20220398 Ver 2_12208 Hydro Report_Reduced_20220926

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

ENGINEER

Michael Cain, PE

August 30, 2022
Rev: Sept. 23, 2022

168 Patton Avenue, Asheville, NC 28801
828-252-5388
TABLE OF CONTENTS

ITEM/DESCRIPTION PAGE NO.

1.0 Project 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 FIRMette 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 Page 1
Mitchell County Middle School
1.0 INTRODUCTION

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;Tr” 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 Page 2
Mitchell County Middle School
3.0 STORMWATER ANALYSIS

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 (D avg):

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 Page 3
Mitchell County Middle School

When using a Davg 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 Page 4
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.

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

SEE FI5 REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT
82°721"W 35°58'12"N
Without Base Flood Elevation (BFE)
Zone A. V. A99
With BFE or Depth zone AE. AO. AP, vF, AR
Regulatory Floodway
SCREEN Area of Minimal Flood Hazard
th
Digital Data Available
No Digital Data Available
Area with Flood Risk due to Leveez
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APPENDIX B

USDA NRCS Soils Report

United States
Department of
Agriculture
A product of the National
Cooperative Soil Survey,
a joint effort of the United
States Department of
Agriculture and other
Federal agencies, State
agencies including the
Agricultural Experiment
Stations, and local
participants
Custom Soil Resource
Report for
Mitchell County,
North Carolina
Mitchell County Middle School
Natural
Resources
Conservation
Service
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.nrcs.usda.gov/wps/
portal/nrcs/main/soils/health/) and certain conservation and engineering
applications. For more detailed information, contact your local USDA Service Center
(https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil
Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/?
cid=nrcs142p2_053951).
Great differences in soil properties can occur within short distances. Some soils are
seasonally wet or subject to flooding. Some are too unstable to be used as a
foundation for buildings or roads. Clayey or wet soils are poorly suited to use as
septic tank absorption fields. A high water table makes a soil poorly suited to
basements or underground installations.
The National Cooperative Soil Survey is a joint effort of the United States
Department of Agriculture and other Federal agencies, State agencies including the
Agricultural Experiment Stations, and local agencies. The Natural Resources
Conservation Service (NRCS) has leadership for the Federal part of the National
Cooperative Soil Survey.
Information about soils is updated periodically. Updated information is available
through the NRCS Web Soil Survey, the site for official soil survey information.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its
programs and activities on the basis of race, color, national origin, age, disability,
and where applicable, sex, marital status, familial status, parental status, religion,
sexual orientation, genetic information, political beliefs, reprisal, or because all or a
part of an individual's income is derived from any public assistance program. (Not
all prohibited bases apply to all programs.) Persons with disabilities who require
2
alternative means for communication of program information (Braille, large print,
audiotape, etc.) should contact USDA's TARGET Center at [phone] (voice
and TDD). To file a complaint of discrimination, write to USDA, Director, Office of
Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or
call [phone] (voice) or [phone] (TDD). USDA is an equal opportunity
provider and employer.
3
Contents
Preface....................................................................................................................2
Soil Map..................................................................................................................5
Soil Map................................................................................................................6
Legend..................................................................................................................7
Map Unit Legend..................................................................................................8
Map Unit 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
4
Soil Map
The soil map section includes the soil map for the defined area of interest, a list of
soil map units on the map and extent of each map unit, and cartographic symbols
displayed on the map. Also presented are various metadata about data used to
produce the map, and a description of each soil map unit.
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6
Custom Soil Resource Report
Soil Map
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399100 399150 399200 399250 399300 399350 399400
399100 399150 399200 399250 399300 399350 399400
35° 58' 5'' N
82
°

7
'

9
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W
35° 58' 5'' N
82
°

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N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 17N WGS84
0 100 200 400 600
Feet
0 30 60 120 180
Meters
Map Scale: 1:2,200 if printed on A portrait (8.5" x 11") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Map Unit Polygons
Soil Map Unit Lines
Soil Map Unit Points
Special Point Features
Blowout
Borrow Pit
Clay Spot
Closed Depression
Gravel Pit
Gravelly Spot
Landfill
Lava Flow
Marsh or swamp
Mine or Quarry
Miscellaneous Water
Perennial Water
Rock Outcrop
Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
Sodic Spot
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:12,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: 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.
Custom Soil Resource Report
7
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
BdA Bandana sandy loam, 0 to 3
percent slopes, occasionally
flooded
3.0 19.7%
EcC Evard-Cowee complex, central
mountains, 8 to 15 percent
slopes
4.0 26.1%
EcD Evard-Cowee complex, central
mountain, 15 to 30 percent
slopes, stony
1.6 10.6%
EdE Evard-Cowee complex, central
mountain, 30 to 50 percent
slopes, stony
0.3 1.7%
SaB Saunook silt loam, 2 to 8
percent slopes
3.0 19.8%
ScC Saunook silt loam, 8 to 15
percent slopes, stony
2.3 14.8%
Ud Udorthents, loamy 1.1 7.4%
Totals for Area of Interest 15.4 100.0%
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
8
are identified by a special symbol on the maps. If included in the database for a
given area, the contrasting minor components are identified in the map unit
descriptions along with some characteristics of each. A few areas of minor
components may not have been observed, and consequently they are not
mentioned in the descriptions, especially where the pattern was so complex that it
was impractical to make enough observations to identify all the soils and
miscellaneous areas on the landscape.
The presence of minor components in a map unit in no way diminishes the
usefulness or accuracy of the data. The objective of mapping is not to delineate
pure taxonomic classes but rather to separate the landscape into landforms or
landform segments that have similar use and management requirements. The
delineation of such segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, however,
onsite investigation is needed to define and locate the soils and miscellaneous
areas.
An identifying symbol precedes the map unit name in the map unit descriptions.
Each description includes general facts about the unit and gives important soil
properties and qualities.
Soils that have profiles that are almost alike make up a soil series. Except for
differences in texture of the surface layer, all the soils of a series have major
horizons that are similar in composition, thickness, and arrangement.
Soils of one series can differ in texture of the surface layer, slope, stoniness,
salinity, degree of erosion, and other characteristics that affect their use. On the
basis of such differences, a soil series is divided into soil phases. Most of the areas
shown on the detailed soil maps are phases of soil series. The name of a soil phase
commonly indicates a feature that affects use or management. For example, Alpha
silt loam, 0 to 2 percent slopes, is a phase of the Alpha series.
Some map units are made up of two or more major soils or miscellaneous areas.
These map units are complexes, associations, or undifferentiated groups.
A complex consists of two or more soils or miscellaneous areas in such an intricate
pattern or in such small areas that they cannot be shown separately on the maps.
The pattern and proportion of the soils or miscellaneous areas are somewhat similar
in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example.
An association is made up of two or more geographically associated soils or
miscellaneous areas that are shown as one unit on the maps. Because of present
or anticipated uses of the map units in the survey area, it was not considered
practical or necessary to map the soils or miscellaneous areas separately. The
pattern and relative proportion of the soils or miscellaneous areas are somewhat
similar. Alpha-Beta association, 0 to 2 percent slopes, is an example.
An undifferentiated group is made up of two or more soils or miscellaneous areas
that could be mapped individually but are mapped as one unit because similar
interpretations can be made for use and management. The pattern and proportion
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
9
Mitchell County, North Carolina
BdA—Bandana sandy loam, 0 to 3 percent slopes, occasionally flooded
Map Unit Setting
National map unit symbol: lcrj
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
Custom Soil Resource Report
10
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
Custom Soil Resource Report
11
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
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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
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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
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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
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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
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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.
Custom Soil Resource Report
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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
Custom Soil Resource Report
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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
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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: lcth
Elevation: 1,150 to 6,180 feet
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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
Custom Soil Resource Report
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References
American Association of State Highway and Transportation Officials (AASHTO).
2004. Standard specifications for transportation materials and methods of sampling
and testing. 24th edition.
American Society for Testing and Materials (ASTM). 2005. Standard classification of
soils for engineering purposes. ASTM Standard D2487-00.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of
wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife
Service FWS/OBS-79/31.
Federal Register. July 13, 1994. Changes in hydric soils of the United States.
Federal Register. September 18, 2002. Hydric soils of the United States.
Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric
soils in the United States.
National Research Council. 1995. Wetlands: Characteristics and boundaries.
Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service.
U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/national/soils/?cid=nrcs142p2_054262
Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for
making and interpreting soil surveys. 2nd edition. Natural Resources Conservation
Service, U.S. Department of Agriculture Handbook 436. http://
www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577
Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of
Agriculture, Natural Resources Conservation Service. http://
www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580
Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and
Delaware Department of Natural Resources and Environmental Control, Wetlands
Section.
United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of
Engineers wetlands delineation manual. Waterways Experiment Station Technical
Report Y-87-1.
United States Department of Agriculture, Natural Resources Conservation Service.
National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/
home/?cid=nrcs142p2_053374
United States Department of Agriculture, Natural Resources Conservation Service.
National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/
detail/national/landuse/rangepasture/?cid=stelprdb1043084
22
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/
nrcs/detail/soils/scientists/?cid=nrcs142p2_054242
United States Department of Agriculture, Natural Resources Conservation Service.
2006. Land resource regions and major land resource areas of the United States,
the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook
296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?
cid=nrcs142p2_053624
United States Department of Agriculture, Soil Conservation Service. 1961. Land
capability classification. U.S. Department of Agriculture Handbook 210. http://
www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf
Custom Soil Resource Report
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APPENDIX C

NOAA Rainfall Data

3/14/22, 11:47 AM Precipitation Frequency Data Server
NOAA Atlas 14, Volume 2, Version 3
Location name: Bakersville, North Carolina, USA*
Latitude: 35.9659°, Longitude: -82.1172°
Elevation: 2737.18 ft**
* source: ESRI Maps
** source: USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring, Maryland
PF tabular I PF graphical I Maps & aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches/hour)1
Duration
Average recurrence interval (years)
1
2
5
10
25
50 100 200
500 1000
5-min
4.42
(4.03-4.85)
5.27
(4.81-5.78)
6.23
(5.68-6.84)
6.98
(6.35-7.67)
7.99
(7.21-8.78)
8.76
(7.85-9.65)
9.54
(8.47-10.5)
10.3
(9.10-11.5)
11.4
(9.86-12.8)
12.3
(10.5-13.8)
10-min
_
3.52
(3.22-3.88)
4.21
(3.85-4.63)
4.99
(4.54-5.48)
5.59
(5.08-6.13)
6.37
(5.75-7.00)
6.97
(6.25-7.68)
7.58
(6.73-8.37)
8.20
(7.21-9.10)
9.02
(7.80-10.1)
9.66
(8.24-10.9)
15-min
2.94
(2.68-3.23)
3.53
(3.23-3.88)
4.21
(3.83-4.62)
4.71
(4.28-5.17)
5.38
(4.86-5.91)
5.88
(5.27-6.48)
6.39
(5.68-7.05)
6.89
(6.06-7.66)
7.57 I
(6.55-8.46)
8.08
(6.89-9.11)
30-min
2.01
(1.84-2.21)
2.44
(2.23-2.68)
2.99
(2.72-3.28)
3.41
(3.10-3.74)
3.98
(3.60-4.38)
4.43
(3.97-4.88)
4.89
(4.35-5.40)
5.37 I
(4.72-5.96)
6.02
(5.21-6.73)
6.54
(5.58-7.38)
60-min
1.25
(1.15-1.38)
1.53
(1.40-1.68)
1.92
(1.74-2.10)
2.22
(2.02-2.44)
2.65
(2.39-2.92)
3.00
(2.69-3.31)
3.37
(2.99-3.72)
3.76
(3.31-4.18) I
4.32
(3.74-4.83) I
4.78
(4.07-5.39)
2-hr
0.720
(0.656-0.790)
0.880
(0.800-0.966)
1.11
(1.01-1.22)
1.31
(1.18-1.43)
1.58
(1.42-1.73)
1.81
(1.61-1.99)
2.06
(1.82-2.27)
2.33
(2.03-2.58)
2.72
(2.33-3.04)
3.06
(2.58-3.45)
3-hr
0.521
(0.475-0.574)
0.632
(0.577-0.697)
0.796
(0.725-0.877)
0.932
(0.845-1.03)
1.14
(1.02-1.25)
1.31
(1.16-1.44)
1.49
(1.31-1.66)
1.70
(1.48-1.90)
2.01
(1.71-2.26)
2.28
(1.91-2.58)
6-hr
0.334
(0.307-0.364)
0.402
(0.370-0.439)
0.498
(0.456-0.544)
0.579
(0.528-0.632)
0.700
(0.633-0.765)
0.804
(0.721-0.881)
0.918
(0.813-1.01)
1.05
(0.914-1.16)
1.24
(1.06-1.38)
1.40
(1.18-1.58)
12-hr
0.212
(0.196-0.230)
0.256
(0.236-0.278)
0.315
(0.290-0.343)
0.362
(0.332-0.394)
0.429
(0.392-0.468)
0.484
(0.439-0.530),
0.542
(0.488-0.596)
0.605
(0.539-0.669)
0.695
(0.611-0.776)
0.772
(0.670-0.869)
24-hr
0.135
(0.123-0.150)
0.164
(0.149-0.182)
0.207
(0.188-0.230)
0.242
(0.219-0.269)
0.290
(0.261-0.324)
0.331 0.373
(0.295-0.370) (0.331-0.419)
0.419
(0.368-0.472)
0.484
(0.419-0.549)
0.538
(0.460-0.615)
2-day
0.081
(0.074-0.089)
0.098
(0.090-0.107)
0.123
(0.113-0.135)
0.143
(0.131-0.158)
0.172
(0.155-0.189)
0.196 0.221
(0.176-0.216)1 (0.196-0.245)
0.247
(0.218-0.276)
0.286
(0.248-0.321)
0.317
(0.272-0.360)
3-day
0.058
(0.053-0.063)
0.070
(0.064-0.076)
0.087
(0.080-0.096)
0.101
(0.092-0.111)
0.120
(0.109-0.132)
0.136
(0.123-0.150)
0.153
(0.137-0.169)
0.171
(0.151-0.190)
0.196
(0.171-0.220)
0.217
(0.187-0.246)
4-day
0.046
(0.043-0.051)
0.056
(0.051-0.061)
0.069
(0.063-0.076)
0.080
(0.073-0.087)
0.095
(0.086-0.104)
0.107
(0.096-0.118)
0.119
(0.107-0.132)
0.133
(0.118-0.147)
0.151
(0.133-0.169)
0.167
(0.145-0.189)
7-day
0.031
(0.028-0.034)
0.037
(0.034-0.040)
0.045
(0.041-0.049)
0.051
(0.047-0.057)
0.060
(0.055-0.066)
0.067
(0.061-0.074)
0.075
(0.067-0.083)
0.082
(0.073-0.092)
0.093
(0.082-0.105)
0.101
(0.088-0.115)
10-day
0.025
(0.023-0.027)
0.029
(0.027-0.032)
0.035
(0.033-0.039)
0.040
(0.037-0.044)
0.046
(0.042-0.051)
0.051 I 0.056
(0.046-0.056) (0.051-0.062)
0.061
(0.055-0.067)
0.068
(0.060-0.076)
0.074
(0.065-0.083)
20-day
0.017
(0.015-0.018)
0.020
(0.018-0.021)
0.023
(0.022-0.025)
0.026
(0.024-0.028)
0.030
(0.027-0.032)
0.033 0.036
(0.030-0.035) (0.033-0.039)
0.039
(0.035-0.042)
0.043
(0.039-0.047)
0.046
(0.041-0.051)
30-day
0.014
(0.013-0.015)
0.016
(0.015-0.017)
0.019
(0.017-0.020)
0.021
(0.019-0.022)
0.023
(0.022-0.025)
0.025
(0.023-0.027)
0.027
(0.025-0.029)
0.029
(0.027-0.031)
0.032
(0.029-0.034)
0.033
(0.030-0.037)
45-day 0.011
(0.011-0.012)
0.013
(0.013-0.014)
0.015
(0.014-0.016)
0.017
(0.016-0.018)
0.019
(0.017-0.020)
0.020
(0.019-0.021)
0.021
(0.020-0.023)
0.023
(0.021-0.024)
0.025
(0.023-0.026)
0.026
(0.024-0.028)
60-day 0.010
i (0.010-0.011)
0.012
(0.011-0.013)
0.014
(0.013-0.014)
0.015
(0.014-0.016)
0.016
(0.015-0.017)
0.017
(0.016-0.018)
0.019
(0.017-0.020)
0.020
(0.018-0.021)
0.021
(0.019-0.022)
0.022
(0.020-0.024)
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/hdsc/pfds/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
Location name: Bakersville, North Carolina, USA*
Latitude: 35.9659°, Longitude: -82.1172°
Elevation: 2737.18 ft**
* source: ESRI Maps
** source: USGS
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley
NOAA, National Weather Service, Silver Spring, Maryland
PF tabular I PF graphical I Maps & aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1
Duration
Average recurrence interval (years)
1
2 5
10
25
50
100 200
500 1000
5-min
0.368
(0.336-0.404)
0.439
(0.401-0.482)
0.519
(0.473-0.570)
0.582
(0.529-0.639)
0.666
(0.601-0.732)
0.730
(0.654-0.804)
0.795
(0.706-0.878)
0.862
(0.758-0.957)
0.950
(0.822-1.06)
1.02
(0.872-1.15)
10-min
0.587
(0.536-0.646)
0.702
(0.642-0.771)
0.832
(0.757-0.913)
0.931
(0.846-1.02)
1.06
(0.958-1.17)
1.16
(1.04-1.28)
1.26
(1.12-1.40)
1.37
(1.20-1.52)
1.50
(1.30-1.68)
1.61
(1.37-1.82)
15-min
0.734
(0.670-0.807)
0.882
(0.807-0.969)
1.05
(0.957-1.16)
1.18
(1.07-1.29)
1.35
(1.21-1.48)
1.47
(1.32-1.62)
1.60
(1.42-1.76)
1.72
(1.52-1.91)
1.89
(1.64-2.12)
2.02
(1.72-2.28)
30-min
1.01
(0.919-1.11)
1.22
(1.11-1.34)
1.49
(1.36-1.64)
1.71
(1.55-1.87)
1.99
(1.80-2.19)
2.22
(1.99-2.44)
2.45
(2.17-2.70)
2.68
(2.36-2.98)
3.01
(2.61-3.37)
3.27
(2.79-3.69)
60-min
1.25
(1.15-1.38)
1.53
(1.40-1.68)
1.92
(1.74-2.10)
2.22
(2.02-2.44)
2.65
(2.39-2.92)
3.00
(2.69-3.31)
3.37
(2.99-3.72)
3.76
(3.31-4.18)
4.32
(3.74-4.83)
4.78
(4.07-5.39)
2-hr
1.44
(1.31-1.58)
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)
3-hr
1.56
(1.43-1.73)
1.90
(1.73-2.09)
2.39
(2.18-2.63)
2.80
(2.54-3.08)
3.41
(3.06-3.75)
3.92
(3.49-4.34)
4.48
(3.95-4.97)
5.11
(4.44-5.70)
6.04
(5.14-6.79)
6.84
(5.74-7.76)
6-hr
2.00
(1.84-2.18)
2.41
(2.21-2.63)
2.98
(2.73-3.26)
3.47
(3.16-3.78)
4.19
(3.79-4.58)
4.82
(4.32-5.27)
5.50
(4.87-6.05)
6.26
(5.47-6.93)
7.40
(6.34-8.27)
8.39
(7.06-9.45)
12-hr
2.56
(2.36-2.78)
3.09
(2.85-3.35)
3.80
(3.49-4.13)
4.36
(4.01-4.75)
5.17
(4.72-5.64)
5.83
(5.29-6.38)
6.53
(5.88-7.18)
7.29
(6.49-8.06)
8.37
(7.36-9.35)
9.30
(8.07-10.5)
24-hr
3.25
(2.96-3.61)
3.93
(3.58-4.37)
4.97
(4.51-5.52)
5.80
(5.25-6.45)
6.97
(6.27-7.77)
7.94
(7.09-8.87)
8.96
(7.94-10.1)
10.1
(8.82-11.3)
11.6
(10.1-13.2)
12.9
(11.0-14.8)
2-day
3.90
(3.57-4.27)
4.70
(4.31-5.16)
5.91
(5.41-6.49)
6.89
(6.27-7.56)
8.26
(7.46-9.09)
9.39
(8.43-10.4)
10.6
(9.43-11.7)
11.9
(10.5-13.2)
13.7
(11.9-15.4)
15.2
(13.0-17.3)
3-day
4.17
(3.83-4.57)
5.03
(4.61-5.51)
6.27
(5.74-6.88)
7.27
(6.63-7.97)
8.67
(7.85-9.53)
9.82
(8.83-10.8)
11.0
(9.84-12.2)
12.3
(10.9-13.7)
14.1
(12.3-15.8)
15.6
(13.5-17.7)
4-day
4.45
(4.09-4.87)
5.35
(4.92-5.85)
6.64
(6.08-7.26)
7.66
(7.00-8.38)
9.09
(8.25-9.97)
10.2
(9.24-11.3)
11.5
(10.2-12.7)
12.7
(11.3-14.1)
14.5 16.1
(12.7-16.3) (13.9-18.1)
7-day
5.16
(4.76-5.67)
6.17
(5.70-6.78)
7.54
(6.94-8.29)
8.62
(7.92-9.49)
10.1
(9.23-11.2)
11.3
(10.2-12.5)
12.5
(11.3-13.9)
13.8
(12.3-15.4)
15.6
(13.7-17.6)
17.0
(14.8-19.3)
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)
13.4
(12.1-14.8)
14.6
(13.2-16.2)
16.2
(14.5-18.2) I
17.6
(15.6-19.9)
20-day
7.94
(7.42-8.56)
9.39
(8.76-10.1)
11.1
(10.3-12.0)
12.4
(11.6-13.4)
14.2
(13.2-15.4)
15.7
(14.4-17.0)
17.1
(15.7-18.6)
18.6
(16.9-20.3)
20.5 I
(18.5-22.6)
22.1
(19.8-24.4)
30-day
9.81
(9.21-10.5)
11.6
(10.8-12.4)
13.4
(12.6-14.4)
14.8
(13.9-15.9)
16.7
(15.5-17.9)
18.1
(16.8-19.5)
19.5
(18.0-21.1)
20.9
(19.2-22.7)
22.7 24.1
(20.7-24.8) (21.8-26.5)
45-day
12.4
(11.7-13.1)
14.5
(13.7-15.3)
16.5
(15.6-17.5)
18.0
(17.0-19.1)
20.1
(18.9-21.3)
21.6
(20.3-23.0)
23.1
(21.6-24.7)
24.6
(22.8-26.3)
26.5
(24.5-28.5)
27.9
(25.6-30.2)
60-day
14.8
(14.0-15.6)
17.2
(16.3-18.2)
19.5
(18.4-20.6)
21.2
(20.1-22.4)
23.4
(22.1-24.8)
25.1
(23.6-26.6)
26.7
(25.0-28.4)
28.2
(26.4-30.1)
30.2
(28.0-32.4)1
31.6
(29.3-34.1)
t 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/hdsc/pfds/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
NOM
0' 100'
BYPASS AREA
(YELLOW) 0.11 AC
TEMPORARY DITCH 'B'
DRAINAGE AREA: 0.45 AC
OFFSITE CLEAN
WATER BYPASS
AREA 38.4 Ac
Civi
Design
Concepts, PA
NCBELS #: C-2184
err;
I
v A \ A I l
4\ II I ,I/
\/ j ) // /) / // / / / /;
/ // / ////�//i/1
/,// ////�// \ --�/
/ / / /__ -\
BYPASS AREA
(YELLOW) 1.46 AC
TEMPORARY DITCH 'A2'
DRAINAGE AREA: 6.78 AC
1
l
7
NN
PP
7
\ 1
— —1 7
/ l 1
/—
/
// / /
/ \ /
/1
1\ \ I
v� I�/A V A
v jI v
/
/
i� �/� 7- \
/ `/ /
I /7 i
\ vv vv v
i7 vim`
soofb
TEMPORARY DITCH 'C'
DRAINAGE AREA: 4.72 AC
/
0?`
%'///// �' d \ IV A ( I
��/j///// / v \ V A \
///\///�� \ \ \ \ \ \
/// % / \ \ \ \ \ \\
\ \\\�
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7-
7
i
---
7-
/
—
/
— //
i
// /
/
\ \ \ \
7—
7—
/
\
\\ \v \v\\ \ �\ \\'\11" i
II/1 /1 v
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\\\\ \ \ \\ 1 y I JI I \
\\ ` \ \\ \ \ \ \ �I I I �`,�.
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\ \ \ \
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\ \ \� \ \ \ \ " \ \\ '\/
V A V` A A \\ V
\ \ \ \ \ \
v A V A �
\ \ ^ \ A \ \
\\ \\ \A \\ ■I\
\
7-
/
SKIMMER 'A' DRAINAGE
AREA 9.37 AC
1
TEMPORARY DITCH 'Al'
DRAINAGE AREA: 2.59 AC
MITCHELL COUNTY COUNTY MIDDLE SCHOOL
EROSION CONTROL DRAINAGE BULLETIN
AUGUST 2022

N OSTN
0'
100'
•
Ji P
Tm� 3
Boa
YEN `�s w
V � r
mi
Q
a
RCP
EXISTING 2' CONTOURS
Y
EXISTING PROPERTY LINE (TYP)
Civil
ig Desn
Concepts, PA
NCBELS #: C-2184
\
established within traditionary
maintained area \ a' aa.a
aza_
0
g
oao / y
mNN /
H m n
0.
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O
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MITCHELL COUNTY COUNTY MIDDLE SCHOOL
PRE DEVELOPMENT DRAINAGE BULLETIN
AUGUST 2022

N OM
0' 100'
Sao
2 v
o
on o
d01,1sifr?7
Orn;
Cr) RY RR
mo
d
RCP
1:f3W40:0-
WETPOND "A"
(TOTAL DRAINAGE AREA 7.56 AC.)
EXISTING PROPERTY LINE (TYP)
Civi
Design
Concepts, PA
NCBELS #: C-2184
0\ 0
1
established within traditionally
maintained area
a.. se.,
e4 hs.,W'3S�?I
Double bellow— __7 ----- J
mj
0
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/_
PROPOSED WETPOND 'A'
PROPOSED 2' CONTOURS
EXISTING 2' CONTOURS
MITCHELL COUNTY COUNTY MIDDLE SCHOOL
POST DEVELOPMENT DRAINAGE BULLETIN
AUGUST 2022

'H
0' 100'
Fisgnpts,PA
NCBELS #C-2184
6]
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MITCHELL COUNTY COUNTY MIDDLE SCHOOL
STRUCTURE DRAINAGE AREA BULLETIN
SEPTEMBER 2022

APPENDIX E

Skimmer Basin Design Calculations
D C Civil
Design
Concepts, PA
MITCHELL COUNTY MIDDLE SCHOOL
CDC Project 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 (IIo)
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
29x1.5
feet
Water Depth
0.49
feet
Free -Board
1.01
feet
NCDENR E&SC Manual (Ch 6.6)
Weighted Coefficient
at TC
2:1 Min, 6:1 Max
2' min for Skimmer & Basin
= Lt - 2 (Slope x Depth)
= Wt - 2 (Slope x Depth)
=DAxCx1
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

Rainfall not specifiedSkimmer Basin - Storage
Printed 8/29/2022Prepared by Civil Design Concepts
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC
Summary for Pond 1P: Skimmer A (1)
[43] Hint: Has no inflow (Outflow=Zero)
Volume Invert Avail.Storage Storage Description
#1 2,722.00' 8,052 cf Custom Stage Data (Irregular) Listed 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
Rainfall not specifiedSkimmer Basin - Storage
Printed 8/29/2022Prepared by Civil Design Concepts
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.Storage Storage Description
#1 2,722.00' 20,619 cf Custom Stage Data (Irregular) Listed 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
Mitchell Middle School
CDC Project No.: 12208
DITCH RUNOFF "C" 10-YEAR INTENSITY (IN/HR)
DRAINAGE
AREA (AC)FLOWRATE (CFS)
TEMPORARY DITCH A1 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
DITCH CALCULATIONS
FLOWRATE CALCULATIONS
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 ECMDS 7.0
https://ecmds.com/project/151501/channel-analysis/231746/show 1/1
North American Green
5401 St. Wendel-Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v7.0
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
Phase Reach Discharge Velocity Normal
Depth Mannings N Permissible
Shear Stress
Calculated
Shear Stress
Safety
Factor Remarks Staple
Pattern
C350
Unvegetated
Straight 18.3 cfs 7.83 ft/s 0.61 ft 0.029 3.2 lbs/ft2 3.04 lbs/ft2 1.05 STABLE E
Underlying
Substrate
Straight 18.3 cfs 7.83 ft/s 0.61 ft 0.029 3.49 lbs/ft2 1.99 lbs/ft2 1.75 STABLE E
C350 Reinforced
Vegetation
Straight 18.3 cfs 8.88 ft/s 0.56 ft 0.024 12 lbs/ft2 2.79 lbs/ft2 4.3 STABLE E
Underlying
Substrate
Straight 18.3 cfs 8.88 ft/s 0.56 ft 0.024 3.2 lbs/ft2 1.86 lbs/ft2 1.72 STABLE E
8/5/22, 10:43 AM ECMDS 7.0
https://ecmds.com/project/151501/channel-analysis/220424/show 1/1
North American Green
5401 St. Wendel-Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v7.0
CHANNEL ANALYSIS
> > > TEMPORARY DITCH A1
Name TEMPORARY DITCH A1
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
Phase Reach Discharge Velocity Normal
Depth Mannings N Permissible
Shear Stress
Calculated
Shear Stress
Safety
Factor Remarks Staple
Pattern
S150BN
Unvegetated
Straight 4.19 cfs 4.8 ft/s 0.46 ft 0.033 1.9 lbs/ft2 1.73 lbs/ft2 1.1 STABLE D
Underlying
Substrate
Straight 4.19 cfs 4.8 ft/s 0.46 ft 0.033 2.07 lbs/ft2 1.09 lbs/ft2 1.9 STABLE D
Unreinforced Vegetation
Phase Reach Discharge Velocity Normal
Depth Mannings N Permissible
Shear Stress
Calculated
Shear Stress
Safety
Factor Remarks Staple
Pattern
Unreinforced
Vegetation
Straight 4.19 cfs 3.95 ft/s 0.52 ft 0.043 4 lbs/ft2 1.98 lbs/ft2 2.02 STABLE --
Underlying
Substrate
Straight 4.19 cfs 3.95 ft/s 0.52 ft 0.043 4 lbs/ft2 1.21 lbs/ft2 3.3 STABLE --
8/5/22, 10:46 AM ECMDS 7.0
https://ecmds.com/project/151501/channel-analysis/220408/show 1/1
North American Green
5401 St. Wendel-Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v7.0
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
Phase Reach Discharge Velocity Normal
Depth Mannings N Permissible
Shear Stress
Calculated
Shear Stress
Safety
Factor Remarks Staple
Pattern
Unreinforced
Vegetation
Straight 10.19 cfs 4.16 ft/s 0.71 ft 0.035 4 lbs/ft2 1.16 lbs/ft2 3.46 STABLE --
Underlying
Substrate
Straight 10.19 cfs 4.16 ft/s 0.71 ft 0.035 3.17 lbs/ft2 0.76 lbs/ft2 4.14 STABLE --
S75BN
Phase Reach Discharge Velocity Normal
Depth Mannings N Permissible
Shear Stress
Calculated
Shear Stress
Safety
Factor Remarks Staple
Pattern
S75BN
Unvegetated
Straight 10.19 cfs 4.5 ft/s 0.67 ft 0.031 1.6 lbs/ft2 1.09 lbs/ft2 1.46 STABLE D
Underlying
Substrate
Straight 10.19 cfs 4.5 ft/s 0.67 ft 0.031 1.74 lbs/ft2 0.73 lbs/ft2 2.39 STABLE D
8/25/22, 6:00 PM ECMDS 7.0
RI 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
North American Green
5401 St. Wendel-Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v7.0
Phase
Reach
Discharge
Velocity
Normal
Depth
Mannings N
Permissible
Shear Stress
Calculated
Shear Stress
Safety
Factor
Remarks
Staple
Pattern
S150BN
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
Straight
0.79 cfs
2.64 ft/s
0.21 ft
0.039
1.9 lbs/ft2
0.78 Ibs/ft2
2.44
STABLE
D
https://ecmds.com/project/153137/channel-analysis/230307/show 1/1

8/25/22, 6:09 PM ECMDS 7.0
RI 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
North American Green
5401 St. Wendel-Cynthiana Rd.
Poseyville, Indiana 47633
Tel. [phone]
>Fax [phone]
www.nagreen.com
ECMDS v7.0
Phase
Reach
Discharge
Velocity
Normal
Depth
Mannings N
Permissible
Shear Stress
Calculated
Shear Stress
Safety
Factor
Remarks
Staple
Pattern
SC150BN
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
Straight
Unreinforced Vegetation
11.53 cfs
5.83 ft/s
0.61 ft
0.032
2 lbs/ft2
1.91 Ibs/ft2
1.05
STABLE
D
Phase
Reach
Discharge
Velocity
Normal
Depth
Mannings N
Permissible
Shear Stress
Calculated
Shear Stress
Safety
Factor
Remarks
Staple
Pattern
Unreinforced
Vegetation
Underlying
Substrate
Straight
11.53 cfs 6.29 ft/s 0.58 ft 0.029 4 lbs/ft2 1.81 Ibs/ft2 2.21
STABLE
Straight 11.53 cfs 6.29 ft/s 0.58 ft 0.029 1.28 lbs/ft2 1.25 Ibs/ft2 1.03 STABLE
https://ecmds.com/project/153137/channel-analysis/230310/show 1/1

Channel Report
Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc.Thursday, Aug 25 2022
TD A1 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
Highlighted
Depth (ft) = 0.34
Q (cfs) = 1.500
Area (sqft)= 0.30
Velocity (ft/s)= 4.95
Wetted Perim (ft) = 1.49
Crit Depth, Yc (ft) = 0.46
Top Width (ft)= 1.26
EGL (ft)= 0.72
0 1 2 3
Elev (ft)Section
99.50
100.00
100.50
101.00
101.50
102.00
Reach (ft)
Channel Report
Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc.Thursday, Aug 25 2022
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
Highlighted
Depth (ft) = 0.25
Q (cfs) = 0.790
Area (sqft)= 0.20
Velocity (ft/s)= 4.03
Wetted Perim (ft) = 1.27
Crit Depth, Yc (ft) = 0.33
Top Width (ft)= 1.12
EGL (ft)= 0.50
0 1 2 3
Elev (ft)Section
99.50
100.00
100.50
101.00
101.50
102.00
Reach (ft)

APPENDIX G

Rip-rap Apron Calculations

Appendicex
Outlet
pipe
diameter (Do)
APRON DEPTH IS 1.5 TIMES THE STONE
DIAMETER (1 A" MINIMUM DEPTH)
20
10
tt]PT
[MIN. LENGTH)
0
i
La --+1
=00+La
T.iwater 0.500
i0"
01 p� 60 ---+
tir
.0.‘. 50 , .
40
ifer
i. D �NI►,V' liA!!1I•• •IF II
,l 1r in }m
.r�_, ► ii01 11 r.ri1llii 111111
jtd �� i1i ° I w
i! 1 1
.����>lpppipppH111r11iYYNlItlItl�lYftllgppl!
-��-�"i�®gl�lli�l�■11��11
4
3
2
1
3 5 10 20 50 100 200 500 1000
Discharge (ft3/sec)
Curves may riot be extrapolated.
Figure 8.06a Design of outlet protection protection from a round pipe flowing lull, minimum tailwatercondition {TW < 0.5 diameter)_
STRUCTURE:
DISCHARGE:
PIPE DIA. (D)
Skimmer A
44.92 cfs
24 in
LENGTH:
WIDTH:
d50:
DEPTH;
24.0 ft
26.0 ft
0.9 ft
1.5ft
d5❑ Riprap Size (ft)
0.50 FT
(MIN. d5t]J
Hey. 12/91
8.063

Appendices
Outlet
pipe
diameter (Do)
W = Da + La
La
APRON DEPTH IS 1,5 TIMES THE STONE
DIAMETER Ii8' MINIMUM DEPTH)
20
-- 10
10 FT
IMIN.LENGTH)
0
v=5
30
•fl
cOP 50
40
0 "C 60
!
7
w
..y
..1
10 20 50 100
Discharge (ft3/sec)
80
200
90
.4
0 015111
toil I rf0 FAS S !;',1
500
h
{
1
0
1000
Curves may riot be extrapolated.
Figure 8.06a Design of outlet protection protection from a round pipe flowing full, minimum tailwater condition {TW < 0.5 diameter)_
STRUCTURE:
DISCHARGE:
PIPE DIA. (D)
CO
32.74 cfs
30 in
LENGTH:
WIDTH:
d50:
DEPTH:
16 ft
18.5ft
0.5 ft
1.5 ft
0.50 FT
(MIN,d5o)
Hey. 1219:1

Appendicex
Outlet
pipe
diameter (Do)
APRON DEPTH 15 1.5 TIMES THE STONE
DIAMETER {18" MINIMUM DEPTH)
20
-- 10
ICI Fr
[MIN. LENGTH)
0
3
5
i
La --+1
=lDn+La
T.iwater 0.500
70
60
L��9ir II �
�,�vtn 50 ` .i...
.1
O,
40
80
90
MVP
Ail ION 44
nlnlniRI iiiii!i
i 111
ii11.1Fil
r i 4101:
1.
0
10 20 50 100 200 500 1000
Discharge (ft3/sec)
Curves may riot be extrapolated.
Figure 8.05a Design of outlet protection protection from a round pipe flowing lull, minimum tailwater condition {TW < 0.5 diameter)_
STRUCTURE:
DISCHARGE:
PIPE DIA. (D)
Al
4.19 cis
,A to
LENGTH:
WIDTH:
d50:
DEPTH:
8.0 ft
9.0 ft
0.5 ft
1.5ft
d5o Riprap Size (ft)
0.50 FT
(MIN.d501
Rev. 1219:1

Appendicex
Outlet
pipe
diameter (Do)
W = Da + La
La
APRON DEPTH IS 1.5 TIMES THE STONE
DIAMETER (18" MINIMUM DEPTH)
20
-- 10
IC Fr
MIN. LENGTH)
0
4.0
30
sq
;I
i6‘
p1 p'60
70
80
90
jl
3 5 10 20 50 100 200 500 1000
Discharge (ft3/sec)
Curves may riot be extrapolated.
Figure 8.06a Design of outlet protection protection from a round pipe flowing full, minimum tailwater condition (TW a 0.5 diameter) -
STRUCTURE:
DISCHARGE:
PIPE DIA. (D)
A2
10.19 cfs
24 in
LENGTH:
WIDTH:
d50:
DEPTH:
13.0 ft
15.0 ft
0.5 ft
1.5ft
d5❑ Riprap Size (ft)
0.50 FT
IMIW,d50)
Rev. 1219:1
8.03

Appendicex
Outlet
pipe
diameter (Do)
W = Da + La
La
APRON DEPTH IS 1,5 TIMES THE STONE
DIAMETER Ii8' MINIMUM DEPTH)
3Q
20
- - 10
IC FT
[MIN. LENGTH)
0
iQ�
fl� t' 60
�,�1v� 50
40
0
80
90
1
10 20 50 100 200 500 1000
Discharge (ft3/sec)
Curves may riot be extrapolated.
Figure 8.06a Design of outlet protection protection from a round pipe flowing full, minimum tailwater condition (TW < 0.5 diameter)
STRUCTURE:
DISCHARGE:
PIPE DIA. (D)
AO
65.74 cfs
36 in
LENGTH:
WIDTH:
d50:
DEPTH:
23.0 ft
26.0 ft
0.6 ft
1.5ft
d5❑ Riprap Size RI)
0.50 FT
(MIN. d50)
Rev. 1219:1

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
Basin Characteristics
Parameter
Code Parameter Description
0 Collapse All
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
https://streamstats.usgs.gov/ss/ 1/3

8/9/22, 9:38 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 0.31 square 0.04 41
miles
LC11IMP Percent_Impervious_NLCD2011 3.9 percent 2 54.6
Urban Peak -Flow Statistics Flow Report [Region 2 Urban Blue Ridge FS007-00]
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.
https://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
https://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
0 Collapse All
Value Unit
0.0997 square
miles
LC11IMP Average percentage of impervious area determined from 1.3 percent
NLCD 2011 impervious dataset
Urban Peak -Flow Statistics
https://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
https://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
https://streamstats.usgs.gov/ss/ 3/3

APPENDIX I

Storm Drainage Calculations
D Civil
design
Concepts, PA
STORM DRAIN CALCULATIONS
(25 YEAR EVENT)
Mitchell County Middle School
CDC Project No.: 12208
PIPE
STRUCTURE
DRAINAGE
PIPE NAME
INVERT
UPSTREAM
INVERT
DOWNSTREAM
PIPE SIZE
PIPE LENGTH
SLOPE
MANNING'S
ROUGHNESS
STRUCTURE
NUMBER
GRATE/TOP
ELEVATION
HEAD WATER
CATCHMENT
AREA
INLET Tc
WEIGHTED
RUNOFF
RAINFALL
INTENSITY
LOCAL FLOW
TOTAL FLOW
VELOCITY
CAPACITY FULL
7/8 CAPACITY
FULL
(FT)
(FT)
(IN)
(FT)
(%)
"N"
(FT)
(FT)
(AC)
(MIN)
"C"
(IN/HR)
(CFS)
(CFS)
(FT/SEC)
(CFS)
(CFS)
A1-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
El
2749.41
0.94
0.17
5.0
0.95
7.98
1.29
2.43
1.98
22.17
21.99
E2-E1
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
B2-B1
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
B3-B2
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-A1
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-A11
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
Cl
2740.45
4.67
0.00
0.0
0.00
0.00
0.00
42.81
11.17
48.59
48.27
C2-C1
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
J1
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

Rainfall not specifiedStream Culvert
Printed 8/30/2022Prepared by Civil Design Concepts
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC
Summary for Reach 1R: Culvert Z1
[52] Hint: Inlet/Outlet conditions not evaluated
[55] Hint: Peak inflow is 138% of Manning's capacity
[76] Warning: Detained 83.871 af (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 '/' (101 Elevation Intervals)
Inlet Invert= 2,731.10', Outlet Invert= 2,730.50'

APPENDIX J

Wet Pond Forebay and Permanent Pool Volume Calculations

3PF
Wet Pond 'A' Forebay
Routing Diagram for 12208 Stormwater Analysis
Prepared by Civil Design Concepts, Printed 8/16/2022
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC
Subcat Reach Pond Link
MITCHELL COUNTY MIDDLE SCHOOL
Type II 24-hr 50-yr Rainfall=7.94"12208 Stormwater Analysis
Printed 8/16/2022Prepared by Civil Design Concepts
Page 2HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC
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) Listed 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
Routing Diagram for 12208 Stormwater Analysis
Prepared by Civil Design Concepts, Printed 8/16/2022
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC
Subcat Reach Pond Link
MITCHELL COUNTY MIDDLE SCHOOL
Type II 24-hr 50-yr Rainfall=7.94"12208 Stormwater Analysis
Printed 8/16/2022Prepared by Civil Design Concepts
Page 2HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC
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) Listed 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
Type II 24-hr 1-in. Rainfall=1.00"12208 Stormwater Analysis
Printed 8/9/2022Prepared by Civil Design Concepts
Page 1HydroCAD® 10.20-2f s/n 04679 © 2022 HydroCAD Software Solutions LLC
Hydrograph for Pond 3P: Proposed Wet Pond 'A'
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Primary
(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
Type II 24-hr 1-in. Rainfall=1.00"12208 Stormwater Analysis
Printed 8/9/2022Prepared by Civil Design Concepts
Page 2HydroCAD® 10.20-2f s/n 04679 © 2022 HydroCAD Software Solutions LLC
Hydrograph for Pond 3P: Proposed Wet Pond 'A' (continued)
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Primary
(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
Type II 24-hr 1-in. Rainfall=1.00"12208 Stormwater Analysis
Printed 8/9/2022Prepared by Civil Design Concepts
Page 3HydroCAD® 10.20-2f s/n 04679 © 2022 HydroCAD Software Solutions LLC
Hydrograph for Pond 3P: Proposed Wet Pond 'A' (continued)
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Primary
(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
Type II 24-hr 1-in. Rainfall=1.00"12208 Stormwater Analysis
Printed 8/9/2022Prepared by Civil Design Concepts
Page 4HydroCAD® 10.20-2f s/n 04679 © 2022 HydroCAD Software Solutions LLC
Hydrograph for Pond 3P: Proposed Wet Pond 'A' (continued)
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Primary
(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
Type II 24-hr 1-in. Rainfall=1.00"12208 Stormwater Analysis
Printed 8/9/2022Prepared by Civil Design Concepts
Page 5HydroCAD® 10.20-2f s/n 04679 © 2022 HydroCAD Software Solutions LLC
Hydrograph for Pond 3P: Proposed Wet Pond 'A' (continued)
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Primary
(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
Type II 24-hr 1-in. Rainfall=1.00"12208 Stormwater Analysis
Printed 8/9/2022Prepared by Civil Design Concepts
Page 6HydroCAD® 10.20-2f s/n 04679 © 2022 HydroCAD Software Solutions LLC
Hydrograph for Pond 3P: Proposed Wet Pond 'A' (continued)
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Primary
(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
Type II 24-hr 1-in. Rainfall=1.00"12208 Stormwater Analysis
Printed 8/9/2022Prepared by Civil Design Concepts
Page 7HydroCAD® 10.20-2f s/n 04679 © 2022 HydroCAD Software Solutions LLC
Hydrograph for Pond 3P: Proposed Wet Pond 'A' (continued)
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Primary
(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
Type II 24-hr 1-in. Rainfall=1.00"12208 Stormwater Analysis
Printed 8/9/2022Prepared by Civil Design Concepts
Page 8HydroCAD® 10.20-2f s/n 04679 © 2022 HydroCAD Software Solutions LLC
Hydrograph for Pond 3P: Proposed Wet Pond 'A' (continued)
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Primary
(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
1S
Pre Development
2S
Post Development
3P
Proposed Wet Pond 'A'
Routing Diagram for 12208 Stormwater Analysis
Prepared by Civil Design Concepts, Printed 8/11/2022
HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC
Subcat Reach Pond Link
MITCHELL COUNTY MIDDLE SCHOOL
Type II 24-hr 1-yr Rainfall=3.25"12208 Stormwater Analysis
Printed 8/11/2022Prepared by Civil Design Concepts
Page 2HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC
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/grassland/range, 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
9.9 410 Total
Subcatchment 1S: Pre Development
Runoff
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420
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10
9
8
7
6
5
4
3
2
1
0
Type II 24-hr
1-yr Rainfall=3.25"
Runoff Area=329,211 sf
Runoff Volume=23,520 cf
Runoff Depth=0.86"
Flow Length=410'
Slope=0.1100 '/'
Tc=9.9 min
CN=70
8.96 cfs
MITCHELL COUNTY MIDDLE SCHOOL
Type II 24-hr 1-yr Rainfall=3.25"12208 Stormwater Analysis
Printed 8/11/2022Prepared by Civil Design Concepts
Page 3HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC
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
Runoff
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420
Fl
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(
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26
24
22
20
18
16
14
12
10
8
6
4
2
0
Type II 24-hr
1-yr Rainfall=3.25"
Runoff Area=329,211 sf
Runoff Volume=53,748 cf
Runoff Depth=1.96"
Tc=5.0 min
CN=87
24.02 cfs
MITCHELL COUNTY MIDDLE SCHOOL
Type II 24-hr 1-yr Rainfall=3.25"12208 Stormwater Analysis
Printed 8/11/2022Prepared by Civil Design Concepts
Page 4HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD 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 )
Volume Invert Avail.Storage Storage Description
#1 2,724.99' 66,384 cf Custom Stage Data (Irregular) Listed 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)
1=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
Type II 24-hr 1-yr Rainfall=3.25"12208 Stormwater Analysis
Printed 8/11/2022Prepared by Civil Design Concepts
Page 5HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC
Pond 3P: Proposed Wet Pond 'A'
Inflow
Primary
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420
Fl
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(
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26
24
22
20
18
16
14
12
10
8
6
4
2
0
Inflow Area=329,211 sf
Peak Elev=2,726.76'
Storage=26,091 cf
24.02 cfs
4.53 cfs

APPENDIX M

10-Year Storm Event
HydroCAD Output Report
MITCHELL COUNTY MIDDLE SCHOOL
Type II 24-hr 10-yr Rainfall=5.80"12208 Stormwater Analysis
Printed 8/11/2022Prepared by Civil Design Concepts
Page 6HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC
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/grassland/range, 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
9.9 410 Total
Subcatchment 1S: Pre Development
Runoff
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420
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(
c
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s
)
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Type II 24-hr
10-yr Rainfall=5.80"
Runoff Area=329,211 sf
Runoff Volume=72,630 cf
Runoff Depth=2.65"
Flow Length=410'
Slope=0.1100 '/'
Tc=9.9 min
CN=70
29.67 cfs
MITCHELL COUNTY MIDDLE SCHOOL
Type II 24-hr 10-yr Rainfall=5.80"12208 Stormwater Analysis
Printed 8/11/2022Prepared by Civil Design Concepts
Page 7HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC
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
Runoff
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420
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55
50
45
40
35
30
25
20
15
10
5
0
Type II 24-hr
10-yr Rainfall=5.80"
Runoff Area=329,211 sf
Runoff Volume=118,683 cf
Runoff Depth=4.33"
Tc=5.0 min
CN=87
51.23 cfs
MITCHELL COUNTY MIDDLE SCHOOL
Type II 24-hr 10-yr Rainfall=5.80"12208 Stormwater Analysis
Printed 8/11/2022Prepared by Civil Design Concepts
Page 8HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD 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 )
Volume Invert Avail.Storage Storage Description
#1 2,724.99' 66,384 cf Custom Stage Data (Irregular) Listed 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)
1=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
Type II 24-hr 10-yr Rainfall=5.80"12208 Stormwater Analysis
Printed 8/11/2022Prepared by Civil Design Concepts
Page 9HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC
Pond 3P: Proposed Wet Pond 'A'
Inflow
Primary
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420
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(
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55
50
45
40
35
30
25
20
15
10
5
0
Inflow Area=329,211 sf
Peak Elev=2,727.45'
Storage=37,733 cf
51.23 cfs
43.29 cfs

APPENDIX N

50-Year Storm Event
HydroCAD Output Report

MITCHELL COUNTY MIDDLE SCHOOL
Type II 24-hr 50-yr Rainfall=7.94"12208 Stormwater Analysis
Printed 8/11/2022Prepared by Civil Design Concepts
Page 10HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC
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/grassland/range, 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
9.9 410 Total
Subcatchment 1S: Pre Development
Runoff
Hydrograph
Time (hours)
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Type II 24-hr
50-yr Rainfall=7.94"
Runoff Area=329,211 sf
Runoff Volume=121,061 cf
Runoff Depth=4.41"
Flow Length=410'
Slope=0.1100 '/'
Tc=9.9 min
CN=70
49.46 cfs
MITCHELL COUNTY MIDDLE SCHOOL
Type II 24-hr 50-yr Rainfall=7.94"12208 Stormwater Analysis
Printed 8/11/2022Prepared by Civil Design Concepts
Page 11HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC
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
Runoff
Hydrograph
Time (hours)
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Type II 24-hr
50-yr Rainfall=7.94"
Runoff Area=329,211 sf
Runoff Volume=175,341 cf
Runoff Depth=6.39"
Tc=5.0 min
CN=87
73.98 cfs
MITCHELL COUNTY MIDDLE SCHOOL
Type II 24-hr 50-yr Rainfall=7.94"12208 Stormwater Analysis
Printed 8/11/2022Prepared by Civil Design Concepts
Page 12HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC
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) Listed 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)
1=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
Type II 24-hr 50-yr Rainfall=7.94"12208 Stormwater Analysis
Printed 8/11/2022Prepared by Civil Design Concepts
Page 13HydroCAD® 10.00-12 s/n 04679 © 2014 HydroCAD Software Solutions LLC
Pond 3P: Proposed Wet Pond 'A'
Inflow
Primary
Hydrograph
Time (hours)
605856545250484644424038363432302826242220181614121086420
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Inflow Area=329,211 sf
Peak Elev=2,727.71'
Storage=42,134 cf
73.98 cfs
65.74 cfs