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
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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.
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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
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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
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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
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Row
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Rocky Top Rd
Franklin
Ln
Dolphin
St
W renDr
Meadow
B
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Chip Dr
Geo
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Dr
Th
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D urbins
Ln
Perc
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Marlin
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Trout
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Shar
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St
Bass
St
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Porp
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S
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Our
S
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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
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i
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D
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GuineaMillRd
BeechwoodShoresDr
W il d w o o d
F a r m s A v e
Matildas
Trace
GuineaRd
Spr
u
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Ln
Old TullsCreek Rd
P
o
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n
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R
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St
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S
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Old J
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R
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River Rd
Carat
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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
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4.9
8.5 4.8
8.6
4.8
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8.5
4.5
4.2
4.6
4.7
4.
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4.4
8.6
4.3
8.8
8.6
8.7
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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
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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