the NFIP regulations.If the community or owner does not provide the necessary data and documentation or if the data and documentation provided indicates the levee system does not comply with Section 65.10 requirements, FEMA will revise the flood hazard and risk information for this area to reflect de-accreditation of the levee system. To mitigate flood risk in residual risk areas, property owners and residents are encouraged to consider flood insurance and floodproofing or other protective measures. For more information on flood insurance, interested parties should visit the FEMA Website at https://www.fema.gov/national-flood-insurance-program. LIMIT OF MODERATE WAVE ACTION NOTES TO USERS: For some coastal flooding zones the AE Zonecategory has been divided by a Limit of Moderate Wave Action (LiMWA). The LiMWA represents the approximatelandward limit of the 1.5-foot breaking wave. The effects of wave hazards between the VE Zone and the LiMWA(or between the shoreline and the LiMWA for areas where VE Zones are not identified) will be similar to, but lesssevere than those in the VE Zone. COASTAL BARRIER RESOURCES SYSTEM (CBRS) NOTE This map may include approximate boundaries of the CBRS for informational purposes only. Flood insurance is notavailable within CBRS areas for structures that are newly built or substantially improved on or after the date(s)indicated on the map. For more information see http://www.fws.gov/cbra, the FIS Report, or call the U.S. Fishand Wildlife Service Customer Service Center at 1-800-344-WILD. CBRS Area Otherwise Protected Area Channel, Culvert, or Storm Sewer 0.2% Annual Chance Flood Hazard, Areas of 1% Annual Chance Flood with Average Depth Less Than One Foot or With Drainage Areas of Less Than One Square MileFuture Conditions 1% Annual Chance Flood HazardArea with Reduced Flood Risk due to LeveeSee Notes Zone X Zone X Zone X 8040 1:12,000 %,012 18.2 !(8 2840000 FEET1000000 FEET 2840000 FEET1020000 FEET 2860000 FEET 1020000 FEET 2860000 FEET 1000000 FEET This digital Flood Insurance Rate Map (FIRM) was produced through a uniquecooperative partnership between the State of North Carolina and the FederalEmergency Management Agency (FEMA). The State of North Carolina hasimplemented a long term approach to floodplain management to decrease thecosts associated with flooding. This is demonstrated by the State's commitmentto map flood hazard areas at the local level. As a part of this effort, the State ofNorth Carolina has joined in a Cooperating Technical State agreement withFEMA to produce and maintain this digital FIRM. NATIONAL FLOOD INSURANCE PROGRAM ? ? ? ? ? ? ? ? ? ? ? ? T u l l s C r e e k R d Merc e r D r SailfishSt Row l a n d C r e e k R d Rocky Top Rd Franklin Ln Dolphin St W renDr Meadow B l u e Chip Dr Geo r g e Dr Th a y n e D r R a n c hla n d D r D urbins Ln Perc h S t Marlin St Sno w den R d Flou n d e r St Trout S t Shar k S t Dru m m St Bass St Vincent Dr Porp o i s e St Pike S t Caro l i n a R d Barr a c u d a St Mun d e n L n La m b D r Cobi a S t Chic k a d e e St CampusDr Croa k e r S t C o w b o y T r l R a n c h l a n d T r l BisonDr Our S t Elrod Rd SpurTrl Creek Dr Ferrell M i l l R d Speckleperch Ln Big Bend Dr Deer R u n Pinto Dr WindchaserWay Ha s t i n g s D r GuineaMillRd BeechwoodShoresDr W il d w o o d F a r m s A v e Matildas Trace GuineaRd Spr u i l l Ln Old TullsCreek Rd P o y n e r s R d St o n e S t Old J u r y R d River Rd Carat o k e H w y CURRITUCK COUNTYUNINCORPORATED AREAS370078 ZONE AE(EL 5) ZONE AE(EL 4) ZONE AE(EL 4) ZONE AE(EL 4) ZONE AE(EL 4) ZONE AE(EL 4) ZONE AE(EL 4) ¬«10 ¬«13 ¬«10 FX0572 FX0573 FX2341 FX2342 FX2344 FX3687 FX4471 FX4525 FX4817 FX2343 ¬«3 ¬«12 ¬«9 ¬«6 ¬«7 ¬«8 76°4'30"W 76°5'0"W 76°5'0"W 76°5'30"W 76°5'30"W 76°6'0"W 76°6'0"W 76°6'30"W 76°6'30"W 76°7'0"W 76°7'0"W 76°7'30"W 76°7'30"W 76°8'0"W 76°8'0"W 76°8'30"W 36°31'0"N 36°31'0"N 36°30'30"N 36°30'30"N 36°30'0"N 36°30'0"N 36°29'30"N 36°29'30"N 36°29'0"N 36°29'0"N 36°28'30"N 36°28'30"N 36°28'0"N 36°28'0"N Currituck Camden Pasquotank Perquimans Dare Tyrrell 7082 8003 8013 8023 8033 8042 8062 8082 9003 9013 9023 8002 8012 8022 8032 9002 9012 9022 7091 8001 8011 8021 8031 8040 8060 8081 8091 9001 9011 9021 8010 8020 8030 8080 8090 9000 9010 9020 8928 8948 8968 8989 8999 9909 9919 9929 9939 9819 9829 8988 8998 9908 9918 9928 9938 8926 8946 8966 8986 9906 9927 9937 9926 9936 8944 8964 8984 9904 9925 9935 9945 9924 9934 9944 8982 9902 9923 9933 9943 9922 9932 9942 9952 9900 9921 9931 9941 9951 9920 9930 9940 9839 9849 9818 9828 9838 9848 9858 9806 9827 9837 9847 9857 9826 9836 9846 9856 9804 9824 9844 I 0 1,000 2,000500Feet 0 300 600150Meters BM5510 D North Carolina Geodetic Survey bench mark BM5510 ?BM5510z National Geodetic Survey bench markContractor Est. NCFMP Survey bench mark Panel Contains: COMMUNITY CID PANEL SUFFIX 8040370078 KCURRITUCK COUNTY VERSION NUMBER2.3.3.2 MAP NUMBER 3721804000K MAP REVISED December 21, 2018 FLOOD HAZARD INFORMATION SPECIAL FLOODHAZARD AREAS OTHER AREAS OFFLOOD HAZARD OTHERAREAS GENERALSTRUCTURES Without Base Flood Elevation (BFE) With BFE or Depth Regulatory Floodway Areas Determined to be Outside the 0.2% Annual Chance Floodplain Non-accredited Levee, Dike, or Floodwall Zone A,V, A99 Zone AE, AO, AH, VE, AR Zone X HTTP://FRIS.NC.GOV/FRIS THE INFORMATION DEPICTED ON THIS MAP AND SUPPORTINGDOCUMENTATION ARE ALSO AVAILABLE IN DIGITAL FORMAT AT NORTH CAROLINA FLOODPLAIN MAPPING PROGRAM FLOOD INSURANCE RATE MAPNORTH CAROLINA PANEL SEE FIS REPORT FOR ZONE DESCRIPTIONS AND INDEX MAP Cross Sections with 1% Annual ChanceWater Surface Elevation (BFE) Coastal Transect OTHERFEATURES Profile Baseline Hydrographic Feature Limit of Study Limit of Moderate Wave Action (LiMWA) Jurisdiction Boundary Accredited or Provisionally AccreditedLevee, Dike, or Floodwall Coastal Transect Baseline SCALE 1 inch = 500 feet Map Projection:North Carolina State Plane Projection Feet (Zone 3200)Datum: NAD 1983 (Horizontal), NAVD 1988 (Vertical) PANEL LOCATOR LOGO LOGO NOTES TO USERS For information and questions about this map, available products associated with this FIRM including historic versions of this FIRM, how to order products or the National Flood Insurance Program in general,please call the FEMA Map Information eXchange at 1-877-FEMA-MAP (1-877-336-2627) or visit the FEMA Map Service Center website at https://msc.fema.gov. An accompanying Flood Insurance Study report, Letter of Map Revision (LOMR) or Letter of Map Amendment (LOMA) revising portions of this panel, and digital versions of this FIRM may be available. Visit the North Carolina Floodplain Mapping Program website at http://www.ncfloodmaps.com, or contact the FEMA Map Service Center. Communities annexing land on adjacent FIRM panels must obtain a current copy of the adjacent panel as well asthe current FIRM Index. These may be ordered directly from the Map Service Center at the number listed above. For community and countywide map dates refer to the Flood Insurance Study report for this jurisdiction. To determine if flood insurance is available in the community, contact your Insurance agent or call the NationalFlood Insurance Program at 1-800-638-6620. Flood Insurance Study (FIS) means an examination, evaluation, and determination of flood hazards, correspondingwater surface elevations, flood hazard risk zones, and other flood data in a community issued by the North CarolinaFloodplain Mapping Program (NCFMP). The Flood Insurance Study (FIS) is comprised of the following productsused together: the Digital Flood Hazard Database, the Water Surface Elevation Rasters, the digitally derived,autogenerated Flood Insurance Rate Map and the Flood Insurance Survey Report. A Flood Insurance Survey is acompilation and presentation of flood risk data for specific watercourses, lakes, and coastal flood hazard areas withina community. This report contains detailed flood elevation data, data tables and FIRM indices. When a flood study iscompleted for the NFIP, the digital information, reports and maps are assembled into an FIS. Information shown onthis FIRM is provided in digital format by the NCFMP. Base map information shown on this FIRM was provided indigital format by the NCFMP. The source of this information can be determined from the metadata available in thedigital FLOOD database and in the Technical Support Data Notebook (TSDN). ACCREDITED LEVEE NOTES TO USERS: If an accredited levee note appears on this panel check with your local community to obtain more information, such as the estimated level of protection provided (which may exceed the 1-percent-annual-chance level) and Emergency Action Plan, on the levee system(s) shown as providing protection. To mitigate flood risk in residual risk areas, property owners and residents are encouraged to consider flood insurance and floodproofing or other protective measures. For more information on flood insurance, interested parties should visit the FEMA Website at https://www.fema.gov/national-flood-insurance-program. PROVISIONALLY ACCREDITED LEVEE NOTES TO USERS: If a Provisionally Accredited Levee (PAL) note appears on this panel, check with your local community to obtain more information, such as the estimated level of protection provided (which may exceed the 1-percent-annual-chance level) and Emergency Action Plan, on the levee system(s) shown as providing protection. To maintain accreditation, the levee owner or community is required to submit the data and documentation necessary to comply with Section 65.10 of the NFIP regulations.If the community or owner does not provide the necessary data and documentation or if the data and documentation provided indicates the levee system does not comply with Section 65.10 requirements, FEMA will revise the flood hazard and risk information for this area to reflect de-accreditation of the levee system. To mitigate flood risk in residual risk areas, property owners and residents are encouraged to consider flood insurance and floodproofing or other protective measures. For more information on flood insurance, interested parties should visit the FEMA Website at https://www.fema.gov/national-flood-insurance-program. LIMIT OF MODERATE WAVE ACTION NOTES TO USERS: For some coastal flooding zones the AE Zonecategory has been divided by a Limit of Moderate Wave Action (LiMWA). The LiMWA represents the approximatelandward limit of the 1.5-foot breaking wave. The effects of wave hazards between the VE Zone and the LiMWA(or between the shoreline and the LiMWA for areas where VE Zones are not identified) will be similar to, but lesssevere than those in the VE Zone. COASTAL BARRIER RESOURCES SYSTEM (CBRS) NOTE This map may include approximate boundaries of the CBRS for informational purposes only. Flood insurance is notavailable within CBRS areas for structures that are newly built or substantially improved on or after the date(s)indicated on the map. For more information see http://www.fws.gov/cbra, the FIS Report, or call the U.S. Fishand Wildlife Service Customer Service Center at 1-800-344-WILD. CBRS Area Otherwise Protected Area Channel, Culvert, or Storm Sewer 0.2% Annual Chance Flood Hazard, Areas of 1% Annual Chance Flood with Average Depth Less Than One Foot or With Drainage Areas of Less Than One Square MileFuture Conditions 1% Annual Chance Flood HazardArea with Reduced Flood Risk due to LeveeSee Notes Zone X Zone X Zone X 8022 1:6,000 %,012 18.2 !(8 2820000 FEET1020000 FEET 2820000 FEET1030000 FEET 2830000 FEET 1030000 FEET 2830000 FEET 1020000 FEET This digital Flood Insurance Rate Map (FIRM) was produced through a uniquecooperative partnership between the State of North Carolina and the FederalEmergency Management Agency (FEMA). The State of North Carolina hasimplemented a long term approach to floodplain management to decrease thecosts associated with flooding. This is demonstrated by the State's commitmentto map flood hazard areas at the local level. As a part of this effort, the State ofNorth Carolina has joined in a Cooperating Technical State agreement withFEMA to produce and maintain this digital FIRM. NATIONAL FLOOD INSURANCE PROGRAM ? ? ? ? ? )) )) )) )) )) )) )) )) 4.9 8.5 4.8 8.6 4.8 4. 0 8.5 4.5 4.2 4.6 4.7 4. 0 4.4 8.6 4.3 8.8 8.6 8.7 9. 5 9. 0 10 . 1 D S t Shi n g l e L a n d i n g R d A St Fo u t z D r RedFish Ln P o i n t H a r b o u r R d Mit c h e l l Ct Winslow Rd PuddinRidgeRd SouthMillsRd C e d a r L n CherrySt L i t t l e A c o r n T r l Camelli a D r Chu r c h S t Jae C t A r r o w H e a d L n Baxter Ln Kat i e s C t S o u t h S t Sou t h LandingDr So u t h M i l l s R d InventorsDr N e w to w n R d Moyock Landing Dr Oa k S t Laz y C o r n e r R d Richard Shaw Rd Fox L n C a r a t o k e H w y < MoyockRun MoyockRun M o y o c k R u n CURRITUCK COUNTYUNINCORPORATED AREAS370078 ZONE AE ZONE AE ZONE AE ZONE AE(EL 4) ¬«6 ¬«5 ¬«4 ¬«6 ¬«5 ¬«4 ,226 ,235 ,181 ,186 ,114 ,118 ,190 ,122 ,126 ,129,133 ,194 ,139 ,142 ,146 ,150 ,153,202 ,207 ,211 ,217 AJ1755 DF5583 DF5584 FX0467 FX2338 76°10'30"W 76°11'0"W 76°11'0"W 76°11'30"W 76°11'30"W 76°12'0"W 76°12'0"W 76°12'30"W 76°12'30"W 36°32'30"N 36°32'30"N 36°32'0"N 36°32'0"N 36°31'30"N 36°31'30"N Currituck Camden Pasquotank Perquimans Dare Tyrrell 7082 8003 8013 8023 8033 8042 8062 8082 9003 9013 9023 8002 8012 8022 8032 9002 9012 9022 7091 8001 8011 8021 8031 8040 8060 8081 8091 9001 9011 9021 8010 8020 8030 8080 8090 9000 9010 9020 8928 8948 8968 8989 8999 9909 9919 9929 9939 9819 9829 8988 8998 9908 9918 9928 9938 8926 8946 8966 8986 9906 9927 9937 9926 9936 8944 8964 8984 9904 9925 9935 9945 9924 9934 9944 8982 9902 9923 9933 9943 9922 9932 9942 9952 9900 9921 9931 9941 9951 9920 9930 9940 9839 9849 9818 9828 9838 9848 9858 9806 9827 9837 9847 9857 9826 9836 9846 9856 9804 9824 9844 I 0 500 1,000250Feet 0 150 30075Meters BM5510 D North Carolina Geodetic Survey bench mark BM5510 ?BM5510z National Geodetic Survey bench markContractor Est. NCFMP Survey bench mark Panel Contains: COMMUNITY CID PANEL SUFFIX 8022370078 KCURRITUCK COUNTY VERSION NUMBER2.3.3.2 MAP NUMBER 3721802200K MAP REVISED December 21, 2018 FLOOD HAZARD INFORMATION SPECIAL FLOODHAZARD AREAS OTHER AREAS OFFLOOD HAZARD OTHERAREAS GENERALSTRUCTURES Without Base Flood Elevation (BFE) With BFE or Depth Regulatory Floodway Areas Determined to be Outside the 0.2% Annual Chance Floodplain Non-accredited Levee, Dike, or Floodwall Zone A,V, A99 Zone AE, AO, AH, VE, AR Zone X HTTP://FRIS.NC.GOV/FRIS THE INFORMATION DEPICTED ON THIS MAP AND SUPPORTINGDOCUMENTATION ARE ALSO AVAILABLE IN DIGITAL FORMAT AT NORTH CAROLINA FLOODPLAIN MAPPING PROGRAM FLOOD INSURANCE RATE MAPNORTH CAROLINA PANEL SEE FIS REPORT FOR ZONE DESCRIPTIONS AND INDEX MAP Cross Sections with 1% Annual ChanceWater Surface Elevation (BFE) Coastal Transect OTHERFEATURES Profile Baseline Hydrographic Feature Limit of Study Limit of Moderate Wave Action (LiMWA) Jurisdiction Boundary Accredited or Provisionally AccreditedLevee, Dike, or Floodwall Coastal Transect Baseline SCALE 1 inch = 500 feet Map Projection:North Carolina State Plane Projection Feet (Zone 3200)Datum: NAD 1983 (Horizontal), NAVD 1988 (Vertical) PANEL LOCATOR LOGO LOGO NOTES TO USERS For information and questions about this map, available products associated with this FIRM including historic versions of this FIRM, how to order products or the National Flood Insurance Program in general,please call the FEMA Map Information eXchange at 1-877-FEMA-MAP (1-877-336-2627) or visit the FEMA Map Service Center website at https://msc.fema.gov. An accompanying Flood Insurance Study report, Letter of Map Revision (LOMR) or Letter of Map Amendment (LOMA) revising portions of this panel, and digital versions of this FIRM may be available. Visit the North Carolina Floodplain Mapping Program website at http://www.ncfloodmaps.com, or contact the FEMA Map Service Center. Communities annexing land on adjacent FIRM panels must obtain a current copy of the adjacent panel as well asthe current FIRM Index. These may be ordered directly from the Map Service Center at the number listed above. For community and countywide map dates refer to the Flood Insurance Study report for this jurisdiction. To determine if flood insurance is available in the community, contact your Insurance agent or call the NationalFlood Insurance Program at 1-800-638-6620. Flood Insurance Study (FIS) means an examination, evaluation, and determination of flood hazards, correspondingwater surface elevations, flood hazard risk zones, and other flood data in a community issued by the North CarolinaFloodplain Mapping Program (NCFMP). The Flood Insurance Study (FIS) is comprised of the following productsused together: the Digital Flood Hazard Database, the Water Surface Elevation Rasters, the digitally derived,autogenerated Flood Insurance Rate Map and the Flood Insurance Survey Report. A Flood Insurance Survey is acompilation and presentation of flood risk data for specific watercourses, lakes, and coastal flood hazard areas withina community. This report contains detailed flood elevation data, data tables and FIRM indices. When a flood study iscompleted for the NFIP, the digital information, reports and maps are assembled into an FIS. Information shown onthis FIRM is provided in digital format by the NCFMP. Base map information shown on this FIRM was provided indigital format by the NCFMP. The source of this information can be determined from the metadata available in thedigital FLOOD database and in the Technical Support Data Notebook (TSDN). ACCREDITED LEVEE NOTES TO USERS: If an accredited levee note appears on this panel check with your local community to obtain more information, such as the estimated level of protection provided (which may exceed the 1-percent-annual-chance level) and Emergency Action Plan, on the levee system(s) shown as providing protection. To mitigate flood risk in residual risk areas, property owners and residents are encouraged to consider flood insurance and floodproofing or other protective measures. For more information on flood insurance, interested parties should visit the FEMA Website at https://www.fema.gov/national-flood-insurance-program. PROVISIONALLY ACCREDITED LEVEE NOTES TO USERS: If a Provisionally Accredited Levee (PAL) note appears on this panel, check with your local community to obtain more information, such as the estimated level of protection provided (which may exceed the 1-percent-annual-chance level) and Emergency Action Plan, on the levee system(s) shown as providing protection. To maintain accreditation, the levee owner or community is required to submit the data and documentation necessary to comply with Section 65.10 of the NFIP regulations.If the community or owner does not provide the necessary data and documentation or if the data and documentation provided indicates the levee system does not comply with Section 65.10 requirements, FEMA will revise the flood hazard and risk information for this area to reflect de-accreditation of the levee system. To mitigate flood risk in residual risk areas, property owners and residents are encouraged to consider flood insurance and floodproofing or other protective measures. For more information on flood insurance, interested parties should visit the FEMA Website at https://www.fema.gov/national-flood-insurance-program. LIMIT OF MODERATE WAVE ACTION NOTES TO USERS: For some coastal flooding zones the AE Zonecategory has been divided by a Limit of Moderate Wave Action (LiMWA). The LiMWA represents the approximatelandward limit of the 1.5-foot breaking wave. The effects of wave hazards between the VE Zone and the LiMWA(or between the shoreline and the LiMWA for areas where VE Zones are not identified) will be similar to, but lesssevere than those in the VE Zone. COASTAL BARRIER RESOURCES SYSTEM (CBRS) NOTE This map may include approximate boundaries of the CBRS for informational purposes only. Flood insurance is notavailable within CBRS areas for structures that are newly built or substantially improved on or after the date(s)indicated on the map. For more information see http://www.fws.gov/cbra, the FIS Report, or call the U.S. Fishand Wildlife Service Customer Service Center at 1-800-344-WILD. CBRS Area Otherwise Protected Area Channel, Culvert, or Storm Sewer 0.2% Annual Chance Flood Hazard, Areas of 1% Annual Chance Flood with Average Depth Less Than One Foot or With Drainage Areas of Less Than One Square MileFuture Conditions 1% Annual Chance Flood HazardArea with Reduced Flood Risk due to LeveeSee Notes Zone X Zone X Zone X 8032 1:6,000 %,012 18.2 !(8 2830000 FEET1020000 FEET 2830000 FEET1030000 FEET 2840000 FEET 1030000 FEET 2840000 FEET 1020000 FEET This digital Flood Insurance Rate Map (FIRM) was produced through a uniquecooperative partnership between the State of North Carolina and the FederalEmergency Management Agency (FEMA). The State of North Carolina hasimplemented a long term approach to floodplain management to decrease thecosts associated with flooding. This is demonstrated by the State's commitmentto map flood hazard areas at the local level. As a part of this effort, the State ofNorth Carolina has joined in a Cooperating Technical State agreement withFEMA to produce and maintain this digital FIRM. NATIONAL FLOOD INSURANCE PROGRAM S a w y e r t o w n R d Marie Ln Creekvie w Cir Fire Stat i o n C t B St Moy o c k L a n d i n g D r Shin g l e L a n d i n g R d Smew Ct N S a w y e r t o w n R d Northwest River D r Tristan Way Goldeneye C t A S t W h is tli ng DuckCt Tulls Cr e e k R d Applewood Dr LittleAcornTrl Baxter Ln MackJones R d CreeksideDr Cypress L a n din g D r S u r f Scoter Loop TabbySt P antherLanding R d Caratoke Hwy < MoyockRun CURRITUCK COUNTYUNINCORPORATED AREAS370078 ZONE AE ZONE AE(EL 4) ZONE AE(EL 4) ZONE AE(EL 4) ZONE AE(EL 4) ZONE AE(EL 4) ¬«4 ¬«5 ¬«6 76°8'30"W 76°8'30"W 76°9'0"W 76°9'0"W 76°9'30"W 76°9'30"W 76°10'0"W 76°10'0"W 76°10'30"W 36°32'30"N 36°32'30"N 36°32'0"N 36°32'0"N 36°31'30"N 36°31'30"N Currituck Camden Pasquotank Perquimans Dare Tyrrell 7082 8003 8013 8023 8033 8042 8062 8082 9003 9013 9023 8002 8012 8022 8032 9002 9012 9022 7091 8001 8011 8021 8031 8040 8060 8081 8091 9001 9011 9021 8010 8020 8030 8080 8090 9000 9010 9020 8928 8948 8968 8989 8999 9909 9919 9929 9939 9819 9829 8988 8998 9908 9918 9928 9938 8926 8946 8966 8986 9906 9927 9937 9926 9936 8944 8964 8984 9904 9925 9935 9945 9924 9934 9944 8982 9902 9923 9933 9943 9922 9932 9942 9952 9900 9921 9931 9941 9951 9920 9930 9940 9839 9849 9818 9828 9838 9848 9858 9806 9827 9837 9847 9857 9826 9836 9846 9856 9804 9824 9844 I 0 500 1,000250Feet 0 150 30075Meters BM5510 D North Carolina Geodetic Survey bench mark BM5510 ?BM5510z National Geodetic Survey bench markContractor Est. NCFMP Survey bench mark Panel Contains: COMMUNITY CID PANEL SUFFIX 8032370078 KCURRITUCK COUNTY VERSION NUMBER2.3.3.2 MAP NUMBER 3721803200K MAP REVISED December 21, 2018 RCCP Phase 3 Design Report Currituck County WR No. 23-0292 February 2024 Appendix 2: Existing Condition Results  Existing Conditions – 10-year Maximum Inundation Map  Existing Conditions – 10-year End of Storm Inundation Map  Existing Conditions – 25-year Maximum Inundation Map RCCP Phase 3 Design Report Currituck County WR No. 23-0292 February 2024 Appendix 3: Proposed Conditions Results  Proposed Conditions – 10-year Maximum Inundation Map  Proposed Conditions – 10-year End of Storm Inundation Map  Proposed Conditions – 25-year Maximum Inundation Map RCCP Phase 3 Design Report Currituck County WR No. 23-0292 February 2024 Appendix 4: Opinions of Probable Costs  Proposed Improvement Area 1 Cost Opinion  Proposed Improvement Area 2 Cost Opinion Project Name: Currituck County RCCP Phase 3 Project #: 23-0292 City/State: Currituck, North Carolina Date: 2/5/2024 Baxter Lane Concept Area - Drainage Improvement Quantity* Unit Unit Price Total 2760 LF 50$ 138,000$ 60 LF 90$ 5,400$ 2 EA 3,000$ 6,000$ 2000 CY 12$ 24,000$ 23 SY 40$ 920$ % of Material Cost 5% $ 9,000 3% $ 6,000 2% $ 4,000 2% $ 4,000 SUBTOTAL $ 197,320 % of Material Subtotal 15% $ 30,000 35% $ 70,000 CONSTRUCTION SUBTOTAL $ 297,320 % of Construction Subtotal 5% $ 15,000 10% $ 30,000 25% $ 75,000 1% $ 2,000 ENGINEERING & ADMINISTRATION SUBTOTAL $ 122,000 PROJECT TOTAL $ 419,320 Assumptions Proposed Improvements Structure 6' Bottom Width Drainage Ditch Traffic Control 24" RCP Headwall/Endwall Remove Excess Soil Offsite Pavement Replacement Mobilization Erosion Control Dewatering Cost Escalation Factor Contingency Design Construction Administration Closeout This estimate of probable cost is approximate. Actual construction bids may vary significantly from this statement of probable construction costs due to the timing of construction, changed conditions, labor rate changes, or other factors beyond the control of the estimators. This estimate does not consider costs associated with permitting, land or easement acquisition, utility relocation, or additional improvements. Site Characterization (Survey & Geotech) Project Name: Currituck County RCCP Phase 3 Project #: 23-0292 City/State: Currituck, North Carolina Date: 2/5/2024 Rocky Top Concept Area - Old Tulls Bay Rd Drainage Improvement Quantity*Unit Unit Price Total 1500 LF 90$ 135,000$ 1940 CY 12$ 23,280$ 152 LF 20$ 3,040$ % of Material Cost 5% $ 9,000 3% $ 5,000 1% $ 2,000 2% $ 4,000 SUBTOTAL $ 181,320 % of Material Subtotal 15% $ 28,000 35% $ 64,000 CONSTRUCTION SUBTOTAL $ 273,320 % of Construction Subtotal 5% $ 14,000 10% $ 28,000 25% $ 69,000 1% $ 2,000 ENGINEERING & ADMINISTRATION SUBTOTAL $ 113,000 PROJECT TOTAL $ 386,320 Assumptions Proposed Improvements Structure 14' Bottom Width Drainage Ditch Traffic Control Remove Excess Soil Offsite Diversion Berm Mobilization Erosion Control This estimate of probable cost is approximate. Actual construction bids may vary significantly from this statement of probable construction costs due to the timing of construction, changed conditions, labor rate changes, or other factors beyond the control of the estimators. This estimate does not consider costs associated with permitting, land or easement acquisition, utility relocation, or additional improvements. Design Construction Administration Closeout Site Characterization (Survey & Geotech) Dewatering Cost Escalation Factor Contingency RCCP Phase 3 Design Report Currituck County WR No. 23-0292 February 2024 Appendix 5: Concept Project Fact Sheets  Area 1 – Baxter Lane Fact Sheet  Area 2 – Old Tulls Creek Road Fact Sheet