SW4210302_2021-02-26 Hydrology Report with Appendices_20210423

HYDROLOGY AND EROSION CONTROL STUDY
FOR
Poplar Grove Child Development Center Expansion
538 Poplar Grove Road
Boone, NC 12345
PIN 2900-58-7299, 2900-58-6723
CDC project No. 21965
•• 1
Appalachian State University
ASU Box 32050
Boone, NC 28608
Contact: David Jones
[phone]
ENGINEER
Michael J. C ' F
Ro
\ _ �oFEssiq%
SEAL
047788
�jC,
March 2, 2021
CDCivil
Design
Concepts, PA
168 Patton Avenue, Asheville, NC 28801
828-252-5388

TABLE OF CONTENTS
ITEWDESCRIPTION
PAGE NO.
1.0 Proj ect Narrative...........................................................................................
1
2.0 Executive Summary.....................................................................................
1
3.0 Erosion Controls...........................................................................................
2
4.0 Stormwater Quantity Analysis.....................................................................
2
4.1 Detention Methodology....................................................................
2
4.2 Allowable Hydrology.......................................................................
2
5.0 Stormwater Quality Analysis.......................................................................
3
APPENDICES
Appendix A
GIS & Aerial Maps
Appendix B
FEMA Map
Appendix C
USDA NRCS Soils Report
Appendix D
Pre- and Post -Development Drainage Area Maps
Appendix E
NOAA Rainfall Depth Data
Appendix F
1-Inch Storm Event HydroCAD Output Report
Appendix G
25-Year Storm Event HydroCAD Output Report

Hydrology and Erosion Control Study
Poplar Grove Daycare Expansion
1.0 INTRODUCTION
Page 1
The project is located at 538 Poplar Grove Rd within the jurisdictional limits of the Town of Boone,
NC. The parcel is 3.90 acres. The project will disturb approximately 1.55 acres. Adjacent to the site is
developed land with residential property to the north, west, and east, and undeveloped land to the south.
The parcel was previously developed and consists of the existing Appalachian State University Child
Development Center with associated asphalt driveway and parking. A GIS map and aerial map are
included in Appendix A.
Stormwater drains to from south to north towards Hodges Creek located on the western side of the
parcel and eventually to a 24-inch RCP culvert at the northwest border of the parcel. This existing
culvert transmits Hodges Creek and discharges approximately 166 linear feet downstream of the parcel.
Currently there are no detention or water quality facilities on site. It is the intent of this report to
demonstrate that the proposed stormwater management facilities will comply with water quantity and
quality controls as regulated by the Town of Boone and the State of North Carolina. At the time of this
report, there were no known drainage concerns related to this site or downstream properties.
The stormwater management facilities for this project will include 130 linear feet of 72-inch RCP, a
control structure, and an NCDEQ approved Bayfilter stormwater filtration system.
Collected stormwater will be routed through a Bayfilter vault system that is designed to treat the first
inch of rainfall. Discharge from the treatment system, as well as any larger flows which may bypass
the treatment system, will enter the 60-inch pipe, and be detained by outlet control structure (Al) fitted
with an orifice and weir. The system is designed to detain the post -developed peak flow rate for the 1
and 25-year storm events to match the pre -developed peak flow rate. The detention system will drain
by 24-inch HDPE outlet pipe to Hodges Creek.
2.0 EXECUTIVE SUMMARY
Based on the analysis that follows, the project will comply with the requirements of the Town of Boone
and the State of North Carolina. Details can be found in the following sections of this report.
Table 2.0: Stormwater Management Summary
Modeled Storm
Event
Pre -Development Flow
(cfs)
Post -Development Flow
(cfs)
Staging Elevation
1-Year
6.46
6.36
3310.89
25-Year
28.65
28.41
3314.44
Modeled flows from the project were less than the pre -development flow rates. The project will treat
the first inch of rainfall for stormwater quality requirements.

Hydrology and Erosion Control Study
Poplar Grove Daycare Expansion
3.0 EROSION CONTROLS
Page 2
The parcel consists of 3.9 acres. Approximately 1.55 acres will be disturbed by construction activities.
The FEMA Map for this parcel is included in Appendix B. A USDA NRCS Soils Report is included in
Appendix C.
Erosion controls will be completed in a three-phase approach. Refer to the construction plans for
further detail on the erosion control measures. Phase 1 will include site clearing, rough grading, and
installation of the proposed stream diversion pipe. During this phase, erosion control devices will
consist of double row perimeter silt fences, and inlet protection for existing inlets on site.
Phase 2 will include site development and utility installation. During this phase inlet protection will be
added as construction progresses as well as the detention basin and stormwater filtration system. Rip
rap aprons will be added to pipe outfalls.
Phase 3 will consist of site stabilization. Following construction, the site will be stabilized with
vegetation, pavement, buildings, etc. A Landscape Compliance Plan is provided as Sheet L101.
4.0 STORMWATER QUANTITY ANALYSIS
The following methodology has been incorporated in the analysis and design of the stormwater
detention features of the site. Stormwater was modeled using HydroCAD, Version 10.00. No portion
of this project is located within a floodplain. All conveyance pipes have been sized to handle the 25-
year storm event.
4.1 Detention Methodology: The majority of stormwater flows from the developed portions of the
site will be collected by a series of curb and gutter, stormwater inlets, and piping and discharged into a
below ground detention basin. The detention system will be designed to comply with NCDEQ and
Town of Boone development guidelines to control post developed peak rates of runoff. The detention
system will combine with bypass drainage areas and discharge to Hodges Creek.
4.2 Allowable Hydrology: Post Developed peak rates of runoff from the subject property must be
kept below or equal to the existing condition flows for the 1 and 25-year 24-hour storm events. All
calculations are based on the existing pre -developed drainage area and soil conditions, as illustrated on
the pre- and post -development drainage area maps (See Appendix D). Please see Appendix E for
rainfall depth used to develop flows for the sub -basins and drainage areas.
The calculated outflow from the Poplar Grove Daycare Expansion combines the detained flows with
the bypass area identified on the drainage area maps. The hydrograph summary as shown below shows
the difference in existing conditions and combined proposed flows.

Hydrology and Erosion Control Study
Poplar Grove Daycare Expansion
Table 4.2A: Stormwater Flowrate Analysis
Page 3
Pre -Developed
Proposed flow
Detained flow
Proposed
Total Post -
Flow
to Stormwater
from Stormwater
Bypass
Developed
Modeled
Basin
Basin
Flow
Flow
Storm
(cfs)
Event
cfs)
(cfs)
(cfs)
(cfs
1-Year
6.46
6.23
4.09
2.27
6.36
25-Year
28.65
17.15
14.33
14.09
28.41
Table 4.2B: Stormwater Staging Analysis
Modeled
Staging
Top of Stormwater
Storm
Elevation
Detention Basin
Freeboard
Event
feet
feet
feet
1-Year
3310.89
3317.2
6.31
25-Year
3314.44
3317.2
2.76
Based on the data presented in Tables 4.2A and B, the project will detain post -developed flow to less
than pre -developed flows for the 1 and 25-year storm events. In addition, the system will bypass the
25-year storm event while maintaining 2.76 feet of freeboard.
A HydroCAD output report for the 1-inch and 25-year rainfall events are presented in Appendices F
and G, respectively. See Site Development Plans for details of the stormwater detention system and
outlet control structure.
5.0 STORMWATER QUALITY ANALYSIS
The NCDEQ requires that the Project treat stormwater from the first 1-inch of rainfall. Water quality
will be treated using a Bayfilter system and will comply with the states guidelines for design of this
system. Details for the design are Sheet C943.

APPENDIX A
GIS Map
Aerial Map

. 'y
V
ARIAL MAP FOR: NOT TO SCALE 168 PATTON AVENUE
ASHEVILLE, NC 28801
POPLAR GROVE PHONE [phone]
FAX [phone]
DAYCARE EXPANSION C �'""
Design 52 WALNUT STREET-SUITE9
Concepts, PA WAYNESVILLE, NC 28786
PHONE [phone]
L. CDC PROJECT #21965 NCEELS LICENSE w: C-2184 WWWAlffid-ign..... pt,— FAX [phone]

Watauaa Countv Tax Information
Parcel ID: 2900-58-7299-000
Tax District: F02
Property Address: 538 POPLAR GROVE RD
Town of Boone Information
Zoning District: Town Limits
Zoning: E4 Educational District
Conditional Use: N/A
Conditional: N/A
Corridor District: N/A
Watershed: N/A
Flood Zone: N/A
View Shed Protection Area: N/A
Municipal Service District: N/A
Central Fire District: Central Fire District
Neighborhood Conservation District: N/A
Disclaimer:
This map is based on the Watauga County Tax Parcel Map.
All layers have been modified to this base.
This is a thematic map for general planning purposes only.
This map is subject to quarterly updates and revisions.
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FEMA FIRM Map

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APPENDIX C
USDA NRCS Soils Report

USDA United States
Department of
Agriculture
MRCS
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
Watauga County,
North Carolina
March 18, 2020

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....................................................................................................................
2
How Soil Surveys Are Made..................................................................................5
SoilMap..................................................................................................................
8
SoilMap................................................................................................................9
Legend................................................................................................................10
MapUnit Legend................................................................................................
11
MapUnit Descriptions.........................................................................................11
Watauga County, North Carolina....................................................................
13
PuE—Porters loam, 30 to 50 percent slopes, stony....................................13
SnC—Saunook loam, central mountains, 8 to 15 percent slopes...............14
SnD—Saunook loam, central mountains, 15 to 30 percent slopes.............15
References............................................................................................................17

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
PuE
Porters loam, 30 to 50 percent
1.2
21.8%
slopes, stony
SnC
Saunook loam, central
3.2
58.4%
mountains, 8 to 15 percent
slopes
SnD
Saunook loam, central
1.1
19.8%
mountains, 15 to 30 percent
slopes
Totals for Area of Interest
5.4
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.
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
11

Custom Soil Resource Report
pure taxonomic classes but rather to separate the landscape into landforms or
landform 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.
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.
12

Custom Soil Resource Report
Watauga County, North Carolina
PuE—Porters loam, 30 to 50 percent slopes, stony
Map Unit Setting
National map unit symbol: Ix6q
Elevation: 2,800 to 4,900 feet
Mean annual precipitation: 45 to 70 inches
Mean annual air temperature: 46 to 57 degrees F
Frost -free period: 100 to 150 days
Farmland classification: Not prime farmland
Map Unit Composition
Porters, stony, and similar soils: 80 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Porters, Stony
Setting
Landform: Ridges, mountain slopes
Landform position (two-dimensional): Backslope
Landform position (three-dimensional): Upper third of mountainflank, side slope
Down -slope shape: Convex
Across -slope shape: Convex
Parent material: Affected by soil creep in the upper solum over residuum
weathered from igneous and metamorphic rock
Typical profile
A - 0 to 10 inches: loam
Bw - 10 to 45 inches: loam
Cr - 45 to 54 inches: weathered bedrock
R - 54 to 80 inches: unweathered bedrock
Properties and qualities
Slope: 30 to 50 percent
Percent of area covered with surface fragments: 0.1 percent
Depth to restrictive feature: 40 to 60 inches to paralithic bedrock; 40 to 60 inches
to lithic bedrock
Natural drainage class: Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat): Very low to low (0.00
to 0.01 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water storage in profile: Moderate (about 7.0 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 6e
Hydrologic Soil Group: A
Hydric soil rating: No
13

Custom Soil Resource Report
SnC—Saunook loam, central mountains, 8 to 15 percent slopes
Map Unit Setting
National map unit symbol: 2xpcp
Elevation: 1,390 to 4,440 feet
Mean annual precipitation: 41 to 63 inches
Mean annual air temperature: 46 to 57 degrees F
Frost -free period: 132 to 180 days
Farmland classification: Farmland of statewide importance
Map Unit Composition
Saunook, central mountains, and similar soils: 80 percent
Minor components: 20 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Saunook, Central Mountains
Setting
Landform: Drainageways, coves, fans
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Mountainbase, base slope
Down -slope shape: Linear, convex
Across -slope shape: Linear, convex
Parent material: Colluvium derived from igneous and metamorphic rock
Typical profile
Ap - 0 to 9 inches: loam
Btl - 9 to 35 inches: loam
Bt2 - 35 to 80 inches: cobbly loam
Properties and qualities
Slope: 8 to 15 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: Medium
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 storage in profile: Moderate (about 8.7 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: B
Hydric soil rating: No
Minor Components
Cullasaja, central mountains
Percent of map unit. 8 percent
14

Custom Soil Resource Report
Landform: Coves, fans, drainageways
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Mountainbase, base slope
Down -slope shape: Convex, linear
Across -slope shape: Convex, linear
Hydric soil rating: No
Cullowhee, central mountains, frequently flooded
Percent of map unit: 7 percent
Landform: Flood plains
Landform position (three-dimensional): Rise
Down -slope shape: Linear
Across -slope shape: Concave
Hydric soil rating: No
Nikwasi, central mountains, frequently flooded
Percent of map unit: 5 percent
Landform: Flood plains, depressions
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Mountainbase, base slope, rise
Down -slope shape: Linear, concave
Across -slope shape: Concave
Hydric soil rating: Yes
SnD—Saunook loam, central mountains, 15 to 30 percent slopes
Map Unit Setting
National map unit symbol: 2xper
Elevation: 1,740 to 4,320 feet
Mean annual precipitation: 42 to 63 inches
Mean annual air temperature: 46 to 57 degrees F
Frost -free period: 132 to 180 days
Farmland classification: Farmland of local importance
Map Unit Composition
Saunook, central mountains, and similar soils: 85 percent
Minor components: 15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Saunook, Central Mountains
Setting
Landform: Drainageways, coves, fans
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Mountainbase, base slope
Down -slope shape: Linear, convex
Across -slope shape: Linear, convex
Parent material: Colluvium derived from igneous and metamorphic rock
Typical profile
Ap - 0 to 9 inches: loam
15

Custom Soil Resource Report
Btl - 9 to 35 inches: loam
Bt2 - 35 to 80 inches: cobbly loam
Properties and qualities
Slope: 15 to 30 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: High
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 storage in profile: Moderate (about 8.7 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 6e
Hydrologic Soil Group: B
Hydric soil rating: No
Minor Components
Cullasaja, central mountains, very stony
Percent of map unit. 8 percent
Landform: Fans, drainageways, coves
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Mountainbase, base slope
Down -slope shape: Linear, convex
Across -slope shape: Convex, linear
Hydric soil rating: No
Cullowhee, central mountains, frequently flooded
Percent of map unit. 7 percent
Landform: Flood plains
Landform position (three-dimensional): Rise
Down -slope shape: Linear
Across -slope shape: Concave
Hydric soil rating: No
it.

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
17

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
18

APPENDIX D
Pre- and Post- Development
Drainage Area Maps

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APPENDIX E
NOAA Rainfall Depth Data

NOAA Atlas 14, Volume 2, Version 3
' Location name: Boone, North Carolina, USA* �,�
Latitude: 36.2168°, Longitude: *81.6917°
Elevation: 3332.31 ft*
*source: ESRI Maps V
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
Duration
Average recurrence interval (years)
1
���
2
5
10
25
50
100
200
500
1000
0.401
0.481
0.559
0.624
0.711
0.781
0.854
0.930
1.04
1.13
5-min
(0.369-0.438)
(0.444-0.525)
(0.514-0.610)
(0.571-0.681)
(0.644-0.781)
(0.698-0.861)
(0.751-0.950)
(0.804-1.05)
(0.872-1.19)
(0.925-1.31)
0.640
0.769
0.895
0.997
1.13
1.24
1.36
1.48
1.64
1.77
10-min
(0.590-0.700)
(0.710-0.840)
(0.824-0.977)
(0.914-1.09)
(1.03-1.24) 1
1 (1.19-1.51)
(1.27-1.66)
(1.38-1.88)
(1.46-2.06)
0.800
0.966
1.13
1.26
1.44
1.57
1.71
1.86
2.06
2.23
15-min
(0.738-0.875)
(0.893-1.06)
1 (1.04-1.24)
1 (1.16-1.38) 11
(1.30-1.58) 1
1 (1.51-1.91)
(1.61-2.10)
(1.74-2.36)
(1.83-2.58)
1.10
1.34
1.61
1.83
2.13
2.37
2.63
2.90
3.28
3.60
30-min
(1.01-1.20) 11
(1.23-1.46)
1 (1.48-1.76)
1 (1.68-2.00) 11
(1.93-2.34)
1 (2.31-2.92)
(2.51-3.26)
(2.76-3.76)
(2.96-4.18)
1.37
1.68
2.06
2.38
2.83
3.21
3.62
4.06
4.71
5.26
60-min
(1.26-1.50) 11
(1.55-1.83)
1 (1.90-2.25)
1 (2.18-2.60) 11
(2.57-3.11) 11
(2.87-3.55)
1 (3.18-4.03)
(3.51-4.57)
(3.96-5.39)
(4.32-6.10)
1.65
2.03
2.53
2.94
3.55
4.06
4.64
5.28
6.26
7.14
2-hr
(1.51-1.79)
(1.86-2.21)
(2.32-2.75)
(2.67-3.19)
(3.19-3.87)
(3.61-4.46)
(4.05-5.14)
(4.53-5.92)
(5.22-7.14)
(5.82-8.26)
1.80
2.21
2.75
3.20
3.87
4.46
5.10
5.84
6.96
7.97
3-hr
(1.66-1.97)
(2.04-2.42)
(2.52-3.01)
(2.92-3.50)
(3.48-4.26)
(3.96-4.94)
(4.45-5.71)
(5.00-6.61)
(5.78-8.02)
(6.46-9.33)
2.38
2.92
3.59
4.14
4.97
5.67
6.45
7.32
8.64
9.85
6-hr
(2.21-2.59) 11
(2.70-3.18)
1 (3.31-3.91)
1 (3.80-4.52) 11
(4.50-5.46) 11
(5.08-6.27)
1 (5.69-7.21)
(6.35-8.29)
(7.28-9.97)
(8.11-11.5)
3.16
3.85
4.70
5.36
6.28
7.03
7.84
8.72
10.0
11.2
12-hr
(2.92-3.41)
(3.56-4.18)
(4.33-5.11)
(4.92-5.84)
(5.72-6.88)
(6.33-7.76)
(6.97-8.73)
(7.64-9.81)
(8.60-11.5)
(9.45-13.0)
3.75
4.54
5.79
6.82
8.32
9.59
11.0
12.5
14.7
16.7
24-hr
(3.45-4.09)
(4.19-4.97)
(5.33-6.35)
(6.24-7.48)
(7.55-9.14)
(8.61-10.6)
(9.73-12.2)
(10.9-14.0)
(12.6-16.7)
(14.0-19.1)
4.51
7 6-A6
6.91
8.14
7 9.94
11.5
13.2
15.0
77.8
20.2
2-day
(4.16-4.91)
(5.03-5.94)
(6.37-7.55)
(7.46-8.89)
(9.03-10.9)
1 (11.7-14.6)
(13.1-16.8)
(15.2-20.2)
(16.8-23.2)
4.83
5.83
7.33
8.58
10.4
11.9
13.6
15.4
18.1
20.4
3-day
(4.47-5.24)
(5.40-6.32)
(6.77-7.97)
(7.89-9.33)
(9.47-11.3) 11
(10.7-13.1)
1 (12.1-15.0)
(13.5-17.1)
(15.5-20.4)
(17.2-23.3)
5.15
6.21
7.75
9.01
10.8
12.3
14.0
15.7
18.3
20.6
4-day
(4.78-5.57)
(5.77-6.71)
(7.17-8.39)
(8.31-9.77)
(9.91-11.8) 11
(11.2-13.5)
1 (12.5-15.4)
(13.9-17.4)
(15.9-20.6)
(1 7.5-23.5)
5.87
7.03
8.66
9.98
11.9
13.4
15.0
16.8
19.3
21.4
7-day
(5.49-6.31)
(6.58-7.55)
(8.07-9.31)
(9.27-10.7)
(10.9-12.8) 11
(12.2-14.6)
1 (13.6-16.5)
(15.0-18.5)
(16.9-21.6)
(18.4-24.2)
6.68
7.97
9.63
10.9
12.8
14.2
15.7
17.3
19.5
21.5
10tlay
(6.27-7.13)
(7.47-8.49)
(9.01-10.3)
(10.2-11.7) 11
(11.8-13.6) 1
1 (14.3-17.0)
(15.6-18.8)
(17.3-21.8)
(18.8-24.5)
8.90
10.5
12.5
14.1
16.3
18.0
19.8
21.7
24.3
26.4
20tlay
(8.41-9.43)
(9.96-11.1)
(11.8-13.2)
(13.3-15.0)
(15.2-17.3) 11
(16.8-19.3)
1 (18.3-21.4)
(19.8-23.5)
(21.8-26.6)
(23.4-29.2)
10.9
12.9
15.2
16.9
19.3
21.2
23.1
25.0
27.5
29.5
30tlay
(10.3-11.6)
(12.2-13.7)
(14.3-16.1)
(15.9-18.0)
(18.1-20.6)
(19.7-22.6)
(21.3-24.7)
(22.8-27.0)
(24.9-30.0)
(26.4-32.5)
13.8
16.1
18.6
20.6
23.2
25.2
27.3
29.3
32.0
34.1
45tlay
(13.0-14.5)
(15.3-17.0)
(17.6-19.7)
(19.4-21.8)
(21.8-24.6)
(23.6-26.9)
(25.3-29.2)
(27.0-31.6)
(29.1-34.8)
(30.7-37.4)
16.4
19.1
21.9
24.0
26.8
29.0
31.0
33.0
35.6
37.6
60tlay
(15.6-17.2)
(18.2-20.2)
(20.8-23.1)
(22.8-25.3)
(25.4-28.4)
(27.3-30.7)
(29.0-33.0)
(30.7-35.3)
(32.9-38.5)
(34.5-40.9)
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

PDS-based depth -duration -frequency (DDF) curves
Latitude: 36.2168'. Longitude:-81.6917'
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35
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Duration
40
35
c
30
v. 25
CU
0 20
49
'a 15
� 10
.............
0
1 2 5 10 25 50 100 200 500 1000
Average recurrence interval (years)
NOAA Atlas 14, Volume 2. Version 3 Created (GMT): Man Sep 28 17:34:02 2020
Back to Top
Maps & aerials
Small scale terrain
Average recurrence
inl erva I
{�reara}
—t
2
5
10
— 25
50
100
200
600
1000
Duration
— "in —
2-day
— 10-min —
3-d3y
15-min —
4--d ay
— 3D-min —
TAay
— 60-inin —
1 D-eay
— 2-rr —
20-day
— 3-nr —
30-day
— "r —
45-day
— 12-nr —
60-day
24-ri r

X,
Lar e scale terrain
IRN W-� FIFF7,k
T IM
. . . . . . . . . . . ....... i . . . . . . ........... . . . . . ..... ..... ..........
Kingspoit' Bristol
johnson cit}l1Winston-Salem
lie
I.At r-lildhell Greensboro
AsheAll-e N 0 R T H C A I T
Charlotte
Fa
Large scale map
King port
. Johnson ���inston le
Giree
noxville
Asheville
; 1P k N. J, a
arlotte
100km
Mi
Large scale aerial

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?: [e-mail]
Disclaimer

NOAA Atlas 14, Volume 2, Version 3
' Location name: Boone, North Carolina, USA* �,�
Latitude: 36.2168°, Longitude: *81.6917°
Elevation: 3332.31 ft*
*source: ESRI Maps V
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/hour)1
Average
recurrence interval (years)
1
2
5
10
25
50
100
200
500
1000
4.81
5.77
6.71
7.49
8.53
9.37
10.2
11.2
12.4
13.5
5-min
(4.43-5.26) 11
(5.33-6.30)
1 (6.17-7.32)
1 (6.85-8.17) 11
(7.73-9.37) 11
(8.38-10.3)
1 (9.01-11.4)
1 (9.65-12.6) 11
(10.5-14.2)
1 (11.1-15.7)
3.84
4.61
5.37
5.98
6.80
7.46
8.14
8.85
9.83
10.6
10-min
(3.54-4.20)
(4.26-5.04)
(4.94-5.86)
1 (5.48-6.53) 11
(6.16-7.46) 11
(6.67-8.23)
1 (7.16-9.05)
1 (7.65-9.96) 11
(8.27-11.3)
1 (8.74-12.3)
3.20
3.86
4.53
5.04
5.75
6.30
6.86
7.44
8.25
8.90
15-min
(2.95-3.50)
(3.57-4.22)
(4.17-4.94)
1 (4.62-5.51) 11
(5.20-6.31) 11
(5.63-6.95)
1 (6.04-7.63)
1 (6.44-8.38) 11
(6.94-9.44)
1 (7.32-10.3)
2.19
2.67
3.22
3.66
4.26
4.74
5.25
5.79
6.56
7.21
30-min
(2.02-2.40) 11
(2.47-2.92)
1 (2.96-3.51)
1 (3.35-3.99) 11
(3.86-4.67) 11
(4.24-5.23)
1 (4.62-5.84)
1 (5.01-6.52) 11
(5.52-7.51)
1.37
1.68
2.06
2.38
2.83
3.21
3.62
4.06
4.71
5.26
60-min
(1.26-1.50) 11
(1.55-1.83)
1 (1.90-2.25)
1 (2.18-2.60) 11
(2.57-3.11) 11
(2.87-3.55)
1 (3.18-4.03)
1 (3.51-4.57) 11
(3.96-5.39)
1 (4.32-6.10)
0.824
1.01
1.26
1.47
1.77
2.03
2.32
2.64
3.13
3.57
2-hr
(0.756-0.894)
(0.932-1.10)
1 (1.16-1.37)
1 (1.34-1.60) 11
(1.60-1.93) 11
(1.80-2.23)
1 (2.03-2.57)
1 (2.27-2.96) 11
(2.61-3.57)
0.599
0.737
0.916
1.07
1.29
1.48
1.70
1.94
2.32
2.65
3-hr
(0.553-0.655)
(0.679-0.807)
(0.840-1.00)
(0.972-1.1 7) 11
(1.16-1.42) 11
(1.32-1.65)
1 (1.48-1.90)
1 (1.66-2.20) 11
(1.92-2.67)
1 (2.15-3.11)
0.398
0.487
0.599
0.692
0.829
0.947
1.08
1.22
1.44
1.65
6-hr
(0.369-0.432)
(0.451-0.531)
(0.552-0.653)
(0.634-0.756)
(0.752-0.911)
(0.848-1.05)
(0.950-1.20)
1 (1.06-1.38) 11
(1.22-1.67)
1 (1.36-1.93)
0.262
0.320
0.390
0.445
0.521
0.584
0.650
0.724
0.832
0.932
12-hr
(0.242-0.283)
(0.296-0.347)
(0.360-0.424)
(0.408-0.485)
(0.474-0.571)
(0.526-0.644)
(0.579-0.724)
(0.634-0.814)
(0.713-0.952)
(0.784-1.08)
0.156
0.189
0.241
0.284
0.347
0.400
0.457
0.521
0.615
0.695
24-hr
(0.144-0.171)
(0.174-0.207)
(0.222-0.265)
(0.260-0.312)
(0.314-0.381)
(0.359-0.441)
(0.406-0.509)
(0.455-0.583)
(0.525-0.697)
(0.584-0.797)
0.094
0.113
0.144
0.170
0.207
0.239
0.274
0.313
0.371
0.422
2{iay
(0.087-0.102)
(0.105-0.124)
(0.133-0.157)
(0.155-0.185)
(0.188-0.227)
(0.215-0.263)
(0.243-0.304)
(0.273-0.350)
(0.316-0.421)
(0.351-0.484)
0.067
0.081
0.102
0.119
0.144
0.165
0.188
0.214
0.251
0.284
3{iay
(0.062-0.073)
(0.075-0.088)
(0.094-0.111)
(0.110-0.130)
(0.132-0.157)
(0.149-0.181)
(0.168-0.208)
(0.187-0.238)
(0.215-0.283)
(0.239-0.324)
0.054
0.065
0.081
0.094
0.113
0.129
0.145
0.164
0.191
0.215
4{iay
(0.050-0.058)
(0.060-0.070)
(0.075-0.087)
(0.087-0.102)
(0.103-0.123)
(0.116-0.140)
(0.130-0.160)
(0.145-0.182)
(0.165-0.214)
(0.183-0.244)
0.035
0.042
0.052
0.059
0.071
0.080
0.090
0.100
0.115
0.127
7 tl ay
(0.033-0.038)
(0.039-0.045)
(0.048-0.055)
(0.055-0.064)
(0.065-0.076)
(0.073-0.087)
(0.081-0.098)
(0.089-0.110) 11
(0.101-0.129)
1 (0.110-0.144)
0.028
0.033
0.040
0.046
0.053
0.059
0.065
0.072
0.081
0.089
10tlay
(0.026-0.030)
(0.031-0.035)
(0.038-0.043)
(0.043-0.049)
(0.049-0.057)
(0.055-0.064)
(0.060-0.071)
(0.065-0.078)
(0.072-0.091)
(0.078-0.102)
0.019
0.022
0.026
0.029
0.034
0.038
0.041
0.045
0.051
0.055
20tlay
(0.018-0.020)
(0.021-0.023)
(0.025-0.028)
(0.028-0.031)
(0.032-0.036)
(0.035-0.040)
(0.038-0.045)
(0.041-0.049)
(0.045-0.055)
(0.049-0.061)
0.015
0.018
0.021
0.024
0.027
0.029
0.032
0.035
0.038
0.041
30tlay
(0.014-0.016)
(0.017-0.019)
(0.020-0.022)
(0.022-0.025)
(0.025-0.029)
(0.027-0.031)
(0.030-0.034)
(0.032-0.037)
(0.035-0.042)
(0.037-0.045)
0.013
0.015
0.017
0.019
0.021
0.023
0.025
0.027
0.030
0.032
45tlay
(0.012-0.013)
(0.014-0.016)
(0.016-0.018)
(0.018-0.020)
(0.020-0.023)
(0.022-0.025)
(0.023-0.027)
(0.025-0.029)
(0.027-0.032)
(0.028-0.035)
0.011
0.013
0.015
0.017
0.019
0.020
0.022
0.023
0.025
0.026
60tlay
(0.011-0.012)
(0.013-0.014)
(0.014-0.016)
(0.016-0.018)
(0.018-0.020)
(0.019-0.021)
(0.020-0.023)
(0.021-0.025)
(0.023-0.027)
(0.024-0.028)
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

101SX061
10-00
ZI
3 Wflf
001
PDS-based intensity -duration -frequency (IMF) curves
Latitude: 36.2168 Lcngitude:-81.6917'
T I I I I I I I I I I
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C
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S
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},
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Duration
100.00
10-00
ZI
a
3 Reif
0.01 — I 1 1 1 1 I 1 1
1 2 5 10 25 50 100 200 500 1000
Average recurrence interval (years)
NOAA Atlas 14, Volume 2, Version 3 Created (GMT): Mon Sep 28 17:34:40 2020
Back to Top
Maps & aerials
Small scale terrain
Average recurrence
inl erva I
{�reara}
— f
2
5
10
25
50
100
200
Soo
1000
Duration
— "in —
2-day
— 10-min —
3-d3y
164nin —
4--d ay
— 3D-min —
TAay
— 60-inin —
1 D-eay
— 2-rr —
20-day
— 3-nr —
30-day
— "r —
45-day
— 12-nr —
60-day
24-ri r

X,
Lar e scale terrain
IRN W-� FIFF7,k
T IM
. . . . . . . . . . . ....... i . . . . . . ........... . . . . . ..... ..... ..........
Kingspoit' Bristol
johnson cit}l1Winston-Salem
lie
I.At r-lildhell Greensboro
AsheAll-e N 0 R T H C A I T
Charlotte
Fa
Large scale map
King port
. Johnson ���inston le
Giree
noxville
Asheville
; 1P k N. J, a
arlotte
100km
Mi
Large scale aerial

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?: [e-mail]
Disclaimer

APPENDIX F
1-Year Storm Event HydroCAD Report

is (2s 5S
Pre Post Bypass
47 1�7
3P a4L
Detention Bypass Link
S4
Reach on L
ink

2021-03-02 ASU Poplar Grove MJC Type 11 24-hr 1 year Rainfall=3.75"
Prepared by {enter your company name here} Printed 3/2/2021
HvdroCAD® 10.00-12 s/n 04679 © 2014 HvdroCAD Software Solutions LLC Paae 2
Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: Pre Runoff Area=169,884 sf 17.70% Impervious Runoff Depth>0.94"
Flow Length=431' Tc=8.0 min CN=68 Runoff=6.46 cfs 13,298 cf
Subcatchment 2S: Post Runoff Area=68,389 sf 63.74% Impervious Runoff Depth>2.08"
Tc=5.0 min CN=85 Runoff=6.23 cfs 11,827 cf
Subcatchment 5S: Bypass Runoff Area=101,495 sf 0.00% Impervious Runoff Depth>0.60"
Flow Length=431' Tc=8.0 min CN=61 Runoff=2.27 cfs 5,094 cf
Pond 3P: Detention Peak Elev=3,310.89' Storage=1,672 cf Inflow=6.23 cfs 11,827 cf
Outflow=4.09 cfs 11,798 cf
Link 4L: Bypass Link Inflow=6.36 cfs 16,893 cf
Primary=6.36 cfs 16,893 cf
Total Runoff Area = 339,768 sf Runoff Volume = 30,219 cf Average Runoff Depth = 1.07"
78.32% Pervious = 266,115 sf 21.68% Impervious = 73,653 sf

2021-03-02 ASU Poplar Grove MJC Type 11 24-hr 1 year Rainfall=3.75"
Prepared by {enter your company name here} Printed 3/2/2021
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 3
Summary for Subcatchment 1S: Pre
Runoff = 6.46 cfs @ 12.00 hrs, Volume= 13,298 cf, Depth> 0.94"
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 1 year Rainfall=3.75"
Area (sf) CN Description
139,822
61 >75% Grass cover, Good, HSG B
30,062
98 Paved parking, HSG B
169,884
68 Weighted Average
139,822
82.30% Pervious Area
30,062
17.70% Impervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
5.4
100
0.4000
0.31
Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 4.54"
2.5
169
0.2000
1.12
Shallow Concentrated Flow,
Forest w/Heavy Litter Kv= 2.5 fps
0.1
162
0.0600
23.11
163.38 Pipe Channel,
36.0" Round Area= 7.1 sf Perim= 9.4' r= 0.75'
n= 0.013 Corrugated PE, smooth interior
8.0 431 Total
N
U
3
0
LL
■ Runoff

2021-03-02 ASU Poplar Grove MJC Type 11 24-hr 1 year Rainfall=3.75"
Prepared by {enter your company name here} Printed 3/2/2021
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 4
Summary for Subcatchment 2S: Post
[49] Hint: Tc<2dt may require smaller dt
Runoff = 6.23 cfs @ 11.96 hrs, Volume= 11,827 cf, Depth> 2.08"
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 1 year Rainfall=3.75"
Area (sf) CN Description
43,591 98 Paved parking, HSG B
24,798 61 >75% Grass cover, Good, HSG B
68,389 85 Weighted Average
24,798 36.26% Pervious Area
43,591 63.74% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
■ Runoff
N
U
3
0
LL

2021-03-02 ASU Poplar Grove MJC Type 11 24-hr 1 year Rainfall=3.75"
Prepared by {enter your company name here} Printed 3/2/2021
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 5
Summary for Subcatchment 5S: Bypass
Runoff = 2.27 cfs @ 12.01 hrs, Volume= 5,094 cf, Depth> 0.60"
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 1 year Rainfall=3.75"
Area (sf) CN Description
101,495 61 >75% Grass cover, Good, HSG B
101,495 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
5.4
100
0.4000
0.31
Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 4.54"
2.5
169
0.2000
1.12
Shallow Concentrated Flow,
Forest w/Heavy Litter Kv= 2.5 fps
0.1
162
0.0600
23.11
163.38 Pipe Channel,
36.0" Round Area= 7.1 sf Perim= 9.4' r= 0.75'
n= 0.013 Corruaated PE. smooth interior
8.0 431 Total
❑ Runoff

2021-03-02 ASU Poplar Grove MJC Type 11 24-hr 1 year Rainfall=3.75"
Prepared by {enter your company name here} Printed 3/2/2021
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 6
Summary for Pond 3P: Detention
Inflow Area = 68,389 sf, 63.74% Impervious, Inflow Depth > 2.08" for 1 year event
Inflow = 6.23 cfs @ 11.96 hrs, Volume= 11,827 cf
Outflow = 4.09 cfs @ 12.03 hrs, Volume= 11,798 cf, Atten= 34%, Lag= 4.3 min
Primary = 4.09 cfs @ 12.03 hrs, Volume= 11,798 cf
Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs / 2
Peak Elev= 3,310.89' @ 12.03 hrs Surf.Area= 995 sf Storage= 1,672 cf
Plug -Flow detention time= 5.7 min calculated for 11,798 cf (100% of inflow)
Center -of -Mass det. time= 4.7 min ( 780.9 - 776.2 )
Volume
Invert
Avail.Storage Storage Description
#1
3,308.60'
3,676 cf 72.0" Round Pipe Storage
L= 130.0'
#2
3,308.60'
594 cf 6.00'W x 9.00'L x 11.00'H BayFilter Vault A3
#3
3,308.60'
1,005 cf 8.00'D x 20.00'H Structure A2
#4
3,310.40'
269 cf 6.00'D x 9.50'H Structure A4
#5
3,308.60'
402 cf 8.00'D x 8.00'H Structure Al
#6
3,310.70'
128 cf 4.00'W x 4.00'L x 8.00'H Structure A5
#7
3,310.40'
57 cf 18.0" Round Pipe A4-A5
L= 32.0' S= 0.0110 7'
#8
3,311.30'
55 cf 18.0" Round Pipe A5-A6
L= 31.0' S= 0.1000 7'
6,185 cf Total Available Storage
Device
Routing
Invert Outlet Devices
#1
Primary
3,308.60' 24.0" Round Culvert
L= 32.0' CPP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 3,308.60' / 3,308.28' S= 0.0100 '/' Cc= 0.900
n= 0.011 Concrete pipe, straight & clean, Flow Area= 3.14 sf
#2
Device 1
3,308.60' 10.7" Vert. Orifice/Grate C= 0.600
#3
Device 1
3,308.60' Custom Weir/Orifice, Cv= 2.62 (C= 3.28)
Head (feet) 0.00 2.25 2.25 6.00 6.00 7.00
Width (feet) 0.00 0.00 0.33 0.33 6.00 6.00
Primary OutFlow Max=4.04 cfs @ 12.03 hrs HW=3,310.85' (Free Discharge)
L1=Culvert (Passes 4.04 cfs of 16.27 cfs potential flow)
�2=Orifi ce/G rate
(Orifice Controls 4.04 cfs @ 6.47 fps)
3=Custom Weir/Orifice (Weir Controls 0.00 cfs @ 0.15 fps)

2021-03-02 ASU Poplar Grove MJC
Type 11 24-hr 1 year Rainfall=3.75"
Prepared by {enter your company name here} Printed 3/2/2021
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 7
N
U
Time (hours)
❑ Inflow
❑ Primary

2021-03-02 ASU Poplar Grove MJC Type 11 24-hr 1 year Rainfall=3.75"
Prepared by {enter your company name here} Printed 3/2/2021
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 8
Summary for Link 4L: Bypass Link
Inflow Area = 169,884 sf, 25.66% Impervious, Inflow Depth > 1.19" for 1 year event
Inflow = 6.36 cfs @ 12.02 hrs, Volume= 16,893 cf
Primary = 6.36 cfs @ 12.02 hrs, Volume= 16,893 cf, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
I nflow
❑ Primary
N
U
3
0
LL

APPENDIX G
25-Year Storm Event HydroCAD Report

is (2s 5S
Pre Post Bypass
47 1�7
3P a4L
Detention Bypass Link
S4
Reach on L
ink

2021-03-02 ASU Poplar Grove MJC Type/1 24-hr 25 year Rainfall=8.32"
Prepared by {enter your company name here} Printed 3/2/2021
HvdroCAD® 10.00-12 s/n 04679 © 2014 HvdroCAD Software Solutions LLC Paae 2
Time span=5.00-20.00 hrs, dt=0.05 hrs, 301 points
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Subcatchment 1S: Pre Runoff Area=169,884 sf 17.70% Impervious Runoff Depth>4.16"
Flow Length=431' Tc=8.0 min CN=68 Runoff=28.65 cfs 58,888 cf
Subcatchment 2S: Post Runoff Area=68,389 sf 63.74% Impervious Runoff Depth>6.12"
Tc=5.0 min CN=85 Runoff=17.15 cfs 34,868 cf
Subcatchment 5S: Bypass Runoff Area=101,495 sf 0.00% Impervious Runoff Depth>3.38"
Flow Length=431' Tc=8.0 min CN=61 Runoff=14.09 cfs 28,555 cf
Pond 3P: Detention Peak Elev=3,314.44' Storage=4,824 cf Inflow=17.15 cfs 34,868 cf
Outflow=14.33 cfs 34,791 cf
Link 4L: Bypass Link Inflow=28.41 cfs 63,345 cf
Primary=28.41 cfs 63,345 cf
Total Runoff Area = 339,768 sf Runoff Volume = 122,311 cf Average Runoff Depth = 4.32"
78.32% Pervious = 266,115 sf 21.68% Impervious = 73,653 sf

2021-03-02 ASU Poplar Grove MJC Type/1 24-hr 25 year Rainfall=8.32"
Prepared by {enter your company name here} Printed 3/2/2021
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 3
Summary for Subcatchment 1S: Pre
Runoff = 28.65 cfs @ 11.99 hrs, Volume= 58,888 cf, Depth> 4.16"
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 25 year Rainfall=8.32"
Area (sf) CN Description
139,822
61 >75% Grass cover, Good, HSG B
30,062
98 Paved parking, HSG B
169,884
68 Weighted Average
139,822
82.30% Pervious Area
30,062
17.70% Impervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
5.4
100
0.4000
0.31
Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 4.54"
2.5
169
0.2000
1.12
Shallow Concentrated Flow,
Forest w/Heavy Litter Kv= 2.5 fps
0.1
162
0.0600
23.11
163.38 Pipe Channel,
36.0" Round Area= 7.1 sf Perim= 9.4' r= 0.75'
n= 0.013 Corrugated PE, smooth interior
8.0 431 Total
N
U
3
0
LL
■ Runoff

2021-03-02 ASU Poplar Grove MJC Type/1 24-hr 25 year Rainfall=8.32"
Prepared by {enter your company name here} Printed 3/2/2021
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 4
Summary for Subcatchment 2S: Post
[49] Hint: Tc<2dt may require smaller dt
Runoff = 17.15 cfs @ 11.95 hrs, Volume= 34,868 cf, Depth> 6.12"
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 25 year Rainfall=8.32"
Area (sf) CN Description
43,591 98 Paved parking, HSG B
24,798 61 >75% Grass cover, Good, HSG B
68,389 85 Weighted Average
24,798 36.26% Pervious Area
43,591 63.74% Impervious Area
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 2S: Post
Hydrograph
1
1
1
1
1
1
1
1
H 1
3
0
LL
■ Runoff

2021-03-02 ASU Poplar Grove MJC Type/1 24-hr 25 year Rainfall=8.32"
Prepared by {enter your company name here} Printed 3/2/2021
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 5
Summary for Subcatchment 5S: Bypass
Runoff = 14.09 cfs @ 12.00 hrs, Volume= 28,555 cf, Depth> 3.38"
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 25 year Rainfall=8.32"
Area (so CN Description
101,495 61 >75% Grass cover, Good, HSG B
101,495 100.00% Pervious Area
Tc
Length
Slope
Velocity
Capacity Description
(min)
(feet)
(ft/ft)
(ft/sec)
(cfs)
5.4
100
0.4000
0.31
Sheet Flow,
Woods: Light underbrush n= 0.400 P2= 4.54"
2.5
169
0.2000
1.12
Shallow Concentrated Flow,
Forest w/Heavy Litter Kv= 2.5 fps
0.1
162
0.0600
23.11
163.38 Pipe Channel,
36.0" Round Area= 7.1 sf Perim= 9.4' r= 0.75'
n= 0.013 Corruaated PE. smooth interior
8.0 431 Total
■ Runoff

2021-03-02 ASU Poplar Grove MJC Type/1 24-hr 25 year Rainfall=8.32"
Prepared by {enter your company name here} Printed 3/2/2021
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 6
Summary for Pond 3P: Detention
[82] Warning: Early inflow requires earlier time span
Inflow Area = 68,389 sf, 63.74% Impervious, Inflow Depth > 6.12" for 25 year event
Inflow = 17.15 cfs @ 11.95 hrs, Volume= 34,868 cf
Outflow = 14.33 cfs @ 12.00 hrs, Volume= 34,791 cf, Atten= 16%, Lag= 2.9 min
Primary = 14.33 cfs @ 12.00 hrs, Volume= 34,791 cf
Routing by Stor-Ind method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs / 2
Peak Elev= 3,314.44' @ 12.00 hrs Surf.Area= 468 sf Storage= 4,824 cf
Plug -Flow detention time= 5.9 min calculated for 34,789 cf (100% of inflow)
Center -of -Mass det. time= 4.8 min ( 756.7 - 751.9 )
Volume
Invert
Avail.Storage Storage Description
#1
3,308.60'
3,676 cf 72.0" Round Pipe Storage
L= 130.0'
#2
3,308.60'
594 cf 6.00'W x 9.00'L x 11.00'H BayFilter Vault A3
#3
3,308.60'
1,005 cf 8.00'D x 20.00'H Structure A2
#4
3,310.40'
269 cf 6.00'D x 9.50'H Structure A4
#5
3,308.60'
402 cf 8.00'D x 8.00'H Structure Al
#6
3,310.70'
128 cf 4.00'W x 4.00'L x 8.00'H Structure A5
#7
3,310.40'
57 cf 18.0" Round Pipe A4-A5
L= 32.0' S= 0.0110 7'
#8
3,311.30'
55 cf 18.0" Round Pipe A5-A6
L= 31.0' S= 0.1000 7'
6,185 cf Total Available Storage
Device
Routing
Invert Outlet Devices
#1
Primary
3,308.60' 24.0" Round Culvert
L= 32.0' CPP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 3,308.60' / 3,308.28' S= 0.0100 '/' Cc= 0.900
n= 0.011 Concrete pipe, straight & clean, Flow Area= 3.14 sf
#2
Device 1
3,308.60' 10.7" Vert. Orifice/Grate C= 0.600
#3
Device 1
3,308.60' Custom Weir/Orifice, Cv= 2.62 (C= 3.28)
Head (feet) 0.00 2.25 2.25 6.00 6.00 7.00
Width (feet) 0.00 0.00 0.33 0.33 6.00 6.00
Primary OutFlow Max=14.29 cfs @ 12.00 hrs HW=3,314.43' (Free Discharge)
L1=Culvert (Passes 14.29 cfs of 33.24 cfs potential flow)
�2=Orifi ce/G rate
(Orifice Controls 6.98 cfs @ 11.17 fps)
3=Custom Weir/Orifice (Weir Controls 7.32 cfs @ 6.20 fps)

2021-03-02 ASU Poplar Grove MJC Type/1 24-hr 25 year Rainfall=8.32"
Prepared by {enter your company name here} Printed 3/2/2021
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 7
Pond 3P: Detention
Hydrograph
❑ Inflow
❑ Primary
Time (hours)

2021-03-02 ASU Poplar Grove MJC Type/1 24-hr 25 year Rainfall=8.32"
Prepared by {enter your company name here} Printed 3/2/2021
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 8
Summary for Link 4L: Bypass Link
Inflow Area = 169,884 sf, 25.66% Impervious, Inflow Depth > 4.47" for 25 year event
Inflow = 28.41 cfs @ 12.00 hrs, Volume= 63,345 cf
Primary = 28.41 cfs @ 12.00 hrs, Volume= 63,345 cf, Atten= 0%, Lag= 0.0 min
Primary outflow = Inflow, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
I nflow
❑ Primary
N
U
3
0
LL