20201340 Ver 2_1100 Old English 1% Annual Floodplain Analysis - 10-13-2023 - Stamped_20231208

HYDROLOGIC & HYDRAULIC ANALYSIS
1100 Old English Court
City of Raleigh, Wake County, North Carolina
October 2023
Calculations By: Alston Willard, EIT and Jacob Wines
Checked By: Chris Rogers, PE
Timmons Group
5410 Trinity Road, Suite 102
Raleigh, North Carolina 27607
NC Firm License: C-1652
TIMMONS GROUP
YOUR VISION ACHIEVED THROUGH OURS.

TABLE OF CONTENTS
TABLE OF CONTENTS------------------------------------------------------------------------- i
LIST OF
TABLES--------------------------------------------------------------------------------- i
LIST OF
APPENDICES-------------------------------------------------------------------------- i
1.0
PROJECT SUMMARY----------------------------------------------------------------- 1
2.0
HYDROLOGIC ANALYSIS------------------------------------------------------------- 1
3.0
HYDRAULIC ANALYSIS--------------------------------------------------------------- 2
3.1 EXISTING CONDTIONS---------------------------------------------------- 2
3.2 PROPOSED CONDTIONS-------------------------------------------------- 2
4.0
RESULTS-------------------------------------------------------------------------------- 4
5.0
COMPUTER MODELS---------------------------------------------------------------- 4
LIST OF TABLES
Table A
—Composite Curve Number---------------------------------------------------------------- 1
Table B—Times
of Concentration and Lag Times ----------------------------------------------- 2
Table C
— 1% Annual Peak Discharges-------------------------------------------------------------- 2
Table D
— Mill Creek Lot 14 Model Flow Change Locations------------------------------------ 3
Table E
— Mill Creek Lot 14 Model Water Surface Elevations --------------------------------- 3
LIST OF APPENDICES
Appendix A — Hydrologic Calculations
Watershed Map
Site Soils Map
NOAA Atlas 14 PFDS Rainfall Depth Table
Hydrology — NRCS Curve Number Worksheets
Time of Concentration and Lag Time Worksheets
HydroCAD Output Tables
Appendix B — Hydraulic Calculations
Floodplain Boundary Workmap
HEC-RAS Cross Sections
HEC-RAS Output Tables
Timmons Group Page i 1100 Old Englsih
Hydrologic & Hydraulic Analysis

Hydrologic & Hydraulic Analysis
1100 Old English
1.0 PROJECT SUMMARY
The project is located in Old English Downs Subdivision at 1100 Old English Court, Raleigh,
North Carolina. An unnamed tributary to West Fork Mine Creek (UT WF Mine Creek) is located
in the back yard of the property. The outside of a meander bend in the stream is currently
actively eroding and migrating towards the existing house structure. Approximately 170 linear
feet of stream have been identified for repair and improvement through the City of Raleigh
Drainage Assistance Program.
During submission of the stabilization plan, the City of Raleigh revised the City's Unified
Development Ordinance (UDO) in July 2022 that required a flood study to be completed for
projects within hydric soils. The project is within flood hazard soils Cm and Me and requires the
establishment of a 1% annual chance floodplain to ensure that no permanent structures will be
impacted in the proposed conditions.
The purpose of the hydrologic analysis was to develop a 1% annual peak discharge through the
site along the unnamed tributary and produce a hydraulic model to see the impact of the 1%
annual flood elevations. The existing stream and morphological survey was conducted by
Timmons Group in February 2020 and surrounding topography was surveyed by RWK, PA
Engineering Surveying in the same month.
2.0 HYDROLOGIC ANALYSIS
The HydroCAD Software Solutions LLC (HydroCAD) software version 10.10-7a was used for the
hydrologic analysis. To model the catchment data, the NRCS Curve Number method was used.
The hydrologic calculations and drainage area map are included in Appendix A. Input data for the
HydroCAD model is as follows:
• The drainage areas were delineated based on LiDAR contours obtained from NCFloodmaps.
• The drainage area was modeled using the NRCS Curve Number method using the Unit
Hydrograph. Composite Curve Numbers were calculated for existing conditions of the
watershed. Given the size of the watershed and the fact that the proposed changes represent
a small portion of the watershed, curve numbers were calculated to the nearest whole
number. The curve numbers were adjusted using an initial abstraction ratio of 0.05 as
discussed in a study by Richard Hawkins, et al. The watershed map is included in Appendix A.
The drainage areas and adjusted composite curve numbers are shown in Table A.
Table A — Composite Curve Number
Timmons Group Page 1 1100 Old English
Hydrologic & Hydraulic Analysis

• The time of concentration (Tc) was calculated using the basin average slope method. The
times of concentration are shown in Table B.
Table B — Times of Concentration and Lag Times
• The drainage area is modeled as a sub catchment and discharges to the point of interest at
the downstream discharge point located at the downstream point of stabilization area at
1100 Old English Court.
• The drainage area was imputed with the composite curve number and drainage area
referenced in Table A and time of concentration referenced in Table B.
• The meteorological data used was obtained from NOAA Atlas 14 PFDS Rainfall Depth Table.
The model used the frequency storm over a 24-hour period.
• The model was run using a Type II, 24-hr storm event and the results of the HydroCAD model
for the 1% annual peak storm event are shown in Table C.
DRAINAG 1% ANNUAL PEAK
AREA DISCHARGE (CFS)
NUMBER
�� :� •
3.0 HYDRAULIC ANALYSIS
The stream was modeled using the USACE River Analysis System (HEC-RAS) version 6.4.1. The
stream runs from North to South. The stream was modeled in a single HEC-RAS simulation
named Floodplain Analysis for existing and proposed condition plans. The model for the stream
was created with a project file named Flood plainAnalysis.prj. The proposed conditions shifted
the stream centerline which adjusted stream stations for all cross sections upstream of cross
section 104. The cross sections were taken from the same geographic locations as the existing
conditions but the shift in stream centerline changed downstream lengths. This is seen in the
tables below with a "/" between the existing and proposed cross section stations. The order is
as follows "existing station/proposed station". Cross sections 104 and 6 were the same because
the proposed alignment joined back into the existing conditions alignment upstream of cross
section 104.
3.1 EXISTING CONDITIONS
The existing conditions analysis is based off surveyed contours and GIS LiDAR data. The plan file
was named Existing Conditions (.p01), the geometry file was named Existing Conditions (.g01),
and a flow file with peak flows generated in the hydrologic study discussed in section 2.0.
Timmons Group Page 2 1100 Old English
Hydrologic & Hydraulic Analysis

• The cross sections were modeled from the survey and LiDAR data. Manning's n-values were
assigned for the overbank and channel. The overbank n-value was set as 0.12. The channel
n-value was set at 0.045. The model was developed with single reach.
• The existing building at 1100 Old English and deck was added as obstructions in two cross
sections. An obstruction was added on cross section station 278 and 244 to represent the
permanent structures. The obstruction was added between station 518.58 and 530.32 with
an elevation of 320 in cross section 278. The obstruction was added between station 513.4
and 522.62 with an elevation of 315 in cross section 244.
3.2 PROPOSED CONDITIONS
The proposed conditions analysis is based off surveyed contours, GIS LiDAR data and proposed
contours. The plan file was named Proposed Conditions (.p02), the geometry file was named
Proposed Conditions (.g02), and a flow file with peak flows generated in the hydrologic study
discussed in section 2.0.
• The cross sections were modeled from the survey and LiDAR data. Manning's n-values were
assigned for the overbank and channel. The overbank n-value was set as 0.12. The channel
n-value was set at 0.045. The model was developed with single reach.
• The existing building at 1100 Old English and deck was added as obstructions in the same two
cross sections as the existing conditions.
• The steady flow file was created and named 1% Peak Flow. The downstream boundary
conditions were set as normal flow with a stream slope of 0.01 ft/ft. The flow changes are
located at the cross-section stations shown in Table D.
Table D — Mill Creek Model Flow Change Locations Existing Condition
Cross Section 1% Peak Discharge (Cfsm
330/308 848
The model was run, and the water surface elevations (WSEL) created for Existing and Post Project
condition 1% annual storm event along the studied reach. The water surface elevations
comparison is shown in Table E.
Table E — Mill Creek Model Water Surface Elevations
Existing
I Post Project
WSEL Difference
Cross Section
Base Flood Elevation
1% Annual
Base Flood Elevation
1% Annual
(Post Project-
Exiting) (ft)
t .1111.
(ft) JL
(ft) ,L
Timmons Group Page 3 1100 Old English
Hydrologic & Hydraulic Analysis

4.0 RESULTS
The hydraulic modeling results shows there is no increase in 1% annual storm event and no
adjacent structures are disturbed due to the proposed design of the stream. The 1% annual peak
discharge did not increase because full build out of the watershed was not considered for this
study. The goal of this study was to ensure that no adjacent structures would be impacted due
to the proposed improvements. In order to isolate the proposed design as the only variable
changing across both studies the 1% annual peak discharge was kept the same for both runs. The
hydraulic analysis shows that there is a decrease in water surface elevation across the project
site. The 1% annual inundation has been delineated and is shown on the flood study work map
included in Appendix B.
5.0 COMPUTER MODELS
The following computer models have been included with this report:
H EC-RAS
Floodplain Analysis
Project: Floodplain Analysis Flood plainAnalysis.prj
Plan: Existing Conditions Flood plainAnalysis.p01
Geometry:
Steady Flow
Project:
Plan:
Geometry:
Steady Flow
HYDROCAD
Mill Creek Lot 14
Existing Conditions
1% Peak Flow
Floodplain Analysis
Proposed Conditions
Proposed Conditions
1% Peak Flow — post
Project File Name: 1100 Old English Court.hcp
Flood plainAnalysis.g01
Flood plainAnalysis.f01
Flood plainAnalysis.prj
Flood plainAnalysis.p02
Flood plainAnalysis.g02
Flood plainAnalysisJ02
Timmons Group Page 4 1100 Old English
Hydrologic & Hydraulic Analysis

APPENDIX A
HYDROLOGY
Watershed Map
Site Soils Map
NOAA Atlas 14 PFDS Rainfall Depth Table
Hydrology - NRCS Curve Number Sheets
Basin Average Slope Sheets
HydroCAD Output Tables
StreamStats Report

USDA United States
Department of
Agriculture
N RCS
Natural
Resources
Conservation
Service
A product of the National
Cooperative Soil Survey,
a joint effort of the United
States Department of
Agriculture and other
Federal agencies, State
agencies including the
Agricultural Experiment
Stations, and local
participants
Custom Soil Resource
Report for
Alamance County, North
Carolina, and Orange
County, North Carolina
August 16, 2023

Preface
Soil surveys contain information that affects land use planning in survey areas.
They highlight soil limitations that affect various land uses and provide information
about the properties of the soils in the survey areas. Soil surveys are designed for
many different users, including farmers, ranchers, foresters, agronomists, urban
planners, community officials, engineers, developers, builders, and home buyers.
Also, conservationists, teachers, students, and specialists in recreation, waste
disposal, and pollution control can use the surveys to help them understand,
protect, or enhance the environment.
Various land use regulations of Federal, State, and local governments may impose
special restrictions on land use or land treatment. Soil surveys identify soil
properties that are used in making various land use or land treatment decisions.
The information is intended to help the land users identify and reduce the effects of
soil limitations on various land uses. The landowner or user is responsible for
identifying and complying with existing laws and regulations.
Although soil survey information can be used for general farm, local, and wider area
planning, onsite investigation is needed to supplement this information in some
cases. Examples include soil quality assessments (http://www.nres.usda.gov/wps/
portal/nres/main/soils/health/) and certain conservation and engineering
applications. For more detailed information, contact your local USDA Service Center
(https:Hoffices.sc.egov.usda.gov/locator/app?agency=nres) or your NRCS State Soil
Scientist (http://www.nres.usda.gov/wps/portal/nres/detail/soils/contactus/?
cid=nres142p2_053951).
Great differences in soil properties can occur within short distances. Some soils are
seasonally wet or subject to flooding. Some are too unstable to be used as a
foundation for buildings or roads. Clayey or wet soils are poorly suited to use as
septic tank absorption fields. A high water table makes a soil poorly suited to
basements or underground installations.
The National Cooperative Soil Survey is a joint effort of the United States
Department of Agriculture and other Federal agencies, State agencies including the
Agricultural Experiment Stations, and local agencies. The Natural Resources
Conservation Service (NRCS) has leadership for the Federal part of the National
Cooperative Soil Survey.
Information about soils is updated periodically. Updated information is available
through the NRCS Web Soil Survey, the site for official soil survey information.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its
programs and activities on the basis of race, color, national origin, age, disability,
and where applicable, sex, marital status, familial status, parental status, religion,
sexual orientation, genetic information, political beliefs, reprisal, or because all or a
part of an individual's income is derived from any public assistance program. (Not
all prohibited bases apply to all programs.) Persons with disabilities who require

alternative means for communication of program information (Braille, large print,
audiotape, etc.) should contact USDA's TARGET Center at [phone] (voice
and TDD). To file a complaint of discrimination, write to USDA, Director, Office of
Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or
call [phone] (voice) or [phone] (TDD). USDA is an equal opportunity
provider and employer.

Contents
Preface......................................................................................................... .
How Soil Surveys Are Made........................................................................
SoilMap........................................................................................................
SoilMap......................................................................................................
Legend........................................................................................................
MapUnit Legend........................................................................................
Map Unit Descriptions................................................................................
Alamance County, North Carolina...........................................................
CnB2—Cullen clay loam, 2 to 6 percent slopes, moderately eroded..
CnC2—Cullen clay loam, 6 to 10 percent slopes, moderately eroded
EnB—Enon sandy loam, 2 to 6 percent slopes ...................................
EnC—Enon sandy loam, 6 to 10 percent slopes .................................
MaB—Mandale-Secrest complex, 2 to 6 percent slopes ....................
W—Water........................................................................................... .
Orange County, North Carolina...............................................................
Ch—Chewacla loam, 0 to 2 percent slopes, frequently flooded..........
EnB—Enon loam, 2 to 6 percent slopes .............................................
GeB—Georgeville silt loam, 2 to 6 percent slopes ..............................
GeC—Georgeville silt loam, 6 to 10 percent slopes ............................
HrB—Herndon silt loam, 2 to 6 percent slopes ...................................
HrC—Herndon silt loam, 6 to 10 percent slopes .................................
Lg—Lignum silt loam, 0 to 3 percent slopes .......................................
Or —Orange silt loam, 0 to 3 percent slopes .......................................
References....................................................................................................
.2
..5
.8
..9
10
12
12
15
15
16
17
18
19
20
22
22
23
24
25
26
27
28
29
31

How Soil Surveys Are Made
Soil surveys are made to provide information about the soils and miscellaneous
areas in a specific area. They include a description of the soils and miscellaneous
areas and their location on the landscape and tables that show soil properties and
limitations affecting various uses. Soil scientists observed the steepness, length,
and shape of the slopes; the general pattern of drainage; the kinds of crops and
native plants; and the kinds of bedrock. They observed and described many soil
profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The
profile extends from the surface down into the unconsolidated material in which the
soil formed or from the surface down to bedrock. The unconsolidated material is
devoid of roots and other living organisms and has not been changed by other
biological activity.
Currently, soils are mapped according to the boundaries of major land resource
areas (MLRAs). MLRAs are geographically associated land resource units that
share common characteristics related to physiography, geology, climate, water
resources, soils, biological resources, and land uses (USDA, 2006). Soil survey
areas typically consist of parts of one or more MLRA.
The soils and miscellaneous areas in a survey area occur in an orderly pattern that
is related to the geology, landforms, relief, climate, and natural vegetation of the
area. Each kind of soil and miscellaneous area is associated with a particular kind
of landform or with a segment of the landform. By observing the soils and
miscellaneous areas in the survey area and relating their position to specific
segments of the landform, a soil scientist develops a concept, or model, of how they
were formed. Thus, during mapping, this model enables the soil scientist to predict
with a considerable degree of accuracy the kind of soil or miscellaneous area at a
specific location on the landscape.
Commonly, individual soils on the landscape merge into one another as their
characteristics gradually change. To construct an accurate soil map, however, soil
scientists must determine the boundaries between the soils. They can observe only
a limited number of soil profiles. Nevertheless, these observations, supplemented
by an understanding of the soil -vegetation -landscape relationship, are sufficient to
verify predictions of the kinds of soil in an area and to determine the boundaries.
Soil scientists recorded the characteristics of the soil profiles that they studied. They
noted soil color, texture, size and shape of soil aggregates, kind and amount of rock
fragments, distribution of plant roots, reaction, and other features that enable them
to identify soils. After describing the soils in the survey area and determining their
properties, the soil scientists assigned the soils to taxonomic classes (units).
Taxonomic classes are concepts. Each taxonomic class has a set of soil
characteristics with precisely defined limits. The classes are used as a basis for
comparison to classify soils systematically. Soil taxonomy, the system of taxonomic
classification used in the United States, is based mainly on the kind and character
of soil properties and the arrangement of horizons within the profile. After the soil

Custom Soil Resource Report
scientists classified and named the soils in the survey area, they compared the
individual soils with similar soils in the same taxonomic class in other areas so that
they could confirm data and assemble additional data based on experience and
research.
The objective of soil mapping is not to delineate pure map unit components; the
objective is to separate the landscape into landforms or landform segments that
have similar use and management requirements. Each map unit is defined by a
unique combination of soil components and/or miscellaneous areas in predictable
proportions. Some components may be highly contrasting to the other components
of the map unit. The presence of minor components in a map unit in no way
diminishes the usefulness or accuracy of the data. The delineation of such
landforms and landform segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, onsite
investigation is needed to define and locate the soils and miscellaneous areas.
Soil scientists make many field observations in the process of producing a soil map.
The frequency of observation is dependent upon several factors, including scale of
mapping, intensity of mapping, design of map units, complexity of the landscape,
and experience of the soil scientist. Observations are made to test and refine the
soil -landscape model and predictions and to verify the classification of the soils at
specific locations. Once the soil -landscape model is refined, a significantly smaller
number of measurements of individual soil properties are made and recorded.
These measurements may include field measurements, such as those for color,
depth to bedrock, and texture, and laboratory measurements, such as those for
content of sand, silt, clay, salt, and other components. Properties of each soil
typically vary from one point to another across the landscape.
Observations for map unit components are aggregated to develop ranges of
characteristics for the components. The aggregated values are presented. Direct
measurements do not exist for every property presented for every map unit
component. Values for some properties are estimated from combinations of other
properties.
While a soil survey is in progress, samples of some of the soils in the area generally
are collected for laboratory analyses and for engineering tests. Soil scientists
interpret the data from these analyses and tests as well as the field -observed
characteristics and the soil properties to determine the expected behavior of the
soils under different uses. Interpretations for all of the soils are field tested through
observation of the soils in different uses and under different levels of management.
Some interpretations are modified to fit local conditions, and some new
interpretations are developed to meet local needs. Data are assembled from other
sources, such as research information, production records, and field experience of
specialists. For example, data on crop yields under defined levels of management
are assembled from farm records and from field or plot experiments on the same
kinds of soil.
Predictions about soil behavior are based not only on soil properties but also on
such variables as climate and biological activity. Soil conditions are predictable over
long periods of time, but they are not predictable from year to year. For example,
soil scientists can predict with a fairly high degree of accuracy that a given soil will
have a high water table within certain depths in most years, but they cannot predict
that a high water table will always be at a specific level in the soil on a specific date.
After soil scientists located and identified the significant natural bodies of soil in the
survey area, they drew the boundaries of these bodies on aerial photographs and

Custom Soil Resource Report
identified each as a specific map unit. Aerial photographs show trees, buildings,
fields, roads, and rivers, all of which help in locating boundaries accurately.

Soil Map
The soil map section includes the soil map for the defined area of interest, a list of
soil map units on the map and extent of each map unit, and cartographic symbols
displayed on the map. Also presented are various metadata about data used to
produce the map, and a description of each soil map unit.

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Custom Soil Resource Report
Map Unit Legend
Map Unit Symbol
Map Unit Name
Acres in AOI
Percent of AOI
CnB2
Cullen clay loam, 2 to 6 percent
slopes, moderately eroded
14.7
5.4%
CnC2
Cullen clay loam, 6 to 10
percent slopes, moderately
eroded
11.1
4.1 %
EnB
Enon sandy loam, 2 to 6
percent slopes
3.9
1.4%
EnC
Enon sandy loam, 6 to 10
percent slopes
9.8
3.6%
MaB
Mandale-Secrest complex, 2 to
6 percent slopes
2.9
1.1 %
W
Water
0.4
0.1 %
Subtotals for Soil Survey Area
42.8
16.8%
Totals for Area of Interest
271.6
100.0%
Map Unit Symbol
Map Unit Name
Acres in AOI
Percent of AOI
Ch
Chewacla loam, 0 to 2 percent
slopes, frequently flooded
3.0
1.1 %
EnB
Enon loam, 2 to 6 percent
slopes
9.2
3.4%
GeB
Georgeville silt loam, 2 to 6
percent slopes
99.0
36.5%
GeC
Georgeville silt loam, 6 to 10
percent slopes
3.6
1.3%
HrB
Herndon silt loam, 2 to 6
percent slopes
44.4
16.4%
HrC
Herndon silt loam, 6 to 10
percent slopes
12.9
4.8%
Lg
Lignum silt loam, 0 to 3 percent
slopes
2.1
0.8%
Or
Orange silt loam, 0 to 3 percent
slopes
54.5
20.1 %
Subtotals for Soil Survey Area
228.7
84.2%
Totals for Area of Interest
271.6
100.0%
Map Unit Descriptions
The map units delineated on the detailed soil maps in a soil survey represent the
soils or miscellaneous areas in the survey area. The map unit descriptions, along
with the maps, can be used to determine the composition and properties of a unit.
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Custom Soil Resource Report
A map unit delineation on a soil map represents an area dominated by one or more
major kinds of soil or miscellaneous areas. A map unit is identified and named
according to the taxonomic classification of the dominant soils. Within a taxonomic
class there are precisely defined limits for the properties of the soils. On the
landscape, however, the soils are natural phenomena, and they have the
characteristic variability of all natural phenomena. Thus, the range of some
observed properties may extend beyond the limits defined for a taxonomic class.
Areas of soils of a single taxonomic class rarely, if ever, can be mapped without
including areas of other taxonomic classes. Consequently, every map unit is made
up of the soils or miscellaneous areas for which it is named and some minor
components that belong to taxonomic classes other than those of the major soils.
Most minor soils have properties similar to those of the dominant soil or soils in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
management. These are called contrasting, or dissimilar, components. They
generally are in small areas and could not be mapped separately because of the
scale used. Some small areas of strongly contrasting soils or miscellaneous areas
are identified by a special symbol on the maps. If included in the database for a
given area, the contrasting minor components are identified in the map unit
descriptions along with some characteristics of each. A few areas of minor
components may not have been observed, and consequently they are not
mentioned in the descriptions, especially where the pattern was so complex that it
was impractical to make enough observations to identify all the soils and
miscellaneous areas on the landscape.
The presence of minor components in a map unit in no way diminishes the
usefulness or accuracy of the data. The objective of mapping is not to delineate
pure taxonomic classes but rather to separate the landscape into Iandforms or
Iandform segments that have similar use and management requirements. The
delineation of such segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, however,
onsite investigation is needed to define and locate the soils and miscellaneous
areas.
An identifying symbol precedes the map unit name in the map unit descriptions.
Each description includes general facts about the unit and gives important soil
properties and qualities.
Soils that have profiles that are almost alike make up a soil series. Except for
differences in texture of the surface layer, all the soils of a series have major
horizons that are similar in composition, thickness, and arrangement.
Soils of one series can differ in texture of the surface layer, slope, stoniness,
salinity, degree of erosion, and other characteristics that affect their use. On the
basis of such differences, a soil series is divided into soil phases. Most of the areas
shown on the detailed soil maps are phases of soil series. The name of a soil phase
commonly indicates a feature that affects use or management. For example, Alpha
silt loam, 0 to 2 percent slopes, is a phase of the Alpha series.
Some map units are made up of two or more major soils or miscellaneous areas.
These map units are complexes, associations, or undifferentiated groups.
A complex consists of two or more soils or miscellaneous areas in such an intricate
pattern or in such small areas that they cannot be shown separately on the maps.
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Custom Soil Resource Report
The pattern and proportion of the soils or miscellaneous areas are somewhat similar
in all areas. Alpha -Beta complex, 0 to 6 percent slopes, is an example.
An association is made up of two or more geographically associated soils or
miscellaneous areas that are shown as one unit on the maps. Because of present
or anticipated uses of the map units in the survey area, it was not considered
practical or necessary to map the soils or miscellaneous areas separately. The
pattern and relative proportion of the soils or miscellaneous areas are somewhat
similar. Alpha -Beta association, 0 to 2 percent slopes, is an example.
An undifferentiated group is made up of two or more soils or miscellaneous areas
that could be mapped individually but are mapped as one unit because similar
interpretations can be made for use and management. The pattern and proportion
of the soils or miscellaneous areas in a mapped area are not uniform. An area can
be made up of only one of the major soils or miscellaneous areas, or it can be made
up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include miscellaneous areas. Such areas have little or no soil
material and support little or no vegetation. Rock outcrop is an example.
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Custom Soil Resource Report
Alamance County, North Carolina
CnB2—Cullen clay loam, 2 to 6 percent slopes, moderately eroded
Map Unit Setting
National map unit symbol. 2xn4j
Elevation: 330 to 980 feet
Mean annual precipitation: 39 to 47 inches
Mean annual air temperature: 55 to 63 degrees F
Frost -free period: 200 to 250 days
Farmland classification: All areas are prime farmland
Map Unit Composition
Cullen, moderately eroded, and similar soils: 95 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Cullen, Moderately Eroded
Setting
Landform: I me rfluves
Landform position (two-dimensional): Summit
Landform position (three-dimensional): Interfluve
Down -slope shape: Convex
Across -slope shape: Convex
Parent material: Mixed residuum weathered from igneous and metamorphic rock
Typical profile
Ap - 0 to 10 inches: clay loam
Bt - 10 to 50 inches: clay
BC - 50 to 69 inches: silty clay
CB - 69 to 80 inches: silty clay loam
Properties and qualities
Slope: 2 to 6 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Well drained
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high
(0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: Moderate (about 7.2 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: B
Ecological site: F136XY820GA - Acidic upland forest, moist
Hydric soil rating: No
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Custom Soil Resource Report
CnC2—Cullen clay loam, 6 to 10 percent slopes, moderately eroded
Map Unit Setting
National map unit symbol. 2xn4k
Elevation: 330 to 980 feet
Mean annual precipitation: 39 to 47 inches
Mean annual air temperature: 55 to 63 degrees F
Frost -free period: 200 to 250 days
Farmland classification: Farmland of statewide importance
Map Unit Composition
Cullen, moderately eroded, and similar soils: 95 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Cullen, Moderately Eroded
Setting
Landform: I me rfluves
Landform position (two-dimensional): Shoulder, backslope
Landform position (three-dimensional): Side slope
Down -slope shape: Concave
Across -slope shape: Linear
Parent material: Mixed residuum weathered from igneous and metamorphic rock
Typical profile
Ap - 0 to 10 inches: clay loam
Bt - 10 to 50 inches: clay
BC - 50 to 69 inches: silty clay
CB - 69 to 80 inches: silty clay loam
Properties and qualities
Slope: 6 to 10 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Well drained
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high
(0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: Moderate (about 7.2 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: B
Ecological site: F136XY820GA - Acidic upland forest, moist
Hydric soil rating: No
it.

Custom Soil Resource Report
EnB—Enon sandy loam, 2 to 6 percent slopes
Map Unit Setting
National map unit symbol: 2xn4s
Elevation: 330 to 980 feet
Mean annual precipitation: 39 to 47 inches
Mean annual air temperature: 55 to 63 degrees F
Frost -free period: 200 to 250 days
Farmland classification: All areas are prime farmland
Map Unit Composition
Enon and similar soils: 90 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Enon
Setting
Landform: Imerfluves
Landform position (two-dimensional): Summit
Landform position (three-dimensional): Interfluve
Down -slope shape: Convex
Across -slope shape: Convex
Parent material: Residuum weathered from diorite and/or gabbro and/or diabase
and/or hornblende gneiss
Typical profile
A - 0 to 9 inches: sandy loam
Bt - 9 to 34 inches: clay
BC - 34 to 41 inches: clay loam
C - 41 to 80 inches: sandy loam
Properties and qualities
Slope: 2 to 6 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Well drained
Capacity of the most limiting layer to transmit water (Ksat): Moderately low to
moderately high (0.06 to 0.20 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: High (about 9.0 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 2e
Hydrologic Soil Group: C
Ecological site: F136XY72ONC -Basic upland forest, moist
Hydric soil rating: No
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Custom Soil Resource Report
EnC—Enon sandy loam, 6 to 10 percent slopes
Map Unit Setting
National map unit symbol: 2xn4t
Elevation: 330 to 980 feet
Mean annual precipitation: 39 to 47 inches
Mean annual air temperature: 55 to 63 degrees F
Frost -free period: 200 to 250 days
Farmland classification: Farmland of statewide importance
Map Unit Composition
Enon and similar soils: 90 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Enon
Setting
Landform: Imerfluves
Landform position (two-dimensional): Backslope, shoulder
Landform position (three-dimensional): Side slope
Down -slope shape: Concave
Across -slope shape: Linear
Parent material: Residuum weathered from diorite and/or gabbro and/or diabase
and/or hornblende gneiss
Typical profile
A - 0 to 9 inches: sandy loam
Bt - 9 to 34 inches: clay
BC - 34 to 41 inches: clay loam
C - 41 to 80 inches: sandy loam
Properties and qualities
Slope: 6 to 10 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Well drained
Capacity of the most limiting layer to transmit water (Ksat): Moderately low to
moderately high (0.06 to 0.20 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: High (about 9.0 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: C
Ecological site: F136XY72ONC -Basic upland forest, moist
Hydric soil rating: No
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Custom Soil Resource Report
MaB—Mandale-Secrest complex, 2 to 6 percent slopes
Map Unit Setting
National map unit symbol. 2xn5y
Elevation: 330 to 980 feet
Mean annual precipitation: 39 to 47 inches
Mean annual air temperature: 55 to 63 degrees F
Frost -free period: 200 to 250 days
Farmland classification: Farmland of statewide importance
Map Unit Composition
Mandale and similar soils: 50 percent
Secrest and similar soils: 42 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Mandale
Setting
Landform: Sloughs on interfluves, depressions on interfluves, drainageways on
interfluves, flats on interfluves
Landform position (two-dimensional): Toeslope, summit
Landform position (three-dimensional): Interfluve, talf, dip, rise
Down -slope shape: Linear, convex
Across -slope shape: Linear, concave, convex
Parent material: Residuum weathered from argillite
Typical profile
A - 0 to 7 inches: silt loam
Bt - 7 to 48 inches: silty clay loam
BCtg - 48 to 55 inches: clay loam
C - 55 to 64 inches: fine sandy loam
Cr - 64 to 78 inches: bedrock
R - 78 to 80 inches: bedrock
Properties and qualities
Slope: 2 to 6 percent
Depth to restrictive feature: 60 to 80 inches to paralithic bedrock; 60 to 80 inches
to lithic bedrock
Drainage class: Somewhat poorly drained
Capacity of the most limiting layer to transmit water (Ksat): Very low to moderately
low (0.00 to 0.14 in/hr)
Depth to water table: About 12 to 24 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: High (about 10.2 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 3w
Hydrologic Soil Group: C/D
Ecological site: F136XY810SC - Acidic upland forest, seasonally wet
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Custom Soil Resource Report
Hydric soil rating: No
Description of Secrest
Setting
Landform: Sloughs on interfluves, depressions on interfluves, drainageways on
interfluves, flats on interfluves
Landform position (two-dimensional): Toeslope, summit
Landform position (three-dimensional): Interfluve, talf, dip, rise
Down -slope shape: Linear, convex
Across -slope shape: Linear, convex, concave
Parent material: Residuum weathered from argillite
Typical profile
A - 0 to 6 inches: silt loam
Bt - 6 to 41 inches: silty clay loam
BC - 41 to 49 inches: loam
Cr - 49 to 61 inches: bedrock
R - 61 to 80 inches: bedrock
Properties and qualities
Slope: 2 to 6 percent
Depth to restrictive feature: 40 to 60 inches to paralithic bedrock; 60 to 80 inches
to Iithic bedrock
Drainage class: Moderately well drained
Capacity of the most limiting layer to transmit water (Ksat): Very low to moderately
high (0.00 to 0.60 in/hr)
Depth to water table: About 18 to 30 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: Moderate (about 8.8 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 2e
Hydrologic Soil Group: C
Ecological site: F136XY810SC - Acidic upland forest, seasonally wet
Hydric soil rating: No
ViTAMY 'i
Map Unit Composition
Water.- 100 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Water
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 8w
Hydric soil rating: No
20

Custom Soil Resource Report
21

Custom Soil Resource Report
Orange County, North Carolina
Ch—Chewacla loam, 0 to 2 percent slopes, frequently flooded
Map Unit Setting
National map unit symbol: 2vy6r
Elevation: 330 to 660 feet
Mean annual precipitation: 39 to 47 inches
Mean annual air temperature: 55 to 63 degrees F
Frost -free period: 200 to 250 days
Farmland classification: Prime farmland if drained and either protected from flooding
or not frequently flooded during the growing season
Map Unit Composition
Chewacla, frequently flooded, and similar soils: 90 percent
Minor components: 5 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Chewacla, Frequently Flooded
Setting
Landform: Flood plains
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Tread, talf
Down -slope shape: Linear
Across -slope shape: Linear
Parent material: Loamy alluvium derived from igneous and metamorphic rock
Typical profile
Ap - 0 to 6 inches: loam
Bw - 6 to 52 inches: sandy clay loam
Cg - 52 to 80 inches: stratified sandy loam
Properties and qualities
Slope: 0 to 2 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Somewhat poorly drained
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high
(0.20 to 2.00 in/hr)
Depth to water table: About 6 to 24 inches
Frequency of flooding: NoneFrequent
Frequency of ponding: None
Available water supply, 0 to 60 inches: Moderate (about 7.6 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 4w
Hydrologic Soil Group: B/D
Ecological site: F136XY610GA - Flood plain forest, wet
Hydric soil rating: No
Minor Components
Wehadkee, frequently flooded
Percent of map unit. 5 percent
Landform: Flood plains
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Custom Soil Resource Report
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Tread, talf
Down -slope shape: Linear
Across -slope shape: Linear
Hydric soil rating: Yes
EnB—Enon loam, 2 to 6 percent slopes
Map Unit Setting
National map unit symbol: 3tgI
Elevation: 200 to 1,400 feet
Mean annual precipitation: 37 to 60 inches
Mean annual air temperature: 59 to 66 degrees F
Frost -free period: 200 to 240 days
Farmland classification: All areas are prime farmland
Map Unit Composition
Enon and similar soils: 90 percent
Minor components: 1 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Enon
Setting
Landform: Imerfluves
Landform position (two-dimensional): Summit
Landform position (three-dimensional): Interfluve
Down -slope shape: Convex
Across -slope shape: Convex
Parent material: Saprolite derived from diorite and/or gabbro and/or diabase
and/or gneiss
Typical profile
A - 0 to 3 inches: fine sandy loam
E - 3 to 8 inches: fine sandy loam
BE - 8 to 11 inches: sandy clay loam
Bt - 11 to 33 inches: clay
C - 33 to 80 inches: loam
Properties and qualities
Slope: 2 to 6 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Well drained
Runoff class: Low
Capacity of the most limiting layer to transmit water (Ksat): Moderately low to
moderately high (0.06 to 0.20 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: Moderate (about 8.3 inches)
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Custom Soil Resource Report
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 2e
Hydrologic Soil Group: C
Ecological site: F136XY72ONC -Basic upland forest, moist
Hydric soil rating: No
Minor Components
Picture, undrained
Percent of map unit: 1 percent
Landform: Imerfluves
Landform position (two-dimensional): Summit
Down -slope shape: Convex
Across -slope shape: Convex
Hydric soil rating: Yes
GeB—Georgeville silt loam, 2 to 6 percent slopes
Map Unit Setting
National map unit symbol: 2vy6v
Elevation: 160 to 820 feet
Mean annual precipitation: 43 to 47 inches
Mean annual air temperature: 57 to 61 degrees F
Frost -free period: 200 to 230 days
Farmland classification: All areas are prime farmland
Map Unit Composition
Georgeville and similar soils: 90 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Georgeville
Setting
Landform: Imerfluves
Landform position (two-dimensional): Summit, shoulder
Landform position (three-dimensional): Interfluve
Down -slope shape: Convex
Across -slope shape: Convex
Parent material: Residuum weathered from metavolcanics and/or residuum
weathered from argillite and/or residuum weathered from phyllite and/or
residuum weathered from sericite schist
Typical profile
Ap - 0 to 9 inches: silt
loam
E - 9 to 14 inches: silt
loam
Bt1 - 14 to 20 inches:
silty clay loam
Bt2 - 20 to 27 inches:
clay
Bt3 - 27 to 49 inches:
silty clay
BCt - 49 to 57 inches:
silty clay loam
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Custom Soil Resource Report
C - 57 to 62 inches: silt loam
Properties and qualities
Slope: 2 to 6 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Well drained
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high
(0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: Moderate (about 9.0 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 2e
Hydrologic Soil Group: B
Ecological site: F136XY820GA - Acidic upland forest, moist
Hydric soil rating: No
GeC—Georgeville silt loam, 6 to 10 percent slopes
Map Unit Setting
National map unit symbol: 2vy6n
Elevation: 160 to 820 feet
Mean annual precipitation: 43 to 47 inches
Mean annual air temperature: 57 to 61 degrees F
Frost -free period: 200 to 230 days
Farmland classification: Farmland of statewide importance
Map Unit Composition
Georgeville and similar soils: 90 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Georgeville
Setting
Landform: Hillslopes
Landform position (two-dimensional): Shoulder, backslope
Landform position (three-dimensional): Side slope
Down -slope shape: Convex
Across -slope shape: Convex
Parent material: Residuum weathered from metavolcanics and/or residuum
weathered from argillite and/or residuum weathered from phyllite and/or
residuum weathered from sericite schist
Typical profile
Ap - 0 to 7 inches: silt loam
BE - 7 to 10 inches: silty clay loam
Bt - 10 to 44 inches: clay
BC - 44 to 53 inches: silty clay loam
C - 53 to 80 inches: loam
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Custom Soil Resource Report
Properties and qualities
Slope: 6 to 10 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Well drained
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high
(0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: High (about 9.2 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: B
Ecological site: F136XY820GA - Acidic upland forest, moist
Hydric soil rating: No
HrB—Herndon silt loam, 2 to 6 percent slopes
Map Unit Setting
National map unit symbol: 2rkjn
Elevation: 70 to 980 feet
Mean annual precipitation: 39 to 47 inches
Mean annual air temperature: 55 to 63 degrees F
Frost -free period: 200 to 250 days
Farmland classification: All areas are prime farmland
Map Unit Composition
Herndon and similar soils: 90 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Herndon
Setting
Landform: I me rfluves
Landform position (two-dimensional): Summit
Landform position (three-dimensional): Interfluve
Down -slope shape: Convex
Across -slope shape: Convex
Parent material: Residuum weathered from phyllite
Typical profile
Ap - 0 to 8 inches: silt loam
Bt1 - 8 to 12 inches: silty clay loam
Bt2 - 12 to 44 inches: clay
C - 44 to 80 inches: silt loam
Properties and qualities
Slope: 2 to 6 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Well drained
W

Custom Soil Resource Report
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high
(0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Maximum salinity. Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm)
Available water supply, 0 to 60 inches: Moderate (about 8.9 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 2e
Hydrologic Soil Group: B
Ecological site: F136XY820GA - Acidic upland forest, moist
Hydric soil rating: No
HrC—Herndon silt loam, 6 to 10 percent slopes
Map Unit Setting
National map unit symbol. 3tgx
Elevation: 320 to 700 feet
Mean annual precipitation: 37 to 60 inches
Mean annual air temperature: 59 to 66 degrees F
Frost -free period: 200 to 240 days
Farmland classification: Farmland of statewide importance
Map Unit Composition
Herndon and similar soils: 80 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Herndon
Setting
Landform: Hillslopes on ridges
Landform position (two-dimensional): Summit, shoulder
Landform position (three-dimensional): Side slope
Down -slope shape: Linear
Across -slope shape: Convex
Parent material: Residuum weathered from metavolcanics and/or argillite
Typical profile
Ap - 0 to 3 inches: silt loam
E - 3 to 9 inches: silt loam
Bt1 - 9 to 14 inches: silty clay loam
Bt2 - 14 to 34 inches: silty clay
BC - 34 to 48 inches: silty clay loam
C - 48 to 80 inches: silt loam
Properties and qualities
Slope: 6 to 10 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Well drained
Runoff class: Medium
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Custom Soil Resource Report
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high
(0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: Moderate (about 7.4 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: B
Ecological site: F136XY820GA - Acidic upland forest, moist
Hydric soil rating: No
Lg—Lignum silt loam, 0 to 3 percent slopes
Map Unit Setting
National map unit symbol: 3tr2
Elevation: 200 to 1,400 feet
Mean annual precipitation: 37 to 60 inches
Mean annual air temperature: 59 to 66 degrees F
Frost -free period: 200 to 240 days
Farmland classification: Farmland of statewide importance
Map Unit Composition
Lignum and similar soils: 85 percent
Minor components: 2 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Lignum
Setting
Landform: Imerfluves
Landform position (two-dimensional): Summit
Landform position (three-dimensional): Interfluve
Down -slope shape: Convex
Across -slope shape: Linear
Parent material: Residuum weathered from metavolcanics and/or residuum
weathered from argillite
Typical profile
A - 0 to 2 inches: silt loam
E - 2 to 12 inches: silt loam
Bt - 12 to 39 inches: silty clay
C - 39 to 56 inches: silt loam
Cr - 56 to 80 inches: weathered bedrock
Properties and qualities
Slope: 0 to 3 percent
Depth to restrictive feature: 40 to 60 inches to paralithic bedrock
Drainage class: Moderately well drained
Runoff class: Medium
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Custom Soil Resource Report
Capacity of the most limiting layer to transmit water (Ksat): Very low to moderately
low (0.00 to 0.06 in/hr)
Depth to water table: About 12 to 30 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: Moderate (about 8.2 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 2w
Hydrologic Soil Group: D
Ecological site: F136XY810SC - Acidic upland forest, seasonally wet
Hydric soil rating: No
Minor Components
Wehadkee, undrained
Percent of map unit. 2 percent
Landform: Depressions on flood plains
Down -slope shape: Concave
Across -slope shape: Linear
Hydric soil rating: Yes
Or —Orange silt loam, 0 to 3 percent slopes
Map Unit Setting
National map unit symbol: 3tr5
Elevation: 700 to 2,000 feet
Mean annual precipitation: 40 to 48 inches
Mean annual air temperature: 50 to 59 degrees F
Frost -free period: 160 to 190 days
Farmland classification: Farmland of statewide importance
Map Unit Composition
Orange and similar soils: 90 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Orange
Setting
Landform: I me rfluves
Landform position (two-dimensional): Summit
Landform position (three-dimensional): Interfluve
Down -slope shape: Linear
Across -slope shape: Linear
Parent material: Residuum weathered from monzonite and/or igneous and
metamorphic rock
Typical profile
A - 0 to 5 inches: silt loam
Bt - 5 to 24 inches: silty clay
29

Custom Soil Resource Report
C - 24 to 42 inches: silt loam
Cr - 42 to 80 inches: weathered bedrock
Properties and qualities
Slope: 0 to 3 percent
Depth to restrictive feature: 40 to 60 inches to paralithic bedrock
Drainage class: Moderately well drained
Runoff class: Low
Capacity of the most limiting layer to transmit water (Ksat): Very low to moderately
low (0.00 to 0.06 in/hr)
Depth to water table: About 12 to 36 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: Moderate (about 6.8 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 4w
Hydrologic Soil Group: D
Ecological site: F136XY710NC - Basic upland hardpan woodland, seasonally wet
and seasonally dry
Hydric soil rating: No
30

References
American Association of State Highway and Transportation Officials (AASHTO).
2004. Standard specifications for transportation materials and methods of sampling
and testing. 24th edition.
American Society for Testing and Materials (ASTM). 2005. Standard classification of
soils for engineering purposes. ASTM Standard D2487-00.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of
wetlands and deep -water habitats of the United States. U.S. Fish and Wildlife
Service FWS/OBS-79/31.
Federal Register. July 13, 1994. Changes in hydric soils of the United States.
Federal Register. September 18, 2002. Hydric soils of the United States.
Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric
soils in the United States.
National Research Council. 1995. Wetlands: Characteristics and boundaries.
Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service.
U.S. Department of Agriculture Handbook 18. http://www.nres.usda.gov/wps/portal/
n res/d eta i I/n ati o n a I/s o i Is/?cid = n res 142 p2_0 54262
Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for
making and interpreting soil surveys. 2nd edition. Natural Resources Conservation
Service, U.S. Department of Agriculture Handbook 436. http://
www. nres. usda.gov/wps/portal/nres/detail/national/soils/?cid=nres142p2_053577
Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of
Agriculture, Natural Resources Conservation Service. http://
www. nres. usda.gov/wps/portal/nres/detail/national/soils/?cid=nres142p2_053580
Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and
Delaware Department of Natural Resources and Environmental Control, Wetlands
Section.
United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of
Engineers wetlands delineation manual. Waterways Experiment Station Technical
Report Y-87-1.
United States Department of Agriculture, Natural Resources Conservation Service.
National forestry manual. http://www.nres.usda.gov/wps/portal/nres/detail/soils/
home/?cid=nres142p2_053374
United States Department of Agriculture, Natural Resources Conservation Service.
National range and pasture handbook. http://www.nres.usda.gov/wps/portal/nres/
detail/national/landuse/rangepastu re/?cid=stelprdb1043084
31

Custom Soil Resource Report
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430-VI. http://www.nres.usda.gov/wps/portal/
n res/d eta i I/so i Is/scie ntists/?cid=n res 142 p2_054242
United States Department of Agriculture, Natural Resources Conservation Service.
2006. Land resource regions and major land resource areas of the United States,
the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook
296. http://www.nres.usda.gov/wps/portal/nres/detail/national/soils/?
cid = n res 142 p2_05 3624
United States Department of Agriculture, Soil Conservation Service. 1961. Land
capability classification. U.S. Department of Agriculture Handbook 210. http:H
www.nrcs.usda.gov/lnternet/FSE—DOCUMENTS/nrcsl 42p2_052290. pdf
32

9/27/23, 10:23 AM Precipitation Frequency Data Server
NOAA Atlas 14, Volume 2, Version 3
Location name: Raleigh, North Carolina, USA*
Latitude: 35.8778°, Longitude:-78.6545° . . �3
Elevation: m/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 I PF graphical I Maps & aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1
Average recurrence interval (years)
Duration 1 100 1 2 5 10 25 50 00 200 500 1000
5-min 0.400 0.467 0.536 0.596 0.658 0.704 0.746 0.780 0.819 0.850
(0.367-0.437) (0.428-0.510) (0.492-0.585) (0.546-0.650) (0.601-0.71 7) (0.640-0.767) (0.673-0.811) (0.701-0.851) (0.730-0.893) (0.751-0.£
0.639
0.746
0.858
0.954
1.05
1.12
1.18
1.24
1.30
1.34
10-min
(0.586-0.698)
(0.685-0.816)
(0.789-0.937)
(0.874-1.04)
(0.957-1.14)
1 (1.02-1.22)
1 (1.07-1.29)
1 (1.11-1.35)
1 (1.15-1.41)
11 (1.18-1.46)
0.799
0.938
1.09
1.21
1.33
1.42
1.50
1.56
1.63
1.68
15-min
(0.732-0.872)
(0.861-1.02)
(0.998-1.18)
11 (1.10-1.31) 11
(1.21-1.45)
1 (1.29-1.55)
1 (1.35-1.63)
1 (1.40-1.70)
1 (1.45-1.78)
11 (1.48-1.84)
1.10
1.30
1.54
1.75
1.97
2.14
2.29
2.43
2.59
2.72
30-min
(1.00-1.20)
1 (1.19-1.42)
11 (1.42-1.68)
11 (1.60-1.90) 11
(1.80-2.15)
1 (1.94-2.33)
1 (2.07-2.50)
1 (2.18-2.65)
1 (2.31-2.83)
11 (2.40-2.97)
1.36
1.63
1.98
2.28
2.62
2.90
3.16
3.41
3.72
3.97
60-min
(1.25-1.49)
1 (1.49-1.78)
11 (1.82-2.16)
11 (2.08-2.48) 11
(2.39-2.86)
1 (2.63-3.16)
1 (2.85-3.44)
1 (3.06-3.71)
1 (3.32-4.06)
11 (3.51-4.34)
1.59
1.90
2.33
2.71
3.16
3.54
3.89
4.25
4.71
6.09
2-hr
(1.45-1.75)
1 (1.74-2.08)
11 (2.13-2.56)
11 (2.46-2.97) 11
(2.85-3.46)
1 (3.18-3.87)
1 (3.48-4.26)
1 (3.78-4.65)
1 (4.15-5.15)
11 (4.44-5.58)
1.68
2.01
2.48
2.90
3.42
3.87
4.30
4.75
5.34
5.85
3-hr
(1.54-1.85)
1 (1.84-2.22)
11 (2.26-2.73)
11 (2.64-3.18) 11
(3.09-3.74)
1 (3.47-4.23)
1 (3.83-4.70)
1 (4.20-5.18)
1 (4.68-5.84)
11 (5.06-6.40)
2.03
2.43
2.99
3.50
4.15
4.70
5.25
5.82
6.60
7.26
6-hr
(1.86-2.23)
1 (2.23-2.66)
11 (2.74-3.28)
11 (3.20-3.82) 11
(3.76-4.52)
1 (4.24-5.12)
1 (4.70-5.71)
1 (5.15-6.32)
1 (5.76-7.16)
11 (6.26-7.89)
2.40
2.87
3.55
4.18
4.99
5.69
6.40
7.15
8.18
9.08
12-hr
(2.20-2.62)
1 (2.64-3.14)
11 (3.26-3.88)
11 (3.82-4.56) 11
(4.53-5.42)
1 (5.12-6.16)
1 (5.71-6.93)
1 (6.30-7.73)
1 (7.09-8.84)
11 (7.75-9.81)
2.85
3.44
4.31
5.00
5.93
6.67
7.42
8.19
9.25
10.1
24-hr
(2.66-3.07)
1 (3.22-3.70)
11 (4.02-4.64)
11 (4.66-5.37) 11
(5.50-6.37)
1 (6.17-7.16)
1 (6.85-7.97)
1 (7.54-8.81)
1 (8.48-9.95)
11 (9.20-10.9)
3.30
3.97
4.94
5.70
6.72
7.52
8.34
9.18
10.3
11.2
2{iay
(3.08-3.55)
1 (3.71-4.28)
11 (4.60-5.32)
11 (5.30-6.12) 11
(6.23-7.22)
1 (6.96-8.09)
1 (7.69-8.97)
1 (8.44-9.88)
1 (9.44-11.1)
11 (10.2-12.1)
3.50
4.20
5.20
5.99
7.05
7.89
8.74
9.62
10.8
11.7
3tlay
(3.27-3.75)
1 (3.93-4.51)
11 (4.86-5.58)
11 (5.58-6.41) 11
(6.55-7.56)
1 (7.31-8.46)
1 (8.08-9.38)
1 (8.86-10.3)
1 (9.91-11.6)
11 (10.7-12.7)
3.70
4.43
5.46
6.27
7.38
8.26
9.15
10.1
11.3
12.3
4tlay
(3.46-3.96)
1 (4.15-4.74)
11 (5.11-5.84)
11 (5.86-6.70) 11
(6.86-7.89)
1 (7.66-8.83)
1 (8.46-9.79)
1 (9.28-10.8)
1 (10.4-12.1)
11 (11.2-13.2)
4.28
5.11
6.22
7.10
8.30
9.25
10.2
11.2
12.6
13.6
7{iay
(4.02-4.57)
1 (4.79-5.45)
11 (5.83-6.63)
11 (6.64-7.57) 11
(7.74-8.85)
1 (8.61-9.87)
1 (9.48-10.9)
(10.4-12.0)
1 (11.6-13.5)
11 (12.5-14.6)
4.87
5.79
6.96
7.88
9.12
10.1
11.1
12.1
13.4
14.4
10tlay
(4.58-5.20)
(5.44-6.18)
(6.54-7.42)
(7.39-8.39)
(8.52-9.72)
1 (9.41-10.8)
1 (10.3-11.8)
(11.2-12.9)
1 (12.4-14.4)
11 (13.3-15.5)
6.53
7.70
9.10
10.2
11.7
12.9
14.1
15.3
16.9
18.2
20tlay
(6.14-6.95)
(7.25-8.20)
(8.55-9.69)
(9.58-10.9)
(11.0-12.5)
1 (12.0-13.7)
1 (13.1-15.0)
1 (14.2-16.3)
1 (15.6-18.1)
11 (16.7-19.5)
8.10
9.53
11.1
12.3
13.9
15.1
16.3
17.5
19.1
20.3
30tlay
(7.64-8.60)
1 (8.98-10.1)
(10.4-11.8)
(11.6-13.0) 11
(13.0-14.7)
1 (14.1-16.0)
1 (15.2-17.3)
1 (16.3-18.7)
1 (17.8-20.4)
11 (18.8-21.7)
10.3
12.1
13.8
15.2
17.0
18.3
19.6
20.9
22.6
23.8
45tlay
(9.81-10.9)
1 (11.5-12.8)
(13.1-14.6)
11 (14.4-16.0) 11
(16.0-17.9)
1 (17.3-19.3)
1 (18.4-20.7)
1 (19.6-22.1)
1 (21.1-23.9)
11 (22.2-25.3)
12.4
14.5
16.3
17.8
19.7
21.1
22.4
23.7
25.4
26.7
60tlay
(11.8-13.0)
(13.8-15.2)
(15.5-17.2)
(16.9-18.7)
(18.6-20.7)
(19.9-22.2)
(21.2-23.7)
(22.4-25.1)
(23.9-26.9)
(25.1-28.3)
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 NOAAAtlas 14 document for more information.
Back to Top
PF graphical
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9/27/23, 10:23 AM
Precipitation Frequency Data Server
25
20
til
25
5 20
t
Q
a
15
0
a 10
u
a
5
PD5-teased depth -duration -frequency (DDF) curves
Latitude: 35.8778°, Longitude:-78.6545'
C C C CC C = r ra M M M M M
u�5 O E N f>'7 6 N N f>li , O CD 6 i O
Duration � N rn v Ia
1 2 5 10 25 50 100 20D 500 1000
Average recurrence interval (years)
NOAA Atlas 14, Volume 2, Version 3 Created (GMT}_ Wed Sep 27 L4:23-06 2023
Back to Top
Maps & aerials
Small scale terrain
Average recurrence
ml erva I
{years}
— 1
2
— 5
10
— 25
50
100
200
500
1000
Duration
— 6-min —
2-day
— 10-min —
3-day
15-min —
d-dmy
— 30-min —
7-day
— 6 Wain —
10-day
— 2fir —
20-day
— 3-fir —
30-day
— Sfir —
45-day
— 12-h r —
60-day
- 24-hr
https://hdsc.nws.noaa.gov/pfds/pfds_printpage.htm1?lat=35.8778&Ion=-78.6545&data=depth&units=engIish&series=pds 2/4

9/27/23, 10:23 AM Precipitation Frequency Data Server
MW
r_
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Urn
# • Durham I
Rocky Mount
Greensboro ,.
T H C A R O L I N A • Greenville
Charlotte
ettf•villz • —
100km Jacksonville
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Large scale map
/ Nn
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Rocky Mount
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.o North Greenville
Carolina
arlotte
Fayetteville —
100km Ja-ksonviffe
6 mi
Large scale aerial
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Precipitation Frequency Data Server
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US Department of Commerce
National Oceanic and Atmospheric Administration
National Weather Service
National Water Center
1325 East West Highway
Silver Spring, MD 20910
Questions?: [e-mail]
Disclaimer
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HYDROLOGY - NRCS CURVE NUMBER
Project Name:
1102 Old English Ct
Project Number:
55441.002
Location:
RALEIGH, NC
Date:
5/25/2023
Prepared by:
JeffYokley, EIT
Checked by:
David Duncan, PE
Existing or Proposed:
Existing
Catchment:
DA-1
TOTAL
COVER DESCRIPTION
open Npace (iawns, parKs, got courses, etc.)
on (<5016 gra
Fair Condition (50% to 75% grass cover)
Good Condition (>75% grass cover)
Impervious Areas
Paved parking lots, roofs, driveways, etc.
Streets and roads:
Paved; curbs and storm sewers
Paved; open ditches
Gravel
Dirt
Urban Districs
Commerica ass
Industrial
Residential districts by average lot size:
1/8 acre or less (town houses)
1/4 acre
1/3 acre
1/2 acre
1 acre
2 acre
Developing Urban Areas
Newly graded areas
Pasture (<50% ground cover or heavily grazed)
Pasture (50% to 75% ground cover or not heavily grazed)
Pasture (>75% ground cover or lightly grazed)
Meadow - continuous grass, protected from grazing and
generally mowed for hay
Brush (<50% ground cover)
Brush (50% to 75% ground cover)
Brush (>75% ground cover)
Woods (Forest litter, small trees, and brush destroyed by heavy
grazing or regular burning)
Woods (Woods are grazed but not burned, and some forest litter
covers the soil)
Woods (Woods
adequately cove
TOTAL(AC
TIMMONS GROUP
YOUR VISION ACHIEVED THROUGH OURS,
AREA
TOTAL HSG 'A' HSG 'B' HSG 'C' HSG 'D'
(AC) (SQ.FT.) (SQ.FT.) (SQ.FT.) (SQ.FT.)
15.29 83943 355757 0 226512
0.00 0 0 0 0
0.00 0 0 0 0
0 0 0 0
0.00 0 0 0 0
0 0 0 0
0.00 0 0 0 0
0.00 0 0 0 0
0.00 0 0 0 0
0.00 0 0 0 0
0 0 0 0
77.05 422903 1792302 0 1141166
0.00 0 0 0 0
0 0 0 0
61.70 338671 1435320 0 913874
171.64 942058 3992533 0 2542062
0.00 0 0 0 0
0.00 0 0 0 0
0.00 0 1 0 0 0
0.00 0 0 0 0
0 0 0 0
0.00 0 0 0 0
0.00 0 0 0 0
0.00 0 0 0 0
0.00 0 0 0 0
0.00 0 0 0 0
0.00 0 0 0 0
0.00 0 0 0 0
0.00 0 0 0 0
0.00 0 0 0 0
0.00 0 0 0 0
35.80 196500 832787 0 530239
361.49 1 45.55 1 193.04 1 0.00 1 122.91
TIMMONS GROUP

111. SCS CURVE NUMBER CALCULATION
COVER DESCRIPTION (Source: NCDEQ Stormwater MDC)
SCS CN
HSG 'A'
HSG 'B'
HSG 'C'
HSG 'D'
Open Space (lawns, parks, golf courses, etc.)
Poor Condition (<50% grass cover)
68
79
86
89
Fair Condition (50% to 75% grass cover)
49
69
79
84
Good Condition (>75% grass cover)
39
61
74
80
Impervious Areas
Paved parking lots, roofs, driveways, etc.
98
98
98
98
Streets and roads:
Paved; curbs and storm sewers
98
98
98
98
Paved; open ditches
83
89
98
98
Gravel
76
85
89
91
Dirt
72
82
85
88
Urban Districs
Commerical and business
89
92
94
95
Industrial
81
88
91
93
Residential districts by average lot size:
1/8 acre or less (town houses)
77
85
90
92
1/4 acre
61
75
83
87
1/3 acre
57
72
81
86
1/2 acre
54
70
80
85
1 acre
51
68
79
84
2 acre
46
65
77
82
Developing Urban Areas
Newly graded areas
77
86
91
94
Pasture (<50% ground cover or heavily grazed)
68
79
86
89
Pasture (50% to 75% ground cover or not heavily grazed)
49
69
79
84
Pasture (>75% ground cover or lightly grazed)
39
61
74
80
Meadow - continuous grass, protected from grazing and generally mowed for
hay
30
58
71
78
Brush (<50% ground cover)
48
67
77
83
Brush (50% to 75% ground cover)
35
56
70
77
Brush (>75% ground cover)
30
48
65
73
Woods (Forest litter, small trees, and brush destroyed by heavy grazing or
regular burning)
45
66
77
83
Woods (Woods are grazed but not burned, and some forest litter covers the
soil)
36
60
73
79
Woods (Woods are protected from grazing, and litter and brush adequately
cover the soil)
30
55
70
77
3048
15157
0
10896
COMPOSITE SCS CN
% Im pervious
TIMMONS GROUP

BASIN AVERAGE SLOPE WORKSHEET
Project Name:
1102 Old English Ct
Project Number:
55441.009
Prepared By:
Jeff Yokely, El
Checked By:
Alston Willard, El
Date:
5/26/2023
AVERAGE
SLOPEBASIN •
Basin (y)
Hydraulic
Stor. Cap.
Avg Slope
Catchment
Area (Ac)
A (Sq MI)
CN
Length HL
Tlag (hr)
Tlag (min)
Tc (min)
( )
%
(Ft)
DA-1
361.49
0.56483
""
9162
2.35
0.75
45.2
75.3
Conv. Ac to Sq mi.
640
ac/sqmi
S= 1000/CN - 10
T lag = H LA0.8 * (S+1)A0.7 / 1900* yA0.5
Tc=Tlag/ 0.6
NOTES:
* CN estimates based on
Soil Survey of Wake County, North Carolina
, USDA Web Soils Survey
*Runoff curve numbers found in NCDEQ MDC
* Areas taken from watershed
delineations with NC FRIS Topo Data obtained May, 2023
* Hydraulic lengths and basin average slopes measured from above
referenced topo maps
* T-lag SCS Method "Hydrology and Floodplain Analysis", Addison Wesley Pg. 128
AVERAGE
SLOPEBASIN
Sample Line
Length US Elev DS Elev
Slope
1
988 488 442
0.0466
2
632 473 428
0.0709
3
1129 453 407
0.0412
4
1352 437 349
0.0652
5
1323 414 324
0.0680
6
667 372 302
0.1044
7
737 460 414
0.0626
8
1868 448 360
0.0470
9
1923 433 334
0.0513
10
1695 410 314
0.0561
Final Weighted Avg
12313.8
0.0579
Page 1

TOC - Basin Avg Slope
Subcat Reach on Link

1100 Old Engligh Court
Prepared by Timmons Group Printed 9/27/2023
HydroCAD® 10.10-7a s/n 08663 © 2021 HydroCAD Software Solutions LLC Page 2
Area Listing (all nodes)
Area CN Description
(acres) (s u bcatch me nt-n u m be rs)
361.500 81 Commerical, 1/8 acre, 1/4 acre, woods land uses (3S)
361.500 81 TOTAL AREA

1100 Old Engligh Court Type 1124-hr 100-yr Rainfall=7.42"
Prepared by Timmons Group Printed 9/27/2023
HydroCAD® 10.10-7a s/n 08663 © 2021 HydroCAD Software Solutions LLC Page 3
Summary for Subcatchment 3S: TOC - Basin Avg Slope
Runoff = 847.60 cfs @ 12.81 hrs, Volume= 143.047 af, Depth> 4.75"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
Type II 24-hr 100-yr Rainfall=7.42"
Area (ac) CN Description
361.500 81 Commerical, 1/8 acre, 1/4 acre, woods land uses
361.500 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
75.3 9,162 2.03 Direct Entry, TOC
Subcatchment 3S: TOC - Basin Avg Slope
Hydrograph
■ Runoff
Time (hours)

1100 Old Engligh Court Table of Contents
Prepared by Timmons Group Printed 9/27/2023
HydroCAD® 10.10-7a s/n 08663 © 2021 HydroCAD Software Solutions LLC
TABLE OF CONTENTS
Project Reports
1 Routing Diagram
2 Area Listing (all nodes)
100-yr Event
3 Subcat 3S: TOC - Basin Avg Slope

9/27/23, 10:20 AM
StreamStats
StreamStats Report
Region ID: NC
Workspace ID: NC20230927141039149000
Clicked Point (Latitude, Longitude): 35.87744,-78.65335
Time: 2023-09-27 10:11:17 -0400
At B
e
U
n
u
r Mine''
Basin Characteristics
C�
- nm-c
�dr F 7—
torso,
Pl�
N-
T
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II
r
F�
O Collapse All
Parameter Code
Parameter Description
Value
Unit
DRNAREA
Area that drains to a point on a stream
0.58
square miles
LC061MP
Percentage of impervious area determined from
NLCD 2006 impervious dataset
20.24
percent
PCTREG1
Percentage of drainage area located in Region 1
- Piedmont / Ridge and Valley
100
percent
PCTREG2
Percentage of drainage area located in Region 2
- Blue Ridge
0
percent
PCTREG3
Percentage of drainage area located in Region 3
- Sandhills
0
percent
PCTREG4
Percentage of drainage area located in Region 4
- Coastal Plains
0
percent
PCTREG5
Percentage of drainage area located in Region 5
- Lower Tifton Uplands
0
percent
General Disclaimers
Parameter values have been edited, computed flows may not apply.
https://streamstats.usgs.gov/ss/ 1 /5

9/27/23, 10:20 AM
Peak -Flow Statistics
StreamStats
Peak -Flow Statistics Parameters [Region 1 Piedmont rural under 1 sgmi 2014 5030]
Parameter Code
Parameter Name
Value
Units
Min Limit
Max Limit
DRNAREA
Drainage Area
0.58
square miles
0.1
1
LC061MP
Percent Impervious NLCD2006
20.24
percent
0
47.9
Peak -Flow Statistics Parameters [Peak Southeast US NC 2023 5006]
Parameter Code
Parameter Name
Value
Units
Min Limit
Max Limit
PCTREG1
Percent Area in Region 1
100
percent
0
100
PCTREG2
Percent Area in Region 2
0
percent
0
100
PCTREG3
Percent Area in Region 3
0
percent
0
100
PCTREG5
Percent Area in Region 5
0
percent
0
100
DRNAREA
Drainage Area
0.58
square miles
0.08
8902
PCTREG4
Percent Area in Region 4
0
percent
0
100
Peak -Flow Statistics Flow Report [Region 1 Piedmont rural under 1 sgmi 2014 50301
PII: Prediction Interval -Lower, Plu: Prediction Interval -Upper, ASEp: Average Standard Error of Prediction, SE: Standard
Error (other -- see report)
Statistic
Value
Unit
PII
Plu
ASEp
50-percent AEP flood
206
ft^3/s
111
381
31.9
20-percent AEP flood
298
ft^3/s
182
489
25.4
10-percent AEP flood
360
ft^3/s
224
579
25
4-percent AEP flood
435
ft^3/s
259
731
27
2-percent AEP flood
488
ft^3/s
278
855
29.3
1-percent AEP flood
544
ft^3/s
293
1010
32.1
0.5-percent AEP flood
596
ft^3/s
305
1160
35.1
0.2-percent AEP flood
670
ft^3/s
328
1 370
37.5
Peak -Flow Statistics Flow Report [Peak Southeast US NC 2023 5006]
PII: Prediction Interval -Lower, Plu: Prediction Interval -Upper, ASEp: Average Standard Error of Prediction, SE: Standard
Error (other -- see report)
Statistic
Value
Unit
PII
Plu
ASEp
50-percent AEP flood
105
ft^3/s
57.6
191
36.8
20-percent AEP flood
189
ft^3/s
106
336
35.8
10-percent AEP flood
257
ft^3/s
144
460
36.3
4-percent AEP flood
351
ft^3/s
188
655
38.4
2-percent AEP flood
435
ft^3/s
231
819
39.8
1-percent AEP flood
519
ft^3/s
270
999
41.3
0.5-percent AEP flood
605
ft^3/s
307
1190
42.8
0.2-percent AEP flood
719
ft^3/s
357
1450
44.4
https://streamstats.usgs.gov/ss/ 2/5

9/27/23, 10:20 AM StreamStats
Peak -Flow Statistics Citations
Feaster, T.D., Gotvald, A.J., and Weaver, J.C.,2014, Methods for estimating the magnitude and frequency of floods for
urban and small, rural streams in Georgia, South Carolina, and North Carolina, 2011 (ver. 1.1, March 2014): U.S.
Geological Survey Scientific Investigations Report 2014-5030, 104 p. (http://pubs.usgs.gov/sir/2014/5030/)
Feaster, T.D., Gotvald, A.J., Musser, J.W., Weaver, J.C, Kolb, K.R., Veilleux, A.G., and Wagner, D.M.2023, Magnitude
and frequency of floods for rural streams in Georgia, South Carolina, and North Carolina, 2017—Results: U.S.
Geological Survey Scientific Investigations Report 2023-5006, 75 p.
(https:Hpubs.er.usgs.gov/publication/sir20235006)
Bankfull Statistics
Bankfull Statistics Parameters [Appalachian Highlands D Bieger 2015]
Parameter Code Parameter Name Value Units Min Limit Max Limit
DRNAREA Drainage Area 0.58 square miles 0.07722 940.1535
Bankfull Statistics Parameters [Piedmont P Bieger 20151
Parameter Code Parameter Name
DRNAREA Drainage Area
Bankfull Statistics Parameters [USA Bieger 2015]
Parameter Code Parameter Name
DRNAREA Drainage Area
Value Units Min Limit Max Limit
0.58 square miles 0.289575 939.99906
Value Units Min Limit Max Limit
0.58 square miles 0.07722 59927.7393
Bankfull Statistics Flow Report [Appalachian Highlands D Bieger 2015]
Statistic Value Unit
Bieger_D_channel_width 12.1 ft
Bieger_D_channel_depth 0.959 ft
Bieger_D_channel_cross_sectional_area 11.8 ft^2
Bankfull Statistics Flow Report [Piedmont P Bieger 20151
Statistic
Value
Unit
Bieger_P_channel_width
11
ft
Bieger_P_channel_depth
0.968
ft
Bieger_P_channel_cross_sectional_area
10.4
ft^2
Bankfull Statistics Flow Report [USA Bieger 2015]
Statistic
Value
Unit
Bieger-USA-channel-width
10.2
ft
Bieger-USA-channel-depth
1.07
ft
Bieger-USA-channel-cross-sectional-area
12.7
ft^2
https://streamstats.usgs.gov/ss/ 3/5

9/27/23, 10:20 AM StreamStats
Bankfull Statistics Flow Report [Area -Averaged]
Statistic
Value
Unit
Bieger_D_channel_width
12.1
ft
Bieger_D_channel_depth
0.959
ft
Bieger_D_channel_cross_sectional_area
11.8
ft^2
Bieger_P_channel_width
11
ft
Bieger_P_channel_depth
0.968
ft
Bieger_P_channel_cross_sectional_area
10.4
ft^2
Bieger_USA_channel_width
10.2
ft
Bieger_USA_channel_depth
1.07
ft
Bieger_USA_channel_cross_sectional_area
12.7
ft^2
Bankfull Statistics Citations
Bieger, Katrin; Rathjens, Hendrik; Allen, Peter M.; and Arnold, Jeffrey G.,2015, Development and Evaluation of
Bankfull Hydraulic Geometry Relationships for the Physiographic Regions of the United States, Publications from
USDA-ARS / UNL Faculty, 17p. (https:Hdigitalcommons.uni.edu/usdaarsfacpub/1515?
utm-source=digitalcommons.unl.edu%2Fusdaarsfacpub%2F1515&utm-medium=PDF&utm-campaign=PDFCoverPages)
Urban Peak -Flow Statistics
Urban Peak -Flow Statistics Parameters [Region 1 Piedmont Urban under 3 sgmi 2014 5030]
Parameter Code
Parameter Name
Value
Units
Min Limit
Max Limit
DRNAREA
Drainage Area
0.58
square miles
0.1
3
LC061MP
Percent Impervious NLCD2006
20.24
percent
0
47.9
Urban Peak -Flow Statistics Flow Report [Region 1 Piedmont Urban under 3 sgmi 2014 5030]
PII: Prediction Interval -Lower, Plu: Prediction Interval -Upper, ASEp: Average Standard Error of Prediction, SE: Standard
Error (other -- see report)
Statistic
Value
Unit
PII
Plu
ASEp
Urban 50-percent AEP flood
206
ft^3/s
111
381
31.9
Urban 20-Percent AEP flood
298
ft^3/s
182
489
25.4
Urban 10-percent AEP flood
360
ft^3/s
224
579
25
Urban 4-percent AEP flood
435
ft^3/s
259
731
27
Urban 2-percent AEP flood
488
ft^3/s
278
855
29.3
Urban 1-percent AEP flood
544
ft^3/s
293
1010
32.1
Urban 0.5-percent AEP flood
596
ft^3/s
305
1160
35.1
Urban 0.2-percent AEP flood
670
ft^3/s
328
1370
37.5
Urban Peak -Flow Statistics Citations
Feaster, T.D., Gotvald, A.J., and Weaver, J.C.,2014, Methods for estimating the magnitude and frequency of floods for
urban and small, rural streams in Georgia, South Carolina, and North Carolina, 2011 (ver. 1.1, March 2014): U.S.
Geological Survey Scientific Investigations Report 2014-5030, 104 p. (http://pubs.usgs.gov/sir/2014/5030/)
https://streamstats.usgs.gov/ss/ 4/5

9/27/23, 10:20 AM
Maximum Probable Flood Statistics
StreamStats
Maximum Probable Flood Statistics Parameters [Southeast US MPF abv FaIlLine small 2023 5006]
Parameter Code Parameter Name Value Units Min Limit Max Limit
DRNAREA Drainage Area 0.58 square miles 0.08 30
Maximum Probable Flood Statistics Parameters [Crippen Bue Region 21
Parameter Code Parameter Name Value Units Min Limit Max Limit
DRNAREA Drainage Area 0.58 square miles 0.1 3000
Maximum Probable Flood Statistics Flow Report [Southeast US MPF abv FaIlLine small 2023 5006]
Statistic Value Unit
Maximum Flood Southeastern US 1290 ft^3/s
Maximum Probable Flood Statistics Flow Report [Crippen Bue Region 21
Statistic Value Unit
Maximum Flood Crippen Bue Regional 3830 ft^3/s
Maximum Probable Flood Statistics Flow Report [Area -Averaged]
Statistic Value Unit
Maximum Flood Southeastern US 1290 ft^3/s
Maximum Flood Crippen Bue Regional 3830 ft^3/s
Maximum Probable Flood Statistics Citations
Crippen, J.R. and Bue, Conrad D.1977, Maximum Floodflows in the Conterminous United States, Geological Survey
Water -Supply Paper 1887, 52p. (https:Hpubs.usgs.gov/wsp/l887/report.pdf)
Feaster, T.D., Gotvald, A.J., Musser, J.W., Weaver, J.C, Kolb, K.R., Veilleux, A.G., and Wagner, D.M.2023, Magnitude
and frequency of floods for rural streams in Georgia, South Carolina, and North Carolina, 2017—Results: U.S.
Geological Survey Scientific Investigations Report 2023-5006, 75 p.
(https:Hpubs.er.usgs.gov/publication/sir20235006)
USGS Data Disclaimer: Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for
which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the
U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems,
nor shall the act of distribution constitute any such warranty.
USGS Software Disclaimer: This software has been approved for release by the U.S. Geological Survey (USGS). Although the software has been subjected to rigorous
review, the USGS reserves the right to update the software as needed pursuant to further analysis and review. No warranty, expressed or implied, is made by the
USGS or the U.S. Government as to the functionality of the software and related material nor shall the fact of release constitute any such warranty. Furthermore, the
software is released on condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from its authorized or unauthorized
use.
USGS Product Names Disclaimer: Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Application Version: 4.17.0
StreamStats Services Version: 1.2.22
NSS Services Version: 2.2.1
https://streamstats.usgs.gov/ss/ 5/5

APPENDIX B
HYDRAULICS
Floodplain Boundary Workmap
HEC-RAS Cross Sections
HEC-RAS Output Tables

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Existing Cross Sections

Floodplain Analysis Plan: Existing Conditions 10/12/2023
Geom: Existing Conditions Flow: 1 % Peak Flow
IRS = 330
306
0 1
4 2
Legend
5
EG 100-year
305
WS 100-year
■
Ground
304
Bank Sta
303
0
w
302
301
300
299
250 300 350 400 450 500
550
Station (ft)
Floodplain Analysis Plan: Existing Conditions 10/12/2023
Geom: Existing Conditions Flow: 1 % Peak Flow
IRS = 278
.1 �.12
320
0
4
Legend
5
EG 100-year
WS 100-year
315
■
Ground
•
Bank Sta
310
0
a�
w
305
-----------------------
300
295
250 300 350 400 450 500
550
Station (ft)

Floodplain Analysis Plan: Existing Conditions 10/12/2023
Geom: Existing Conditions Flow: 1 % Peak Flow
IRS = 244
.1 �.12
315
0
4
Legend
5
EG 100-year
WS 100-year
310
■
Ground
•
Bank Sta
0
.-
305
a�
w
--------------------------------------------------------------------------------------------------------------
300
295
250 300 350 400 450 500
550
Station (ft)
Floodplain Analysis Plan: Existing Conditions 10/12/2023
Geom: Existing Conditions Flow: 1 % Peak Flow
IRS = 222
1 T.045 .12
306
Legend
-------------------------
EG 100-year
WS 100-year
304
■
Ground
•
Bank Sta
302
0
40
a�
w
300
298
296
250 300 350 400 450 500
550
Station (ft)
2

Floodplain Analysis Plan: Existing Conditions 10/12/2023
Geom: Existing Conditions Flow: 1 % Peak Flow
IRS=177
1 "I<.045�� .12
308
Legend
-------------------------
EG 100-year
306
WS 100-year
■
Ground
•
Bank Sta
304
0
.-
302
a�
w
300
298
296
250 300 350 400 450 500 550
600
Station (ft)
Floodplain Analysis Plan: Existing Conditions 10/12/2023
Geom: Existing Conditions Flow: 1 % Peak Flow
IRS =146
1 >�<04.12
306
Legend
-------------------------
EG 100-year
WS 100-year
304
Crit 100-year
----------------------------------------------------------------------------------------------------
t
Ground
•
Bank Sta
302
0
a�
w
300
298
296
300 350 400 450 500 550
600
Station (ft)
3

Floodplain Analysis Plan: Existing Conditions 10/12/2023
Geom: Existing Conditions Flow: 1 % Peak Flow
IRS=104
1 "� .045 �� .12
306
Legend
-------------------------
EG 100-year
WS 100-year
304
■
Ground
•
Bank Sta
302
0
a�
w
300
298
296
350 400 450 500 550
600
Station (ft)
Floodplain Analysis Plan: Existing Conditions 10/12/2023
Geom: Existing Conditions Flow: 1 % Peak Flow
IRS
�
306
0
4
Legend
5
EG 100-year
WS 100-year
304
Crit 100-year
t
Ground
•
Bank Sta
302
0
a�
w
300
298
296
250 300 350 400 450 500 550
600
Station (ft)
4

Proposed Cross Sections

Floodplain Analysis Plan: Proposed Conditions 10/12/2023
Geom: Proposed Conditions Flow: 1 % Peak Flow - post
IRS = 308
306
0 1
4 2
Legend
5
EG 100-year
305
WS 100-year
Crit 100-year
304
Ground
•
Bank Sta
S
303
0
w
302
301
300
299
250 300 350 400 450 500
550
Station (ft)
Floodplain Analysis Plan: Proposed Conditions 10/12/2023
Geom: Proposed Conditions Flow: 1 % Peak Flow - post
IRS = 255
.1 �.12
320
0
4
Legend
5
EG 100-year
WS 100-year
315
Crit 100-year
t
Ground
•
Bank Sta
310
0
a�
w
305
----------------------------------------------------------------------------------------------------------------------------------
300
295
250 300 350 400 450 500
550
Station (ft)

31
31
w
Floodplain Analysis Plan: Proposed Conditions 10/12/2023
Geom: Proposed Conditions Flow: 1 % Peak Flow - post
IRS = 223
1 "I i .12
250 300 350 400 450 500 550
Station (ft)
Floodplain Analysis Plan: Proposed Conditions 10/12/2023
Geom: Proposed Conditions Flow: 1 % Peak Flow - post
IRS = 209
0
Legend
-------------------------
EG 100-year
WS 100-year
■
Ground
•
Bank Sta
045.12�
Legend
-------------------------
EG 100-year
WS 100-year
■
Ground
•
Bank Sta
250 300 350 400 450 500 550
Station (ft)
2

Floodplain Analysis Plan: Proposed Conditions 10/12/2023
Geom: Proposed Conditions Flow: 1 % Peak Flow - post
IRS=174
1 "' .045 �� .12
308
Legend
-------------------------
EG 100-year
306
WS 100-year
■
Ground
•
Bank Sta
304
0
.-
302
a�
w
300
298
296
250 300 350 400 450 500 550
600
Station (ft)
Floodplain Analysis Plan: Proposed Conditions 10/12/2023
Geom: Proposed Conditions Flow: 1 % Peak Flow - post
IRS =145
1 >�<04.12
306
Legend
-------------------------
EG 100-year
WS 100-year
304
Crit 100-year
t
Ground
•
Bank Sta
302
0
a�
w
300
298
296
300 350 400 450 500 550
600
Station (ft)
3

Floodplain Analysis Plan: Proposed Conditions 10/12/2023
Geom: Proposed Conditions Flow: 1 % Peak Flow - post
IRS=104
1 "� .045 �� .12
306
Legend
-------------------------
EG 100-year
WS 100-year
304
■
Ground
•
Bank Sta
302
0
a�
w
300
298
296
350 400 450 500 550
600
Station (ft)
Floodplain Analysis Plan: Proposed Conditions 10/12/2023
Geom: Proposed Conditions Flow: 1 % Peak Flow - post
IRS
�
306
0
4
Legend
5
EG 100-year
WS 100-year
304
Crit 100-year
t
Ground
•
Bank Sta
302
0
a�
w
300
298
296
250 300 350 400 450 500 550
600
Station (ft)
4

Existing Output Tables

HEC-RAS Plan: Exist River: Existing CL Reach: Existing Centerl Profile: 100-year
Reach
River Sta
Profile
Q Total
Min Ch El
W.S. Elev
Crit W.S.
E.G. Elev
E.G. Slope
Vel Chnl
Flow Area
Top Width
Froude # Chl
(cfs)
(ft)
(ft)
(ft)
(ft)
(ft/ft)
(ft/s)
(sq ft)
(ft)
Existing Centerl
330
100-year
848.00
299.22
303.51
304.00
0.009650
7.47
294.21
206.39
0.67
Existing Centerl
278
100-year
848.00
298.04
303.39
303.69
0.006148
6.36
364.41
207.31
0.52
Existing Centerl
244
100-year
848.00
297.00
303.24
303.58
0.004369
5.95
329.64
158.48
0.45
Existing Centerl
222
100-year
848.00
297.00
303.28
303.50
0.002424
4.53
387.11
171.96
0.34
Existing Centerl
177
100-year
848.00
297.00
303.18
303.42
0.003161
4.79
399.94
222.23
0.38
Existing Centerl
146
100-year
848.00
297.00
302.32
302.32
303.23
0.010267
8.56
198.27
130.68
0.69
Existing Centerl
104
100-year
848.00
296.70
301.85
302.28
0.003840
5.38
217.68
136.71
0.45
Existing Centerl
6
100-year
848.00
296.00
301.08
301.07
301.69
0.010013
7.76
270.90
209.15
0.65

Proposed Output Tables

HEC-RAS Plan: Proposed River: Proposed CL Reach: Proposed Center) Profile: 100-year
Reach
River Sta
Profile
Q Total
Min Ch El
W.S. Elev
Crit W.S.
E.G. Elev
E.G. Slope
Val Chnl
Flow Area
Top Width
Froude # Chl
(cfs)
(ft)
(ft)
(ft)
(ft)
(ft/ft)
(ft/s)
(sq ft)
(ft)
Proposed Center)
308
100-year
848.00
299.22
303.40
303.39
303.99
0.011497
8.01
272.48
203.40
0.73
Proposed Center)
255
100-year
848.00
298.04
303.00
302.93
303.57
0.011982
8.32
280.37
199.39
0.72
Proposed Center)
223
100-year
848.00
297.00
303.06
303.36
0.004250
5.64
324.74
143.85
0.45
Proposed Center)
209
100-year
848.00
297.00
303.19
303.28
0.001056
2.36
429.09
168.35
0.23
Proposed Center)
174
100-year
848.00
297.00
302.97
303.21
0.002692
4.59
384.23
215.20
0.38
Proposed Center)
145
100-year
848.00
297.00
302.21
302.21
303.05
0.010185
8.40
217.72
146.60
0.69
Proposed Center)
104
100-year
848.00
296.70
301.85
302.28
0.003840
5.38
217.68
136.71
0.45
Proposed Center)
6
100-year
848.00
296.00
301.08
301.07
301.69
0.010013
7.76
270.90
209.15
0.65