12208 Hydro Report

HYDROLOGY AND EROSION CONTROL STUDY
FOR
Mitchell County Middle School
5085 S. NC Hwy 226,
Bakersville, NC 28705
PIN: 0872-70-6960
CDC project No. 12208
OWNER
Mitchell County
72 Ledger School Rd
Bakersville, NC 28705
Contact: Kim Hodshon,
Executive Director Career Technical Education/Facilities/Athletics
[e-mail]
828-766-3437
RNCTFvF,F,R
Michael Cain, PE
o
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SEAL
o
047788
:-4-/C FNGINE�� °P��
' �S'gEL.1., p�ti
August 30, 2022
Rev: Sept. 23, 2022
'4D Civil
Design
Concepts, PA
168 Patton Avenue, Asheville, NC 28801
828-252-5388

TABLE OF CONTENTS
ITEM/DESCRIPTION
PAGE NO.
1.0 Proj ect Narrative........................................................................................... 1
2.0 Erosion Controls...........................................................................................2
3.0 Stormwater Analysis.................................................................................... 3
3.1 Water Quality Volume..................................................................... 3
3.2 Water Quality Drawdown................................................................ 3
3.3 Water Quantity................................................................................. 3
APPENDICES
Appendix A
FEMA FMMette Map & USGS Topo Map
Appendix B
USDA NRCS Soils Report
Appendix C
NOAA Rainfall Data
Appendix D
Existing and Proposed Drainage Area Maps
Appendix E
Skimmer Basin Design Calculations
Appendix F
Flowrate Calculations and Channel Protection
Appendix G
Rip -rap Calculations
Appendix H
StreamStats Report
Appendix I
Storm Drainage Calculations
Appendix J
Wet Pond Forebay and Permanent Pool Volume Calculations
Appendix K
24-Hour WQV Drawdown HydroCAD Output Report
Appendix L
1-Year Storm Event HydroCAD Output Report
Appendix M
10-Year Storm Event HydroCAD Output Report
Appendix N
50-Year Storm Event HydroCAD Output Report

Hydrology and Erosion Control Study
Mitchell County Middle School
1.0 INTRODUCTION
Page 1
The project will consist of the construction of a new middle school with associated parking, road
improvements, utilities, and supporting infrastructure. The project is located at 5085 South NC Hwy
226 in an unincorporated area of Mitchell County, NC. The site is immediately northwest of the
intersection of Ledger School Rd and NC 226. The parcel is 14.94 acres. The project will disturb
approximately 12.3 acres. Adjacent to the site are mostly single-family home parcels, however to the
north and east are Mitchell County Schools facilities and Mitchell Senior Citizens Center. The parcel
previously had one home. The remainder of the tract was utilized as agricultural / pastureland.
Majority of slopes on the existing site range from 5 to 25%. A FEMA FIRMette and USGS Topo map
are included in Appendix A.
Site drainage generally flows into a central draw, and then southeast into an unnamed tributary stream
of Cranberry Branch on the east side of the site. Per NCDEQ surface water classification map,
Cranberry Branch (stream index: 7-2-46-2) has a " C;Tf' classification and is part of the French Broad
River basin. The project area is not within the 100-year floodplain.
Currently there are no detention or water quality facilities on site. It is the intent of this report to
demonstrate that the proposed stormwater management facilities will comply with water quantity and
quality controls as regulated by the state of North Carolina. At the time of this report, there were no
known drainage concerns related to this site or downstream properties.
2.0 EROSION CONTROLS
The parcel consists of 14.94 acres. Approximately 12.3 acres will be disturbed by construction
activities. A USDA NRCS Soils Report is included in Appendix B. All erosion control measures
proposed have been designed to the 10-year storm event. See Appendix C for rainfall amounts used in
this study. Drainage area maps can be found in Appendix D.
Erosion controls will be completed in a three-phase approach. Refer to the construction plans for
further detail on the erosion control measures. Phase 1 will include site clearing and rough grading.
During this phase, erosion control devices will consist of construction entrances, perimeter silt fences,
temporary ditches, bypass piping, and a skimmer basin. Calculations to support the sizing of the
skimmer basin are present in Appendix E.
Phase 2 will include site development and utility installation. During this phase inlet protection will be
added as construction progresses. Reinforcement fabrics will be installed in permanent ditches as
needed. The skimmer basin will be converted into a detention basin as construction progresses. Rip
rap aprons will be added to pipe outfalls. Calculations associated with channel stabilization and outlet
protection are provided in Appendix F.
Phase 3 will consist of site stabilization. Construction of pavement, building and installation of
landscaping or grassing will aid in site stabilization. Outlet protection measures in the form of rip -rap
aprons will be installed to prevent scouring. Calculations associated with outlet protection are provided
in Appendix G. Maintenance of all erosion control measures shall continue until the site is fully
stabilized. All remaining erosion control measures will be removed when no longer needed.

Hydrology and Erosion Control Study
Mitchell County Middle School
3.0 STORMWATER ANALYSIS
Page 2
SCS-TR55 methodology has been incorporated in the peak runoff analysis and design of the
stormwater treatment/detention facilities. Stormwater was modeled using HydroCAD, Version 10.20-
2d. StreamStats reports have been provided in Appendix H to support the sizing of all stream culverts.
All conveyance pipes have been sized to handle a 25-year storm event (see Appendix I). Stormwater
flows will be collected by curb and gutter, asphalt swales, stormwater inlets, and piping and discharged
into a wet pond for treatment.
3.1 Water Quality Volume: The state of North Carolina requires that the project provide enough
water quality volume (WQv) to treat a design storm depth of 1 inch on the developed site. Per NCDEQ
minimum design criteria for wet ponds, the main pool surface area and volume can be found using the
SA/DA (minimum surface area to drainage area ratio) Tables with Average Depth Method. See
supporting calculations for wet pond `A' below.
Wet Pond `A'
Impervious Fraction:
Total Drainage Area (DA) to WQv Basin = 7.56 Acres
Total Impervious Area to WQv Basin = 4.18 Acres
Impervious Fraction (IA) = 0.55
Per NCDEQ SCM C-3, the average depth of the permanent pool must be greater than or equal to 3.0-ft.
Volume of Permanent Pool (VPP) Provided = 32,541 CF
Surface Area of Permanent Pool (SA) Provided = 8,909 SF
See Appendix J for pond volume calculations.
NCDEQ SCM C-3 (MDC 2) Equation 2 can be used to establish average depth (Davg):
Davg = VPP/SA
Davg = 32,541/8,909 = 3.65 FT
3.65 FT > 3.0 FT hence Davg provided is acceptable

Hydrology and Erosion Control Study
Mitchell County Middle School
NCDEQ Sturmwuater Design Manual
Page 3
F. ,v
Table I: Pied= nrand Moun fain SAIDA Table (Adapfed from Oriscorl, 1986)
10%
0.51
0.43
0.37
0.30
0.27
0.25
20%
0.64
0.69
0.61
0.51
0.44
0.40
30%
1.17
0.94
0_94
0.72
0.6 t
0.56
40%
1.61
1_24
1.09
0.91
0.78
0_71
50%
1.79
f _5 t
1.31
1.13
0.95
0.87
■
60%
2.09
1.77
t _49
1.31
1.12
1.03
70%
2.51
2.09
t _BO
1.55
1.34
1.17
80%
2.92
2.41
2.07
1.82
1.62
1.40
go%
3.25
2.64
2.31
2.04
1.84
1.59
100%
3.55
2.79
2.52
2.34
2.04
1_75
When using a Dag of 3.65, an interpolated SA/DA ratio per NCDEQ SCM C-3 Table 1 for 55%
impervious cover is 1.75 (expressed as a %).
Minimum surface area required for the permanent pool using known drainage area and SA/DA ratio:
SA = 1.74 / 100 * 7.56 AC * 43,560 SF = 5,730 SF
Proposed Surface Area of Permanent Pool (SA) = 8,909 SF
8909 SF > 5,730 SF hence SA provided is acceptable.
Forebay volume required to be 15-20% of permanent pool volume per NCDEQ SCM C-3 MDC 5:
Permanent pool volume provided = 46,604 CF
32,541 * 0.15 = 4,881
32,541 * 0.20 = 6,508
Acceptable volume range: 4,881 CF - 6,508 CF
Provided volume: 6,404
Provided volume is within acceptable range.
Required water quality volume for 1-in storm depth utilizing the simple method:
Total Area to WQv Basin = 7.56 Acres
Runoff Coefficient (Rv) _ .05+0.9 x IA
Runoff Coefficient (Rv) = 0.55
WQv = 3630 x 1-in x 0.55 x 7.56-ac = 15,094 CF

Hydrology and Erosion Control Study
Mitchell County Middle School
Wet Pond `A' temporary pool provides 15,546 CF of storage below the overflow weir.
15,546 CF > 15,094 hence temporary pool volume provided is acceptable.
Page 4
3.2 Water Quality Drawdown: The state of North Carolina requires that the provided WQv
discharge over a period between two and five days. To determine the drawdown period for the WQv,
the modeled pond was staged to the equivalent storage elevation and allowed to discharge through the
outlet control structure orifice(s). See Site Development Plans for details of the outlet control structure.
Based on the HydroCAD output report provided in Appendix K, the wet pond `A' will drawdown in
approximately 57 Hours.
3.3 Water Quantity: Peak attenuation of storm events larger than that required for water quality is
not required by Mitchell County or the State of North Carolina. However, the proposed wet pond has
been designed to discharge the one-year, 24-hour storm in a manner that minimizes hydrologic impacts
to the receiving stream. See Appendices L, M and N for HydroCAD output reports of the 1, 10, and
50-year storm events respectively. The wet pond can safely convey a 50 year — 24 hour storm event.
Freeboard elevations have been provided in table 3.3 below.
Table 3.3: Stormwater Staging Analysis -Wet Pond A
Modeled
Storm
Event
Staging
Elevation
feet
Top of Stormwater
Detention Basin
feet
Freeboard
feet
1-Year
2726.8
2729.0
2.2
10-Year
2727.5
2729.0
1.5
50-Year
2727.7
2729.0
1.3

APPENDIX A
FEMA FIRM Map
USGS Topo Map

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USGS TOPO

APPENDIX B
USDA NRCS Soils Report

USDA United States
Department of
Agriculture
N RCS
Natural
Resources
Conservation
Service
A product of the National
Cooperative Soil Survey,
a joint effort of the United
States Department of
Agriculture and other
Federal agencies, State
agencies including the
Agricultural Experiment
Stations, and local
participants
Custom Soil Resource
Report for
Mitchell County,
North Carolina
Mitchell County Middle School
June 2, 2022

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

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

Contents
Preface....................................................................................................................
2
SoilMap..................................................................................................................
5
SoilMap................................................................................................................6
Legend..................................................................................................................7
MapUnit Legend..................................................................................................
8
MapUnit Descriptions..........................................................................................
8
Mitchell County, North Carolina......................................................................
10
BdA—Bandana sandy loam, 0 to 3 percent slopes, occasionally flooded..
10
EcC—Evard-Cowee complex, central mountains, 8 to 15 percent slopes..
11
EcD—Evard-Cowee complex, central mountain, 15 to 30 percent
slopes, stony.........................................................................................13
EdE—Evard-Cowee complex, central mountain, 30 to 50 percent
slopes, stony.........................................................................................15
SaB—Saunook silt loam, 2 to 8 percent slopes ..........................................
17
ScC—Saunook silt loam, 8 to 15 percent slopes, stony..............................19
Ud—Udorthents, loamy...............................................................................20
References............................................................................................................
22

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.

399100
35° 58' 5" N
35° 5750" N
Custom Soil Resource Report
Soil Map
399150 399200 399250 399300
399100 399150 399200 399250 399300
m
Map Scale: 1:2,200 if printed on A portrait (8.5" x 11") sheet.
Meters N
0 30 EO 120 180
Feet
0 100 200 400 600
Map projection: Web Mercator Comer coordinates: WGS84 Edge tics: UTM Zone 17N WGS84
6
in
399400
35° 58' 5" N
0
r
0
r
35° 5750" N
399400
in
o�

MAP LEGEND
Area of Interest (AOI)
0
Area of Interest (AOI)
Soils
0
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
Special
Point Features
Iwo
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
�i
Gravelly Spot
Landfill
A.
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
oa
Sodic Spot
Custom Soil Resource Report
MAP INFORMATION
Spoil Area
The soil surveys that comprise your AOI were mapped at
1:12,000.
Stony Spot
Very Stony Spot
Warning: Soil Map may not be valid at this scale.
Wet Spot
Enlargement of maps beyond the scale of mapping can cause
Other
misunderstanding of the detail of mapping and accuracy of soil
�-
Special Line Features
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
Water Features
scale.
Streams and Canals
Transportation
Please rely on the bar scale on each map sheet for map
E F
Rails
measurements.
. 0
Interstate Highways
Source of Map: Natural Resources Conservation Service
US Routes
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Major Roads
Local Roads
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
Background
distance and area. A projection that preserves area, such as the
Aerial Photography
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Mitchell County, North Carolina
Survey Area Data: Version 16, Jan 21, 2022
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Nov 16, 2019—May
7, 2020
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
7

Custom Soil Resource Report
Map Unit Legend
Map Unit Symbol
Map Unit Name
Acres in AOI
Percent of AOI
BdA
Bandana sandy loam, 0 to 3
3.0
19.7%
percent slopes, occasionally
flooded
EcC
Evard-Cowee complex, central
4.0
26.1 %
mountains, 8 to 15 percent
slopes
EcD
Evard-Cowee complex, central
1.6
10.6%
mountain, 15 to 30 percent
slopes, stony
EdE
Evard-Cowee complex, central
0.3
1.7%
mountain, 30 to 50 percent
slopes, stony
SaB
Saunook silt loam, 2 to 8
3.0
19.8%
percent slopes
Scc
Saunook silt loam, 8 to 15
2.3
14.8%
percent slopes, stony
Ud
Udorthents, loamy
1.1
7.4%
Totals for Area of Interest
16.4
100.0%
Map Unit Descriptions
The map units delineated on the detailed soil maps in a soil survey represent the
soils or miscellaneous areas in the survey area. The map unit descriptions, along
with the maps, can be used to determine the composition and properties of a unit.
A map unit delineation on a soil map represents an area dominated by one or more
major kinds of soil or miscellaneous areas. A map unit is identified and named
according to the taxonomic classification of the dominant soils. Within a taxonomic
class there are precisely defined limits for the properties of the soils. On the
landscape, however, the soils are natural phenomena, and they have the
characteristic variability of all natural phenomena. Thus, the range of some
observed properties may extend beyond the limits defined for a taxonomic class.
Areas of soils of a single taxonomic class rarely, if ever, can be mapped without
including areas of other taxonomic classes. Consequently, every map unit is made
up of the soils or miscellaneous areas for which it is named and some minor
components that belong to taxonomic classes other than those of the major soils.
Most minor soils have properties similar to those of the dominant soil or soils in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
management. These are called contrasting, or dissimilar, components. They
generally are in small areas and could not be mapped separately because of the
scale used. Some small areas of strongly contrasting soils or miscellaneous areas

Custom Soil Resource Report
are identified by a special symbol on the maps. If included in the database for a
given area, the contrasting minor components are identified in the map unit
descriptions along with some characteristics of each. A few areas of minor
components may not have been observed, and consequently they are not
mentioned in the descriptions, especially where the pattern was so complex that it
was impractical to make enough observations to identify all the soils and
miscellaneous areas on the landscape.
The presence of minor components in a map unit in no way diminishes the
usefulness or accuracy of the data. The objective of mapping is not to delineate
pure taxonomic classes but rather to separate the landscape into Iandforms or
Iandform segments that have similar use and management requirements. The
delineation of such segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, however,
onsite investigation is needed to define and locate the soils and miscellaneous
areas.
An identifying symbol precedes the map unit name in the map unit descriptions.
Each description includes general facts about the unit and gives important soil
properties and qualities.
Soils that have profiles that are almost alike make up a soil series. Except for
differences in texture of the surface layer, all the soils of a series have major
horizons that are similar in composition, thickness, and arrangement.
Soils of one series can differ in texture of the surface layer, slope, stoniness,
salinity, degree of erosion, and other characteristics that affect their use. On the
basis of such differences, a soil series is divided into soil phases. Most of the areas
shown on the detailed soil maps are phases of soil series. The name of a soil phase
commonly indicates a feature that affects use or management. For example, Alpha
silt loam, 0 to 2 percent slopes, is a phase of the Alpha series.
Some map units are made up of two or more major soils or miscellaneous areas.
These map units are complexes, associations, or undifferentiated groups.
A complex consists of two or more soils or miscellaneous areas in such an intricate
pattern or in such small areas that they cannot be shown separately on the maps.
The pattern and proportion of the soils or miscellaneous areas are somewhat similar
in all areas. Alpha -Beta complex, 0 to 6 percent slopes, is an example.
An association is made up of two or more geographically associated soils or
miscellaneous areas that are shown as one unit on the maps. Because of present
or anticipated uses of the map units in the survey area, it was not considered
practical or necessary to map the soils or miscellaneous areas separately. The
pattern and relative proportion of the soils or miscellaneous areas are somewhat
similar. Alpha -Beta association, 0 to 2 percent slopes, is an example.
An undifferentiated group is made up of two or more soils or miscellaneous areas
that could be mapped individually but are mapped as one unit because similar
interpretations can be made for use and management. The pattern and proportion
of the soils or miscellaneous areas in a mapped area are not uniform. An area can
be made up of only one of the major soils or miscellaneous areas, or it can be made
up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include miscellaneous areas. Such areas have little or no soil
material and support little or no vegetation. Rock outcrop is an example.

Custom Soil Resource Report
Mitchell County, North Carolina
BdA—Bandana sandy loam, 0 to 3 percent slopes, occasionally flooded
Map Unit Setting
National map unit symbol: Icrj
Elevation: 1,070 to 2,280 feet
Mean annual precipitation: 48 to 60 inches
Mean annual air temperature: 46 to 57 degrees F
Frost -free period: 116 to 170 days
Farmland classification: Prime farmland if drained
Map Unit Composition
Bandana, occasionally flooded, and similar soils: 80 percent
Minor components: 20 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Bandana, Occasionally Flooded
Setting
Landform: Flood plains
Down -slope shape: Linear
Across -slope shape: Linear
Parent material: Loamy alluvium over sandy and gravelly alluvium
Typical profile
A - 0 to 8 inches: sandy loam
Bw - 8 to 37 inches: sandy loam
C - 37 to 80 inches: very gravelly sand
Properties and qualities
Slope: 0 to 3 percent
Depth to restrictive feature: 20 to 40 inches to strongly contrasting textural
stratification
Drainage class: Somewhat poorly drained
Runoff class: Very low
Capacity of the most limiting layer to transmit water (Ksat): High (2.00 to 6.00
in/hr)
Depth to water table: About 18 to 24 inches
Frequency of flooding: NoneOccasional
Frequency of ponding: Rare
Available water supply, 0 to 60 inches: Low (about 5.0 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 3w
Hydrologic Soil Group: A/D
Hydric soil rating: No
Minor Components
Ela, undrained
Percent of map unit. 5 percent
Landform: Depressions on flood plains
Down -slope shape: Concave, linear
Across -slope shape: Concave
10

Custom Soil Resource Report
Hydric soil rating: Yes
Dillard, rarely flooded
Percent of map unit: 5 percent
Landform: Stream terraces
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Base slope
Down -slope shape: Concave
Across -slope shape: Linear
Hydric soil rating: No
Thurmont
Percent of map unit: 5 percent
Landform: Drainageways
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Base slope
Down -slope shape: Concave
Across -slope shape: Linear
Hydric soil rating: No
Fontaflora, occasionally flooded
Percent of map unit: 5 percent
Landform: Flood plains
Down -slope shape: Linear
Across -slope shape: Linear
Hydric soil rating: No
EcC—Evard-Cowee complex, central mountains, 8 to 15 percent slopes
Map Unit Setting
National map unit symbol: 2xpd6
Elevation: 2,260 to 3,790 feet
Mean annual precipitation: 44 to 53 inches
Mean annual air temperature: 46 to 57 degrees F
Frost -free period: 125 to 172 days
Farmland classification: Farmland of statewide importance
Map Unit Composition
Evard, central mountains, and similar soils: 55 percent
Cowee, central mountains, and similar soils: 30 percent
Minor components: 15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Evard, Central Mountains
Setting
Landform: Mountain slopes, ridges
Landform position (two-dimensional): Backslope, summit
Landform position (three-dimensional): Upper third of mountainflank, mountaintop,
side slope, crest
Down -slope shape: Convex, linear
11

Custom Soil Resource Report
Across -slope shape: Linear, convex
Parent material: Residuum weathered from amphibolite and/or hornblende gneiss
Typical profile
A - 0 to 5 inches: loam
Bt - 5 to 32 inches: clay loam
BC - 32 to 45 inches: loam
C - 45 to 80 inches: loam
Properties and qualities
Slope: 8 to 15 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high
(0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: High (about 9.7 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: B
Hydric soil rating: No
Description of Cowee, Central Mountains
Setting
Landform: Mountain slopes, ridges
Landform position (two-dimensional): Summit, backslope
Landform position (three-dimensional): Upper third of mountainflank, mountaintop,
side slope, crest
Down -slope shape: Convex, linear
Across -slope shape: Linear, convex
Parent material: Residuum weathered from amphibolite and/or hornblende gneiss
Typical profile
A - 0 to 5 inches: loam
Bt - 5 to 38 inches: gravelly clay loam
Cr - 38 to 80 inches: bedrock
Properties and qualities
Slope: 8 to 15 percent
Depth to restrictive feature: 20 to 40 inches to paralithic bedrock
Drainage class: Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat): Very low to moderately
low (0.00 to 0.06 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: Low (about 5.4 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 3e
12

Custom Soil Resource Report
Hydrologic Soil Group: C
Hydric soil rating: No
Minor Components
Saunook, central mountains
Percent of map unit: 10 percent
Landform: Coves, fans, drainageways
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Mountainbase, base slope
Down -slope shape: Convex, linear
Across -slope shape: Convex, linear
Hydric soil rating: No
Clifton
Percent of map unit: 5 percent
Landform: Hillslopes, ridges
Landform position (two-dimensional): Backslope, summit
Landform position (three-dimensional): Side slope, interfluve
Down -slope shape: Convex
Across -slope shape: Linear
Hydric soil rating: No
EcD—Evard-Cowee complex, central mountain, 15 to 30 percent slopes,
stony
Map Unit Setting
National map unit symbol: 2vx2g
Elevation: 1,990 to 4,490 feet
Mean annual precipitation: 41 to 57 inches
Mean annual air temperature: 46 to 57 degrees F
Frost -free period: 137 to 176 days
Farmland classification: Farmland of local importance
Map Unit Composition
Evard, central mountain, stony, and similar soils: 60 percent
Cowee, central mountain, stony, and similar soils: 30 percent
Minor components: 10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Evard, Central Mountain, Stony
Setting
Landform: Mountain slopes, ridges
Landform position (two-dimensional): Backslope, summit
Landform position (three-dimensional): Upper third of mountainflank, mountaintop,
side slope, crest
Down -slope shape: Convex, linear
Across -slope shape: Linear, convex
13

Custom Soil Resource Report
Parent material: Residuum weathered from amphibolite and/or hornblende gneiss
Typical profile
A - 0 to 5 inches: loam
Bt - 5 to 32 inches: clay loam
BC - 32 to 45 inches: loam
C - 45 to 80 inches: loam
Properties and qualities
Slope: 15 to 30 percent
Surface area covered with cobbles, stones or boulders: 0.1 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Well drained
Runoff class: High
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high
(0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: High (about 9.7 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 4e
Hydrologic Soil Group: B
Hydric soil rating: No
Description of Cowee, Central Mountain, Stony
Setting
Landform: Mountain slopes, ridges
Landform position (two-dimensional): Summit, backslope
Landform position (three-dimensional): Upper third of mountainflank, mountaintop,
side slope, crest
Down -slope shape: Convex, linear
Across -slope shape: Linear, convex
Parent material: Residuum weathered from amphibolite and/or hornblende gneiss
Typical profile
A - 0 to 5 inches: sandy loam
Bt - 5 to 38 inches: gravelly clay loam
Cr - 38 to 80 inches: bedrock
Properties and qualities
Slope: 15 to 30 percent
Surface area covered with cobbles, stones or boulders: 0.1 percent
Depth to restrictive feature: 20 to 40 inches to paralithic bedrock
Drainage class: Well drained
Runoff class: High
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 supply, 0 to 60 inches: Low (about 5.2 inches)
Interpretive groups
Land capability classification (irrigated): None specified
14

Custom Soil Resource Report
Land capability classification (nonirrigated): 4s
Hydrologic Soil Group: C
Hydric soil rating: No
Minor Components
Clifton
Percent of map unit: 6 percent
Landform: Ridges, hillslopes
Landform position (two-dimensional): Summit, backslope
Landform position (three-dimensional): Interfluve, side slope
Down -slope shape: Convex
Across -slope shape: Linear
Hydric soil rating: No
Saunook
Percent of map unit: 4 percent
Landform: Toes on drainageways
Landform position (two-dimensional): Footslope
Landform position (three-dimensional): Mountainbase, upper third of
mountainflank, base slope, head slope
Down -slope shape: Linear, concave
Across -slope shape: Concave
Hydric soil rating: No
EdE—Evard-Cowee complex, central mountain, 30 to 50 percent slopes,
stony
Map Unit Setting
National map unit symbol: 2wldc
Elevation: 1,980 to 4,530 feet
Mean annual precipitation: 42 to 55 inches
Mean annual air temperature: 46 to 57 degrees F
Frost -free period: 124 to 205 days
Farmland classification: Not prime farmland
Map Unit Composition
Evard, central mountain, stony, and similar soils: 55 percent
Cowee, central mountain, stony, and similar soils: 35 percent
Minor components: 10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Evard, Central Mountain, Stony
Setting
Landform: Mountain slopes, ridges
Landform position (two-dimensional): Backslope, summit
Landform position (three-dimensional): Upper third of mountainflank, mountaintop,
side slope, crest
15

Custom Soil Resource Report
Down -slope shape: Convex, linear
Across -slope shape: Linear, convex
Parent material: Affected by soil creep in the upper solum over residuum
weathered from igneous and metamorphic rock
Typical profile
A - 0 to 5 inches: loam
Bt - 5 to 32 inches: clay loam
BC - 32 to 45 inches: loam
C - 45 to 80 inches: loam
Properties and qualities
Slope: 30 to 50 percent
Surface area covered with cobbles, stones or boulders: 0.1 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Well drained
Runoff class: High
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high
(0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: High (about 9.7 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 6e
Hydrologic Soil Group: B
Hydric soil rating: No
Description of Cowee, Central Mountain, Stony
Setting
Landform: Mountain slopes, ridges
Landform position (two-dimensional): Summit, backslope
Landform position (three-dimensional): Upper third of mountainflank, mountaintop,
side slope, crest
Down -slope shape: Convex, linear
Across -slope shape: Linear, convex
Parent material: Affected by soil creep in the upper solum over residuum
weathered from igneous and metamorphic rock
Typical profile
A - 0 to 5 inches: sandy loam
Bt - 5 to 38 inches: gravelly clay loam
Cr - 38 to 80 inches: bedrock
Properties and qualities
Slope: 30 to 50 percent
Surface area covered with cobbles, stones or boulders: 0.1 percent
Depth to restrictive feature: 20 to 40 inches to paralithic bedrock
Drainage class: Well drained
Runoff class: High
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
it.

Custom Soil Resource Report
Frequency of ponding: None
Available water supply, 0 to 60 inches: Low (about 5.2 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 6s
Hydrologic Soil Group: C
Hydric soil rating: No
Minor Components
Clifton, moderately eroded
Percent of map unit. 8 percent
Landform: Ridges, hillslopes
Landform position (two-dimensional): Summit, backslope
Landform position (three-dimensional): Interfluve, side slope
Down -slope shape: Convex
Across -slope shape: Linear
Hydric soil rating: No
Saunook, stony
Percent of map unit. 2 percent
Landform: Toes on drainageways
Landform position (two-dimensional): Footslope
Landform position (three-dimensional): Mountainbase, upper third of
mountainflank, base slope, head slope
Down -slope shape: Linear, concave
Across -slope shape: Concave
Hydric soil rating: No
Rock outcrop
Percent of map unit. 0 percent
Hydric soil rating: No
SaB—Saunook silt loam, 2 to 8 percent slopes
Map Unit Setting
National map unit symbol: 2xpcy
Elevation: 1,980 to 3,720 feet
Mean annual precipitation: 42 to 52 inches
Mean annual air temperature: 46 to 57 degrees F
Frost -free period: 125 to 172 days
Farmland classification: All areas are prime farmland
Map Unit Composition
Saunook and similar soils: 80 percent
Minor components: 20 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
17

Custom Soil Resource Report
Description of Saunook
Setting
Landform: Coves, fans, drainageways
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Mountainbase, base slope
Down -slope shape: Convex, linear
Across -slope shape: Convex, linear
Parent material: Colluvium derived from igneous and metamorphic rock
Typical profile
Ap - 0 to 10 inches: silt loam
BA - 10 to 15 inches: loam
Bt1 - 15 to 25 inches: silt loam
Bt2 - 25 to 38 inches: silt loam
Bt3 - 38 to 50 inches: gravelly loam
BC - 50 to 80 inches: very cobbly sandy loam
Properties and qualities
Slope: 2 to 8 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high
(0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: Moderate (about 8.3 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 2e
Hydrologic Soil Group: B
Hydric soil rating: No
Minor Components
Bandana, occasionally flooded
Percent of map unit. 8 percent
Landform: Flood -plain steps
Landform position (three-dimensional): Rise
Down -slope shape: Linear
Across -slope shape: Linear
Hydric soil rating: No
Dillsboro
Percent of map unit. 7 percent
Landform: Stream terraces, coves
Landform position (two-dimensional): Toeslope, footslope
Landform position (three-dimensional): Mountainbase, base slope
Down -slope shape: Convex, concave
Across -slope shape: Linear, concave
Hydric soil rating: No
Thunder
Percent of map unit. 5 percent
18

Custom Soil Resource Report
Landform: Coves, drainageways, fans
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Mountainbase, base slope
Down -slope shape: Concave, linear
Across -slope shape: Concave, linear
Hydric soil rating: No
ScC—Saunook silt loam, 8 to 15 percent slopes, stony
Map Unit Setting
National map unit symbol: 2xpcz
Elevation: 1,990 to 4,510 feet
Mean annual precipitation: 41 to 56 inches
Mean annual air temperature: 46 to 57 degrees F
Frost -free period: 125 to 172 days
Farmland classification: Farmland of local importance
Map Unit Composition
Saunook and similar soils: 80 percent
Minor components: 20 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Saunook
Setting
Landform: Coves, drainageways, fans
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Mountainbase, base slope
Down -slope shape: Convex, linear
Across -slope shape: Convex, linear
Parent material: Colluvium derived from igneous and metamorphic rock
Typical profile
Ap - 0 to 10 inches: silt
loam
BA - 10 to 15 inches:
loam
Bt1 - 15 to 25 inches:
silt loam
Bt2 - 25 to 38 inches:
silt loam
Bt3 - 38 to 50 inches:
gravelly loam
BC - 50 to 80 inches:
very cobbly sandy loam
Properties and qualities
Slope: 8 to 15 percent
Surface area covered with cobbles, stones or boulders: 0.1 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high
(0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
19

Custom Soil Resource Report
Frequency of ponding: None
Available water supply, 0 to 60 inches: Moderate (about 8.7 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: B
Hydric soil rating: No
Minor Components
Dillsboro
Percent of map unit. 7 percent
Landform: Coves, stream terraces
Landform position (two-dimensional): Footslope, toeslope
Landform position (three-dimensional): Mountainbase, base slope
Down -slope shape: Concave, convex
Across -slope shape: Concave, linear
Hydric soil rating: No
Thunder
Percent of map unit. 6 percent
Landform: Fans, coves, drainageways
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Mountainbase, base slope
Down -slope shape: Linear, concave
Across -slope shape: Concave, linear
Hydric soil rating: No
Cullasaja
Percent of map unit. 4 percent
Landform: Coves, drainageways, fans
Landform position (two-dimensional): Toeslope
Landform position (three-dimensional): Mountainbase, base slope
Down -slope shape: Convex, linear
Across -slope shape: Convex, linear
Hydric soil rating: No
Bandana
Percent of map unit. 3 percent
Landform: Flood -plain steps
Landform position (three-dimensional): Rise
Down -slope shape: Linear
Across -slope shape: Linear
Hydric soil rating: No
Ud—Udorthents, loamy
Map Unit Setting
National map unit symbol: Icth
Elevation: 1,150 to 6,180 feet
20

Custom Soil Resource Report
Mean annual precipitation: 48 to 60 inches
Mean annual air temperature: 46 to 57 degrees F
Frost -free period: 116 to 170 days
Farmland classification: Not prime farmland
Map Unit Composition
Udorthents, loamy, and similar soils: 90 percent
Minor components: 10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Udorthents, Loamy
Setting
Landform position (two-dimensional): Backslope
Landform position (three-dimensional): Side slope
Down -slope shape: Convex, linear
Across -slope shape: Convex
Parent material: Loamy and stony mine spoil or earthy fill derived from
metamorphic rock
Typical profile
C - 0 to 80 inches: sandy clay loam
Properties and qualities
Slope: 2 to 50 percent
Surface area covered with cobbles, stones or boulders: 0.1 percent
Depth to restrictive feature: More than 80 inches
Drainage class: Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water (Ksat): Moderately low to very
high (0.06 to 19.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: Moderate (about 7.2 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 7e
Hydrologic Soil Group: C
Hydric soil rating: No
Minor Components
Urban land
Percent of map unit. 9 percent
Hydric soil rating: No
Rubble land
Percent of map unit. 1 percent
Hydric soil rating: No
21

References
American Association of State Highway and Transportation Officials (AASHTO).
2004. Standard specifications for transportation materials and methods of sampling
and testing. 24th edition.
American Society for Testing and Materials (ASTM). 2005. Standard classification of
soils for engineering purposes. ASTM Standard D2487-00.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of
wetlands and deep -water habitats of the United States. U.S. Fish and Wildlife
Service FWS/OBS-79/31.
Federal Register. July 13, 1994. Changes in hydric soils of the United States.
Federal Register. September 18, 2002. Hydric soils of the United States.
Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric
soils in the United States.
National Research Council. 1995. Wetlands: Characteristics and boundaries.
Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service.
U.S. Department of Agriculture Handbook 18. http://www.nres.usda.gov/wps/portal/
n res/d eta i I/n ati o n a I/s o i Is/?cid = n res 142 p2_0 54262
Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for
making and interpreting soil surveys. 2nd edition. Natural Resources Conservation
Service, U.S. Department of Agriculture Handbook 436. http://
www. nres. usda.gov/wps/portal/nres/detail/national/soils/?cid=nres142p2_053577
Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of
Agriculture, Natural Resources Conservation Service. http://
www. nres. usda.gov/wps/portal/nres/detail/national/soils/?cid=nres142p2_053580
Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and
Delaware Department of Natural Resources and Environmental Control, Wetlands
Section.
United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of
Engineers wetlands delineation manual. Waterways Experiment Station Technical
Report Y-87-1.
United States Department of Agriculture, Natural Resources Conservation Service.
National forestry manual. http://www.nres.usda.gov/wps/portal/nres/detail/soils/
home/?cid=nres142p2_053374
United States Department of Agriculture, Natural Resources Conservation Service.
National range and pasture handbook. http://www.nres.usda.gov/wps/portal/nres/
detail/national/landuse/rangepastu re/?cid=stelprdb1043084
22

Custom Soil Resource Report
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430-VI. http://www.nres.usda.gov/wps/portal/
n res/d eta i I/so i Is/scie ntists/?cid=n res 142 p2_054242
United States Department of Agriculture, Natural Resources Conservation Service.
2006. Land resource regions and major land resource areas of the United States,
the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook
296. http://www.nres.usda.gov/wps/portal/nres/detail/national/soils/?
cid = n res 142 p2_05 3624
United States Department of Agriculture, Soil Conservation Service. 1961. Land
capability classification. U.S. Department of Agriculture Handbook 210. http:H
www.nrcs.usda.gov/lnternet/FSE—DOCUMENTS/nrcsl 42p2_052290. pdf
23

APPENDIX C
NOAA Rainfall Data

3/14/22, 11:47 AM
Precipitation Frequency Data Server
NOAA Atlas 14, Volume 2, Version 3 "b
' Location name: Bakersville, North Carolina, USA*
Latitude: 35.96590, Longitude:-82.11720
Elevation: 2737.18 ft**
' source: ESRI Maps Q0
** source: USGS '
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M. Bonnin, D. Martin, B. Lin, T. Parcybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring, Maryland
PF tabular I PF graphical I Maps & aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches/hour)1
Average recurrence interval (years)
Duration
1
��
2
10
25
�����
50
100 200
500
0
1000
5-min
4.42
5.27
Lkt(6.35-7.67)
6.98
7.99
8.76
9.54
10.3
11.4
12.3
4
( .03-4.85)
(4.81-5.78)
(7.21-8.78)
(7.85-9.65)
(8.47-10.5)
(9.10-11.5)
(9.86-12.8 )
( 10.5-13.8 )
3.52
4.21
4.99
5.59
6.37
6.97
7.58
8.20
9.02
9.66
10-min
(3.22-3.88)
(3.85-4.63)
(4.54-5.48)
(5.08-6.13)
(5.75-7.00)
(6.25-7.68)
(6.73-8.37)
(7.21-9.10)
(7.80-10.1)
(8.24-10.9)
2.94
3.53
4.21
4.71
5.38
5.88
6.39
6.89
7.57
8.08
15-min
(2.68-3.23)
(3.23-3.88)
(3.83-4.62)
(4.28-5.17)
(4.86-5.91)
(5.27-6.48)
(5.68-7.05)
(6.06-7.66)
(6.55-8.46)
(6.89-9.11)
2.01
2.44
2.99
3.41
3.98
4.43
4.89
5.37
6.02
6.54
30-min
(1.84-2.21)
(2.23-2.68)
(2.72-3.28)
(3.10-3.74)
(3.60-4.38)
(3.97-4.88)
(4.35-5.40)
(4.72-5.96)
(5.21-6.73)
(5.58-7.38)
1.25
1.53
1.92
2.22
2.65
3.00
3.37
3.76
4.32
4.78
60-min
(1.15-1.38)
(1.40-1.68)
(1.74-2.10)
(2.02-2.44)
(2.39-2.92)
(2.69-3.31)
(2.99-3.72)
(3.31-4.18)
(3.74-4.83)
(4.07-5.39)
0.720
0.880
1.11
1.31
1.58
1.81
2.06
2.33
2.72
3.06
2-hr
(0.656-0.790)
(0.800-0.966)
(1.01-1.22)
1 (1.18-1.43)
11 (1.42-1.73)
1 (1.61-1.99)
1 (1.82-2.27)
(2.03-2.58)
(2.33-3.04)
(2.58-3.45)
0.521
0.632
0.796
0.932
1.14
1.31
1.49
1.70
2.01
2.28
3-hr
(0.475-0.574)
(0.577-0.697)
(0.725-0.877)
(0.845-1.03)
(1.02-1.25)
1 (1.16-1.44)
1 (1.31-1.66) 11
(1.48-1.90)
1 (1.71-2.26)
1 (1.91-2.58)
0.334
0.402
0.498
0.579
0.700
0.804
0.918
1.05
1.24
1.40
6-hr
(0.307-0.364)
(0.370-0.439)
(0.456-0.544)
(0.528-0.632)
(0.633-0.765)
(0.721-0.881)
(0.813-1.01)
(0.914-1.16)
1 (1.06-1.38)
1 (1.18-1.58)
12-hr
0.19 0 230
0.236-0 278
0.290-0 343
0.332-0 394
0.392-0 468
0.439-0 530
0.488-0 596
0.539-0 669
0.611--0..776
0.6770-0 869
0.135
0.164
0.207
0.242
0.290
0.331
0.373
0.419
0.484
0.538
24-hr
(0.123-0.150)
(0.149-0.182)
(0.188-0.230)
(0.219-0.269)
(0.261-0.324)
(0.295-0.370)
(0.331-0.419)
(0.368-0.472)
(0.419-0.549)
(0.460-0.615)
0.081
0.098
0.123
0.143
0.172
0.196
0.221
0.247
0.286
0.317
2iiay
(0.074-0.089)
(0.090-0.107)
(0.113-0.135)
(0.131-0.158)
(0.155-0.189)
(0.176-0.216)
(0.196-0.245)
(0.218-0.276)
(0.248-0.321)
(0.272-0.360)
0.058
0. 770
0.087
0.101
0. 220
0.136
0.153
0.171
0.196
0.217
3�iay
(0.053-0.063)
(0.064-0.076)
(0.080-0.096)
(0.092-0.111)
(0.109-0.132)
(0.123-0.150)
(0.137-0.169)
(0.151-0.190)
(0.171-0.220)
(0.187-0.246)
0.046
0.056
0.069
0.080
0.095
0.107
0.119
0.133
0.151
0.167
aiiay
(0.043-0.051)
(0.051-0.061)
(0.063-0.076)
(0.073-0.087)
(0.086-0.104)
(0.096-0.118)
(0.107-0.132)
(0.118-0.147)
(0.133-0.169)
(0.145-0.189)
7iiay
0.028-0.034
0.034 0 040
0.041--0 049
0.047--0.057
0.055-0 066
0. 61--0 074
0. 67--0 083
0.073-0 092
0. 82--0..1105
0. 88-0 115
0.025
0.029
0.035
0.040
0.046
0.051
0.056
0.061
0.068
0.074
10-day
(0.023-0.027)
(0.027-0.032)
(0.033-0.039)
(0.037-0.044)
(0.042-0.051)
(0.046-0.056)
(0.051-0.062)
(0.055-0.067)
(0.060-0.076)
(0.065-0.083)
0.017
0.020
0.023
0.026
0.030
0.033
0.036
0.039
0.043
0.046
20-day
(0.015-0.018)
(0.018-0.021)
(0.022-0.025)
(0.024-0.028)
(0.027-0.032)
(0.030-0.035)
(0.033-0.039)
(0.035-0.042)
(0.039-0.047)
(0.041-0.051)
0.014
0.016
0.019
0.021
0.023
0.025
0.027
0.029
0.032
0.033
30-day
(0.013-0.015)
(0.015-0.017)
(0.017-0.020)
(0.019-0.022)
(0.022-0.025)
(0.023-0.027)
(0.025-0.029)
(0.027-0.031)
(0.029-0.034)
(0.030-0.037)
0.011
0.013
0.015
0.017
0.019
0.020
0.021
0.023
0.025
0.026
45-day
(0.011-0.012)
(0.013-0.014)
(0.014-0.016)
(0.016-0.018)
(0.017-0.020)
(0.019-0.021)
(0.020-0.023)
(0.021-0.024)
(0.023-0.026)
(0.024-0.028)
60-day
0.010-0.011
0.011--0 013
0.01 0 014
0.014-0 016
0.015 0 017
0.016 0 018
0.017--0 020
0.018 0 021
0.019 0.022
0.020-0 024
Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for a
given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not
checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values.
Please refer to NOAA Atlas 14 document for more information.
Back to Top
PF graphical
https://hdsc.nws.noaa.gov/hdsctpfds/pfds_printpage.html?lat=35.9659&Ion=-82.1172&data=intensity&units=english&series=pds 1/4

3/14/22, 11:46 AM
Precipitation Frequency Data Server
NOAA Atlas 14, Volume 2, Version 3 "b
' Location name: Bakersville, North Carolina, USA*
Latitude: 35.96590, Longitude:-82.11720
Elevation: 2737.18 ft**
' source: ESRI Maps Q0
** source: USGS '
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M. Bonnin, D. Martin, B. Lin, T. Parcybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring, Maryland
PF tabular I PF graphical I Maps & aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1
Average
recurrence interval (years)
Duration
1
����������
2
5
10
25
50
100
200
500
1000
0.368
0.439
0.519
0.582
0.666
0.730
0.795
0.862
0.950
1.02
5-min
(0.336-0.404)
(0.401-0.482)
(0.473-0.570)
(0.529-0.639)
(0.601-0.732)
(0.654-0.804)
(0.706-0.878)
(0.758-0.957)
(0.822-1.06)
(0.872-1.15)
0.587
0.702
0.832
0.931
1.06
1.16
1.26
1.37
1.50
1.61
10-min
(0.536-0.646)
(0.642-0.771)
(0.757-0.913)
(0.846-1.02)
(0.958-1.17)
1 (1.04-1.28) 11
(1.12-1.40) 11
(1.20-1.52)
(1.30-1.68)
(1.37-1.82)
0.734
0.882
1.05
1.18
1.35
1.47
1.60
1.72
1.89
2.02
15-min
(0.670-0.807)
(0.807-0.969)
(0.957-1.16)
(1.07-1.29)
11 (1.21-1.48)
1 (1.32-1.62) 11
(1.42-1.76) 11
(1.52-1.91)
(1.64-2.12)
(1.72-2.28)
1.01
1.22
1.49
1.71
1.99
2.22
2.45
2.68
3.01
3.27
30-min
(0.919-1.11)
(1.11-1.34)
1 (1.36-1.64) 11
(1.55-1.87)
11 (1.80-2.19)
1 (1.99-2.44)
(2.17-2.70) 11
(2.36-2.98)
(2.61-3.37)
(2.79-3.69)
1.25
1.53
1.92
2.22
2.65
3.00
3.37
3.76
4.32
4.78
60-min
(1.15-1.38) 11
(1.40-1.68)
(1.74-2.10)
(2.02-2.44)
(2.39-2.92)
(2.69-3.31)
(2.99-3.72) 11
(3.31-4.18)
(3.74-4.83)
( 4.07-5.39)
2-hr
1.44
(1 .31-1.58) 11
1.76
(1.60-1.93)
2.23
(2.03-2.44)
2.61
(2.37-2.86)
3.16
(2.84-3.47)
3.62
(3.23-3.98)
4.12
(3.64-4.55)
4.66
(4.07-5.16)
5.45
(4.67-6.09)
6.11
(5.17-6.89)
1.56
1.90
2.39
7 2.80
3.41
3.92
7 4-A8
5.11
F 6.04
6.84
3-hr
(1.43-1.73)
(1.73-2.09)
(2.18-2.63)
(2.54-3.08)
(3.06-3.75)
(3.49-4.34)
(3.95-4.97)
(4.44-5.70)
(5.14-6.79)
(5.74-7.76)
2.00
2.41
2.98
7 3-A7
4.19
4.82
7 5.50
6.26
F 7.40
8.39
6-hr
(1.84-2.18)
(2.21-2.63)
(2.73-3.26)
(3.16-3.78)
(3.79-4.58)
(4.32-5.27)
(4.87-6.05)
(5.47-6.93)
(6.34-8.27)
(7.06-9.45)
12-hr
2 8 2678
2.85 3935
3.49 4013
4.01 4675Q412-5.64)5.29
6338
5. 8---7318
6.49 8906
7. 8 9735
8.07-310.5
24-hr
3.25
3.93
4.97
5.80
6.97
7.94
8.96
10.1
11.6
12.9
(2.96-3.61)
(3.58-4.37)
(4.51-5.52)
(5.25-6.45)
(6.27-7.77)
(7.09-8.87)
1 (7.94-10.1) 11
(8.82-11.3)
(10.1-13.2)
(11.0-14.8)
2iiay
3.90
4.70
5.91
6.89
8.26
9.39
10.6
11.9
13.7
15.2
(3.57-4.27)
(4.31-5.16)
(5.41-6.49)
(6.27-7.56)
(7.46-9.09)
(8.43-10.4)
(9.43-11.7) 11
(10.5-13.2)
( 11.9-15.4)
( 13.0-17.3)
4.17
5.03
6.27
7.27
8.67
9.82
11.0
12.3
14.1
15.6
3�iay
(3.83-4.57)
(4.61-5.51)
(5.74-6.88)
(6.63-7.97)
(7.85-9.53)
(8.83-10.8) 11
(9.84-12.2) 11
(10.9-13.7)
( 12.3-15.8)
( 13.5-17.7)
4.45
5.35
6.64
7.66
9.09
10.2
11.5
12.7
14.5
16.1
aiiay
(4.09-4.87)
(4.92-5.85)
(6.08-7.26)
(7.00-8.38)
(8.25-9.97)
(9.24-11.3) 11
(10.2-12.7) 11
(11.3-14.1)
(12.7-16.3)
(13.9-18.1)
7iiay
4.76 5667
5. 0 6.78
6.94 8 29
7.92 9?49
9.23- 1.2
10.2- 2.5
11 3-13.9
12.3- 5.4
1317--167.6
14.8- 9.3
10-day
5.90
(5.47-6.45)
7.03
(6.51-7.68)
8.45
(7.81-9.25)
9.55
(8.82-10.5)
11.0
(10.1-12.1)
12.2
(11.1-13.4) 11
13.4
(12.1-14.8) 11
14.6
(13.2-16.2)
16.2
(14.5-18.2)
17.6
(15.6-19.9)
7.94
9.39
11.1
12.4
14.2
15.7
17.1
18.6
20.5
22.1
20-day
(7.42-856)
(8.76-10.1)
(10.3-12.0)
(11.6-13.4)
(13.2-15.4)
(14.4-17.0)
(15.7-18.6)
(16.9-20.3)
(18.5-22.6)
(19.8-24.4)
9.81
11.6
13.4
14.8
16.7
18.1
19.5
20.9
22.7
24.1
30-day
(9.21-10.5)
(10.8-12.4)
(12.6-14.4)
(13.9-15.9)
(15.5-17.9)
(16.8-19.5)
(18.0-21.1)
(19.2-22.7)
(20.7-24.8)
(21.8-26.5)
12.4
14.5
16.5
18.0
20.1
21.6
23.1
24.6
26.5
27.9
45-day
(11.7-13.1)
(13.7-15.3)
(15.6-17.5)
(17.0-19.1)
(18.9-21.3)
(20.3-23.0)
(21.6-24.7)
(22.8-26.3)
(24.5-28.5)
(25.6-30.2)
60-day
0-32.4
1410- 5.6 �LCI
8.2 �Ltj
49 0.6
20.11 2.4
22213 4.8
23-6-26.6
25A- 8.4
26 4$ 0.1
28
29 3134.1
Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for
a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are
not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values.
Please refer to NOAA Atlas 14 document for more information.
Back to Top
PF graphical
https://hdsc.nws.noaa.gov/hdsctpfds/pfds_printpage.html?lat=35.9659&Ion=-82.1172&data=depth&units=english&series=pds 1/4

APPENDIX D
Existing and Proposed Drainage Area Maps

0
mor1fH
7 I
/ BYPASS AREA
01 100 (YELLOW) 1.46 AC / / / / / / / I / - rj 1
TEMPORARY DITCH 'A2'
� 1
DRAINAGE AREA: 6.78 AC
100
BYPASS AREA — /%i \ \ / — — — _ ,� ti / } / � to 1 I
(YELLOW) 0.11 AC > ////�/ #1 — ���/ / \ \ I
——...�`�` 0000
TO
TEMPORARY DITCH 'Al'
DRAINAGE AREA: 2.59 AC
_ \ TEMPORARY DITCH 'C'
DRAINAGE AREA: 4.72 AC
TEMPORARY DITCH 'B'
DRAINAGE AREA: 0.45 AC
Civil
Design
Concepts, PA
NCBELS #: C-2184
IDI l l JAI
77�
MITCHELL COUNTY COUNTY MIDDLE SCHOOL
EROSION CONTROL DRAINAGE BULLETIN
SKIMMER 'A' DRAINAGE AUGUST 2022
AREA 9.37 AC

"ex establishedwithintiaditionalry °;_ °u[ o_
o m o "g. a r-� a• seer uFe c°�vdr ; 3 3
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• a Revd Sin9ie while �ma
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EXISTING PROPERTY LINE (TYP)
8 I £�
�jpn irx.a MITCHELL COUNTY COUNTY MIDDLE SCHOOL
1 (m Ids P—n N °49 8"W 1354.71
=Pgw > �' I PRE DEVELOPMENT DRAINAGE BULLETIN
Design
Concepts, PA
NCBELS#: C-2184 AUGUST 2022

o rti o g r established within traditionalry
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> >'
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'° • rw�3 T
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(TOTAL DRAINAGE AREA 7.56 AC.)
=rt.:
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J
EXISTING PROPERTY LINE (TYP)
m
�' �J v \ \ EXISTING 2' CONTOURS
n V
"
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-2780 --- \�I �o
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-
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F x(M ldimPair) ma m< I m
N B°4 k54.7}
Z_ > > I POST DEVELOPMENT DRAINAGE BULLETIN
Design
Concepts, PA
NCBELS#: C-2184 AUGUST 2022

I- Vxthin traditionalty o3 o a - -
established w -
Ud z S p , maintained . ' a ' s^� ,wvN £ E �I
a a c Ni nmi Al - z
—
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own rai°. �.,.-
w
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� - 504°06'51'E 31.62' 'l � 0°*C�'°f�
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0 100, ID
m �3 s .m
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L54,MITCHELL COUNTY COUNTY MIDDLE SCHOOL
z8°4WI.
STRUCTURE DRAINAGE AREA BULLETIN
Design ~
Concepts, PA
NCBELS#: C-2184 SEPTEMBER 2022

APPENDIX E
Skimmer Basin Design Calculations

-0m
MITCHELL COUNTY MIDDLE SCHOOL
C'DCer, p,,, CDC Proj ect No.: 12208
TEMPORARY SEDIMENT BASIN SCHEDULE
BASIN INFORMATION
Trap/Basin ID
A(1)
A(2)
Units
Basin Type
Skimmer
Skimmer
Maximum Drainage Area
10
10
acre
Drainage Area (DA)
2.59
6.78
acre
Disturbed Area
2.59
6.78
acre
Runoff Coefficient (C)
0.6
0.6
Rainfall Intensity (I10)
7.99
7.99
in/hr
Top of Water Length
See HydroCAD
feet
Top of Water Width
See HydroCAD
feet
L/W Ratio
2.0:1
2.0:1
feet
Water Depth
2.00
2.00
feet
Side Slope Ratio
2.00
2.00
X:1
Bottom of Basin Length
See HydroCAD
feet
Bottom of Basin Width
See HydroCAD
feet
SURFACE AREA & VOLUME
Runoff (10 Year Event)
12.42
32.50
cfs
Minimum Volume
4,662
12,204
cu-ft
Volume Provided
8,052
20,619
cu-ft
Minimum Surface Area
4,035
10,564
sq-ft
Surface Area Provided
4,190
10,606
sq-ft
SKIMMER SIZE
Drawdown Time
3
days
Skimmer Size
2.0
inch
Orifice Diameter
2.7
inch
Does the basin have a spillway? Yes
SPILLWAY SIZE
Spillway Dimensions
29xl.5
feet
Water Depth
0.49
feet
Free -Board
1.01
feet
NCDENR E&SC Manual (Ch 6.6)
Weighted Coefficient
at T C
2:1 Min, 6:1 Max
2' min for Skimmer & Basin
= Lt - 2 (Slope x Depth)
= Wt - 2 (Slope x Depth)
=DAxCxI
In NC assume 3 days
Faircloth Skimmer Chart
Faircloth Orifice Factors
Notes:
1. Spillway dimensions are based on Table 6.60a "Design of Spillways" from the NC Erosion & Sediment Control Planning & Design
Manual
2. Rainfall Intensity, I, is obtained from Appendix 8.03.07 from the NC Erosion & Sediment Control Planning & Design Manual
3. Skimmer Design is based off of the Faircloth Skimmer Packet
4. Drawdown time is per NCDENR requirements
Issued 8/24/2022

Skimmer Basin - Storage Rainfall not specified
Prepared by Civil Design Concepts Printed 8/29/2022
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC
Summary for Pond 1 P: Skimmer A (1)
[43] Hint: Has no inflow (Outflow=Zero)
Volume Invert Avail.Storaae Storaae Description
#1
2,722.00'
8,052 cf
Custom Stage Data (Irregular)-isted below (Recalc)
Elevation
Surf.Area
Perim.
Inc.Store Cum.Store
Wet.Area
(feet)
(sq-ft)
(feet)
(cubic -feet) (cubic -feet)
(sq-ft)
2,722.00
3,864
251.9
0 0
3,864
2,724.00
4,190
262.2
8,052 8,052
4,529

Skimmer Basin - Storage Rainfall not specified
Prepared by Civil Design Concepts Printed 8/29/2022
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC
Summary for Pond 2P: Skimmer A (2)
[43] Hint: Has no inflow (Outflow=Zero)
Volume Invert Avail.Storaae Storaae Description
#1
2,722.00'
20,619 cf
Custom Stage Data (Irregular)-isted below (Recalc)
Elevation
Surf.Area
Perim.
Inc.Store Cum.Store
Wet.Area
(feet)
(sq-ft)
(feet)
(cubic -feet) (cubic -feet)
(sq-ft)
2,722.00
10,017
383.2
0 0
10,017
2,724.00
10,605
393.6
20,619 20,619
11,025

APPENDIX F
Flowrate Calculations and Channel Protection

DC-7iqq
ign
COnC."JI PA
FLOWRATE CALCULATIONS
Mitchell Middle School
CDC Proj ect No.: 12208
DITCH CALCULATIONS
DITCH
RUNOFF "C"
10-YEAR INTENSITY (IN/HR)
DRAINAGE
AREA AC
FLOWRATE (CFS)
TEMPORARY DITCH Al
0.25
6.98
2.40
4.19
TEMPORARY DITCH A2
0.25
6.98
5.84
10.19
TEMPORARY DITCH B
0.25
6.98
0.45
0.79
TEMPORARY DITCH C
0.35
6.98
4.72
11.53
PERMANENT DITCH A
0.55
6.98
0.60
2.30
Note: Permanent Ditch'A' has been oversized to accommodate an additional 16-cfs from the
offsite drainage basin to the northwest should open throat structure C3 become up to 50%
clogged. Offsite woodland drainage will result in approximately 32-cfs on a 10 year storm
event.
Issued 9/23/2022

9/23/22, 12:27 PM
NORTH
AMERICAN
GREEN
CHANNEL ANALYSIS
> > > Permanent Ditch A
Name
Permanent Ditch A
Discharge
18.3
Channel Slope
0.08
Channel Bottom Width
2
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
Excellent > 95%
Soil Type
Clay Loam (CL)
C350
x6Id/IDNWAEII
North American Green
5401 St. Wendel -Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
> Fax [phone]
www.nagreen.com
ECMDS v7.0
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
C350
Straight
18.3 cfs
7.83 ft/s
0.61 ft
0.029
3.2 Ibs/ft2
3.04 Ibs/ft2
1.05
STABLE E
Unvegetated
Underlying
Straight
18.3 cfs
7.83 ft/s
0.61 ft
0.029
3.49 Ibs/ft2
1.99 Ibs/ft2
1.75
STABLE E
Substrate
C350 Reinforced
Straight
18.3 cfs
8.88 ft/s
0.56 ft
0.024
12 Ibs/ft2
2.79 Ibs/ft2
4.3
STABLE E
Vegetation
Underlying
Straight
18.3 cfs
8.88 ft/s
0.56 ft
0.024
3.2 Ibs/ft2
1.86 Ibs/ft2
1.72
STABLE E
Substrate
https://ecmds.com/project/151501/channel-analysis/231746/show 1 /1

8/5/22, 10:43 AM
NORTH
AMERICAN
GREEN
CHANNEL ANALYSIS
> > > TEMPORARY DITCH Al
Name
TEMPORARY DITCH Al
Discharge
4.19
Channel Slope
0.061
Channel Bottom Width
1
Left Side Slope
2
Right Side Slope
2
Low Flow Liner
Retardence Class
C 6-12 in
Vegetation Type
Mix (Sod and Bunch)
Vegetation Density
Very Good 80-95%
Soil Type
Clay Loam (CL)
S150BN
ECMDS 7.0
North American Green
5401 St. Wendel -Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
> Fax [phone]
www.nagreen.com
ECMDS v7.0
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
S150BN Straight 4.19 cfs 4.8 ft/s 0.46 ft 0.033 1.9 Ibs/ft2 1.73 Ibs/ft2 1.1 STABLE D
Unvegetated
Underlying Straight 4.19 cfs 4.8 ft/s 0.46 ft 0.033 2.07 Ibs/ft2 1.09 Ibs/ft2 1.9 STABLE D
Substrate
Unreinforced Vegetation
Phase Reach Discharge Velocity
Normal Mannings N Permissible Calculated Safety Remarks Staple
Depth Shear Stress Shear Stress Factor Pattern
lnreinforced Straight 4.19 cfs 3.95 ft/s 0.52 ft 0.043 4 Ibs/ft2 1.98 Ibs/ft2 2.02 STABLE
Vegetation
Underlying Straight 4.19 cfs 3.95 ft/s 0.52 ft 0.043 4 Ibs/ft2 1.21 Ibs/ft2 3.3 STABLE
Substrate
https://ecmds.com/project/151501/channel-analysis/220424/show 1 /1

8/5/22, 10:46 AM
NORTH
AMERICAN
GREEN
CHANNEL ANALYSIS
> > > TEMPORARY DITCH A2
Name
TEMPORARY DITCH A2
Discharge
10.19
Channel Slope
0.026
Channel Bottom Width
2
Left Side Slope
2
Right Side Slope
2
Low Flow Liner
Retardence Class
D 2-6 in
Vegetation Type
Mix (Sod and Bunch)
Vegetation Density
Excellent > 95%
Soil Type
Clay Loam (CL)
Unreinforced Vegetation
ECMDS 7.0
North American Green
5401 St. Wendel -Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
> Fax [phone]
www.nagreen.com
ECMDS v7.0
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Mannings N Remarks
Depth Shear Stress Shear Stress Factor Pattern
Unreinforced Straight 10.19 cfs 4.16 ft/s 0.71 ft 0.035 4 Ibs/ft2 1.16 Ibs/ft2 3.46 STABLE
Vegetation
Underlying Straight 10.19 cfs 4.16 ft/s 0.71 ft 0.035 3.17 Ibs/ft2 0.76 Ibs/ft2 4.14 STABLE
Substrate
S75BN
Phase Reach Discharge Velocity
Normal Mannings N Permissible Calculated Safety Remarks Staple
Depth Shear Stress Shear Stress Factor Pattern
S75BN Straight 10.19 cfs 4.5 ft/s 0.67 ft 0.031 1.6 Ibs/ft2 1.09 Ibs/ft2 1.46 STABLE D
Unvegetated
Underlying Straight 10.19 cfs 4.5 ft/s 0.67 ft 0.031 1.74 Ibs/ft2 0.73 Ibs/ft2 2.39 STABLE D
Substrate
https://ecmds.com/project/151501/channel-analysis/220408/show 1 /1

8/25/22, 6:00 PM
NORTH
AMERICAN
GREEN
CHANNEL ANALYSIS
> > > Temporary Ditch B
Name
Temporary Ditch B
Discharge
0.79
Channel Slope
0.06
Channel Bottom Width
1
Left Side Slope
2
Right Side Slope
2
Low Flow Liner
Retardence Class
E <2 in
Vegetation Type
None
Vegetation Density
Poor < 50%
Soil Type
Silt Loam (SM)
S150BN
ECMDS 7.0
North American Green
5401 St. Wendel -Cynthia na Rd.
Poseyville, Indiana 47633
Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v7.0
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Depth Mannings N Shear Stress Shear Stress Factor Remarks Pattern
S150BN Straight 0.79 cfs 2.64 ft/s 0.21 ft 0.039 1.9 Ibs/ft2 0.78 Ibs/ft2 2.44 STABLE D
Unvegetated
Underlying Straight 0.79 cfs 2.64 ft/s 0.21 ft 0.039 1.39 Ibs/ft2 0.57 Ibs/ft2 2.44 STABLE D
Substrate
hftps://ecmds.com/project/153137/channel-analysis/230307/show 1 /1

8/25/22, 6:09 PM
NORTH
AMERICAN
GREEN
CHANNEL ANALYSIS
> > > Temporary Ditch C
Name
Temporary Ditch C
Discharge
11.53
Channel Slope
0.05
Channel Bottom Width
2
Left Side Slope
2
Right Side Slope
2
Low Flow Liner
Retardence Class
D 2-6 in
Vegetation Type
Mix (Sod and Bunch)
Vegetation Density
Fair 50-64%
Soil Type
Clay Loam (CL)
SC150BN
ECMDS 7.0
North American Green
5401 St. Wendel -Cynthia na Rd.
Poseyville, Indiana 47633
Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v7.0
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Depth Mannings N Shear Stress Shear Stress Factor Remarks Pattern
SC150BN Straight 11.53 cfs 5.83 ft/s 0.61 ft 0.032 2 Ibs/ft2 1.91 Ibs/ft2 1.05 STABLE D
Unvegetated
Underlying Straight 11.53 cfs 5.83 ft/s 0.61 ft 0.032 2.18 Ibs/ft2 1.3 Ibs/ft2 1.68 STABLE D
Substrate
Unreinforced Vegetation
Normal Permissible Calculated Safety Staple
Phase Reach Discharge Velocity Depth Mannings N Shear Stress Shear Stress Factor Remarks Pattern
Inreinforced Straight 11.53 cfs 6.29 ft/s 0.58 ft 0.029 4 Ibs/ft2 1.81 Ibs/ft2 2.21 STABLE
Vegetation
Underlying Straight 11.53 cfs 6.29 ft/s 0.58 ft 0.029 1.28 Ibs/ft2 1.25 Ibs/ft2 1.03 STABLE
Substrate
hftps://ecmds.com/project/153137/channel-analysis/230310/show 1 /1

Channel Report
Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc.
TD Al Temporary Pipe
Circular
Diameter (ft) = 1.50
Invert Elev (ft) = 100.00
Slope (%) = 1.00
N-Value = 0.010
Calculations
Compute by: Known Q
Known Q (cfs) = 1.50
Elev (ft)
102.00
101.50
101.00
100.50
100.00
99.50
Highlighted
Depth (ft)
Q (cfs)
Area (sqft)
Velocity (ft/s)
Wetted Perim (ft)
Crit Depth, Yc (ft)
Top Width (ft)
EGL (ft)
Section
Thursday, Aug 25 2022
= 0.34
= 1.500
= 0.30
= 4.95
= 1.49
= 0.46
= 1.26
= 0.72
0 1 2 3
Reach (ft)

Channel Report
Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc.
TD B Temporary Pipe
Circular
Diameter (ft) = 1.50
Invert Elev (ft) = 100.00
Slope (%) = 1.00
N-Value = 0.010
Calculations
Compute by: Known Q
Known Q (cfs) = 0.79
Elev (ft)
102.00
101.50
101.00
100.50
100.00
99.50
Highlighted
Depth (ft)
Q (cfs)
Area (sqft)
Velocity (ft/s)
Wetted Perim (ft)
Crit Depth, Yc (ft)
Top Width (ft)
EGL (ft)
Section
Thursday, Aug 25 2022
= 0.25
= 0.790
= 0.20
= 4.03
= 1.27
= 0.33
= 1.12
= 0.50
0 1 2 3
Reach (ft)

APPENDIX G
Rip -rap Apron Calculations

Appendices
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STRUCTURE: Skimmer A LENGTH: 24.0 ft
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PIPE DIA. (D) 24 in d50: 0.9 ft
DEPTH: 1.5 ft
Rev.12/93 8.06.3

Appendices
30
l�]r
Outlet W = Do + La
pipe
diameter (Do)
La —+t
T ilwater < 0 . 5 D o
7
APRON DEPTH IS 1.5 TIMES THE STONE
DIAMETER (18" MINIMUM DEPTH) Pp
20
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Figure 8.06a Design of outlet protection protection from a round pipe flowing full, minimum tailwater condition (Tw < 0.5 diameter).
STRUCTURE: co LENGTH: 16 ft
DISCHARGE: 32.74 cfs WIDTH: 18.5ft
PIPE DIA. (D) 30 in d50: 0.5 ft
DEPTH: 1.5 ft
Rev.12/93 8.06.3

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STRUCTURE: Al LENGTH: 8.0 ft
DISCHARGE: 4.19 cfs WIDTH: 9.0 ft
PIPE DIA. (D) 12 in d50: 0.5 ft
DEPTH: 1.5 ft
Rev. 12/93 8.06.3

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Curves may not be extrapolated.
Figure 8.06a Design of outlet protection protection from a round pipe flowing full, minimum tailwater condition (Tw < 0.5 diameter).
STRUCTURE: A2 LENGTH: 13.0 ft
DISCHARGE: 10.19 cfs WIDTH: 15.0 ft
PIPE DIA. (D) 24 in d50: 0.5 ft
DEPTH: 1.5 ft
Rev.12/93 8.06.3

Appendices
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Curves may not be extrapolated.
Figure 8.06a Design of outlet protection protection from a round pipe flowing full, minimum tailwater condition (Tw < 0.5 diameter).
STRUCTURE: AO LENGTH:
DISCHARGE: 65.74 cfs WIDTH:
PIPE DIA. (D) 36 in d50:
DEPTH:
23.0 ft
26.0 ft
0.6 ft
1.5 ft
Rev.12/93 8.06.3

APPENDIX H
StreamStats Report

8/9/22, 9:38 AM
StreamStats
StreamStats Report - Confluence
Region ID: NC
Workspace ID: NC20220809133654353000
Clicked Point (Latitude, Longitude): 35.96682,-82.11641
Time: 2022-08-09 09:37:15 -0400
�-
l 1ti W { IIjI
a
Basin Characteristics
Parameter
O Collapse All
Code Parameter Description Value Unit
DRNAREA Area that drains to a point on a stream 0.31 square
miles
LC11IMP Average percentage of impervious area determined from 3.9 percent
NLCD 2011 impervious dataset
Urban Peak -Flow Statistics
hftps://streamstats.usgs.gov/ss/
1/3

8/9/22, 9:38 AM StreamStats
Urban Peak -Flow Statistics Parameters [Region 2 Urban Blue Ridge FSOO7-00]
Parameter
Code
DRNAREA
LC11IMP
Parameter Name
Drainage Area
Min Max
Value Units Limit Limit
0.31 square
miles
Percent_Impervious_NLCD2011 3.9 percent
0.04 41
2 54.6
Urban Peak -Flow Statistics Flow Report [Region 2 Urban Blue Ridge FSOO7-00]
PII: Prediction Interval -Lower, Plu: Prediction Interval -Upper, ASEp: Average Standard
Error of Prediction, SE: Standard Error (other -- see report)
Statistic Value Unit SE
Urban 50-percent AEP flood
35.6
ft"3/s
40.4
Urban 20-Percent AEP flood
77.4
ft"3/s
38.5
Urban 10-percent AEP flood
114
ft"3/s
38.3
Urban 4-percent AEP flood
202
ft"3/s
38.7
Urban 2-percent AEP flood
251
ft"3/s
37.8
Urban 1-percent AEP flood
304
ft"3/s
37.8
Urban Peak -Flow Statistics Citations
Mason, Robert R., Jr.; Fuste, Luis A.; King, Jeffrey N.; Thomas, Wilbert 0., Jr.,2002,
The National Flood -Frequency Program -- Methods for Estimating Flood Magnitude and
Frequency in Rural and Urban Areas in North Carolina, 2001: U.S. Geological Survey
Fact Sheet 007-00, 4 p. (http://pubs.er.usgs.gov/publication/fs00700)
USGS Data Disclaimer: Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality
standards relative to the purpose for which the data were collected. Although these data and associated metadata have
been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty
expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems,
nor shall the act of distribution constitute any such warranty.
USGS Software Disclaimer: This software has been approved for release by the U.S. Geological Survey (USGS). Although the
software has been subjected to rigorous review, the USGS reserves the right to update the software as needed pursuant to
further analysis and review. No warranty, expressed or implied, is made by the USGS or the U.S. Government as to the
functionality of the software and related material nor shall the fact of release constitute any such warranty. Furthermore,
the software is released on condition that neither the USGS nor the U.S. Government shall be held liable for any damages
resulting from its authorized or unauthorized use.
hftps://streamstats.usgs.gov/ss/ 2/3

8/9/22, 9:38 AM
StreamStats
USGS Product Names Disclaimer: Any use of trade, firm, or product names is for descriptive purposes only and does not
imply endorsement by the U.S. Government.
Application Version: 4.10.1
StreamStats Services Version: 1.2.22
NSS Services Version: 2.2.1
hftps://streamstats.usgs.gov/ss/ 3/3

8/9/22, 9:41 AM
StreamStats
StreamStats Report - Existing 48" Culvert
Region ID: NC
Workspace ID: NC20220809133949252000
Clicked Point (Latitude, Longitude): 35.96759,-82.11656
Time: 2022-08-09 09:40:09 -0400
Basin Characteristics
Parameter
Code Parameter Description
DRNAREA Area that drains to a point on a stream
LC11IMP Average percentage of impervious area determined from
NLCD 2011 impervious dataset
MW
O Collapse All
Value Unit
0.0997 square
miles
1.3 percent
Urban Peak -Flow Statistics
hftps://streamstats.usgs.gov/ss/ 1 /3

8/9/22, 9:41 AM
StreamStats
Urban Peak -Flow Statistics Parameters [Region 2 Urban Blue Ridge FS007-00]
Parameter Min Max
Code Parameter Name Value Units Limit Limit
DRNAREA Drainage Area 0.0997 square 0.04 41
miles
LC11IMP Percent_Impervious_NLCD2011 1.3 percent 2 54.6
Urban Peak -Flow Statistics Disclaimers [Region 2 Urban Blue Ridge FS007-00]
One or more of the parameters is outside the suggested range. Estimates were extrapolated with
unknown errors.
Urban Peak -Flow Statistics Flow Report [Region 2 Urban Blue Ridge FS007-00]
Statistic
Value
Unit
Urban 50-percent AEP flood
7.26
ft"3/s
Urban 20-Percent AEP flood
19.1
ft"3/s
Urban 10-percent AEP flood
30.8
ft"3/s
Urban 4-percent AEP flood
62.5
ft"3/s
Urban 2-percent AEP flood
82
ft"3/s
Urban 1-percent AEP flood
105
ft"3/s
Urban Peak -Flow Statistics Citations
Mason, Robert R., Jr.; Fuste, Luis A.; King, Jeffrey N.; Thomas, Wilbert 0., Jr.,2002,
The National Flood -Frequency Program -- Methods for Estimating Flood Magnitude and
Frequency in Rural and Urban Areas in North Carolina, 2001: U.S. Geological Survey
Fact Sheet 007-00, 4 p. (http://pubs.er.usgs.gov/publication/fs00700)
USGS Data Disclaimer: Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality
standards relative to the purpose for which the data were collected. Although these data and associated metadata have
been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty
expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems,
nor shall the act of distribution constitute any such warranty.
USGS Software Disclaimer: This software has been approved for release by the U.S. Geological Survey (USGS). Although the
software has been subjected to rigorous review, the USGS reserves the right to update the software as needed pursuant to
further analysis and review. No warranty, expressed or implied, is made by the USGS or the U.S. Government as to the
hftps://streamstats.usgs.gov/ss/ 2/3

8/9/22, 9:41 AM
StreamStats
functionality of the software and related material nor shall the fact of release constitute any such warranty. Furthermore,
the software is released on condition that neither the USGS nor the U.S. Government shall be held liable for any damages
resulting from its authorized or unauthorized use.
USGS Product Names Disclaimer: Any use of trade, firm, or product names is for descriptive purposes only and does not
imply endorsement by the U.S. Government.
Application Version: 4.10.1
StreamStats Services Version: 1.2.22
NSS Services Version: 2.2.1
hftps://streamstats.usgs.gov/ss/ 3/3

APPENDIX I
Storm Drainage Calculations

C CD
0CQ
Design
Concepts, PA
STORM DRAIN CALCULATIONS
(25 YEAR EVENT)
Mitchell County Middle School
CDC Project No.: 12208
PIPE
STRUCTURE
DRAINAGE
W
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\
(FT)
(FT)
(IN)
(FT)
(%)
"N"
(FT)
(FT)
(AC)
(MIN)
"C"
(IN/HR)
(CFS)
(CFS)
(FT/SEC)
(CFS)
(CFS)
Al -AO
2727.20
2725.87
30
26.085
5.10
0.012
Al
2732.16
4.27
0.00
0.0
0.00
0.00
0.00
39.52
19.21
100.32
99.50
A2-Al
2734.20
2727.70
24
72.215
9.00
0.012
A2
2747.91
2.50
0.11
5.0
0.95
7.98
0.83
16.16
5.15
73.51
72.90
A3-A2
2734.60
2734.27
24
66.499
0.50
0.012
A3
2750.02
2.72
0.00
0.0
0.00
0.00
0.00
15.33
4.88
17.26
17.18
A4-A3
2735.10
2734.68
24
83.822
0.50
0.012
A4
2748.90
2.80
0.15
5.0
0.95
7.98
1.14
14.39
4.58
17.35
17.18
A5-A4
2735.30
2735.22
24
19.801
0.40
0.012
A5
2748.22
3.06
0.03
5.0
0.95
7.98
0.23
13.26
4.22
15.58
15.37
A6-A5
2735.80
2735.36
24
87.514
0.50
0.012
A6
2748.98
3.32
0.04
5.0
0.95
7.98
0.30
13.03
4.15
17.37
17.18
El-A3
2738.41
2736.55
15
18.519
10.04
0.012
E1
2749.41
0.94
0.17
5.0
0.95
7.98
1.29
2.43
1.98
22.17
21.99
E2-El
2746.58
2738.50
15
65.506
12.33
0.012
E2
2750.99
0.61
0.13
5.0
0.95
7.98
0.99
1.14
1.28
24.57
24.37
E3-E2
2747.75
2746.70
15
26.263
4.00
0.012
E3
2751.63
0.21
0.02
5.0
1.00
7.98
0.16
0.16
0.36
13.99
13.88
A7-A6
2736.50
2735.92
24
116.596
0.50
0.012
A7
2748.56
2.99
0.01
5.0
0.95
7.98
0.08
10.29
3.28
17.28
17.18
A8-A7
2737.10
2736.60
24
99.978
0.50
0.012
A8
2746.48
2.81
0.16
5.0
0.90
7.98
1.15
10.22
3.25
17.33
17.18
A9-A8
2737.30
2737.22
24
18.940
0.42
0.012
A9
2747.55
2.87
0.31
5.0
0.90
7.98
2.23
9.07
2.89
15.93
15.75
A10-A9
2738.01
2737.40
24
121.672
0.50
0.012
A10
2748.23
2.27
0.00
0.0
0.00
0.00
0.00
5.78
1.84
17.35
17.18
B1-A10
2744.60
2738.75
15
122.205
4.79
0.012
B1
2751.28
1.61
0.40
0.0
0.50
0.00
0.00
5.16
4.20
15.31
15.19
132-131
2746.40
2744.65
15
89.585
1.95
0.012
B2
2750.42
1.22
0.39
5.0
0.95
7.98
2.96
3.56
2.90
9.78
9.69
133-132
2746.88
2746.50
15
22.596
1.68
0.012
B3
2750.65
0.43
0.08
5.0
0.95
7.98
0.61
0.61
0.52
9.07
8.99
F1-Al
2732.90
2727.70
24
184.072
2.82
0.012
F1
2739.94
3.54
0.05
5.0
0.95
7.98
0.38
23.36
7.44
41.18
40.81
F2-F1
2733.50
2732.96
24
22.380
2.41
0.012
F2
2739.61
4.24
0.04
5.0
0.95
7.98
0.30
21.84
6.95
38.06
37.73
H1-F2
2742.91
2734.15
18
75.380
11.62
0.012
H1
2749.04
1.60
0.44
5.0
0.65
7.98
2.28
6.37
3.61
38.78
38.46
H2-H1
2747.77
2743.00
18
168.148
2.84
0.012
H2
2751.84
1.19
0.54
5.0
0.95
7.98
4.09
4.09
2.32
19.16
19.02
F3-F2
2734.39
2733.65
24
32.459
2.28
0.012
F3
2739.37
3.70
0.29
5.0
0.30
7.98
0.69
15.16
4.83
37.00
36.69
F4-F3
2738.50
2734.50
24
126.702
3.16
0.012
F4
2746.08
2.30
0.26
5.0
0.30
7.98
0.62
14.47
4.61
43.54
43.20
F5-F4
2739.90
2738.59
24
130.639
1.00
0.012
F5
2747.80
2.22
0.14
5.0
0.95
7.98
1.06
13.85
4.41
24.53
24.30
F6-F5
2740.74
2740.05
24
69.339
1.00
0.012
F6
2745.91
1.88
0.57
5.0
0.95
7.98
4.32
12.79
4.07
24.44
24.30
F7-F6
2742.35
2741.24
18
110.900
1.00
0.012
F7
2746.01
1.83
0.70
5.0
0.95
7.98
5.31
7.63
4.48
11.38
11.28
F8-F7
2742.98
2742.60
15
42.232
0.90
0.012
F8
2749.21
1.30
0.97
5.0
0.30
7.98
2.32
2.32
1.89
6.63
6.58
G1-F5
2745.67
2741.49
15
48.398
8.64
0.012
G1
2749.67
0.51
0.35
5.0
0.30
7.98
0.84
0.84
0.72
20.56
20.40
All-A10
2738.85
2738.51
18
68.654
0.50
0.012
All
2744.47
1.43
0.11
5.0
0.45
7.98
0.39
0.62
0.35
8.01
7.98
Al2-All
2740.41
2739.10
15
23.012
5.69
0.012
Al2
2744.46
0.26
0.03
5.0
0.95
7.98
0.23
0.23
0.19
16.69
16.55
D1-A9
2745.02
2738.05
15
75.180
9.27
0.012
D1
2750.40
0.59
0.14
5.0
0.95
7.98
1.06
1.06
0.86
21.30
21.13
A3X-A3
2742.90
2735.35
15
68.628
11.00
0.012
A3X
2750.86
0.55
0.13
5.0
0.90
7.98
0.93
0.93
0.76
23.20
23.01
11-F1
2734.37
2733.71
15
65.535
1.01
0.012
11
2737.75
2.10
0.15
5.0
0.95
7.98
1.14
1.14
0.93
7.02
6.97
Cl-CO
2735.10
2733.90
30
100.365
1.20
0.012
C1
2740.45
4.67
0.00
0.0
0.00
0.00
0.00
42.81
11.17
48.59
48.27
C2-Cl
2738.21
2735.20
30
123.975
2.43
0.012
C2
2746.34
4.33
0.00
0.0
0.00
0.00
0.00
42.81
8.72
69.23
68.68
C3-C2
2744.55
2738.30
30
207.433
3.01
0.012
C3
2749.48
4.67
38.40
15.0
0.20
5.57
42.81
42.81
8.72
77.12
76.44
Y1-Y0
2724.59
2724.38
18
28.381
0.74
0.012
Y1
2726.80
0.33
0.20
5.0
0.25
7.98
0.40
0.40
2.71
9.79
9.71
J1-J0
2718.50
2718.20
42
58.772
0.51
0.012
11
2726.80
4.48
0.79
5.0
0.25
7.98
67.32
67.32
9.11
77.88
77.18
Issued 8/29/2022

Stream Culvert Rainfall not specified
Prepared by Civil Design Concepts Printed 8/30/2022
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC
Summary for Reach 1 R: Culvert Z1
[52] Hint: Inlet/Outlet conditions not evaluated
[55] Hint: Peak inflow is 138% of Manning's capacity
[76] Warning: Detained 83.871 of (Pond w/culvert advised)
Inflow = 242.00 cfs @ 5.00 hrs, Volume= 301.000 af, Incl. 242.00 cfs Base Flow
Outflow = 174.90 cfs @ 5.10 hrs, Volume= 216.804 af, Atten= 28%, Lag= 6.0 min
Routing by Stor-Ind+Trans method, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
Max. Velocity= 13.18 fps, Min. Travel Time= 0.1 min
Avg. Velocity = 13.18 fps, Avg. Travel Time= 0.1 min
Peak Storage= 690 cf @ 5.05 hrs
Average Depth at Peak Storage= 4.50' above invert (3.50' above fill)
Bank -Full Depth= 4.50' above invert (3.50' above fill) Flow Area= 13.3 sf, Capacity= 174.90 cfs
54.0" Round Pipe w/ 12.0" inside fill
n= 0.012
Length= 52.0' Slope= 0.0115 T (101 Elevation Intervals)
Inlet Invert= 2,731.10', Outlet Invert= 2,730.50'
0

APPENDIX J
Wet Pond Forebay and Permanent Pool Volume Calculations

Wet Pond 'A' Forebay
Subcat Reach on Link

MITCHELL COUNTY MIDDLE SCHOOL
12208 Stormwater Analysis Type 11 24-hr 50-yr Rainfall=7.94"
Prepared by Civil Design Concepts Printed 8/16/2022
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 2
Summary for Pond 3PF: Wet Pond 'A' Forebay
Volume
Invert Avail.Storage
Storage
Description
#1
2,721.00'
6,404 cf
Custom
Stage Data (Irregular)-isted below (Recalc)
Elevation
Surf.Area
Perim.
Voids
Inc.Store
Cum.Store Wet.Area
(feet)
(sq-ft)
(feet)
(%)
(cubic -feet)
(cubic -feet)
(sq-ft)
2,721.00
285
80.1
0.0
0
0
285
2,721.01
285
80.1
100.0
3
3
286
2,722.00
1,153
153.7
100.0
664
667
1,660
2,725.00
2,791
210.3
100.0
5,738
6,404
3,388

3PP
Wet Pond 'A' Permanent
Pool
Subcat Reach on Link

MITCHELL COUNTY MIDDLE SCHOOL
12208 Stormwater Analysis Type 11 24-hr 50-yr Rainfall=7.94"
Prepared by Civil Design Concepts Printed 8/16/2022
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 2
Summary for Pond 3PP: Wet Pond 'A' Permanent Pool
Volume
Invert Avail.Storage
Storage
Description
#1
2,720.00'
32,541 cf
Custom
Stage Data (Irregular)-isted below (Recalc)
Elevation
Surf.Area
Perim.
Voids
Inc.Store
Cum.Store Wet.Area
(feet)
(sq-ft)
(feet)
(%)
(cubic -feet)
(cubic -feet)
(sq-ft)
2,720.00
4,381
254.7
0.0
0
0
4,381
2,720.01
4,381
254.7
100.0
44
44
4,384
2,725.00
8,909
349.0
100.0
32,497
32,541
9,158

APPENDIX K
24-Hour WQV Drawdown
HydroCAD Output Report

Mitchell County Middle School
12208 Stormwater Analysis Type/1 24-hr 1-in. Rainfall=1.00"
Prepared by Civil Design Concepts Printed 8/9/2022
HydroCAD® 10.20-2f s/n 04679 © 2022 HydroCAD Software Solutions LLC Page 1
Hydrograph for Pond 3P: Proposed Wet Pond 'A'
Time
Inflow
Storage
Elevation
Primary
(hours)
(cfs)
(cubic -feet)
(feet)
(cfs)
0.00
0.00
15,546
2,726.10
0.15
0.16
0.00
15,463
2,726.09
0.15
0.32
0.00
15,379
2,726.09
0.14
0.48
0.00
15,296
2,726.08
0.14
0.64
0.00
15,212
2,726.08
0.14
0.80
0.00
15,129
2,726.07
0.14
0.96
0.00
15,047
2,726.07
0.14
1.12
0.00
14,964
2,726.06
0.14
1.28
0.00
14,882
2,726.06
0.14
1.44
0.00
14,799
2,726.05
0.14
1.60
0.00
14,718
2,726.05
0.14
1.76
0.00
14,636
2,726.04
0.14
1.92
0.00
14,554
2,726.04
0.14
2.08
0.00
14,473
2,726.03
0.14
2.24
0.00
14,392
2,726.02
0.14
2.40
0.00
14,311
2,726.02
0.14
2.56
0.00
14,230
2,726.01
0.14
2.72
0.00
14,150
2,726.01
0.14
2.88
0.00
14,070
2,726.00
0.14
3.04
0.00
13,989
2,726.00
0.14
3.20
0.00
13,910
2,725.99
0.14
3.36
0.00
13,830
2,725.99
0.14
3.52
0.00
13,751
2,725.98
0.14
3.68
0.00
13,671
2,725.98
0.14
3.84
0.00
13,592
2,725.97
0.14
4.00
0.00
13,513
2,725.97
0.14
4.16
0.00
13,435
2,725.96
0.14
4.32
0.00
13,357
2,725.96
0.14
4.48
0.00
13,278
2,725.95
0.14
4.64
0.00
13,200
2,725.95
0.14
4.80
0.00
13,123
2,725.94
0.13
4.96
0.00
13,045
2,725.94
0.13
5.12
0.00
12,968
2,725.93
0.13
5.28
0.00
12,891
2,725.93
0.13
5.44
0.00
12,814
2,725.92
0.13
5.60
0.00
12,737
2,725.92
0.13
5.76
0.00
12,661
2,725.91
0.13
5.92
0.00
12,584
2,725.91
0.13
6.08
0.00
12,508
2,725.90
0.13
6.24
0.00
12,433
2,725.90
0.13
6.40
0.00
12,357
2,725.89
0.13
6.56
0.00
12,282
2,725.89
0.13
6.72
0.00
12,206
2,725.88
0.13
6.88
0.00
12,131
2,725.88
0.13
7.04
0.00
12,057
2,725.87
0.13
7.20
0.00
11,982
2,725.87
0.13
7.36
0.00
11,908
2,725.86
0.13
7.52
0.00
11,834
2,725.86
0.13
7.68
0.00
11,760
2,725.85
0.13
7.84
0.00
11,686
2,725.85
0.13
8.00
0.00
11,613
2,725.84
0.13

Mitchell County Middle School
12208 Stormwater Analysis Type // 24-hr 1-in. Rainfall=1.00"
Prepared by Civil Design Concepts Printed 8/9/2022
HydroCAD® 10.20-2f s/n 04679 © 2022 HydroCAD Software Solutions LLC Page 2
Hydrograph for Pond 3P: Proposed Wet Pond 'A' (continued)
Time
Inflow
Storage
Elevation
Primary
(hours)
(cfs)
(cubic -feet)
(feet)
(cfs)
8.16
0.00
11,539
2,725.84
0.13
8.32
0.00
11,466
2,725.83
0.13
8.48
0.00
11,394
2,725.83
0.13
8.64
0.00
11,321
2,725.82
0.13
8.80
0.00
11,249
2,725.82
0.13
8.96
0.00
11,176
2,725.81
0.13
9.12
0.00
11,105
2,725.81
0.12
9.28
0.00
11,033
2,725.80
0.12
9.44
0.00
10,961
2,725.80
0.12
9.60
0.00
10,890
2,725.79
0.12
9.76
0.00
10,819
2,725.79
0.12
9.92
0.00
10,748
2,725.78
0.12
10.08
0.00
10,677
2,725.78
0.12
10.24
0.00
10,607
2,725.77
0.12
10.40
0.00
10,537
2,725.77
0.12
10.56
0.00
10,467
2,725.76
0.12
10.72
0.00
10,397
2,725.76
0.12
10.88
0.00
10,328
2,725.75
0.12
11.04
0.00
10,258
2,725.75
0.12
11.20
0.00
10,189
2,725.74
0.12
11.36
0.00
10,120
2,725.74
0.12
11.52
0.00
10,052
2,725.73
0.12
11.68
0.00
9,983
2,725.73
0.12
11.84
0.00
9,915
2,725.72
0.12
12.00
0.00
9,847
2,725.72
0.12
12.16
0.00
9,779
2,725.72
0.12
12.32
0.00
9,712
2,725.71
0.12
12.48
0.00
9,644
2,725.71
0.12
12.64
0.00
9,577
2,725.70
0.12
12.80
0.00
9,510
2,725.70
0.12
12.96
0.00
9,444
2,725.69
0.12
13.12
0.00
9,377
2,725.69
0.12
13.28
0.00
9,311
2,725.68
0.11
13.44
0.00
9,245
2,725.68
0.11
13.60
0.00
9,179
2,725.67
0.11
13.76
0.00
9,114
2,725.67
0.11
13.92
0.00
9,048
2,725.66
0.11
14.08
0.00
8,983
2,725.66
0.11
14.24
0.00
8,918
2,725.66
0.11
14.40
0.00
8,854
2,725.65
0.11
14.56
0.00
8,789
2,725.65
0.11
14.72
0.00
8,725
2,725.64
0.11
14.88
0.00
8,661
2,725.64
0.11
15.04
0.00
8,597
2,725.63
0.11
15.20
0.00
8,534
2,725.63
0.11
15.36
0.00
8,470
2,725.62
0.11
15.52
0.00
8,407
2,725.62
0.11
15.68
0.00
8,345
2,725.61
0.11
15.84
0.00
8,282
2,725.61
0.11
16.00
0.00
8,219
2,725.61
0.11
16.16
0.00
8,157
2,725.60
0.11

Mitchell County Middle School
12208 Stormwater Analysis Type // 24-hr 1-in. Rainfall=1.00"
Prepared by Civil Design Concepts Printed 8/9/2022
HydroCAD® 10.20-2f s/n 04679 © 2022 HydroCAD Software Solutions LLC Page 3
Hydrograph for Pond 3P: Proposed Wet Pond 'A' (continued)
Time
Inflow
Storage
Elevation
Primary
(hours)
(cfs)
(cubic -feet)
(feet)
(cfs)
16.32
0.00
8,095
2,725.60
0.11
16.48
0.00
8,034
2,725.59
0.11
16.64
0.00
7,972
2,725.59
0.11
16.80
0.00
7,911
2,725.58
0.11
16.96
0.00
7,850
2,725.58
0.11
17.12
0.00
7,789
2,725.58
0.11
17.28
0.00
7,728
2,725.57
0.10
17.44
0.00
7,668
2,725.57
0.10
17.60
0.00
7,608
2,725.56
0.10
17.76
0.00
7,548
2,725.56
0.10
17.92
0.00
7,488
2,725.55
0.10
18.08
0.00
7,429
2,725.55
0.10
18.24
0.00
7,370
2,725.55
0.10
18.40
0.00
7,311
2,725.54
0.10
18.56
0.00
7,252
2,725.54
0.10
18.72
0.00
7,193
2,725.53
0.10
18.88
0.00
7,135
2,725.53
0.10
19.04
0.00
7,077
2,725.52
0.10
19.20
0.00
7,019
2,725.52
0.10
19.36
0.00
6,961
2,725.52
0.10
19.52
0.00
6,904
2,725.51
0.10
19.68
0.00
6,847
2,725.51
0.10
19.84
0.00
6,790
2,725.50
0.10
20.00
0.00
6,733
2,725.50
0.10
20.16
0.00
6,677
2,725.50
0.10
20.32
0.00
6,621
2,725.49
0.10
20.48
0.00
6,565
2,725.49
0.10
20.64
0.00
6,509
2,725.48
0.10
20.80
0.00
6,453
2,725.48
0.10
20.96
0.00
6,398
2,725.48
0.10
21.12
0.00
6,343
2,725.47
0.10
21.28
0.00
6,288
2,725.47
0.10
21.44
0.00
6,233
2,725.46
0.09
21.60
0.00
6,179
2,725.46
0.09
21.76
0.00
6,125
2,725.46
0.09
21.92
0.00
6,071
2,725.45
0.09
22.08
0.00
6,017
2,725.45
0.09
22.24
0.00
5,964
2,725.44
0.09
22.40
0.00
5,911
2,725.44
0.09
22.56
0.00
5,858
2,725.44
0.09
22.72
0.00
5,805
2,725.43
0.09
22.88
0.00
5,752
2,725.43
0.09
23.04
0.00
5,700
2,725.43
0.09
23.20
0.00
5,648
2,725.42
0.09
23.36
0.00
5,596
2,725.42
0.09
23.52
0.00
5,545
2,725.41
0.09
23.68
0.00
5,493
2,725.41
0.09
23.84
0.00
5,442
2,725.41
0.09
24.00
0.00
5,391
2,725.40
0.09
24.16
0.00
5,341
2,725.40
0.09
24.32
0.00
5,290
2,725.40
0.09

Mitchell County Middle School
12208 Stormwater Analysis Type // 24-hr 1-in. Rainfall=1.00"
Prepared by Civil Design Concepts Printed 8/9/2022
HydroCAD® 10.20-2f s/n 04679 © 2022 HydroCAD Software Solutions LLC Page 4
Hydrograph for Pond 3P: Proposed Wet Pond 'A' (continued)
Time
Inflow
Storage
Elevation
Primary
(hours)
(cfs)
(cubic -feet)
(feet)
(cfs)
24.48
0.00
5,240
2,725.39
0.09
24.64
0.00
5,190
2,725.39
0.09
24.80
0.00
5,140
2,725.38
0.09
24.96
0.00
5,091
2,725.38
0.09
25.12
0.00
5,042
2,725.38
0.09
25.28
0.00
4,993
2,725.37
0.08
25.44
0.00
4,944
2,725.37
0.08
25.60
0.00
4,896
2,725.37
0.08
25.76
0.00
4,847
2,725.36
0.08
25.92
0.00
4,799
2,725.36
0.08
26.08
0.00
4,751
2,725.36
0.08
26.24
0.00
4,704
2,725.35
0.08
26.40
0.00
4,656
2,725.35
0.08
26.56
0.00
4,609
2,725.34
0.08
26.72
0.00
4,563
2,725.34
0.08
26.88
0.00
4,516
2,725.34
0.08
27.04
0.00
4,470
2,725.33
0.08
27.20
0.00
4,423
2,725.33
0.08
27.36
0.00
4,378
2,725.33
0.08
27.52
0.00
4,332
2,725.32
0.08
27.68
0.00
4,286
2,725.32
0.08
27.84
0.00
4,241
2,725.32
0.08
28.00
0.00
4,196
2,725.31
0.08
28.16
0.00
4,152
2,725.31
0.08
28.32
0.00
4,107
2,725.31
0.08
28.48
0.00
4,063
2,725.30
0.08
28.64
0.00
4,019
2,725.30
0.08
28.80
0.00
3,975
2,725.30
0.08
28.96
0.00
3,932
2,725.29
0.08
29.12
0.00
3,888
2,725.29
0.07
29.28
0.00
3,845
2,725.29
0.07
29.44
0.00
3,803
2,725.28
0.07
29.60
0.00
3,760
2,725.28
0.07
29.76
0.00
3,718
2,725.28
0.07
29.92
0.00
3,676
2,725.27
0.07
30.08
0.00
3,634
2,725.27
0.07
30.24
0.00
3,592
2,725.27
0.07
30.40
0.00
3,551
2,725.27
0.07
30.56
0.00
3,510
2,725.26
0.07
30.72
0.00
3,469
2,725.26
0.07
30.88
0.00
3,428
2,725.26
0.07
31.04
0.00
3,388
2,725.25
0.07
31.20
0.00
3,348
2,725.25
0.07
31.36
0.00
3,308
2,725.25
0.07
31.52
0.00
3,269
2,725.24
0.07
31.68
0.00
3,229
2,725.24
0.07
31.84
0.00
3,190
2,725.24
0.07
32.00
0.00
3,151
2,725.24
0.07
32.16
0.00
3,112
2,725.23
0.07
32.32
0.00
3,074
2,725.23
0.07
32.48
0.00
3,036
2,725.23
0.07

Mitchell County Middle School
12208 Stormwater Analysis Type // 24-hr 1-in. Rainfall=1.00"
Prepared by Civil Design Concepts Printed 8/9/2022
HydroCAD® 10.20-2f s/n 04679 © 2022 HydroCAD Software Solutions LLC Page 5
Hydrograph for Pond 3P: Proposed Wet Pond 'A' (continued)
Time
Inflow
Storage
Elevation
Primary
(hours)
(cfs)
(cubic -feet)
(feet)
(cfs)
32.64
0.00
2,998
2,725.22
0.07
32.80
0.00
2,960
2,725.22
0.07
32.96
0.00
2,923
2,725.22
0.06
33.12
0.00
2,885
2,725.21
0.06
33.28
0.00
2,849
2,725.21
0.06
33.44
0.00
2,812
2,725.21
0.06
33.60
0.00
2,775
2,725.21
0.06
33.76
0.00
2,739
2,725.20
0.06
33.92
0.00
2,703
2,725.20
0.06
34.08
0.00
2,667
2,725.20
0.06
34.24
0.00
2,632
2,725.20
0.06
34.40
0.00
2,597
2,725.19
0.06
34.56
0.00
2,562
2,725.19
0.06
34.72
0.00
2,527
2,725.19
0.06
34.88
0.00
2,492
2,725.18
0.06
35.04
0.00
2,458
2,725.18
0.06
35.20
0.00
2,424
2,725.18
0.06
35.36
0.00
2,390
2,725.18
0.06
35.52
0.00
2,357
2,725.17
0.06
35.68
0.00
2,324
2,725.17
0.06
35.84
0.00
2,291
2,725.17
0.06
36.00
0.00
2,258
2,725.17
0.06
36.16
0.00
2,225
2,725.16
0.06
36.32
0.00
2,193
2,725.16
0.06
36.48
0.00
2,161
2,725.16
0.06
36.64
0.00
2,129
2,725.16
0.05
36.80
0.00
2,098
2,725.15
0.05
36.96
0.00
2,066
2,725.15
0.05
37.12
0.00
2,035
2,725.15
0.05
37.28
0.00
2,004
2,725.15
0.05
37.44
0.00
1,974
2,725.15
0.05
37.60
0.00
1,944
2,725.14
0.05
37.76
0.00
1,914
2,725.14
0.05
37.92
0.00
1,884
2,725.14
0.05
38.08
0.00
1,854
2,725.14
0.05
38.24
0.00
1,825
2,725.13
0.05
38.40
0.00
1,796
2,725.13
0.05
38.56
0.00
1,767
2,725.13
0.05
38.72
0.00
1,739
2,725.13
0.05
38.88
0.00
1,710
2,725.12
0.05
39.04
0.00
1,682
2,725.12
0.05
39.20
0.00
1,655
2,725.12
0.05
39.36
0.00
1,627
2,725.12
0.05
39.52
0.00
1,600
2,725.12
0.05
39.68
0.00
1,573
2,725.11
0.05
39.84
0.00
1,546
2,725.11
0.05
40.00
0.00
1,519
2,725.11
0.05
40.16
0.00
1,493
2,725.11
0.05
40.32
0.00
1,467
2,725.11
0.05
40.48
0.00
1,441
2,725.10
0.04
40.64
0.00
1,415
2,725.10
0.04

Mitchell County Middle School
12208 Stormwater Analysis Type // 24-hr 1-in. Rainfall=1.00"
Prepared by Civil Design Concepts Printed 8/9/2022
HydroCAD® 10.20-2f s/n 04679 © 2022 HydroCAD Software Solutions LLC Page 6
Hydrograph for Pond 3P: Proposed Wet Pond 'A' (continued)
Time
Inflow
Storage
Elevation
Primary
(hours)
(cfs)
(cubic -feet)
(feet)
(cfs)
40.80
0.00
1,390
2,725.10
0.04
40.96
0.00
1,365
2,725.10
0.04
41.12
0.00
1,340
2,725.10
0.04
41.28
0.00
1,316
2,725.09
0.04
41.44
0.00
1,292
2,725.09
0.04
41.60
0.00
1,268
2,725.09
0.04
41.76
0.00
1,244
2,725.09
0.04
41.92
0.00
1,221
2,725.09
0.04
42.08
0.00
1,197
2,725.08
0.04
42.24
0.00
1,174
2,725.08
0.04
42.40
0.00
1,152
2,725.08
0.04
42.56
0.00
1,129
2,725.08
0.04
42.72
0.00
1,107
2,725.08
0.04
42.88
0.00
1,085
2,725.08
0.04
43.04
0.00
1,063
2,725.07
0.04
43.20
0.00
1,042
2,725.07
0.04
43.36
0.00
1,021
2,725.07
0.04
43.52
0.00
1,000
2,725.07
0.04
43.68
0.00
979
2,725.07
0.03
43.84
0.00
959
2,725.07
0.03
44.00
0.00
940
2,725.06
0.03
44.16
0.00
922
2,725.06
0.03
44.32
0.00
904
2,725.06
0.03
44.48
0.00
886
2,725.06
0.03
44.64
0.00
869
2,725.06
0.03
44.80
0.00
852
2,725.06
0.03
44.96
0.00
836
2,725.06
0.03
45.12
0.00
821
2,725.06
0.03
45.28
0.00
806
2,725.05
0.03
45.44
0.00
791
2,725.05
0.03
45.60
0.00
777
2,725.05
0.02
45.76
0.00
763
2,725.05
0.02
45.92
0.00
749
2,725.05
0.02
46.08
0.00
736
2,725.05
0.02
46.24
0.00
724
2,725.05
0.02
46.40
0.00
712
2,725.05
0.02
46.56
0.00
700
2,725.05
0.02
46.72
0.00
688
2,725.04
0.02
46.88
0.00
677
2,725.04
0.02
47.04
0.00
666
2,725.04
0.02
47.20
0.00
655
2,725.04
0.02
47.36
0.00
645
2,725.04
0.02
47.52
0.00
635
2,725.04
0.02
47.68
0.00
625
2,725.04
0.02
47.84
0.00
616
2,725.04
0.02
48.00
0.00
607
2,725.04
0.02
48.16
0.00
598
2,725.04
0.02
48.32
0.00
590
2,725.04
0.01
48.48
0.00
581
2,725.04
0.01
48.64
0.00
573
2,725.04
0.01
48.80
0.00
565
2,725.03
0.01

Mitchell County Middle School
12208 Stormwater Analysis Type // 24-hr 1-in. Rainfall=1.00"
Prepared by Civil Design Concepts Printed 8/9/2022
HydroCAD® 10.20-2f s/n 04679 © 2022 HydroCAD Software Solutions LLC Page 7
Hydrograph for Pond 3P: Proposed Wet Pond 'A' (continued)
Time
Inflow
Storage
Elevation
Primary
(hours)
(cfs)
(cubic -feet)
(feet)
(cfs)
48.96
0.00
558
2,725.03
0.01
49.12
0.00
550
2,725.03
0.01
49.28
0.00
543
2,725.03
0.01
49.44
0.00
536
2,725.03
0.01
49.60
0.00
529
2,725.03
0.01
49.76
0.00
523
2,725.03
0.01
49.92
0.00
516
2,725.03
0.01
50.08
0.00
510
2,725.03
0.01
50.24
0.00
504
2,725.03
0.01
50.40
0.00
498
2,725.03
0.01
50.56
0.00
493
2,725.03
0.01
50.72
0.00
487
2,725.03
0.01
50.88
0.00
481
2,725.03
0.01
51.04
0.00
476
2,725.03
0.01
51.20
0.00
470
2,725.03
0.01
51.36
0.00
465
2,725.03
0.01
51.52
0.00
460
2,725.03
0.01
51.68
0.00
455
2,725.03
0.01
51.84
0.00
449
2,725.03
0.01
52.00
0.00
444
2,725.03
0.01
52.16
0.00
440
2,725.02
0.01
52.32
0.00
435
2,725.02
0.01
52.48
0.00
430
2,725.02
0.01
52.64
0.00
425
2,725.02
0.01
52.80
0.00
420
2,725.02
0.01
52.96
0.00
416
2,725.02
0.01
53.12
0.00
411
2,725.02
0.01
53.28
0.00
407
2,725.02
0.01
53.44
0.00
403
2,725.02
0.01
53.60
0.00
398
2,725.02
0.01
53.76
0.00
394
2,725.02
0.01
53.92
0.00
390
2,725.02
0.01
54.08
0.00
386
2,725.02
0.01
54.24
0.00
382
2,725.02
0.01
54.40
0.00
378
2,725.02
0.01
54.56
0.00
374
2,725.02
0.01
54.72
0.00
370
2,725.02
0.01
54.88
0.00
366
2,725.02
0.01
55.04
0.00
363
2,725.02
0.01
55.20
0.00
359
2,725.02
0.01
55.36
0.00
355
2,725.02
0.01
55.52
0.00
352
2,725.02
0.01
55.68
0.00
348
2,725.02
0.01
55.84
0.00
345
2,725.02
0.01
56.00
0.00
341
2,725.02
0.01
56.16
0.00
338
2,725.02
0.01
56.32
0.00
335
2,725.02
0.01
56.48
0.00
331
2,725.02
0.01
56.64
0.00
328
2,725.02
0.01
56.80
0.00
325
2,725.02
0.01
56.96
0.00
322
2,725.02
0.01

Mitchell County Middle School
12208 Stormwater Analysis Type // 24-hr 1-in. Rainfall=1.00"
Prepared by Civil Design Concepts Printed 8/9/2022
HydroCAD® 10.20-2f s/n 04679 © 2022 HydroCAD Software Solutions LLC Page 8
Hydrograph for Pond 3P: Proposed Wet Pond 'A' (continued)
Time
Inflow
Storage
Elevation
Primary
(hours)
(cfs)
(cubic -feet)
(feet)
(cfs)
57.12
0.00
319
2,725.02
0.01
57.28
0.00
316
2,725.02
0.01
57.44
0.00
313
2,725.01
0.01
57.60
0.00
310
2,725.01
0.01
57.76
0.00
307
2,725.01
0.00
57.92
0.00
304
2,725.01
0.00
58.08
0.00
302
2,725.01
0.00
58.24
0.00
299
2,725.01
0.00
58.40
0.00
296
2,725.01
0.00
58.56
0.00
294
2,725.01
0.00
58.72
0.00
291
2,725.01
0.00
58.88
0.00
288
2,725.01
0.00
59.04
0.00
286
2,725.01
0.00
59.20
0.00
283
2,725.01
0.00
59.36
0.00
281
2,725.01
0.00
59.52
0.00
279
2,725.01
0.00
59.68
0.00
276
2,725.01
0.00
59.84
0.00
274
2,725.01
0.00
60.00
0.00
272
2,725.01
0.00

APPENDIX L
1-Year Storm Event
HydroCAD Output Report

Pre Development
2S
Post Development
3P
Proposed Wet Pond 'A'
Subcat Reach on Link

MITCHELL COUNTY MIDDLE SCHOOL
12208 Stormwater Analysis Type 11 24-hr 1-yr Rainfall=3.25"
Prepared by Civil Design Concepts Printed 8/11/2022
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 2
Summary for Subcatchment 1S: Pre Development
Runoff = 8.96 cfs @ 12.03 hrs, Volume= 23,520 cf, Depth= 0.86"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 hrs, dt= 0.08 hrs
Type II 24-hr 1-yr Rainfall=3.25"
Area (sf) CN Description
2,097 98 Unconnected roofs, HSG B
224 98 Unconnected pavement, HSG B
1,932 96 Gravel surface, HSG B
96,598 61 Pasture/grassland/range, Good, HSG B
228.360 74 Pasture/arassland/ranae. Good. HSG C
329,211
70 Weighted Average
326,890
99.29% Pervious Area
2,321
0.71% Impervious Area
2,321
100.00% Unconnected
Tc
Length
Slope
Velocity Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec) (cfs)
7.7
100
0.1100
0.22
Sheet Flow,
Grass: Dense n= 0.240 P2= 2.84"
2.2
310
0.1100
2.32
Shallow Concentrated Flow,
Short Grass Pasture Kv= 7.0 fps
— — —II--III I�
9
8
7
6
N
I I I I I
I I I I I
3 5
0
LL
I I I I I
4
3
2
1 1 1 1
— r----I-- T — r
1
I I I I I
Subcatchment 1S: Pre Development
Hydrograph
I I I I I I I I I I I I I I I I I I I I I I I 1 ■Runoff
:fs F T— 1— r T— 1— 1— T—T--1--r—T--1--r—T—T--i —r—T--1--r—T—T--
1 1 -1 fiypq �1 �+-hlllr _
- 1 -1 1 1 -yrlRainfall=3.257
Ruhol'ff fea=M9I,-21 T slf -
- - hbff'Vdv11Ur-he'=23 52 III f-
_ of#_bipppthl .SWII�-
----' ----'------------'�Fo-�ngt=4,1011' -
I Slllopa=0.11100
Tcr9.9 M i n
-r-rt----IG Nr-+------r-rt----r-+----Ir-+-y----r----� 17 W /I�
1 1
I — — r — T — —I — — r — T — T — — I— — r — r — —I — — r — T
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)

MITCHELL COUNTY MIDDLE SCHOOL
12208 Stormwater Analysis Type 11 24-hr 1-yr Rainfall=3.25"
Prepared by Civil Design Concepts Printed 8/11/2022
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 3
Summary for Subcatchment 2S: Post Development
Runoff = 24.02 cfs @ 11.95 hrs, Volume= 53,748 cf, Depth= 1.96"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 hrs, dt= 0.08 hrs
Type II 24-hr 1-yr Rainfall=3.25"
Area (sf) CN Description
130,766
74
>75% Grass cover, Good, HSG C
70,431
98
Roofs, HSG C
12,919
98
Unconnected concrete, HSG C
95,055
98
Paved roads w/curbs & sewers, HSG C
3,807
98
Water Surface, HSG C
470
39
>75% Grass cover, Good, HSG A
15.763
61
>75% Grass cover. Good. HSG B
329,211 87 Weighted Average
146,999 44.65% Pervious Area
182,212 55.35% Impervious Area
12,919 7.09% Unconnected
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 2S: Post Development
Hydrograph
-+------+-+--+-+-+-+--+-+-+--+-+-+----+-+-+--+-+-+--+-+-+-+--+-+-+--
26 I Runoff
24.02 cfs_+_+__----+------+—+----r—+----+—+_+__I--r—+----r—+—+__
24 ' I I I I I I i i i i i i i i i i i i i i i i --I--I--;----I-I--I--I---I-I''T-7--I----r-r-r-7--I----T--I-I--7--I--T--I-r-T/T4i411r
22 I -yp � nr '/7-Ir T T7-I-r T-I I-T7-I--TT--I-- 1�5�'-
-
20
- --I-- + - ---- --I-- + ----I---- -I--'r Ruoo'ff+Area=�829'I,-21 1-sf-
18
I -
- - --I- - - -I- - Ru off IV61trrie-53�74 c'F
_ 16 I II II II I I I I- i- -II
14
3-1--1--I--1-�-L-1--1--I--1--I--I--L-1--I--L-1--I--L-�-J--I-�c1-5-OLlrmir� -
o =
a 12
10 ' QN=18
8 'I
6
-7------T-r -r-7------T--I--I--r-7----r-+----r-T-7----r-7----r-7-7--
4
-7--I--I -r--r-7--I--I-T------r-7----r-T----r-r-7--I-r-7----r-7-7--
2
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)

12208 Stormwater Analysis
Prepared by Civil Design Concepts
HvdroCAD® 10.00-12 s/n 04679 © 2014
MITCHELL COUNTY MIDDLE SCHOOL
Type 1124-hr 1-yrRainfall=3.25"
Printed 8/11/2022
roCAD Software Solutions LLC
Summary for Pond 3P: Proposed Wet Pond 'A'
Inflow Area =
329,211 sf,
55.35% Impervious,
Inflow Depth = 1.96" for 1-yr event
Inflow =
24.02 cfs @
11.95 hrs, Volume=
53,748 cf
Outflow =
4.53 cfs @
12.17 hrs, Volume=
51,194 cf, Atten= 81 %, Lag= 13.3 min
Primary =
4.53 cfs @
12.17 hrs, Volume=
51,194 cf
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.08 hrs / 3
Peak Elev= 2,726.76' @ 12.17 hrs Surf.Area= 16,351 sf Storage= 26,091 cf
Plug -Flow detention time= 509.8 min calculated for 51,126 cf (95% of inflow)
Center -of -Mass det. time= 485.1 min ( 1,299.3 - 814.2 )
4
Volume Invert
Avail.Storage Storage Description
#1 2,724.99'
66,384
cf Custom Stage Data (Irregular)-isted below (Recalc)
Elevation Surf.Area Perim. Voids Inc.Store Cum.Store
Wet.Area
(feet)
(sq-ft)
(feet) (%) (cubic -feet) (cubic -feet)
(sq-ft)
2,724.99
12,556
432.3 0.0 0 0
12,556
2,725.00
12,556
432.3 100.0 126 126
12,560
2,726.00
15,263
470.0 100.0 13,887 14,013
15,305
2,729.00
19,747
526.6 100.0 52,371 66,384
20,036
Device Routing
Invert
Outlet Devices
#1 Primary
2,718.50'
30.0" Round Culvert
L= 60.0' CPP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 2,718.50' / 2,718.00' S= 0.0083'/'
Cc= 0.900
n= 0.012, Flow Area= 4.91 sf
#2 Device 1
2,725.00'
2.3" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Device 1
2,726.10'
30.0" W x 8.4" H Vert. Orifice/Grate C= 0.600
#4 Device 1
2,726.80'
60.0" x 60.0" Horiz. Orifice/Grate C= 0.600
Limited to weir flow at low heads
Primary OutFlow Max=4.50 cfs @ 12.17 hrs HW=2,726.76' (Free Discharge)
L1=Culvert (Passes 4.50 cfs of 62.58 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.18 cfs @ 6.39 fps)
3=Orifice/Grate (Orifice Controls 4.31 cfs @ 2.61 fps)
4=Orifice/Grate ( Controls 0.00 cfs)

MITCHELL COUNTY MIDDLE SCHOOL
12208 Stormwater Analysis Type 11 24-hr 1-yr Rainfall=3.25"
Prepared by Civil Design Concepts Printed 8/11/2022
HvdroCAD® 10.00-12 s/n 04679 © 2014 HvdroCAD Software Solutions LLC Paae 5
Pond 3P: Proposed Wet Pond 'A'
Hyd rog raph
�'I [, Inflow
26 T-T--�--� 24.02cfs T- -i- -T-T-T--i--1--+-r----1--F r-T----1--F -r-7----1--�+-r- ❑Primary
24-I�--I�--I�-- - jnflipw a -32 11-Is
,�IIIIII IIIIIIIIIIIIIIIIIIIIIII
L 22 IIIIL I l -PeakElw;2J26.761-
-+-+-------+------+—+—+—+-+----I-c
-
yV 20� 1II
_%-_r_III-_+rPIII-_r+r_IIIa-_-_gIII-_e
18
14
-
_
'I
3
0 12-+-+------ -+------+-+------+-+-+------+-+-+------+-+-+----+-+-
LL I I I I I I I I I I I I I I I I I I I I I I I I I I I
10 +-+----I-- -+--I--I--r-+--I--I--+-+-+--I--I--r-+-+--I--I--r-+-+--I--+-+-
I I I I I I I I I I I I I I I I I I I I I I I I I I I I
i I
4.53 cfs
4 'I
—1—L--I--I— L------L-1--1----L-1—L------L-1—J--1--1--L-1—J--1--L—L-
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)

APPENDIX M
10-Year Storm Event
HydroCAD Output Report

MITCHELL COUNTY MIDDLE SCHOOL
12208 Stormwater Analysis Type/1 24-hr 10-yr Rainfall=5.80"
Prepared by Civil Design Concepts Printed 8/11/2022
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 6
Summary for Subcatchment 1S: Pre Development
Runoff = 29.67 cfs @ 12.01 hrs, Volume= 72,630 cf, Depth= 2.65"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 hrs, dt= 0.08 hrs
Type II 24-hr 10-yr Rainfall=5.80"
Area (sf) CN Description
2,097 98 Unconnected roofs, HSG B
224 98 Unconnected pavement, HSG B
1,932 96 Gravel surface, HSG B
96,598 61 Pasture/grassland/range, Good, HSG B
228.360 74 Pasture/arassland/ranae. Good. HSG C
329,211
70 Weighted Average
326,890
99.29% Pervious Area
2,321
0.71% Impervious Area
2,321
100.00% Unconnected
Tc
Length
Slope
Velocity Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec) (cfs)
7.7
100
0.1100
0.22
Sheet Flow,
Grass: Dense n= 0.240 P2= 2.84"
2.2
310
0.1100
2.32
Shallow Concentrated Flow,
Short Grass Pasture Kv= 7.0 fps
Subcatchment 1S: Pre Development
Hydrograph
—I — —' — —'— —I — L — —'— — L — 1 — —' — —'— —I — —' — —'— — L — 1 — —' — — L —I — —' — —L —I — 1 — —'— — L — — —' — — L
32 i i ■Runoff
--------- ------------------------------------------------------
29.67 cfs
30
-+--I--r-+-+--r-+----r-+-+--+-+-+----r-+-+--r-+-+--' 1i
28-L----'--+--L-1--1--1--1--1----L-L----L-1--'-- -L-L--'—
—L-L--'——L-
L-L--
26
1-0_yr-IRai nfal 11=5.$0"
24
r-r-r--Ruoff tkrea=f.�2-il- y21h sf -
-r----r-+-r-r-r----r-r----i--r iiF 22-L------1-- -L-1--1----1------L-L--
u Groff i�t�lirr�e=��� -
" 18 Rut�Of bpth''=2.05�'' U
0 16-L------+-L-L-1--1--1--1--1--'--L-L----L-1----f oT -gngth=41-O' -
14
- -=- + --7 -----
12 -Ilop�=�.1pQ��-
10-L------1-L-L-1--1--1--1--1----L-L----L-1--'--IL L __ cc =9.9Lll in
8 _---ClY#7a-
6
-+-+--+-+-+ -+-+----+-+----+-+-+----r-+----+-+-+--+-r-+----+-+-+--
4—1--1--1--1—L L-1--'--'--1--'--'--L-1--'--L-1--'--L—L-1----L—L----L-1-1--
2
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)

MITCHELL COUNTY MIDDLE SCHOOL
12208 Stormwater Analysis Type/1 24-hr 10-yr Rainfall=5.80"
Prepared by Civil Design Concepts Printed 8/11/2022
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 7
Summary for Subcatchment 2S: Post Development
Runoff = 51.23 cfs @ 11.95 hrs, Volume= 118,683 cf, Depth= 4.33"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 hrs, dt= 0.08 hrs
Type II 24-hr 10-yr Rainfall=5.80"
Area (sf) CN Description
130,766
74
>75% Grass cover, Good, HSG C
70,431
98
Roofs, HSG C
12,919
98
Unconnected concrete, HSG C
95,055
98
Paved roads w/curbs & sewers, HSG C
3,807
98
Water Surface, HSG C
470
39
>75% Grass cover, Good, HSG A
15.763
61
>75% Grass cover. Good. HSG B
329,211 87 Weighted Average
146,999 44.65% Pervious Area
182,212 55.35% Impervious Area
12,919 7.09% Unconnected
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 2S: Post Development
Hydrograph
55 Runoff
51.23 cfs _ _
So -- -I--II - -i ---I--II -- ---I- - - --I-- - - -I- - TF--- _ � �4`hir
- --I-- - - - --I-- --I- - --I- - - ' Oiyi� ga;ntat( :$01'_-
45
- - "nQfi rpa=3 9;211 T s1f -
40
-r-rt--li--Ir-+--li--Ir-r-rt--li-un-o�iff'iVQ1Lpme=li 0;603-ef -
35 II I I I I I I I I I I I I I I I I ^
30
- - -
a 25 /'► R
—+—+--+—+—+—+—+—+--+—+—+--+—+—+----+—+—+--+—+—+--+—+—+--II-
20
15
-r--I--r-+-r -r-r--I--r-r--I--r-r-r--I--r-r--I--r-r-r--r-r-r--I--r-r-r--
10
-1--1--'--+--L-1--1----+------L-1----L-+--'-- -i- ----L-1----L-1-J--
5
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)

12208 Stormwater Analysis
Prepared by Civil Design Concepts
HvdroCAD® 10.00-12 s/n 04679 © 2014
MITCHELL COUNTY MIDDLE SCHOOL
Type/1 24-hr 10-yr Rainfall=5.80"
Printed 8/11/2022
roCAD Software Solutions LLC
Summary for Pond 3P: Proposed Wet Pond 'A'
Inflow Area =
329,211 sf,
55.35% Impervious,
Inflow Depth = 4.33" for 10-yr event
Inflow =
51.23 cfs @
11.95 hrs, Volume=
118,683 cf
Outflow =
43.29 cfs @
12.00 hrs, Volume=
115,983 cf, Atten= 15%, Lag= 3.4 min
Primary =
43.29 cfs @
12.00 hrs, Volume=
115,983 cf
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.08 hrs / 3
Peak Elev= 2,727.45' @ 12.00 hrs Surf.Area= 17,366 sf Storage= 37,733 cf
Plug -Flow detention time= 253.2 min calculated for 115,983 cf (98% of inflow)
Center -of -Mass det. time= 239.1 min ( 1,030.9 - 791.8 )
E:3
Volume Invert
Avail.Storage Storage Description
#1 2,724.99'
66,384
cf Custom Stage Data (Irregular)-isted below (Recalc)
Elevation Surf.Area Perim. Voids Inc.Store Cum.Store
Wet.Area
(feet)
(sq-ft)
(feet) (%) (cubic -feet) (cubic -feet)
(sq-ft)
2,724.99
12,556
432.3 0.0 0 0
12,556
2,725.00
12,556
432.3 100.0 126 126
12,560
2,726.00
15,263
470.0 100.0 13,887 14,013
15,305
2,729.00
19,747
526.6 100.0 52,371 66,384
20,036
Device Routing
Invert
Outlet Devices
#1 Primary
2,718.50'
30.0" Round Culvert
L= 60.0' CPP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 2,718.50' / 2,718.00' S= 0.0083'/'
Cc= 0.900
n= 0.012, Flow Area= 4.91 sf
#2 Device 1
2,725.00'
2.3" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Device 1
2,726.10'
30.0" W x 8.4" H Vert. Orifice/Grate C= 0.600
#4 Device 1
2,726.80'
60.0" x 60.0" Horiz. Orifice/Grate C= 0.600
Limited to weir flow at low heads
Primary OutFlow Max=42.83 cfs @ 12.00 hrs HW=2,727.45' (Free Discharge)
L1=Culvert (Passes 42.83 cfs of 65.58 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.22 cfs @ 7.54 fps)
3=Orifice/Grate (Orifice Controls 8.38 cfs @ 4.79 fps)
4=Orifice/Grate (Weir Controls 34.23 cfs @ 2.64 fps)

MITCHELL COUNTY MIDDLE SCHOOL
12208 Stormwater Analysis Type/1 24-hr 10-yr Rainfall=5.80"
Prepared by Civil Design Concepts Printed 8/11/2022
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 9
Pond 3P: Proposed Wet Pond 'A'
Hyd rog raph
II --'I --'III--II- -I� - I� --'I--II--II--I� - I� - 'I--II--II--I� -'I --'III--II--I� - I� --'I--II--II--I� - I� - Ci Inflow
55
❑ Prima
I I I I 1I I I I I I I I I I I I I I I I I I I I I I I ry
-I--I 51.23 cfs-I--I- - - --II- --- 'llniflpw Arep-311129,�111 Illsf
50- r- r- -I--r- -r----r-r-r----r-r-r-r------r-r-r----r-r-r-r----r-r-
1
45-+—+--I 43.29 cfs Peak Elllev�2727.45'
+—I----+—+------+—+—+--I--I--+ +—+--I----+—+—+--I--+—+
40 -III t raI q=l'137,73113_cf_
,I I
--------I- --------------------------
35 - - --I------I--i - -----I--i - -----I--i -----I--i - -----I--i - -
y I I I I I I I I I I I I I I I I I I I I I I I I I I
i
j
-- 30 ,I - r- r - -
I
--I -r--I--r-r-r--I--r-r-r-r--I--I--r-r-r--I--r-r-r-r--I--r-r-
3 I I I I I I I I I I I I I I I I I I I I I I I I I I
0
FL 25-+-+--I--I -+------+-+------+-+-+-+--+-+-+-+-+--+-+-+-+----+-+-
1I I I I I I I I I I I I I I I I I I I I I I I I I I
20 - - --I--I------I-- - ------I-- - ----I-- - ------I-- - ------I-- -
15 - - --I------I--i - -----I--i - -----I--i -----I--i - -----I--i - -
1I I I I I I I I I I I I I I I I I I I I I I I I I I I
10-r-r--I--I-r----r-r-r----r-r-r-r------r-r-r----r-r-r-r----r-r-
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)

APPENDIX N
50-Year Storm Event
HydroCAD Output Report

MITCHELL COUNTY MIDDLE SCHOOL
12208 Stormwater Analysis Type 11 24-hr 50-yr Rainfall=7.94"
Prepared by Civil Design Concepts Printed 8/11/2022
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 10
Summary for Subcatchment 1S: Pre Development
Runoff = 49.46 cfs @ 12.01 hrs, Volume= 121,061 cf, Depth= 4.41"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 hrs, dt= 0.08 hrs
Type II 24-hr 50-yr Rainfall=7.94"
Area (sf) CN Description
2,097 98 Unconnected roofs, HSG B
224 98 Unconnected pavement, HSG B
1,932 96 Gravel surface, HSG B
96,598 61 Pasture/grassland/range, Good, HSG B
228.360 74 Pasture/arassland/ranae. Good. HSG C
329,211
70 Weighted Average
326,890
99.29% Pervious Area
2,321
0.71% Impervious Area
2,321
100.00% Unconnected
Tc
Length
Slope
Velocity Capacity
Description
(min)
(feet)
(ft/ft)
(ft/sec) (cfs)
7.7
100
0.1100
0.22
Sheet Flow,
Grass: Dense n= 0.240 P2= 2.84"
2.2
310
0.1100
2.32
Shallow Concentrated Flow,
Short Grass Pasture Kv= 7.0 fps
---I--I-- �� as.l,
50
45
40
35
w
U 30 I I I I
° 25
LL — j --I--j — j _ _
20
15
10
5 1 1 1 1 1
Subcatchment 1S: Pre Development
Hydrograph
I I I I I I I I I I I I I I I I I I I I I I I I ■Runoff
6cfs-------------------T -II-
I I I I i I i i I
- -----II------II-- - --II-- - --II' _ _ h�r-
$0, F a;n alb= 4f,
- - -I-- --I-- - --I-- ----------- --------------
npf Area=329,211111I sllf
Runolff Wlume=12111,016111 cllf
-'--- RuTn4 IDepfh=4.-41-"-
LI�nIg�hT4'FQ`-
-- I --II-- I--II--+-�Idple�0:111'I�©-��� -
—L-1--I--I--1--I--I--1-1--I--L-1--I--L-1—J--I--LJ—V ��VL.-�L J4LJ�—
CN-#70
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)

MITCHELL COUNTY MIDDLE SCHOOL
12208 Stormwater Analysis Type 11 24-hr 50-yr Rainfall=7.94"
Prepared by Civil Design Concepts Printed 8/11/2022
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 11
Summary for Subcatchment 2S: Post Development
Runoff = 73.98 cfs @ 11.95 hrs, Volume= 175,341 cf, Depth= 6.39"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-60.00 hrs, dt= 0.08 hrs
Type II 24-hr 50-yr Rainfall=7.94"
Area (sf) CN Description
130,766
74
>75% Grass cover, Good, HSG C
70,431
98
Roofs, HSG C
12,919
98
Unconnected concrete, HSG C
95,055
98
Paved roads w/curbs & sewers, HSG C
3,807
98
Water Surface, HSG C
470
39
>75% Grass cover, Good, HSG A
15.763
61
>75% Grass cover. Good. HSG B
329,211 87 Weighted Average
146,999 44.65% Pervious Area
182,212 55.35% Impervious Area
12,919 7.09% Unconnected
Tc Length Slope Velocity Capacity Description
(min) (feet) (ft/ft) (ft/sec) (cfs)
5.0 Direct Entry,
Subcatchment 2S: Post Development
Hydrograph
80 Runoff
1 73. 18 cfs ( 1
75 / 1-r--1--1--+ , r-r--1--1--T--1--r-r-r——1-1--r-T--1--r-T-r--�Tyh'1e-0-94-�Ir-
70— + — —I— —I— —+— --—+--I----+--I--I--+—+—--+—+--1 --+—+----r— --
65 Oyyr F a,n alb= 4 �
----------- -------------------------------------------------------
60 ,1Ljnpfrga=39r21� 1
— T — — — 7 T —I — — r — T — — — — — — Y — — — — — - r - r - I_ r -
55 ' 1 ---11--1--+- - ---11--11--+--11--11-- ---11-Ru olff VQ1 piT a=1,75,3�F 1; -eIf -
50 1 1 1 1 1 1 1 1
----------------
w 45 - + - -1- u In Q le p
w
,1
1-�--1--1--T-�-r-�--1--1--r--1--r-r-�--1--r-+--1--r-r-r--I--IrTT-7--ICC--r-�-r--
0 40-1--1--1--+--L-1--1--1--1--1--1--L-1--1--L-+--1--1 i __L' C=15•_Q �un -
- I I I I�•► �I � �1 1
a 35 -CN=w 8�
- ------ -- -1-- ------ ------ 1-- --- 1Y�
30
-r--1--r-+-r -r-r--1--r-r--1--r-r-r--1--r-r--1--r-r-r----r-r--1--r-r-r--
'1
25-1--1--1--+--L-1--1--1--1--1--1--L-1--1--L-1--1--L-1-J--1--L---1--L-1-J--
20
15
'1
10-1--1--1--+- -L-1--1--1--1--1--1--L-1--1--L-1--1--L-1-J--1--L-1--1--L-1-J--
5 1 1 1 1 1 1 1 1 1 I 1 1 1 I I I I
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)

MITCHELL COUNTY MIDDLE SCHOOL
12208 Stormwater Analysis Type 11 24-hr 50-yr Rainfall=7.94"
Prepared by Civil Design Concepts Printed 8/11/2022
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC Page 12
Summary for Pond 3P: Proposed Wet Pond 'A'
Inflow Area = 329,211 sf, 55.35% Impervious, Inflow Depth = 6.39" for 50-yr event
Inflow = 73.98 cfs @ 11.95 hrs, Volume= 175,341 cf
Outflow = 65.74 cfs @ 11.99 hrs, Volume= 172,500 cf, Atten= 11 %, Lag= 2.6 min
Primary = 65.74 cfs @ 11.99 hrs, Volume= 172,500 cf
Routing by Stor-Ind method, Time Span= 0.00-60.00 hrs, dt= 0.08 hrs / 3
Peak Elev= 2,727.71' @ 11.99 hrs Surf.Area= 17,742 sf Storage= 42,134 cf
Plug -Flow detention time= 182.4 min calculated for 172,270 cf (98% of inflow)
Center -of -Mass det. time= 174.8 min ( 955.8 - 781.0 )
Volume Invert Avail.Storage Storage Description
#1 2,724.99' 66,384 cf Custom Stage Data (Irregular)-isted below (Recalc)
Elevation Surf.Area Perim. Voids Inc.Store Cum.Store Wet.Area
(feet) (sq-ft) (feet) (%) (cubic -feet) (cubic -feet) (sq-ft)
2,724.99 12,556 432.3 0.0 0 0 12,556
2,725.00 12,556 432.3 100.0 126 126 12,560
2,726.00 15,263 470.0 100.0 13,887 14,013 15,305
2,729.00 19,747 526.6 100.0 52,371 66,384 20,036
Device Routing Invert Outlet Devices
#1 Primary 2,718.50' 30.0" Round Culvert
L= 60.0' CPP, square edge headwall, Ke= 0.500
Inlet / Outlet Invert= 2,718.50' / 2,718.00' S= 0.0083'/' Cc= 0.900
n= 0.012, Flow Area= 4.91 sf
#2 Device 1 2,725.00' 2.3" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Device 1 2,726.10' 30.0" W x 8.4" H Vert. Orifice/Grate C= 0.600
#4 Device 1 2,726.80' 60.0" x 60.0" Horiz. Orifice/Grate C= 0.600
Limited to weir flow at low heads
Primary OutFlow Max=64.09 cfs @ 11.99 hrs HW=2,727.69' (Free Discharge)
L1=Culvert (Passes 64.09 cfs of 66.58 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.23 cfs @ 7.89 fps)
3=Orifice/Grate (Orifice Controls 9.34 cfs @ 5.33 fps)
4=Orifice/Grate (Weir Controls 54.53 cfs @ 3.08 fps)

MITCHELL COUNTY MIDDLE SCHOOL
12208 Stormwater Analysis Type 11 24-hr 50-yr Rainfall=7.94"
Prepared by Civil Design Concepts Printed 8/11/2022
HvdroCAD® 10.00-12 s/n 04679 © 2014 HvdroCAD Software Solutions LLC Paae 13
Pond 3P: Proposed Wet Pond 'A'
Hyd rog raph
�4
■Inflow
80
+
-1-L--'--'
--1--1--L-1----'--
73.98 cfs
-L-L------L-L-J------L-1-J--1--L-L-
❑Prima
Primary
75
„---;----,--,
--,--,--,----;--,--,--,----1nf1pW-,
rea+329-,Z14-sf-
70
-T-
--II-- - -T----
65.74 cfs
+
-T-T--II----T-T-T--II--F-7-7-7
-+
+ + +
T-7-7----F-T-
r
+ Peak Ell-v�2 7-27,71+-
65
60
,�
-L---'--'-
-L--'----L-1--1--1--L-L---'--I_
+ J I_ I_ + L
rage , -� �� -
55
-;
- --,------,--;
-; -
T-
----,--; -;
T------
-----,--; -----,--; -; -----,--; -; -
50
��I
-T-
----' - ----
-
F-T
-T------T -T- -----T-T-T----T-T-
I I 1
45
....
1 1
+_+__,_-,-_+_+_+__,__,__+_+_+__,__,__+_+_+__,__+_+_
40-
0
-1-L--I--'
-J--'--'--L-1--1--'--L-L-1--'----L-1-J--1--1--L-1-J--1--L-L-
T-
T----r-T
F TT- T--r-T-
30
-T-T--i--i
- ---T-T-
F
-T- --- -T----T-T- F
25
20
-1-L--'--'
-J--1--1--L-1--1--'--L-L-1--'----L-1-J--1--1--L-1-J--1--L-L-
T
-T-
--i--i----T-T-
------F-
-------r-T- ----T-T-I-T----F-T-
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60
Time (hours)