SWA000083_Ferncliff Ret_Engineer's Report_Sealed 2020.11.23_Optimized_20201208

Stormwater & Erosion Control
Engineer’s Report

Project Name
Ferncliff Retail (New Substation)
Location
Town of Mills River, Henderson County, NC

Owner
Duke Energy Corp
PO Box 1007
Charlotte, NC 28201

Engineering Firm
Duke Energy Carolinas, LLC
526 S. Church Street
Charlotte, NC 28202

Engineer’s Contact Information
Contact: Joshua A. Peeler, PE
NC No: 047381
[e-mail]
[phone]

Date: October 16, 2020
Revised: November 23, 2020

DEC Project No: W170199
Bookmark Summary
Cover Sheet
Table of Contents
Narrative
Support Documentation
Storm Drainage - Conveyance Design
Impervious Calculation
Storm Drainage System Design
Open Channel Calculations D-1
Open Channel Calculations - D-2
Erosion Control Design
Skimmer Basin SK-1
Skimmer Basin SK-2
Skimmer Basin SK-3
Skimmer Basin SK-4
Manufacturing Specifications
11/23/2020

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 gravel substation pad. The substation pad and access drive will be
counted as impervious land cover. The Built-Upon Area (BUA) is calculated based on the
subdivided 9.94 acre parcel and is approximately 23% 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.

Engineering Design
Supporting Documentation
United States
Department of
Agriculture
A product of the National
Cooperative Soil Survey,
a joint effort of the United
States Department of
Agriculture and other
Federal agencies, State
agencies including the
Agricultural Experiment
Stations, and local
participants
Custom Soil Resource
Report for
Henderson County,
North CarolinaNatural
Resources
Conservation
Service
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.nrcs.usda.gov/wps/portal/nrcs/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 [phone] (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
scientists classified and named the soils in the survey area, they compared the
individual soils with similar soils in the same taxonomic class in other areas so that
they could confirm data and assemble additional data based on experience and
research.
The objective of soil mapping is not to delineate pure map unit components; the
objective is to separate the landscape into landforms or landform segments that
have similar use and management requirements. Each map unit is defined by a
unique combination of soil components and/or miscellaneous areas in predictable
proportions. Some components may be highly contrasting to the other components
of the map unit. The presence of minor components in a map unit in no way
diminishes the usefulness or accuracy of the data. The delineation of such
landforms and landform segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, onsite
investigation is needed to define and locate the soils and miscellaneous areas.
Soil scientists make many field observations in the process of producing a soil map.
The frequency of observation is dependent upon several factors, including scale of
mapping, intensity of mapping, design of map units, complexity of the landscape,
and experience of the soil scientist. Observations are made to test and refine the
soil-landscape model and predictions and to verify the classification of the soils at
specific locations. Once the soil-landscape model is refined, a significantly smaller
number of measurements of individual soil properties are made and recorded.
These measurements may include field measurements, such as those for color,
depth to bedrock, and texture, and laboratory measurements, such as those for
content of sand, silt, clay, salt, and other components. Properties of each soil
typically vary from one point to another across the landscape.
Observations for map unit components are aggregated to develop ranges of
characteristics for the components. The aggregated values are presented. Direct
measurements do not exist for every property presented for every map unit
component. Values for some properties are estimated from combinations of other
properties.
While a soil survey is in progress, samples of some of the soils in the area generally
are collected for laboratory analyses and for engineering tests. Soil scientists
interpret the data from these analyses and tests as well as the field-observed
characteristics and the soil properties to determine the expected behavior of the
soils under different uses. Interpretations for all of the soils are field tested through
observation of the soils in different uses and under different levels of management.
Some interpretations are modified to fit local conditions, and some new
interpretations are developed to meet local needs. Data are assembled from other
sources, such as research information, production records, and field experience of
specialists. For example, data on crop yields under defined levels of management
are assembled from farm records and from field or plot experiments on the same
kinds of soil.
Predictions about soil behavior are based not only on soil properties but also on
such variables as climate and biological activity. Soil conditions are predictable over
long periods of time, but they are not predictable from year to year. For example,
soil scientists can predict with a fairly high degree of accuracy that a given soil will
have a high water table within certain depths in most years, but they cannot predict
that a high water table will always be at a specific level in the soil on a specific date.
After soil scientists located and identified the significant natural bodies of soil in the
survey area, they drew the boundaries of these bodies on aerial photographs and
Custom Soil Resource Report
6
identified each as a specific map unit. Aerial photographs show trees, buildings,
fields, roads, and rivers, all of which help in locating boundaries accurately.
Custom Soil Resource Report
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
9
Custom Soil Resource Report
Soil Map
39211003921200392130039214003921500392160039217003921800392100039211003921200392130039214003921500392160039217003921800358800 358900 359000 359100 359200 359300
358800 358900 359000 359100 359200 359300
35° 25' 47'' N 82° 33' 22'' W35° 25' 47'' N82° 32' 57'' W35° 25' 20'' N
82° 33' 22'' W35° 25' 20'' N
82° 32' 57'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 17N WGS84
0 150 300 600 900
Feet
0 50 100 200 300
Meters
Map Scale: 1:4,060 if printed on A portrait (8.5" x 11") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
Special Point Features
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:20,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Henderson County, North Carolina
Survey Area Data: Version 20, Jun 4, 2020
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: May 3, 2020—May 7,
2020
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.
Custom Soil Resource Report
10
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
BaB Bradson gravelly loam, 2 to 7
percent slopes
12.5 35.7%
Co Codorus loam (arkaqua)1.0 2.9%
Cu Comus (colvard) fine sandy
loam
6.3 18.0%
EnB Elsinboro loam, 0 to 3 percent
slopes
11.5 33.0%
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.
Custom Soil Resource Report
11
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.
Custom Soil Resource Report
12
Henderson County, North Carolina
BaB—Bradson gravelly loam, 2 to 7 percent slopes
Map Unit Setting
National map unit symbol: lc10
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
Custom Soil Resource Report
13
Co—Codorus loam (arkaqua)
Map Unit Setting
National map unit symbol: lc18
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
Custom Soil Resource Report
14
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: lc19
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)
Custom Soil Resource Report
15
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: lc1h
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
Custom Soil Resource Report
16
Hydric soil rating: No
Ro—Rosman loam
Map Unit Setting
National map unit symbol: lc20
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
Custom Soil Resource Report
17
Down-slope shape:Concave
Across-slope shape:Concave
Hydric soil rating: Yes
Custom Soil Resource Report
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
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.
Custom Soil Resource Report
20
21
Custom Soil Resource Report
Map—Hydrologic Soil Group (Ferncliff Ret Site (Mills River, NC))39211003921200392130039214003921500392160039217003921800392100039211003921200392130039214003921500392160039217003921800358800 358900 359000 359100 359200 359300
358800 358900 359000 359100 359200 359300
35° 25' 47'' N 82° 33' 22'' W35° 25' 47'' N82° 32' 57'' W35° 25' 20'' N
82° 33' 22'' W35° 25' 20'' N
82° 32' 57'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 17N WGS84
0 150 300 600 900
Feet
0 50 100 200 300
Meters
Map Scale: 1:4,060 if printed on A portrait (8.5" x 11") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Lines
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Points
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:20,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Henderson County, North Carolina
Survey Area Data: Version 20, Jun 4, 2020
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: May 3, 2020—May 7,
2020
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.
Custom Soil Resource Report
22
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
to 7 percent slopes
B 12.5 35.7%
Co Codorus loam (arkaqua)B/D 1.0 2.9%
Cu Comus (colvard) fine
sandy loam
B 6.3 18.0%
EnB Elsinboro loam, 0 to 3
percent slopes
B 11.5 33.0%
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
Custom Soil Resource Report
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.nrcs.usda.gov/wps/portal/
nrcs/detail/national/soils/?cid=nrcs142p2_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.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577
Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of
Agriculture, Natural Resources Conservation Service. http://
www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_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=nrcs142p2_053374
United States Department of Agriculture, Natural Resources Conservation Service.
National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/
detail/national/landuse/rangepasture/?cid=stelprdb1043084
24
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/soils/scientists/?cid=nrcs142p2_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.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?
cid=nrcs142p2_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
Custom Soil Resource Report
25
NOAA Atlas 14, Volume 2, Version 3
Location name: Mills River, North Carolina, USA*
Latitude: 35.3908°, Longitude: -82.568°
Elevation: m/ft**
* source: ESRI Maps
** source: USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring, Maryland
PF_tabular | PF_graphical | Maps_&_aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches/hour)1
Duration
Average recurrence interval (years)
1 2 5 10 25 50 100 200 500 1000
5-min 4.44
(4.00‑4.93)
5.28
(4.76‑5.86)
6.32
(5.70‑7.02)
7.12
(6.40‑7.88)
8.15
(7.27‑9.01)
8.94
(7.93‑9.88)
9.73
(8.59‑10.8)
10.5
(9.23‑11.7)
11.5
(10.0‑12.9)
12.4
(10.6‑13.9)
10-min 3.55
(3.20‑3.94)
4.22
(3.82‑4.69)
5.06
(4.57‑5.62)
5.69
(5.12‑6.30)
6.49
(5.80‑7.18)
7.12
(6.31‑7.87)
7.73
(6.83‑8.56)
8.34
(7.31‑9.26)
9.13
(7.91‑10.2)
9.74
(8.36‑11.0)
15-min 2.95
(2.66‑3.28)
3.54
(3.20‑3.93)
4.27
(3.85‑4.74)
4.80
(4.32‑5.31)
5.49
(4.90‑6.07)
6.01
(5.33‑6.64)
6.51
(5.75‑7.22)
7.01
(6.15‑7.79)
7.66
(6.64‑8.56)
8.16
(7.00‑9.17)
30-min 2.02
(1.83‑2.25)
2.44
(2.21‑2.71)
3.03
(2.73‑3.37)
3.48
(3.13‑3.85)
4.06
(3.63‑4.50)
4.52
(4.01‑5.00)
4.99
(4.41‑5.53)
5.46
(4.79‑6.06)
6.10
(5.28‑6.82)
6.60
(5.66‑7.42)
60-min 1.26
(1.14‑1.40)
1.53
(1.39‑1.70)
1.94
(1.75‑2.16)
2.26
(2.04‑2.51)
2.71
(2.41‑2.99)
3.07
(2.72‑3.39)
3.44
(3.03‑3.81)
3.83
(3.36‑4.25)
4.37
(3.79‑4.89)
4.82
(4.13‑5.42)
2-hr 0.741
(0.668‑0.822)
0.900
(0.812‑0.996)
1.14
(1.02‑1.25)
1.32
(1.19‑1.46)
1.59
(1.41‑1.76)
1.80
(1.59‑1.99)
2.03
(1.78‑2.25)
2.27
(1.97‑2.52)
2.60
(2.24‑2.90)
2.88
(2.45‑3.23)
3-hr 0.531
(0.480‑0.592)
0.640
(0.577‑0.712)
0.802
(0.722‑0.891)
0.935
(0.838‑1.04)
1.13
(1.00‑1.25)
1.29
(1.14‑1.43)
1.46
(1.28‑1.63)
1.65
(1.43‑1.84)
1.92
(1.64‑2.15)
2.14
(1.80‑2.42)
6-hr 0.339
(0.310‑0.373)
0.404
(0.369‑0.444)
0.498
(0.454‑0.547)
0.579
(0.525‑0.636)
0.695
(0.626‑0.764)
0.795
(0.710‑0.873)
0.903
(0.798‑0.994)
1.02
(0.891‑1.13)
1.19
(1.02‑1.32)
1.34
(1.13‑1.49)
12-hr 0.211
(0.194‑0.231)
0.252
(0.232‑0.276)
0.310
(0.284‑0.338)
0.356
(0.326‑0.389)
0.420
(0.382‑0.459)
0.473
(0.429‑0.516)
0.527
(0.475‑0.577)
0.584
(0.522‑0.642)
0.663
(0.586‑0.734)
0.727
(0.636‑0.810)
24-hr 0.127
(0.118‑0.137)
0.152
(0.141‑0.165)
0.187
(0.173‑0.202)
0.214
(0.198‑0.232)
0.253
(0.233‑0.273)
0.284
(0.260‑0.306)
0.316
(0.288‑0.340)
0.349
(0.317‑0.376)
0.395
(0.356‑0.427)
0.432
(0.386‑0.468)
2-day 0.075
(0.070‑0.081)
0.090
(0.084‑0.097)
0.109
(0.102‑0.118)
0.125
(0.116‑0.134)
0.146
(0.136‑0.157)
0.164
(0.151‑0.176)
0.181
(0.167‑0.195)
0.200
(0.183‑0.215)
0.225
(0.204‑0.243)
0.245
(0.221‑0.265)
3-day 0.054
(0.050‑0.057)
0.064
(0.060‑0.068)
0.077
(0.072‑0.083)
0.088
(0.082‑0.094)
0.102
(0.095‑0.109)
0.113
(0.105‑0.121)
0.125
(0.115‑0.134)
0.137
(0.125‑0.147)
0.153
(0.139‑0.164)
0.166
(0.150‑0.179)
4-day 0.043
(0.040‑0.046)
0.051
(0.048‑0.054)
0.061
(0.057‑0.065)
0.069
(0.064‑0.074)
0.080
(0.074‑0.085)
0.088
(0.082‑0.094)
0.096
(0.089‑0.103)
0.105
(0.097‑0.112)
0.116
(0.107‑0.125)
0.126
(0.114‑0.135)
7-day 0.029
(0.027‑0.031)
0.034
(0.032‑0.036)
0.041
(0.038‑0.043)
0.046
(0.043‑0.049)
0.053
(0.050‑0.057)
0.059
(0.055‑0.063)
0.065
(0.060‑0.069)
0.071
(0.065‑0.076)
0.079
(0.072‑0.085)
0.085
(0.078‑0.092)
10-day 0.023
(0.022‑0.024)
0.027
(0.026‑0.029)
0.032
(0.030‑0.034)
0.036
(0.034‑0.038)
0.042
(0.039‑0.044)
0.046
(0.043‑0.049)
0.050
(0.047‑0.053)
0.054
(0.051‑0.058)
0.060
(0.056‑0.064)
0.065
(0.060‑0.070)
20-day 0.016
(0.015‑0.016)
0.018
(0.017‑0.019)
0.021
(0.020‑0.022)
0.023
(0.022‑0.025)
0.026
(0.025‑0.028)
0.029
(0.027‑0.030)
0.031
(0.029‑0.033)
0.033
(0.031‑0.035)
0.036
(0.033‑0.038)
0.038
(0.035‑0.040)
30-day 0.013
(0.012‑0.013)
0.015
(0.014‑0.016)
0.017
(0.016‑0.018)
0.019
(0.018‑0.020)
0.021
(0.020‑0.022)
0.022
(0.021‑0.023)
0.024
(0.022‑0.025)
0.025
(0.024‑0.026)
0.027
(0.025‑0.028)
0.028
(0.026‑0.029)
45-day 0.011
(0.010‑0.011)
0.013
(0.012‑0.013)
0.014
(0.014‑0.015)
0.015
(0.015‑0.016)
0.017
(0.016‑0.018)
0.018
(0.017‑0.019)
0.019
(0.018‑0.020)
0.019
(0.018‑0.020)
0.020
(0.019‑0.022)
0.021
(0.020‑0.022)
60-day 0.010
(0.009‑0.010)
0.011
(0.011‑0.012)
0.013
(0.012‑0.013)
0.014
(0.013‑0.014)
0.015
(0.014‑0.015)
0.015
(0.015‑0.016)
0.016
(0.015‑0.017)
0.017
(0.016‑0.018)
0.018
(0.017‑0.018)
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 NOAA Atlas 14 document for more information.
Back to Top
PF graphical
Back to Top
Maps & aerials
Small scale terrain
Large scale terrain
Large scale map
+
–
3km
2mi
+
–
100km
60mi
+
–
100km
60mi
Back to Top
US Department of Commerce
National Oceanic and Atmospheric Administration
National Weather Service
National Water Center
1325 East West Highway
Silver Spring, MD 20910
Questions?: [e-mail]
Disclaimer
+
–
100km
60mi
NOAA Atlas 14, Volume 2, Version 3
Location name: Mills River, North Carolina, USA*
Latitude: 35.3908°, Longitude: -82.568°
Elevation: m/ft**
* source: ESRI Maps
** source: USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring, Maryland
PF_tabular | PF_graphical | Maps_&_aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1
Duration
Average recurrence interval (years)
1 2 5 10 25 50 100 200 500 1000
5-min 0.370
(0.333‑0.411)
0.440
(0.397‑0.488)
0.527
(0.475‑0.585)
0.593
(0.533‑0.657)
0.679
(0.606‑0.751)
0.745
(0.661‑0.823)
0.811
(0.716‑0.898)
0.877
(0.769‑0.974)
0.962
(0.834‑1.08)
1.03
(0.885‑1.16)
10-min 0.591
(0.533‑0.656)
0.704
(0.636‑0.781)
0.844
(0.761‑0.937)
0.949
(0.853‑1.05)
1.08
(0.966‑1.20)
1.19
(1.05‑1.31)
1.29
(1.14‑1.43)
1.39
(1.22‑1.54)
1.52
(1.32‑1.70)
1.62
(1.39‑1.83)
15-min 0.738
(0.666‑0.820)
0.885
(0.799‑0.982)
1.07
(0.962‑1.19)
1.20
(1.08‑1.33)
1.37
(1.22‑1.52)
1.50
(1.33‑1.66)
1.63
(1.44‑1.80)
1.75
(1.54‑1.95)
1.92
(1.66‑2.14)
2.04
(1.75‑2.29)
30-min 1.01
(0.913‑1.12)
1.22
(1.10‑1.36)
1.52
(1.37‑1.68)
1.74
(1.56‑1.93)
2.03
(1.81‑2.25)
2.26
(2.01‑2.50)
2.49
(2.20‑2.76)
2.73
(2.39‑3.03)
3.05
(2.64‑3.41)
3.30
(2.83‑3.71)
60-min 1.26
(1.14‑1.40)
1.53
(1.39‑1.70)
1.94
(1.75‑2.16)
2.26
(2.04‑2.51)
2.71
(2.41‑2.99)
3.07
(2.72‑3.39)
3.44
(3.03‑3.81)
3.83
(3.36‑4.25)
4.37
(3.79‑4.89)
4.82
(4.13‑5.42)
2-hr 1.48
(1.34‑1.64)
1.80
(1.62‑1.99)
2.27
(2.04‑2.51)
2.65
(2.37‑2.92)
3.17
(2.82‑3.51)
3.60
(3.18‑3.99)
4.05
(3.56‑4.49)
4.53
(3.94‑5.03)
5.20
(4.47‑5.81)
5.75
(4.89‑6.46)
3-hr 1.60
(1.44‑1.78)
1.92
(1.73‑2.14)
2.41
(2.17‑2.68)
2.81
(2.52‑3.12)
3.39
(3.01‑3.76)
3.88
(3.42‑4.31)
4.39
(3.84‑4.88)
4.96
(4.29‑5.52)
5.76
(4.91‑6.47)
6.44
(5.42‑7.26)
6-hr 2.03
(1.85‑2.23)
2.42
(2.21‑2.66)
2.98
(2.72‑3.28)
3.47
(3.14‑3.81)
4.16
(3.75‑4.58)
4.76
(4.25‑5.23)
5.41
(4.78‑5.95)
6.11
(5.34‑6.74)
7.14
(6.13‑7.92)
8.01
(6.79‑8.94)
12-hr 2.55
(2.34‑2.78)
3.04
(2.79‑3.32)
3.73
(3.42‑4.08)
4.29
(3.92‑4.68)
5.06
(4.61‑5.53)
5.69
(5.16‑6.22)
6.35
(5.72‑6.95)
7.03
(6.29‑7.73)
7.99
(7.07‑8.85)
8.75
(7.67‑9.76)
24-hr 3.04
(2.82‑3.29)
3.65
(3.38‑3.95)
4.48
(4.15‑4.85)
5.14
(4.76‑5.56)
6.06
(5.59‑6.55)
6.81
(6.25‑7.35)
7.57
(6.92‑8.16)
8.37
(7.60‑9.03)
9.48
(8.54‑10.2)
10.4
(9.25‑11.2)
2-day 3.62
(3.38‑3.89)
4.32
(4.02‑4.65)
5.26
(4.89‑5.65)
6.00
(5.58‑6.45)
7.03
(6.51‑7.55)
7.86
(7.25‑8.43)
8.71
(8.01‑9.36)
9.59
(8.77‑10.3)
10.8
(9.81‑11.7)
11.8
(10.6‑12.7)
3-day 3.86
(3.61‑4.14)
4.60
(4.30‑4.93)
5.55
(5.18‑5.95)
6.31
(5.88‑6.75)
7.33
(6.81‑7.85)
8.15
(7.55‑8.72)
8.98
(8.29‑9.63)
9.83
(9.03‑10.6)
11.0
(10.0‑11.8)
11.9
(10.8‑12.9)
4-day 4.11
(3.84‑4.38)
4.89
(4.57‑5.22)
5.85
(5.47‑6.24)
6.61
(6.18‑7.06)
7.64
(7.11‑8.15)
8.44
(7.84‑9.01)
9.26
(8.56‑9.89)
10.1
(9.28‑10.8)
11.2
(10.2‑12.0)
12.1
(11.0‑13.0)
7-day 4.80
(4.50‑5.13)
5.69
(5.34‑6.10)
6.82
(6.39‑7.30)
7.72
(7.22‑8.25)
8.93
(8.32‑9.55)
9.90
(9.20‑10.6)
10.9
(10.1‑11.6)
11.9
(11.0‑12.7)
13.3
(12.1‑14.2)
14.3
(13.0‑15.4)
10-day 5.50
(5.19‑5.83)
6.50
(6.13‑6.91)
7.71
(7.28‑8.19)
8.66
(8.17‑9.20)
9.96
(9.36‑10.6)
11.0
(10.3‑11.7)
12.0
(11.2‑12.8)
13.1
(12.2‑13.9)
14.5
(13.4‑15.5)
15.6
(14.3‑16.7)
20-day 7.46
(7.07‑7.88)
8.77
(8.32‑9.27)
10.2
(9.65‑10.8)
11.3
(10.7‑11.9)
12.7
(12.0‑13.4)
13.8
(13.0‑14.6)
14.8
(14.0‑15.7)
15.8
(14.9‑16.8)
17.1
(16.0‑18.2)
18.1
(16.9‑19.3)
30-day 9.15
(8.69‑9.63)
10.7
(10.2‑11.3)
12.3
(11.7‑12.9)
13.4
(12.7‑14.1)
14.9
(14.1‑15.7)
16.0
(15.1‑16.8)
17.0
(16.1‑17.9)
18.0
(16.9‑19.0)
19.2
(18.0‑20.3)
20.0
(18.8‑21.2)
45-day 11.6
(11.1‑12.2)
13.6
(13.0‑14.3)
15.3
(14.6‑16.1)
16.6
(15.8‑17.4)
18.1
(17.2‑19.0)
19.2
(18.2‑20.1)
20.1
(19.1‑21.2)
21.0
(19.9‑22.1)
22.1
(20.9‑23.2)
22.8
(21.5‑24.0)
60-day 14.0
(13.3‑14.7)
16.3
(15.5‑17.1)
18.2
(17.3‑19.1)
19.5
(18.6‑20.5)
21.2
(20.2‑22.2)
22.3
(21.2‑23.4)
23.3
(22.2‑24.5)
24.2
(23.0‑25.5)
25.3
(23.9‑26.6)
26.0
(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 NOAA Atlas 14 document for more information.
Back to Top
PF graphical
Back to Top
Maps & aerials
Small scale terrain
Large scale terrain
Large scale map
+
–
3km
2mi
+
–
100km
60mi
+
–
100km
60mi
Back to Top
US Department of Commerce
National Oceanic and Atmospheric Administration
National Weather Service
National Water Center
1325 East West Highway
Silver Spring, MD 20910
Questions?: [e-mail]
Disclaimer
+
–
100km
60mi

Storm Drainage – Conveyance Design
DUKE ENERGY 526 S Chuch StreetCharlotte, NC 28202Transmission EngineeringProposed BUA (sf)Reserved BUA (sf)Total Max. Allow BUA (sf)station ABC access drive7,203 1000 8,203station #57 stone86,289 7000 93,2890 0EXISTING IMPERVIOUS TO REMAIN00 0Total Max. Lot BUA (SF)Parking/SidewalksGravel DriveSidewalkTotal Max. BUA in R/W (sf)Total Proposed BUA (sf)ac.Proposed Subdivided Parcel Area (ac) 432998.02 ac.Proposed Impervious %23.44%Description00Total Site Allowable BUA Summary101,4912.339.94101,491Right-of-Way (R/W) allowable BUA SummaryArea (sf)000Proposed ImperviousStation Name:Ferncliff RetStation Number:5574Original Date:10/16/20DB:JAPRevision Date:11/11/20QA:MTP
DUKE ENERGY 526 S Church StreetCharlotte, NC 28202Transmission EngineeringDI-108 DI-1070.12 10%90%0.84 7.12 0.7 0.7 0.012 1.00% 446.4124.9 3.87 0.19 0.25 0.66 3.25 0.15 0.23 2072.63 2072.19 2076.00 2.12 HDPE -DI-107 DI-106 0.23 10%90%0.84 7.12 1.3 2.1 0.012 1.00% 569.5124.9 3.87 0.54 0.50 0.99 4.88 0.34 0.42 2072.19 2071.63 2076.00 2.56 HDPE -DI-106 DI-105 0.20 10%90%0.84 7.12 1.2 3.3 0.012 1.00% 6011.2155.7 7.02 0.46 0.45 0.94 5.37 0.51 0.60 2071.63 2071.03 2076.00 2.87 HDPE -DI-105 JB-104 0.15 10%90%0.84 7.12 0.9 4.2 0.012 1.00% 5412.3155.7 7.02 0.59 0.50 0.99 5.66 0.67 0.76 2071.03 2070.49 2076.00 3.47 HDPE -JB-104 OWS 0.00 0%100%0.90 7.12 0.0 4.2 0.010 0.00% 1112.3160.0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2070.49 2070.49 2076.25 4.43 DIP -OWS JB-103 0.00 0%100%0.90 7.12 0.0 4.2 0.010 0.00% 1112.3160.0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2069.99 2069.99 2076.24 4.92 DIP -JB-103 JB-102 0.00 0%100%0.90 7.12 0.0 4.2 0.012 1.00% 7412.3186.5 11.41 0.37 0.40 0.87 5.62 0.19 0.22 2069.99 2069.25 2076.15 4.37 HDPE -JB-102 FES-101 0.00 0%100%0.90 7.12 0.0 4.2 0.012 1.49% 8511.4187.9 13.95 0.30 0.35 0.82 6.47 0.37 0.44 2069.25 2067.98 2075.75 4.71 HDPE -DI-108 DI-1070.12 10%90%0.84 8.15 0.8 0.8 0.012 1.00% 446.8124.9 3.87 0.22 0.30 0.74 3.65 0.15 0.20 2072.63 2072.19 2076.00 2.12 HDPE -DI-107 DI-106 0.23 10%90%0.84 8.15 1.5 2.4 0.012 1.00% 5610.0124.9 3.87 0.62 0.55 1.05 4.20 0.34 0.42 2072.19 2071.63 2076.00 2.56 HDPE -DI-106 DI-105 0.20 10%90%0.84 8.15 1.3 3.7 0.012 1.00% 6011.8155.7 7.02 0.53 0.50 0.99 5.66 0.51 0.60 2071.63 2071.03 2076.00 2.87 HDPE -DI-105 JB-104 0.15 10%90%0.84 8.15 1.1 4.8 0.012 1.00% 5413.0155.7 7.02 0.68 0.60 1.07 5.07 0.67 0.78 2071.03 2070.49 2076.00 3.47 HDPE -JB-104 OWS 0.00 0%100%0.90 8.15 0.0 4.8 0.010 0.00% 1113.0160.0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2070.49 2070.49 2076.25 4.43 DIP -OWS JB-103 0.00 0%100%0.90 8.15 0.0 4.8 0.010 0.00% 1113.0160.0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2069.99 2069.99 2076.24 4.92 DIP -JB-103 JB-102 0.00 0%100%0.90 8.15 0.0 4.8 0.012 1.00% 7413.0186.5 11.41 0.42 0.45 0.94 6.07 0.19 0.20 2069.99 2069.25 2076.15 4.37 HDPE -JB-102 FES-101 0.00 0%100%0.90 8.15 0.0 4.8 0.012 1.49% 8512.0187.9 13.95 0.34 0.40 0.87 6.87 0.37 0.41 2069.25 2067.98 2075.75 4.71 HDPE -xxx.xxHold receiving pipe invertxxx.xxPipe invert higher than receivingxxx.xxDrop in invertsMaterial n10/16/2011/11/20DB:Ferncliff RetStorm Network - 25-Yr/24-Hr DesignFrom StructureTo Structure(acres)Composite Runoff Coeff. CcVfull (fps)Size (in)Dtheo (in)Pipe Length (ft)Storm Drainage Calculations - Conveyance Only - (10 &25 year storms)QA:MTPInlet AreasPipe Sizing CalculationsDescriptionOriginal Date:Pipe Capacity Q-full (cfs)Q/Q-full v/V-fulld/dm ratioPipe Slope (%)Inlet Discharge Q (cfs)Combined Discharge Qpipe (cfs)Percent Impervious (%)Percent Pervious (%)I (in/hr)Station Number:5574Storm Network - 10-Yr/24-Hr DesignPipe Input/Cover CalculationsJAPRevision Date:Actual Vpipe (fps) Pipe Inv. In Pipe Inv. OutStructure Rim ElevationDepth Of Cover (Based on Rim)Pipe MaterialPipe Material ClassPipe Time (min) - Full Cond.Actual Pipe Time (min)LocationStorm Runoff
DUKE ENERGY 526 S Church Street
Charlotte, NC 28202
Transmission Engineering
d50 (ft) La (ft)
W1=Do + La
W1 (ft)
W2=3*Do W2
(ft)*T(ft)H=(2/3)*Do
H (ft)
FES-101 4.8 18 0.5 10 11.50 4.50 1.125 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)
Minimum TW Condition
Do (in)Discharge
(cfs)Outlet
Rip-Rap Apron Summary Table
8.15
8.15
8.15
8.15
101 =
0.4
101 =
4.8 cfs
101 = 9'
Minimum's apply to both the FES-101 outfall and the
driveway culvert, due to the runoff of the contributing
drainage areas.
DUKE ENERGY 526 S Church StreetCharlotte, NC 28202Transmission EngineeringOrifice Condition Weir ConditionD= (Surface Qtotal/ (0.6)* 3.66sf * 64.4^0.5)^2D=[(Surface Qtotal/ (3.3*11.08)]^2/3ConditionDepth Provided (ft)Freeboard (ft)Weir Length L (ft)D= (Surface Q/ (3.3)(L))^2/3Is D>.5H=(Surface Q/(0.6*.5*L*(64.4^.5)))^2D=H+(.5/2)Depth of Flow (ft)DI-108 0.8 0.002 0.08 Weir 0.60 0.52 N/A#VALUE! #VALUE!#VALUE! #VALUE! #VALUE!DI-107 1.5 0.008 0.12 Weir 0.60 0.48 N/A#VALUE! #VALUE!#VALUE! #VALUE! #VALUE!DI-106 1.3 0.006 0.11 Weir 0.60 0.49 N/A#VALUE! #VALUE!#VALUE! #VALUE! #VALUE!DI-105 1.1 0.004 0.09 Weir 0.60 0.51 N/A#VALUE! #VALUE!#VALUE! #VALUE! #VALUE!10/16/20DB:JAPDescriptionFerncliff RetStation Number:5574AnalysisInletSurface Q (cfs)Drop Inlet Summary TableOpen Throat Inlet CalculationsStandard DI Grate - NCDOT Type ERevision Date:11/11/20QA:MTPDrop inlet analysisOriginal Date:
10/16/20DB:11/11/20PM:Open Channel Callout:D-1*To match the plan sheetDrainage Area:90942.522.09 acWeighted Runoff CoefficientLand Cover DescriptionC-ValueArea (ac)Percentage of Total AreaWeighted CLawns0.30 1.84 88.03% 0.26Driveways/roofs/etc. 0.95 0.25 11.97% 0.11Residential Development 0.60 0.00 0.00% 0.00Total Drainage Area: 2.09 Weighted C-Value:0.38*Total drainage area must match the drainage are input above by the userStorm Event Rainfall Intensity-I (in/hr) Runoff (CFS)10-Year/24-Hour7.125.6225-Year/24-Hour8.156.4350-Year/24-Hour8.947.05*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 locationTop Elevation of Channel at start:2077.55ftBottom Elevation of Channel at end:2063.00ftLength of Channel:612ftEstimated Channel Slope:0.024 ft/ftSlope Vegetation Velocity (fps) *Design for low retardance (Class D)0-5%Tall Fescue 4.50Lining OptionsDescriptionPermissible Velocity (Vp)Manning n-Value:Option 1 9" Stone9.80 0.032Option 2 6" stone8.00 0.032Option 3 Concrete20.00 0.013Option 4 Grass-Lined 4.500.030Temp Lining 1 NAG SC1508.00 0.022Perm Lining 1 NAG ERONET P3009.00 0.030*values taken from tables and support information found on the Appendix tab5574Ferncliff RetStation Number:Permissible Velocities - Vp - Perm Grass LiningOriginal Date:Revision Date:MTPJAPEstimated RunoffChannel Parameters
10/16/20DB:11/11/20PM:5574Ferncliff RetStation Number:Original Date:Revision Date:MTPJAPBottom Width (B):2.00ftSide Slopes (M:1)4Max Depth of Channel:2.00ftCross-Sectional Area 20.00 sfWetted Perimeter 18.49 ftHydraulic Radius 1.08 ftMax Allowed Velocity8.069ft/sBest Hydraulic Section Method (Channel with good maintenance)Cm=0.595k=0.246*Data taken from appendix tabCm[Qn/sqrt(S)]^(3/8)= y =0.65 ft7.77 inDepth is Okay*assumed grass lined channel for the 25-year/24-hour storm event with a Tc of 5-minutesMax. Allowed Velocity in Channel
10/16/20DB:11/11/20PM:5574Ferncliff RetStation Number:Original Date:Revision Date:MTPJAPNormal-Depth Procedure (Channel with no maintenance)MANNINGS N:0.080unmaintained channel/brushy*conservative approachZ10 required: 1.956Z25 required: 2.239Z50 required: 2.456NORMAL DEPTH-y (ft) AREA-A (sf) WETTED PERIMETER-P (FT) HYD RADIUS-R (ft) Zav Z10 Comp Z25 Comp Z50 Comp0.100.24 2.82 0.08 0.05 NARROW NARROW NARROW0.150.39 3.24 0.12 0.10 NARROW NARROW NARROW0.200.56 3.65 0.15 0.16 NARROW NARROW NARROW0.250.75 4.06 0.18 0.24 NARROW NARROW NARROW0.300.96 4.47 0.21 0.34 NARROW NARROW NARROW0.351.19 4.89 0.24 0.46 NARROW NARROW NARROW0.401.44 5.30 0.27 0.60 NARROW NARROW NARROW0.451.71 5.71 0.30 0.77 NARROW NARROW NARROW0.502.00 6.12 0.33 0.95 NARROW NARROW NARROW0.552.31 6.54 0.35 1.15 NARROW NARROW NARROW0.602.64 6.95 0.38 1.38 NARROW NARROW NARROW0.652.99 7.36 0.41 1.64 NARROW NARROW NARROW0.703.36 7.77 0.43 1.92 NARROW NARROW NARROW0.753.75 8.18 0.46 2.23 WIDE NARROW NARROW0.804.16 8.60 0.48 2.56 WIDE WIDE WIDE0.854.59 9.01 0.51 2.93 WIDE WIDE WIDE0.905.04 9.42 0.53 3.32 WIDE WIDE WIDE0.955.51 9.83 0.56 3.74 WIDE WIDE WIDE1.006.00 10.25 0.59 4.20 WIDE WIDE WIDE1.056.51 10.66 0.61 4.69 WIDE WIDE WIDE1.107.04 11.07 0.64 5.21 WIDE WIDE WIDE1.157.59 11.48 0.66 5.76 WIDE WIDE WIDE1.208.16 11.90 0.69 6.35 WIDE WIDE WIDE1.258.75 12.31 0.71 6.97 WIDE WIDE WIDE1.309.36 12.72 0.74 7.63 WIDE WIDE WIDE1.359.99 13.13 0.76 8.32 WIDE WIDE WIDE1.4010.64 13.54 0.79 9.06 WIDE WIDE WIDE1.4511.31 13.96 0.81 9.83 WIDE WIDE WIDE1.5012.00 14.37 0.84 10.64 WIDE WIDE WIDE1.5512.71 14.78 0.86 11.49 WIDE WIDE WIDE1.6013.44 15.19 0.88 12.38 WIDE WIDE WIDEREMARKS
10/16/20DB:11/11/20PM:5574Ferncliff RetStation Number:Original Date:Revision Date:MTPJAP1.6514.19 15.61 0.91 13.32 WIDE WIDE WIDE1.7014.96 16.02 0.93 14.29 WIDE WIDE WIDE1.7515.75 16.43 0.96 15.31 WIDE WIDE WIDE1.8016.56 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 InterpolationNormal Depth - y (ft)Zav0.752.23x2.239*25-year storm0.802.56x=0.75 ft9.02 inVelocity Calculations based on Channel DimensionsV=[1.49*R^(2/3)S^(1/2)]/nLining OptionsDescriptionCalculated Velocity-V (fps)Velocity CheckOption 19" Stone4.35Velocity OKOption 26" stone4.35Velocity OKOption 3Concrete10.70redesignOption 4Grass-Lined4.64redesignTemp Lining 1NAG SC1506.32Velocity OKPerm Lining 1NAG ERONET P3004.64Velocity OKTractive Force CalculationsShear Stress at Normal DepthT=wds1.115 lb/sfw = unit weight of water62.4lb/cfd = flow depth0.75 fts = channel slope0.024 ft/ftTd = permissible shear stress (temp)2.00lb/sf Temp lining permissible shear stressLining OKNAG SC150 W/RIP-RAP CHECK DAMSTd = permissible shear stress (perm)3.00lb/sf Perm lining permissable shear stressLining OKERONET P300 & TALL FESCUE
North American Green
5401 St. Wendel-Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v7.0
CHANNEL ANALYSIS
> > >D1
Name D1
Discharge 6.43
Channel Slope 0.024
Channel Bottom Width 2
Left Side Slope 4
Right Side Slope 4
Low Flow Liner
Retardence Class E <2 in
Vegetation Type None
Vegetation Density None
Soil Type Silt Loam (SM)
SC150
Phase Reach Discharge Velocity
Normal
Depth Mannings N Permissible
Shear Stress
Calculated
Shear Stress
Safety
Factor Remarks Staple
Pattern
SC150
Unvegetated
Straight 6.43 cfs 4.41 ft/s 0.4 ft 0.022 2 lbs/ft2 0.6 lbs/ft2 3.31 STABLE D
Underlying
Substrate
Straight 6.43 cfs 4.41 ft/s 0.4 ft 0.022 1.47 lbs/ft2 0.41 lbs/ft2 3.58 STABLE D
P300
Phase Reach Discharge Velocity
Normal
Depth Mannings N Permissible
Shear Stress
Calculated
Shear Stress
Safety
Factor Remarks Staple
Pattern
P300
Unvegetated
Straight 6.43 cfs 4.41 ft/s 0.4 ft 0.022 2.3 lbs/ft2 0.6 lbs/ft2 3.81 STABLE E
Underlying
Substrate
Straight 6.43 cfs 4.41 ft/s 0.4 ft 0.022 1.68 lbs/ft2 0.41 lbs/ft2 4.11 STABLE E
P300 Reinforced
Vegetation
Straight 6.43 cfs 4.41 ft/s 0.4 ft 0.022 10 lbs/ft2 0.6 lbs/ft2 16.56 STABLE E
Underlying
Substrate
Straight 6.43 cfs 4.41 ft/s 0.4 ft 0.022 2.3 lbs/ft2 0.41 lbs/ft2 5.61 STABLE E
10/16/20DB:11/11/20PM:Open Channel Callout:D-2*To match the plan sheetDrainage Area:55994.811.29 acWeighted Runoff CoefficientLand Cover DescriptionC-ValueArea (ac)Percentage of Total AreaWeighted CLawns 0.30 0.89 68.88% 0.21Driveways/roofs/etc. 0.95 0.40 31.12% 0.30Residential Development 0.60 0.00 0.00% 0.00Total Drainage Area: 1.29 Weighted C-Value:0.50*Total drainage area must match the drainage are input above by the userStorm Event Rainfall Intensity-I (in/hr) Runoff (CFS)10-Year/24-Hour7.124.6025-Year/24-Hour8.155.2650-Year/24-Hour8.945.77*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 locationTop Elevation of Channel at start:2070.00ftBottom Elevation of Channel at end:2063.00ftLength of Channel:372ftEstimated Channel Slope:0.019 ft/ftSlope Vegetation Velocity (fps) *Design for low retardance (Class D)0-5% Tall Fescue 4.50Lining OptionsDescriptionPermissible Velocity (Vp)Manning n-Value:Option 1 9" Stone9.80 0.032Option 2 6" stone8.00 0.032Option 3 Concrete20.00 0.013Option 4 Grass-Lined 4.500.030Temp Lining 1 Straw Mat5.00 0.028Temp Lining 2 Straw/Coconut Mix5.00 0.025*values taken from tables and support information found on the Appendix tabRevision Date:MTPFerncliff RetStation Number:5574Original Date:JAPEstimated RunoffChannel ParametersPermissible Velocities - Vp - Perm Grass Lining
10/16/20DB:11/11/20PM:Revision Date:MTPFerncliff RetStation Number:5574Original Date:JAPBottom Width (B):1.00ftSide Slopes (M:1)4Max Depth of Channel:1.00ftCross-Sectional Area 5.00 sfWetted Perimeter 9.25 ftHydraulic Radius 0.54 ftMax Allowed Velocity4.525ft/sBest Hydraulic Section Method (Channel with good maintenance)Cm=0.595k=0.246*Data taken from appendix tabCm[Qn/sqrt(S)]^(3/8)= y =0.63 ftDepth is Okay*assumed grass lined channel for the 25-year/24-hour storm event with a Tc of 5-minutesMax. Allowed Velocity in Channel
10/16/20DB:11/11/20PM:Revision Date:MTPFerncliff RetStation Number:5574Original Date:JAPNormal-Depth Procedure (Channel with no maintenance)MANNINGS N:0.080unmaintained channel/brushyZ10 required: 1.798Z25 required: 2.058Z50 required: 2.258NORMAL DEPTH-y (ft) AREA-A (sf) WETTED PERIMETER-P (FT) HYD RADIUS-R (ft) Zav Z10 Comp Z25 Comp Z50 Comp0.10 0.14 1.82 0.08 0.03 NARROW NARROW NARROW0.15 0.24 2.24 0.11 0.05 NARROW NARROW NARROW0.20 0.36 2.65 0.14 0.10 NARROW NARROW NARROW0.25 0.50 3.06 0.16 0.15 NARROW NARROW NARROW0.30 0.66 3.47 0.19 0.22 NARROW NARROW NARROW0.35 0.84 3.89 0.22 0.30 NARROW NARROW NARROW0.40 1.04 4.30 0.24 0.40 NARROW NARROW NARROW0.45 1.26 4.71 0.27 0.52 NARROW NARROW NARROW0.50 1.50 5.12 0.29 0.66 NARROW NARROW NARROW0.55 1.76 5.54 0.32 0.82 NARROW NARROW NARROW0.60 2.04 5.95 0.34 1.00 NARROW NARROW NARROW0.65 2.34 6.36 0.37 1.20 NARROW NARROW NARROW0.70 2.66 6.77 0.39 1.43 NARROW NARROW NARROW0.75 3.00 7.18 0.42 1.68 NARROW NARROW NARROW0.80 3.36 7.60 0.44 1.95 WIDE NARROW NARROW0.85 3.74 8.01 0.47 2.25 WIDE WIDE NARROW0.90 4.14 8.42 0.49 2.58 WIDE WIDE WIDE0.95 4.56 8.83 0.52 2.93 WIDE WIDE WIDE1.00 5.00 9.25 0.54 3.32 WIDE WIDE WIDE1.05 5.46 9.66 0.57 3.73 WIDE WIDE WIDE1.10 5.94 10.07 0.59 4.18 WIDE WIDE WIDE1.15 6.44 10.48 0.61 4.65 WIDE WIDE WIDE1.20 6.96 10.90 0.64 5.16 WIDE WIDE WIDE1.25 7.50 11.31 0.66 5.70 WIDE WIDE WIDE1.30 8.06 11.72 0.69 6.28 WIDE WIDE WIDE1.35 8.64 12.13 0.71 6.89 WIDE WIDE WIDE1.40 9.24 12.54 0.74 7.54 WIDE WIDE WIDE1.45 9.86 12.96 0.76 8.22 WIDE WIDE WIDE1.50 10.50 13.37 0.79 8.94 WIDE WIDE WIDE1.55 11.16 13.78 0.81 9.70 WIDE WIDE WIDEREMARKS
10/16/20DB:11/11/20PM:Revision Date:MTPFerncliff RetStation Number:5574Original Date:JAP1.60 11.84 14.19 0.83 10.49 WIDE WIDE WIDE1.65 12.54 14.61 0.86 11.33 WIDE WIDE WIDE1.70 13.26 15.02 0.88 12.20 WIDE WIDE WIDE1.75 14.00 15.43 0.91 13.12 WIDE WIDE WIDE1.80 14.76 15.84 0.93 14.08 WIDE WIDE WIDE*analyze the normal depth and the limited depth based on site grading limitsNormal Depth InterpolationNormal Depth - y (ft)Zav0.80 1.95x 2.058*25-year storm0.85 2.25x=0.82 ft9.82 inVelocity Calculations based on Channel DimensionsV=[1.49*R^(2/3)S^(1/2)]/nLining OptionsDescriptionCalculated Velocity-V (fps)Velocity CheckOption 19" Stone3.78Velocity OKOption 26" stone3.78Velocity OKOption 3Concrete9.30redesignOption 4Grass-Lined4.03Velocity OKTemp Lining 1Straw Mat4.32Velocity OKTemp Lining 2Straw/Coconut Mix4.84redesignTractive Force CalculationsShear Stress at Normal DepthT=wds0.962 lb/sfw = unit weight of water62.4lb/cfd = flow depth0.82 fts = channel slope0.019 ft/ftTd = permissible shear stress (temp)1.75lb/sf Temp lining permissible shear stressLining OKStraw MatTd = permissible shear stress (perm)1.50lb/sf Perm lining permissable shear stressLining OKGrass-Lined*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.

Erosion Control Design

Skimmer Basin (SK-1)
Project Name:Objective:Station No:Duke Project No:Location:Calc By:JAPDate:4/21/2020Checked By:JAPDate:0.60 Runoff Coefficient = CFlow to Trap:Q= CIA Rational Method7.15 Rainfall Intensity (in/hr) = I *10-year event from NOAA IDF data3.46 Drainage Area (Acres)3.46 Disturbed Area (Acres)14.84 Peak Flow from 10-year Storm (cfs) 6,227Required Volume ft34,824Required Surface Area ft250.0 Suggested Width ft100.0Suggested Length ft63 Trial Top Width at Spillway Invert ft179 Trial Top Length at Spillway Invert ft2.0 Trial Side Slope Ratio Z:12.0 Sediment Cleanout Depth ft4.0 Storage Depth ft53 Bottom Width ft163 Bottom Length ft37,472Actual Volume ft3Okay11,106Actual Surface Area ft2 OkayElevation (ft) Depth (ft) Surface Area (sf)Cummulative Volume (cf)Spillway Design Pass Flow (Qe) = Q1020500.07,6930Qe =14.84 cfsSpillway Length Calculated20511.08,5088,101Weir Constant: C = 2.8 constant for broad crested weir20522.09,34917,029Depth of Flow: H = 0.5 ft20533.010,21526,811Spillway Length Required = 15.00 ft20544.011,10637,472Spilllway Capacity = 14.85cfs20555.012,02249,03620566.012,96461,529Bottom of Basin: 2050.00 ftSediment Cleanout Elevation: 2052.00 ftSediment Storage Elevation: 2054.00 ftEmergency Spillway Crest: 2055.00 ftTop of Dam:2056.00ftElevation Summary of BasinCalculate Skimmer Basin size requirements using the manning equationDesigned Sediment Basin VolumeTemporary Skimmer Basin: SK-1 (Phase 1)DUKE ENERGY CAROLINAS, LLC (F-0566)Description:Existing Skimmer basin located North of substation pad. Basin to remain throughout the end of construction.Ferncliff Ret (New Substation)5574W18019501Mills River, NC, Henderson CountyAt primary spillway elevationEmergency Spillway Design
2.00 Skimmer Size (inches) Skimmer Size0.167 Head on Skimmer (feet) (Inches)1.50 Orifice Size (1/4 inch increments) 1.52.93 Dewatering Time (days) 2Suggest about 3 days 2.534568
Calculate Skimmer SizeBasin Volume in Cubic Feet6,227 Cu.FtSkimmer Size 2.0InchDays to Drain*3 Days Orifice Radius0.8Inch[es]Orifice Diameter1.5Inch[es]*In NC assume 3 days to drainEstimate Volume of BasinLength WidthTop of water surface in feetFeetVOLUME 0Cu. Ft.Bottom dimensions in feetFeetDepth in feetFeet
Project Name:Objective:Station No:Duke Project No:Location:Calc By:JAPDate:4/21/2020Checked By:JAPDate:0.60 Runoff Coefficient = CFlow to Trap:Q= CIA Rational Method7.15 Rainfall Intensity (in/hr) = I *10-year event from NOAA IDF data7.69 Drainage Area (Acres)7.69 Disturbed Area (Acres)32.98 Peak Flow from 10-year Storm (cfs) 13,838Required Volume ft310,718Required Surface Area ft274.0 Suggested Width ft148.0Suggested Length ft63 Trial Top Width at Spillway Invert ft179 Trial Top Length at Spillway Invert ft2.0 Trial Side Slope Ratio Z:12.0 Sediment Cleanout Depth ft4.0 Storage Depth ft53 Bottom Width ft163 Bottom Length ft37,472Actual Volume ft3Okay11,106Actual Surface Area ft2 OkayElevation (ft) Depth (ft) Surface Area (sf)Cummulative Volume (cf)Spillway Design Pass Flow (Qe) = Q1020500.07,6930Qe =32.98 cfsSpillway Length Calculated20511.08,5088,101Weir Constant: C = 2.8 constant for broad crested weir20522.09,34917,029Depth of Flow: H = 0.5 ft20533.010,21526,811Spillway Length Required = 34.00 ft20544.011,10637,472Spilllway Capacity = 33.66cfs20555.012,02249,03620566.012,96461,529Bottom of Basin: 2050.00 ftSediment Cleanout Elevation: 2052.00 ftSediment Storage Elevation: 2054.00 ftEmergency Spillway Crest: 2055.00 ftTop of Dam:2056.00ftTemporary Skimmer Basin: SK-1 (Phase 2)DUKE ENERGY CAROLINAS, LLC (F-0566)Description:Existing Skimmer basin located North of substation pad. Basin to remain throughout the end of construction.Ferncliff Ret (New Substation)Calculate Skimmer Basin size requirements using the manning equationElevation Summary of Basin5574W18019501Mills River, NC, Henderson CountyAt primary spillway elevationDesigned Sediment Basin VolumeEmergency Spillway Design
2.50 Skimmer Size (inches) Skimmer Size0.208 Head on Skimmer (feet) (Inches)2.25 Orifice Size (1/4 inch increments) 1.52.59 Dewatering Time (days) 2Suggest about 3 days 2.534568
Calculate Skimmer SizeBasin Volume in Cubic Feet13,838 Cu.FtSkimmer Size 2.5InchDays to Drain*3 Days Orifice Radius1.1Inch[es]Orifice Diameter2.2Inch[es]*In NC assume 3 days to drainEstimate Volume of BasinLength WidthTop of water surface in feetFeetVOLUME 0Cu. Ft.Bottom dimensions in feetFeetDepth in feetFeet

Skimmer Basin (SK-2)
Project Name:Objective:Station No:Duke Project No:Location:Calc By:JAPDate:4/21/2020Checked By:JAPDate:0.60 Runoff Coefficient = CFlow to Trap:Q= CIA Rational Method7.15 Rainfall Intensity (in/hr) = I *10-year event from NOAA IDF data1.92 Drainage Area (Acres)1.92 Disturbed Area (Acres)8.24 Peak Flow from 10-year Storm (cfs) 3,459Required Volume ft32,680Required Surface Area ft237.0 Suggested Width ft74.0Suggested Length ft46 Trial Top Width at Spillway Invert ft102 Trial Top Length at Spillway Invert ft2.0 Trial Side Slope Ratio Z:11.5 Sediment Cleanout Depth ft3.0 Storage Depth ft83 Bottom Width ft26 Bottom Length ft8,123Actual Volume ft3Okay3,422Actual Surface Area ft2 OkayElevation (ft) Depth (ft) Surface Area (sf)Cummulative Volume (cf)Spillway Design Pass Flow (Qe) = Q1020570.02,0330Qe = 8.24 cfsSpillway Length Calculated20581.02,4662,250Weir Constant: C = 2.8 constant for broad crested weir20592.02,9294,947Depth of Flow: H = 0.5 ft20603.03,4228,123Spillway Length = 10.00 ft Min spillway length is 10 ft20614.03,94311,805Spilllway Capacity = 9.90cfs20625.04,49316,023Bottom of Basin: 2057.00 ftSediment Cleanout Elevation: 2058.50 ftSediment Storage Elevation: 2060.00 ftEmergency Spillway Crest: 2061.00 ftTemporary Skimmer Basin: SK-2 (Phase 1)DUKE ENERGY CAROLINAS, LLC (F-0566)Description:Existing Skimmer basin located along Broadpointe Road, south of the proposed substation pad. - Phase 1 Calculations for existing storage capacity.Ferncliff Ret (New Substation)Calculate Skimmer Basin size requirements using the manning equationElevation Summary of Basin5574W18019501Mills River, NC, Henderson CountyAt primary spillway elevationDesigned Sediment Basin VolumeEmergency Spillway Design
Top of Dam:2062.00ft1.50 Skimmer Size (inches) Skimmer Size0.125 Head on Skimmer (feet) (Inches)1.25 Orifice Size (1/4 inch increments) 1.52.71 Dewatering Time (days) 2Suggest about 3 days 2.534568
Calculate Skimmer SizeBasin Volume in Cubic Feet3,459 Cu.FtSkimmer Size 1.5InchDays to Drain*3 Days Orifice Radius0.6Inch[es]Orifice Diameter1.2Inch[es]*In NC assume 3 days to drainEstimate Volume of BasinLength WidthTop of water surface in feetFeetVOLUME 0Cu. Ft.Bottom dimensions in feetFeetDepth in feetFeet
Project Name:Objective:Station No:Duke Project No:Location:Calc By:JAPDate:4/21/2020Checked By:JAPDate:0.60 Runoff Coefficient = CFlow to Trap:Q= CIA Rational Method7.15 Rainfall Intensity (in/hr) = I *10-year event from NOAA IDF data1.46 Drainage Area (Acres)1.46 Disturbed Area (Acres)6.26 Peak Flow from 10-year Storm (cfs) 2,628Required Volume ft32,036Required Surface Area ft232.0 Suggested Width ft64.0Suggested Length ft46 Trial Top Width at Spillway Invert ft102 Trial Top Length at Spillway Invert ft2.0 Trial Side Slope Ratio Z:11.5 Sediment Cleanout Depth ft3.0 Storage Depth ft83 Bottom Width ft26 Bottom Length ft8,123Actual Volume ft3Okay3,422Actual Surface Area ft2 OkayElevation (ft) Depth (ft) Surface Area (sf)Cummulative Volume (cf)Spillway Design Pass Flow (Qe) = Q1020570.02,0330Qe = 6.26 cfsSpillway Length Calculated20581.02,4662,250Weir Constant: C = 2.8 constant for broad crested weir20592.02,9294,947Depth of Flow: H = 0.5 ft20603.03,4228,123Spillway Length = 10.00 ft Min spillway length is 10 ft20614.03,94311,805Spilllway Capacity = 9.90cfs20625.04,49316,023Bottom of Basin: 2057.00 ftSediment Cleanout Elevation: 2058.50 ftSediment Storage Elevation: 2060.00 ftEmergency Spillway Crest: 2061.00 ftElevation Summary of Basin5574W18019501Mills River, NC, Henderson CountyAt primary spillway elevationDesigned Sediment Basin VolumeEmergency Spillway DesignTemporary Skimmer Basin: SK-2 (Phase 2)DUKE ENERGY CAROLINAS, LLC (F-0566)Description:Existing Skimmer basin located along Broadpointe Road, south of the proposed substation pad. - Phase 2 Calculations for proposed basin rework.Ferncliff Ret (New Substation)Calculate Skimmer Basin size requirements using the manning equation
Top of Dam:2062.00ft1.50 Skimmer Size (inches) Skimmer Size0.125 Head on Skimmer (feet) (Inches)1.00 Orifice Size (1/4 inch increments) 1.53.22 Dewatering Time (days) 2Suggest about 3 days 2.534568
Calculate Skimmer SizeBasin Volume in Cubic Feet2,628 Cu.FtSkimmer Size 1.5InchDays to Drain*3 Days Orifice Radius0.5Inch[es]Orifice Diameter1.1Inch[es]*In NC assume 3 days to drainEstimate Volume of BasinLength WidthTop of water surface in feetFeetVOLUME 0Cu. Ft.Bottom dimensions in feetFeetDepth in feetFeet

Skimmer Basin (SK-3)
Project Name:Ferncliff Ret (New Substation)Objective:Station No:Duke Project No:Location:Calc By:JAPDate:4/21/2020Checked By:JAPDate:0.60 Runoff Coefficient = CFlow to Trap:Q= CIA Rational Method7.15 Rainfall Intensity (in/hr) = I *10-year event from NOAA IDF data4.29 Drainage Area (Acres)4.29 Disturbed Area (Acres)18.41 Peak Flow from 10-year Storm (cfs) 7,725Required Volume ft35,984Required Surface Area ft255.0 Suggested Width ft110.0Suggested Length ft89 Trial Top Width at Spillway Invert ft171 Trial Top Length at Spillway Invert ft2.0 Trial Side Slope Ratio Z:11.0 Sediment Cleanout Depth ft2.0 Storage Depth ft74 Bottom Width ft153 Bottom Length ft24,170Actual Volume ft3Okay13,014Actual Surface Area ft2 OkayElevation (ft) Depth (ft) Surface Area (sf)Cummulative Volume (cf)Spillway Design Pass Flow (Qe) = Q1020500.011,1690Qe = 18.41 cfsSpillway Length Calculated20511.012,07811,624Weir Constant: C = 2.8 constant for broad crested weir20522.013,01424,170Depth of Flow: H = 0.5 ft20533.013,97737,665Spillway Length = 19.00 ft20544.014,96752,137Spilllway Capacity = 18.81cfsBottom of Basin: 2050.00 ftSediment Cleanout Elevation: 2051.00 ftSediment Storage Elevation: 2052.00 ftEmergency Spillway Crest: 2053.00 ftTemporary Skimmer Basin: SK-3DUKE ENERGY CAROLINAS, LLC (F-0566)Description:Existing sediment basin present during phase 1 erosion control only - this will be filled as part of phas 2 erosion control plan and runoff diverted to Existing Skimmer Basin #1Calculate Skimmer Basin size requirements using the manning equationElevation Summary of Basin5574W18019501Mills River, NC, Henderson CountyAt primary spillway elevationDesigned Sediment Basin VolumeEmergency Spillway Design
Top of Dam:2054.00ft2.00 Skimmer Size (inches) Skimmer Size0.167 Head on Skimmer (feet) (Inches)1.75 Orifice Size (1/4 inch increments) 1.52.67 Dewatering Time (days) 2Suggest about 3 days 2.534568
Calculate Skimmer SizeBasin Volume in Cubic Feet7,725 Cu.FtSkimmer Size 2.0InchDays to Drain*3 Days Orifice Radius0.9Inch[es]Orifice Diameter1.7Inch[es]*In NC assume 3 days to drainEstimate Volume of BasinLength WidthTop of water surface in feetFeetVOLUME 0Cu. Ft.Bottom dimensions in feetFeetDepth in feetFeet

Skimmer Basin (SK-4)
Project Name:Ferncliff Ret (New Substation)Objective:Station No:Duke Project No:Location:Calc By:JAPDate:9/30/2020Checked By:JAPDate:0.60 Runoff Coefficient = CFlow to Trap:Q= CIA Rational Method7.15 Rainfall Intensity (in/hr) = I *10-year event from NOAA IDF data3.07 Drainage Area (Acres)3.07 Disturbed Area (Acres)13.18 Peak Flow from 10-year Storm (cfs) 5,528Required Volume ft34,282Required Surface Area ft247.0 Suggested Width ft94.0Suggested Length ft56 Trial Top Width at Spillway Invert ft108 Trial Top Length at Spillway Invert ft2.0 Trial Side Slope Ratio Z:11.5 Sediment Cleanout Depth ft3.0 Storage Depth ft56 Bottom Width ft108 Bottom Length ft11,791Actual Volume ft3Okay4,837Actual Surface Area ft2 OkayElevation (ft) Depth (ft) Surface Area (sf)Cummulative Volume (cf)Spillway Design Pass Flow (Qe) = Q1020590.03,1350Qe = 13.18 cfsSpillway Length Calculated20601.03,6223,379Weir Constant: C = 2.8 constant for broad crested weir20612.04,1837,281Depth of Flow: H = 0.5 ft20623.04,83711,791Spillway Length = 14.00 ft20634.06,81217,616Spilllway Capacity = 13.86cfs2063.54.58,03625,040Bottom of Basin: 2059.00 ftSediment Cleanout Elevation: 2060.50 ftSediment Storage Elevation: 2062.00 ftEmergency Spillway Crest: 2063.00 ftElevation Summary of BasinTemporary Skimmer Basin: SK-4DUKE ENERGY CAROLINAS, LLC (F-0566)Description:Existing sediment basin present during phase 1 erosion control only - this will be filled as part of phas 2 erosion control plan and runoff diverted to Existing Skimmer Basin #1Calculate Skimmer Basin size requirements using the manning equation5574W18019501Mills River, NC, Henderson CountyAt primary spillway elevationDesigned Sediment Basin VolumeEmergency Spillway Design
Top of Dam:2064.00ft2.00 Skimmer Size (inches) Skimmer Size0.167 Head on Skimmer (feet) (Inches) df 1.50 Orifice Size (1/4 inch increments) 1.52.60 Dewatering Time (days) 2Suggest about 3 days 2.534568
Calculate Skimmer SizeBasin Volume in Cubic Feet5,528 Cu.FtSkimmer Size 2.0InchDays to Drain*3 Days Orifice Radius0.7Inch[es]Orifice Diameter1.4Inch[es]*In NC assume 3 days to drainEstimate Volume of BasinLength WidthTop of water surface in feetFeetVOLUME 0Cu. Ft.Bottom dimensions in feetFeetDepth in feetFeet

Temporary Diversion
Calculations
10/16/20Design Eng:11/11/20Checked By:Temp. Diversion CalloutMax. Contributing Drainage Area (ac)Diversion Length (ft) Upstream Elevation (ft)Downstream Elevation (ft)Slope (%)TD-10.33 91 2070 2068 2.20%TD-21.2 279 2072 2068 1.43%TD-31.13 214 2070 2068 0.93%TD-42.17 562 2071 2066 0.89%TD-51.59 473 2071 2066 1.06%TD-60.28 228 2071 2068 1.32%TD-71.22 283 2071 2062 3.18%TD-81.46 516 2071 2066 0.97%Drainage Area:94525.20 2.17 acWeighted Runoff CoefficientLand Cover DescriptionC-ValueArea (ac)Percentage of Total AreaWeighted CBare Soil0.60 2.17 100.00% 0.60Max. Total Drainage Area: 2.17 Weighted C-Value:0.60Storm Event Rainfall Intensity-I (in/hr) Runoff (CFS)10-Year/24-Hour7.129.2725-Year/24-Hour8.1510.6150-Year/24-Hour8.9411.64*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 locationMin. Channel Slope:0.009 ft/ft*use for normal depthMax. Channel Slope:0.032 ft/ft*use for shear strengthTemporary Diversions - Phase 15574Ferncliff RetStation Number:Original Date:Revision Date:MTPJAPEstimated RunoffChannel Parameters
10/16/20Design Eng:11/11/20Checked By:5574Ferncliff RetStation Number:Original Date:Revision Date:MTPJAPLining OptionsDescriptionPermissible Velocity (Vp)Manning n-Value:Natural Soil Sandy Silt Bare Soil2.00 0.025Natural Soil Silt Clay Bare Soil3.50 0.025Natural Soil Clay Bare Soil6.00 0.025Option 1 Grass-Lined/Straw Liner 7.000.033Temp Lining 1 NAG SC1508.00 0.035Temp Lining 2 Straw Mat/No vegetation7.00 0.035*values taken from tables and support information found on the Appendix tabBottom Width (B):1.00ftSide Slopes (M:1)2Max Depth of Channel:2.00ftPermissible Velocities - Vp - Perm Grass LiningManning n for clean, weathered channel
10/16/20Design Eng:11/11/20Checked By:5574Ferncliff RetStation Number:Original Date:Revision Date:MTPJAPCross-Sectional Area 10.00 sfWetted Perimeter 9.94 ftHydraulic Radius 1.01 ftMax Allowed Velocity10.668ft/sBest Hydraulic Section Method (Channel with good maintenance)Cm=0.729k=0.472*Data taken from appendix tabCm[Qn/sqrt(S)]^(3/8)= y =0.94 ft11.27 inDepth is Okay*assumed grass lined channel for the 25-year/24-hour storm event with a Tc of 5-minutesNormal-Depth Procedure (Channel with no maintenance)MANNINGS N:0.033*conservative approachZ10 required: 2.177Z25 required: 2.492Z50 required: 2.733Z10 required: 1.151Z25 required: 1.318Z50 required: 1.446NORMAL DEPTH-y (ft) AREA-A (sf) WETTED PERIMETER-P (FT) HYD RADIUS-R (ft) Zav Z10 Comp Z25 Comp Z50 Comp Z10 Comp Z25 Comp Z50 Comp0.100.12 1.45 0.08 0.02 NARROW NARROW NARROW NARROW NARROW NARROW0.150.20 1.67 0.12 0.05 NARROW NARROW NARROW NARROW NARROW NARROW0.200.28 1.89 0.15 0.08 NARROW NARROW NARROW NARROW NARROW NARROW0.250.38 2.12 0.18 0.12 NARROW NARROW NARROW NARROW NARROW NARROW0.300.48 2.34 0.20 0.17 NARROW NARROW NARROW NARROW NARROW NARROW0.350.60 2.57 0.23 0.22 NARROW NARROW NARROW NARROW NARROW NARROW0.400.72 2.79 0.26 0.29 NARROW NARROW NARROW NARROW NARROW NARROW0.450.86 3.01 0.28 0.37 NARROW NARROW NARROW NARROW NARROW NARROW0.501.00 3.24 0.31 0.46 NARROW NARROW NARROW NARROW NARROW NARROW0.551.16 3.46 0.33 0.56 NARROW NARROW NARROW NARROW NARROW NARROW0.601.32 3.68 0.36 0.67 NARROW NARROW NARROW NARROW NARROW NARROW0.651.50 3.91 0.38 0.79 NARROW NARROW NARROW NARROW NARROW NARROW0.701.68 4.13 0.41 0.92 NARROW NARROW NARROW NARROW NARROW NARROW0.751.88 4.35 0.43 1.07 NARROW NARROW NARROW NARROW NARROW NARROW0.802.08 4.58 0.45 1.23 NARROW NARROW NARROW WIDE NARROW NARROWMax. Allowed Velocity in ChannelREMARKS BASED ON MAX SLOPEREMARKS BASED ON MIN SLOPEBased on Min. SlopeBased on Max. Slope
10/16/20Design Eng:11/11/20Checked By:5574Ferncliff RetStation Number:Original Date:Revision Date:MTPJAP0.852.30 4.80 0.48 1.40 NARROW NARROW NARROW WIDE WIDE NARROW0.902.52 5.02 0.50 1.59 NARROW NARROW NARROW WIDE WIDE WIDE0.952.76 5.25 0.52 1.79 NARROW NARROW NARROW WIDE WIDE WIDE1.003.00 5.47 0.55 2.01 NARROW NARROW NARROW WIDE WIDE WIDE1.053.26 5.70 0.57 2.24 WIDE NARROW NARROW WIDE WIDE WIDE1.103.52 5.92 0.59 2.49 WIDE NARROW NARROW WIDE WIDE WIDE1.153.80 6.14 0.62 2.75 WIDE WIDE WIDE WIDE WIDE WIDE1.204.08 6.37 0.64 3.03 WIDE WIDE WIDE WIDE WIDE WIDE1.254.38 6.59 0.66 3.33 WIDE WIDE WIDE WIDE WIDE WIDE1.304.68 6.81 0.69 3.64 WIDE WIDE WIDE WIDE WIDE WIDE1.355.00 7.04 0.71 3.97 WIDE WIDE WIDE WIDE WIDE WIDE1.405.32 7.26 0.73 4.32 WIDE WIDE WIDE WIDE WIDE WIDE1.455.66 7.48 0.76 4.69 WIDE WIDE WIDE WIDE WIDE WIDE1.506.00 7.71 0.78 5.08 WIDE WIDE WIDE WIDE WIDE WIDE1.556.36 7.93 0.80 5.48 WIDE WIDE WIDE WIDE WIDE WIDE1.606.72 8.16 0.82 5.91 WIDE WIDE WIDE WIDE WIDE WIDE1.657.10 8.38 0.85 6.35 WIDE WIDE WIDE WIDE WIDE WIDE1.707.48 8.60 0.87 6.81 WIDE WIDE WIDE WIDE WIDE WIDE1.757.88 8.83 0.89 7.30 WIDE WIDE WIDE WIDE WIDE WIDE1.808.28 9.05 0.91 7.80 WIDE WIDE WIDE 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 InterpolationNormal Depth - y (ft)Zav1.102.49x2.492*25-year storm1.152.75x=1.10 ft13.20 in
10/16/20Design Eng:11/11/20Checked By:5574Ferncliff RetStation Number:Original Date:Revision Date:MTPJAPVelocity Calculations based on Channel DimensionsV=[1.49*R^(2/3)S^(1/2)]/nLining OptionsDescriptionCalculated Velocity-V (fps)Velocity CheckNatural SoilSandy Silt Bare Soil7.61redesignNatural SoilSilt Clay Bare Soil7.61redesignNatural SoilClay Bare Soil7.61redesignOption 1Grass-Lined/Straw Liner5.77Velocity OKTemp Lining 1NAG SC1505.44Velocity OKTemp Lining 2Straw Mat/No vegetation5.44Velocity OKTractive Force CalculationsShear Stress at Normal DepthT=wds2.184 lb/sfw = unit weight of water62.4lb/cfd = flow depth1.10 fts = channel slope0.032 ft/ftTd = permissible shear stress (temp 1)2.25lb/sf Option 1 LinerLining OKGrass-Lined/Straw LinerTd = permissible shear stress (temp 1)2.25lb/sf Temp Option 1Lining OKNAG SC150Td = permissible shear stress (temp 2)1.65lb/sf Temp Option 3Choose different liningStraw Mat/No vegetation
10/16/20Design Eng:11/11/20Checked By:Temp. Diversion CalloutMax. Contributing Drainage Area (ac)Diversion Length (ft) Upstream Elevation (ft)Downstream Elevation (ft)Slope (%)D-12.09 612 2077.55 2063 2.38%D-21.29 372 2070 2063 1.88%TD-30.76 267 2072 2066 2.25%TD-41.8 706 2071 2063 1.13%TD-51.09 250 2071 2066 2.00%TD-61.54 474 2071 2068 0.63%TD-70.31 222 2071 2068 1.35%Drainage Area:91040.40 2.09 acWeighted Runoff CoefficientLand Cover DescriptionC-ValueArea (ac)Percentage of Total AreaWeighted CBare Soil0.60 2.09 100.00% 0.60Max. Total Drainage Area: 2.09 Weighted C-Value:0.60Storm Event Rainfall Intensity-I (in/hr) Runoff (CFS)10-Year/24-Hour7.128.9325-Year/24-Hour8.1510.2250-Year/24-Hour8.9411.21*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 locationMin. Channel Slope:0.006 ft/ft*use for normal depthMax. Channel Slope:0.024 ft/ft*use for shear strengthRevision Date:MTPFerncliff RetStation Number:5574Original Date:JAPTemporary Diversions - Phase 2Estimated RunoffChannel Parameters
10/16/20Design Eng:11/11/20Checked By:Revision Date:MTPFerncliff RetStation Number:5574Original Date:JAPLining OptionsDescriptionPermissible Velocity (Vp)Manning n-Value:Natural Soil Sandy Silt Bare Soil2.00 0.025Natural Soil Silt Clay Bare Soil3.50 0.025Natural Soil Clay Bare Soil6.00 0.025Option 1 Grass-Lined/Straw Liner 7.000.033Temp Lining 1 NAG SC1508.00 0.035Temp Lining 2 Straw Mat/No vegetation7.00 0.035*values taken from tables and support information found on the Appendix tabBottom Width (B):1.00ftSide Slopes (M:1)2Max Depth of Channel:2.00ftPermissible Velocities - Vp - Perm Grass LiningManning n for clean, weathered channel
10/16/20Design Eng:11/11/20Checked By:Revision Date:MTPFerncliff RetStation Number:5574Original Date:JAPCross-Sectional Area 10.00 sfWetted Perimeter 9.94 ftHydraulic Radius 1.01 ftMax Allowed Velocity9.224ft/sBest Hydraulic Section Method (Channel with good maintenance)Cm=0.729k=0.472*Data taken from appendix tabCm[Qn/sqrt(S)]^(3/8)= y =0.98 ft11.73 inDepth is Okay*assumed grass lined channel for the 25-year/24-hour storm event with a Tc of 5-minutesNormal-Depth Procedure (Channel with no maintenance)MANNINGS N:0.033*conservative approachZ10 required: 2.486Z25 required: 2.845Z50 required: 3.121Z10 required: 1.282Z25 required: 1.468Z50 required: 1.610NORMAL DEPTH-y (ft) AREA-A (sf) WETTED PERIMETER-P (FT) HYD RADIUS-R (ft) Zav Z10 Comp Z25 Comp Z50 Comp Z10 Comp Z25 Comp Z50 Comp0.100.12 1.45 0.08 0.02 NARROW NARROW NARROW NARROW NARROW NARROW0.150.20 1.67 0.12 0.05 NARROW NARROW NARROW NARROW NARROW NARROW0.200.28 1.89 0.15 0.08 NARROW NARROW NARROW NARROW NARROW NARROW0.250.38 2.12 0.18 0.12 NARROW NARROW NARROW NARROW NARROW NARROW0.300.48 2.34 0.20 0.17 NARROW NARROW NARROW NARROW NARROW NARROW0.350.60 2.57 0.23 0.22 NARROW NARROW NARROW NARROW NARROW NARROW0.400.72 2.79 0.26 0.29 NARROW NARROW NARROW NARROW NARROW NARROW0.450.86 3.01 0.28 0.37 NARROW NARROW NARROW NARROW NARROW NARROW0.501.00 3.24 0.31 0.46 NARROW NARROW NARROW NARROW NARROW NARROW0.551.16 3.46 0.33 0.56 NARROW NARROW NARROW NARROW NARROW NARROW0.601.32 3.68 0.36 0.67 NARROW NARROW NARROW NARROW NARROW NARROW0.651.50 3.91 0.38 0.79 NARROW NARROW NARROW NARROW NARROW NARROW0.701.68 4.13 0.41 0.92 NARROW NARROW NARROW NARROW NARROW NARROW0.751.88 4.35 0.43 1.07 NARROW NARROW NARROW NARROW NARROW NARROW0.802.08 4.58 0.45 1.23 NARROW NARROW NARROW NARROW NARROW NARROWMax. Allowed Velocity in ChannelREMARKS BASED ON MIN SLOPE REMARKS BASED ON MAX SLOPEBased on Min. SlopeBased on Max. Slope
10/16/20Design Eng:11/11/20Checked By:Revision Date:MTPFerncliff RetStation Number:5574Original Date:JAP0.852.30 4.80 0.48 1.40 NARROW NARROW NARROW WIDE NARROW NARROW0.902.52 5.02 0.50 1.59 NARROW NARROW NARROW WIDE WIDE NARROW0.952.76 5.25 0.52 1.79 NARROW NARROW NARROW WIDE WIDE WIDE1.003.00 5.47 0.55 2.01 NARROW NARROW NARROW WIDE WIDE WIDE1.053.26 5.70 0.57 2.24 NARROW NARROW NARROW WIDE WIDE WIDE1.103.52 5.92 0.59 2.49 WIDE NARROW NARROW WIDE WIDE WIDE1.153.80 6.14 0.62 2.75 WIDE NARROW NARROW WIDE WIDE WIDE1.204.08 6.37 0.64 3.03 WIDE WIDE NARROW WIDE WIDE WIDE1.254.38 6.59 0.66 3.33 WIDE WIDE WIDE WIDE WIDE WIDE1.304.68 6.81 0.69 3.64 WIDE WIDE WIDE WIDE WIDE WIDE1.355.00 7.04 0.71 3.97 WIDE WIDE WIDE WIDE WIDE WIDE1.405.32 7.26 0.73 4.32 WIDE WIDE WIDE WIDE WIDE WIDE1.455.66 7.48 0.76 4.69 WIDE WIDE WIDE WIDE WIDE WIDE1.506.00 7.71 0.78 5.08 WIDE WIDE WIDE WIDE WIDE WIDE1.556.36 7.93 0.80 5.48 WIDE WIDE WIDE WIDE WIDE WIDE1.606.72 8.16 0.82 5.91 WIDE WIDE WIDE WIDE WIDE WIDE1.657.10 8.38 0.85 6.35 WIDE WIDE WIDE WIDE WIDE WIDE1.707.48 8.60 0.87 6.81 WIDE WIDE WIDE WIDE WIDE WIDE1.757.88 8.83 0.89 7.30 WIDE WIDE WIDE WIDE WIDE WIDE1.808.28 9.05 0.91 7.80 WIDE WIDE WIDE 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 InterpolationNormal Depth - y (ft)Zav1.102.75x2.845*25-year storm1.153.03x=1.12 ft13.40 in
10/16/20Design Eng:11/11/20Checked By:Revision Date:MTPFerncliff RetStation Number:5574Original Date:JAPVelocity Calculations based on Channel DimensionsV=[1.49*R^(2/3)S^(1/2)]/nLining OptionsDescriptionCalculated Velocity-V (fps)Velocity CheckNatural SoilSandy Silt Bare Soil6.75redesignNatural SoilSilt Clay Bare Soil6.75redesignNatural SoilClay Bare Soil6.75redesignOption 1Grass-Lined/Straw Liner5.11Velocity OKTemp Lining 1NAG SC1504.82Velocity OKTemp Lining 2Straw Mat/No vegetation4.82Velocity OKTractive Force CalculationsShear Stress at Normal DepthT=wds1.657 lb/sfw = unit weight of water62.4lb/cfd = flow depth1.12 fts = channel slope0.024 ft/ftTd = permissible shear stress (temp 1)2.25lb/sf Option 1 LinerLining OKGrass-Lined/Straw LinerTd = permissible shear stress (temp 1)2.25lb/sf Temp Option 1Lining OKNAG SC150Td = permissible shear stress (temp 2)1.65lb/sf Temp Option 3Choose different liningStraw Mat/No vegetation

Manufacturing Specifications

Tensar International Corporation warrants that at the time of delivery the product furnished
hereunder shall conform to the specification stated herein. Any other warranty including
merchantability and fitness for a particular purpose, are hereby executed. If the product
does not meet specifications on this page and Tensar is notified prior to installation, Tensar
will replace the product at no cost to the customer. This product specification supersedes
all prior specifications for the product described above and is not applicable to any
products shipped prior to January 1, 2012.
©2013, Tensar International Corporation
Tensar International Corporation
2500 Northwinds Parkway
Suite 500
Alpharetta, GA 30009
800-TENSAR-1
tensarcorp.com EC_RMX_MPDS_ESC150_6.13
DESCRIPTION
The extended-term double net erosion control blanket shall be a
machine-produced mat of 70% agricultural straw and 30% coconut
fiber with a functional longevity of up to 24 months. (NOTE: functional
longevity may vary depending upon climatic conditions, soil, geograph-
ical location, and elevation). The blanket shall be of consistent
thickness with the straw and coconut evenly distributed over the
entire area of the mat. The blanket shall be covered on the top side
with a heavyweight photodegradable polypropylene netting having
ultraviolet additives to delay breakdown and an approximate 0.63 x
0.63 in (1.59 x 1.59 cm) mesh, and on the bottom side with a light-
weight photodegradable polypropylene netting with an approximate
0.50 x 0.50 (1.27 x 1.27 cm) mesh. The blanket shall be sewn together
on 1.50 inch (3.81 cm) centers with degradable thread. The blanket shall
be manufactured with a colored thread stitched along both outer
edges (approximately 2-5 inches [5-12.5 cm] from the edge) as an
overlap guide for adjacent mats.
The SC150 shall meet Type 3.B specification requirements established
by the Erosion Control Technology Council (ECTC) and Federal Highway
Administration’s (FHWA) FP-03 Section 713.17
Material Content
Matrix 70% Straw Fiber
30% Coconut Fiber
0.35 lbs/sq yd (0.19 kg/sm)
0.15 lbs/sq yd (0.08 kg/sm)
Netting
Top: Heavyweight
photodegradable
with UV additives
Bottom: lighweight
photodegradable
3 lbs/1000 sq ft (1.47 kg/100 sm)
1.5 lb/1000 sq ft (0.73 kg/100 sm)
Thread Degradable
Standard Roll Sizes
Width 6.67 ft (2.03 m)8 ft (2.4 m)16.0 ft (4.87 m)
Length 108 ft (32.92 m)112 ft (34.14 m)108 ft (32.92 m)
Weight ± 10%44 lbs (19.95 kg)55 lbs (24.95 kg)105.6 lbs (47.9 kg)
Area 80 sq yd (66.9 sm)100 sq yd (83.61 sm)192 sq yd (165.6 sm)
Index Property Test Method Typical
Thickness ASTM D6525 0.35 in.
(8.89 mm)
Resiliency ECTC Guidelines 75%
Water Absorbency ASTM D1117 342%
Mass/Unit Area ASTM D6475 7.87 oz/sy
(267.6 g/sm)
Swell ECTC Guidelines 30%
Smolder Resistance ECTC Guidelines Yes
Stiffness ASTM D1388 1.11 oz-in
Light Penetration ASTM D6567 6.2%
Tensile Strength - MD ASTM D6818 362.4 lbs/ft
(5.37 kN/m)
Elongation - MD ASTM D6818 29.4%
Tensile Strength - TD ASTM D6818 136.8 lbs/ft
(2.03 kN/m)
Elongation - TD ASTM D6818 27.6%
Biomass Improvement ASTM D7322 481%
Design Permissible Shear Stress
Unvegetated Shear Stress 2.00 psf (96 Pa)
Unvegetated Velocity 8.0 fps (2.44 m/s)
Slope Design Data: C Factors
Slope Gradients (S)
Slope Length (L)≤ 3:1 3:1 – 2:1 ≥ 2:1
≤ 20 ft (6 m)0.001 0.048 0.100
20-50 ft 0.051 0.079 0.145
≥ 50 ft (15.2 m)0.10 0.110 0.190
NTPEP Large-Scale Slope ASTM D6459 - C-factor = 0.031
Roughness Coefficients – Unveg.
Flow Depth Manning’s n
≤ 0.50 ft (0.15 m)0.050
0.50 – 2.0 ft 0.050-0.018
≥ 2.0 ft (0.60 m)0.018
Specification Sheet – EroNet™ SC150 ® Erosion Control Blanket
DESCRIPTION
The permanent erosion control blanket shall be a machine-produced
mat of 100% UV stable polypropylene fiber. The matting shall be of
consistent thickness with the synthetic fibers evenly distributed over
the entire area of the mat. The matting shall be covered on the top
side with black heavyweight UV-stabilized polypropylene netting
having ultraviolet additives to delay breakdown and an approximate
0.50 x 0.50 inch (1.27 x 1.27 cm) mesh. The bottom net shall also be UV-
stabilized polypropylene with a 0.63 x 0.63 inch (1.57 x 1.57 cm) mesh
size. The blanket shall be sewn together on 1.5 inch (3.81 cm) centers
with non-degradable thread. All mats shall be manufactured with a
colored thread stitched along both outer edges as an overlap guide for
adjacent mats. The P300 shall meet Type 5A, 5B, specification
requirements established by the Erosion Control Technology Council
(ECTC) and Federal Highway Administration’s (FHWA) FP-03
Section 713.18
Material Content
Matrix 100% UV stable
Polypropylene Fiber
0.7 lbs/sq yd
(0.38 kg/sm)
Netting
Top: UV-stabilized Polypropylene
Bottom: UV-stabilized Polypropylene
5 lbs/1000 sq ft
(24.4 g/sm)
3 lbs/1000 sq ft
(14.7 g/sm)
Thread Polypropylene, UV stable
Standard Roll Sizes
Width 6.5 ft (2.0 m)8 ft (2.44 m)
Length 108 ft (32.92 m) 112 ft (35.14 m)
Weight ± 10%61 lbs (27.66 kg) 76.25 lbs (34.59 kg)
Area 80 sq yd (66.0 sm) 100 sq yd (83.61 sm)
Slope Design Data: C Factors
Slope Gradients (S)
Slope Length (L)≤ 3:1 3:1 – 2.1 ≥ 2:1
≤ 20 ft (6 m)0.001 0.029 0.082
20-50 ft 0.036 0.060 0.086
≥ 50 ft (15.2 m)0.070 0.090 0.110
Index Property Test Method Typical
Thickness ASTM D6525 0.47 in.
(11.94 mm)
Resiliency ASTM D6524 91.5%
Density ASTM D792 0.916 g/cm3
Mass/Unit Area ASTM 6566 13.03 oz/sy
(443 g/m2)
UV Stability ASTM D4355/
1000 hr 90%
Porosity ECTC Guidelines 95.89%
Stiffness ASTM D1388 0.94 in-lb
(1085378 mg-cm)
Light Penetration ASTM D6567 17.9%
Tensile Strength - MD ASTM D6567 438 lbs/ft
(6.49 kN/m)
Elongation - MD ASTM D6818 28.1%
Tensile Strength - TD ASTM D6818 291.9 lbs/ft
(4.32 kN/m)
Elongation - TD ASTM D6818 26.7%
Biomass Improvement ASTM D7322 497%
Design Permissible Shear Stress
Short Duration Long Duration
Phase 1: Unvegetated 3.0 psf (144 Pa)2.0 psf (96 Pa)
Phase 2: Partially Veg.8.0 psf (383 Pa)8.0 psf (383 Pa)
Phase 3: Fully Veg.8.0 psf (383 Pa)8.0 PSF (383 Pa)
Unvegetated Velocity 9.0 fps (2.7 m/s)
Vegetaged Velocity 16 fps (4.9 m/s)
Roughness Coefficients – Unveg.
Flow Depth Manning’s n
≤ 0.50 ft (0.15 m)0.034
0.50 – 2.0 ft 0.034-0.020
≥ 2.0 ft (0.60 m)0.020
Specification Sheet – EroNet™ P300 ® Permanent Erosion Control Blanket
Tensar International Corporation warrants that at the time of delivery the product furnished
hereunder shall conform to the specification stated herein. Any other warranty including
merchantability and fitness for a particular purpose, are hereby executed. If the product
does not meet specifications on this page and Tensar is notified prior to installation, Tensar
will replace the product at no cost to the customer. This product specification supersedes
all prior specifications for the product described above and is not applicable to any
products shipped prior to January 1, 2012.
©2013, Tensar International Corporation
Tensar International Corporation
2500 Northwinds Parkway
Suite 500
Alpharetta, GA 30009
800-TENSAR-1
tensarcorp.com EC_RMX_MPDS_P300_5.13