SW1230801_Stormwater Report_20230920

Stormwater & Erosion Control
Engineer's Report
Project Name
Ferncliff Retail (New Substation)
Location
Town of Mills River, Henderson County, NC
DUKE
ENERGY®
Owner
Duke Energy Corp
PO Box 1007
Charlotte, NC 28201
Engineering Firm
DUKE ENERGY CAROLINAS, LLC
6325 Wilkinson Boulevard
Charlotte, NC 28214
N.C. License No. F-0566
Engineer's Contact Information
Contact: Joshua A. Peeler, PE
NC No: 047381
[e-mail]
[phone]
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Date: October 16, 2020
Revised: November 23, 2020 T o``
As-built: February 16, 2023 A
047381 =
DEC Project No: W170199 ✓ r%,`'o'•!►!GINE
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Bookmark Summary
Project Narrative
Engineer As-built - Supporting Documentation
NRCS Soils Report
NOAA Rainfall Data (Intensity in/hr)
NOAA Rainfall Data (Precipitation inches)
Storm Drainage - Conveyance (As-builts)
Storm Drainage System As-built Calculations
FES Calculation Check
Swale D-1 - As-built Calculations
Swale D-2 - As-built Calculations
Swale D-3 - As-built Calculations
CN Tables
Impervious As-built Calculation
Hydraflow Watershed Routing Model
2-Year/24-Hour Storm
10-Year/24-Hour Storm
25-Year/24-Hour Storm
100-Year/24-Hour Storm
2/21/2023

Project Narrative
The project site is located at the corner of Old Fanning Bridge Road and Broadpointe Drive in
the Town of Mills River, North Carolina. The Town of Mills River is located within Henderson
County. The proposed project consists of constructing a new electrical substation to serve the
current and future customers within the Mills River area. The substation will be constructed on a
previously graded pad completed by the previous owner.developer of the property. Duke Energy
has purchased parcel 9642187974, as listed by Henderson County GIS to construct the new
substation. The total parcel is approximately 34-acres with road frontage along Old Fanning
Bridge Road and Broadpoint Drive. The substation driveway access will be provided from
Brodpoint Drive, which is an NCDOT maintained road. Due to the size of the parcel and area
required for the substation, a 9.94-acre tract will be subdivided from the total 34-acre parcel for
the substation. All stormwater impervious calculations and assessments will be based on the
subdivided parcel acreage. The project development will require site plan permitting by the
Town of Mills River, stormwater and erosion control permitting by NCDENR, and
encroachament/access permitting thru NCDOT.
The site drains to the French Broad River to the North and a small portion drainsa to McDowell
Creek to the Southeast. The French Broad River is indexed by NCDENR as 6-(54.75) and
classified as B class stream which is part of the French Broad river basin. McDowell Creek is
indexed as 6-58 and classified as a C class stream . Class C streams are protected for
recreational use for secondary activities as defined by the state. Class B encompass Class C
restrictions and uses and includes primary recreational activites as defined by the state. The site
is not located within a supply watershed according to WSWS GIS mapping provided by
NCDENR. The site is located within a Phase II Post-construction area permitted through the
State of North Carolina and due to the proximity to the Asheville Regional Airport, shall meet all
requirements of MDC Chapter E-4 for Airports.
Pre-developed Condition
The property is currently vacant and has been previously mass graded by the previous owner
and brought to a flat pad with multiple stockpiles and sediment basins across the site. The
current ground cover is grass. The low land between the French Broad River and pad is
planted for agricultural studies by NCSTATE. There is wooded vegetation and heavy
underbrush along the river banks, which make up a protected riparian buffer. According to
FEMA Firm map 3700964200K, panel 9642 the project parcel is located within the Special
Flood Hazard Zone AE, Floodway Areas, and other flood areas of the French Broad River. The
base flood elevation according to the effective map is 2060.00-ft above sea level. The existing
pad is graded to 2070.00-ft above sea level according to a survey completed by Maser
Consulting, P.A. on September 17, 2019, thus any structure constructed on the current pad is
above the FPE of 2061.00-ft mark.
Post-developed Conditions
The proposed project consist of mass grading the site to increase the substation pad elevation.
The existing stockpiles onsite will be used to generate the fill dirt necessary for raising the pad
elevation. The existing skimmer basins will be utilized during construction and will be
refurbished as needed. An ABC crusher run access drive from Broadpointe Drive will be
installed to access the #57 gravel substation pad. The substation pad--and access drive will be
counted as impervious land cover. Laydown areas and additional gravel were installed across

the site during construction and are considered pervious surface according to A-4 of the latest
Stormwater MDC. The Built-Upon Area (BUA) is calculated based on the subdivided 9.94 acre
parcel and is approximately 23%4.87% impervious. The remainder of the site will consist of
grass land cover to be moderately maintained and developed by others. All stormwater and
post-construction SCM's on the remaining acreage, if required per future development plans,
will be permitted, designed and constructed by others. As part of this project a new transmission
line will feed from the existing transmission line cooridor that runs parallel to the French Broad
River. The new transmission line extension will consist of new foundations for poles and
structures . The new transmission line right-of-way and a portion of the existing right-of-way
where work will be performed will be included as part of the denuded limits for the erosion
control permit. Access to lower areas of the site and to existing transmission line right-of-way is
provided by an existing gravel access drive, currently used by the NCSTATE agricultural
program to test crops planted in the flood plain.
The Town of Mills River does not currently participate in the FEMA FIRM program, thus a
floodplain development permit is not required by the Town or County.
As-built Conditions
The substation site was construction as described above with outlined changes from the original
project summary. The site is split into two (2) separate drainage basins according to the pre and
post topography. Drainage Area 1 (DA-1) encompasses the adjacent property and areas due to
the POA at the French Broad River. The development proposed on the adjacent property is not
considered as part of the analysis for the Ferncliff Ret project and this shall be separately
analyzed by the developer for their contributing post-construction runoff. The portion of the
subdivided substation parcel draining to DA-1 was anlayzed with the post-construction
conditions described above. Drainage Area 2 (DA-2) drains towards Broadpointe Drive to a
ditchline, that ultimately drains to the same POA as DA-1. The runoff comparison pre and post
was analyzed separately using the Hydraflow Hydrographs Extension in AutoCAD 2020. Due to
the site contributing runoff to the same POA location the overall combined pre and post-
development was compared for this project. The overall post-construction runoff from the project
site with the added surface conditions were proven to be less than the pre-construction runoff
values for substation parcel. Please see Table 1.1 below with the comparison values along with
the routing information provided within the Routing Calculations section.

Table 1.1:Pre &Post-Construction Runoff&Routing
I Drainage Tc I I I 2-YR I 10-YR 25-YR I 100-YR
Area Sub-basin (min) I CN I Area (ac) I Runoff values in CFS
DA-1A PRE 9.70 72 23.73 44.23 97.41 1 131.40 221.29
DA 1 PRE DA-1B PRE 8.60 61 2.12 1.773 5.550 8.101 15.28
DA-1C PRE 7.30 61 2.25 1.882 5.890 8.598 16.22
COMBINED DA-1 - - 28.10 47.89 108.73 147.84 252.79
DA-2 5.60 61 2.42 2.291 6.878 9.955 18.54
COMBINED SITE (DA-1 & DA-2) - - 30.52 49.90 115.39 157.79 271.30
DA-1A POST 9.70 71 24.07 42.45 95.42 129.45 220.17
DA-1B POST 5.00 62 4.14 4.293 12.34 17.69 32.59
VEG SWALES - - - 3.571 11.33 16.67 31.55
(ROUTED BY DA-
DA-1 POST 1B) _
DETENTION AREA - - - 3.163 8.342 11.40 29.89
(ROUTED FROM
VEG SWALES)
COMBINED DA-1 - - 28.21 44.29 102.37 129.45 220.17
DA-2 POST DA-2 5.00 68 2.32 3.730 8.843 12.09 _ 21.10
FR VEG SWALE - - - 3.612 8.784 12.06 20.95
(ROUTED BY DA-2)
COMBINED SITE (DA-1 & DA-2) - - 30.54 47.90 111.16 150.39 266.94

Engineering Design As-Built
Supporting Documentation

USDA United States A product of the National Custom Soil Resource
Department of Cooperative Soil Survey,
Agriculture a joint effort of the United Report for
States Department of
RC S Agriculture and other Henderson County
Federal agencies, State
Naturalagencies including the North Carolina
Resources Agricultural Experiment
Conservation Stations, and local
Service participants
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October 15, 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.nrcs.usda.gov/wps/
portal/nrcs/main/soils/health/) and certain conservation and engineering
applications. For more detailed information, contact your local USDA Service Center
(https://offices.sc.egov.usda.gov/locator/app?agency=nrcs)or your NRCS State Soil
Scientist(http://www.nres.usda.gov/wps/portal/nres/detail/soils/contactus/?
cid=nrcs142p2_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
2

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(202) 720-6382 (TDD). USDA is an equal opportunity
provider and employer.
3

Contents
Preface 2
How Soil Surveys Are Made 5
Soil Map 8
Soil Map 9
Legend 10
Map Unit Legend 11
Map Unit Descriptions 11
Henderson County, North Carolina 13
BaB—Bradson gravelly loam, 2 to 7 percent slopes 13
Co—Codorus loam (arkaqua) 14
Cu—Comus (colvard)fine sandy loam 15
EnB—Elsinboro loam, 0 to 3 percent slopes 16
Ro—Rosman loam 17
Soil Information for All Uses 19
Soil Properties and Qualities 19
Soil Qualities and Features 19
Hydrologic Soil Group (Ferncliff Ret Site (Mills River, NC)) 19
References 24
4

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
5

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
6

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.
7

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.
8

Custom Soil Resource Report
N Soil Map
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M Map Scale:1:4,060 if printed on A portrait(8.5"x 11")sheet N
Meters
m N 0 50 100 200 300
A Feet
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Map projection:Web Mercator Comer coordinates:WG584 Edge tics:UTM Zone 17N WGS84
9

Custom Soil Resource Report
MAP LEGEND MAP INFORMATION
Area of Interest(AOI) 14 Spoil Area The soil surveys that comprise your AOI were mapped at
Area of Interest(AOI) 1:20,000.
Q Stony Spot
Soilsit Very Stony Spot
Soil Map Unit Polygons Warning:Soil Map may not be valid at this scale.
V. Wet Spot
,..,. Soil Map Unit Lines Enlargement of maps beyond the scale of mapping can cause
p Other misunderstandingof the detail of mapping and accuracyof soil
p Soil Map Unit Points pp 9
.� Special Line Features line placement.The maps do not show the small areas of
Special Point Features contrasting soils that could have been shown at a more detailed
Blowout Water Features scale.
Streams and Canals
kg Borrow Pit
Transportation Please rely on the bar scale on each map sheet for map
* clay Spot 1.44 Rails measurements.
0 Closed Depression
pu/ Interstate Highways
Gravel Pit Source of Map: Natural Resources Conservation Service
ti US Routes Web Soil Survey URL:
Gravelly Spot Major Roads Coordinate System: Web Mercator(EPSG:3857)
® Landfill Local Roads Maps from the Web Soil Survey are based on the Web Mercator
• Lava Flow Background projection,which preserves direction and shape but distorts
distance and area.A projection that preserves area,such as the
46 Marsh or swamp Aerial Photography Albers equal-area conic projection,should be used if more
It Mine or Quarry accurate calculations of distance or area are required.
4 Miscellaneous Water This product is generated from the USDA-NRCS certified data as
O Perennial Water of the version date(s)listed below.
v Rock Outcrop Soil Survey Area: Henderson County, North Carolina
+ Saline Spot Survey Area Data: Version 20,Jun 4,2020
Sandy Spot Soil map units are labeled(as space allows)for map scales
Severely Eroded Spot 1:50,000 or larger.
• Sinkhole Date(s)aerial images were photographed: May 3,2020—May 7,
31 Slide or Slip 2020
oa Sodic Spot The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps.As a result,some minor
shifting of map unit boundaries may be evident.
10

Custom Soil Resource Report
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
BaB Bradson gravelly loam,2 to 7 12.5 35.7%
percent slopes
Co Codorus loam(arkaqua) 1.0 2.9%
Cu Comus(colvard)fine sandy 6.3 18.0%
loam
EnB Elsinboro loam,0 to 3 percent 11.5 33.0%
slopes
Ro Rosman loam 3.6 10.4%
Totals for Area of Interest 35.0 100.0%
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.
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Custom Soil Resource Report
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 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
Henderson County, North Carolina
BaB—Bradson gravelly loam, 2 to 7 percent slopes
Map Unit Setting
National map unit symbol: Ic10
Elevation: 900 to 3,500 feet
Mean annual precipitation: 40 to 80 inches
Mean annual air temperature: 50 to 57 degrees F
Frost-free period: 150 to 180 days
Farmland classification: All areas are prime farmland
Map Unit Composition
Bradson and similar soils: 90 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Bradson
Setting
Landform: Stream terraces, fans
Landform position (two-dimensional): Summit
Landform position (three-dimensional):Tread
Down-slope shape: Convex
Across-slope shape: Convex
Parent material: Old alluvium and/or old colluvium derived from igneous and
metamorphic rock
Typical profile
Ap-0 to 6 inches: gravelly loam
Bt- 6 to 65 inches: clay loam
C- 65 to 80 inches: loam
Properties and qualities
Slope: 2 to 7 percent
Depth to restrictive feature: More than 80 inches
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 capacity: Moderate (about 8.6 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 2s
Hydrologic Soil Group: B
Hydric soil rating: No
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Custom Soil Resource Report
Co—Codorus loam (arkaqua)
Map Unit Setting
National map unit symbol: Ic18
Elevation: 1,200 to 2,000 feet
Mean annual precipitation: 45 to 70 inches
Mean annual air temperature: 46 to 57 degrees F
Frost-free period: 116 to 170 days
Farmland classification: Prime farmland if drained and either protected from flooding
or not frequently flooded during the growing season
Map Unit Composition
Arkaqua, frequently flooded, and similar soils:90 percent
Minor components: 5 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Arkaqua, Frequently Flooded
Setting
Landform: Flood plains
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Loamy alluvium
Typical profile
Ap- 0 to 9 inches: loam
Bw-9 to 30 inches: clay loam
Bg-30 to 46 inches: sandy clay loam
Cg-46 to 80 inches: loam
Properties and qualities
Slope: 0 to 2 percent
Depth to restrictive feature:44 to 72 inches to strongly contrasting textural
stratification
Drainage class: Somewhat poorly drained
Runoff class: Low
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:About 18 to 24 inches
Frequency of flooding: OccasionalNone
Frequency of ponding: None
Available water capacity: Moderate (about 7.4 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 4w
Hydrologic Soil Group: B/D
Hydric soil rating: No
14

Custom Soil Resource Report
Minor Components
Toxaway, undrained
Percent of map unit: 5 percent
Landform: Depressions on flood plains
Down-slope shape: Linear, concave
Across-slope shape: Concave
Hydric soil rating: Yes
Cu—Comus (colvard) fine sandy loam
Map Unit Setting
National map unit symbol: Ic19
Elevation: 500 to 2,000 feet
Mean annual precipitation: 38 to 65 inches
Mean annual air temperature: 48 to 57 degrees F
Frost-free period: 140 to 200 days
Farmland classification: Prime farmland if protected from flooding or not frequently
flooded during the growing season
Map Unit Composition
Colvard and similar soils: 90 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Colvard
Setting
Landform: Natural levees on flood plains
Down-slope shape: Convex
Across-slope shape: Convex
Parent material: Sandy and loamy alluvium derived from igneous and
metamorphic rock
Typical profile
H1 - 0 to 20 inches: fine sandy loam
H2- 20 to 36 inches: fine sandy loam
H3-36 to 70 inches: loamy sand
Properties and qualities
Slope: 0 to 2 percent
Depth to restrictive feature: More than 80 inches
Drainage class:Well drained
Runoff class: Very low
Capacity of the most limiting layer to transmit water(Ksat): High (1.98 to 5.95
in/hr)
Depth to water table:About 30 to 42 inches
Frequency of flooding: FrequentNone
Frequency of ponding: None
Available water capacity: Low(about 5.9 inches)
15

Custom Soil Resource Report
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 2w
Hydrologic Soil Group: B
Hydric soil rating: No
EnB—Elsinboro loam, 0 to 3 percent slopes
Map Unit Setting
National map unit symbol: Ic1 h
Elevation: 0 to 1,000 feet
Mean annual precipitation: 38 to 46 inches
Mean annual air temperature: 50 to 55 degrees F
Frost-free period: 150 to 210 days
Farmland classification: All areas are prime farmland
Map Unit Composition
Elsinboro and similar soils: 90 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Elsinboro
Setting
Landform: Stream terraces
Landform position (two-dimensional): Summit, shoulder
Landform position (three-dimensional):Tread
Down-slope shape: Linear
Across-slope shape: Convex
Parent material: Old alluvium derived from igneous and metamorphic rock and/or
old colluvium
Typical profile
H1 - 0 to 15 inches: loam
H2- 15 to 36 inches: loam
H3-36 to 60 inches: sandy loam
Properties and qualities
Slope: 0 to 3 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 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 capacity: Moderate (about 7.4 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 1
Hydrologic Soil Group: B
16

Custom Soil Resource Report
Hydric soil rating: No
Ro—Rosman loam
Map Unit Setting
National map unit symbol: Ic20
Elevation: 1,200 to 2,000 feet
Mean annual precipitation: 45 to 70 inches
Mean annual air temperature: 46 to 57 degrees F
Frost-free period: 116 to 170 days
Farmland classification: Prime farmland if protected from flooding or not frequently
flooded during the growing season
Map Unit Composition
Rosman, frequently flooded, and similar soils: 90 percent
Minor components: 5 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Rosman, Frequently Flooded
Setting
Landform: Flood plains
Down-slope shape: Linear
Across-slope shape: Linear
Parent material: Loamy alluvium
Typical profile
A -0 to 16 inches: fine sandy loam
Bw- 16 to 80 inches: loam
Properties and qualities
Slope: 0 to 2 percent
Depth to restrictive feature: More than 80 inches
Drainage class:Well drained
Runoff class: Very low
Capacity of the most limiting layer to transmit water(Ksat): High (1.98 to 5.95
in/hr)
Depth to water table:About 42 to 60 inches
Frequency of flooding: FrequentNone
Frequency of ponding: None
Available water capacity: Moderate (about 8.5 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 6w
Hydrologic Soil Group: A
Hydric soil rating: No
Minor Components
Hemphill, undrained
Percent of map unit: 5 percent
Landform: Depressions on stream terraces
17

Custom Soil Resource Report
Down-slope shape: Concave
Across-slope shape: Concave
Hydric soil rating: Yes
18

Soil Information for All Uses
Soil Properties and Qualities
The Soil Properties and Qualities section includes various soil properties and
qualities displayed as thematic maps with a summary table for the soil map units in
the selected area of interest. A single value or rating for each map unit is generated
by aggregating the interpretive ratings of individual map unit components. This
aggregation process is defined for each property or quality.
Soil Qualities and Features
Soil qualities are behavior and performance attributes that are not directly
measured, but are inferred from observations of dynamic conditions and from soil
properties. Example soil qualities include natural drainage, and frost action. Soil
features are attributes that are not directly part of the soil. Example soil features
include slope and depth to restrictive layer. These features can greatly impact the
use and management of the soil.
Hydrologic Soil Group (Ferncliff Ret Site (Mills River,
NC))
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive precipitation
from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential)when thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well drained
soils that have moderately fine texture to moderately coarse texture. These soils
have a moderate rate of water transmission.
19

Custom Soil Resource Report
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of water
transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential)when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay layer at
or near the surface, and soils that are shallow over nearly impervious material.
These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in their
natural condition are in group D are assigned to dual classes.
20

Custom Soil Resource Report
N Map—Hydrologic Soil Group (Ferncliff Ret Site (Mills River, NC)) 3
M N
N N
358800 35859) 359000 359100 359200 359300
35°25'47"N 35°25'47'N
8
f
re...
8 eroa�R'` S
r e,.
T
_ N. 2S
N
r: � - C Ro
e
R lip, ,., <4"
14
:_ t —
M
d
N eo
"Co o
T,A1 , ma,; 1"),h eSilIV ate afr&0c�a0�°
35°25'20"N ,11111111111r1s.._ I —§ 35°25'20"N
358800 358900 359000 359100 359200 359300
3 3
Map Scale:1:4,060 if printed on A portrait(8.5"x 11")sheet. N
Meters
gO N 0 50 100 200 300
Feet
0 150 300 600 900
Map pmjedion:Web Mercator Comer coordinates:WGS84 Edge tics:UTM Zone 17N WGS84
21

Custom Soil Resource Report
MAP LEGEND MAP INFORMATION
Area of Interest(AOI) 0 C The soil surveys that comprise your AOI were mapped at
Area of Interest(AOI) CID 1:20,000.
Soils D
Soil Rating Polygons Warning:Soil Map may not be valid at this scale.
A 0 Not rated or not available
Enlargement of maps beyond the scale of mapping can cause
I Water Features
A/D misunderstanding of the detail of mapping and accuracy of soil
1 Streams and Canals line placement.The maps do not show the small areas of
I I B
Transportation contrasting soils that could have been shown at a more detailed
I B/D scale.
1-FF Rails
I C
^,/ Interstate Highways
C/D Please rely on the bar scale on each map sheet for map
~iv US Routes measurements.
D Major Roads
Not rated or not available Source of Map: Natural Resources Conservation Service
Local Roads Web Soil Survey URL:
Soil Rating Lines Background Coordinate System: Web Mercator(EPSG:3857)
• Ael Aerial Photography
Maps from the Web Soil Survey are based on the Web Mercator
. • A/D projection,which preserves direction and shape but distorts
• B distance and area.A projection that preserves area,such as the
Albers equal-area conic projection,should be used if more
....we B/D accurate calculations of distance or area are required.
✓ w c
This product is generated from the USDA-NRCS certified data as
• r C/D of the version date(s)listed below.
. r D
Soil Survey Area: Henderson County, North Carolina
• Not rated or not available Survey Area Data: Version 20,Jun 4,2020
Soil Rating Points
A Soil map units are labeled(as space allows)for map scales
1:50,000 or larger.
▪ A/D
▪ B Date(s)aerial images were photographed: May 3,2020—May 7,
2020
▪ B/D
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps.As a result,some minor
shifting of map unit boundaries may be evident.
22

Custom Soil Resource Report
Table—Hydrologic Soil Group (Ferncliff Ret Site (Mills River, NC))
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
BaB Bradson gravelly loam,2 B 12.5 35.7%
to 7 percent slopes
Co Codorus loam(arkaqua) B/D 1.0 2.9%
Cu Comus(colvard)fine B 6.3 18.0%
sandy loam
EnB Elsinboro loam,0 to 3 B 11.5 33.0%
percent slopes
Ro Rosman loam A 3.6 10.4%
Totals for Area of Interest 35.0 100.0%
Rating Options—Hydrologic Soil Group (Ferncliff Ret Site (Mills
River, NC))
Aggregation Method: Dominant Condition
Component Percent Cutoff.None Specified
Tie-break Rule: Higher
23

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/
nres/detail/national/soils/?cid=nres 142p2_054262
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.nrcs.usda.gov/wps/portal/nrcs/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/rangepasture/?cid=stelprdb1043084
24

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/
nres/detail/soils/scientists/?cid=nres142p2_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=nres142p2_053624
United States Department of Agriculture, Soil Conservation Service. 1961. Land
capability classification. U.S. Department of Agriculture Handbook 210. http://
www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf
25

NOAA Atlas 14,Volume 2,Version 3
`"`°`N Location name: Mills River,North Carolina,USA* -"-
Latitude:35.3908°,Longitude: -82.568° € norm ?•.
Elevation:m/ft**
'��� *source:ESRI Maps '',,q, *
`a **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)
Duration
1 I 2 I 5 I 10 25 50 100 200 500 1000
5-minI I
4.44 5.28 6.32 7.12 8.15 8.94 9.73 10.5 11.5 12.4
(4 00-4 93) (4 76-5 86) (5 70-7 02) (6 40-7 88) (7 27-9 01) (7 93-9 88) (8.59-10.8) (9.23-11.7) (10.0-12.9) (10.6-13.9)
10-min 3.55 4.22 5.06 5.69 6.49 7.12 7.73 8.34 9.13 9.74
(3.20-3.94) (3.82-4.69) (4.57-5.62) (5.12-6.30) (5.80-7.18) (6.31-7.87) (6.83-8.56) (7.31-9.26) (7.91-10.2) (8.36-11.0)
15-min 2.95 3.54 4.27 4.80 5.49 6.01 6.51 7.01 7.66 8.16
(2.66-3.28) (3.20-3.93) (3.85-4.74) (4.32-5.31) (4.90-6.07) (5.33-6.64) (5.75-7.22) (6.15-7.79) (6.64-8.56) (7.00-9.17)
30-min 2.02 2.44 3.03 3.48 4.06 4.52 4.99 5.46 6.10 6.60
(1.83-2.25) (2.21-2.71) (2.73-3.37) (3.13-3.85) (3.63-4.50) (4.01-5.00) (4.41-5.53) (4.79-6.06) (5.28-6.82) (5.66-7.42)
60-min 1.26 1.53 1.94 2.26 2.71 3.07 3.44 3.83 4.37 4.82
(1.14-1.40) (1.39-1.70) (1.75-2.16) (2.04-2.51) (2.41-2.99) (2.72-3.39) (3.03-3.81) (3.36-4.25) (3.79-4.89) (4.13-5.42)
2-hr 0.741 0.900 1.14 1.32 1.59 1.80 2.03 2.27 2.60 2.88
(0.668-0.822) (0.812-0.996) (1.02-1.25) (1.19-1.46) (1.41-1.76) (1.59-1.99) (1.78-2.25) (1.97-2.52) (2.24-2.90) (2.45-3.23)
3-hr 0.531 0.640 0.802 0.935 1.13 1.29 1.46 1.65 1.92 2.14
(0.480-0.592) (0.577-0.712) (0.722-0.891) (0.838-1.04) (1.00-1.25) (1.14-1.43) (1.28-1.63) (1.43-1.84) (1.64-2.15) (1.80-2.42)
6-hr 0.339 0.404 0.498 0.579 0.695 0.795 0.903 1.02 1.19 1.34
(0.310-0.373) (0.369-0.444) (0.454-0.547) (0.525-0.636) (0.626-0.764) (0.710-0.873) (0.798-0.994) (0.891-1.13) (1.02-1.32) (1.13-1.49)
12-hr 0.211 0.252 0.310 0.356 0.420 0.473 0.527 0.584 0.663 0.727
(0.194-0.231) (0.232-0.276) (0.284-0.338) (0.326-0.389) (0.382-0.459) (0.429-0.516) (0.475-0.577) (0.522-0.642) (0.586-0.734) (0.636-0.810)
24-hr 0.127 0.152 0.187 0.214 0.253 0.284 0.316 0.349 0.395 0.432
(0.118-0.137) (0.141-0.165) (0.173-0.202) (0.198-0.232) (0.233-0.273) (0.260-0.306) (0.288-0.340) (0.317-0.376) (0.356-0.427) (0.386-0.468)
2-day 0.075 0.090 0.109 0.125 0.146 0.164 0.181 0.200 0.225 0.245
(0.070-0.081) (0.084-0.097) (0.102-0.118) (0.116-0.134) (0.136-0.157) (0.151-0.176) (0.167-0.195) (0.183-0.215) (0.204-0.243) (0.221-0.265)
3-day 0.054 0.064 0.077 0.088 0.102 0.113 0.125 0.137 0.153 0.166
(0.050-0.057) (0.060-0.068) (0.072-0.083) (0.082-0.094) (0.095-0.109) (0.105-0.121) (0.115-0.134) (0.125-0.147) (0.139-0.164) (0.150-0.179)
4-day 0.043 0.051 0.061 0.069 0.080 0.088 0.096 0.105 0.116 0.126
(0.040-0.046) (0.048-0.054) (0.057-0.065) (0.064-0.074) (0.074-0.085) (0.082-0.094) (0.089-0.103) (0.097-0.112) (0.107-0.125) (0.114-0.135)
7-day 0.029 0.034 0.041 0.046 0.053 0.059 0.065 0.071 0.079 0.085
(0.027-0.031) (0.032-0.036) (0.038-0.043) (0.043-0.049) (0.050-0.057) (0.055-0.063) (0.060-0.069) (0.065-0.076) (0.072-0.085) (0.078-0.092)
10-day 0.023 0.027 0.032 0.036 0.042 0.046 0.050 0.054 0.060 0.065
(0.022-0.024) (0.026-0.029) (0.030-0.034) (0.034-0.038) (0.039-0.044) (0.043-0.049) (0.047-0.053) (0.051-0.058) (0.056-0.064) (0.060-0.070)
20-day 0.016 0.018 0.021 0.023 0.026 0.029 0.031 0.033 0.036 0.038
(0.015-0.016) (0.017-0.019) (0.020-0.022) (0.022-0.025) (0.025-0.028) (0.027-0.030) (0.029-0.033) (0.031-0.035) (0.033-0.038) (0.035-0.040)
30-day 0.013 0.015 0.017 0.019 0.021 0.022 0.024 0.025 0.027 0.028
(0.012-0.013) (0.014-0.016) (0.016-0.018) (0.018-0.020) (0.020-0.022) (0.021-0.023) (0.022-0.025) (0.024-0.026) (0.025-0.028) (0.026-0.029)
45-day 0.011 0.013 0.014 0.015 0.017 0.018 0.019 0.019 0.020 0.021
(0.010-0.011) (0.012-0.013) (0.014-0.015) (0.015-0.016) (0.016-0.018) (0.017-0.019) (0.018-0.020) (0.018-0.020) (0.019-0.022) (0.020-0.022)
60-day 0.010 0.011 0.013 0.014 0.015 0.015 0.016 0.017 0.018 0.018
(0.009-0.010) (0.011-0.012) (0.012-0.013) (0.013-0.014) (0.014-0.015) (0.015-0.016) (0.015-0.017) (0.016-0.018) (0.017-0.018) (0.017-0.019)
1 Precipitation frequency(PF)estimates in this table are based on frequency analysis of partial duration series(PDS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90%confidence interval.The probability that precipitation frequency estimates(for
a given duration and average recurrence interval)will be greater than the upper bound(or less than the lower bound)is 5%.Estimates at upper bounds are not
checked against probable maximum precipitation(PMP)estimates and may be higher than currently valid PMP values.
Please refer to NOAAAtlas 14 document for more information.
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PF graphical
PDS-based intensity-duration-frequency(IDF)curves
Latitude: 35.3908°,Longitude:-82.5680°
100.000 I 1 I I I I I I I I I
Average recurrence
interval
10-000 = _ - (years)
L
— 1
.71 1.000 - ���- — 5
c — 25
o
0.100 — 50
_____
a — too
u_ 0.010 -
500
— 1000
0.001 1_
C C C C C I- t E I >, >,>, A >, >, > >,>,
E E •E E •E L L - . . rp r0 r0 r0 r0 N r0 r0 3
N f�1 lb N V "O "O"O 9 "O "O "O "O"O
V1 O in O "'I N N A 4 1` O O O in
,--1 ,-I rrl ID r-I N NI 1-ID
Duration
100-000 I I I I
10.000
_c
C _
Duration
.c L000 - — 5-min — 2-day
— 10-min — 3-day
c 15-min — 4-day
•° 0-100 — 30-min — 7-day
y
a — 60-min — 10-day
— 2-hr — 20-day
m
a` 0.010 - — 3-hr — 30-day
— 6-hr — 45-day
— 12-hr — 60-clay
0.001 — 24-hr
1 2 5 10 25 50 100 200 500 1000
Average recurrence interval(years)
NOAA Atlas 14,Volume 2,Version 3 Created(GMT):Thu Aug 6 13:48:15 2020
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Maps & aerials
Small scale terrain
Fletcher.
Hi'
KNOB :
, I::-
:•,• •
I- a, —.....*;.\i`
I
MOU El 01
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MIL/NT/LIN ''',: -1
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2mi jOHN
Large scale terrain
'...) Kingsport Bristol
: '''• \I.
IZs Johnson City ,)
Winston-Sale
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Knoxville q
(
i- tit Mitchell
CZ CI` -,,[•,.' .7,,
tA•-.1.•0, .• r Asheville
NORTH C
v I
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soya „6
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(
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60mi ?
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Large scale map
—7...... . _KingSpoOrt pjsfol
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7
i
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10
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Lar.e scale aerial
✓~ Kingsport_..sristol
• Johnson Ci
Winston-
Knoxville
• Asheville
• C harlot
oga
v\
Greenville
• i_
Ilk
Cdurribi8
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National Oceanic and Atmospheric Administration
National Weather Service
National Water Center
1325 East West Highway
Silver Spring,MD 20910
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NOAA Atlas 14,Volume 2,Version 3
`°°°` Location name: Mills River,North Carolina,USA* � '
Latitude:35.3908°,Longitude: -82.568° € norm •
Elevation:m/ft**
'��� *source:ESRI Maps 'v,,,,, *'
`a **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 2 5 10 25 50 100 200 500 1000
5-min 0.370 0.440 0.527 0.593 0.679 0.745 0.811 0.877 0.962 1.03
(0.333-0.411) (0.397-0.488) (0.475-0.585 (0.533-0.657) (0.606-0.751) 0.661-0.823) (0.716-0.898) (0.769-0.974) (0.834-1.08) (0.885-1.16)
10-min 0.591 0.704 0.844 0.949 1.08 1.19 1.29 1.39 1.52 1.62
(0.533-0.656) (0.636-0.781) (0.761-0.937 (0.853-1.05) (0.966-1.20) (1.05-1.31) (1.14-1.43) (1.22-1.54) (1.32-1.70) (1.39-1.83)
15-min 0.738 0.885 1.07 1.20 1.37 1.50 1.63 1.75 1.92 2.04
(0.666-0.820) (0.799-0.982) (0.962-1.19) (1.08-1.33) (1.22-1.52) (1.33-1.66) (1.44-1.80) (1.54-1.95) (1.66-2.14) (1.75-2.29)
30-min 1.01 1.22 1.52 1.74 2.03 2.26 2.49 2.73 3.05 3.30
(0.913-1.12) (1.10-1.36) (1.37-1.68) (1.56-1.93) (1.81-2.25) (2.01-2.50) (2.20-2.76) (2.39-3.03) (2.64-3.41) (2.83-3.71)
60-min 1.26 1.53 1.94 2.26 2.71 3.07 3.44 3.83 4.37 4.82
(1.14-1.40) (1.39-1.70) (1.75-2.16) (2.04-2.51) (2.41-2.99) (2.72-3.39) (3.03-3.81) (3.36-4.25) (3.79-4.89) (4.13-5.42)
2-hr 1.48 1.80 2.27 2.65 3.17 3.60 4.05 4.53 5.20 5.75
(1.34-1.64) (1.62-1.99) (2.04-2.51) (2.37-2.92) (2.82-3.51) (3.18-3.99) (3.56-4.49) (3.94-5.03) (4.47-5.81) (4.89-6.46)
3-hr 1.60 1.92 2.41 2.81 3.39 3.88 4.39 4.96 5.76 6.44
(1.44-1.78) (1.73-2.14) (2.17-2.68) (2.52-3.12) (3.01-3.76) (3.42-4.31) (3.84-4.88) (4.29-5.52) (4.91-6.47) (5.42-7.26)
6-hr 2.03 2.42 2.98 3.47 4.16 4.76 5.41 6.11 7.14 8.01
(1.85-2.23) (2.21-2.66) (2.72-3.28) (3.14-3.81) (3.75-4.58) (4.25-5.23) (4.78-5.95) (5.34-6.74) (6.13-7.92) (6.79-8.94)
12-hr 2.55 3.04 3.73 4.29 5.06 5.69 6.35 7.03 7.99 8.75
(2.34-2.78) (2.79-3.32) (3.42-4.08) (3.92-4.68) (4.61-5.53) (5.16-6.22) (5.72-6.95) (6.29-7.73) (7.07-8.85) (7.67-9.76)
24-hr 3.04 3.65 I 4.48 5.14 6.06 6.81 7.57 8.37 9.48 10.4
(2.82-3.29) (3.38-3.95) i (4.15-4.85) (4.76-5.56) (5.59-6.55) (6.25-7.35) (6.92-8.16) (7.60-9.03) (8.54-10.2) (9.25-11.2)
2-day 3.62 4.32 5.26 6.00 7.03 7.86 8.71 9.59 10.8 11.8
(3.38-3.89) (4.02-4.65) (4.89-5.65) (5.58-6.45) (6.51-7.55) (7.25-8.43) (8.01-9.36) (8.77-10.3) (9.81-11.7) (10.6-12.7)
3-day 3.86 4.60 5.55 6.31 7.33 8.15 8.98 9.83 11.0 11.9
(3.61-4.14) (4.30-4.93) (5.18-5.95) (5.88-6.75) (6.81-7.85) (7.55-8.72) (8.29-9.63) (9.03-10.6) (10.0-11.8) (10.8-12.9)
4-day 4.11 4.89 5.85 6.61 7.64 8.44 9.26 10.1 11.2 12.1
(3.84-4.38) (4.57-5.22) (5.47-6.24) (6.18-7.06) (7.11-8.15) (7.84-9.01) (8.56-9.89) (9.28-10.8) (10.2-12.0) (11.0-13.0)
7-day 4.80 5.69 6.82 7.72 8.93 9.90 10.9 11.9 13.3 14.3
(4.50-5.13) (5.34-6.10) (6.39-7.30) (7.22-8.25) (8.32-9.55) (9.20-10.6) (10.1-11.6) (11.0-12.7) (12.1-14.2) (13.0-15.4)
10-day 5.50 6.50 7.71 8.66 9.96 11.0 12.0 13.1 14.5 15.6
(5.19-5.83) (6.13-6.91) (7.28-8.19) (8.17-9.20) (9.36-10.6) (10.3-11.7) (11.2-12.8) (12.2-13.9) (13.4-15.5) (14.3-16.7)
20-day 7.46 8.77 10.2 11.3 12.7 13.8 14.8 15.8 17.1 18.1
(7.07-7.88) (8.32-9.27) (9.65-10.8) (10.7-11.9) (12.0-13.4) (13.0-14.6) (14.0-15.7) (14.9-16.8) (16.0-18.2) (16.9-19.3)
30-day 9.15 10.7 12.3 13.4 14.9 16.0 17.0 18.0 19.2 20.0
(8.69-9.63) (10.2-11.3) (11.7-12.9) (12.7-14.1) (14.1-15.7) (15.1-16.8) (16.1-17.9) (16.9-19.0) (18.0-20.3) (18.8-21.2)
45-day 11.6 13.6 15.3 16.6 18.1 19.2 20.1 21.0 22.1 22.8
(11.1-12.2) (13.0-14.3) (14.6-16.1) (15.8-17.4) (17.2-19.0) (18.2-20.1) (19.1-21.2) (19.9-22.1) (20.9-23.2) (21.5-24.0)
60-day 14.0 16.3 18.2 19.5 21.2 22.3 23.3 24.2 25.3 26.0
(13.3-14.7) (15.5-17.1) (17.3-19.1) (18.6-20.5) (20.2-22.2) (21.2-23.4) (22.2-24.5) (23.0-25.5) (23.9-26.6) (24.6-27.4)
1 Precipitation frequency(PF)estimates in this table are based on frequency analysis of partial duration series(PDS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90%confidence interval.The probability that precipitation frequency estimates
(for a given duration and average recurrence interval)will be greater than the upper bound(or less than the lower bound)is 5%.Estimates at upper bounds
are not checked against probable maximum precipitation(PMP)estimates and may be higher than currently valid PMP values.
Please refer to NOAAAtlas 14 document for more information.
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PF graphical
PDS-based depth-duration-frequency(DDF) curves
Latitude: 35.3908°,Longitude:-82.5680°
30 1 1 I
Average recurrence
25 ii:
c
_c 20 _....
a
ai •
•
•
'C C C C C i T T T A T T T T T
E •E 'E ' E L L L L L r0 00 00 (0 00 (0 00 (0 00E
V1 O V1 O O -1 N N A 4 r` OO O O u1 O
rl rl r0 l0 rl N fr1 1 ID
Duration
30 I I I
25
c
L
20 Duration
J-I
aai — 5-min — I
co 15 - — 10-min —
15-min
+° — 30-min —
10 — 60-min —
o — 2-hr —
•
5 •
— 3-hr —
•
— 6-ty —
— 12-hr —
0 I i — 24fir
1 2 5 10 25 50 100 200 500 1000
Average recurrence interval(years)
NOAA Atlas 14,Volume 2,Version 3 Created(GMT):Thu Aug 6 13:47.19 2020
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Maps & aerials
Small scale terrain
Fletcher.
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KNOB :
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Large scale map
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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

Storm Drainage — Conveyance Design

DUKE ENERGY 526 S Church Street
Charlotte,NC 28202
Transmission Engineering
Ferncliff Ret
Station Number: 5574 iltI
10/16/20 JAP Storm Drainage Calculations-Conveyance Only-(10&25 year storms)
2/16/23 JAP
:M.11111=r -7.-
Storm Runoff ipe Sizing Calculations
IIMMMIll
Percent Percent Composite Inlet Combined Pipe Pipe Pipe
Pipe Slope Dtheo Vfull Capacity Time Actual
acres Pervious Impervious Runoff I(in/hr) Discharge Q Discharge Material n Length Size(in) Q/Q-full d/dm ratio v/V-full
Structure Structure (/oo) (in) (fps) Q-full Actual (min)- Pipe Structure Pipe
(%) (%) Coeff.Cc (cfs) Qpipe(cfs) (ft) (cfs) Vpipe Full Time Rim Depth Of Cover Pipe Material
(fps) Cond. (min) Pipe Inv.In Pipe Inv.Out Elevation (Based on Rim) Material Class
Storm Network-10-Yr/24-Hr Design(As-built) MI
DI-108 DI-107 0.12 10% 90% 0.84 7.12 0.7 0.7 0.012 0.910/0 43.93 6.5 12 4.7 3.69 0.20 0.25 0.66 3.10 0.16 0.24 2072.70 2072.30 2075.89 1.94 HDPE -
DI-107 I DI-106 I 0.23 I 10% I 90% I 0.84 I 7.12 I 1.3 I 2.1 I 0.012 I 1.07% I 55.98 I 9.4 I 12 I 5.1 I 4.01 I 0.52 I 0.50 I 0.99 I 5.05 I 0.34 I 0.42 I 2072.30 I 2071.70 I 2075.98 I 2.43 I HDPE I -
DI-106 DI-105 0.20 10% 90% 0.84 7.12 1.2 3.3 0.012 0.02% 59.64 24.2 15 0.7 0.91 3.58 1.00 1.00 0.74 1.68 1.76 2071.70 2071.69 2075.94 2.74 HDPE -
DI-105 JB-104 0.15 10% 90% 0.84 7.12 0.9 4.2 0.012 2.70% 55.28 10.2 15 9.4 11.52 0.36 0.40 0.87 8.17 1.78 1.88 2071.69 2070.20 2075.62 2.43 HDPE -
JB-104 I OWS I 0.00 I 0% I 1000/0 I 0.90 I 7.12 I 0.0 I 4.2 I 0.010 I 0.00% I 20.68 I 10.2 I 16 I 0.0 I 0.00 I 0.00 I 0.00 I 0.00 I 0.00 I 0.00 I 0.00 I 2069.90 I 2069.90 I 2075.55 I 4.32 I DIP I -
OWS 3B-103 0.00 0% 100% 0.90 7.12 0.0 4.2 0.010 0.00% 17.06 10.2 16 0.0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2069.90 2069.90 2076.12 4.89 DIP -
JB-103 I JB-102 I 0.00 I 0% I 100% I 0.90 I 7.12 I 0.0 I 4.2 I 0.012 I 0.54% I 74.15 I 13.9 I 18 I 4.7 I 8.38 I 0.50 I 0.45 I 0.94 I 4.46 I 0.26 I 0.28 I 2069.80 I 2069.40 I 2075.82 I 4.23 I HDPE I -
JB-102 FES-101 0.00 0% 100% 0.90 7.12 0.0 4.2 0.012 2.01% 80.63 10.8 18 9.2 16.17 0.26 0.30 0.74 6.77 0.41 0.48 2069.20 2067.58 2072.00 1.01 HDPE -
Storm Network-25-Yr/24-Hr Design(As-built) IR
DI-108 DI-107 0.12 10% 90% 0.84 8.15 0.8 0.8 0.012 0.91% 43.93 6.9 12 4.7 3.69 0.23 0.30 0.74 3.48 0.16 0.21 2072.70 2072.30 2075.89 1.94 HDPE -
DI-107 DI-106 0.23 10% 90% 0.84 8.15 1.5 2.4 0.012 1.07% 55.98 9.9 12 5.1 4.01 0.60 0.50 0.99 5.05 0.34 0.40 2072.30 2071.70 2075.98 2.43 HDPE -
DI-106 I DI-105 I 0.20 I 100/0 I 90% I 0.84 I 8.15 I 1.3 I 3.7 I 0.012 I 0.02% 159.64I 25.5 I 15 I 0.7 I 0.91 I 4.10 I 1.00 I 1.00 I 0.74 I 1.68 I 1.74 I 2071.70 I 2071.69 I 2075.94 I 2.74 I HDPE I -
DI-105 3B-104 0.15 10% 90% 0.84 8.15 1.1 4.8 0.012 2.70% 55.28 10.8 15 9.4 11.52 0.41 0.45 0.94 8.82 1.78 1.84 2071.69 2070.20 2075.62 2.43 HDPE -
JB-104 I OWS I 0.00 I 0% I 100% I 0.90 I 8.15 I 0.0 I 4.8 I 0.010 I 0.00% I 20.68 I 10.8 I 16 I 0.0 I 0.00 I 0.00 I 0.00 I 0.00 I 0.00 I 0.00 I 0.00 I 2069.90 I 2069.90 I 2075.55 I 4.32 I DIP I -
OWS JB-103 0.00 0% 100% 0.90 8.15 0.0 4.8 0.010 0.00% 17.06 10.8 16 0.0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2069.90 2069.90 2076.12 4.89 DIP -
JB-103 3B-102 0.00 0% 100% 0.90 8.15 0.0 4.8 0.012 0.54% 74.15 14.6 18 4.7 8.38 0.57 0.50 0.99 4.69 0.26 0.26 2069.80 2069.40 2075.82 4.23 HDPE -
JB-102 I FES-101 I 0.00 I 0% I 100% I 0.90 I 8.15 I 0.0 I 4.8 I 0.012 I 2.01% 180.63 I 11.4 I 18 I 9.2 I 16.17 I 0.30 I 0.35 I 0.82 I 7.50 I 0.41 I 0.44 I 2069.20 I 2067.58 I 2072.00 I 1.01 I HDPE I -
xxx.xx Hold receiving pipe invert
Pipe invert higher than receiving
Drop in inverts

DUKE ENERGY 526 S Church Street
des DUKE Charlotte, NC 28202
ENERGY, Transmission Engineering
Rip-Rap Apron Summary Table
Minimum TW Condition
Discharge
Outlet Do (in) W1=Do + La W2=3*Do W2 H=(2/3)*Do
(cfs) d50 (ft) La (ft) W1 (ft) (ft) H (ft)
FES-101 I 4.8 I 18 I 0.5 I 10 I 11.50 I 4.50 I 1.125 I 1.00
DW CULVERT 2.0 15 0.5 10 11.25 3.75 1.125 0.83
dmax=1.5*d50
*T=1.5*dmax (Min. *T=10") Apron Thickness = *T
Min. La=10 ft
H=Depth of apron
min d50 = 0.5
Min Tailwater Condition (Figure 8.06a)
Max Tailwater Condition (Figure 8.06b)

W
Outlet W - Do + La
pipe 90 11:-- . ..
I
diameter (Do) I I IN f' �.
La _401 AO • IIm m= . r��
iliii _water t 0.5Do I Il:::"t'' •
C.- i III OI11I1 : -. .44
ve���r 1 L
.. . I ��� ` �� ODD'.' ..::
;/1 r
Itfiii'
i ^V fly. i �. / , • • I ,.,
.. - :-_ a ,. . . -.._i_ — —.4....... . ' iii
1
2
, • • • •—• ' it•
44
101 =g' - :. . :áj
.... :
Ar JI
ia�. •- iliorliiii, •...F.,,�.
,, 1 I ... .l . . 1 • • 0104;PI IIMIIIIN ea
• ,� ... III IIII■
Air.
.........00..4 • , 4 a 25 740410,9010flArr opr- . . . . ... ...
ii
..„' 3,00 . - A
101 . . . ..: ..: : , .„.. .
Lc,
, „,
iliiiii �.
v 5 •_..v,0"■n� . .. 101 =
�� l- _ 0.4
0
3 5 10 20 50 100 200 500 1000
101 = Discharge(ft3/sec)
4.8 cfs
Curves may not be extrapolated.
Figure 8.06a Design of outlet protection protection from a round pipe flowing full,minimum tailwater condition(T.<0.5 diameter)
Minimum's apply to both the FES-101 outfall and the
driveway culvert,due to the runoff of the contributing
drainage areas.
Rev.12 93 8.06.3

DUKE ENERGY 526 S Church Street
DUKE Charlotte,NC 28202
�' ENERGY. Transmission Engineering
ailirdigiailliMi
.III in 5574 Description
10/16/20 JAP Drop inlet analysis
Q JAP
Dro. Inlet Summa
MP Illr Standard DI Grate-NCDOT Type E
Orifice Condition &Weir Condition. Analysis Open Throat Inlet Calculations
Surface Q D=(Surface I H=(Surface
(cfs) Qtotal/(0.6)* D=[(Surface Qtotal/ DepthCondition Provided Freeboard Weir Lengt D=(Surface Q/ Is D>.5 Q/(0.6*.5*L* D=H+(.5/2) Depth of Flow
3.66sf* I3*i1Q8)JA2/3
(ft) L(ft) (3.3)(L))^2/3 (64.4^.5)))A (ft)
64.4^0.5)^2 (ft) 2
DI-108 I 0.8 0.002 I 0.08 I Weir I 0.60 I 0.52 N/A I #VALUE! I #VALUE! I #VALUE! I #VALUE! I #VALUE!
DI-107 1.5 0.008 0.12 Weir 0.60 0.48 N/A #VALUE! #VALUE! #VALUE! #VALUE! #VALUE!
DI-106 I 1.3 0.006 I 0.11 I Weir I 0.60 I 0.49 N/A I #VALUE! I #VALUE! I #VALUE! I #VALUE! I #VALUE!
DI-105 1.1 0.004 0.09 Weir 0.60 0.51 N/A #VALUE! #VALUE! #VALUE! #VALUE! #VALUE!

Ferncliff Ret
Station Number: 5574
Original Date: 10/16/20 DB: JAP
Revision Date: 2/16/23 PM: MTP
Open Channel Callout: D-1(AS-BUILT) *To match the plan sheet
Drainage Area: 88862.4 2.04 ac
Weighted Runoff Coefficient
Land Cover Description C-Value Area(ac) Percentage of Total Area Weighted C
Lawns 0.30 1.89 92.65% 0.28
GRAVEL IS CONSIDERED
Driveways/roofs/etc. 0.95 0.15 7.35% 0.07 PERVIOUS
Residential Development 0.60 0.00 0.00% 0.00
Total Drainage Area: 2.04 Weighted C-Value: 0.35
*Total drainage area must match the drainage are input above by the user
Estimated Runoff
Storm Event Rainfall Intensity-I(in/hr) Runoff(CFS)
10-Year/24-Hour 7.12 5.05
25-Year/24-Hour 8.15 5.78
50-Year/24-Hour 8.94 6.34
*Estimated runoff is calculated using the Rational Method and a Time of Concentration value of 5-min.
*Rainfall intensity values are provided by the NOAA Rainfall Data server and based on the specific site location
I Channel Parameters I
Top Elevation of Channel at start: 2069.61 ft
Bottom Elevation of Channel at end: 2062.88 ft
Length of Channel: 631 ft
Estimated Channel Slope: 0.011 ft/ft I
Permissible Velocities-Vp-Perm Grass Lining
Slope Vegetation Velocity(fps) *Design for low retardance(Class D)
0-5% Tall Fescue 4.50
i Lining Options Description Permissible Velocity(Vp)
Option 1 9"Stone 9.80 0.032
Option 2 6"stone 8.00 0.032
Option 3 Concrete 20.00 0.013
Option 4 Grass-Lined 4.50 0.030
Temp Lining 1 NAG SC150 8.00 0.022
Perm Lining 1 _ NAG ERONET P300 9.00 0.030
*values taken from tables and support information found on the Appendix tab

Ferncliff Ret
Station Number: 5574
Original Date: 10/16/20 JAP
Revision Date: 2/16/23 MTP
Bottom Width(B): 2.00 ft
Side Slopes(M:1) 4
Max Depth of Channel: 2.00 ft
Max.Allowed Velocity in Channel
Cross-Sectional Area 20.00 sf
Wetted Perimeter 18.49 ft
Hydraulic Radius 1.08 ft
Max Allowed Velocity ft/s
Best Hydraulic Section Method(Channel with good maintenance)
Cm= 0.595
k= 0.246
*Data taken from appendix tab
Cm[Qn/sgrt(S)]^(3/8)= y= 0.72 ft
8.67 in
Depth is Okay
*assumed grass lined channel for the 25-year/24-hour storm event with a Tc of 5-minutes

Ferncliff Ret
Station Number: 5574
Original Date: 10/16/20 JAP
Revision Date: 2/16/23 MTP
Normal-Depth Procedure(Channel with no maintenance)
MANNINGS N: 0.080 unmaintained channel/brushy
*conservative approach
Z10 required: 2.626
Z25 required: 3.006
Z50 required: 3.298
REMARKS
NORMAL DEPTH-y(ft) AREA-A(sf) WETTED PERIMETER-P(Fr) HYD RADIUS-R(ft) Z10 Comp I Z25 Comp I Z50 Comp
0.10 0.24 2.82 0.08 0.05 NARROW NARROW NARROW
0.15 0.39 3.24 0.12 0.10 NARROW NARROW NARROW
0.20 0.56 3.65 0.15 0.16 NARROW NARROW NARROW
0.25 0.75 4.06 0.18 0.24 NARROW NARROW NARROW
0.30 0.96 4.47 0.21 0.34 NARROW NARROW NARROW
0.35 1.19 4.89 0.24 0.46 NARROW NARROW NARROW
0.40 1.44 5.30 0.27 0.60 NARROW NARROW NARROW
0.45 1.71 5.71 0.30 0.77 NARROW NARROW NARROW
0.50 2.00 6.12 0.33 0.95 NARROW NARROW NARROW
0.55 2.31 6.54 0.35 1.15 NARROW NARROW NARROW
0.60 2.64 6.95 0.38 1.38 NARROW NARROW NARROW
0.65 2.99 7.36 0.41 1.64 NARROW NARROW NARROW
0.70 3.36 7.77 0.43 1.92 NARROW NARROW NARROW
0.75 3.75 8.18 0.46 2.23 NARROW NARROW NARROW
0.80 4.16 8.60 0.48 2.56 NARROW NARROW NARROW
0.85 4.59 9.01 0.51 2.93 WIDE NARROW NARROW
0.90 5.04 9.42 0.53 3.32 WIDE WIDE WIDE
0.95 5.51 9.83 0.56 3.74 WIDE WIDE WIDE
1.00 6.00 10.25 0.59 4.20 WIDE WIDE WIDE
1.05 6.51 10.66 0.61 4.69 WIDE WIDE WIDE
1.10 7.04 11.07 0.64 5.21 WIDE WIDE WIDE
1.15 7.59 11.48 0.66 5.76 WIDE WIDE WIDE
1.20 8.16 11.90 0.69 6.35 WIDE WIDE WIDE
1.25 8.75 12.31 0.71 6.97 WIDE WIDE WIDE
1.30 9.36 12.72 0.74 7.63 WIDE WIDE WIDE
1.35 9.99 13.13 0.76 8.32 WIDE WIDE WIDE
1.40 10.64 13.54 0.79 9.06 WIDE WIDE WIDE
1.45 11.31 13.96 0.81 9.83 WIDE WIDE WIDE
1.50 12.00 14.37 0.84 10.64 WIDE WIDE WIDE
1.55 12.71 14.78 0.86 11.49 WIDE WIDE WIDE
1.60 13.44 15.19 0.88 12.38 WIDE WIDE WIDE

Ferncliff Ret
Station Number: 5574
Original Date: 10/16/20 DB: JAP
Revision Date: 2/16/23 PM: MTP
1.65 14.19 15.61 0.91 13.32 WIDE WIDE WIDE
1.70 14.96 16.02 0.93 14.29 WIDE WIDE WIDE
1.75 15.75 16.43 0.96 15.31 WIDE WIDE WIDE
1.80 16.56 16.84 0.98 16.37 WIDE WIDE WIDE
*analyze the normal depth and the limited depth based on site grading limits
*designer to compare the best hydraulic section results and normal depth results provided to make an engineering judgement call.Shear calculations can be completed based on dimension and lining type.
Normal Depth Interpolation
Normal Depth-v(ft)
0.80 2.56
Ix *25-year storm
0.85 2.93
x= 0.86flMil.--1
10.32 i
Velocity Calculations based on Channel Dimensions
V=[1.49*RA(2/3)SA(1/2)]/n
Lining Options Description Calculated Velocity-V(fps) Velocity Check Q-actual(cfs)
Option 1 9"Stone 2.91 Velocity OK 13.63
Option 2 6"stone 2.91 Velocity OK 13.63
Option 3 Concrete 7.17 redesign 33.54
Option 4 Grass-Lined 3.11 Velocity OK 14.54
Temp Lining 1 NAG SC150 4.23 Velocity OK 19.82
Perm Lining 1 NAG ERONET P300 3.11 Velocity OK 14.54
Tractive Force Calculations
Shear Stress at Normal Depth
T=wds 0.573 lb/sf
w=unit weight of water 62.4 lb/cf
d=flow depth 0.86 ft
s=channel slope 0.011 ft/ft
Td=permissible shear stress(temp) 2.00 lb/sf Temp lining permissible shear stress
Lining OK NAGSC15O W/RIP-RAP CHECK DAMS
Td=permissible shear stress(perm) 3.00 lb/sf Perm lining permissable shear stress
Lining OK ERONET P300&TALL FESCUE

Ferncliff Ret
Station Number: 5574
Original Date: 10/16/20 DB: JAP
Revision Date: 2/16/23 PM: MTP
Open Channel Callout: D-2(AS-BUILT) ]*To match the plan sheet
Drainage Area: 45302.4 1.04 ac
Weighted Runoff Coefficient
Land Cover Description C-Value Area(ac) Percentage of Total Area Weighted C
Lawns 0.30 0.98 94.23% 0.28
Driveways/roofs/etc. 0.95 0.06 5.77% 0.05
Residential Development 0.60 0.00 0.00% 0.00
Total Drainage Area: 1.04 Weighted C-Value: 0.34
*Total drainage area must match the drainage are input above by the user
Estimated Runoff
Storm Event Rainfall Intensity-I(in/hr) Runoff(CFS)
10-Year/24-Hour 7.12 2.50
25-Year/24-Hour 8.15 2.86
50-Year/24-Hour 8.94 _ 3.14
*Estimated runoff is calculated using the Rational Method and a Time of Concentration value of 5-min.
*Rainfall intensity values are provided by the NOAA Rainfall Data server and based on the specific site location
Channel Parameters
Top Elevation of Channel at start: 2070.08 ft
Bottom Elevation of Channel at end: 2065.78 ft
Length of Channel: 303.54 ft
Estimated Channel Slope: 0.014 ft/ft I
Permissible Velocities-VD-Perm Grass Lining
Slope Vegetation Velocity(fps) *Design for low retardance(Class D)
0-5% Tall Fescue 4.50
II Lining Options Description Permissible Velocity(Vp) Manning n-Value:
Option 1 9"Stone 9.80 0.032
Option 2 6"stone 8.00 0.032
Option 3 Concrete 20.00 0.013
Option 4 Grass-Lined 4.50 0.030
Temp Lining 1 Straw Mat 5.00 0.028
Temp Lining 2 Straw/Coconut Mix 5.00 0.025
*values taken from tables and support information found on the Appendix tab

Ferncliff Ret
Station Number: 5574
Original Date: 10/16/20 DB: JAP
Revision Date: 2/16/23 PM: MTP
Bottom Width(B): 2.00 ft
Side Slopes(M:1) 4
Max Depth of Channel: 2.00 ft
Max.Allowed Velocity in Channel
Cross-Sectional Area 20.00 sf
Wetted Perimeter 20.00 ft
Hydraulic Radius 1.00 ft
Max Allowed Velocity 5.911 ft/s
Best Hydraulic Section Method(Channel with good maintenance)
Cm= 0.595
k= 0.246
*Data taken from appendix tab
Cm[Qn/sgrt(S)]A(3/8)= y= 0.53 ft I
Depth is Okay
*assumed grass lined channel for the 25-year/24-hour storm event with a Tc of 5-minutes

Ferncliff Ret
Station Number: 5574
Original Date: 10/16/20 DB: JAP
Revision Date: 2/16/23 PM: MTP
Normal-Depth Procedure(Channel with no maintenance)
MANNINGS N: 0.080 unmaintained channel/brushy
Z10 required: 1.127
Z25 required: 1.290
Z50 required: 1.416
REMARKS
NORMAL DEPTH-y(ft) AREA-A(sf) WETTED PERIMETER-P(FT) HYD RADIUS-R(ft) Zav Z10 Comp I Z25 Comp I Z50 Comp
0.10 0.24 2.82 0.08 0.05 NARROW NARROW NARROW
0.15 0.39 3.24 0.12 0.10 NARROW NARROW NARROW
0.20 0.56 3.65 0.15 0.16 NARROW NARROW NARROW
0.25 0.75 4.06 0.18 0.24 NARROW NARROW NARROW
0.30 0.96 4.47 0.21 0.34 NARROW NARROW NARROW
0.35 1.19 4.89 0.24 0.46 NARROW NARROW NARROW
0.40 1.44 5.30 0.27 0.60 NARROW NARROW NARROW
0.45 1.71 5.71 0.30 0.77 NARROW NARROW NARROW
0.50 2.00 6.12 0.33 0.95 NARROW NARROW NARROW
0.55 2.31 6.54 0.35 1.15 WIDE NARROW NARROW
0.60 2.64 6.95 0.38 1.38 WIDE WIDE NARROW
0.65 2.99 7.36 0.41 1.64 WIDE WIDE WIDE
0.70 3.36 7.77 0.43 1.92 WIDE WIDE WIDE
0.75 3.75 8.18 0.46 2.23 WIDE WIDE WIDE
0.80 4.16 8.60 0.48 2.56 WIDE WIDE WIDE
0.85 4.59 9.01 0.51 2.93 WIDE WIDE WIDE
0.90 5.04 9.42 0.53 3.32 WIDE WIDE WIDE
0.95 5.51 9.83 0.56 3.74 WIDE WIDE WIDE
1.00 6.00 10.25 0.59 4.20 WIDE WIDE WIDE
1.05 6.51 10.66 0.61 4.69 WIDE WIDE WIDE
1.10 7.04 11.07 0.64 5.21 WIDE WIDE WIDE
1.15 7.59 11.48 0.66 5.76 WIDE WIDE WIDE
1.20 8.16 11.90 0.69 6.35 WIDE WIDE WIDE
1.25 8.75 12.31 0.71 6.97 WIDE WIDE WIDE
1.30 9.36 12.72 0.74 7.63 WIDE WIDE WIDE
1.35 9.99 13.13 0.76 8.32 WIDE WIDE WIDE
1.40 10.64 13.54 0.79 9.06 WIDE WIDE WIDE
1.45 11.31 13.96 0.81 9.83 WIDE WIDE WIDE
1.50 12.00 14.37 0.84 10.64 WIDE WIDE WIDE
1.55 12.71 14.78 0.86 11.49 WIDE WIDE WIDE

Ferncliff Ret
Station Number: 5574
Original Date: 10/16/20 DB: JAP
Revision Date: 2/16/23 PM: MTP
1.60 13.44 15.19 0.88 12.38 WIDE WIDE WIDE
1.65 14.19 15.61 0.91 13.32 WIDE WIDE WIDE
1.70 14.96 16.02 0.93 14.29 WIDE WIDE WIDE
1.75 15.75 16.43 0.96 15.31 WIDE WIDE WIDE
1.80 16.56 16.84 0.98 16.37 WIDE WIDE WIDE
*analyze the normal depth and the limited depth based on site grading limits
*designer to compare the best hydraulic section results and normal depth results provided to make an engineering judgement call.Shear calculations can be completed based on dimension and lining type.
Normal Depth Interpolation
Normal Depth-y(ft) Zav -
0.55 1.15
x 1.290 *25-year storm
0.60 1.38
I x= 0.58 ft
6.97 in
Velocity Calculations based on Channel Dimensions
V=[1.49*R^(2/3)S^(1/2)]/n
Lining Options Description Calculated Velocity-V(fps) Velocity Check Q-actual(cfs)
Option 1 9"Stone 3.48 ✓elocity OK 5.85
Option 2 6"stone 3.48 Velocity OK 5.85
Option 3 Concrete 8.56 redesign 12.69
Option 4 Grass-Lined 3.71 Velocity OK 6.16
Temp Lining 1 Straw Mat 3.97 Velocity OK 6.52
Temp Lining 2 Straw/Coconut Mix 4.45 Velocity OK 7.16
Tractive Force Calculations
Shear Stress at Normal Depth
T=wds 0.513 lb/sf
w=unit weight of water 62.4 lb/cf
d=flow depth 0.58 ft
s=channel slope 0.014 ft/ft
Td=permissible shear stress(temp) 1.75 lb/sf Temp lining permissible shear stress
Lining OK Straw Mat
Td=permissible shear stress(perm) 1.50 lb/sf Perm lining permissable shear stress
Lining OK Grass-Lined

Ferncliff Ret
Station Number: 5574
Original Date: 10/16/20 DB: JAP
Revision Date: 2/16/23 PM: MTP
Open Channel Callout: D-3(FRONT SWALE)-AS-BUILT *To match the plan sheet
Drainage Area: 72745.2 I 1.67 ac
Weighted Runoff Coefficient
Land Cover Description C-Value Area(ac) Percentage of Total Area Weighted C
Lawns 0.30 1.35 80.90% 0.24
Driveways/roofs/etc. 0.95 0.32 19.10% 0.18
Residential Development 0.60 0.00 0.00% 0.00
Total Drainage Area: 1.67 Weighted C-Value: 0.42
*Total drainage area must match the drainage are input above by the user
Estimated Runoff
Storm Event Rainfall Intensity-I(in/hr) Runoff(CFS)
10-Year/24-Hour 7.12 5.04
25-Year/24-Hour 8.15 5.77
50-Year/24-Hour 8.94 _ 6.33
*Estimated runoff is calculated using the Rational Method and a Time of Concentration value of 5-min.
*Rainfall intensity values are provided by the NOAA Rainfall Data server and based on the specific site location
Channel Parameters
Top Elevation of Channel at start: 2070.90 ft
Bottom Elevation of Channel at end: 2062.00 ft
Length of Channel: 348.71 ft
Estimated Channel Slope: 0.026 ft/ft I
Permissible Velocities-VD-Perm Grass Lining
Slope Vegetation Velocity(fps) *Design for low retardance(Class D)
0-5% Tall Fescue 4.50
II Lining Options Description Permissible Velocity(Vp) Manning n-Value:
Option 1 9"Stone 9.80 0.032
Option 2 6"stone 8.00 0.032
Option 3 Concrete 20.00 0.013
Option 4 Grass-Lined 4.50 0.030
Temp Lining 1 Straw Mat 5.00 0.028
Temp Lining 2 Straw/Coconut Mix 5.00 0.025
*values taken from tables and support information found on the Appendix tab

Ferncliff Ret
Station Number: 5574
Original Date: 10/16/20 DB: JAP
Revision Date: 2/16/23 PM: MTP
Bottom Width(B): 2.00 ft
Side Slopes(M:1) 4
Max Depth of Channel: 2.00 ft
Max.Allowed Velocity in Channel
Cross-Sectional Area 20.00 sf
Wetted Perimeter 20.00 ft
Hydraulic Radius 1.00 ft
Max Allowed Velocity 7.935 ft/s
Best Hydraulic Section Method(Channel with good maintenance)
Cm= 0.595
k= 0.246
*Data taken from appendix tab
Cm[Qn/sgrt(S)]A(3/8)= y= 0.61 ft I
Depth is Okay
*assumed grass lined channel for the 25-year/24-hour storm event with a Tc of 5-minutes

Ferncliff Ret
Station Number: 5574
Original Date: 10/16/20 DB: JAP
Revision Date: 2/16/23 PM: MTP
Normal-Depth Procedure(Channel with no maintenance)
MANNINGS N: 0.080 unmaintained channel/brushy
Z10 required: 1.695
Z25 required: 1.940
Z50 required: 2.128
REMARKS
NORMAL DEPTH-y(ft) AREA-A(sf) WETTED PERIMETER-P(FT) HYD RADIUS-R(ft) Zav Z10 Comp I Z25 Comp I Z50 Comp
0.10 0.24 2.82 0.08 0.05 NARROW NARROW NARROW
0.15 0.39 3.24 0.12 0.10 NARROW NARROW NARROW
0.20 0.56 3.65 0.15 0.16 NARROW NARROW NARROW
0.25 0.75 4.06 0.18 0.24 NARROW NARROW NARROW
0.30 0.96 4.47 0.21 0.34 NARROW NARROW NARROW
0.35 1.19 4.89 0.24 0.46 NARROW NARROW NARROW
0.40 1.44 5.30 0.27 0.60 NARROW NARROW NARROW
0.45 1.71 5.71 0.30 0.77 NARROW NARROW NARROW
0.50 2.00 6.12 0.33 0.95 NARROW NARROW NARROW
0.55 2.31 6.54 0.35 1.15 NARROW NARROW NARROW
0.60 2.64 6.95 0.38 1.38 NARROW NARROW NARROW
0.65 2.99 7.36 0.41 1.64 NARROW NARROW NARROW
0.70 3.36 7.77 0.43 1.92 WIDE NARROW NARROW
0.75 3.75 8.18 0.46 2.23 WIDE WIDE WIDE
0.80 4.16 8.60 0.48 2.56 WIDE WIDE WIDE
0.85 4.59 9.01 0.51 2.93 WIDE WIDE WIDE
0.90 5.04 9.42 0.53 3.32 WIDE WIDE WIDE
0.95 5.51 9.83 0.56 3.74 WIDE WIDE WIDE
1.00 6.00 10.25 0.59 4.20 WIDE WIDE WIDE
1.05 6.51 10.66 0.61 4.69 WIDE WIDE WIDE
1.10 7.04 11.07 0.64 5.21 WIDE WIDE WIDE
1.15 7.59 11.48 0.66 5.76 WIDE WIDE WIDE
1.20 8.16 11.90 0.69 6.35 WIDE WIDE WIDE
1.25 8.75 12.31 0.71 6.97 WIDE WIDE WIDE
1.30 9.36 12.72 0.74 7.63 WIDE WIDE WIDE
1.35 9.99 13.13 0.76 8.32 WIDE WIDE WIDE
1.40 10.64 13.54 0.79 9.06 WIDE WIDE WIDE
1.45 11.31 13.96 0.81 9.83 WIDE WIDE WIDE
1.50 12.00 14.37 0.84 10.64 WIDE WIDE WIDE
1.55 12.71 14.78 0.86 11.49 WIDE WIDE WIDE

Ferncliff Ret
Station Number: 5574
Original Date: 10/16/20 DB: JAP
Revision Date: 2/16/23 PM: MTP
1.60 13.44 15.19 0.88 12.38 WIDE WIDE WIDE
1.65 14.19 15.61 0.91 13.32 WIDE WIDE WIDE
1.70 14.96 16.02 0.93 14.29 WIDE WIDE WIDE
1.75 15.75 16.43 0.96 15.31 WIDE WIDE WIDE
1.80 16.56 16.84 0.98 16.37 WIDE WIDE WIDE
*analyze the normal depth and the limited depth based on site grading limits
*designer to compare the best hydraulic section results and normal depth results provided to make an engineering judgement call.Shear calculations can be completed based on dimension and lining type.
Normal Depth Interpolation
Normal Depth-y(ft) Zav -
0.65 1.64
x 1.940 *25-year storm
0.70 1.92
I x= 0.70 ft
8.44 in
Velocity Calculations based on Channel Dimensions
V=[1.49*R^(2/3)S^(1/2)]/n
Lining Options Description Calculated Velocity-V(fps) Velocity Check
Option 1 9"Stone 4.17 ✓elocity OK
Option 2 6"stone 4.17 Velocity OK
Option 3 Concrete 10.26 redesign
Option 4 Grass-Lined 4.44 Velocity OK
Temp Lining 1 Straw Mat 4.76 Velocity OK
Temp Lining 2 Straw/Coconut Mix 5.33 redesign
Tractive Force Calculations
Shear Stress at Normal Depth
T=wds 1.121 lb/sf
w=unit weight of water 62.4 lb/cf
d=flow depth 0.70 ft
s=channel slope 0.026 ft/ft
Td=permissible shear stress(temp) 1.75 lb/sf Temp lining permissible shear stress
Lining OK Straw Mat
Td=permissible shear stress(perm) 1.50 lb/sf Perm lining permissable shear stress
Lining OK Grass-Lined

HEC-HMS Technical Reference Manual - CN Tables
The four pages in this section are reproduced from the SCS(now NRCS) report Urban hydrology for small
watersheds.This report is commonly known as TR-55.The tables provide estimates of the curve number(CN)as a
function of hydrologic soil group(HSG),cover type,treatment,hydrologic condition,antecedent runoff condition
(ARC),and impervious area in the catchment.
TR-55 provides the following guidance for use of these tables:
• Soils are classified into four HSG's(A,B,C,and D)according to their minimum infiltration rate,which is
obtained for bare soil after prolonged wetting.Appendix A\[of TR-55\]defines the four groups and provides
a list of most of the soils in the United States and their group classification.The soils in the area of interest
may be identified from a soil survey report,which can be obtained from local SCS offices or soil and water
conservation district offices.
• There are a number of methods for determining cover type.The most common are field reconnaissance,
aerial photographs,and land use maps.
• Treatment is a cover type modifier(used only in Table 2-2b)to describe the management of cultivated
agricultural lands. It includes mechanical practices,such as contouring and terracing,and management
practices,such as crop rotations and reduced or no tillage.
• Hydrologic condition indicates the effects of cover type and treatment on infiltration and runoff and is
generally estimated from density of plant and residue cover on sample areas.Good hydrologic condition
indicates that the soil usually has a low runoff potential for that specific hydrologic soil group,cover type
and treatment.Some factors to consider in estimating the effect of cover on infiltration and runoff are:(a)
canopy or density of lawns,crops,or other vegetative areas;(b)amount of year-round cover;(c)amount of
grass or close-seeded legumes in rotations;(d) percent of residue cover;and (e)degree of surface roughness.
• The index of runoff potential before a storm event is the antecedent runoff condition (ARC).The CN for the
average ARC at a site is the median value as taken from sample rainfall and runoff data.The curve numbers
in table 2-2 are for the average ARC,which is used primarily for design applications.
• The percentage of impervious area and the means of conveying runoff from impervious areas to the
drainage systems should be considered in computing CN for urban areas.An impervious area is considered
connected if runoff from it flows directly into the drainage systems. It is also considered connected if runoff
from it occurs as shallow concentrated shallow flow that runs over a pervious area and then into a drainage
system. Runoff from unconnected impervious areas is spread over a pervious area as sheet flow.
SCS TR-55 Table 2-2a-Runoff curve numbers for urban areas].
Cover description Curve numbers for
hydrologic soil group
Cover type and hydrologic condition Average percent A B C D
impervious area2
Fully developed urban areas
Open space(lawns,parks,golf courses,cemeteries,
etc.)3:
Poor condition (grass cover<50%) 68 79 86 89
Fair condition (grass cover 50%to 75%) 49 69 79 84
Good condition(grass cover>75%) 39 61 74 80
- 1

HEC-HMS Technical Reference Manual - CN Tables
Impervious areas:
Paved parking lots,roofs,driveways,etc. 98 - 98 98
(excluding right-of-way)
Streets and roads:
Paved;curbs and storm sewers(excluding 98 98 98 98
right-of-way)
Paved;open ditches(including right-of-way).... 83 89 92 93
Gravel(including right-of-way) 76 85 89 91
Dirt(including right-of-way) 72 82 87 89
Western desert urban areas:
Natural desert landscaping(pervious areas only)4.. 63 77 85 88
Artificial desert landscaping(impervious weed 96 96 96 96
barrier,desert shrub with 1-to 2-inch sand
or gravel mulch and basin borders)
Urban districts:
Commercial and business 85 89 92 94 95
Industrial 72 81 88 91 93
Residential districts by average lot size
1/8 acre or less(town houses) 65 77 85 90 92
1/4 acre 38 61 75 83 87
1/3 acre 30 57 72 81 86
1/2 acre 25 54 70 80 85
1 acre 20 51 68 79 84
- 2

HEC-HMS Technical Reference Manual - CN Tables
Row crops Straight row(SR) Poor 72 81 88 91
Good 67 - 85 89
SR+CR Poor 71 80 87 90
Good 64 75 82 85
Contoured (C) Poor 70 79 84 88
Good 65 75 82 86
C+CR Poor 69 78 83 87
Good 64 74 81 85
Contoured&terraced (C& Poor 66 74 80 82
T)
Good 62 71 78 81
C&T+CR Poor 65 73 79 81
Good 61 70 77 80
Small grain SR Poor 65 76 84 88
Good 63 75 83 87
SR+CR Poor 64 75 83 86
Good 60 72 80 84
C Poor 63 74 82 85
Good 61 73 81 84
C+CR Poor 62 73 81 84
Good 60 72 80 838
- 4

52
iri' DUKE DUKE ENERGY Cha6rlotte,NC 28202
ENERGY. Transmission Engineering
Station Name: Ferncliff Ret
Station Number: 5574
Original Date: 10/16/20 JAP
Revision Date: 2/16/23 JAP
As-built Impervious
Description As-built BUA Reserved BUA Total Max.Allow
(sf) (sf) BUA(sf)
station ABC access drive 22,983.74 0 22,984
*considered pervious station#57 stone 0 0 0
*considered pervious laydown&add itions/drive 0 0 0
EXISTING IMPERVIOUS TO REMAIN 0 0 0
Total Max.Lot BUA(SF) 22,984
Might-of-Way(R/W)allowable BUA Summary
Area(sf)
Parking/Sidewalks 0
Gravel Drive 0
Sidewalk 0
0
Total Max.BUA in R/W(sf) 0
Total Site Allowable BUA Summary
Total Proposed BUA(sf) 22,984
0.53 ac.
Proposed Subdivided Parcel Area(ac) 432891.02 9.94 ac.
Proposed Impervious% . 5.31%

Watershed Model Schematic Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020
to-1A PRE JA-1 B PRE JA-1 C PRE
c■ �A-2 PRE
o
4-COMBINED E
A-2 POST
■
6-Combined Sit re
DA-1 B POST
-FRONTVEG
0-VEGETATED SWALES
ilii.
5DA-1A POST
11 -DETENTIO AREA
UP
Legend
Hyd. Origin Description ■
13-COMBINED DA1 POST
1 SCS Runoff DA-1A PRE
2 SCS Runoff DA-1B PRE
3 SCS Runoff DA-1C PRE
4 Combine COMBINED DA1 PRE
5 SCS Runoff DA-2 PRE
6 Combine Combined Site-Pre ■
7 SCS Runoff DA-2 POST 14-Combined Site-Post
8 Reach FRONT VEG SWALE
9 SCS Runoff DA-1 B POST
10 Reach VEGETATED SWALES
11 Reservoir DETENTION AREA
12 SCS Runoff DA-1A POST
13 Combine COMBINED DA1 POST
14 Combine Combined Site-Post
Project: Ferncliff Ret_As-built.gpw Tuesday, 02/21 /2023

Hydrograph Return Period Recap Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020
Hyd. Hydrograph Inflow Peak Outflow(cfs) Hydrograph
No. type hyd(s) Description
(origin) 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr
1 SCS Runoff 44.23 97.41 131.40 221.29 DA-1A PRE
2 SCS Runoff 1.773 5.550 8.101 15.28 DA-1B PRE
3 SCS Runoff 1.882 5.890 8.598 16.22 DA-1C PRE
4 Combine 1,2,3 47.89 108.73 147.84 252.79 COMBINED DA1 PRE
5 SCS Runoff 2.291 6.878 9.955 18.54 DA-2 PRE
6 Combine 4, 5 49.90 115.39 157.79 271.30 Combined Site-Pre
7 SCS Runoff 3.730 8.843 12.09 21.10 DA-2 POST
8 Reach 7 3.704 8.833 12.09 21.07 FRONT VEG SWALE
9 SCS Runoff 4.293 12.34 17.69 32.59 DA-1B POST
10 Reach 9 3.670 11.30 16.50 31.00 VEGETATED SWALES
11 Reservoir 10 3.264 8.330 11.32 29.54 DETENTION AREA
12 SCS Runoff 42.45 95.42 129.45 220.17 DA-1A POST
13 Combine 11, 12 44.51 102.35 138.25 245.20 COMBINED DA1 POST
14 Combine 8, 13 48.21 111.19 150.35 265.98 Combined Site-Post
Proj. file: Ferncliff Ret_As-built.gpw Tuesday, 02/21 /2023

2-YR/24-HR Storm

Hydrograph Summary Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 44.23 2 720 102,233 DA-1A PRE
2 SCS Runoff 1.773 2 720 4,758 DA-1B PRE
3 SCS Runoff 1.882 2 720 5,050 DA-1C PRE
4 Combine 47.89 2 720 112,041 1,2,3 COMBINED DA1 PRE
5 SCS Runoff 2.291 2 718 5,092 DA-2 PRE
6 Combine 49.90 2 720 117,134 4,5 Combined Site-Pre
7 SCS Runoff 3.730 2 718 7,579 DA-2 POST
8 Reach 3.704 2 720 7,578 7 FRONT VEG SWALE
9 SCS Runoff 4.293 2 718 9,339 DA-1B POST
10 Reach 3.670 2 722 9,337 9 VEGETATEDSWALES
11 Reservoir 3.264 2 724 9,122 10 2063.95 1,007 DETENTION AREA
12 SCS Runoff 42.45 2 720 98,545 DA-1A POST
13 Combine 44.51 2 720 107,667 11, 12 COMBINED DA1 POST
14 Combine 48.21 2 720 115,244 8, 13 Combined Site-Post
Ferncliff Ret_As-built.gpw Return Period: 2 Year Tuesday, 02/21 /2023

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 1
DA-1A PRE
Hydrograph type = SCS Runoff Peak discharge = 44.23 cfs
Storm frequency = 2 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 102,233 cuft
Drainage area = 23.730 ac Curve number = 72*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 9.70 min
Total precip. = 3.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(9.000 x 61)+(14.730 x 78)]/23.730
DA-1A PRE
Q (cfs) Hyd. No. 1 -- 2 Year Q (cfs)
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 - J , 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 1 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 2
DA-1B PRE
Hydrograph type = SCS Runoff Peak discharge = 1.773 cfs
Storm frequency = 2 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 4,758 cuft
Drainage area = 2.120 ac Curve number = 61*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 8.60 min
Total precip. = 3.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(2.120 x 61)]/2.120
DA-1 B PRE
Q (cfs) Hyd. No. 2 -- 2 Year Q (cfs)
2.00 - 2.00
1.00 - 1.00
0.00 - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 2 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 3
DA-1C PRE
Hydrograph type = SCS Runoff Peak discharge = 1.882 cfs
Storm frequency = 2 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 5,050 cuft
Drainage area = 2.250 ac Curve number = 61*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 7.30 min
Total precip. = 3.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(2.250 x 61)]/2.250
DA-1 C PRE
Q (cfs) Hyd. No. 3 -- 2 Year Q (cfs)
2.00 - 2.00
1.00 - 1.00
0.00 - k 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 3 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 4
COMBINED DA1 PRE
Hydrograph type = Combine Peak discharge = 47.89 cfs
Storm frequency = 2 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 112,041 cuft
Inflow hyds. = 1, 2, 3 Contrib. drain. area = 28.100 ac
COMBINED DA1 PRE
Q (cfs) Hyd. No. 4 -- 2 Year Q (cfs)
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 4 — Hyd No. 1 Hyd No. 2 Hyd No. 3

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 5
DA-2 PRE
Hydrograph type = SCS Runoff Peak discharge = 2.291 cfs
Storm frequency = 2 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 5,092 cuft
Drainage area = 2.420 ac Curve number = 61
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 5.60 min
Total precip. = 3.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
DA-2 PRE
Q (cfs) Hyd. No. 5-- 2 Year Q (cfs)
3.00 3.00
2.00 2.00
1.00 - 1.00
0.00 - ' 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 5 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 6
Combined Site - Pre
Hydrograph type = Combine Peak discharge = 49.90 cfs
Storm frequency = 2 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 117,134 cuft
Inflow hyds. = 4, 5 Contrib. drain. area = 2.420 ac
Combined Site - Pre
Q (cfs) Hyd. No. 6 -- 2 Year Q (cfs)
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
JL*41"... ."-------- v
0.00 — — 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 6 Hyd No. 4 Hyd No. 5

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 7
DA-2 POST
Hydrograph type = SCS Runoff Peak discharge = 3.730 cfs
Storm frequency = 2 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 7,579 cuft
Drainage area = 2.320 ac Curve number = 68*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 3.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(0.420 x 98)+(1.900 x 61)]/2.320
DA-2 POST
Q (cfs) Hyd. No. 7 -- 2 Year Q (cfs)
4.00 4.00
3.00 3.00
2.00 2.00
1.00 1.00
0.00 - 1 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
— Hyd No. 7

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 8
FRONT VEG SWALE
Hydrograph type = Reach Peak discharge = 3.704 cfs
Storm frequency = 2 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 7,578 cuft
Inflow hyd. No. = 7 - DA-2 POST Section type = Trapezoidal
Reach length = 348.7 ft Channel slope = 2.0
Manning's n = 0.030 Bottom width = 2.0 ft
Side slope = 4.0:1 Max. depth = 2.0 ft
Rating curve x = 4.424 Rating curve m = 1.107
Ave. velocity = 4.35 ft/s Routing coeff. = 0.9064
Modified Att-Kin routing method used.
FRONT VEG SWALE
Q (cfs) Hyd. No. 8 -- 2 Year Q (cfs)
4.00 4.00
3.00 3.00
2.00 2.00
1.00 1.00
0.00 — - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
— Hyd No. 8 — Hyd No. 7

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 9
DA-1 B POST
Hydrograph type = SCS Runoff Peak discharge = 4.293 cfs
Storm frequency = 2 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 9,339 cuft
Drainage area = 4.140 ac Curve number = 62*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 3.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(0.060 x 98)+(4.080 x 61)]/4.140
DA-1 B POST
Q (cfs) Hyd. No. 9-- 2 Year Q(cfs)
5.00 5.00
4.00 4.00
3.00 3.00
2.00 2.00
1.00 1.00
0.00 - 1 - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 9 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 10
VEGETATED SWALES
Hydrograph type = Reach Peak discharge = 3.670 cfs
Storm frequency = 2 yrs Time to peak = 722 min
Time interval = 2 min Hyd. volume = 9,337 cuft
Inflow hyd. No. = 9 - DA-1 B POST Section type = Trapezoidal
Reach length = 662.5 ft Channel slope = 1.1
Manning's n = 0.030 Bottom width = 2.0 ft
Side slope = 4.0:1 Max. depth = 2.0 ft
Rating curve x = 3.281 Rating curve m = 1.107
Ave. velocity = 3.37 ft/s Routing coeff. = 0.5047
Modified Att-Kin routing method used.
VEGETATED SWALES
Q (cfs) Hyd. No. 10 -- 2 Year Q (cfs)
5.00 5.00
4.00 4.00
3.00 3.00
2.00 2.00
1.00 ` 1.00
0.00 1 — 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 10 Hyd No. 9

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 11
DETENTION AREA
Hydrograph type = Reservoir Peak discharge = 3.264 cfs
Storm frequency = 2 yrs Time to peak = 724 min
Time interval = 2 min Hyd. volume = 9,122 cuft
Inflow hyd. No. = 10 - VEGETATED SWALES Max. Elevation = 2063.95 ft
Reservoir name = DETENTION AREA Max. Storage = 1 ,007 cuft
Storage Indication method used.
DETENTION AREA
Q (cfs) Hyd. No. 11 -- 2 Year Q (cfs)
4.00 4.00
3.00 3.00
2.00 2.00
1.00 1.00
0.00 - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
— Hyd No. 11 — Hyd No. 10 MITI II Total storage used = 1,007 cuft

Pond Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Pond No. 1 - DETENTION AREA
Pond Data
Contours-User-defined contour areas.Conic method used for volume calculation.Begining Elevation=2063.00 ft
Stage/Storage Table
Stage(ft) Elevation(ft) Contour area(sqft) Incr.Storage(cuft) Total storage(cuft)
0.00 2063.00 205 0 0
1.00 2064.00 2,297 1,063 1,063
2.00 2065.00 6,361 4,160 5,222
3.00 2066.00 10,288 8,245 13,468
Culvert/Orifice Structures Weir Structures
[A] [B] [C] [PrfRsr] [A] [B] [C] [D]
Rise(in) = 18.00 18.00 0.00 0.00 Crest Len(ft) = 66.20 0.00 0.00 0.00
Span(in) = 18.00 18.00 0.00 0.00 Crest El.(ft) = 2065.00 0.00 0.00 0.00
No.Barrels = 1 1 0 0 Weir Coeff. = 2.60 3.33 3.33 3.33
Invert El.(ft) = 2063.20 2063.42 0.00 0.00 Weir Type = Broad --- --- ---
Length(ft) = 127.15 127.15 0.00 0.00 Multi-Stage = No No No No
Slope(%) = 0.21 0.57 0.00 n/a
N-Value = .013 .013 .013 n/a
Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 0.000(by Wet area)
Multi-Stage = n/a No No No TW Elev.(ft) = 0.00
Note:Culvert/Orifice outflows are analyzed under inlet(ic)and outlet(oc)control. Weir risers checked for orifice conditions(ic)and submergence(s).
Stage/Storage/Discharge Table
Stage Storage Elevation Clv A Clv B Clv C PrfRsr Wr A Wr B Wr C Wr D Exfil User Total
ft cuft ft cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs
0.00 0 2063.00 0.00 0.00 --- --- 0.00 --- 0.000
0.10 106 2063.10 0.00 0.00 --- --- 0.00 --- --- --- --- --- 0.000
0.20 213 2063.20 0.00 0.00 --- --- 0.00 --- --- --- --- --- 0.000
0.30 319 2063.30 0.04 oc 0.00 --- --- 0.00 --- --- 0.042
0.40 425 2063.40 0.17 oc 0.00 --- --- 0.00 --- --- --- --- --- 0.172
0.50 531 2063.50 0.38 oc 0.04 ic --- --- 0.00 --- --- --- --- --- 0.416
0.60 638 2063.60 0.65 oc 0.18 ic --- --- 0.00 --- 0.828
0.70 744 2063.70 0.97 oc 0.41 ic --- --- 0.00 --- --- --- 1.385
0.80 850 2063.80 1.32 oc 0.74 ic --- --- 0.00 --- --- --- --- --- 2.066
0.90 956 2063.90 1.70 oc 1.16 ic --- --- 0.00 --- --- --- 2.853
1.00 1,063 2064.00 2.08 oc 1.64 ic --- --- 0.00 --- --- --- --- 3.713
1.10 1,479 2064.10 2.46 oc 2.19 ic --- --- 0.00 --- --- --- --- --- 4.648
1.20 1,895 2064.20 2.83 oc 2.79 ic --- --- 0.00 --- --- --- --- --- 5.623
1.30 2,311 2064.30 3.17 oc 3.45 ic --- --- 0.00 --- --- --- --- --- 6.621
1.40 2,727 2064.40 3.48 oc 4.13 ic --- --- 0.00 --- --- --- --- --- 7.603
1.50 3,142 2064.50 3.72 oc 4.82 ic --- --- 0.00 --- --- --- --- --- 8.549
1.60 3,558 2064.60 3.88 oc 5.52 ic --- --- 0.00 --- 9.400
1.70 3,974 2064.70 3.77 oc 6.07 oc --- --- 0.00 --- --- --- --- --- 9.833
1.80 4,390 2064.80 4.42 oc 6.35 oc --- --- 0.00 --- --- --- --- --- 10.77
1.90 4,806 2064.90 4.98 oc 6.36 oc --- --- 0.00 --- --- --- --- --- 11.34
2.00 5,222 2065.00 5.48 oc 6.53 oc --- --- 0.00 --- --- --- --- --- 12.01
2.10 6,047 2065.10 5.94 oc 6.92 oc --- --- 5.45 --- --- --- --- --- 18.32
2.20 6,871 2065.20 6.37 oc 7.29 oc --- --- 15.39 --- --- --- --- --- 29.06
2.30 7,696 2065.30 6.78 oc 7.65 oc --- --- 28.29 --- --- --- --- --- 42.71
2.40 8,521 2065.40 7.16 oc 7.99 oc --- --- 43.53 --- --- --- --- --- 58.67
2.50 9,345 2065.50 7.52 oc 8.31 oc --- --- 60.85 --- --- --- --- --- 76.68
2.60 10,170 2065.60 7.86 oc 8.63 oc --- --- 80.21 --- --- --- --- --- 96.70
2.70 10,994 2065.70 8.19 oc 8.93 oc --- --- 101.00 --- --- --- --- --- 118.13
2.80 11,819 2065.80 8.51 oc 9.22 oc --- --- 123.40 --- --- --- --- --- 141.13
2.90 12,643 2065.90 8.82 oc 9.50 oc --- --- 147.17 --- --- --- --- --- 165.49
3.00 13,468 2066.00 9.11 oc 9.78 oc --- --- 172.12 --- --- --- --- --- 191.01

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 12
DA-1A POST
Hydrograph type = SCS Runoff Peak discharge = 42.45 cfs
Storm frequency = 2 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 98,545 cuft
Drainage area = 24.070 ac Curve number = 71*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 9.70 min
Total precip. = 3.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(9.290 x 61)+(14.730 x 78)+(0.050 x 98)]/24.070
DA-1 A POST
Q (cfs) Hyd. No. 12 -- 2 Year Q (cfs)
50.00 50.00
—L.....,
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 12 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 13
COMBINED DA1 POST
Hydrograph type = Combine Peak discharge = 44.51 cfs
Storm frequency = 2 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 107,667 cuft
Inflow hyds. = 11, 12 Contrib. drain. area = 24.070 ac
COMBINED DA1 POST
Q (cfs) Hyd. No. 13 -- 2 Year Q (cfs)
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
— Hyd No. 13 — Hyd No. 11 Hyd No. 12

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 14
Combined Site - Post
Hydrograph type = Combine Peak discharge = 48.21 cfs
Storm frequency = 2 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 115,244 cuft
Inflow hyds. = 8, 13 Contrib. drain. area = 0.000 ac
Combined Site - Post
Q (cfs) Hyd. No. 14 -- 2 Year Q (cfs)
50.00 50.00
40.00 40.00
30.00 30.00
20.00 1 20.00
10.00 10.00
0.00 l - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
— Hyd No. 14 — Hyd No. 8 Hyd No. 13

10-YR/24-H R Storm

Hydrograph Summary Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 97.41 2 718 223,068 DA-1A PRE
2 SCS Runoff 5.550 2 720 12,919 DA-1B PRE
3 SCS Runoff 5.890 2 720 13,711 DA-1C PRE
4 Combine 108.73 2 720 249,698 1,2,3 COMBINED DA1 PRE
5 SCS Runoff 6.878 2 718 13,825 DA-2 PRE
6 Combine 115.39 2 718 263,524 4,5 Combined Site-Pre
7 SCS Runoff 8.843 2 718 17,711 DA-2 POST
8 Reach 8.833 2 720 17,711 7 FRONT VEG SWALE
9 SCS Runoff 12.34 2 718 24,741 DA-1B POST
10 Reach 11.30 2 720 24,740 9 VEGETATEDSWALES
11 Reservoir 8.330 2 724 24,525 10 2064.48 3,046 DETENTION AREA
12 SCS Runoff 95.42 2 720 218,559 DA-1A POST
13 Combine 102.35 2 720 243,083 11, 12 COMBINED DA1 POST
14 Combine 111.19 2 720 260,794 8, 13 Combined Site-Post
Ferncliff Ret_As-built.gpw Return Period: 10 Year Tuesday, 02/21 /2023

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 1
DA-1A PRE
Hydrograph type = SCS Runoff Peak discharge = 97.41 cfs
Storm frequency = 10 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 223,068 cuft
Drainage area = 23.730 ac Curve number = 72*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 9.70 min
Total precip. = 5.50 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(9.000 x 61)+(14.730 x 78)]/23.730
DA-1A PRE
Q (cfs) Hyd. No. 1 -- 10 Year Q (cfs)
100.00 100.00
90.00 90.00
80.00 80.00
I
70.00 70.00
60.00 60.00
50.00 - 50.00
40.00 - 40.00
30.00 - 30.00
20.00 20.00
10.00 10.00
ol
0.00 - ` — 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 1 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 2
DA-1B PRE
Hydrograph type = SCS Runoff Peak discharge = 5.550 cfs
Storm frequency = 10 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 12,919 cuft
Drainage area = 2.120 ac Curve number = 61*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 8.60 min
Total precip. = 5.50 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(2.120 x 61)]/2.120
DA-1 B PRE
Q (cfs) Hyd. No. 2 -- 10 Year Q(cfs)
6.00 6.00
I
5.00 5.00
4.00 4.00
3.00 3.00
2.00 2.00
j ....,........H
1.00 1.00
0.00 - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 2 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 3
DA-1C PRE
Hydrograph type = SCS Runoff Peak discharge = 5.890 cfs
Storm frequency = 10 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 13,711 cuft
Drainage area = 2.250 ac Curve number = 61*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 7.30 min
Total precip. = 5.50 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(2.250 x 61)]/2.250
DA-1 C PRE
Q (cfs) Hyd. No. 3 -- 10 Year Q(cfs)
6.00 1 6.00
5.00 5.00
4.00 1 4.00
3.00 - 3.00
2.00 2.00
1.00 1.00
J _
0.00 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 3 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 4
COMBINED DA1 PRE
Hydrograph type = Combine Peak discharge = 108.73 cfs
Storm frequency = 10 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 249,698 cuft
Inflow hyds. = 1, 2, 3 Contrib. drain. area = 28.100 ac
COMBINED DA1 PRE
Q (cfs) Hyd. No. 4 -- 10 Year Q (cfs)
120.00 120.00
100.00 100.00
80.00 80.00
60.00 I 60.00
40.00 40.00
20.00 20.00
0.00 _ 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 4 Hyd No. 1 Hyd No. 2 Hyd No. 3

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 5
DA-2 PRE
Hydrograph type = SCS Runoff Peak discharge = 6.878 cfs
Storm frequency = 10 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 13,825 cuft
Drainage area = 2.420 ac Curve number = 61
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 5.60 min
Total precip. = 5.50 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
DA-2 PRE
Q (cfs) Hyd. No. 5-- 10 Year Q(cfs)
7.00 7.00
6.00 6.00
5.00 5.00
4.00 4.00
3.00 3.00
2.00 2.00
1.00 1.00
0.00 - . - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 5 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 6
Combined Site - Pre
Hydrograph type = Combine Peak discharge = 115.39 cfs
Storm frequency = 10 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 263,524 cuft
Inflow hyds. = 4, 5 Contrib. drain. area = 2.420 ac
Combined Site - Pre
Q (cfs) Hyd. No. 6 -- 10 Year Q (cfs)
120.00 120.00
100.00 100.00
80.00 80.00
60.00 60.00
40.00 40.00
20.00 20.00
0.00 — " — 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 6 Hyd No. 4 Hyd No. 5

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 7
DA-2 POST
Hydrograph type = SCS Runoff Peak discharge = 8.843 cfs
Storm frequency = 10 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 17,711 cuft
Drainage area = 2.320 ac Curve number = 68*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 5.50 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(0.420 x 98)+(1.900 x 61)]/2.320
DA-2 POST
Q (cfs) Hyd. No. 7 -- 10 Year Q (cfs)
10.00 - 10.00
8.00 8.00
l
6.00 6.00
4.00 - 4.00
2.00 2.00
0.00 - s '- 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 7 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 8
FRONT VEG SWALE
Hydrograph type = Reach Peak discharge = 8.833 cfs
Storm frequency = 10 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 17,711 cuft
Inflow hyd. No. = 7 - DA-2 POST Section type = Trapezoidal
Reach length = 348.7 ft Channel slope = 2.0
Manning's n = 0.030 Bottom width = 2.0 ft
Side slope = 4.0:1 Max. depth = 2.0 ft
Rating curve x = 4.424 Rating curve m = 1.107
Ave. velocity = 4.73 ft/s Routing coeff. = 0.9479
Modified Att-Kin routing method used.
FRONT VEG SWALE
Q (cfs) Hyd. No. 8 -- 10 Year Q (cfs)
10.00 - 10.00
8.00 8.00
6.00 - 6.00
4.00 - 4.00
2.00 2.00
0.00 - "*"4" -------- s - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 8 Hyd No. 7

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 9
DA-1 B POST
Hydrograph type = SCS Runoff Peak discharge = 12.34 cfs
Storm frequency = 10 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 24,741 cuft
Drainage area = 4.140 ac Curve number = 62*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 5.50 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(0.060 x 98)+(4.080 x 61)]/4.140
DA-1 B POST
Q (cfs) Hyd. No. 9-- 10 Year Q (cfs)
14.00 - 14.00
•
12.00 - 12.00
10.00 10.00
8.00 8.00
6.00 — 6.00
4.00 4.00
2.00 - L.- 2.00
0.00 s - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 9 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 10
VEGETATED SWALES
Hydrograph type = Reach Peak discharge = 11.30 cfs
Storm frequency = 10 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 24,740 cuft
Inflow hyd. No. = 9 - DA-1 B POST Section type = Trapezoidal
Reach length = 662.5 ft Channel slope = 1.1
Manning's n = 0.030 Bottom width = 2.0 ft
Side slope = 4.0:1 Max. depth = 2.0 ft
Rating curve x = 3.281 Rating curve m = 1.107
Ave. velocity = 3.73 ft/s Routing coeff. = 0.5442
Modified Att-Kin routing method used.
VEGETATED SWALES
Q (cfs) Hyd. No. 10 -- 10 Year Q (cfs)
14.00 - 14.00
12.00 - 12.00
10.00 10.00
8.00 8.00
6.00 — 6.00
4.00 4.00
2.00 - 2.00
0.00 - ► `— 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 10 Hyd No. 9

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 11
DETENTION AREA
Hydrograph type = Reservoir Peak discharge = 8.330 cfs
Storm frequency = 10 yrs Time to peak = 724 min
Time interval = 2 min Hyd. volume = 24,525 cuft
Inflow hyd. No. = 10 - VEGETATED SWALES Max. Elevation = 2064.48 ft
Reservoir name = DETENTION AREA Max. Storage = 3,046 cuft
Storage Indication method used.
DETENTION AREA
Q (cfs) Hyd. No. 11 -- 10 Year Q (cfs)
12.00 12.00
10.00 - 10.00
8.00 - 8.00
6.00 1 - - 6.00
4.00 4.00
2.00 2.00
0.00 - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 11 Hyd No. 10 111111111 Total storage used = 3,046 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 12
DA-1A POST
Hydrograph type = SCS Runoff Peak discharge = 95.42 cfs
Storm frequency = 10 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 218,559 cuft
Drainage area = 24.070 ac Curve number = 71*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 9.70 min
Total precip. = 5.50 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(9.290 x 61)+(14.730 x 78)+(0.050 x 98)]/24.070
DA-1 A POST
Q (cfs) Hyd. No. 12 -- 10 Year Q (cfs)
100.00 100.00
90.00 90.00
80.00 80.00
70.00 70.00
60.00 60.00
50.00 - 50.00
40.00 - 40.00
30.00 - 30.00
20.00 20.00
10.00 10.00
0.00 - — ` - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 12 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 13
COMBINED DA1 POST
Hydrograph type = Combine Peak discharge = 102.35 cfs
Storm frequency = 10 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 243,083 cuft
Inflow hyds. = 11, 12 Contrib. drain. area = 24.070 ac
COMBINED DA1 POST
Q (cfs) Hyd. No. 13 -- 10 Year Q (cfs)
120.00 120.00
100.00 100.00
80.00 80.00
60.00 60.00
40.00 •
40.00
20.00 20.00
0.00 _ _ 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 13 Hyd No. 11 Hyd No. 12

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 14
Combined Site - Post
Hydrograph type = Combine Peak discharge = 111.19 cfs
Storm frequency = 10 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 260,794 cuft
Inflow hyds. = 8, 13 Contrib. drain. area = 0.000 ac
Combined Site - Post
Q (cfs) Hyd. No. 14 -- 10 Year Q (cfs)
120.00 120.00
1
100.00 100.00
80.00 80.00
60.00 I 60.00
40.00 40.00
20.00 20.00
0.00 4� " - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 14 Hyd No. 8 Hyd No. 13

25-YR/24-H R Storm

Hydrograph Summary Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 131.40 2 718 300,686 DA-1A PRE
2 SCS Runoff 8.101 2 720 18,601 DA-1B PRE
3 SCS Runoff 8.598 2 720 19,742 DA-1C PRE
4 Combine 147.84 2 718 339,029 1,2,3 COMBINED DA1 PRE
5 SCS Runoff 9.955 2 718 19,907 DA-2 PRE
6 Combine 157.79 2 718 358,936 4,5 Combined Site-Pre
7 SCS Runoff 12.09 2 718 24,393 DA-2 POST
8 Reach 12.09 2 720 24,393 7 FRONT VEG SWALE
9 SCS Runoff 17.69 2 718 35,374 DA-1B POST
10 Reach 16.50 2 720 35,373 9 VEGETATEDSWALES
11 Reservoir 11.32 2 724 35,158 10 2064.90 4,797 DETENTION AREA
12 SCS Runoff 129.45 2 718 296,137 DA-1A POST
13 Combine 138.25 2 720 331,294 11, 12 COMBINED DA1 POST
14 Combine 150.35 2 720 355,687 8, 13 Combined Site-Post
Ferncliff Ret_As-built.gpw Return Period: 25 Year Tuesday, 02/21 /2023

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 1
DA-1A PRE
Hydrograph type = SCS Runoff Peak discharge = 131.40 cfs
Storm frequency = 25 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 300,686 cuft
Drainage area = 23.730 ac Curve number = 72*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 9.70 min
Total precip. = 6.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(9.000 x 61)+(14.730 x 78)]/23.730
DA-1A PRE
Q (cfs) Hyd. No. 1 -- 25 Year Q (cfs)
140.00 140.00
120.00 120.00
100.00 — 100.00
80.00 1— 80.00
60.00 60.00
40.00 40.00
20.00 20.00
.1411:---
0.00 J `---- 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 1 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 2
DA-1B PRE
Hydrograph type = SCS Runoff Peak discharge = 8.101 cfs
Storm frequency = 25 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 18,601 cuft
Drainage area = 2.120 ac Curve number = 61*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 8.60 min
Total precip. = 6.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(2.120 x 61)]/2.120
DA-1 B PRE
Q (cfs) Hyd. No. 2 -- 25 Year Q (cfs)
10.00 - 10.00
8.00 8.00
6.00 6.00
4.00 - 4.00
2.00 2.00
0.00 - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 2 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 3
DA-1C PRE
Hydrograph type = SCS Runoff Peak discharge = 8.598 cfs
Storm frequency = 25 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 19,742 cuft
Drainage area = 2.250 ac Curve number = 61*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 7.30 min
Total precip. = 6.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(2.250 x 61)]/2.250
DA-1 C PRE
Q (cfs) Hyd. No. 3 -- 25 Year Q (cfs)
10.00 - 10.00
8.00 8.00
6.00 - 6.00
4.00 - 4.00
2.00 2.00
0.00 - J N 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 3 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 4
COMBINED DA1 PRE
Hydrograph type = Combine Peak discharge = 147.84 cfs
Storm frequency = 25 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 339,029 cuft
Inflow hyds. = 1, 2, 3 Contrib. drain. area = 28.100 ac
COMBINED DA1 PRE
Q (cfs) Hyd. No. 4 -- 25 Year Q (cfs)
160.00 160.00
140.00 140.00
120.00 120.00
100.00 100.00
80.00 80.00
1
60.00 60.00
40.00 40.00
20.00 20.00
0.00 —dark_ 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 4 Hyd No. 1 Hyd No. 2 Hyd No. 3

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 5
DA-2 PRE
Hydrograph type = SCS Runoff Peak discharge = 9.955 cfs
Storm frequency = 25 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 19,907 cuft
Drainage area = 2.420 ac Curve number = 61
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 5.60 min
Total precip. = 6.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
DA-2 PRE
Q (cfs) Hyd. No. 5-- 25 Year Q (cfs)
10.00 - 10.00
8.00 8.00
6.00 I - 6.00
4.00 - 4.00
2.00 :::
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 5 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 6
Combined Site - Pre
Hydrograph type = Combine Peak discharge = 157.79 cfs
Storm frequency = 25 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 358,936 cuft
Inflow hyds. = 4, 5 Contrib. drain. area = 2.420 ac
Combined Site - Pre
Q (cfs) Hyd. No. 6 -- 25 Year Q (cfs)
160.00 160.00
140.00 140.00
120.00 120.00
100.00 100.00
80.00 80.00
60.00 60.00
40.00 40.00
20.00 20.00
0.00 - - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 6 Hyd No. 4 Hyd No. 5

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 7
DA-2 POST
Hydrograph type = SCS Runoff Peak discharge = 12.09 cfs
Storm frequency = 25 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 24,393 cuft
Drainage area = 2.320 ac Curve number = 68*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 6.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(0.420 x 98)+(1.900 x 61)]/2.320
DA-2 POST
Q (cfs) Hyd. No. 7 -- 25 Year Q (cfs)
14.00 - 14.00
12.00 - 12.00
10.00 10.00
8.00 8.00
6.00 — 6.00
4.00 4.00
2.00 - 2.00
0.00 - " - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 7 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 8
FRONT VEG SWALE
Hydrograph type = Reach Peak discharge = 12.09 cfs
Storm frequency = 25 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 24,393 cuft
Inflow hyd. No. = 7 - DA-2 POST Section type = Trapezoidal
Reach length = 348.7 ft Channel slope = 2.0
Manning's n = 0.030 Bottom width = 2.0 ft
Side slope = 4.0:1 Max. depth = 2.0 ft
Rating curve x = 4.424 Rating curve m = 1.107
Ave. velocity = 4.88 ft/s Routing coeff. = 0.9630
Modified Att-Kin routing method used.
FRONT VEG SWALE
Q (cfs) Hyd. No. 8 -- 25 Year Q (cfs)
14.00 - 14.00
12.00 - 12.00
10.00 10.00
8.00 8.00
6.00 — 6.00
4.00 4.00
2.00 - 2.00
0.00 - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 8 Hyd No. 7

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 9
DA-1 B POST
Hydrograph type = SCS Runoff Peak discharge = 17.69 cfs
Storm frequency = 25 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 35,374 cuft
Drainage area = 4.140 ac Curve number = 62*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 6.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(0.060 x 98)+(4.080 x 61)]/4.140
DA-1 B POST
Q (cfs) Hyd. No. 9-- 25 Year Q (cfs)
18.00 - - - 1 18.00
15.00 15.00
12.00 12.00
9.00 9.00
6.00 6.00
-L....
3.00 3.00
0.00 1 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 9 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 10
VEGETATED SWALES
Hydrograph type = Reach Peak discharge = 16.50 cfs
Storm frequency = 25 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 35,373 cuft
Inflow hyd. No. = 9 - DA-1 B POST Section type = Trapezoidal
Reach length = 662.5 ft Channel slope = 1.1
Manning's n = 0.030 Bottom width = 2.0 ft
Side slope = 4.0:1 Max. depth = 2.0 ft
Rating curve x = 3.281 Rating curve m = 1.107
Ave. velocity = 3.86 ft/s Routing coeff. = 0.5581
Modified Att-Kin routing method used.
VEGETATED SWALES
Q (cfs) Hyd. No. 10 --25 Year Q (cfs)
18.00 18.00
15.00 15.00
12.00 12.00
9.00 9.00
6.00 6.00
3.00 3.00
0.00 - s — 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 10 Hyd No. 9

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 11
DETENTION AREA
Hydrograph type = Reservoir Peak discharge = 11.32 cfs
Storm frequency = 25 yrs Time to peak = 724 min
Time interval = 2 min Hyd. volume = 35,158 cuft
Inflow hyd. No. = 10 - VEGETATED SWALES Max. Elevation = 2064.90 ft
Reservoir name = DETENTION AREA Max. Storage = 4,797 cuft
Storage Indication method used.
DETENTION AREA
Q (cfs) Hyd. No. 11 --25 Year Q (cfs)
18.00 18.00
15.00 15.00
12.00 12.00
9.00 9.00
6.00 6.00
JL _
3.00 3.00
0.00 II. -- 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 11 Hyd No. 10 111111111 Total storage used = 4,797 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 12
DA-1A POST
Hydrograph type = SCS Runoff Peak discharge = 129.45 cfs
Storm frequency = 25 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 296,137 cuft
Drainage area = 24.070 ac Curve number = 71*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 9.70 min
Total precip. = 6.60 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(9.290 x 61)+(14.730 x 78)+(0.050 x 98)]/24.070
DA-1 A POST
Q (cfs) Hyd. No. 12 --25 Year Q (cfs)
140.00 140.00
120.00 120.00
100.00 1 100.00
80.00 80.00
60.00 60.00
40.00 40.00
20.00 20.00
0.00 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 12 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 13
COMBINED DA1 POST
Hydrograph type = Combine Peak discharge = 138.25 cfs
Storm frequency = 25 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 331,294 cuft
Inflow hyds. = 11, 12 Contrib. drain. area = 24.070 ac
COMBINED DA1 POST
Q (cfs) Hyd. No. 13 --25 Year Q (cfs)
140.00 140.00
120.00 120.00
100.00 100.00
80.00 � 80.00
60.00 60.00
40.00 40.00
20.00 20.00
0.00 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 13 Hyd No. 11 Hyd No. 12

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 14
Combined Site - Post
Hydrograph type = Combine Peak discharge = 150.35 cfs
Storm frequency = 25 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 355,687 cuft
Inflow hyds. = 8, 13 Contrib. drain. area = 0.000 ac
Combined Site - Post
Q (cfs) Hyd. No. 14 --25 Year Q (cfs)
160.00 160.00
140.00 140.00
120.00 120.00
100.00 100.00
80.00 80.00
60.00 60.00
40.00 40.00
20.00 20.00
0.00 ~� - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 14 Hyd No. 8 Hyd No. 13

100-YR/24-H R Storm

Hydrograph Summary Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 221.29 2 718 511,855 DA-1A PRE
2 SCS Runoff 15.28 2 718 34,969 DA-1B PRE
3 SCS Runoff 16.22 2 718 37,113 DA-1C PRE
4 Combine 252.79 2 718 583,937 1,2,3 COMBINED DA1 PRE
5 SCS Runoff 18.54 2 716 37,423 DA-2 PRE
6 Combine 271.30 2 718 621,360 4,5 Combined Site-Pre
7 SCS Runoff 21.10 2 716 42,912 DA-2 POST
8 Reach 21.07 2 718 42,912 7 FRONT VEG SWALE
9 SCS Runoff 32.59 2 716 65,816 DA-1B POST
10 Reach 31.00 2 720 65,815 9 VEGETATEDSWALES
11 Reservoir 29.54 2 722 65,600 10 2065.20 6,901 DETENTION AREA
12 SCS Runoff 220.17 2 718 508,132 DA-1A POST
13 Combine 245.20 2 720 573,732 11, 12 COMBINED DA1 POST
14 Combine 265.98 2 720 616,643 8, 13 Combined Site-Post
Ferncliff Ret_As-built.gpw Return Period: 100 Year Tuesday, 02/21 /2023

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 1
DA-1A PRE
Hydrograph type = SCS Runoff Peak discharge = 221.29 cfs
Storm frequency = 100 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 511,855 cuft
Drainage area = 23.730 ac Curve number = 72*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 9.70 min
Total precip. = 9.40 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(9.000 x 61)+(14.730 x 78)]/23.730
DA-1A PRE
Q (cfs) Hyd. No. 1 -- 100 Year Q (cfs)
240.00 240.00
210.00 210.00
180.00 180.00
150.00 - 150.00
—
I
120.00 120.00
90.00 90.00
60.00 IL 60.00
30.00 30.00
I
0.00 - - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 1 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 2
DA-1B PRE
Hydrograph type = SCS Runoff Peak discharge = 15.28 cfs
Storm frequency = 100 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 34,969 cuft
Drainage area = 2.120 ac Curve number = 61*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 8.60 min
Total precip. = 9.40 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(2.120 x 61)]/2.120
DA-1 B PRE
Q (cfs) Hyd. No. 2 -- 100 Year Q (cfs)
18.00 - - - 18.00
15.00 15.00
12.00 ' 12.00
9.00 9.00
6.00 6.00
3.00 3.00
0.00 - - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 2 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 3
DA-1C PRE
Hydrograph type = SCS Runoff Peak discharge = 16.22 cfs
Storm frequency = 100 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 37,113 cuft
Drainage area = 2.250 ac Curve number = 61*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 7.30 min
Total precip. = 9.40 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(2.250 x 61)]/2.250
DA-1 C PRE
Q (cfs) Hyd. No. 3 -- 100 Year Q (cfs)
18.00 18.00
15.00 15.00
12.00 12.00
9.00 9.00
6.00 6.00
3.00 3.00
01 —L------*
0.00 - - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 3 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 4
COMBINED DA1 PRE
Hydrograph type = Combine Peak discharge = 252.79 cfs
Storm frequency = 100 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 583,937 cuft
Inflow hyds. = 1, 2, 3 Contrib. drain. area = 28.100 ac
COMBINED DA1 PRE
Q (cfs) Hyd. No. 4 -- 100 Year Q (cfs)
280.00 280.00
1
240.00 240.00
200.00 200.00
160.00 160.00
120.00 120.00
80.00 80.00
40.00 40.00
AL111.1.1
0.00 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 4 Hyd No. 1 Hyd No. 2 Hyd No. 3

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 5
DA-2 PRE
Hydrograph type = SCS Runoff Peak discharge = 18.54 cfs
Storm frequency = 100 yrs Time to peak = 716 min
Time interval = 2 min Hyd. volume = 37,423 cuft
Drainage area = 2.420 ac Curve number = 61
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 5.60 min
Total precip. = 9.40 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
DA-2 PRE
Q (cfs) Hyd. No. 5 -- 100 Year Q (cfs)
21.00 21.00
18.00 18.00
15.00 15.00
12.00 I 12.00
9.00 9.00
6.00 6.00
3.00 3.00
N.144"..
0.00 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 5 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 6
Combined Site - Pre
Hydrograph type = Combine Peak discharge = 271.30 cfs
Storm frequency = 100 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 621,360 cuft
Inflow hyds. = 4, 5 Contrib. drain. area = 2.420 ac
Combined Site - Pre
Q (cfs) Hyd. No. 6 -- 100 Year Q (cfs)
280.00 280.00
240.00 240.00
200.00 200.00
160.00 160.00
120.00 120.00
80.00 80.00
40.00 40.00
0.00 - -� - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 6 Hyd No. 4 Hyd No. 5

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 7
DA-2 POST
Hydrograph type = SCS Runoff Peak discharge = 21.10 cfs
Storm frequency = 100 yrs Time to peak = 716 min
Time interval = 2 min Hyd. volume = 42,912 cuft
Drainage area = 2.320 ac Curve number = 68*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 9.40 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(0.420 x 98)+(1.900 x 61)]/2.320
DA-2 POST
Q (cfs) Hyd. No. 7 -- 100 Year Q (cfs)
24.00 24.00
20.00 20.00
16.00 16.00
12.00 12.00
8.00 8.00
4.00 4.00
0.00 — ' 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440
Hyd No. 7 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 8
FRONT VEG SWALE
Hydrograph type = Reach Peak discharge = 21.07 cfs
Storm frequency = 100 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 42,912 cuft
Inflow hyd. No. = 7 - DA-2 POST Section type = Trapezoidal
Reach length = 348.7 ft Channel slope = 2.0
Manning's n = 0.030 Bottom width = 2.0 ft
Side slope = 4.0:1 Max. depth = 2.0 ft
Rating curve x = 4.424 Rating curve m = 1.107
Ave. velocity = 5.14 ft/s Routing coeff. = 0.9899
Modified Att-Kin routing method used.
FRONT VEG SWALE
Q (cfs) Hyd. No. 8 -- 100 Year Q (cfs)
24.00 24.00
20.00 20.00
16.00 16.00
12.00 12.00
8.00 8.00
4.00 4.00
J
0.00 — 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440
Time (min)
Hyd No. 8 Hyd No. 7

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 9
DA-1 B POST
Hydrograph type = SCS Runoff Peak discharge = 32.59 cfs
Storm frequency = 100 yrs Time to peak = 716 min
Time interval = 2 min Hyd. volume = 65,816 cuft
Drainage area = 4.140 ac Curve number = 62*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 9.40 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(0.060 x 98)+(4.080 x 61)]/4.140
DA-1 B POST
Q (cfs) Hyd. No. 9 -- 100 Year Q (cfs)
35.00 35.00
30.00 30.00
25.00 25.00
I
20.00 20.00
15.00 15.00
10.00 10.00
5.00 5.00
0.00 - 1 — 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 9 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 10
VEGETATED SWALES
Hydrograph type = Reach Peak discharge = 31.00 cfs
Storm frequency = 100 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 65,815 cuft
Inflow hyd. No. = 9 - DA-1 B POST Section type = Trapezoidal
Reach length = 662.5 ft Channel slope = 1.1
Manning's n = 0.030 Bottom width = 2.0 ft
Side slope = 4.0:1 Max. depth = 2.0 ft
Rating curve x = 3.281 Rating curve m = 1.107
Ave. velocity = 4.10 ft/s Routing coeff. = 0.5822
Modified Att-Kin routing method used.
VEGETATED SWALES
Q (cfs) Hyd. No. 10 -- 100 Year Q (cfs)
35.00 35.00
30.00 30.00
25.00 25.00
20.00 20.00
15.00 15.00
10.00 - 10.00
5.00 5.00
0.00 L.- s 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 10 Hyd No. 9

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 11
DETENTION AREA
Hydrograph type = Reservoir Peak discharge = 29.54 cfs
Storm frequency = 100 yrs Time to peak = 722 min
Time interval = 2 min Hyd. volume = 65,600 cuft
Inflow hyd. No. = 10 - VEGETATED SWALES Max. Elevation = 2065.20 ft
Reservoir name = DETENTION AREA Max. Storage = 6,901 cuft
Storage Indication method used.
DETENTION AREA
Q (cfs) Hyd. No. 11 -- 100 Year Q (cfs)
35.00 35.00
30.00 30.00
25.00 ---- 25.00
20.00 20.00
15.00 15.00
10.00 1 10.00
5.00 II 5.00
IL
M i&
1�
0.00 ^ 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 11 Hyd No. 10 111111111 Total storage used = 6,901 cuft

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 12
DA-1A POST
Hydrograph type = SCS Runoff Peak discharge = 220.17 cfs
Storm frequency = 100 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 508,132 cuft
Drainage area = 24.070 ac Curve number = 71*
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 9.70 min
Total precip. = 9.40 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
*Composite(Area/CN)=[(9.290 x 61)+(14.730 x 78)+(0.050 x 98)]/24.070
DA-1 A POST
Q (cfs) Hyd. No. 12 -- 100 Year Q (cfs)
240.00 240.00
210.00 210.00
180.00 180.00
150.00 150.00
120.00 120.00
90.00 90.00
60.00 60.00
30.00 I 30.00
0.00 - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 12 Time (min)

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 13
COMBINED DA1 POST
Hydrograph type = Combine Peak discharge = 245.20 cfs
Storm frequency = 100 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 573,732 cuft
Inflow hyds. = 11, 12 Contrib. drain. area = 24.070 ac
COMBINED DA1 POST
Q (cfs) Hyd. No. 13 -- 100 Year Q (cfs)
280.00 280.00
240.00 240.00
200.00 200.00
_1_
160.00 160.00
120.00 120.00
80.00 80.00
40.00 40.00
0.00 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 13 Hyd No. 11 Hyd No. 12

Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Hyd. No. 14
Combined Site - Post
Hydrograph type = Combine Peak discharge = 265.98 cfs
Storm frequency = 100 yrs Time to peak = 720 min
Time interval = 2 min Hyd. volume = 616,643 cuft
Inflow hyds. = 8, 13 Contrib. drain. area = 0.000 ac
Combined Site - Post
Q (cfs) Hyd. No. 14 -- 100 Year Q (cfs)
280.00 280.00
240.00 240.00
200.00 200.00
160.00 160.00
120.00 120.00
80.00 80.00
40.00 40.00
- /1
0.00 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 14 Hyd No. 8 Hyd No. 13

Hydraflow Rainfall Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2020 Tuesday,02/21 /2023
Return Intensity-Duration-Frequency Equation Coefficients(FHA)
Period
(Yrs) B D E (N/A)
1 57.1398 12.2000 0.8752
2 73.8799 13.2000 0.8898
3 0.0000 0.0000 0.0000
5 75.3430 13.1000 0.8444
10 71.9699 12.4000 0.8031
25 64.5878 11.2000 0.7434
50 58.7767 10.2000 0.6975
100 52.9958 9.0000 0.6521
File name:Anderson SC IDF.IDF
Intensity= B/(Tc+ D)^E
Return Intensity Values(in/hr)
Period
(Yrs) 5 min 10 15 20 25 30 35 40 45 50 55 60
1 4.74 3.79 3.17 2.74 2.41 2.16 1.96 1.79 1.66 1.54 1.44 1.35
2 5.59 4.50 3.79 3.27 2.89 2.59 2.35 2.15 1.99 1.85 1.73 1.62
3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
5 6.53 5.32 4.51 3.92 3.48 3.14 2.86 2.63 2.44 2.28 2.13 2.01
10 7.26 5.93 5.04 4.41 3.93 3.55 3.25 2.99 2.78 2.60 2.45 2.31
25 8.15 6.67 5.70 5.00 4.48 4.07 3.74 3.46 3.23 3.03 2.86 2.71
50 8.81 7.22 6.19 5.46 4.90 4.47 4.12 3.83 3.58 3.37 3.19 3.03
100 9.48 7.77 6.67 5.90 5.31 4.86 4.49 4.19 3.93 3.71 3.52 3.35
1
Tc=time in minutes.Values may exceed 60.
'recip.file name:\\etfs0l\SubSite\Anderson Tie_W170199\CALCULATIONS\Routing Calculations\Anderson Precip.pcp
Rainfall Precipitation Table (in)
Storm
Distribution 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr
SCS 24-hour 2.97 3.60 0.00 4.42 5.50 6.60 7.66 9.40
SCS 6-Hr 2.15 2.56 0.00 3.17 3.68 4.45 5.12 5.88
Huff-1st 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Huff-2nd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Huff-3rd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Huff-4th 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Huff-Indy 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Custom 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00