20181199 Ver 1_Stormwater Report_20181018

Professional Engineer: Peter Bellantoni, PE
NC License #033040
American Legion Post 6
Highway 54
Wake County, North Carolina
401 Providence Road
Suite 200
Chapel Hill, NC 27514
T: 919-929-1173
F: 919-493-6548
Firm License #: F-1267
GENERAL PROJECT DESCRIPTION AND
www.pennoni.com
SUPPLEMENTAL STORMWATER MANAGEMENT
RY-AW4111D_tIEel Z1i
Prepared By:
Pennoni
401 Providence Road, Suite 200
Chapel Hill, NC 27514
[phone]
Firm License: F-1267
Project #LCGR1608
June 8, 2018
Revised: July 27, 2018
Revised: October 17, 2018

Table of Contents
General Project Description / Stormwater Management........................................................ 3
General Project Description.............................................................................................................
3
StormwaterManagement...............................................................................................................
3
StormwaterConveyance..................................................................................................................
4
Stormwater Analysis Summary (Peak Flow)....................................................................................
4
SoilsMap........................................................................................................................................35
USGSMap......................................................................................................................................
36
NOAA Atlas 14 Precipitation Data..................................................................................................
40
Pointof Interest#1..........................................................................................................................44
Pre -development P0I#1, Time of Concentration "Tc" Calculations..............................................42
Post -development P0I#1 Time of Concentration "Tc" Calculations .............................................
43
Culvertdesign reports......................................................................................................................44
Post -Development Culvert Master Report (Entrance Culvert)......................................................45
Post -Development Culvert Master Report (Main Driveway).........................................................46
Stormwater Management Summary.................................................................................................47
Hydrograph Summary Report (1 -,2 -,25 --year storms)..................................................................
59
Stormwater Conveyance Summary...................................................................................................60
WetDetention Pond Calculations..................................................................................................64
Stormwater BMP Design Summary...................................................................................................65
Wet Detention Pond Calculations..................................................................................................
67
Rip -Rap Calculation..........................................................................................................................68
Wet Detention Pond Operation and Management Plan.....................................................................72
North American Green (Channel Analysis)........................................................................................87
DrainageArea Plans.........................................................................................................................91
Pre -Development Drainage Area Plan...............................................................................................
Post -Development Drainage Area Plan.............................................................................................

General Project Description/Stormwater Management
GENERAL PROJECT DESCRIPTION
American Legion proposes to develop a facility hall (Parcel Identification Number: 9749101791
and 9748194003) located on NC Highway 54, Town of Chapel Hill, Orange County North Carolina.
The proposed site will include the construction of a 15,713 square feet 1 -story facility hall,
parking lot, wet pond, and a gravel recreational vehicle parking. A stormwater pond will be
constructed; this pond is being designed as a site amenity and to provide a source for fire fighting
purposes; consequently it will be over -designed with regard to stormwater management
requirements. The proposed development will also include the construction of a landscaping,
lighting and the utilities necessary to support the development. Access to the site will be provided
by one (1) full access driveway —onto NC Highway 54. Pertinent data characterizing the existing
and proposed site conditions are shown on the accompanying Plans.
STORMWATER MANAGEMENT
The pre -development condition of the site consists of one (1) point of interest. The existing site
is located within the Haw River basin. POI#1 is the location where the proposed stormwater
Pond will discharge at the northerly portion of the site. The point of interest and drainage areas
have been depicted on the Pre- and Post -development Drainage Area Plans included in the
Appendix of this report. Hydrographs have been generated for the 1-, 2- and 25 -year storm
events.
The post development condition maintains the same point of interest. The development
proposes an increase in impervious surface coverage by approximately 98,981 SF (total site:
644,552 SF —15.3%). In order to provide water quality and rate control for POI#1, a wet detention
pond has been designed in accordance with the NCDEQ Stormwater BMP manual that provides
85% TSS, 30% TN and 40% TP removal rates. This facility has also been designed to reduce the
post -development peak flow rates for the 1-,2-, and 25 -year storm events to be at or below the
corresponding pre -development peak flow rates. Please refer to the pond report and
corresponding hydrographs for routed post -development POI#1 basin inflow.
The stormwater management analysis has been analyzed in accordance with the Orange
County's Stormwater Management Requirements (Section 6.14 of the UDO) and NCDENR
Stormwater BMP Manual requirements. The post -development conditions provide stormwater
runoff rate control to reduce the post- development peak flows rates for the 1-, 2-, and 25 -year
storm events to be at or below the corresponding pre -development peak flow rates.
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The USDA NRCS Hydrologic Urban Hydrology for Small Watersheds was utilized for calculating
the peak runoff rates and generating hydrographs for the pre -development and post -
development as defined in the computer watershed software "Hydraflow Hydrographs Extension
for AutoCAD Civil 3D 2015". The hydrographs were generated based upon the precipitation
amounts provided by NOAA Atlas 14 for each storm event.
STORMWATER CONVEYANCE
The storm drainage system was designed to intercept runoff at topographic low points and areas
of significant runoff quantities and convey the stormwater runoff to the proposed wet detention
facility. Along the main driveway, check dams are proposed every 200 feet inorder to provide
some level of detention time in which results to potential for some level of nuetrient removal.
They are placed to address water quality. StormCAD Version 8i has been utilized for designing
the stormwater conveyance system in accordance with the standard specifications and details.
Conveyance design precipitation amounts are based upon NOAA Atlas 14 storm event.
STORMWATER ANALYSIS SUMMARY (PEAK FLOW)
Peak Discharge Flowrates, Q (cfs)
Point of Interest: 130I#1
Storm
Event
r
Q @ POI (cfs)
Percent
Increase
Existing Proposed
1
2.442 0.122
-95%
2
5.402 0.168
-97%
25
23.05 0.317
-98.6%
Page 4 of 93

SOILS MAP
Page 5 of 93

USDA United States
Department of
Agriculture
N RCS
Natural
Resources
Conservation
Service
A product of the National
Cooperative Soil Survey,
a joint effort of the United
States Department of
Agriculture and other
Federal agencies, State
agencies including the
Agricultural Experiment
Stations, and local
participants
Custom Soil Resource
Report for
Orange County,
North Carolina
American Legion
Page 6ARR 4, 2018

Preface
Soil surveys contain information that affects land use planning in survey areas.
They highlight soil limitations that affect various land uses and provide information
about the properties of the soils in the survey areas. Soil surveys are designed for
many different users, including farmers, ranchers, foresters, agronomists, urban
planners, community officials, engineers, developers, builders, and home buyers.
Also, conservationists, teachers, students, and specialists in recreation, waste
disposal, and pollution control can use the surveys to help them understand,
protect, or enhance the environment.
Various land use regulations of Federal, State, and local governments may impose
special restrictions on land use or land treatment. Soil surveys identify soil
properties that are used in making various land use or land treatment decisions.
The information is intended to help the land users identify and reduce the effects of
soil limitations on various land uses. The landowner or user is responsible for
identifying and complying with existing laws and regulations.
Although soil survey information can be used for general farm, local, and wider area
planning, onsite investigation is needed to supplement this information in some
cases. Examples include soil quality assessments (http://www.nres.usda.gov/wps/
portal/nres/main/soils/health/) and certain conservation and engineering
applications. For more detailed information, contact your local USDA Service Center
(https://offices.sc.egov.usda.gov/locator/app?agency=nres) or your NRCS State Soil
Scientist (http://www.nres.usda.gov/wps/portal/nres/detail/soils/contactus/?
cid=nres142p2_053951).
Great differences in soil properties can occur within short distances. Some soils are
seasonally wet or subject to flooding. Some are too unstable to be used as a
foundation for buildings or roads. Clayey or wet soils are poorly suited to use as
septic tank absorption fields. A high water table makes a soil poorly suited to
basements or underground installations.
The National Cooperative Soil Survey is a joint effort of the United States
Department of Agriculture and other Federal agencies, State agencies including the
Agricultural Experiment Stations, and local agencies. The Natural Resources
Conservation Service (NRCS) has leadership for the Federal part of the National
Cooperative Soil Survey.
Information about soils is updated periodically. Updated information is available
through the NRCS Web Soil Survey, the site for official soil survey information.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its
programs and activities on the basis of race, color, national origin, age, disability,
and where applicable, sex, marital status, familial status, parental status, religion,
sexual orientation, genetic information, political beliefs, reprisal, or because all or a
part of an individual's income is derived from any public assistance program. (Not
all prohibited bases apply to all programs.) Persons with disabilities who require
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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.
Page 8 of 93

Contents
Preface.................................................................................................... .
How Soil Surveys Are Made...................................................................
SoilMap....................................................................................................
SoilMap.................................................................................................
Legend...................................................................................................
MapUnit Legend...................................................................................
Map Unit Descriptions............................................................................
Orange County, North Carolina..........................................................
ApB—Appling sandy loam, 2 to 6 percent slopes ..........................
ApC—Appling sandy loam, 6 to 10 percent slopes ........................
Ch—Chewacla loam, 0 to 2 percent slopes, frequently flooded.....
Cp—Congaree fine sandy loam, 0 to 2 percent slopes, frequently
flooded.....................................................................................
GeB—Georgeville silt loam, 2 to 6 percent slopes .........................
GeC—Georgeville silt loam, 6 to 10 percent slopes .......................
HeB—Helena sandy loam, 2 to 8 percent slopes ...........................
HhA—Helena-Sedgefield complex, 0 to 2 percent slopes ..............
HrB—Herndon silt loam, 2 to 6 percent slopes ..............................
HrC—Herndon silt loam, 6 to 10 percent slopes ............................
TaD—Tarrus silt loam, 8 to 15 percent slopes ................................
W—Water
References........
.2
.5
.8
..9
10
11
11
14
14
15
16
17
19
20
21
23
25
26
27
29
30
Page 9 of 93

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
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Custom Soil Resource Report
scientists classified and named the soils in the survey area, they compared the
individual soils with similar soils in the same taxonomic class in other areas so that
they could confirm data and assemble additional data based on experience and
research.
The objective of soil mapping is not to delineate pure map unit components; the
objective is to separate the landscape into landforms or landform segments that
have similar use and management requirements. Each map unit is defined by a
unique combination of soil components and/or miscellaneous areas in predictable
proportions. Some components may be highly contrasting to the other components
of the map unit. The presence of minor components in a map unit in no way
diminishes the usefulness or accuracy of the data. The delineation of such
landforms and landform segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, onsite
investigation is needed to define and locate the soils and miscellaneous areas.
Soil scientists make many field observations in the process of producing a soil map.
The frequency of observation is dependent upon several factors, including scale of
mapping, intensity of mapping, design of map units, complexity of the landscape,
and experience of the soil scientist. Observations are made to test and refine the
soil -landscape model and predictions and to verify the classification of the soils at
specific locations. Once the soil -landscape model is refined, a significantly smaller
number of measurements of individual soil properties are made and recorded.
These measurements may include field measurements, such as those for color,
depth to bedrock, and texture, and laboratory measurements, such as those for
content of sand, silt, clay, salt, and other components. Properties of each soil
typically vary from one point to another across the landscape.
Observations for map unit components are aggregated to develop ranges of
characteristics for the components. The aggregated values are presented. Direct
measurements do not exist for every property presented for every map unit
component. Values for some properties are estimated from combinations of other
properties.
While a soil survey is in progress, samples of some of the soils in the area generally
are collected for laboratory analyses and for engineering tests. Soil scientists
interpret the data from these analyses and tests as well as the field -observed
characteristics and the soil properties to determine the expected behavior of the
soils under different uses. Interpretations for all of the soils are field tested through
observation of the soils in different uses and under different levels of management.
Some interpretations are modified to fit local conditions, and some new
interpretations are developed to meet local needs. Data are assembled from other
sources, such as research information, production records, and field experience of
specialists. For example, data on crop yields under defined levels of management
are assembled from farm records and from field or plot experiments on the same
kinds of soil.
Predictions about soil behavior are based not only on soil properties but also on
such variables as climate and biological activity. Soil conditions are predictable over
long periods of time, but they are not predictable from year to year. For example,
soil scientists can predict with a fairly high degree of accuracy that a given soil will
have a high water table within certain depths in most years, but they cannot predict
that a high water table will always be at a specific level in the soil on a specific date.
After soil scientists located and identified the significant natural bodies of soil in the
survey area, they drew the boundaries of these bodies on aerial photographs and
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Custom Soil Resource Report
identified each as a specific map unit. Aerial photographs show trees, buildings,
fields, roads, and rivers, all of which help in locating boundaries accurately.
Page 12 of 93

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.
Page 13 of 93

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MAP LEGEND
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Spoil Area
The soil surveys that comprise your AOI were mapped at
Soil Map Unit Polygons
rwr
Soil Map Unit Lines
0
Soil Map Unit Points
Special
Point Features
{J
Blowout
Borrow Pit
measurements.
Clay Spot
Wet Spot
Closed Depression
.A
Gravel Pit
.4
Gravelly Spot
0
Landfill
.-
Lava Flow
Coordinate System: Web Mercator (EPSG:3857)
Marsh or swamp
+
Mine or Quarry
Streams and Canals
Miscellaneous Water
Perennial Water
IV
Rock Outcrop
distance and area. A projection that preserves area, such as the
Saline Spot
d
Sandy Spot
Severely Eroded Spot
accurate calculations of distance or area are required.
Sinkhole
Interstate Highways
Slide or Slip
of
Sodic Spot
Custom Soil Resource Report
MAP INFORMATION
Date(s) aerial images were photographed: Apr 4, 2014—Feb 4,
2017
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.
Page 15 of 93
Spoil Area
The soil surveys that comprise your AOI were mapped at
1:20,000.
Stony Spot
Very Stony Spot
Please rely on the bar scale on each map sheet for map
measurements.
Wet Spot
.A
Other
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
.-
Special Line Features
Coordinate System: Web Mercator (EPSG:3857)
Water Features
Streams and Canals
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
Transportation
distance and area. A projection that preserves area, such as the
#_F_+
Rails
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
r•,,r
Interstate Highways
US Routes
This product is generated from the USDA-NRCS certified data as
Major Roads
of the version date(s) listed below.
Local Roads
Soil Survey Area: Orange County, North Carolina
Background
Survey Area Data: Version 17, Oct 2, 2017
lW
Aerial Photography
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Apr 4, 2014—Feb 4,
2017
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.
Page 15 of 93

Custom Soil Resource Report
Map Unit Legend
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.
Page 16 of 93
Map Unit Symbol
Map Unit Name
Acres in AOI
Percent of AOI
ApB
Appling sandy loam, 2 to 6
519.7
43.9%
percent slopes
Appling sandy loam, 6 to 10
ApC
183.2
15.5%
percent slopes
Ch
Chewacla loam, 0 to 2 percent
15.3
1.3%
slopes, frequently flooded
Cp
Congaree fine sandy loam, 0 to
30.0
2.5%
2 percent slopes, frequently
flooded
GeB
Georgeville silt loam, 2 to 6
124.6
10.5%
percent slopes
GeC
Georgeville silt loam, 6 to 10
81.1
6.8%
percent slopes
Helena sandy loam, 2 to 8
10.3%
HeB
121.6
percent slopes
HhA
Helena -Sedgefield complex, 0
35.1
3.0%
to 2 percent slopes
HrB
Herndon silt loam, 2 to 6
28.6
2.4%
percent slopes
HrC
Herndon silt loam, 6 to 10
27.9
2.4%
percent slopes
TaD
Tarrus silt loam, 8 to 15 percent
15.0
1.3%
slopes
W
Water
2.7
0.2%
Totals for Area of Interest
1,184.7
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.
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Custom Soil Resource Report
Most minor soils have properties similar to those of the dominant soil or soils in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
management. These are called contrasting, or dissimilar, components. They
generally are in small areas and could not be mapped separately because of the
scale used. Some small areas of strongly contrasting soils or miscellaneous areas
are identified by a special symbol on the maps. If included in the database for a
given area, the contrasting minor components are identified in the map unit
descriptions along with some characteristics of each. A few areas of minor
components may not have been observed, and consequently they are not
mentioned in the descriptions, especially where the pattern was so complex that it
was impractical to make enough observations to identify all the soils and
miscellaneous areas on the landscape.
The presence of minor components in a map unit in no way diminishes the
usefulness or accuracy of the data. The objective of mapping is not to delineate
pure taxonomic classes but rather to separate the landscape into 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
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Custom Soil Resource Report
of the soils or miscellaneous areas in a mapped area are not uniform. An area can
be made up of only one of the major soils or miscellaneous areas, or it can be made
up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include miscellaneous areas. Such areas have little or no soil
material and support little or no vegetation. Rock outcrop is an example.
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Custom Soil Resource Report
Orange County, North Carolina
ApB—Appling sandy loam, 2 to 6 percent slopes
Map Unit Setting
National map unit symbol: 2vy6t
Elevation: 70 to 1,310 feet
Mean annual precipitation: 39 to 47 inches
Mean annual air temperature: 55 to 63 degrees F
Frost -free period: 200 to 250 days
Farmland classification: All areas are prime farmland
Map Unit Composition
Appling and similar soils: 92 percent
Minor components: 8 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Appling
Setting
Landform: Interfluves
Landform position (two-dimensional): Summit, shoulder
Landform position (three-dimensional): Interfluve
Down-slope shape: Convex
Across -slope shape: Convex
Parent material: Residuum weathered from igneous and metamorphic rock
Typical profile
Ap - 0 to 6 inches: sandy loam
BE - 6 to 10 inches: sandy loam
Bt - 10 to 39 inches: clay
BC - 39 to 46 inches: sandy clay loam
C - 46 to 80 inches: sandy clay loam
Properties and qualities
Slope: 2 to 6 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to
high (0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water storage in profile: Moderate (about 7.9 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 2e
Hydrologic Soil Group: B
Hydric soil rating: No
Minor Components
Helena
Percent of map unit: 8 percent
Landform: Interfluves
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Custom Soil Resource Report
Landform position (two-dimensional): Summit, shoulder
Landform position (three-dimensional): Interfluve
Down-slope shape: Convex
Across -slope shape: Convex
Hydric soil rating: No
ApC—Appling sandy loam, 6 to 10 percent slopes
Map Unit Setting
National map unit symbol: 3tgc
Elevation: 200 to 1,400 feet
Mean annual precipitation: 37 to 60 inches
Mean annual air temperature: 59 to 66 degrees F
Frost -free period: 200 to 240 days
Farmland classification: Farmland of statewide importance
Map Unit Composition
Appling and similar soils: 90 percent
Minor components: 2 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Appling
Setting
Landform: Hillslopes on ridges
Landform position (two-dimensional): Backslope
Landform position (three-dimensional): Side slope
Down-slope shape: Linear
Across -slope shape: Convex
Parent material: Saprolite derived from granite and gneiss and/or schist
Typical profile
Ap - 0 to 6 inches: sandy loam
Bt1 - 6 to 18 inches: sandy clay loam
Bt2 - 18 to 36 inches: clay
BC - 36 to 52 inches: sandy clay loam
C - 52 to 80 inches: sandy loam
Properties and qualities
Slope: 6 to 10 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to
high (0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water storage in profile: Moderate (about 8.5 inches)
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Custom Soil Resource Report
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: B
Hydric soil rating: No
Minor Components
Vance
Percent of map unit: 1 percent
Landform: Hillslopes on ridges
Landform position (two-dimensional): Backslope
Landform position (three-dimensional): Side slope
Down-slope shape: Linear
Across -slope shape: Convex
Hydric soil rating: No
Helena
Percent of map unit: 1 percent
Landform: Hillslopes on ridges
Landform position (two-dimensional): Shoulder, backslope
Landform position (three-dimensional): Side slope
Down-slope shape: Concave
Across -slope shape: Concave, convex
Hydric soil rating: No
Ch—Chewacla loam, 0 to 2 percent slopes, frequently flooded
Map Unit Setting
National map unit symbol: 2vy6r
Elevation: 330 to 660 feet
Mean annual precipitation: 39 to 47 inches
Mean annual air temperature: 55 to 63 degrees F
Frost -free period: 200 to 250 days
Farmland classification: Prime farmland if drained and either protected from flooding
or not frequently flooded during the growing season
Map Unit Composition
Chewacla, frequently flooded, and similar soils: 90 percent
Minor components: 10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Chewacla, Frequently Flooded
Setting
Landform: Flood plains
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Tread, talf
Down-slope shape: Linear
Across -slope shape: Linear
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Custom Soil Resource Report
Parent material: Loamy alluvium derived from igneous and metamorphic rock
Typical profile
Ap - 0 to 6 inches: loam
Bw - 6 to 52 inches: sandy clay loam
Cg - 52 to 80 inches: stratified sandy loam
Properties and qualities
Slope: 0 to 2 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Somewhat poorly drained
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to
high (0.20 to 2.00 in/hr)
Depth to water table: About 6 to 24 inches
Frequency of flooding: Frequent
Frequency of ponding: None
Available water storage in profile: Moderate (about 7.6 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 4w
Hydrologic Soil Group: B/D
Hydric soil rating: No
Minor Components
Wehadkee, frequently flooded
Percent of map unit: 5 percent
Landform: Flood plains
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Tread, talf
Down-slope shape: Linear
Across -slope shape: Linear
Hydric soil rating: Yes
Riverview, frequently flooded
Percent of map unit: 5 percent
Landform: Flood plains
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Tread, talf
Down-slope shape: Linear
Across -slope shape: Linear
Hydric soil rating: No
Cp—Congaree fine sandy loam, 0 to 2 percent slopes, frequently
flooded
Map Unit Setting
National map unit symbol: 2n86d
Elevation: 200 to 1,400 feet
Mean annual precipitation: 37 to 60 inches
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Custom Soil Resource Report
Mean annual air temperature: 59 to 66 degrees F
Frost -free period: 200 to 240 days
Farmland classification: Prime farmland if protected from flooding or not frequently
flooded during the growing season
Map Unit Composition
Congaree and similar soils: 80 percent
Minor components: 10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Congaree
Setting
Landform: Flood plains
Down-slope shape: Linear
Across -slope shape: Linear
Parent material: Loamy alluvium derived from igneous and metamorphic rock
Typical profile
Ap - 0 to 10 inches: fine sandy loam
C1 - 10 to 40 inches: loam
C2 - 40 to 80 inches: loamy fine sand
Properties and qualities
Slope: 0 to 2 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Moderately 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: About 30 to 48 inches
Frequency of flooding: Frequent
Frequency of ponding: None
Available water storage in profile: Moderate (about 8.0 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 3w
Hydrologic Soil Group: C
Hydric soil rating: No
Minor Components
Chewacla
Percent of map unit: 8 percent
Landform: Flood plains
Down-slope shape: Concave
Across -slope shape: Linear
Hydric soil rating: No
Wehadkee, undrained
Percent of map unit: 2 percent
Landform: Depressions on flood plains
Down-slope shape: Concave
Across -slope shape: Linear
Hydric soil rating: Yes
Page 23 of 93

Custom Soil Resource Report
GeB—Georgeville silt loam, 2 to 6 percent slopes
Map Unit Setting
National map unit symbol: 2vy6v
Elevation: 160 to 820 feet
Mean annual precipitation: 43 to 47 inches
Mean annual air temperature: 57 to 61 degrees F
Frost -free period: 200 to 230 days
Farmland classification: All areas are prime farmland
Map Unit Composition
Georgeville and similar soils: 90 percent
Minor components: 10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Georgeville
Setting
Landform: I nterfluves
Landform position (two-dimensional): Summit, shoulder
Landform position (three-dimensional): Interfluve
Down-slope shape: Convex
Across -slope shape: Convex
Parent material: Residuum weathered from metavolcanics and/or residuum
weathered from argillite and/or residuum weathered from phyllite and/or
residuum weathered from sericite schist
Typical profile
Ap - 0 to 9 inches: silt loam
E - 9 to 14 inches: silt loam
Bt1 - 14 to 20 inches:
silty clay loam
Bt2 - 20 to 27 inches:
clay
Bt3 - 27 to 49 inches:
silty clay
BCt - 49 to 57 inches:
silty clay loam
C - 57 to 62 inches: silt
loam
Properties and qualities
Slope: 2 to 6 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to
high (0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water storage in profile: Moderate (about 9.0 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 2e
Page 24 of 93

Custom Soil Resource Report
Hydrologic Soil Group: B
Hydric soil rating: No
Minor Components
Tarrus
Percent of map unit: 10 percent
Landform: Interfluves
Landform position (two-dimensional): Summit, shoulder
Landform position (three-dimensional): Interfluve
Down-slope shape: Convex
Across -slope shape: Convex
Hydric soil rating: No
GeC—Georgeville silt loam, 6 to 10 percent slopes
Map Unit Setting
National map unit symbol: 2vy6n
Elevation: 160 to 820 feet
Mean annual precipitation: 43 to 47 inches
Mean annual air temperature: 57 to 61 degrees F
Frost -free period: 200 to 230 days
Farmland classification: Farmland of statewide importance
Map Unit Composition
Georgeville and similar soils: 90 percent
Minor components: 10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Georgeville
Setting
Landform: Hillslopes
Landform position (two-dimensional): Backslope, shoulder
Landform position (three-dimensional): Side slope
Down-slope shape: Convex
Across -slope shape: Convex
Parent material: Residuum weathered from metavolcanics and/or residuum
weathered from argillite and/or residuum weathered from phyllite and/or
residuum weathered from sericite schist
Typical profile
Ap - 0 to 7 inches: silt loam
BE - 7 to 10 inches: silty clay loam
Bt - 10 to 44 inches: clay
BC - 44 to 53 inches: silty clay loam
C - 53 to 80 inches: loam
Properties and qualities
Slope: 6 to 10 percent
Depth to restrictive feature: More than 80 inches
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Custom Soil Resource Report
Natural drainage class: Well drained
Capacity of the most limiting layer to transmit water (Ksat):
high (0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water storage in profile: High (about 9.2 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: B
Hydric soil rating: No
Minor Components
Tarrus
Percent of map unit: 10 percent
Landform: Interfluves
Landform position (two-dimensional): Shoulder, backslope
Landform position (three-dimensional): Interfluve
Down-slope shape: Convex
Across -slope shape: Convex
Hydric soil rating: No
HeB—Helena sandy loam, 2 to 8 percent slopes
Map Unit Setting
National map unit symbol: 3tgt
Elevation: 200 to 1,400 feet
Mean annual precipitation: 37 to 60 inches
Mean annual air temperature: 59 to 66 degrees F
Frost -free period: 200 to 240 days
Farmland classification: All areas are prime farmland
Moderately high to
Map Unit Composition
Helena and similar soils: 90 percent
Minor components: 8 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Helena
Setting
Landform: Ridges
Landform position (two-dimensional): Summit, footslope
Down-slope shape: Concave
Across -slope shape: Concave
Parent material: Saprolite derived from granite and gneiss and/or schist
Typical profile
Ap - 0 to 8 inches: sandy loam
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Custom Soil Resource Report
E - 8 to 12 inches: sandy loam
Bt - 12 to 39 inches: clay
BC - 39 to 46 inches: clay loam
C - 46 to 80 inches: coarse sandy loam
Properties and qualities
Slope: 2 to 8 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Moderately well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat): Moderately low to
moderately high (0.06 to 0.20 in/hr)
Depth to water table: About 18 to 30 inches
Frequency of flooding: None
Frequency of ponding: None
Available water storage in profile: Moderate (about 7.6 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 2e
Hydrologic Soil Group: D
Hydric soil rating: No
Minor Components
Vance
Percent of map unit: 5 percent
Landform: Interfluves
Landform position (two-dimensional): Summit
Landform position (three-dimensional): Interfluve
Down-slope shape: Convex
Across -slope shape: Convex
Hydric soil rating: No
Wedowee
Percent of map unit: 3 percent
Landform: Interfluves
Landform position (two-dimensional): Summit
Landform position (three-dimensional): Interfluve
Down-slope shape: Convex
Across -slope shape: Convex
Hydric soil rating: No
Worsham, undrained
Percent of map unit: 0 percent
Landform: Depressions
Landform position (two-dimensional): Footslope
Down-slope shape: Concave
Across -slope shape: Concave
Hydric soil rating: Yes
Page 27 of 93

Custom Soil Resource Report
HhA—Helena-Sedgefield complex, 0 to 2 percent slopes
Map Unit Setting
National map unit symbol: 2n86g
Elevation: 200 to 1,400 feet
Mean annual precipitation: 37 to 60 inches
Mean annual air temperature: 59 to 66 degrees F
Frost -free period: 200 to 240 days
Farmland classification: All areas are prime farmland
Map Unit Composition
Helena and similar soils: 45 percent
Sedgefield and similar soils: 40 percent
Minor components: 4 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Helena
Setting
Landform: Ridges
Landform position (two-dimensional): Summit, footslope
Down-slope shape: Concave
Across -slope shape: Concave
Parent material: Saprolite derived from granite and gneiss and/or schist
Typical profile
Ap - 0 to 13 inches: sandy loam
Bt - 13 to 30 inches: clay
BC - 30 to 44 inches: fine sandy loam
C - 44 to 80 inches: sandy loam
Properties and qualities
Slope: 0 to 2 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Moderately well drained
Runoff class: Low
Capacity of the most limiting layer to transmit water (Ksat): Moderately low to
moderately high (0.06 to 0.20 in/hr)
Depth to water table: About 18 to 30 inches
Frequency of flooding: None
Frequency of ponding: None
Available water storage in profile: Moderate (about 7.4 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 2w
Hydrologic Soil Group: D
Hydric soil rating: No
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Custom Soil Resource Report
Description of Sedgefield
Setting
Landform: Ridges
Landform position (two-dimensional): Summit, footslope
Down-slope shape: Concave
Across -slope shape: Concave
Parent material: Saprolite derived from diorite and/or gabbro and/or diabase
and/or gneiss
Typical profile
Ap - 0 to 13 inches: sandy loam
Bt - 13 to 33 inches: clay
BC - 33 to 37 inches: sandy clay loam
C - 37 to 80 inches: sandy clay loam
Properties and qualities
Slope: 0 to 2 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Moderately well drained
Runoff class: Very high
Capacity of the most limiting layer to transmit water (Ksat):
moderately high (0.06 to 0.20 in/hr)
Depth to water table: About 12 to 18 inches
Frequency of flooding: None
Frequency of ponding: None
Available water storage in profile: High (about 9.6 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 2w
Hydrologic Soil Group: C/D
Hydric soil rating: No
Minor Components
Worsham, undrained
Percent of map unit: 2 percent
Landform: Depressions
Landform position (two-dimensional): Footslope
Down-slope shape: Concave
Across -slope shape: Concave
Hydric soil rating: Yes
Wehadkee, undrained
Percent of map unit: 2 percent
Landform: Depressions on flood plains
Down-slope shape: Concave
Across -slope shape: Linear
Hydric soil rating: Yes
Moderately low to
Page 29 of 93

Custom Soil Resource Report
HrB—Herndon silt loam, 2 to 6 percent slopes
Map Unit Setting
National map unit symbol: 2rkjn
Elevation: 70 to 980 feet
Mean annual precipitation: 39 to 47 inches
Mean annual air temperature: 55 to 63 degrees F
Frost -free period: 200 to 250 days
Farmland classification: All areas are prime farmland
Map Unit Composition
Herndon and similar soils: 90 percent
Minor components: 10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Herndon
Setting
Landform: I nterfluves
Landform position (two-dimensional): Summit
Landform position (three-dimensional): Interfluve
Down-slope shape: Convex
Across -slope shape: Convex
Parent material: Residuum weathered from phyllite
Typical profile
Ap - 0 to 8 inches: silt loam
Bt1 - 8 to 12 inches: silty clay loam
Bt2 - 12 to 44 inches: clay
C - 44 to 80 inches: silt loam
Properties and qualities
Slope: 2 to 6 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to
high (0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0
mmhos/cm)
Available water storage in profile: Moderate (about 8.9 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 2e
Hydrologic Soil Group: B
Hydric soil rating: No
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Custom Soil Resource Report
Minor Components
Lignum
Percent of map unit: 5 percent
Landform: Interfluves
Landform position (two-dimensional):
Landform position (three-dimensional).
Down-slope shape: Convex
Across -slope shape: Convex
Hydric soil rating: No
Nanford
Percent of map unit: 5 percent
Landform: Interfluves
Landform position (two-dimensional):
Landform position (three-dimensional).
Down-slope shape: Convex
Across -slope shape: Convex
Hydric soil rating: No
Summit, shoulder
Interfluve
Summit, shoulder
Interfluve
HrC—Herndon silt loam, 6 to 10 percent slopes
Map Unit Setting
National map unit symbol: 3tgx
Elevation: 300 to 700 feet
Mean annual precipitation: 37 to 60 inches
Mean annual air temperature: 59 to 66 degrees F
Frost -free period: 200 to 240 days
Farmland classification: Farmland of statewide importance
Map Unit Composition
Herndon and similar soils: 80 percent
Minor components: 5 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Herndon
Setting
Landform: Hillslopes on ridges
Landform position (two-dimensional): Summit, shoulder
Landform position (three-dimensional): Side slope
Down-slope shape: Linear
Across -slope shape: Convex
Parent material: Residuum weathered from metavolcanics and/or argillite
Typical profile
Ap - 0 to 3 inches: silt loam
E - 3 to 9 inches: silt loam
Bt1 - 9 to 14 inches: silty clay loam
Bt2 - 14 to 34 inches: silty clay
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Custom Soil Resource Report
BC - 34 to 48 inches: silty clay loam
C - 48 to 80 inches: silt loam
Properties and qualities
Slope: 6 to 10 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to
high (0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water storage in profile: Moderate (about 7.4 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: B
Hydric soil rating: No
Minor Components
Nanford
Percent of map unit: 5 percent
Landform: Hillslopes on ridges
Landform position (two-dimensional): Summit, shoulder
Landform position (three-dimensional): Side slope
Down-slope shape: Linear
Across -slope shape: Convex
Hydric soil rating: No
TaD—Tarrus silt loam, 8 to 15 percent slopes
Map Unit Setting
National map unit symbol: 2n868
Elevation: 200 to 650 feet
Mean annual precipitation: 37 to 60 inches
Mean annual air temperature: 59 to 66 degrees F
Frost -free period: 200 to 240 days
Farmland classification: Farmland of statewide importance
Map Unit Composition
Tarrus and similar soils: 75 percent
Minor components: 20 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Tarrus
Setting
Landform: Hillslopes on ridges
Page 32 of 93

Custom Soil Resource Report
Landform position (two-dimensional): Backslope
Landform position (three-dimensional): Side slope
Down-slope shape: Linear
Across -slope shape: Convex
Parent material: Residuum weathered from metavolcanics and/or argillite
Typical profile
Ap - 0 to 8 inches: silt loam
Bt - 8 to 50 inches: clay loam
Cr - 50 to 80 inches: weathered bedrock
Properties and qualities
Slope: 8 to 15 percent
Depth to restrictive feature: 40 to 60 inches to paralithic bedrock
Natural drainage class: Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat): Very low to high (0.00
to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water storage in profile: Moderate (about 7.7 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: B
Hydric soil rating: No
Minor Components
Badin
Percent of map unit: 15 percent
Landform: Hillslopes on ridges
Landform position (two-dimensional): Shoulder, backslope
Landform position (three-dimensional): Side slope
Down-slope shape: Linear
Across -slope shape: Convex
Hydric soil rating: No
Goldston
Percent of map unit: 5 percent
Landform: Hillslopes on ridges
Landform position (two-dimensional): Backslope
Landform position (three-dimensional): Side slope
Down-slope shape: Linear
Across -slope shape: Convex
Hydric soil rating: No
Page 33 of 93

Custom Soil Resource Report
W—Water
Map Unit Composition
Water: 100 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Water
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 8w
Hydric soil rating: No
Page 34 of 93

References
American Association of State Highway and Transportation Officials (AASHTO).
2004. Standard specifications for transportation materials and methods of sampling
and testing. 24th edition.
American Society for Testing and Materials (ASTM). 2005. Standard classification of
soils for engineering purposes. ASTM Standard D2487-00.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of
wetlands and deep -water habitats of the United States. U.S. Fish and Wildlife
Service FWS/OBS-79/31.
Federal Register. July 13, 1994. Changes in hydric soils of the United States.
Federal Register. September 18, 2002. Hydric soils of the United States.
Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric
soils in the United States.
National Research Council. 1995. Wetlands: Characteristics and boundaries.
Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service.
U.S. Department of Agriculture Handbook 18. http://www.nres.usda.gov/wps/portal/
nres/detail/national/soils/?cid=nres 142p2_054262
Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for
making and interpreting soil surveys. 2nd edition. Natural Resources Conservation
Service, U.S. Department of Agriculture Handbook 436. http://
www.nres.usda.gov/wps/portal/nres/detail/national/soils/?cid=nres142p2_053577
Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of
Agriculture, Natural Resources Conservation Service. http://
www. nres.usda.gov/wps/portal/nres/detail/national/soils/?cid=nres142p2_053580
Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and
Delaware Department of Natural Resources and Environmental Control, Wetlands
Section.
United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of
Engineers wetlands delineation manual. Waterways Experiment Station Technical
Report Y-87-1.
United States Department of Agriculture, Natural Resources Conservation Service.
National forestry manual. http://www.nres.usda.gov/wps/portal/nres/detail/soils/
home/?cid=nres142p2_053374
United States Department of Agriculture, Natural Resources Conservation Service.
National range and pasture handbook. http://www.nres.usda.gov/wps/portal/nres/
detail/national/landuse/rangepasture/?cid=stelprdb1043084
Page 35 of 93

Custom Soil Resource Report
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430 -VI. http://www.nres.usda.gov/wps/portal/
nres/detail/soils/scientists/?cid=nres142p2_054242
United States Department of Agriculture, Natural Resources Conservation Service.
2006. Land resource regions and major land resource areas of the United States,
the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook
296. http://www.nres.usda.gov/wps/portal/nres/detail/national/soils/?
cid=nres142p2_053624
United States Department of Agriculture, Soil Conservation Service. 1961. Land
capability classification. U.S. Department of Agriculture Handbook 210. http://
www.nrcs.usda.gov/lnternet/FSE—DOCUMENTS/nrcsl 42p2_052290.pdf
Page 36 of 93

USGS MAP
Page 37 of 93

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Page 38 of 93
7]
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N OAA
Page 39 of 93

4/24/2018
Precipitation Frequency Data Server
NOAA Atlas 14, Volume 2, Version 3
' Location name: Chapel Hill, North Carolina, USA*
Latitude: 35.924*, Longitude: -79.1995°
. Elevation: 490.67 ft**
source: ESRI Maps
** source: USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring, Maryland
PF tabular I PF graphical I Maps & aerials
PF tabular
11 PDS -based point precipitation frequency estimates with 90% confidence intervals (in inches/hour)' 11
Average recurrence interval (years)
Duration
00 5
5 -min 4.90 5.80 6.72
(4.48-5.36) (5.32-6.35) (6.14-7.34)
10 -min 3.91 4.64 5.38
-----]F--6.-43--]F--6.-78--]F--7.-09--]F--7---]F-7.60 7.76
(3.58-4.28) (4.25-5.08) (4.92-5.88) (5.38-6.43) (5.83-7.01) (6.14-7.40) (6.39-7.74) (6.58-8.02) (6.74-8.30) (6.83-8.48)
15 -min 3.26 3.89 4.54
(2.98-3.57) (3.56-4.25) (4.15-4.96)
30 -min 2.23 2.68 3.22
(2.04-2.44) (2.46-2.94) (2.95-3.52)
10
25
50
100 200 500 1000
7.37
8.06
8.52
8.93 9.26 9.61 9.85
(6.72-8.04)
(7.32-8.80)
(7.70-9.29)
(8.04-9.74) (8.29-10.1) (8.53-10.5) (8.68-10.8)
4.96
11
5.43
5.72
5.98
6.17
6.38
6.49
(4.53-5.42)
(4.93-5.92)
(1.90-2.34)
(5.38-6.52)
(5.53-6.74)
(5.66-6.97)
(5.71-7.10)
3.60
4.02
4.31
4.58
4.80
5.07
5.26
(3.28-3.93)
(3.65-4.39)
(1.63-2.05)
(4.12-4.99)
(4.31-5.25)
(4.50-5.54)
(4.63-5.75)
60 -min 1.39 1.68 2.07 2.34 2.68 2.92 3.15 3.37 3.64 3.84
(1.27-1.52) (1.54-1.84) (1.89-2.26) (2.14-2.56) (2.43-2.92) (2.64-3.19) (2.84-3.44) (3.02-3.68) (3.23-3.98) (3.38-4.20)
2 -hr 0.830 1.01 1.25 1.42
(0.758-0.912) (0.920-1.10) 1 (1.14-1.37) 1 (1.29-1.56) 11
3 -hr 0.590 0.715 0.887 1.02
(0.540-0.646) (0.656-0.784) (0.811-0.972) (0.929-1.11)
1.65
0.356 0.431 0.535 0.616 0.723 0.808 0.894 0.981 1.10 1.19
6 -hr
(0.328-0.390) (0.397-0.471) (0.491-0.584) 1(0.563-0.672)11(0.657-0.787) (0.728-0.879) 1(0.799-0.971)11(0.868-1.07) (0.958-1.19) ( 1.03-1.30)
0.209 0.253 0.316 0.366 0.434 0.489 0.546 0.606 0.688 0.755
12 -hr
(0.193-0.229) (0.233-0.277) (0.290-0.345) (0.335-0.399) (0.394-0.472) (0.440-0.530) (0.487-0.591) (0.533-0.654) (0.595-0.744) I (0.642-0.817)
0.123 0.148 0.185 0.213 0.252 0.283 0.314 0.346 0.389 0.424
24 -hr
(0.115-0.131) (0.139-0.158) ( 0.173-0.197) ( 0.200-0.228) ( 0.235-0.269) (0.262-0.302) (0.290-0.336) (0.319-0.371) (0.357-0.419) (0.387-0.457)
0.072 0.086 0.107 0.123 0.144 0.160 0.177 0.194 0.217 0.235
2 -day
(0.067-0.077) 1(0.081-0.092)1(0.100-0.114) (0.115-0.131) (0.134-0.154) F(0-
1.82
1.98
2.14
2.35
2.51
(1.49-1.80)
(1.64-1.99)
(1.77-2.17)
(1.90-2.34)
(2.07-2.57)
(2.19-2.75)
1.32
1.74
1.19
1.45
1.57
1.88
(1.08-1.30)
(1.19-1.44)
(1.29-1.58)
(1.40-1.72)
(1.53-1.90)
(1.63-2.05)
149-0.172) (0.164-0.190) (0.179-0.209) (0.199-0.235) (0.215-0.255)
3 -day 0.051 0.061 0.075 0.086
(0.047-0.054) (0.057-0.065) (0.070-0.080) (0.080-0.092)
4 -day 0.040 0.048 0.059 0.068
(0.038-0.043) (0.045-0.051) (0.055-0.063) (0.063-0.072)
0.101 0.112 0.124 0.136 0.153 0.166
(0.094-0.108) (0.104-0.120) (0.115-0.133) (0.125-0.147) (0.140-0.165) (0.151-0.179)
0.079 0.088 0.098 0.107 0.120 0.131
(0.074-0.085) (0.082-0.095) 1(0.090-0.105)1(0.099-0.115)
0.026 0.031 0.038 0.043 0.050 0.056 0.062 0.068 0.076 0.082
7 -day
(0.025-0.028) (0.030-0.033) (0.036-0.040) (0.041-0.046) (0.047-0.054) (0.052-0.060) (0.058-0.066) (0.063-0.073) (0.070-0.082) ( 0.075-0.089)
0.021 0.025 0.030 0.034 0.039 0.043 0.047 0.051 0.057 0.062
10 -day
(0.020-0.022) (0.023-0.026) (0.028-0.032) (0.032-0.036) (0.036-0.041) (0.040-0.046) (0.044-0.050) (0.048-0.055) (0.053-0.061) (0.057-0.066)
20 -day 0.014 0.016 0.019 0.022 0.025 0.028 -0.0-3o--T-o--033F
F
0.020
0.021
0.023
0.025
0.027
0.029
(0.017-0.018)
(0.019-0.021)
(0.020-0.023)
(0.022-0.025)
(0.023-0.026)
(0.025-0.029)
(0.027-0.031)
0.014
0.016
0.017
0.019
0.020
0.022
0.023
(0.110-0.130)
(0.119-0.142)F
0.036 0.039
(0.013-0.015) (0.016-0.017) (0.018-0.021) (0.021-0.023) (0.024-0.027) (0.026-0.029) (0.028-0.032) (0.030-0.035) (0.034-0.039) (0.036-0.042)
30 -day 0.012 0.014 0.016
(0.011-0.012) 1(0.013-0.014)1(0.015-0.017)
45day 0.010 0.011 0.013
(0.009-0.010) (0.011-0.012) (0.012-0.014)
0.010 60 -day
F(0. 008-0.009)11(0.010-0.011)11(0.011-00.012)1
0.017
11
0.020
0.021
0.023
0.025
0.027
0.029
(0.017-0.018)
(0.019-0.021)
(0.020-0.023)
(0.022-0.025)
(0.023-0.026)
(0.025-0.029)
(0.027-0.031)
0.014
0.016
0.017
0.019
0.020
0.022
0.023
(0.014-0.015)
(0.015-0.017)
(0.016-0.018)
(0.018-0.020)
(0.019-0.021)
(0.020-0.023)
(0.021-0.024)
0.013 0.014 0.015 0.016 0.017 0.018 0.019
X12-0.013) (0.013-0.015) (0.014-0.016) (0.015-0.017) (0.016-0.018) (0.017-0.019) (0.018-0.020)
1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of part
ial duration series (PDS).
ers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for a
duration and average recurrence interv
al) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not
ed against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values.
refer to NOAA Atlas 14 document for more information.
Back to Top
PF graphical
Page 40 of 93
https://hdsc.nws. noaa.gov/hdsc/pfds/pfds_printpage. html?Iat=35.9240&Ion=-79.1995&data=intensity&units=english&series=pds

4/24/2018
Precipitation Frequency Data Server
PDS -based intensity -duration -frequency (IIF) curves
Latitude: 35.92401, Longitude: -79.1995'
10.000
3IIOISX
C
O
a
0.010
a
0 001
Tt7ntIWOi
L
1.co0
Ln
a�
0.100
a
0.010
a
00011 1 1 I 1 1 I 1 1 i
1 2 5 10 25 50 100 200 500 1000
Average recurrence interval (years)
NOAA Atlas 14, Volume 2, Version 3 treated (GMT): Tue Apr 24 21:56:10 2018
Back to Top
Maps & aerials
Small scale terrain
Average recurrence
interval
iyears)
— 1
2
5
25
60
100
200
500
1000
Duration
— 5-mrn
— 2-oay
— 10 -min
— 3-0ay
1"in
— "ay
— 3"In
— 7 -day
— 60-mrn
— 10 -day
-- 2 -hr
— 20-aay
— 3-1r
— 30 -day
— 6-u
— 45 -day
— 12 -hr
— 60 -day
L i
L L
L
rp
rq ry
� �
ry
rp
� rq
O
O
N A46
LA
O
N
A V
� O
O
O
IPI O
�
Iv
rrs
IT �c
Duration
Tt7ntIWOi
L
1.co0
Ln
a�
0.100
a
0.010
a
00011 1 1 I 1 1 I 1 1 i
1 2 5 10 25 50 100 200 500 1000
Average recurrence interval (years)
NOAA Atlas 14, Volume 2, Version 3 treated (GMT): Tue Apr 24 21:56:10 2018
Back to Top
Maps & aerials
Small scale terrain
Average recurrence
interval
iyears)
— 1
2
5
25
60
100
200
500
1000
Duration
— 5-mrn
— 2-oay
— 10 -min
— 3-0ay
1"in
— "ay
— 3"In
— 7 -day
— 60-mrn
— 10 -day
-- 2 -hr
— 20-aay
— 3-1r
— 30 -day
— 6-u
— 45 -day
— 12 -hr
— 60 -day
— 24 --hr
Page 41 of 93
https:Hhdsc.nws. noaa.gov/hdsc/pfds/pfds_printpage. html?lat=35.9240&Ion=-79.1995&data=intensity&units=english&series=pds

4/24/2018
Precipitation Frequency Data Server
r3km
2mi
Large scale terrain qq
$lackshury Roanoke
_ k
i
ik
O
Winston-Salem
r • [�ilrliam
Greensboro
Rocky Mount
I Raleigh
NORTH CAROLINA
r
reel
Charlotte
—
_: Fayetterille
100km
ip
Jackso
r
60m,L
yiF
:
Large scale map
Greensb
Derham
rr� r
r RaReigh
North
Carolina
100km hee1
60mi
ti
Large scale aerial
Pke
Rocky Mount
4
Green,.
0
Jacksa
Page 42 of 93
https:Hhdsc.nws. noaa.gov/hdsc/pfds/pfds_printpage. html?lat=35.9240&Ion=-79.1995&data=intensity&units=english&series=pds

4/24/2018
Precipitation Frequency Data Server
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
Page 43 of 93
https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_printpage.html?lat=35.9240&Ion=-79.1995&data=intensity&units=english&series=pds

POINT OF INTEREST #1
Page 44 of 93

Worksheet 3: Time of Concentration (T,) or Travel Time (Tj
Project American Legion
By AAA
Date
4/13/2018
Location
Checked PB
Date
4/13/2018
Check One: FX Pre-Developed Developed
Pre-Developed Conditions
Check One: FV]Tc ❑Tt through subarea
Notes: Space for as many as two segments per flow type can be used for each worksheet.
Include a map, schematic, or description of flow segments
Sheet Flow (Applicable to Tc only)
Segment ID
1. Surface description (table 3-1)...................................
Light Underbrush
2. Manning's roughness coefficient, n (table 3-1)..............
0.4
3. Flow Length, L (total L<= 100 ft)...............................ft
100
4. Two-Year 24-hour rainfall, p2............................................ in
3.55
5. Land Slope, s......................................................ft/ft
0.0600
6. Tt = 0.007 (n L) Compute Tt............. hr
0.22 +
_
P2 0.5 s 0.4
0.22
Shallow Concentrated Flow
Segment ID
7. Surface description (paved or unpaved).......................
unpaved
8. Flow length, L......................................................ft
378
9. Watercourse slope, s..........................................ft/ft
0.0260
10. Average velocity, V (figure 3-1)..............................ft/s
2.60
11 Tt = L Compute Tt............. hr
0.04 +
-
3600V
0.04
Segment ID
12. Cross sectional flow area, a..................................ft2
3
13. Wetted perimeter, Pw...........................................ft
3
14. Hydraulic Radius, r= a/Pw Compute r......................ft
1.00
15. Channel Slope, s................................................ft/ft
0.0580
16. Manning's Roughness coefficient, n.........................
0.011
17. V = 1.49 r 2/3 s 112 Compute V...............ft/s
32.62
n
18. Flow Length, L...................................................ft
850
19 Tt = L Compute Tt............. hr
0.01 +
-
3600V
0.01
Total Tc
0.27
Use Tc (min.)
15.99
Page 45 of 93
(210 -VI -TR -55, Second Ed., June 1986)

Worksheet 3: Time of Concentration (T,) or Travel Time (T)
Project St. Thomas More
By AAA
Date 4/13/2018
Location
Checked PB
Date 4/13/2018
Check One: Pre-Developed FX Developed
Developed Conditions
Check One: FX T, ❑Tt through subarea
Notes: Space for as many as two segments per flow type can be used for each worksheet.
Include a map, schematic, or description of flow segments
Sheet Flow (Applicable to T, only)
Segment ID
1. Surface description (table 3-1)...................................
Light Underbrush
2. Manning's roughness coefficient, n (table 3-1)..............
0.4
3. Flow Length, L (total L<= 100 ft)...............................ft
100
4. Two-Year 24-hour rainfall, P2.............................................. in
3.55
5. Land Slope, s......................................................ft/ft
0.0200
6. Tt = 0.007 (n L) " Compute Tt............. hr
0.34 +
_
P2 0.5 s 0.4
0.34
Shallow Concentrated Flow
Segment ID
7. Surface description (paved or unpaved).......................
unpaved
8. Flow length, L......................................................ft
467
9. Watercourse slope, s..........................................ft/ft
0.0100
10. Average velocity, V (figure 3-1)..............................ft/s
1.61
11 Tt = L Compute Tt............. hr
0.08 +
-
3600V
0.08
Segment ID
12. Cross sectional flow area, a..................................ft2
1.16
13. Wetted perimeter, Pw...........................................ft
4.85
14. Hydraulic Radius, r= a/Pw Compute r......................ft
0.24
15. Channel Slope, s................................................ft/ft
0.0170
16. Manning's Roughness coefficient, n.........................
0.011
17. V = 1.49 r 2/1S '/2Compute V...............ft/s
6.81
n
18. Flow Length, L...................................................ft
575
19 Tt = L Compute Tt............. hr
0.02 +
_
3600V
0.02
Total Tc 0.44
Use Tc (min.) 26.62
Page 46 of 93
(210 -VI -TR -55, Second Ed., June 1986)

STORMWATER MANAGEMENT SUMMARY
Page 47 of 93

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v11
Hyd. No. 1
Pre -Development P0I#1
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 9.110 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 2.96 in
Storm duration
= 24 hrs
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
. Composite (Area/CN) _ [(0.105 x 85) + (0.070 x 98) + (0.689 x 69) + (3.106 x 55)] / 9.110
Q (cfs)
3.00
2.00
1.00
0.00
0 120 240
Hyd No. 1
Pre -Development P0I#1
Hyd. No. 1 -- 1 Year
360 480 600 720 840
Friday, 06 / 15 / 2018
= 2.442 cfs
= 726 min
= 11,287 cuft
= 61*
= 0 ft
= 16.00 min
= Type II
= 484
Q (cfs)
3.00
2.00
1.00
' ` ' 0.00
960 1080 1200 1320 1440 1560
Time (min)
Page 48 of 93

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v11
Hyd. No. 3
Post Development Basin Inflow
Hydrograph type
= SCS Runoff
Storm frequency
= 1 yrs
Time interval
= 2 min
Drainage area
= 14.910 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 2.96 in
Storm duration
= 24 hrs
. Composite (Area/CN) = [(0.123 x 61) + (0.387 x 98)] / 14.910
Q (cfs)
6.00
5.00
3.00
2.00
1.00
0.00
0 120 240
Hyd No. 3
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Development Basin Inflow
Hyd. No. 3 -- 1 Year
Friday, 06 / 15 / 2018
= 5.274 cfs
= 734 min
= 28,458 cuft
= 66*
= 0 ft
= 27.00 min
= Type II
= 484
Q (cfs)
6.00
5.00
4.00
3.00
2.00
1.00
I i I I I I I I� 1 0.00
360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Page 49 of 93

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v11
Hyd. No. 4
Basin Routed
Hydrograph type
= Reservoir
Peak discharge
Storm frequency
= 1 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 3 - Post Development Basin InfAaK. Elevation
Reservoir name
= Pond
Max. Storage
Storage Indication method used
Q (cfs)
6.00
5.00
FA
3.00
2.00
1.00
0.00 ' ' 'e-
0 600
Hyd No. 4
Basin Routed
Hyd. No. 4 -- 1 Year
Friday, 06 / 15 / 2018
= 0.122 cfs
= 1460 min
= 21,640 cuft
= 519.89 ft
= 23,953 cuft
Q (cfs)
6.00
5.00
4.00
3.00
2.00
1.00
0.00
1200 1800 2400 3000 3600 4200 4800 5400 6000
Hyd No. 3 1_1_1_1_1_1_1 Total storage used = 23,953 cuft Time (min)
Page 50 of 93

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v11
Hyd. No. 1
Pre -Development P0I#1
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 9.110 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.57 in
Storm duration
= 24 hrs
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
. Composite (Area/CN) _ [(0.105 x 85) + (0.070 x 98) + (0.689 x 69) + (3.106 x 55)] / 9.110
Q (cfs)
6.00
5.00
3.00
2.00
1.00
0.00
0 120 240
Hyd No. 1
Pre -Development P0I#1
Hyd. No. 1 -- 2 Year
Friday, 06 / 15 / 2018
= 5.402 cfs
= 724 min
= 19,490 cuft
= 61*
= 0 ft
= 16.00 min
= Type II
= 484
Q (cfs)
6.00
5.00
4.00
3.00
2.00
1.00
I i i . I I I I I I. 1 0.00
360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Page 51 of 93

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v11
Hyd. No. 3
Post Development Basin Inflow
Hydrograph type
= SCS Runoff
Storm frequency
= 2 yrs
Time interval
= 2 min
Drainage area
= 14.910 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 3.57 in
Storm duration
= 24 hrs
. Composite (Area/CN) = [(0.123 x 61) + (0.387 x 98)] / 14.910
Q (cfs)
10.00
. 11
4.00
2.00
0.00
0 120 240
Hyd No. 3
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Development Basin Inflow
Hyd. No. 3 -- 2 Year
360 480 600
Friday, 06 / 15 / 2018
= 9.614 cfs
= 732 min
= 45,389 cuft
= 66*
= 0 ft
= 27.00 min
= Type II
= 484
Q (cfs)
10.00
. 11
4.00
2.00
/ I I I I I I I%- 1 0.00
720 840 960 1080 1200 1320 1440 1560
Time (min)
Page 52 of 93

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v11
Hyd. No. 4
Basin Routed
Hydrograph type
= Reservoir
Peak discharge
Storm frequency
= 2 yrs
Time to peak
Time interval
= 2 min
Hyd. volume
Inflow hyd. No.
= 3 - Post Development Basin InfAaK. Elevation
Reservoir name
= Pond
Max. Storage
Storage Indication method used.
Basin Routed
Friday, 06 / 15 / 2018
= 0.168 cfs
= 1460 min
= 34,861 cuft
= 520.13 ft
= 38,834 cuft
Q (cfs) Hyd. No. 4 -- 2 Year Q (cfs)
10.00 10.00
8.00 8.00
6.00 6.00
4.00 4.00
2.00 2.00
0.00 0.00
0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000
Hyd No. 4 Hyd No. 3 1_1_1_1_1_1_1 Total storage used = 38,834 cuft Time (min)
Page 53 of 93

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v11
Hyd. No. 1
Pre -Development P0I#1
Hydrograph type
= SCS Runoff
Storm frequency
= 25 yrs
Time interval
= 2 min
Drainage area
= 9.110 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 6.11 in
Storm duration
= 24 hrs
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
. Composite (Area/CN) _ [(0.105 x 85) + (0.070 x 98) + (0.689 x 69) + (3.106 x 55)] / 9.110
Q (cfs)
24.00
16.00
12.00
M
4.00
0.00
0 120 240
Hyd No. 1
Pre -Development P0I#1
Hyd. No. 1 -- 25 Year
Friday, 06 / 15 / 2018
= 23.05 cfs
= 724 min
= 67,048 cuft
= 61*
= 0 ft
= 16.00 min
= Type II
= 484
Q (cfs)
24.00
20.00
16.00
12.00
4.00
I i i i i i i 1 r. 0.00
360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Page 54 of 93

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v11
Hyd. No. 3
Post Development Basin Inflow
Hydrograph type
= SCS Runoff
Storm frequency
= 25 yrs
Time interval
= 2 min
Drainage area
= 14.910 ac
Basin Slope
= 0.0%
Tc method
= User
Total precip.
= 6.11 in
Storm duration
= 24 hrs
. Composite (Area/CN) = [(0.123 x 61) + (0.387 x 98)] / 14.910
Q (cfs)
35.00
30.00
25.00
15.00
10.00
5.00
0.00
0 120 240
Hyd No. 3
Peak discharge
Time to peak
Hyd. volume
Curve number
Hydraulic length
Time of conc. (Tc)
Distribution
Shape factor
Post Development Basin Inflow
Hyd. No. 3 -- 25 Year
Friday, 06 / 15 / 2018
= 33.33 cfs
= 732 min
= 136,500 cuft
= 66*
= 0 ft
= 27.00 min
= Type II
= 484
Q (cfs)
35.00
30.00
25.00
20.00
15.00
10.00
NWiZ17
I i i i I I I I I I_ 1 0.00
360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Page 55 of 93

Hydrograph Report
Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v11
Friday, 06 / 15 / 2018
Hyd. No. 4
Basin Routed
Hydrograph type
= Reservoir
Peak discharge
= 0.317 cfs
Storm frequency
= 25 yrs
Time to peak
= 1462 min
Time interval
= 2 min
Hyd. volume
= 80,748 cuft
Inflow hyd. No.
= 3 - Post Development Basin In1Vbc. Elevation
= 521.43 ft
Reservoir name
= Pond
Max. Storage
= 123,420 cuft
Storage Indication method used.
Basin Routed
see I off go :go so else Ms
Page 56 of 93

534.5
534
533.5
533
532.5
532
531.5
531
530.5
530
529.5
529
528.5
528
275
527
Z 526.5
w 526
255
525
524.5
524
235
523
5225
522
21 5
521
5205
520
195
519
IN
Min Pipe Cover (ft[:
Max HGL (ft[:
Link ID:
Length Ift[:
Dia 6n):
slope [a7a1
Up lnvert[ft)
Dn Invert [ft)
Max 4 [ds
Max Vel (IVs):
Max Depth (ft):
1+00 1+20 1+40 1+60 1+80 2+00 2+20 2+40 2+60 2+80 3+00 3+20 3+40 3+60 3+60 4+00 4+20 4+40 4+60 4+80 5+00 5+20 5+40 5+60 5+30 6+00 6+20 6+40 6+60 6+80
Station WI
D 21 [Storm)
AD 20[Storm)
CD 1 (Storm)
FES 1 (Storm)
529.90
530.50
531.29
525.77
526.90
524.80
521.32
519.77
400
527.75
1
525.84
522.87
521.31
{Storm} p.Zl
(Storm)
{Storm} P-20
[Sturm)
{Sturm} P.1 (Sturm)
121.20
264.05
194.31
18.00
18.00
24.00
8.0157
8.0125
0.8088
526.90
524.80
521.32
525.00
521.50
519.77
7.98
8.52
1903.
7.87
7.27
7.36
0.84
0.95
1.51
Autodesk Storm and Sanitary Analysis
Page 57 of 93

534.5
534
533.5
533
532.5
532
531.5
531
530.5
530
529.5
529
528.5
528
5275
527
Z 526.5
w 526
5255
525
524.5
524
5235
523
5225
522
5215
521
5205
520
5195
519
IN
Min Pipe Cover (ft):
Max HGL (ft):
Link ID:
Length (ftl:
Dia 6n):
Slope "f
Up In-t(ft)
Dn Invert (ft)
Max 4
Max Vel (IVs):
Max Depth [ft):
Profile Plot
Main Street Storm Sewer
__'_______•______'_______•------ _--- _--•--- _---- ','•'•'
-
- ' --
__ -- ---
--- --
:
LB 1 (St=1
FES 1 (Storm)
528.25
o
528.71
M H
P
531.29
o�
525.77
525.00
m� u
W___•______'_____ - _--- --- ______=raw a___`______�_______`______�______'_______•______'_______�______'_______
•""--- ----------- --------------- ---
--- ----------- --- ------ ------- ---------------
� `______�_______`______�_____
--- --
______________
-- ---
______ _______ ______ _______
--- "--- ------ - "--- --""-- -----
______ _______ ______ __
-- ------ ---""--
N N
: : : 'G
w
d p : : -
------'�
:
:-----------------------------•'--
0
-P^e'-G---•------•-------•-------------- •------
r
;------- :----
400
525.95
- -----
--- --
524.96
522.87
521.31
- Slope 8 0880 flirt
Length 315 23 k
(Sturm)
---; - --o- N --
- Dp Invert 525.00 fl
Dia 18.00 in
1 [Storm)
-- ---
- --`-"w
Ye -o--
Dn Invert 524 04 fl
Slope 80880 flik
194.31
15.00
up Invert sz3,9a fl
24.00
o -M
-p
-
Do Invek 521 42 fl
8.8880
Link ID (Storm} P-1 (Slot
525.80
523.94
521.32
Length 194 31 fl
--
-
521.42
519.77
Die 2408
5.31
--- ----- - _
6.64
19.03
Slope 8.0888 k)fl
- --
---
5.85
7.36
IJp Inver1521 32 ft
--
0.90
Dn Inven 519.77 ft
1+08 1+20 1+40 1+60 1+88 2+80 2+20 2+40 2+68 2+80 3+00
3+20 3+48 3+60 3+30 4+00 4+20
4+48 4+60 4+80 5+00 5+28 5+40 5+60
5+80 6+08 6+20 6+40 6+60
6+88 7+00 7+20 7+40
Station W1
D 11 [Storm)
LB 10 [Storm)
LB 1 (St=1
FES 1 (Storm)
528.25
528.71
531.29
525.77
525.00
524.00
521.32
519.77
400
525.95
524.96
522.87
521.31
{Storm} P.11
(Sturm)
{Sturm} P.10
(Sturm)
{Storm} P
1 [Storm)
120.51
315.23
194.31
15.00
18.00
24.00
8.0880
8.8880
8.8880
525.80
523.94
521.32
524.84
521.42
519.77
5.31
6.64
19.03
5.38
5.85
7.36
0.94
0.90
1.51
Autodesk Storm and Sanitary Analysis
Page 58 of 93

Hydrograph Return Period Reda plow Hydrographs Extension for AutoCAD® Civil 3D® 2016 by Autodesk, Inc. v11
Hyd.
Hydrograph
Inflow
Peak Outflow (cfs)
Hydrograph
No.
type
hyd(s)
Description
(origin)
1 -yr
2 -yr
3 -yr
5 -yr
10 -yr
25 -yr
50 -yr
100 -yr
1
SCS Runoff
------
2.442
5.402
-------
-------
-------
23.05
-------
-------
Pre -Development POI#1
3
SCS Runoff
------
5.274
9.614
-------
-------
-------
33.33
-------
-------
Post Development Basin Inflow
4
Reservoir
3
0.122
0.168
-------
-------
-------
0.317
-------
-------
Basin Routed
Proj. file: Temp.gpw
Friday, 06 / 15 / 2018 Page 59 of 93

STORMWATER CONVEYANCE SUMMARY
Page 60 of 93

Culvert Calculator Report
25-50 RATIONAL
Solve For: Headwater Elevation
Culvert Summary
Allowable HW Elevation
499.28 ft
Headwater Depth/Height 0.87
Computed Headwater Elew
496.65 ft
Discharge 209.62 cfs
Inlet Control HW Elev.
496.43 ft
Tailwater Elevation 0.00 ft
Outlet Control HW Elev.
496.65 ft
Control Type Entrance Control
Title: American Legion Project Engineer: aarabi
I:\...\culvert sizing\model\projectl.cvm Pennoni AssociatesPhiladelphia Cu19"l1&16Jteif 0.3 [03.03.00.04]
08/03/18 01:35:43 PMO Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 1 of 1
Grades
Upstream Invert
Length
492.28 ft
65.00 ft
Downstream Invert
Constructed Slope
491.57 ft
0.010923 ft/ft
Hydraulic Profile
Profile
Slope Type
Flow Regime
Velocity Downstream
S2
Steep
Supercritical
11.49 ft/s
Depth, Downstream
Normal Depth
Critical Depth
Critical Slope
2.36 ft
2.15 ft
2.92 ft
0.003912 ft/ft
Section
Section Shape
Section Material
Section Size
Number Sections
Circular
Concrete
60 inch
2
Mannings Coefficient
Span
Rise
0.013
5.00 ft
5.00 ft
Outlet Control Properties
Outlet Control HW Elev.
Ke
496.65 ft
0.20
Upstream Velocity Head
Entrance Loss
1.21 ft
0.24 ft
Inlet Control Properties
Inlet Control HW Elev. 496.43 ft
Inlet Type Groove end w/headwall
K 0.00180
M 2.00000
C 0.02920
Y 0.74000
Flow Control
Area Full
HDS 5 Chart
HDS 5 Scale
Equation Form
Unsubmerged
39.3 ft2
1
2
1
Title: American Legion Project Engineer: aarabi
I:\...\culvert sizing\model\projectl.cvm Pennoni AssociatesPhiladelphia Cu19"l1&16Jteif 0.3 [03.03.00.04]
08/03/18 01:35:43 PMO Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 1 of 1

Culvert Designer/Analyzer Report
25-50 <Rational>
Analysis Component
Storm Event
Design
Discharge
209.02 cfs
Peak Discharge Method: Rational
Design Return Period
25 year
Check Return Period
50 year
Design Peak Discharge
209.02 cfs
Check Peak Discharge
228.52 cfs
Total Area
321.26 acres
Time of Concentration
63.99 min
Rational Coefficient
0.26
Intensity
2.74 in/hr
Area
Subwatershed (acres) C
1 321.26 0.26
Tailwater Conditions: Constant Tailwater
Tailwater Elevation N/A ft
Name Description Discharge HW Elev. Velocity
Weir Not Considered N/A N/A N/A
Title: American Legion Project Engineer: aarabi
I:\...\culvert sizing\model\projectl.cvm Pennoni AssociatesPhiladelphia Culy"P&lb 9eif 0.3 [03.03.00.04]
06/13/18 11:58:14 PMO Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 1 of 1

Culvert Calculator Report
25-50 Entrance Culvert
Solve For: Headwater Elevation
Culvert Summary
Allowable HW Elevation
0.00 ft
Headwater Depth/Height 0.80
Computed Headwater Elew
520.00 ft
Discharge 2.83 cfs
Inlet Control HW Elev.
519.95 ft
Tailwater Elevation 0.00 ft
Outlet Control HW Elev.
520.00 ft
Control Type Entrance Control
Title: American Legion Project Engineer: aarabi
I:\...\model\entrance culvert\entrance culvert.cvm Pennoni AssociatesPhiladelphia Culy"l1&l6teif 0.3 [03.03.00.04]
08/03/18 02:12:14 PMO Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 1 of 1
Grades
Upstream Invert
Length
519.00 ft
71.26 ft
Downstream Invert
Constructed Slope
518.00 ft
0.014033 ft/ft
Hydraulic Profile
Profile
Slope Type
Flow Regime
Velocity Downstream
S2
Steep
Supercritical
5.77 ft/s
Depth, Downstream
Normal Depth
Critical Depth
Critical Slope
0.53 ft
0.53 ft
0.68 ft
0.005921 ft/ft
Section
Section Shape
Section Material
Section Size
Number Sections
Circular
Concrete
15 inch
1
Mannings Coefficient
Span
Rise
0.013
1.25 ft
1.25 ft
Outlet Control Properties
Outlet Control HW Elev.
Ke
520.00 ft
0.20
Upstream Velocity Head
Entrance Loss
0.27 ft
0.05 ft
Inlet Control Properties
Inlet Control HW Elev. 519.95 ft
Inlet Type Groove end w/headwall
K 0.00180
M 2.00000
C 0.02920
Y 0.74000
Flow Control
Area Full
HDS 5 Chart
HDS 5 Scale
Equation Form
Unsubmerged
1.2 ft2
1
2
1
Title: American Legion Project Engineer: aarabi
I:\...\model\entrance culvert\entrance culvert.cvm Pennoni AssociatesPhiladelphia Culy"l1&l6teif 0.3 [03.03.00.04]
08/03/18 02:12:14 PMO Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 1 of 1

Culvert Designer/Analyzer Report
Entrance Culvert
Analysis Component
Storm Event
Design
Discharge
2.83 cfs
Peak Discharge Method: Rational
Design Return Period
25 year
Check Return Period
50 year
Design Peak Discharge
2.83 cfs
Check Peak Discharge
3.01 cfs
Total Area
2.09 acres
Time of Concentration
25.19 min
Rational Coefficient
0.30
Intensity
4.76 in/hr
Area
Subwatershed (acres) C
1 2.09 0.30
Tailwater Conditions: Constant Tailwater
Tailwater Elevation N/A ft
Name Description Discharge HW Elev. Velocity
Weir Not Considered N/A N/A N/A
Title: American Legion Project Engineer: aarabi
I:\...\model\entrance culvert\entrance culvert.cvm Pennoni AssociatesPhiladelphia Cul9"P&16teif 0.3 [03.03.00.04]
06/13/18 11:13:02 PMO Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 1 of 1

STORMWATER BMP DESIGN SUMMARY
Page 65 of 93

(P71e=nnoniw
Wet Detention
Basin Design
Project Information
Project: American Legion
Location: Hwy
54
Project Number: AMLG1701
Date: Oct -17-2018
Designed: AAA
Checked: PCB
Site Information
Sub Area Location:
Wet Detention Basin 1
Drainage Area (DA) =
644,552
sf
Impervious Area (IA) =
98,981
sf
Percent Impervious (1) =
15.4
%
Elevations
Top of Bank Elevation =
523.00
ft
Emergency Elevation =
522.00
ft
Temporary Pool Elevation =
519.67
Permanent Pool Elevation =
519.50
ft
Bottom of Pond Elevation =
513.00
ft
Sediment Cleanout, Bottom Elevation =
512.00
ft
Basin Areas/Volumes
Area of Permanent Pool =
59,340
sf
A pefm_pool (includes main pond & forebays) (Elev = 519.50 )
Area of Bottom of Shelf =
54,332
sf
A bot shelf (includes main pond & forebays)
Area of Bottom of Pond =
33,709
sf
A bot_pond (excluding sediment storage & forebays)
Area of Temporary Pool =
63,180
sf
Atemp_pond (includes main pond and forebays) (Elev = 519.67 )
Volume, main pool =
232,762
cf
V ma;o_pool (from Hydraflow)
Volume, forebay (sum of forebays) =
43,722
cf
Vforebay (from Hydraflow)
Volume, permanent pool =
276,484
cf
V perm_pool (Vforebay+Vmain_pool)
Forebay % of permanent pool volume =
15.8
%
Average Depth
Depth of Pond =
6
ft
Depth (dist. btwn. bot. of shelf & btm. of pond, excludes sediment)
Average Depth =
5.34
ft
Use Average Depth of =
5.00
ft
Round down to nearest 0.5
Required Surface Area - Wetland
SA/DA =
0.58
(85%
TSS Removal via Pond)
Min Req'd Surface Area =
3,738
sf (at
Permanent Pool)
Required Storage Volume - Using Simple
Method
Design Storm =
1.0
inch
(Project Does Not Drain to SA Waters)
Determine Rv Value =
0.05 + 0.009
(I) =
0.19 in/in
Storage Volume Required =
10,109
cf (above Permanent Pool)
Side Slopes of Pond =
3 : 1
Is Permenant Pool Surface Area Sufficient (yes/no)?
Yes ( 59340 > 3738) sf
Page 66 of 93

Pei
1.0 inch Volume Elevation
Required Temporary Pool Volume =
Temporary Pool Lower Elevation Bound =
Temporary Pool Upper Elevation Bound =
Temporary Pool Lower Volume Bound =
Temporary Pool Upper Volume Bound =
Temporary Pool Elevation =
Orifice Sizing - Wet Detention
Wet Detention Basin Design
10,109 cu ft
519.50
520.00
0 cu ft
30,468 Cu ft
519.67
Q2 Days =
0.5476
cfs
Q5 Days =
0.2190
cfs
Orifice Size =
3.00
in
Driving Head (Ho) =
0.01
ft
Q orifice =
0.028
cfs
Drawdown Time =
4.2
days
less than 5 days (yes/no) ?
Yes
65,777
greater than 2 days (yes/no) ?
Yes
1.5
Anti -Flotation Device
69,080
67,428
Outside Length =
4.00
ft
Outside Width =
4.00
ft
Inside Length =
3.00
ft
Inside Width =
3.00
ft
Bottom Thickness =
0.50
ft
Top of Riser =
521.50
ft
Invert of Riser =
512.00
ft
Area =
16.0
sf
Volume =
160
cf
Weight=
9,984
lbs
Factor of Safety =
1.10
WT Req'd of Anti -Flotation Device =
10,982
lbs
Volume of Concrete Req'd =
125.4
cf
Depth Provided =
3.50
ft
Volume Provided =
130.5
cf
WT of Anti -Flotation Device Provided =
11,432
lbs
Contour
Contour
Area
Incremental Accumulated
Volume Volume, S
Stage, Z
sq ft
cu ft
cu ft
ft
519.50
59,340
0
0
0.0
520.00
62,530
30,468
30,468
0.5
521.00
65,777
64,153
94,621
1.5
522.00
69,080
67,428
162,049
2.5
523.00
72,439
70,759
232,808
3.5
(Flowrate required for a 2 day drawdown)
(Flowrate required for a 5 day drawdown)
(Diameter)
(Outside Dim. = 4 -ft x 4 -ft, Inside Dim. = 3 -ft x 3 -ft)
(Water Displaced - Top of Riser to Bottom of Riser)
(Weight Water Displaced)
(Unit WT of Concrete = 150 pcf) Submerged Concrete Unit Weight 87.6 pcf
(4 -ft x 4 -ft Box filled 1.25 -ft deep with concrete)
OK
Page 67 of 93

RIP -RAP CALCULATIONS
Page 68 of 93

7 (Pennon'
Riprap Outlet Protection Design
Project: American Legion
Location:
Chapel Hill, NC
Project Number:
AMLG1701
Date:
Aug -03-2018
Designed:
AAA
Checked:
PB
Outlet ID:
FES #1
15 in.
Pipe diameter=
15 inches
Pipe slope=
0.8 %
Roughness Coef.=
0.013
Full Flow Capacity=
6.36 cfs Inlcudes 1.1 Factor of Safety
Full flow velocity=
5.18 ft/sec
2
Fi¢ure 8.06.b.1
0 1 2 3 4 5 6 7 8 9 10
Pipe diameter (ft)
Zone from graph above =
1
Diameter
Thickness
Is grade of apron 10% or more:
Y
Y/N
4
Zone used =
2
Length =
7.5 ft.
Outlet pipe diameter=
15 in.
Width at Outlet =
3.8 ft.
Outlet flowrate=
6.4 cfs
Width at end of Pad=
12.4 ft.
Outlet velocity=
5.18 ft/sec
Stone diameter =
8 in.
Material =
Class B
Thickness =
18 in.
Zone
Material
Diameter
Thickness
Length
1
Class A
4
9
4 x D(o)
2
Class B
8
18
6 x D(o)
3
Class 1
10
25.5
8 x D(o)
4
Class 1
10
25.5
8 x D(o)
5
Class 11
14
34.5
10 x D(o)
6
Class 11
1 14
34.5
10 x D(o)
7
1
Special study
required
5
4
Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual
Page 69 of 93

7 (Pennon'
Riprap Outlet Protection Design
Project: American Legion
Location:
Chapel Hill, NC
Project Number:
AMLG1701
Date:
Aug -03-2018
Designed:
AAA
Checked:
PB
Outlet ID:
FES #2
15 in.
Pipe diameter=
15 inches
Pipe slope=
1.4 %
Roughness Coef.=
0.013
Full Flow Capacity=
8.41 cfs Inlcudes 1.1 Factor of Safety
Full flow velocity=
6.85 ft/sec
2
Fi¢ure 8.06.b.1
0 1 2 3 4 5 6 7 8 9 10
Pipe diameter (ft)
Zone from graph above =
1
Diameter
Thickness
Is grade of apron 10% or more:
Y
Y/N
4
Zone used =
2
Length =
7.5 ft.
Outlet pipe diameter=
15 in.
Width at Outlet =
3.8 ft.
Outlet flowrate=
8.4 cfs
Width at end of Pad=
12.4 ft.
Outlet velocity=
6.85 ft/sec
Stone diameter =
8 in.
Material =
Class B
Thickness =
18 in.
Zone
Material
Diameter
Thickness
Length
1
Class A
4
9
4 x D(o)
2
Class B
8
18
6 x D(o)
3
Class 1
10
25.5
8 x D(o)
4
Class 1
10
25.5
8 x D(o)
5
Class 11
14
34.5
10 x D(o)
6
Class 11
1 14
34.5
10 x D(o)
7
1
Special study
required
5
4
Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual
Page 70 of 93

7 (Pennon'
Riprap Outlet Protection Design
Project: American Legion
Location:
Chapel Hill, NC
Project Number:
AMLG1701
Date:
Aug -03-2018
Designed:
AAA
Checked:
PB
Outlet ID:
FES #3
60 in.
Pipe diameter=
60 inches
Pipe slope=
1 %
Roughness Coef.=
0.013
Full Flow Capacity=
181.50 cfs Inlcudes 1.1 Factor of Safety
Full flow velocity=
9.24 ft/sec
2
Fi¢ure 8.06.b.1
0 1 2 3 4 5 6 7 8 9 10
Pipe diameter (ft)
Zone from graph above =
1
Diameter
Thickness
Is grade of apron 10% or more:
N
Y/N
4
Zone used =
1
Length =
20.0 ft.
Outlet pipe diameter=
60 in.
Width at Outlet =
15.0 ft.
Outlet flowrate=
181.5 cfs
Width at end of Pad=
38.1 ft.
Outlet velocity=
9.24 ft/sec
Stone diameter =
4 in.
Material =
Class A
Thickness =
9 in.
Zone
Material
Diameter
Thickness
Length
1
Class A
4
9
4 x D(o)
2
Class B
8
18
6 x D(o)
3
Class 1
10
25.5
8 x D(o)
4
Class 1
10
25.5
8 x D(o)
5
Class 11
14
34.5
10 x D(o)
6
Class 11
1 14
34.5
10 x D(o)
7
1
Special study
required
5
4
Calculations based on NY DOT method - Pages 8.06.05 through 8.06.06 in NC Erosion Control Manual
Page 71 of 93

WET DETENTION POND OPERATION AND MAINTENANCE PLAN
Page 72 of 93

NCDEQ Stormwater Desiqn Manual
A-7. SCM Operation & Maintenance
• Access & Maintenance Easements
• Inspection & Maintenance Agreements
• Inspection & Maintenance Record Keeping
• Maintenance Responsibilities
• Providing for Maintenance Expenses
• Emergency Maintenance
• Debris & Litter Removal
• Sediment Removal & Disposal
• Stability & Erosion Control
• Maintenance of Mechanical Components
• Vegetation Maintenance
• Maintenance of the Aquatic Environment
• Insect Control
• Maintenance of Other Project Features
=1
Enr[rvnmenlc!
Quality
SCMs are crucial in protecting water quality from the impacts of development. However, no
matter how well they are designed and constructed, SCMs will not function correctly nor
remain attractive unless they are properly operated and maintained. Maintenance problems
with SCMs are also less costly to correct when they are caught early.
Regular inspection and maintenance is an ongoing regulatory responsibility for most required
SCMs— These responsibilities typically include regular inspections throughout the year,
maintaining inspection records, and often annual inspections and reporting. A qualified
professional should conduct SCM inspections. NC State University offers a SCM Inspection
and Maintenance Certification Program: http://www.bae.ncsu.edu/topic/bmp-im/ There are
also many companies in NC that specialize specifically in SCM inspection and maintenance.
This chapter will discuss the logistical issues associated with SCM operation and
maintenance as well as provide an overview of some of the typical tasks associated with
maintaining most SCMs. Each of the individual SCM chapters in this manual also include a
table explaining specific inspection and maintenance activities required for a particular SCM
to ensure its proper functioning.
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Access and Maintenance Easements
SCMs on private property should have access and maintenance easements to provide
the legal authority for inspections and maintenance activities. The location and
configuration of easements should be established during the design phase and be
clearly shown on the design drawings. The entire footprint of the SCM system should be
included in the access and maintenance easement, plus an additional ten or more feet
around the SCM to provide enough room for the equipment and activities necessary to
complete maintenance tasks. This SCM system includes components such as the side
slopes, forebay, riser structure, SCM device, and basin outlet, dam embankment, outlet,
and emergency spillway.
Access and maintenance easements should be designed and constructed considering
the maintenance tasks that may be needed. If heavy equipment will be necessary to
perform maintenance tasks (such as for devices with a forebay that will require
sediment clean-out), typically a roadway with a minimum width of ten feet to the SCM
needs to be available. Easements are usually held by the person responsible for the
SCM facility, whether an individual, a corporation, or a government. Easements for
SCMs that are not publicly maintained require provisions that allow the permitting entity
access for inspection and maintenance.
Inspection & Maintenance Agreements
SCM facilities are typically built, owned and maintained by non-governmental entities. To insure
proper long-term maintenance, an Inspection and Maintenance Agreement should be part of the
design plans for any SCM. For regulatory purposes, authorities may require that these
agreements be signed and notarized. An Inspection and Maintenance Agreement will typically
include the following:
• The frequency of inspections that are needed (based on the type of SCM proposed).
• The components of the SCM that need to be inspected.
• The types of problems that may be observed with each SCM component.
• The appropriate remedy for any problems that may occur.
Sample Inspection and Maintenance Agreement provisions are included at the end of each
SCM chapter. The most effective Inspection and Maintenance Agreements are site- specific for
the SCM components that are used on the site as well as any conditions that are unique to the
site (for example, the presence of steep slopes that should be inspected for soil stability).
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Table 1: Required Inspection Frequency for SCMs
Monthly and within 24 hours after every water
quality storm (greater than 1.5 inches in
Coastal Counties and greater than 1.0 inch
elsewhere)
Quarterly and within 24 hours after every water
quality storm (greater than 1.5 inches in
Coastal Counties and greater than 1.0 inch
elsewhere)
Stormwater Wetlands
Wet Detention Basins
Bioretention Cells
Level Spreaders
Infiltration Devices
Sand Filters
Extended Dry Detention Basins
Permeable Pavement
Rooftop Runoff Management
Filter Strips *
Grassed Swales
Restored Riparian Buffers
*Although these devices require quarterly inspection, mowing will usually be done at more frequent intervals
during the growing season.
To summarize Table 1, devices that include vegetation in a highly engineered system require
inspection monthly and after large storm events to catch any problems with flow conveyance or
vegetative health before they become serious. All other SCMs should be inspected at least
quarterly and after large storm events.
When required, signed and notarized Inspection and Maintenance Agreements should be
recorded with the appropriate Register of Deeds. The responsible party should keep a copy of
the Inspection and Maintenance Agreement along with a current set of SCM plans at a known
set location. It is also crucial that these documents be passed on when responsibility for
maintenance is transferred to a different party.
Inspection & Maintenance Record Keeping
All inspection and maintenance activities should be recorded. One easy way to do this is to
create an Inspection and Maintenance checklist based on the Inspection and Maintenance
Agreement. The checklist, at a minimum, should include the following:
• Date of inspection.
• Condition of each of the SCM elements.
• Any maintenance work that was performed (as well as who performed the work).
• Any issues noted for future maintenance (sediment accumulating, vegetation needing
pruning or replacement, etc.).
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Each SCM should have its own maintenance record. Records should be kept in a log in a
known set location. Any deficient SCM elements noted in the inspection should be corrected,
repaired or replaced in a timely manner. Some deficiencies can affect the integrity of structures,
safety of the public, and the function of the SCM.
Major repairs or maintenance work should include the same level of inspection and
documentation as original installations. Inspection checklists and record logs should be kept in
a known set location.
Maintenance Responsibilities
As stated in the section above, maintenance is usually the responsibility of the owner, which in
most cases is a private individual, corporation, or home owner's association. Simple
maintenance items such as minor landscaping tasks, litter removal, and mowing can be done by
the owner, or can be incorporated in conventional grounds maintenance contracts for the overall
property.
Although a non-professional can undertake many maintenance tasks effectively, a professional
should be consulted periodically to ensure that all needs of the SCM facility are met. Some
elements that would benefit from professional judgment include structures, outlets,
embankments, and dams by a professional engineer, as well as plant system health by an
appropriate plant professional. Some developing problems may not be obvious to the untrained
eye.
In addition, it is advisable to have professionals do the more difficult or specialized work. Filling
eroded areas and soil -disturbing activities, such as re -sodding or replanting vegetation, are
tasks that are best assigned to a professional landscaping firm. If the work is not done properly
the first time, not only will the effort have been wasted, but also the facility may have been
damaged by excessive erosion. Grading and sediment removal are best left to professional
contractors. Appropriate professionals (e.g. SCM maintenance specialists, professional
engineers, aquatic plant specialists, etc.) should be hired for specialized tasks such as
inspections of vegetation and structures.
Providing for Maintenance Expenses
The expenses associated with maintaining a SCM are highly dependent on the SCM type and
design. However, the most important factor that determines the cost of SCM maintenance is the
condition of the drainage area upstream of the SCM. If a drainage area conveys a high load of
sediment and other pollutants to a SCM, the cost of maintaining the SCM will increase
dramatically. Preventing pollution in the drainage area as much as possible will reduce the cost
of SCM maintenance.
A funding mechanism should be created and maintained at a level that provides adequate
funding to pay for the maintenance expenses over the lifetime of the SCM. One option is to
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establish an escrow account, which can be spent solely for sediment removal, structural,
biological or vegetative replacement, major repair, or reconstruction of the SCMs. In the case of
a residential subdivision, the escrow account could be funded by a combination of an initial
payment by the developer and regular contributions by the homeowners' association. For an
example of how to legally structure such an account, please see the Phase 11 model stormwater
ordinance at the Stormwater Program web site. Routine maintenance costs may be relatively
easy to estimate, and include the expenses associated with the following activities:
• Conducting SCM inspections at the intervals shown in Table 1.
• Maintaining site safety, including any perimeter fences and other access inhibitors (trash
racks or pipe grates).
• Removing trash.
• Removing sediment that has accumulated in any components of the SCM.
• For infiltration -type systems, maintaining the filtering media and cleaning or replacing it
when necessary.
• Restoring soils to assure performance.
• Mowing turf grasses or maintaining other types of ground covers
• Controlling weeds and other invasive plants
• Pruning woody vegetation.
• Thinning desired vegetation
• Replacing dead vegetation.
• Stabilizing any eroding side slopes.
• Repairing damaged or eroded outlet devices and conveyance systems.
• Repairing embankments, dams, and channels due to erosion or rodents.
Emergency maintenance costs are more difficult to estimate. They depend on the frequency of
occurrence and the nature of the problem, which could vary from storm erosion repairs to
complete failure of a structure.
Emergency Maintenance
Maintenance after floods and other emergencies requires immediate mobilization. It can include
replanting and repairs to structures. Living systems are likely to need at least minor repairs after
emergencies. Following an emergency such as a flood, standing water may pose health risks
because of mosquitoes. Mosquito control should be considered if this becomes a problem.
For all installations, obstructions and debris deposited during storm events should be removed
immediately. Exceptions include debris that provides habitat and does not damage vegetation or
divert currents to, from, or in the SCM. In fact, because of the high quality habitat that can be
found in woody debris, careful re -positioning rather than complete removal may be desirable.
There may be instances where debris is even added. Such locations should be noted so that
this debris is not accidentally removed. Educating adjacent property owners about the habitat
benefits of debris and vegetation can decrease requests for removal.
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Debris & Litter Removal
Regularly removing debris and litter is well worth the effort and can be expected to help in the
following ways:
• Reduce the chance of clogging in outlet structures, trash racks, and other facility
components.
• Prevent damage to vegetated areas.
• Reduce mosquito breeding habitats.
• Maintain facility appearance.
• Reduce conditions for excessive surface algae.
• Reduce the likelihood of stagnant pool formation.
Special attention should be given to removing floating debris, which can clog outlet devices and
risers.
Sediment Removal & Disposal
Sediment gradually accumulates in many SCMs. For most SCMs, accumulated sediment must
eventually be removed. However, removal intervals vary so dramatically among facilities that no
"rules of thumb" are applicable. The specific setting of a SCM is important in determining how
often sediment must be removed. Important factors that determine rates of sedimentation
include the current and future land uses upstream and the presence of other sediment -trapping
SCMs upstream.
Before installing a SCM, designers should estimate the lifetime sediment accumulation that the
SCM will have to handle. Several time periods may be considered, representing expected
changes in land use in the watershed. To estimate sediment accumulation, first, an estimate of
the long term sediment load from upstream is needed, then an estimate of SCM sediment
removal efficiency (see Sections 3.0 and 4.0). The analysis of watershed sediment loss and
SCM efficiency can be expedited by using a sediment delivery computer model.
The frequency of sediment removal is then based on the sediment accumulation rate described
above versus the amount of sediment storage volume that is inherently provided in the SCM
without affecting treatment efficiency or stormwater storage volume. Again, the frequency of
sediment removal is SCM and site specific, and could be as frequent as every couple years, or
longer than 15-25 years. The volume of sediment needing to be removed and disposed of per
dredging cycle is the volume calculated above multiplied by any density or dewatering factors,
as appropriate.
Wet sediment is more difficult and expensive to remove than dry sediment. Ideally, the entire
facility can be drained and allowed to dry sufficiently so that heavy equipment can operate on
the bottom. Provisions for draining permanent pools should be incorporated in the design of
water impoundments where feasible. Also, low flow channels and outlets should be included in
all SCMs to bypass stormwater flow during maintenance. However, in many impoundments,
periodic rainfall keeps the sediment soft, preventing access by heavy equipment. In these
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cases, sediment may have to be removed from the shoreline by using backhoes, grade-alls, or
similar equipment.
Proper disposal of the sediment removed from a SCM must be considered. It is least expensive
if an onsite area or a nearby site has been set aside for the sediment. This area should be
located outside of the floodplain to prevent migration of the sediment if flooding occurs prior to
stabilization. If such a disposal area is not set aside, transportation and landfill tipping fees can
greatly increase the cost of maintaining the SCM, especially where disposal of wet sediment is
not allowed in the local landfill., Often, the material must be dewatered before disposal, which
again adds more cost and requires land area where wet material can be temporarily placed to
d ry.
Sediment removal is usually the largest single cost of maintaining a SCM facility so the
necessary funds should be allocated in advance. Since sediment removal costs are so site
specific and dependent on disposal plans, it is difficult to provide good estimates. Actual
estimates should be obtained during the design phase of the SCM from sediment removal
contractors based on the planned situation. The estimates should include: mobilization
expenses, sediment removal expenses, material transport expenses (if applicable), and
disposal expenses (if applicable).
Stability & Erosion Control
The best way to promote soil stability and erosion control is to maintain a healthy ground cover
in and around SCMs. Areas of bare soil quickly erode, potentially clogging the facility with
sediment and threatening its integrity. Therefore, bare areas must be re- stabilized as quickly as
possible. Newly seeded areas should be protected with mulch and/or an erosion mat that is
securely staked. For SCM's that rely on filtration, such as bioretention facilities, it is critical that
adjacent soils do not contaminate the selected media during or after construction. If the site is
not permanently stabilized with vegetation when the filter media is installed, the best design
practice is to specify sod or other robust erosion control practices for all slopes in and
immediately around the SCM.
Erosion more often occurs in or around the inlet and outlet of SCM facilities and should be
repaired as soon as possible.
The roots of woody growth such as young trees and bushes in embankments are destabilizing
and may result in premature failure if unchecked. Consistent mowing of the embankment
controls stray seedlings that take root. Woody growth, such as trees and bushes, further away
from the embankment should not pose a threat to the stability of the embankment and can
provide important runoff filtering benefits. Trees and bushes may be planted outside
maintenance and access areas.
Animal burrows also diminish the structural integrity of an embankment. Muskrats, in particular,
burrow tunnels up to 6 inches in diameter. Efforts should be made to control animal burrowing.
Burrows should be filled as soon as possible.
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Maintenance of Mechanical Components
SCMs may incorporate mechanical components that need periodic attention. For example,
valves, sluice gates, fence gates, locks, and access hatches should be functional at all times.
The routine inspection, exercising, and preventive maintenance on such mechanical
components should be included on a routine inspection and maintenance checklist.
Vegetation Maintenance
Vegetation maintenance is an important component of any maintenance program. The grasses
and plants in all SCMs, but particularly in vegetative SCMs such as filter strips, grass swales,
restored riparian buffers, bioretention facilities, and stormwater wetlands, require regular
attention. The development of distressed vegetation, bare spots, and rills indicates that a SCM
is not functioning properly. Problems can have many sources, such as:
• Excessive sediment accumulation, which clogs the soil pores and produces anaerobic
conditions.
• Nutrient deficiencies or imbalances, including pH and potassium.
• Water-logged conditions caused by reduced soil drainage or high seasonal water table.
• Competition from invasive weeds.
• Animal grazing
The soil in vegetated areas should be tested every other year and adjustments made to sustain
vigorous plant growth with deep, well-developed root systems. Aeration of soils is
recommended for filter strips and grassed swales where sediment accumulation rates are high.
Ideally, vegetative covers should be mown infrequently, allowing them to develop thick stands of
tall grass and other plant vegetation. Also, trampling from pedestrian traffic should be
prevented.
Areas immediately up and downstream of some SCM plant installations are more likely to
experience increased erosion. Properly designed, located, and transitioned installations
experience may reduce accelerated erosion. All erosion should be repaired immediately to
prevent spreading.
Table 2 below describes some typical vegetation maintenance. It is important to note that
specific requirements related to some management practices, such as those performed within
buffers, must be followed. In addition, any vegetation that poses threats to human safety,
buildings, fences, and other important structures should be addressed. Finally, vegetation
maintenance activities typically change as the project ages.
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Table 2: Vegetation Maintenance for SCMs
Replacement All dead plants should be removed and disposed of. Before vegetation that
of Dead has failed on a large scale is replaced, the cause of such failure should be
Plants investigated. If the cause can be determined, it should be eliminated before
any reinstallation.
The objective of fertilizing at a SCM is to secure optimum vegetative growth
rather than yield (often the objective with other activities such as farming).
Fertilization Infertile soils should be amended before installation and then fertilized
periodically thereafter. Fertilizer can be composed of minerals, organic
matter (manure), compost, green crops, or other materials.
Watering of the vegetation can often be required during the germination
and establishment of the vegetation, as well as occasionally to preserve the
Irrigation/ vegetation through drought conditions. This can typically be accomplished
Watering by pumping water retained in the SCM or from the stream, installing a
permanent irrigation system or frost -proof hose bib, or using portable water
trucks.
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Mulching should be used to maintain soil temperature and moisture, as
Mulching
well as site aesthetics. A half-inch layer is typically adequate. Ideally, mulch
should be removed before winter to prevent an infestation of rodents.
Weeding is often necessary in the first growing season, particularly if
herbaceous grasses are out -competing the young woody vegetation growth.
The need for weeding may be largely eliminated by minimizing the amount
Weeding
of seed used for temporary erosion control. Weeding may also be required
if, over time, invasive or undesirable species are entering the site and out -
competing plants that are specifically involved in the treatment of the
stormwater.
Cultivating/
Hoeing is often required to loosen overly compacted soil and eliminate
Hoeing
weeds that compete with the desirable vegetation.
Pruning
Pruning is used to trim to shape and remove dead wood. It can force single -
shoot shrubs and trees to assume a bushier configuration.
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Quality
Thinning dense vegetation may be necessary to thrive, to maintain open areas of
water as well as aesthetics, increase the vigor of individual specimens, to reduce
Thinning flow obstructions, and to increase the ability of maintenance staff to access the
entire SCM. Tall maturing trees, for the most part, have no place in a SCM (except
for buffers) and should be removed as soon as possible.
Saplings of tall trees planted in or near the SCM may require staking. Care
Staking should be taken not to damage the tree's roots with stakes. Stakes should be
kept in place for 6 to 18 months, and the condition of stakes and ties should
be checked periodically.
Wound The wounds on any trees found broken off or damaged should be dressed
Dressing following recommendations from a trained arborist.
Disease Based on monitoring observations, either insecticides or (preferably) organic means
Control of pest and fungal control should be used.
Fencing and signage should be installed to warn pedestrians and to prevent
damage due to trampling. These measures are often most necessary during early
Protection phases of installation but may be required at any time. Measures for controlling
from Animal human foot traffic include signs, fencing, floating log barriers, impenetrable bushes,
& Human ditches, paths, and piled brush. Wildlife damage is caused by the animals browsing,
Foot Traffic grazing, and rubbing the plants. The use of chemical wildlife repellents should be
avoided. Fences and meshes can be used to deter entry to the SCM. Tree tubes
can be used to prevent damage to individual specimens.
Mowing of perennial herbaceous grasses and wildflowers, especially once seed
heads have set, promotes redistribution of seed for this self-sustaining system.
Mowing Mowing should be carefully controlled, however, especially when performed for
aesthetics. As adjacent property owners and customers in general learn more about
SCMs, their vision of what is aesthetically pleasing can change. Grasses, in
healthy herbaceous stands, should never be mown more than once per year.
Maintenance of the Aquatic Environment
An important yet often overlooked aspect of SCMs that maintain a permanent pool is the need
to regularly monitor and manage conditions to promote a healthy aquatic environment. An
indicator of excess nutrients (a common problem) is excessive algae growth in the permanent
pool of water. Often, these problems can be addressed by encouraging the growth of more
desirable aquatic and semi -aquatic vegetation in and around the permanent pool. The plants
selected should be tolerant of varying water levels and have a high capacity to incorporate the
specific nutrients associated with the problem. Unchecked algae growth may result in aesthetic
and odor problems and algae -laden water can be washed downstream during rain contributing
to nuisance odors and stresses in downstream aquatic habitat.
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Insect Control
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Under the right conditions, ponded water can become a breeding ground for mosquitoes. Many
mosquito problems can be minimized through proper design and maintenance. The best control
technique for SCMs that maintain a permanent pool of water is to ensure that the design
discourages mosquito breeding habitat and encourages mosquito predators. Research at NC
State University has shown that Mosquitofish (Gambusia holbrooki) can be effective in the
control of mosquito populations in SCMs. This may include establishing combinations of deep
and shallow areas that encourage Mosquitofish as well as avoiding overhanging trees and other
vegetation that creates shade conducive to mosquito breeding and discourages dragonflies,
birds, bats, and other desirable predators. In larger basins, fish, which feed on mosquito larvae,
can be stocked. Additionally, splash aerators can be employed to prevent stagnant water,
however, this requires electricity at the site, increases maintenance costs and must be properly
designed so as to not decrease the settling efficiency of the SCM. Where feasible, SCMs may
incorporate a source of steady dry weather flow to reduce stagnant water.
Maintenance of Other Project Features
All other devices and features associated with the SCM should be monitored and maintained
appropriately. These additional items could affect the safety or aesthetics of the facility, which
can be as important if not more important than the operational efficiency of the facility. Such
items could include:
• Fences
• Access roads
• Trails
• Lighting
• Signage (e.g. no trespassing, emergency notification contact information, etc.)
• Nest boxes
• Platforms
• Watering system
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Wet Basin
Maintenance
Important maintenance procedures for wet ponds include:
1. Immediately after the wet pond is established, the plants on the vegetated shelf and
perimeter of the basin should be watered twice weekly if needed, until the plants become
established (commonly six weeks).
2. No portion of the wet pond should be fertilized after the first initial fertilization that is
required to establish the plants on the vegetated shelf.
3. Stable groundcover should be maintained in the drainage area to reduce the sediment
load to the wet pond.
4. If the pond must be drained for an emergency or to perform maintenance, the flushing of
sediment through the emergency drain should be minimized as much as possible.
5. Once a year, a dam safety expert should inspect the embankment.
After the wet pond is established, it should be inspected once every three months. Records of
operation and maintenance should be kept in a known set location and must be available upon
request. Inspection activities shall be performed as described in Table 4. Any problems that
are found shall be repaired immediately.
Table 4: Sample Operation and Maintenance Provisions for Wet Ponds
The entire BMP Trash/debris is present. Remove the trash/debris.
The perimeter of the wet pond
The inlet device: pipe or swale
C-3. Wet Pond
Areas of bare soil and/or
erosive gullies have formed
Vegetation is too short or too
long.
The pipe is clogged
Regrade the soil if necessary to
remove the gully, and then
plant a ground cover and water
until it is established. Provide
lime and a one-time fertilizer
application.
Maintain vegetation at a height
of approximately six inches.
Unclog the pipe. Dispose of
the sediment off-site.
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The pipe is cracked or Replace the pipe.
otherwise damaged.
Erosion is occurring in the Regrade the swale if necessary
swale. to smooth it over and provide
erosion control devices such as
reinforced turf matting or riprap
to avoid future problems with
erosion.
The forebay Sediment has accumulated to a
Search for the source of the
depth greater than the original
sediment and remedy the
design depth for sediment
problem if possible. Remove
storage.
the sediment and dispose of it
in a location where it will not
cause impacts to streams or
the BMP.
Erosion has occurred.
Provide additional erosion
protection such as reinforced
turf matting or riprap if needed
to prevent future erosion
problems.
Weeds are present. Remove the weeds, preferably
by hand. If pesticide is used,
wipe it on the plants rather than
spraying.
The vegetated shelf Best professional practices Prune according to best
show that pruning is needed to professional practices
maintain optimal plant health.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology,
disease, etc. Remedy the
problem and replace plants.
Provide a one-time fertilizer
application to establish the
ground cover if a soil test
indicates it is necessary.
Weeds are present. Remove the weeds, preferably
by hand. If pesticide is used,
wipe it on the plants rather than
spraying.
The main treatment area Sediment has accumulated to a Search for the source of the
depth greater than the original sediment and remedy the
design sediment storage depth. problem if possible. Remove
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the sediment and dispose of it
in a location where it will not
cause impacts to streams or
the BMP.
Algal growth covers over 50% Consult a professional to
of the area. remove and control the algal
growth.
Cattails, phragmites or other Remove the plants by wiping
invasive plants cover 50% of them with pesticide (do not
the basin surface. spray).
The embankment Shrubs have started to grow on Remove shrubs immediately.
the embankment.
Evidence of muskrat or beaver Use traps to remove muskrats
activity is present. and consult a professional to
remove beavers.
A tree has started to grow on Consult a dam safety specialist
the embankment. to remove the tree.
An annual inspection by an Make all needed repairs.
appropriate professional shows
that the embankment needs
repair.
The outlet device / The Clogging has occurred. Clean out the outlet device.
receiving water Dispose of the sediment off-
site.
The outlet device is damaged Repair or replace the outlet
device.
Erosion or other signs of Contact the local NC Division of
damage have occurred at the Water Quality Regional Office,
outlet. or the 401 Oversight Unit at
919-733-1786.
Floating wetland island (if Weeds or volunteer trees are Remove the weeds or trees.
applicable) growing on the mat.
The anchor cable is damaged, Restore the anchor cable to its
disconnected or missing. design state.
https://www.bae.ncsu.edu/extension/ext-publications/water/protecting/sea-grant-stormwater-
ponds-factsheet.pdf
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NORTH
AMERICAN
GREEN
CHANNEL ANALYSIS
> > > Swale 1
Name
Swale 1
Discharge
3.89
Peak Flow Period
0.2
Channel Slope
0.04
Channel Bottom Width
3
Left Side Slope
3
Right Side Slope
3
Low Flow Liner
Retardence Class
C 6-12 in
Vegetation Type
Mix (Sod and Bunch)
Vegetation Density
Good 75-95%
Soil Type
Clay Loam
5150
ECMDS 6.0
North American Green
5401 St. Wendel-Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v6.0
Phase Reach Discharge Velocity Normal Mannings N Permissable Calculated Safety Remarks Staple
Depth Shear Stress Shear Stress Factor Pattern
5150 Straight 3.89 cfs 2.4 ft/s 0.39 ft 0.055 1.75 11bs/ft2 0.97 11bs/ft2 1.8 STABLE E
Unvegetated
Unreinforced Vegetation - Class C - Mix (Sod & Bunch) - Good 75-95%
Phase Reach Discharge Velocity Normal Mannings N Permissable Calculated Safety Remarks Staple
Depth Shear Stress Shear Stress Factor Pattern
lnreinforced Straight 3.89 cfs 1.49 ft/s 0.56 ft 0.109 4.2 lbs/ft2 1.4 lbs/ft2 3.01 STABLE
Vegetation
Underlying Straight 3.89 cfs 1.49 ft/s 0.56 ft -- 0.05 lbs/ft2 0.01 11bs/ft2 6.93 STABLE
Substrate
Page 88 of 93
https://ecmds.com/project/l38008/channel-analysis/151916/show 1/1

10/17/2018
NORTH
AMERICAN
GREEN
CHANNEL ANALYSIS
> > > Swale 2
Name
Swale 2
Discharge
1.89
Peak Flow Period
0.2
Channel Slope
0.04
Channel Bottom Width
3
Left Side Slope
3
Right Side Slope
3
Low Flow Liner
Retardence Class
D 2-6 in
Vegetation Type
Mix (Sod and Bunch)
Vegetation Density
Good 75-95%
Soil Type
Clay Loam
5150
ECMDS 6.0
North American Green
5401 St. Wendel-Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v6.0
Phase Reach Discharge Velocity Normal Mannings N Permissable Calculated Safety Remarks Staple
Depth Shear Stress Shear Stress Factor Pattern
5150 Straight 1.89 cfs 1.92 ft/s 0.26 ft 0.055 1.75 11bs/ft2 0.65 lbs/ft2 2.69 STABLE E
Unvegetated
Unreinforced Vegetation - Class D - Mix (Sod & Bunch) - Good 75-95%
Phase Reach Discharge Velocity Normal Mannings N Permissable Calculated Safety Remarks Staple
Depth Shear Stress Shear Stress Factor Pattern
lnreinforced Straight 1.89 cfs 1.29 ft/s 0.36 ft 0.098 3.33 11bs/ft2 0.9 11bs/ft2 3.71 STABLE
Vegetation
Underlying Straight 1.89 cfs 1.29 ft/s 0.36 ft -- 0.05 lbs/ft2 0.01 11bs/ft2 8.82 STABLE
Substrate
Page 89 of 93
https://ecmds.com/project/l38008/channel-analysis/151918/show 1/1

10/17/2018
NORTH
AMERICAN
GREEN
CHANNEL ANALYSIS
> > > Swale 3
Name
Swale 3
Discharge
4.01
Peak Flow Period
0.2
Channel Slope
0.058
Channel Bottom Width
3
Left Side Slope
3
Right Side Slope
3
Low Flow Liner
Retardence Class
D 2-6 in
Vegetation Type
Mix (Sod and Bunch)
Vegetation Density
Good 75-95%
Soil Type
Clay Loam
5150
ECMDS 6.0
North American Green
5401 St. Wendel-Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v6.0
Phase Reach Discharge Velocity Normal Mannings N Permissable Calculated Safety Remarks Staple
Depth Shear Stress Shear Stress Factor Pattern
5150 Straight 4.01 cfs 2.76 ft/s 0.36 ft 0.055 1.75 11bs/ft2 1.29 lbs/ft2 1.35 STABLE E
Unvegetated
Unreinforced Vegetation - Class D - Mix (Sod & Bunch) - Good 75-95%
Phase Reach Discharge Velocity Normal Mannings N Permissable Calculated Safety Remarks Staple
Depth Shear Stress Shear Stress Factor Pattern
lnreinforced Straight 4.01 cfs 2.31 ft/s 0.41 ft 0.071 3.33 11bs/ft2 1.48 lbs/ft2 2.24 STABLE
Vegetation
Underlying Straight 4.01 cfs 2.31 ft/s 0.41 ft -- 0.05 lbs/ft2 0.02 11bs/ft2 2.78 STABLE
Substrate
Page 90 of 93
https://ecmds.com/project/l38008/channel-analysis/151919/show 1/1

DRAINAGE AREA PLANS
Page 91 of 93

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