SW3231103_Stormwater Report_20231121

STORMWATER REPORT
Prepared For:
JCH NC, LLC
HERITAGE AT MARVIN
SINGLE FAMILY SUBDIVISION
MARVIN, NORTH CAROLINA
Prepared By:
CIVIL & ENVIRONMENTAL CONSULTANTS, INC.
CHARLOTTE, NORTH CAROLINA
CEC Project 326-256
NOVEMBER 2023
NORTH CAROLINA •��///Y,
SEAL
BOARD OF EXAMINERS = 043168
FOR ENGINEERS AND ' i
%9d�0'FHGINEER*..c• :\
SURVEYORS .. �G .��
LICENSE NO.C-3035 ////,//1� nG``\`\\` 11/16/23
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Civil & Environmental Consultants, Inc.
Charlotte 3701 Arco Corporate Drive,Suite 400 I Charlotte, NC 28273 I p:980-237-0373 f:980-237-0372 I www.cecinc.com

TABLE OF CONTENTS
Page
1.0 CONSTRUCTION NARRATIVE 1
1.1 PROJECT DESCRIPTION 1
1.2 SITE DESCRIPTION 1
1.3 ADJACENT PROPERTIES 1
1.4 SOILS 2
2.0 STORMWATER CONSTRUCTION SEQUENCE 3
3.0 PERMANENT STORMWATER MEASURES 4
3.1 PROPOSED STORMWATER SYSTEM 4
3.2 STORMWATER CALCULATIONS 5
TABLES
Table 1 —Soil Properties
Table 2—Summary of Pre/Post Peak Discharges & Max Elevations
APPENDICES
Appendix A— Stormwater Calculations Supplemental Documents
Appendix B—Permanent Stormwater Calculations
Heritage at Marvin
Civil & Environmental Consultants, Inc. Stormwater Report

1.0 CONSTRUCTION NARRATIVE
1..1 PROJECT DESCRIPTION
This project consists of the construction of a single-family residential development along with
associated roadways, driveways, sidewalks, stormwater management facility, and other associated
features on a 46-acre site.
1.2 SITE DESCRIPTION
The existing site is located on New Town Road in Union County,North Carolina. The site is densely
wooded in its current condition. A jurisdictional wetland is located within the property boundary
south of the project site. Slopes range from 0-8% on majority of the site. Steep slopes up to 40%
are found on small portions of the site.
The proposed site will have 2 main entrances at latitude N034°59'45.78" longitude W080°49'26.43"
and latitude N034°59'41.10" longitude W080°49'38.86" along New Town Road. The site will be
graded to construct single family house pads, paved driveways, erosion control measures, and
stormwater collection pipes. A topographic map (Figure 1) in the appendix shows the general area
of the project site and surrounding features.
1.3 ADJACENT PROPERTIES
The project site is bounded on the east,west and south by residential areas,and the New Town Road
corridor to the north.
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Stormwater Report

1.4 SOILS
The soils located within the disturbed limit are described in the table below:
TABLE 1 - SOIL PROPERTIES
Hydrologic
Map Unit Symbol Map Unit Name Soil Group
Rating
ApB Appling Sandy Loam, 2 to 8 percent slopes B
CoA Colfax sandy loam, 0 to 3 percent slopes C/D
HeB Helena fine sandy loam, 2 to 8 percent slopes D
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2.0 STORMWATER CONSTRUCTION SEQUENCE
1. Once grading is complete and the entire site has been stabilized for the Development the
Erosion Control Sediment Basin #1 & Sediment Basin #2 may be converted to SCM Wet
Ponds.
2. Proposed Wet Pond#1 &Wet Pond#2 will treat the storm drainage from all impervious areas
on the site including roof drainage and asphalt/concrete pavement.
3. Proposed Wet Pond #1 & Wet Pond #2 have been sized to receive storm drainage from the
proposed roof drainage, roadways, driveways and sidewalks with a proposed drainage area of
18.99 acres and an impervious area of 5.96 acres(34%of area)for Wet Pond#1 and a proposed
drainage area of 22.07 acres and an impervious area of 6.88 acres (35% of area) for Wet Pond
#2, see attached Drainage Area map Figure HYD-3 in Appendix B.
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3.0 PERMANENT STORMWATER MEASURES
3.1 PROPOSED STORMWATER SYSTEM
The stormwater runoff for the project primarily originates from roadways of the development
driveways, building roofs, sidewalks, and on-site grassed areas. This project has an
impervious area totaling 14.09 acres for both wetponds. See Figure HYD-3 in Appendix B
for the drainage areas into the proposed stormwater management facilities. Stormwater on the
site is directed to any one of a number of drainage structures, including but not limited to
grate inlets, yard inlets and curb inlets. Once the stormwater has entered the drainage system
through the structures, it is directed by gravity flow through the stormwater drainage system
to Proposed Wet Pond #1 & Wet Pond #2.
For the Proposed Wet Pond#1, Hydrology analysis using TR-55 Tables provided a curve number
of 62.5 for pre-developed area, and a curve number of 73.5 for post-developed area. For the
Proposed Wet Pond#2, Hydrology analysis using TR-55 Tables provided a curve number of 61.4
for pre-developed area, and a curve number of 72.7 for post-developed area. Rainfall depth data
from NOAA Atlas 14,Volume 2,Version 3. The analysis demonstrates that pre-development peak
discharge will decrease for the 10-year 24-hour storm event at the Point of Interest (POI) for(see
drainage area maps attached and Table 2 below).
TABLE 2 - SUMMARY OF PRE/POST PEAK DISCHARGES & MAX ELEVATIONS
ANALYSIS POINT-SITE OUTFALL
Storm Event Pre-Development (cfs) Post-Development(cfs) Max Elevation Max Elevation
SCM#1 (ft) SCM#2 (ft)
1-YEAR 5.29 0.48 646.82 646.29
2-YEAR 11.18 0.58 647.68 646.95
10-YEAR 34.29 9.53 648.22 648.10
25-YEAR 51.26 42.73 648.63 648.26
50-YEAR 65.93 71.73 649.13 648.52
100-YEAR 81.45 123.02 649.59 649.92
The post-developed discharge from the 10-year 24-hour storm event meets NCDEQ (North
Carolina Department of Environmental Quality) requirements. The site outfalls to an existing low
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Stormwater Report

area on site where a jurisdictional wetland is located. Riprap dissipaters in conjunction with
matting and riprap-lined channels are used to reduce flow velocities. Furthermore, after the
stormwater runoff has exited the riprap dissipaters, it will flow through undisturbed existing
vegetated areas, further decreasing the velocity before entering surface waters adjacent to the site.
3.2 STORMWATER CALCULATIONS
Stormwater calculations were performed using the rational method to determine the peak flow
through any one drainage structure. These flows were added together,proceeding downstream in
the system to ensure that each subsequent pipe was capable of handling the peak flows. The 10-
year 24-hour storm event was used with a 5-minute time-of-concentration to yield an intensity (i)
value for the storm drainage piping system.
Wet Pond calculations were performed using Hydrographs while treating the Pt inch of rainfall
with the outlet structure controlling the 10-year 24-hour storm events, resulting in the flows from
post-development being less than the pre-development flows. Proposed Wet Pond #1 has been
sized to be capable of handling the 50-year storm event with a max elevation of 649.13 with a peak
flow of 46.58 cfs before activating the emergency overflow weir. The emergency overflow weir
is capable of handling the 100-year storm event with a max elevation of 649.59,which is 0.41 feet
from the top of berm with a peak flow of 70.22 cfs. Proposed Wet Pond #2 has been sized to be
capable of handling the 50-year storm event with a max elevation of 648.52 with a peak flow of
25.15 cfs before activating the emergency overflow weir. The emergency overflow weir is capable
of handling the 100-year storm event with a max elevation of 648.92, which is 1.08 feet from the
top of berm with a peak flow of 52.80 cfs.
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Stormwater Report

Proposed Wet Pond #1
Pre-Developed Drainage Area 1 Year 24 Hour Volume: 26,759 cuft
Post-Developed Drainage Area 1 Year 24 Hour Volume: 54,630 cuft
Difference Between Pre-Developed and Post-Developed Volume: 54,630 - 26,759 =27,871 cuft
Pond Storage Elevation: 646.18
Elevation(ft) Acc Vol.(cf)
645.00 0 Permanent Pool
645.50 10,544
646.00 23,052
646.18 27,871
646.50 36,315
647.00 50,116
647.50 64,460
648.00 79,356 Top of Riser
648.50 94,810
649.00 110,830
649.50 127,422
650.00 144,593 Top of Pond
Proposed Wet Pond #2
Pre-Developed Drainage Area 1 Year 24 Hour Volume: 28,462 cuft
Post-Developed Drainage Area 1 Year 24 Hour Volume: 60,544 cuft
Difference Between Pre-Developed and Post-Developed Volume: 60,544-28,462 = 32,082 cuft
Pond Storage Elevation: 645.62
Elevation(ft) Acc Vol.(cf)
645.00 0 Permanent Pool
645.50 16,977
645.62 32,082
646.00 36,732
646.50 57,416
647.00 78,730
647.50 100,681
648.00 123,276 Top of Riser
648.50 146,524
649.00 170,430
649.50 195,001
650.00 220,245 Top of Dam
With this project being High Density as proposed, to meet the requirements of Water Quality and
Peak Control parameters, Wet Pond SCM's were the preferred method of treatment. Due to the
poor soil conditions and retention of as much existing vegetation and natural area as possible, the
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Stormwater Report

promotion of infiltration was not able to be obtained with our approach to meeting the Goose Creek
Watershed rules. However,we are able to provide more volume control with the use of Wet Pond
style SCM's.
Civil & Environmental Consultants,Inc. -7- Heritage at Marvin
Stormwater Report

APPENDIX A
STORMWATER CALCULATIONS
SUPPLEMENTAL DOCUMENTS

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1. U.S.G.S. 7.5' TOPOGRAPHIC MAP, CATWABA, SC I I
a QUADRANGLE, DATED: 2020. 0 2000 4000
3
o ,-,=,-rE M HERITAGE AT MARVIN
SINGLE-FAMILY SUBDIVISION
N Civil & Environmental Consultants, Inc. JONES HOMES USA
43 3701 Arco Corporate Drive-Suite 400-Charlotte, NC 28273 MARVIN, NORTH CAROLINA
tn Ph:980.237.0373-Fax:[phone]
0 TOPOGRAPHIC MAP
o www.cecinc.com
R, DRAWN BY: ERR CHECKED BY: ATB APPROVED BY: MLG FIGURE NO.:
DATE: JULY 2023 DWG SCALE: 1"=2000' PROJECT NO: 326-256 1

SOIL DATA

3 Soil Map—Union County,North Carolina 3
(property boundry)
ol
515560 515650 515740 515830 515920 516010 516100 516190 516280 516370 516460
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34°59'28"N -- 34°59'28"N
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3 3
TA Map Scale:1:4,200 if printed on A landscape(11"x 8.5")sheet. a
v Meters v
m N 0 50 100 200 X0 $
Feet
A
0 200 400 m 800 1200
Map projection:Web Mercabar Coer coordinates:WC584 Edge tics:UTM Zone 17N WGS84
USDA Natural Resources Web Soil Survey 2/7/2023
Conservation Service National Cooperative Soil Survey Page 1 of 3

Soil Map—Union County,North Carolina
(property boundry)
MAP LEGEND MAP INFORMATION
Area of Interest(AOI) Spoil Area The soil surveys that comprise your AOI were mapped at
Area of Interest(AOI) 1:24,000.
Q Stony Spot
Soils Very Stony Spot Warning:Soil Map may not be valid at this scale.
0 Soil Map Unit Polygons
Wet Spot Enlargement of maps beyond the scale of mapping can cause
.�� Soil Map Unit Lines misunderstanding of the detail of mapping and accuracy of soil
Other line placement.The maps do not show the small areas of
p Soil Map Unit Points contrasting soils that could have been shown at a more detailed
Special Line Features
Special Point Features scale.
(o, Blowout Water Features
Streams and Canals Please rely on the bar scale on each map sheet for map
cs Borrow Pit measurements.
Transportation
I Clay Spot Rails Source of Map: Natural Resources Conservation Service
0 Closed Depression Web Soil Survey URL:
ti Interstate Highways Coordinate System: Web Mercator(EPSG:3857)
X Gravel Pit US Routes
04,00 Maps from the Web Soil Survey are based on the Web Mercator
,. Gravelly Spot Major Roads projection,which preserves direction and shape but distorts
distance and area.A projection that preserves area,such as the
0 Landfill Local Roads Albers equal-area conic projection,should be used if more
Lava Flow accurate calculations of distance or area are required.
Background
46 Marsh or swamp Aerial Photography This product is generated from the USDA-NRCS certified data as
of the version date(s)listed below.
iRk Mine or Quarry
Soil Survey Area: Union County, North Carolina
O Miscellaneous Water Survey Area Data: Version 23,Sep 12,2022
Q Perennial Water Soil map units are labeled(as space allows)for map scales
v Rock Outcrop 1:50,000 or larger.
▪ Saline Spot Date(s)aerial images were photographed: Mar 13,2022—May
9,2022
Sandy Spot
The orthophoto or other base map on which the soil lines were
Severely Eroded Spot compiled and digitized probably differs from the background
imagery displayed on these maps.As a result,some minor
• Sinkhole shifting of map unit boundaries may be evident.
3) Slide or Slip
oa Sodic Spot
i\ Natural Resources Web Soil Survey 2/7/2023
001. Conservation Service National Cooperative Soil Survey Page 2 of 3

Soil Map—Union County, North Carolina property boundry
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
ApB Appling sandy loam,2 to 8 28.1 61.4%
percent slopes
CoA Colfax sandy loam,0 to 3 12.5 27.3%
percent slopes
HeB Helena fine sandy loam,2 to 8 5.1 11.3%
percent slopes
Totals for Area of Interest 45.7 100.0%
USDA Natural Resources Web Soil Survey 2/7/2023
Conservation Service National Cooperative Soil Survey Page 3 of 3

a Hydrologic Soil Group—Union County,North Carolina
(property boundry)
in
515560 515650 515740 515830 515920 516010 516100 516190 516280 516370 516460
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515560 515650 515740 515830 515920 516010 516100 516193 516280 516370 516460
3 3
Map Scale:1:4,200 if printed on A landscape(11"x 8.5")sheet. a
v Meters v
a N 0 50 100 ao 300 $
Feet
A
0 200 400 m 800 1200
Map projection:Web Mercator Coer coordinates:WC584 Edge tics:UTM Zone 17N WGS84
USDA Natural Resources Web Soil Survey 2/7/2023
Conservation Service National Cooperative Soil Survey Page 1 of 4

Hydrologic Soil Group—Union County,North Carolina
(property boundry)
MAP LEGEND MAP INFORMATION
Area of Interest(AOI) p c The soil surveys that comprise your AOI were mapped at
Area of Interest(AOI) 1:24,000.
0 C/D
Soils • D Warning:Soil Map may not be valid at this scale.
Soil Rating Polygons
l A p Not rated or not available Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
n A/D Water Features line placement.The maps do not show the small areas of
Streams and Canals contrasting soils that could have been shown at a more detailed
n B scale.
Transportation
Q B/D
r4-1. Rails Please rely on the bar scale on each map sheet for map
n C measurements.
ti Interstate Highways
C/D US Routes Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
0 D Major Roads Coordinate System: Web Mercator(EPSG:3857)
n Not rated or not available Local Roads
Maps from the Web Soil Survey are based on the Web Mercator
Soil Rating Lines Background projection,which preserves direction and shape but distorts
• • A distance and area.A projection that preserves area,such as the
1111 Aerial Photography Albers equal-area conic projection,should be used if more
• • A/D accurate calculations of distance or area are required.
^r B This product is generated from the USDA-NRCS certified data as
.v B/D of the version date(s)listed below.
• r C Soil Survey Area: Union County, North Carolina
Survey Area Data: Version 23,Sep 12,2022
• • CID
Soil map units are labeled(as space allows)for map scales
• • D 1:50,000 or larger.
• w Not rated or not available Date(s)aerial images were photographed: Mar 13,2022—May
Soil Rating Points 9,2022
p A The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
O A/D imagery displayed on these maps.As a result,some minor
• B shifting of map unit boundaries may be evident.
• B/D
USDA Natural Resources Web Soil Survey 2/7/2023
Conservation Service National Cooperative Soil Survey Page 2 of 4

Hydrologic Soil Group—Union County, North Carolina property boundry
Hydrologic Soil Group
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
ApB Appling sandy loam,2 to B 28.1 61.4%
8 percent slopes
CoA Colfax sandy loam,0 to C/D 12.5 27.3%
3 percent slopes
HeB Helena fine sandy loam, D 5.1 11.3%
2 to 8 percent slopes
Totals for Area of Interest 45.7 100.0%
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive
precipitation from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential)when
thoroughly wet. These consist mainly of deep, well drained to excessively
drained sands or gravelly sands. These soils have a high rate of water
transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well
drained soils that have moderately fine texture to moderately coarse texture.
These soils have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of
water transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential)when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay
layer at or near the surface, and soils that are shallow over nearly impervious
material. These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in
their natural condition are in group D are assigned to dual classes.
USDA Natural Resources Web Soil Survey 2/7/2023
Conservation Service National Cooperative Soil Survey Page 3 of 4

Hydrologic Soil Group—Union County, North Carolina property boundry
Rating Options
Aggregation Method: Dominant Condition
Aggregation is the process by which a set of component attribute values is
reduced to a single value that represents the map unit as a whole.
A map unit is typically composed of one or more "components". A component is
either some type of soil or some nonsoil entity, e.g., rock outcrop. For the
attribute being aggregated, the first step of the aggregation process is to derive
one attribute value for each of a map unit's components. From this set of
component attributes, the next step of the aggregation process derives a single
value that represents the map unit as a whole. Once a single value for each map
unit is derived, a thematic map for soil map units can be rendered. Aggregation
must be done because, on any soil map, map units are delineated but
components are not.
For each of a map unit's components, a corresponding percent composition is
recorded. A percent composition of 60 indicates that the corresponding
component typically makes up approximately 60% of the map unit. Percent
composition is a critical factor in some, but not all, aggregation methods.
The aggregation method "Dominant Condition"first groups like attribute values
for the components in a map unit. For each group, percent composition is set to
the sum of the percent composition of all components participating in that group.
These groups now represent"conditions" rather than components. The attribute
value associated with the group with the highest cumulative percent composition
is returned. If more than one group shares the highest cumulative percent
composition, the corresponding "tie-break" rule determines which value should
be returned. The "tie-break" rule indicates whether the lower or higher group
value should be returned in the case of a percent composition tie. The result
returned by this aggregation method represents the dominant condition
throughout the map unit only when no tie has occurred.
Component Percent Cutoff.None Specified
Components whose percent composition is below the cutoff value will not be
considered. If no cutoff value is specified, all components in the database will be
considered. The data for some contrasting soils of minor extent may not be in the
database, and therefore are not considered.
Tie-break Rule: Higher
The tie-break rule indicates which value should be selected from a set of multiple
candidate values, or which value should be selected in the event of a percent
composition tie.
USDA Natural Resources Web Soil Survey 2/7/2023
Conservation Service National Cooperative Soil Survey Page 4 of 4

RAINFALL DATA

1/16/23, 12:37 PM Precipitation Frequency Data Server
NOAA Atlas 14,Volume 2,Version 3
Su:a Location name: Marvin, North Carolina,USA* ifs.' ''N
Latitude: 34.995°, Longitude: -80.824° norm
Elevation:671.72 ft**
��+` *source:ESRI Maps .
100
�`$`� **source:USGS �,"""`�
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M.Bonnin,D.Martin,B.Lin,T.Parzybok,M.Yekta,and D.Riley
NOAA,National Weather Service,Silver Spring,Maryland
PF tabular I PF graphical I Maps & aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1
Average recurrence interval(years)
Duration 1 2 5 _ 10 25 50 100 - 200 500 1000
5-min 0.416 0.491 0.570 0.628 0.695 0.740 0.783 0.821 0.864 0.894
(0.384-0.452) (0.452-0.534) (0.524-0.620) (0.576-0.681) (0.634-0.752) (0.673-0.802) (0.708-0.847) (0.738-0.889) (0.770-0.938) (0.791-0.973)
10-min 0.665 0.785 0.913 1.00 1.11 1.18 1.24 1.30 1.37 1.41
(0.613-0.721) (0.722-0.855) (0.838-0.993) (0.921-1.09) (1.01-1.20) (1.07-1.28) (1.12-1.35) (1.17-1.41) (1.22-1.48) (1.25-1.53)
15-min 0.831 0.987 1.16 1.27 1.40 1.49 1.57 1.64 1.72 1.77
(0.766-0.901) (0.908-1.07)_ (1.06-1.26) (1.16-1.38) (1.28-1.52) (1.36-1.62) (1.42-1.70) (1.48-1.78) (1.53-1.87) (1.56-1.92)
30-min 1.14 1.36 1.64 1.84 2.08 2.25 2.41 2.56 2.74 2.86
(1.05-1.24) (1.25-1.48) (1.51-1.79) (1.69-2.00) (1.90-2.25) (2.04-2.44) (2.18-2.61) (2.30-2.77) 1 (2.44-2.97) (2.53-3.11)
60-min 1.42 1.71 2.10 2.40 2.77 3.05 3.32 3.58 3.93 4.18
(1.31-1.54) (1.57-1.86) (1.93-2.29) (2.20-2.60)J (2.53-3.00) I (2.77-3.30) (3.00-3.59) (3.22-3.88) (3.50-4.26) (3.70-4.55)
2-hr 1.64 1.99 2.46 2.82 3.30 3.66 4.02 4.38 4.86 5.23
(1.51-1.80) (1.82-2.18) (2.25-2.70) (2.57-3.09) (2.99-3.60) (3.30-3.99) (3.61-4.38) (3.91-4.78) (4.29-5.30) (4.58-5.71)
3-hr 1.75 2.11 2.62 3.03 3.58 4.01 4.45 4.91 5.54 6.04
(1.60-1.92) (1.93-2.32) (2.40-2.88) (2.76-3.32) i (3.24-3.92) (3.61-4.38) (3.98-4.86) (4.36-5.36) (4.85-6.05) (5.23-6.60)
6-hr 2.10 2.53 3.16 3.65 4.33 1 4.87 5.43 6.00 6.81 7.45
(1.93-2.31) (2.32-2.78) (2.89-3.46) (3.33-4.00) , (3.92-4.72) I (4.39-5.30) (4.85-5.91) (5.32-6.53) (5.95-7.40) I (6.44-8.10)
12-hr 2.48 3.00 3.76 4.37 5.21 5.90 6.62 7.38 8.45 9.32
(2.28-2.72) (2.75-3.30) (3.44-4.12) (3.98-4.78) (4.72-5.69) (5.31-6.43) (5.90-7.20) (6.50-8.02) (7.33-9.18) (7.98-10.1)
24-hr 2.94 3.54 4.45 5.17 6.15 6.94 1 7.76 8.61 9.78 10.7
(2.72-3.17) (3.29-3.84)_ (4.12-4.81) (4.78-5.59) (5.67-6.65) (6.38-7.50) (7.11-8.38) (7.85-9.31) (8.87-10.6) (9.68-11.6)
2-day 3.46 4.17 5.20 6.01 7.13 8.03 8.94 9.89 11.2 12.3
(3.21-3.75) (3.87-4.52) I (4.82-5.63) (5.56-6.51) L(6.57-7.71) (7.37-8.68) (8.18-9.69) I (9.02-10.7) (10.2-12.2) (11.1-13.3)
3-day 3.67 4.41 5.47 6.31 7.47 8.40 9.35 10.3 11.7 12.8
(3.41-3.97) (4.10-4.77) (5.08-5.92) (5.84-6.82) (6.89-8.07) (7.72-9.07) (8.57-10.1) (9.44-11.2) (10.6-12.7) (11.6-13.9)
4-day 3.88 4.66 5.75 6.62 7.81 8.77 9.75 10.8 12.2 13.3
(3.61-4.19) (4.33-5.02) (5.34-6.20) (6.12-7.13) (7.21-8.43) (8.07-9.47) (8.95-10.5) (9.85-11.6) (11.1-13.2) (12.1-14.4)
7-day 4.50 5.37 6.54 7.48 8.77 9.80 10.9 12.0 13.5 14.7
(4.21-4.82) (5.02-5.75) (6.11-7.01) (6.98-8.01) (8.15-9.40) (9.09-10.5) (10.0-11.6) (11.0-12.8) (12.4-14.5) (13.4-15.8)
10-day 5.14 6.12 7.36 8.34 9.66 10.7 11.8 12.8 14.3 I 15.5
(4.83-5.50) (5.73-6.54) (6.89-7.87) (7.79-8.91) (9.00-10.3) (9.95-11.4) (10.9-12.6) (11.9-13.8) (13.2-15.4) (14.2-16.6)
20-day 6.86 8.10 9.57 10.7 12.3 13.5 14.8 16.0 17.7 19.1
(6.46-7.31) (7.62-8.64) (8.99-10.2) (10.1-11.4) (11.5-13.1) (12.6-14.4) (13.7-15.7) (14.9-17.1) (16.4-19.0) (17.6-20.4)
30-day 8.42 9.90 11.5 12.8 14.4 15.7 17.0 18.2 19.9 21.2
(7.94-8.95) (9.34-10.5) (10.9-12.3) (12.0-13.6) (13.6-15.4) (14.7-16.7)_ (15.9-18.1) (17.0-19.4) (18.5-21.3) (19.6-22.7)
45-day 10.6 12.4 14.2 15.6 17.3 18.7 20.0 21.3 23.0 24.3
(10.1-11.2) (11.8-13.1) (13.5-14.9) (14.7-16.4) (16.4-18.2) (17.7-19.7) (18.9-21.1) (20.0-22.5) (21.6-24.3) (22.7-25.7)
60-day 12.6 14.7 16.6 18.1 20.0 21.5 22.8 24.2 26.0 27.3
(12.0-13.2) (14.0-15.4) (15.8-17.4) (17.2-19.0) (19.0-21.0) (20.4-22.6) (21.6-24.0) (22.9-25.5) (24.5-27.4) 1 (25.7-28.8)
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_pri ntpage.html?lat=34.9950&Ion=-80.8240&data=depth&units=english&series=pds 1/4

1/16/23, 12:39 PM Precipitation Frequency Data Server
NOAA Atlas 14,Volume 2,Version 3
u .Location name: Marvin, North Carolina,USA* .' '�''
XaA Latitude: 34.995°, Longitude: -80.824° norm
Elevation:671.72 ft**
��+` *source:ESRI Maps 'y
�`$`� **source:USGS �,"""`�
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M.Bonnin,D.Martin,B.Lin,T.Parzybok,M.Yekta,and D.Riley
NOAA,National Weather Service,Silver Spring,Maryland
PF tabular I PF graphical I Maps & aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches/hour)1
Average recurrence interval(years)
Duration 1 2 5 10 25 50 100 200 500 1000
5-min 4.99 5.89 6.84 7.54 8.34 8.88 9.40 9.85 10.4 10.7
(4.61-5.42) (5.42-6.41) (6.29-7.44) (6.91-8.17) (7.61-9.02) (8.08-9.62) (8.50-10.2) (8.86-10.7) (9.24-11.3) (9.49-11.7)
10-min 3.99 4.71 5.48 6.02 6.64 7.07 7.46 7.81 8.20 8.45
(3.68-4.33) (4.33-5.13) (5.03-5.96) (5.53-6.54) i (6.06-7.19) (6.43-7.66) (6.74-8.08) (7.02-8.46) (7.31-8.90) (7.48-9.19)
6
15-min 3.32 3.95 4.62 5.08 5.61 5.97 6.29 6.56 6.88 I 7.07
(3.06-3.60) (3.63-4.30) (4.24-5.03) (4.66-5.52) (5.12-6.08) (5.43-6.47) (5.68-6.81) (5.90-7.12) (6.13-7.47) ( .26-7.69)
30-min 2.28 2.73 3.28 3.68 4.16 4.50 4.82 5.11 5.47 5.73
(2.10-2.47) (2.51-2.97) (3.01-3.57) (3.37-4.00) `(3.79-4.50) (4.09-4.87) (4.35-5.21) (4.59-5.54) (4.88-5.94) (5.06-6.23)
60-min 1.42 1.71 2.10 2.40 2.77 3.05 3.32 3.58 3.93 4.18
(1.31-1.54) (1.57-1.86) (1.93-2.29) (2.20-2.60) (2.53-3.00) (2.77-3.30) (3.00-3.59) (3.22-3.88) (3.50-4.26) I (3.70-4.55)
2-hr 0.822 0.994 1.23 1.41 1.65 1.83 2.01 2.19 2.43 2.61
(0.752-0.900) (0.909-1.09) (1.12-1.35) (1.29-1.54) (1.50-1.80) (1.65-1.99) (1.81-2.19) (1.96-2.39) (2.15-2.65) (2.29-2.86)
3-hr 0.582 0.701 0.874 1.01 1.19 1.34 1.48 1.64 1.85 2.01
(0.532-0.640) (0.642-0.772) (0.798-0.960) (0.918-1.11) (1.08-1.30) (1.20-1.46) (1.33-1.62) (1.45-1.79)_ (1.62-2.02) (1.74-2.20)
6-hr 0.351 0.423 0.527 0.610 0.722 1 0.813 0.906 1.00 1.14 1.24
(0.321-0.385) (0.387-0.464) (0.482-0.578) (0.556-0.667) (0.655-0.788) (0.733-0.885) (0.811-0.986) (0.889-1.09) (0.994-1.24) (1.08-1.35)
12-hr 0.206 0.249 0.312 0.362 0.433 0.490 0.550 0.613 0.701 0.774
(0.189-0.226) (0.229-0.274) (0.286-0.342) (0.331-0.397) (0.392-0.472) (0.441-0.534) (0.490-0.598) (0.540-0.666) (0.608-0.762)I(0.662-0.841)
24-hr 0.122 0.148 0.185 0.215 0.256 0.289 0.323 0.359 0.407 0.446
(0.113-0.132) (0.137-0.160) (0.172-0.201) (0.199-0.233) (0.236-0.277) (0.266-0.312) (0.296-0.349) (0.327-0.388) (0.370-0.441) (0.403-0.484)
2-day 0.072 0.087 0.108 0.125 0.149 0.167 0.186 ' 0.206 0.234 0.255
(0.067-0.078) (0.081-0.094) (0.100-0.117) (0.116-0.136) (0.137-0.161) (0.153-0.181) (0.170-0.202)1(0.188-0.224) (0.212-0.254) (0.230-0.278)
3-day 0.051 0.061 0.076 0.088 0.104 0.117 0.130 0.143 0.162 0.178
(0.047-0.055) (0.057-0.066) (0.070-0.082) (0.081-0.095) (0.096-0.112) (0.107-0.126) (0.119-0.140) (0.131-0.155) (0.148-0.176) (0.161-0.193)
4-day 0.040 0.049 0.060 0.069 0.081 0.091 0.102 0.112 0.127 0.139
(0.038-0.044) (0.045-0.052) (0.056-0.065) (0.064-0.074) (0.075-0.088) (0.084-0.099) (0.093-0.110) (0.103-0.121) (0.116-0.138) (0.126-0.150)
7-day 0.027 0.032 0.039 0.045 0.052 0.058 0.065 0.071 0.080 0.088
(0.025-0.029) (0.030-0.034) (0.036-0.042) (0.042-0.048) (0.049-0.056) (0.054-0.063) (0.060-0.069) (0.066-0.076) (0.074-0.086) (0.080-0.094)
10-day 0.021 0.025 0.031 0.035 0.040 0.045 0.049 0.053 0.060 0.064
(0.020-0.023) (0.024-0.027) (0.029-0.033) (0.032-0.037) (0.038-0.043) (0.041-0.048) (0.045-0.052) (0.049-0.057) (0.055-0.064) (0.059-0.069)
20-day 0.014 0.017 0.020 0.022 0.026 0.028 0.031 0.033 0.037 0.040
(0.013-0.015) (0.016-0.018) (0.019-0.021) (0.021-0.024) (0.024-0.027) (0.026-0.030) (0.029-0.033) (0.031-0.036) (0.034-0.040) (0.037-0.043)
30-day 0.012 0.014 0.016 0.018 0.020 0.022 0.024 0.025 0.028 0.029
(0.011-0.012) (0.013-0.015) (0.015-0.017) (0.017-0.019) (0.019-0.021) (0.020-0.023) (0.022-0.025) (0.024-0.027) (0.026-0.030) (0.027-0.032)
45-day 0.010 0.011 0.013 0.014 0.016 0.017 0.019 0.020 0.021 0.022
(0.009-0.010) (0.011-0.012) (0.012-0.014) (0.014-0.015) (0.015-0.017) (0.016-0.018) (0.017-0.020) (0.019-0.021) (0.020-0.023) (0.021-0.024)
60-day 0.009 0.010 0.012 0.013 0.014 0.015 0.016 0.017 0.018 0.019
(0.008-0.009) (0.010-0.011) (0.011-0.012) (0.012-0.013) (0.013-0.015) (0.014-0.016) (0.015-0.017) (0.016-0.018) (0.017-0.019) (0.018-0.020)
1 Precipitation frequency(PF)estimates in this table are based on frequency analysis of 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_pri ntpage.html?lat=34.9950&Ion=-80.8240&data=intensity&units=english&series=pds 1/4

APPENDIX B
PERMANENT STORMWATER CALCULATIONS

WET POND CALCULATIONS

\ �
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� \ �\NORTH \ \ � -_= s� �� � \
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h, , 1,,,,,1 III 1 1 J / \,\ ?..e._, ;- - NI,-‹� —80��--_,,,,,,,,, ;_-_-, ,_-_---z,-..---_-,,----__-_-__.---��� ,���69 � -\ \ , -\�
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/% /// / /////////� ; DRAINAGE AREA 2 \`� �\�\�� \ \ „\
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i I 1
// // / 0• /// / . TOTAL DA: 24.08 AC===. �J� \\\\ ��\\� \ \ \ \
'N /kc/: I
/ 5� / // y / (— Q10 = 19.34 CFS S5_1 �� \\ ��� 6j\ `80N\ \ \\ \\ � i
/6� —�i /�// /6// / / 1 1 —_ �.. �\\\ �\ \sue
N \ .\�/ � /J(��/�/�// ( ( 6� ) I 1 /sss�� \�660�=� ���1���0 ���\\\\ \\\ \ 2i ,�
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a _,v/ �021 cn \o\\(/( � rJ/ 6g0 ��:650� �I I I I — / �
�/i=--�sao\ \\;1\ �IAO\ \ / , \ \ I Ihl �/ / / I I IIII IIII ' \ ll_.• \� /l�\ ��j, ,---� \, i\III \ 1l / //—�/ —7I \ I I I \ \ l \ I I 1 III II I I I I l \ 1 �i/ /�i —0% \\\�\ 111\11�\\ l\\�I I I I ( ( \� \ 1 I \ �\ \ I I \ \\\ \ 1 ( 1 11I,1 I 1 1 \ /\ //
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`Al 1\ l I I 1 ( ,_ \ \\\�\ \ \ \\\\\\\\\\ co \ \ \�\ \\ 1�,1 \ \ \ ) 1 / %':5----_--_ — I 1 I IIIII \\ \ \ \ 1 \\01 o\ 1 / / / //
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-- \ \\ I \I I \ \\ \ \\\\ \\\\\\\ 1 � \\ \ \\\o\� \\�\\\\\`\\\ \\ \ \\ \\\\\III I I \\\\ \ TOTAL Tc - 92.6 MIN.
\ \\ "I' 1„ \\� \\\'1\ \\elll \ \ \ \ \ \ \\\\\\ \ \\ \ 1 I \ \ \ �/.
fr) 1 lo°oll I o°'o\Iv\Ivl\'�I I IO1I I I �,I Ito \ \ > 1 \ \\ \\\\\ \ \ I
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\ 1I \' I II'1 /// IIJ �Ir \\ /ih\��/;� /o,/i/ 11\ I1 II �\ \\ e
I I I I II I I I II I IIIII I I / /// I \ ( /// ////% =/,66 i / /h l ) I(1 \\ �o ////
' TOTAL Tc = 55.0 MIN. /. / I / I III lI / // / ��_,� // 0 1I 1 \
l /l 11/ IIII 1111 I l // // \ J \ /// /„, 11 o /
685 —J//l/illlil/Jli1/I'll0 Ill///l�//i // \ \ ////�//yy//��� —moo// //^I I \��f�/
ce l J 111171/ll 11 ll//// /// - \ / 7/� / '//'t6�/6._ J7i7/ 1 (r�
k -7//(o// /o//n, 11$' ". 'i "/,
/l /�/j�l,�o/ o /h/ //l.✓i ///l'� /O /1 I r p 1,7 , `-/j //l/ i //h///� 1 .....•..:i /2 1 icl ( ( )`\�\\� 6 (,� -: ��i�� PRE-DEVELOPMENT
. 6-s '�/i/�// 11 l////l IA // /�l 4\\\\NNNX `\ I // ��%� 7
/ / / / �\\ \\ \\\\\\\� I 1 �� //// �i )I'I,PRE-DEVELOPMENT 10 4 \\\\\ \ / J l /� TOTAL D 9.78 S C������1// / \ \\ // //
/h // / ( iI \ \� I1 \ l l/01111�
TOTAL DA: 4.4 AC 0���—-�// b / I 1 I I 1 1 I\_ / ^ I
° TOT = 3.86 CFS ((//��J���/)',z, `°11 \ ��,(pi 11 1�1 I III /�o///�y /
Q101\ 1 .//ter / /A),til i 6/ / 1 1 II Lt\\ \\�� / /// b//
o
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a \ ',lhh//(/ \ o\Tzill \\\�\\\\\'///IIlII/
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I I V \(\j; —PRE-DEVELOPMENT \\\\--/ /
o / I \ \ r DRAINAGE AREA ENTIRE SITE \ /)//)/
o I / I, \ ANALYSIS POINT
1 TOTAL DA: 38.26 AC \`�ss�-
\ 1 Q10 = 28.81
o \ /\
o \
3 / \
o i r i HERITAGE AT MARVIN
o SCALE IN FEET ,-,= - SINGLE-FAMILY SUBDIVISION
Civil & Environmental Consultants, Inc.
JCHNC, LLC
0 200 400MARVIN, NORTH CAROLINA
co 3701 Arco Corporate Drive•Suite 400•Charlotte, NC 28273
REFERENCE Ph:980.237.0373-Fax:[phone] PRE-DEVELOPMENT DRAINAGE MAP
0
www.cecinc.com
0
1. TOPOGRAPHICAL SURVEY PERFORMED BY LAND SURVEYING, DRAWN BY: FAA CHECKED BY: CAP APPROVED BY: MLG FIGURE NO.:
INC.; DATE JANUARY 19, 2022 DATE: NOVEMBER 2023 DWG SCALE: 1"=200' PROJECT NO: 326-256 HYD-1

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\ TOTAL Tc = 5 MIN. �% "� --_ ; 7',i i &i'Ar"n"..,,,,,./////// ,-k \'‘\ N
,i), 1 Ili __ _
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�' �'Ns-tk‘ !it aIrtt .r � TOTAL Tc = 5 MIN. �. V N
POST DEVELOPMENT ter, , �j� wit �� n Ii *1 ' A1/2\
a /DRAINAGE AREA 1 /44,41:A
/ �� I� `
IMPERVIOUS: 5.96 AC � ♦ �il�l ": it
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EXISTING BUA: 0.62 AC ,�� t.. I•—_._ ,„„�.�/,', 4:' ., )- ‘•:,
rn PERVIOUS: 12.41 AC /��� \ �..�!� - y �� � /o TOTAL DA: 18.99 AC „„ / \ , � �� � ,� // �t ��
\ ��' _.. , \., -- , ' �v.A ,' �.,� ������ �� POST-DEVELOPMENT\ e .;� � c �r ��� r' :' i� ��� DRAINAGE AREA 2
a �� •
�9� �til�_ Wyk �`� /.' ,o,%� • I "1 •J �, ��� �� IMPERVIOUS: 6.88 AC
�� �,/ ♦ �� �` «�' '' j �/ �,j►�� / EXISTING BUA: 0.63 AC
�� �� /io�� �� `. ' •, ,„ /-� v /--- 2)) PERVIOUS: 14.56 AC
•rl •-- •*, I / ..."1, \ ;14111:;••• \ \' y *k
j° ' �4 \� `0 ./ j/ ♦i /j/� � •\� � ,� �����1 �� % k� �� TOTAL DA: 22.07 AC
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HERITAGE AT MARVIN
SCALE IN FEET SINGLE-FAMILY SUBDIVISION
i . — I JCH NC, LLC
Civil & Environmental Consultants, Inc.
0 200 400MARVIN, NORTH CAROLINA
N 3701 Arco Corporate Drive•Suite 400•Charlotte, NC 28273
"' Ph:980.237.0373•Fax:[phone] POST-DEVELOPMENT DRAINAGE MAP
REFERENCE www.cecinc.com
o
R, 1. TOPOGRAPHICAL SURVEY PERFORMED BY LAND SURVEYING, DRAWN BY: ERR CHECKED BY: CAP APPROVED BY: MLG FIGURE NO.:
INC.; DATE JANUARY 19, 2022 DATE: NOVEMEBER 2023 DWG SCALE: 1"=200' PROJECT NO: 326-256 HYD-4
a

Project Name: Heritage At Marvin
BMP WetPond#: 1
BMP WETPOND SUMMARY CHART
PEAK CONTROL PRE- POST- POST
STORM EVENTS DEVELOPMENT DEVELOPMENT DEVELOPMENT ELEVATION
*values taken from RUNOFF RUNOFF OUTFLOW
hydrographs
Top of Berm 650.
1
100YR-24HR 37.24 CFS 147.40 I CFS 69.48 I CFS I 649.38
50YR-24HR I 30.09 CFS 125.26 I CFS I 53.43 I CFS I 648.93
25YR-24HR 23.51 CFS 104.20 CFS 27.07 I CFS I 648.54
10YR-24HR 15.88 CFS 78.66 CFS 5.70 CFS 648.19
2YR-24HR 5.39 CFS 39.96 CFS 0.26 CFS 647.62
1YR-24HR 2.66 CFS 27.07 CFS 0.21 CFS 646.E
Er
Page 1 of 6 Civil& Environmental Consultants,Inc.

COMPOSITE CURVE NUMBERS (CN)
Project Area Soil Types= See attached Soils Report Input
Calculated
Pre-Construction Conditions:
Pre-Drainage Area-Entire Site
Area Area
Cover Type/Condition Soil Classification CN (SF) (AC)
Woods-Good Condition B 55 493,428 11.33
Woods-Good Condition C 70 166,845 3.83
Woods-Good Condition D 77 166,845 3.83
B 0 0 0.00
B _ 0 0 0.00
TOTAL: 62.5 827,118 18.99
*NCDEQ Table 4:HSGs for NC Soil Types-Urban Areas Runoff Curve Numbers for SCS Method
NCDEQ Stormwater Design Manual Revised 3-15-2017
Post-Construction Conditions:
Post-Drainage Area#1
Cover Type/Condition Soil Classification CN Area Area
(SF) (AC)
Impervious B 98 292,054 6.70
Grass-Good Condition B 61 463,495 10.64
Woods-Good Condition B 55 71,569 1.64
B 0 0 0.00
D 0 0 0.00
TOTAL: 73.5 827,118 18.99
V IFL7
Page 2 of 6 Civil& Environmental Consultants,Inc.

Water Quality Calculations
Input
Calculated
Drainage Area 18.99 ac SA/DA Ratio
Impervious Area 6.70 ac %Impervious Permanent Pool Average Depth(ft)
Impervious% 35% Cover 3.00 3.50 4.00
30% 1.17 1.06 0.94
Estimated Avg.Depth 3.50 ft 35% 1.33 1.21 1.08
SA/DA Ratio 1.21 % 40% 1.51 1.38 1.24
SA Required 0.23 ac *C-3 Table 1(Piedmont and Mountain Region)
SA Required 9,967 sf (NCDEQ BMP Design Manual revised 11-23-2020)
Main Pool Calculations
*Average Depth calculations are based on Equation 3 of Wet Pond MDC 2 of the NCDEQ Stormwater Design Manual
Main Pool Provided Depth 3.50 ft DMAx 0.50 ft
Cale Avg.Depth 3.21 Perimeterpp 553.00 ft
SA Provided 18,137 sf (PROCEED) I WidthsusMERG 3.00 ft
SA Provided 0.42 ac VSHELF 414.75 cf
Volume Calculation(Average End Method)
Stage Elevation Area Inc.Vol. Acc Vol.
(ft) (ft) (sf) (cf) (cf)
641.00 Bottom of Sediment Removal
0.00 641.50 13,560 0 0 Top of Sediment Removal
1.00 642.50 14,585 14,073 14,073
2.00 643.50 15,641 15,113 29,186
3.00 644.50 16,723 16,182 45,368 Bottom of Shelf
3.50 645.00 18,137 8,715 54,083 Permanent Pool
N/A N/A 0 N/A N/A
N/A N/A 0 N/A N/A
N/A N/A 0 N/A N/A
N/A N/A 0 N/A N/A
N/A N/A 0 N/A N/A
N/A N/A 0 N/A N/A
N/A N/A 0 N/A N/A
N/A N/A 0 N/A N/A
N/A N/A 0 N/A N/A
MI
Page 3 of 6 Civil&Environmental Consultants,Inc.

Temporary Pool Calculations
Rv=0.05+0.9*IA SIMPLE METHOD PER NCDEQ BMP MANUAL SECTION 3.3.1
WQv=3630*RD*Rv*A Rv=Runoff coefficient[storm runoff(in)/storm rainfall(in)],unitless
IA=Impervious fraction[impervious portion of drainage area(ac)/drainage area(ac)],unitless
**V=Volume of runoff that must be controlled for the design storm(ft3)
RD=Design storm rainfall depth(in)(Typically, 1.0"or 1.5")
A=Watershed area(ac)
Rv 0.37 (Design Storm=1 inch)
WQv required 25,350 cfs
WQv provided 25,662 cfs (PROCEED)
Temp.Pool Provided Depth 5.00 ft
Volume Calculation(Average End Method)
Stage Elevation Area Inc.Vol. Acc Vol.
(ft) (ft) (sf) (cf) (cf)
0.00 645.00 18,137 0 0 Permanent Pool
0.50 645.50 24,039 10,544 10,544 Top of Shelf
1.00 646.00 25,993 12,508 23,052
1.50 646.50 27,060 13,263 36,315
2.00 647.00 28,141 13,800 50,116
2.50 647.50 29,237 14,345 64,460
3.00 648.00 30,347 14,896 79,356 Top of Riser
3.50 648.50 31,470 15,454 94,810
4.00 649.00 32,608 16,020 110,830
4.50 649.50 33,760 16,592 127,422
5.00 650.00 34,926 17,172 144,593 Top of Dam(allow 1 ft FB)
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
Assumed Stage Interval for Treatment of WQv 646.00
Interpolate 0.10 area between even stages at WQv stage
Volume Calculation(Average End Method)
Stage Elevation Area Inc.Vol. Acc Vol.
(ft) (ft) (sf) (cf) (cf)
0.00 646.00 25,993 12,508 23,052
0.10 646.10 26,208 2,610 25,662
0.20 646.20 26,423 2,632 28,294
0.30 646.30 26,637 2,653 30,947
0.40 646.40 26,852 2,674 33,621
0.50 646.50 27,067 2,696 36,317
0.60 646.60 27,282 2,717 39,034
0.70 646.70 27,497 2,739 41,773
0.80 646.80 27,711 2,760 44,534
0.90 646.90 27,926 2,782 47,316
1.00 647.00 28,141 2,803 50,119
Calc WQV Elevation 646.10 J
MI
Page 4 of 6 Civil&Environmental Consultants,Inc.

Water Quality Orifice Size Calculation
Treatment Vol 25,662 CF 25,662
Draw Down Time 2 DAYS 5 (NCDEQ required time frame)
Draw Down Time 172,800 sec 432,000
Flow(Q) 0.149 CFS 0.059
Cd 0.6 0.6
H/3 0.367 ft 0.367
Area of orifice 0.051 sf 0.020
Max orifice diameter 3.06 in 1.93 Min orifice diameter
Orifice Size Used(Dia.) 2.50 in PROCEED
Draw Down Time 2.94 DAYS PROCEED
Forebay Volume Calculation
Forbay Provided Depth 3.00 ft
Volume Calculation(Average End Method)
Stage Elevation Area Inc.Vol. Acc Vol.
(ft) (ft) (sf) (cf) (cf)
641.50 Bottom of Sediment Removal
0.00 642.00 2,202 0 , Top of Sediment Removal
0.50 642.50 2,480 1,171 1,171
1.00 643.00 2,774 1,314 2,484
1.50 643.50 3,082 1,464 3,948
2.00 644.00 3,404 1,622 5,570
2.50 644.50 3,741 1,786 7,356
3.00 645.00 4,092 1,958 9,314
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
15%Permanent Pool Volume 8,112
20%Permanent Pool Volume 10,817
Forebay Volume Provided 9,314
Proceed
17%
MI
Page 5 of 6 Civil&Environmental Consultants,Inc.

ANTI-FLOTATION ANCHOR
update area calculations for rectangular or circular riser
Riser Inside Dimensions(ft)-square conc structure only 5.00 structures
Riser Inside Area(sf) 25.00 Density of concrete(Ibs/cf) 150.00
Riser Outside Dimensions(ft)-square conc structure only 6.00
Riser Outside Area(sf) 36.00 Density of water(Ibs/cf) 62.40
Riser Structure Height(ft) 4.00
WEIGHT DISPLACE BY RISER(Ibs) 6,240.00
Area of concrete(sf)-assume 6"wall thickness 11.00 Anchor Dimension(n x n)(ft) 7.00
Riser Structure Height(ft) 4.00 Anchor Thickness(ft) 1.50
Volume of Riser concrete(cf) 44.00 Anchor Area(sf) 49.00
Net Displaced by the Riser(Ibs/cf) 87.60 Anchor Volume(cf) 96.00
WEIGHT OF THE CONCRETE RISER(Ibs) 3,854.40 WEIGHT OF ANCHOR(Ibs) 14,400.00
WEIGHT OF RISER&ANCHOR vs WEIGHT DISPLACED BY RISER OK
ANTI-SEEP COLLAR
Barell Size(in) 30
Anti-Seep Collar Size(ft x ft) 6.5 Provide min.two(2)6.5'x 6.5'anti-seep collars
assume 6"thickness on pipe barrel and min.1.5 feet
• Protection against piping-Install at least one watertight anti-seep collar projection around barrel(thickness may vary depending
with a minimum projection of 1.5 feet around the barrel of principal on barrel type)
spillway conduits,8 inches or larger in diameter. Locate the anti-seep
collar slightly downstream from the dam center line. A properly
designed drainage diaphragm installed around the barrel may be used
instead of an anti-seep collar when it is appropriate.
1'FREEBOARD EMBANKMENT
HEAD ABOVE OUTLET
END OF BARREL
EMERGENCY SPILLWAY
r
HEAD ABOVE PRINCIPAL
RISER CREST SPILLWAY
BARREL DIA.
r,/L/
Page 6 of 6 Civil&Environmental Consultants,Inc.

Project Name: Heritage At Marvin
BMP WetPond#: 2
BMP WETPOND SUMMARY CHART
PEAK CONTROL PRE- POST- POST
STORM EVENTS DEVELOPMENT DEVELOPMENT DEVELOPMENT ELEVATION
*values taken from RUNOFF RUNOFF OUTFLOW
hydrographs
Top of Berm 650.00
100YR-24HR I 39.90 CFS 175.51 CFS 47.67 CFS 648.80
50YR-24HR L 32.05 LCFS 149.18 CFS 18.78 CFS 648.42
25YR-24HR 24.84 CFS 123.51 CFS I 7.57 CFS 648.22
10YR-24HR 16.54 CFS 92.48 CFS 2.13 CFS 648.08
2YR-24HR 5.36 CFS 45.61 CFS 0.32 CFS 646.91
1YR-24HR 2.56 CFS 30.12 CFS 0.25 CFS 646.28
L -
Page 1 of 6 Civil& Environmental Consultants,Inc.

COMPOSITE CURVE NUMBERS (CN)
Project Area Soil Types= See attached Soils Report Input
Calculated
Pre-Construction Conditions:
Pre-Drainage Area-Entire Site
Cover Type/Condition Soil Classification CN Area Area
(SF) (AC)
Woods-Good Condition B 55 657,342 15.09
Woods-Good Condition C 70 80,561 1.85
Woods-Good Condition D 77 223,564 5.13
B 0 0 0.00
D _ 0 0 0.00
TOTAL: 61.4 961,467 22.07
*NCDEQ Table 4:HSGs for NC Soil Types-Urban Areas Runoff Curve Numbers for SCS Method
NCDEQ Stormwater Design Manual Revised 3-15-2017
Post-Construction Conditions:
Post-Drainage Area#2
Cover Type/Condition Soil Classification CN Area Area
(SF) (AC)
Impervious B 98 331,293 7.61
Grass-Good Condition B 61 461,945 10.60
Woods-Good Condition B 55 168,229 3.86
B 0 0 0.00
D 0 0 0.00
TOTAL: 72.7 961,467 22.07
Er
Page 2 of 6 Civil& Environmental Consultants,Inc.

Water Quality Calculations
Input
Calculated
Drainage Area 22.07 ac SA/DA Ratio
Impervious Area 7.61 ac %Impervious Permanent Pool Average Depth(ft)
Impervious% 34% Cover 3.00 3.50 4.00
30% 1.17 1.06 0.94
Estimated Avg.Depth 3.50 ft 34% 1.36 1.23 1.11
SA/DA Ratio 1.23 % 40% 1.51 1.38 1.24
SA Required 0.27 ac *C-3 Table 1(Piedmont and Mountain Region)
SA Required 11,849 sf (NCDEQ BMP Design Manual revised 11-23-2020)
Main Pool Calculations
*Average Depth calculations are based on Equation 3 of Wet Pond MDC 2 of the NCDEQ Stormwater Design Manual
Main Pool Provided Depth 3.50 ft DMAx 0.50 ft
Calc Avg.Depth 3.35 Perimeterpp 655.00 ft
SA Provided 29,626 sf (PROCEED) I WidthsuBMERG 3.00 ft
SA Provided 0.68 ac VsHELF 491.25 cf
Volume Calculation(Average End Method)
Stage Elevation Area Inc.Vol. Acc Vol.
(ft) (ft) (sf) (cf) (cf)
641.00 Bottom of Sediment Removal
0.00 641.50 23,939 0 0 Top of Sediment Removal
1.00 642.50 25,227 24,583 24,583
2.00 643.50 26,548 25,888 50,471
3.00 644.50 27,222 26,885 77,356 Bottom of Shelf
3.50 645.00 29,626 14,212 91,568 Permanent Pool
N/A N/A 0 N/A N/A
N/A N/A 0 N/A N/A
N/A N/A 0 N/A N/A
N/A N/A 0 N/A N/A
N/A N/A 0 N/A N/A
N/A N/A 0 N/A N/A
N/A N/A 0 N/A N/A
N/A N/A 0 N/A N/A
N/A N/A 0 N/A N/A
MI
Page 3 of 6 Civil&Environmental Consultants,Inc.

Temporary Pool Calculations
Rv=0.05+0.9*IA SIMPLE METHOD PER NCDEQ BMP MANUAL SECTION 3.3.1
WQv=3630*RD*Rv*A Rv=Runoff coefficient[storm runoff(in)/storm rainfall(in)],unitless
IA=Impervious fraction[impervious portion of drainage area(ac)/drainage area(ac)],unitless
**V=Volume of runoff that must be controlled for the design storm(ft3)
RD=Design storm rainfall depth(in)(Typically, 1.0"or 1.5")
A=Watershed area(ac)
Rv 0.36 (Design Storm=1 inch)
WQv required 28,853 cfs
WQv provided 32,586 cfs (PROCEED)
Temp.Pool Provided Depth 5.00 ft
Volume Calculation(Average End Method)
Stage Elevation Area Inc.Vol. Acc Vol.
(ft) (ft) (sf) (cf) (cf)
0.00 645.00 29,626 0 0 Permanent Pool
0.50 645.50 38,281 16,977 16,977 Top of Shelf
1.00 646.00 40,740 19,755 36,732
1.50 646.50 41,994 20,684 57,416
2.00 647.00 43,262 21,314 78,730
2.50 647.50 44,543 21,951 100,681
3.00 648.00 45,839 22,596 123,276 Top of Riser
3.50 648.50 47,150 23,247 146,524
4.00 649.00 48,474 23,906 170,430
4.50 649.50 49,812 24,572 195,001
5.00 650.00 51,165 25,244 220,245 Top of Dam(allow 1 ft FB)
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
Assumed Stage Interval for Treatment of WQv 645.50
Interpolate 0.10 area between even stages at WQv stage
Volume Calculation(Average End Method)
Stage Elevation Area Inc.Vol. Acc Vol.
(ft) (ft) (sf) (cf) (cf)
0.00 645.50 38,281 16,977 16,977
0.10 645.60 38,652 3,847 20,823
0.20 645.70 39,024 3,884 24,707
0.30 645.80 39,395 3,921 28,628
0.40 645.90 39,766 3,958 32,586
0.50 646.00 40,138 3,995 36,581
0.60 646.10 40,509 4,032 40,614
0.70 646.20 40,880 4,069 44,683
0.80 646.30 41,251 4,107 48,790
0.90 646.40 41,623 4,144 52,933
1.00 646.50 41,994 4,181 57,114
Calc WQV Elevation 645.90 J
MI
Page 4 of 6 Civil&Environmental Consultants,Inc.

Water Quality Orifice Size Calculation
Treatment Vol 32,586 CF 32,586
Draw Down Time 2 DAYS 5 (NCDEQ required time frame)
Draw Down Time 172,800 sec 432,000
Flow(Q) 0.189 CFS 0.075
Cd 0.6 0.6
H/3 0.300 ft 0.300
Area of orifice 0.072 sf 0.029
Max orifice diameter 3.62 in 2.29 Min orifice diameter
Orifice Size Used(Dia.) 3.00 in PROCEED
Draw Down Time 2.86 DAYS PROCEED
Forebay Volume Calculation
Forbay Provided Depth 3.00 ft
Volume Calculation(Average End Method)
Stage Elevation Area Inc.Vol. Acc Vol.
(ft) (ft) (sf) (cf) (cf)
641.50 Bottom of Sediment Removal
0.00 642.00 4,064 0 Top of Sediment Removal
0.50 642.50 4,425 2,122 2,122
1.00 643.00 4,801 2,307 4,429
1.50 643.50 5,191 2,498 6,927
2.00 644.00 5,593 2,696 9,623
2.50 644.50 6,010 2,901 12,524
3.00 645.00 6,441 3,113 15,636
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
N/A N/A N/A N/A
15%Permanent Pool Volume 13,735 _
20%Permanent Pool Volume 18,314 _
Forebay Volume Provided 15,636
Proceed
17%
MI
Page 5 of 6 Civil&Environmental Consultants,Inc.

ANTI-FLOTATION ANCHOR
update area calculations for rectangular or circular riser
Riser Inside Dimensions(ft)-square conc structure only 6.00 structures
Riser Inside Area(sf) 36.00 Density of concrete(Ibs/cf) 150.00
Riser Outside Dimensions(ft)-square conc structure only 7.00
Riser Outside Area(sf) 49.00 Density of water(Ibs/cf) 62.40
Riser Structure Height(ft) 4.00
WEIGHT DISPLACE BY RISER(Ibs) 8,985.60
Area of concrete(sf)-assume 6"wall thickness 13.00 Anchor Dimension(n x n)(ft) 8.00
Riser Structure Height(ft) 4.00 Anchor Thickness(ft) 1.50
Volume of Riser concrete(cf) 52.00 Anchor Area(sf) 64.00
Net Displaced by the Riser(Ibs/cf) 87.60 Anchor Volume(cf) 96.00
WEIGHT OF THE CONCRETE RISER(Ibs) 4,555.20 WEIGHT OF ANCHOR(Ibs) 14,400.00
WEIGHT OF RISER&ANCHOR vs WEIGHT DISPLACED BY RISER OK
ANTI-SEEP COLLAR
Barell Size(in) 36
Anti-Seep Collar Size(ft x ft) 7.0 Provide min.two(2)7.0'x 7.0'anti-seep collars
assume 6"thickness on pipe barrel and min.1.5 feet
• Protection against piping-Install at least one watertight anti-seep collar projection around barrel(thickness may vary depending
with a minimum projection of 1.5 feet around the barrel of principal on barrel type)
spillway conduits,8 inches or larger in diameter. Locate the anti-seep
collar slightly downstream from the dam center line. A properly
designed drainage diaphragm installed around the barrel may be used
instead of an anti-seep collar when it is appropriate.
1'FREEBOARD EMBANKMENT
HEAD ABOVE OUTLET
END OF BARREL
EMERGENCY SPILLWAY
r
HEAD ABOVE PRINCIPAL
RISER CREST SPILLWAY
BARREL DIA.
r,/L/
Page 6 of 6 Civil&Environmental Consultants,Inc.

Hydraflow Table of Contents 326256-Heritage at Marvin-Wetponds Hydrogprah.gpw
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2022 Monday, 10/16/2023
Watershed Model Schematic 1
Hydrograph Return Period Recap 2
1 - Year
Summary Report 3
Hydrograph Reports 4
Hydrograph No. 1, SCS Runoff, Pre-Drainage Area #1 4
Hydrograph No. 2, SCS Runoff, Pre-Drainage Area #2 5
Hydrograph No. 3, SCS Runoff, Pre-Drainage Area #3 6
Hydrograph No. 4, Combine, Pre-Development Discharge Rate 7
Hydrograph No. 5, SCS Runoff, Post-Development Drainage Area #1 8
Hydrograph No. 6, Reservoir, Wetpond #1 9
Hydrograph No. 7, SCS Runoff, Post-Development Drainage Area #2 10
Hydrograph No. 8, Reservoir, Wet Pond #2 11
Hydrograph No. 9, Combine, Post-Development Discharge Rate 12
2 - Year
Summary Report 13
Hydrograph Reports 14
Hydrograph No. 1, SCS Runoff, Pre-Drainage Area #1 14
Hydrograph No. 2, SCS Runoff, Pre-Drainage Area #2 15
Hydrograph No. 3, SCS Runoff, Pre-Drainage Area #3 16
Hydrograph No. 4, Combine, Pre-Development Discharge Rate 17
Hydrograph No. 5, SCS Runoff, Post-Development Drainage Area #1 18
Hydrograph No. 6, Reservoir, Wetpond #1 19
Hydrograph No. 7, SCS Runoff, Post-Development Drainage Area #2 20
Hydrograph No. 8, Reservoir, Wet Pond #2 21
Hydrograph No. 9, Combine, Post-Development Discharge Rate 22
5 - Year
Summary Report 23
Hydrograph Reports 24
Hydrograph No. 1, SCS Runoff, Pre-Drainage Area #1 24
Hydrograph No. 2, SCS Runoff, Pre-Drainage Area #2 25
Hydrograph No. 3, SCS Runoff, Pre-Drainage Area #3 26
Hydrograph No. 4, Combine, Pre-Development Discharge Rate 27
Hydrograph No. 5, SCS Runoff, Post-Development Drainage Area #1 28
Hydrograph No. 6, Reservoir, Wetpond #1 29
Hydrograph No. 7, SCS Runoff, Post-Development Drainage Area #2 30
Hydrograph No. 8, Reservoir, Wet Pond #2 31
Hydrograph No. 9, Combine, Post-Development Discharge Rate 32
10 - Year
Summary Report 33
Hydrograph Reports 34
Hydrograph No. 1, SCS Runoff, Pre-Drainage Area #1 34
Hydrograph No. 2, SCS Runoff, Pre-Drainage Area #2 35

Contents continued... 326256-Heritage at Marvin-Wetponds Hydrogprah.gpw
Hydrograph No. 3, SCS Runoff, Pre-Drainage Area #3 36
Hydrograph No. 4, Combine, Pre-Development Discharge Rate 37
Hydrograph No. 5, SCS Runoff, Post-Development Drainage Area #1 38
Hydrograph No. 6, Reservoir, Wetpond #1 39
Hydrograph No. 7, SCS Runoff, Post-Development Drainage Area #2 40
Hydrograph No. 8, Reservoir, Wet Pond #2 41
Hydrograph No. 9, Combine, Post-Development Discharge Rate 42
25 - Year
Summary Report 43
Hydrograph Reports 44
Hydrograph No. 1, SCS Runoff, Pre-Drainage Area #1 44
Hydrograph No. 2, SCS Runoff, Pre-Drainage Area #2 45
Hydrograph No. 3, SCS Runoff, Pre-Drainage Area #3 46
Hydrograph No. 4, Combine, Pre-Development Discharge Rate 47
Hydrograph No. 5, SCS Runoff, Post-Development Drainage Area #1 48
Hydrograph No. 6, Reservoir, Wetpond #1 49
Hydrograph No. 7, SCS Runoff, Post-Development Drainage Area #2 50
Hydrograph No. 8, Reservoir, Wet Pond #2 51
Hydrograph No. 9, Combine, Post-Development Discharge Rate 52
50 - Year
Summary Report 53
Hydrograph Reports 54
Hydrograph No. 1, SCS Runoff, Pre-Drainage Area #1 54
Hydrograph No. 2, SCS Runoff, Pre-Drainage Area #2 55
Hydrograph No. 3, SCS Runoff, Pre-Drainage Area #3 56
Hydrograph No. 4, Combine, Pre-Development Discharge Rate 57
Hydrograph No. 5, SCS Runoff, Post-Development Drainage Area #1 58
Hydrograph No. 6, Reservoir, Wetpond #1 59
Hydrograph No. 7, SCS Runoff, Post-Development Drainage Area #2 60
Hydrograph No. 8, Reservoir, Wet Pond #2 61
Hydrograph No. 9, Combine, Post-Development Discharge Rate 62
100 - Year
Summary Report 63
Hydrograph Reports 64
Hydrograph No. 1, SCS Runoff, Pre-Drainage Area #1 64
Hydrograph No. 2, SCS Runoff, Pre-Drainage Area #2 65
Hydrograph No. 3, SCS Runoff, Pre-Drainage Area #3 66
Hydrograph No. 4, Combine, Pre-Development Discharge Rate 67
Hydrograph No. 5, SCS Runoff, Post-Development Drainage Area #1 68
Hydrograph No. 6, Reservoir, Wetpond #1 69
Hydrograph No. 7, SCS Runoff, Post-Development Drainage Area #2 70
Hydrograph No. 8, Reservoir, Wet Pond #2 71
Hydrograph No. 9, Combine, Post-Development Discharge Rate 72
IDF Report 73

1
Watershed Model Schematic Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024
1 2
4
3
6
11111
Project: 326256-Heritage at Marvin-Wetponds Hydrogprah.gpw Thursday, 11 / 16/2023

2
Hydrograph Return Period Recap Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024
Hyd. Hydrograph Inflow Peak Outflow(cfs) Hydrograph
No. type hyd(s) Description
(origin) 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr
1 SCS Runoff 2.664 5.391 10.82 15.88 23.51 30.09 37.24 Pre-Drainage Area#1
2 SCS Runoff 2.556 5.359 11.09 16.54 24.84 32.05 39.90 Pre-Drainage Area#2
3 Combine 1,2 5.207 10.73 21.85 32.39 48.25 61.96 76.86 Pre-Development Discharge Rate
4 SCS Runoff 27.07 39.96 61.08 78.66 104.20 125.26 147.40 Post-Development Drainage Area#1
5 Reservoir 4 0.214 0.260 1.792 5.699 27.07 53.43 69.48 Wetpond#1
6 SCS Runoff 29.88 44.59 68.81 89.04 118.31 142.65 168.27 Post-Development Drainage Area#2
7 Reservoir 6 0.254 0.315 0.395 2.125 7.571 18.80 48.16 Wet Pond#2
8 Combine 5, 7 0.469 0.576 2.146 6.063 27.46 68.51 115.50 Post-Development Discharge Rate
Proj. file: 326256-Heritage at Marvin-Wetponds Hydrogprah.gpw Thursday, 11 / 16/2023

3
Hydrograph Summary Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 2.664 2 754 26,759 Pre-Drainage Area#1
2 SCS Runoff 2.556 2 760 28,462 Pre-Drainage Area#2
3 Combine 5.207 2 758 55,221 1,2 Pre-Development Discharge Rate
4 SCS Runoff 27.07 2 718 54,630 Post-Development Drainage Area#1
5 Reservoir 0.214 2 1444 46,837 4 646.81 45,967 Wetpond#1
6 SCS Runoff 29.88 2 718 60,544 Post-Development Drainage Area#2
7 Reservoir 0.254 2 1442 52,380 6 646.28 50,325 Wet Pond#2
8 Combine 0.469 2 1442 99,217 5,7 Post-Development Discharge Rate
326256-Heritage at Marvin-Wetponds HydrogpRaltugpReriod: 1 Year Thursday, 11 / 16/2023

4
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 1
Pre-Drainage Area #1
Hydrograph type = SCS Runoff Peak discharge = 2.664 cfs
Storm frequency = 1 yrs Time to peak = 754 min
Time interval = 2 min Hyd. volume = 26,759 cuft
Drainage area = 18.990 ac Curve number = 62.5
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 55.30 min
Total precip. = 2.94 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Pre-Drainage Area #1
Q (cfs) Hyd. No. 1 -- 1 Year Q (cfs)
3.00 3.00
1
2.00 2.00
1.00 - 1.00
0.00 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 1 Time (min)

5
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 2
Pre-Drainage Area #2
Hydrograph type = SCS Runoff Peak discharge = 2.556 cfs
Storm frequency = 1 yrs Time to peak = 760 min
Time interval = 2 min Hyd. volume = 28,462 cuft
Drainage area = 22.070 ac Curve number = 61.4
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 59.80 min
Total precip. = 2.94 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Pre-Drainage Area #2
Q (cfs) Hyd. No. 2 -- 1 Year Q (cfs)
3.00 3.00
•
2.00 2.00
1.00 - 1.00
0.00 - - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 2 Time (min)

6
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 3
Pre-Development Discharge Rate
Hydrograph type = Combine Peak discharge = 5.207 cfs
Storm frequency = 1 yrs Time to peak = 758 min
Time interval = 2 min Hyd. volume = 55,221 cuft
Inflow hyds. = 1, 2 Contrib. drain. area = 41.060 ac
Pre-Development Discharge Rate
Q (cfs) Hyd. No. 3 -- 1 Year Q(cfs)
6.00 6.00
5.00 5.00
4.00 4.00
3.00 3.00
2.00 2.00
1.00 1.00
0.00 - , 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 3 Hyd No. 1 Hyd No. 2

7
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 4
Post-Development Drainage Area #1
Hydrograph type = SCS Runoff Peak discharge = 27.07 cfs
Storm frequency = 1 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 54,630 cuft
Drainage area = 18.990 ac Curve number = 73.5
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 2.94 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Post-Development Drainage Area #1
Q (cfs) Hyd. No. 4 -- 1 Year Q (cfs)
28.00 28.00
24.00 24.00
20.00 20.00
16.00 16.00
•
12.00 12.00
8.00 8.00
4.00 :::
0.00 — / -
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
— Hyd No. 4

8
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 5
Wetpond#1
Hydrograph type = Reservoir Peak discharge = 0.214 cfs
Storm frequency = 1 yrs Time to peak = 1444 min
Time interval = 2 min Hyd. volume = 46,837 cuft
Inflow hyd. No. = 4 - Post-Development Drainage/IAxeEI 1iation = 646.81 ft
Reservoir name = Wet Pond #1 Max. Storage = 45,967 cuft
Storage Indication method used.
Wetpond #1
Q (cfs) Hyd. No. 5-- 1 Year Q (cfs)
28.00 28.00
24.00 24.00
20.00 - - 20.00
16.00 16.00
12.00 12.00
8.00 8.00
4.00L -
4.00
0.00 - - 0.00
0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000
Time (min)
Hyd No. 5 Hyd No. 4 111111111 Total storage used = 45,967 cuft

9
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 6
Post-Development Drainage Area #2
Hydrograph type = SCS Runoff Peak discharge = 29.88 cfs
Storm frequency = 1 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 60,544 cuft
Drainage area = 22.070 ac Curve number = 72.7
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 2.94 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Post-Development Drainage Area #2
Q (cfs) Hyd. No. 6 -- 1 Year Q (cfs)
30.00 30.00
25.00 25.00
20.00 20.00
15.00 15.00
10.00 10.00
5.00 5.00
0.00 — 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 6 Time (min)

10
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 7
Wet Pond #2
Hydrograph type = Reservoir Peak discharge = 0.254 cfs
Storm frequency = 1 yrs Time to peak = 1442 min
Time interval = 2 min Hyd. volume = 52,380 cuft
Inflow hyd. No. = 6 - Post-Development Drainage/IAxeEV ?iation = 646.28 ft
Reservoir name = Wet Pond #2 Max. Storage = 50,325 cuft
Storage Indication method used.
Wet Pond #2
Q (cfs) Hyd. No. 7 -- 1 Year Q (cfs)
30.00 30.00
25.00 25.00
20.00 20.00
15.00 15.00
10.00 10.00
5.00 5.00
L
0.00 0.00
0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000
Time (min)
Hyd No. 7 Hyd No. 6 111111111 Total storage used = 50,325 cuft

11
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 8
Post-Development Discharge Rate
Hydrograph type = Combine Peak discharge = 0.469 cfs
Storm frequency = 1 yrs Time to peak = 1442 min
Time interval = 2 min Hyd. volume = 99,217 cuft
Inflow hyds. = 5, 7 Contrib. drain. area = 0.000 ac
Post-Development Discharge Rate
Q (cfs) Hyd. No. 8 -- 1 Year Q (cfs)
0.50 0.50
0.45 0.45
0.40 0.40
0.35 0.35
0.30 0.30
0.25 0.25
0.20 0.20
0.15 0.15
0.10 0.10
0.05 0.05
0.00 - 0.00
0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000
Time (min)
Hyd No. 8 Hyd No. 5 Hyd No. 7

12
Hydrograph Summary Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 5.391 2 750 44,924 Pre-Drainage Area#1
2 SCS Runoff 5.359 2 754 48,713 Pre-Drainage Area#2
3 Combine 10.73 2 752 93,637 1,2 Pre-Development Discharge Rate
4 SCS Runoff 39.96 2 718 79,935 Post-Development Drainage Area#1
5 Reservoir 0.260 2 1444 61,931 4 647.62 69,282 Wetpond#1
6 SCS Runoff 44.59 2 718 89,272 Post-Development Drainage Area#2
7 Reservoir 0.315 2 1444 71,759 6 646.91 76,463 Wet Pond#2
8 Combine 0.576 2 1444 133,689 5,7 Post-Development Discharge Rate
326256-Heritage at Marvin-Wetponds HydrogpRaltugpReriod: 2 Year Thursday, 11 / 16/2023

13
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 1
Pre-Drainage Area #1
Hydrograph type = SCS Runoff Peak discharge = 5.391 cfs
Storm frequency = 2 yrs Time to peak = 750 min
Time interval = 2 min Hyd. volume = 44,924 cuft
Drainage area = 18.990 ac Curve number = 62.5
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 55.30 min
Total precip. = 3.54 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Pre-Drainage Area #1
Q (cfs) Hyd. No. 1 -- 2 Year Q(cfs)
6.00 6.00
—
ILE
5.00 5.00
4.00 4.00
3.00 3.00
2.00 2.00
tootoo
__L.................._.__L
1
0.00 _. ., - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 1 Time (min)

14
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 2
Pre-Drainage Area #2
Hydrograph type = SCS Runoff Peak discharge = 5.359 cfs
Storm frequency = 2 yrs Time to peak = 754 min
Time interval = 2 min Hyd. volume = 48,713 cuft
Drainage area = 22.070 ac Curve number = 61.4
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 59.80 min
Total precip. = 3.54 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Pre-Drainage Area #2
Q (cfs) Hyd. No. 2 -- 2 Year Q(cfs)
6.00 6.00
5.00 5.00
4.00 4.00
3.00 3.00
2.00 2.00
1.00 1.00
0.00 - ` 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 2 Time (min)

15
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 3
Pre-Development Discharge Rate
Hydrograph type = Combine Peak discharge = 10.73 cfs
Storm frequency = 2 yrs Time to peak = 752 min
Time interval = 2 min Hyd. volume = 93,637 cuft
Inflow hyds. = 1, 2 Contrib. drain. area = 41.060 ac
Pre-Development Discharge Rate
Q (cfs) Hyd. No. 3 -- 2 Year Q (cfs)
12.00 12.00
10.00 - 10.00
8.00 8.00
6.00 - 6.00
4.00 4.00
2.00 - 2.00
0.00 ' 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 3 Hyd No. 1 Hyd No. 2

16
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 4
Post-Development Drainage Area #1
Hydrograph type = SCS Runoff Peak discharge = 39.96 cfs
Storm frequency = 2 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 79,935 cuft
Drainage area = 18.990 ac Curve number = 73.5
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 3.54 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Post-Development Drainage Area #1
Q (cfs) Hyd. No. 4 -- 2 Year Q (cfs)
40.00 - 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 — —. I I
1 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
— Hyd No. 4

17
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 5
Wetpond #1
Hydrograph type = Reservoir Peak discharge = 0.260 cfs
Storm frequency = 2 yrs Time to peak = 1444 min
Time interval = 2 min Hyd. volume = 61,931 cuft
Inflow hyd. No. = 4 - Post-Development DrainagellAxeEltliation = 647.62 ft
Reservoir name = Wet Pond #1 Max. Storage = 69,282 cuft
Storage Indication method used.
Wetpond #1
Q (cfs) Hyd. No. 5 -- 2 Year Q (cfs)
40.00 40.00
30.00 - 30.00
20.00 20.00
10.00 - 10.00
0.00 0.00
0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000
Time (min)
— Hyd No. 5 Hyd No. 4 TTTTT1 II Total storage used = 69,282 cuft

18
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 6
Post-Development Drainage Area #2
Hydrograph type = SCS Runoff Peak discharge = 44.59 cfs
Storm frequency = 2 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 89,272 cuft
Drainage area = 22.070 ac Curve number = 72.7
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 3.54 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Post-Development Drainage Area #2
Q (cfs) Hyd. No. 6 -- 2 Year Q (cfs)
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 — _ _ _ ' ' 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
— Hyd No. 6

19
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 7
Wet Pond #2
Hydrograph type = Reservoir Peak discharge = 0.315 cfs
Storm frequency = 2 yrs Time to peak = 1444 min
Time interval = 2 min Hyd. volume = 71,759 cuft
Inflow hyd. No. = 6 - Post-Development DrainagW/lAxeEI 2'ation = 646.91 ft
Reservoir name = Wet Pond #2 Max. Storage = 76,463 cuft
Storage Indication method used.
Wet Pond #2
Q (cfs) Hyd. No. 7 -- 2 Year Q (cfs)
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 0.00
0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000
Time (min)
— Hyd No. 7 Hyd No. 6 TTTTT1 II Total storage used = 76,463 cuft

20
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 8
Post-Development Discharge Rate
Hydrograph type = Combine Peak discharge = 0.576 cfs
Storm frequency = 2 yrs Time to peak = 1444 min
Time interval = 2 min Hyd. volume = 133,689 cuft
Inflow hyds. = 5, 7 Contrib. drain. area = 0.000 ac
Post-Development Discharge Rate
Q (cfs) Hyd. No. 8 -- 2 Year Q (cfs)
1.00 - 1.00
0.90 I 0.90
0.80 0.80
0.70 0.70
0.60 0.60
0.50 0.50
0.40 - 0.40
0.30 0.30
0.20 0.20
0.10 0.10
0.00 0.00
0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000
Time (min)
Hyd No. 8 Hyd No. 5 Hyd No. 7

21
Hydrograph Summary Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 10.82 2 750 78,135 Pre-Drainage Area#1
2 SCS Runoff 11.09 2 752 86,147 Pre-Drainage Area#2
3 Combine 21.85 2 750 164,282 1,2 Pre-Development Discharge Rate
4 SCS Runoff 61.08 2 718 122,519 Post-Development Drainage Area#1
5 Reservoir 1.792 2 888 98,442 4 648.07 82,631 Wetpond#1
6 SCS Runoff 68.81 2 718 137,862 Post-Development Drainage Area#2
7 Reservoir 0.395 2 1444 97,263 6 647.93 121,582 Wet Pond#2
8 Combine 2.146 2 890 195,704 5,7 Post-Development Discharge Rate
326256-Heritage at Marvin-Wetponds HydrogpRaltugpReriod: 5 Year Thursday, 11 / 16/2023

22
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 1
Pre-Drainage Area #1
Hydrograph type = SCS Runoff Peak discharge = 10.82 cfs
Storm frequency = 5 yrs Time to peak = 750 min
Time interval = 2 min Hyd. volume = 78,135 cuft
Drainage area = 18.990 ac Curve number = 62.5
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 55.30 min
Total precip. = 4.45 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Pre-Drainage Area #1
Q (cfs) Hyd. No. 1 -- 5 Year Q (cfs)
12.00 12.00
10.00 - 10.00
8.00 - 8.00
6.00 - 6.00
4.00 4.00
2.00 2.00
0.00 - N._- 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 1 Time (min)

23
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 2
Pre-Drainage Area #2
Hydrograph type = SCS Runoff Peak discharge = 11.09 cfs
Storm frequency = 5 yrs Time to peak = 752 min
Time interval = 2 min Hyd. volume = 86,147 cuft
Drainage area = 22.070 ac Curve number = 61.4
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 59.80 min
Total precip. = 4.45 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Pre-Drainage Area #2
Q (cfs) Hyd. No. 2 -- 5 Year Q (cfs)
12.00 12.00
4
10.00 - 10.00
8.00 8.00
6.00 - 6.00
4.00 4.00
2.00 2.00
0.00 - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 2 Time (min)

24
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 3
Pre-Development Discharge Rate
Hydrograph type = Combine Peak discharge = 21.85 cfs
Storm frequency = 5 yrs Time to peak = 750 min
Time interval = 2 min Hyd. volume = 164,282 cuft
Inflow hyds. = 1, 2 Contrib. drain. area = 41.060 ac
Pre-Development Discharge Rate
Q (cfs) Hyd. No. 3 -- 5 Year Q (cfs)
24.00 24.00
20.00 20.00
16.00 16.00
12.00 12.00
8.00 8.00
4.00 4.00
0.00 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 3 Hyd No. 1 Hyd No. 2

25
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 4
Post-Development Drainage Area #1
Hydrograph type = SCS Runoff Peak discharge = 61.08 cfs
Storm frequency = 5 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 122,519 cuft
Drainage area = 18.990 ac Curve number = 73.5
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 4.45 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Post-Development Drainage Area #1
Q (cfs) Hyd. No. 4 -- 5 Year Q (cfs)
70.00 70.00
60.00 60.00
50.00 — 50.00
I
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
s
0.00 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 4 Time (min)

26
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 5
Wetpond #1
Hydrograph type = Reservoir Peak discharge = 1.792 cfs
Storm frequency = 5 yrs Time to peak = 888 min
Time interval = 2 min Hyd. volume = 98,442 cuft
Inflow hyd. No. = 4 - Post-Development Drainage/IAxeEI 1iation = 648.07 ft
Reservoir name = Wet Pond #1 Max. Storage = 82,631 cuft
Storage Indication method used.
Wetpond #1
Q (cfs) Hyd. No. 5-- 5 Year Q (cfs)
70.00 70.00
60.00 60.00
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 0.00
0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000
Time (min)
Hyd No. 5 Hyd No. 4 111111111 Total storage used = 82,631 cuft

27
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 6
Post-Development Drainage Area #2
Hydrograph type = SCS Runoff Peak discharge = 68.81 cfs
Storm frequency = 5 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 137,862 cuft
Drainage area = 22.070 ac Curve number = 72.7
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 4.45 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Post-Development Drainage Area #2
Q (cfs) Hyd. No. 6 -- 5 Year Q (cfs)
70.00 70.00
60.00 60.00
50.00 50.00
40.00 •
40.00
30.00 30.00
20.00 20.00
10.00 I 10.00
H s
0.00 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 6 Time (min)

28
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 7
Wet Pond #2
Hydrograph type = Reservoir Peak discharge = 0.395 cfs
Storm frequency = 5 yrs Time to peak = 1444 min
Time interval = 2 min Hyd. volume = 97,263 cuft
Inflow hyd. No. = 6 - Post-Development Drainage/IAxeEV ?iation = 647.93 ft
Reservoir name = Wet Pond #2 Max. Storage = 121,582 cuft
Storage Indication method used.
Wet Pond #2
Q (cfs) Hyd. No. 7 -- 5 Year Q (cfs)
70.00 70.00
60.00 60.00
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 0.00
0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000
Time (min)
Hyd No. 7 Hyd No. 6 111111111 Total storage used = 121,582 cuft

29
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 8
Post-Development Discharge Rate
Hydrograph type = Combine Peak discharge = 2.146 cfs
Storm frequency = 5 yrs Time to peak = 890 min
Time interval = 2 min Hyd. volume = 195,704 cuft
Inflow hyds. = 5, 7 Contrib. drain. area = 0.000 ac
Post-Development Discharge Rate
Q (cfs) Hyd. No. 8 -- 5 Year Q (cfs)
3.00 3.00
2.00 - 2.00
1.00 1.00
11111
111.11
0.00 - 0.00
0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000
Time (min)
Hyd No. 8 Hyd No. 5 Hyd No. 7

30
Hydrograph Summary Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 15.88 2 748 108,171 Pre-Drainage Area#1
2 SCS Runoff 16.54 2 752 120,250 Pre-Drainage Area#2
3 Combine 32.39 2 750 228,421 1,2 Pre-Development Discharge Rate
4 SCS Runoff 78.66 2 716 158,811 Post-Development Drainage Area#1
5 Reservoir 5.699 2 756 134,686 4 648.19 86,223 Wetpond#1
6 SCS Runoff 89.04 2 718 179,424 Post-Development Drainage Area#2
7 Reservoir 2.125 2 936 136,467 6 648.08 128,755 Wet Pond#2
8 Combine 6.063 2 756 271,152 5,7 Post-Development Discharge Rate
326256-Heritage at Marvin-Wetponds HydrogpRaltugpReriod: 10 Year Thursday, 11 / 16/2023

31
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 1
Pre-Drainage Area #1
Hydrograph type = SCS Runoff Peak discharge = 15.88 cfs
Storm frequency = 10 yrs Time to peak = 748 min
Time interval = 2 min Hyd. volume = 108,171 cuft
Drainage area = 18.990 ac Curve number = 62.5
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 55.30 min
Total precip. = 5.17 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Pre-Drainage Area #1
Q (cfs) Hyd. No. 1 -- 10 Year Q (cfs)
18.00 18.00
1
15.00 15.00
12.00 12.00
9.00 9.00
6.00 6.00
j \ .................... —...........,..-
3.00 3.00
0.00 - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 1 Time (min)

32
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 2
Pre-Drainage Area #2
Hydrograph type = SCS Runoff Peak discharge = 16.54 cfs
Storm frequency = 10 yrs Time to peak = 752 min
Time interval = 2 min Hyd. volume = 120,250 cuft
Drainage area = 22.070 ac Curve number = 61.4
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 59.80 min
Total precip. = 5.17 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Pre-Drainage Area #2
Q (cfs) Hyd. No. 2 -- 10 Year Q (cfs)
18.00 18.00
r
15.00 15.00
12.00 12.00
9.00 9.00
6.00 6.00
3.00 3.00
__jA,. ................,..,............
0.00 - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 2 Time (min)

33
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 3
Pre-Development Discharge Rate
Hydrograph type = Combine Peak discharge = 32.39 cfs
Storm frequency = 10 yrs Time to peak = 750 min
Time interval = 2 min Hyd. volume = 228,421 cuft
Inflow hyds. = 1, 2 Contrib. drain. area = 41.060 ac
Pre-Development Discharge Rate
Q (cfs) Hyd. No. 3 -- 10 Year Q (cfs)
35.00 35.00
30.00 30.00
25.00 25.00
20.00 20.00
15.00 15.00
10.00 10.00
5.00 5.00
0.00 - ^ 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 3 Hyd No. 1 Hyd No. 2

34
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 4
Post-Development Drainage Area #1
Hydrograph type = SCS Runoff Peak discharge = 78.66 cfs
Storm frequency = 10 yrs Time to peak = 716 min
Time interval = 2 min Hyd. volume = 158,811 cuft
Drainage area = 18.990 ac Curve number = 73.5
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 5.17 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Post-Development Drainage Area #1
Q (cfs) Hyd. No. 4 -- 10 Year Q (cfs)
80.00 , 80.00
70.00 70.00
60.00 60.00
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 � 1 I — 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 4 Time (min)

35
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 5
Wetpond #1
Hydrograph type = Reservoir Peak discharge = 5.699 cfs
Storm frequency = 10 yrs Time to peak = 756 min
Time interval = 2 min Hyd. volume = 134,686 cuft
Inflow hyd. No. = 4 - Post-Development Drainage/IAxeEI 1iation = 648.19 ft
Reservoir name = Wet Pond #1 Max. Storage = 86,223 cuft
Storage Indication method used.
Wetpond #1
Q (cfs) Hyd. No. 5-- 10 Year Q (cfs)
80.00 80.00
70.00 70.00
60.00 60.00
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 0.00
0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000
Time (min)
Hyd No. 5 Hyd No. 4 111111111 Total storage used = 86,223 cuft

36
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 6
Post-Development Drainage Area #2
Hydrograph type = SCS Runoff Peak discharge = 89.04 cfs
Storm frequency = 10 yrs Time to peak = 718 min
Time interval = 2 min Hyd. volume = 179,424 cuft
Drainage area = 22.070 ac Curve number = 72.7
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 5.17 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Post-Development Drainage Area #2
Q (cfs) Hyd. No. 6 -- 10 Year Q (cfs)
90.00 90.00
80.00 80.00
70.00 70.00
60.00 60.00
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 A — 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 6 Time (min)

37
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 7
Wet Pond #2
Hydrograph type = Reservoir Peak discharge = 2.125 cfs
Storm frequency = 10 yrs Time to peak = 936 min
Time interval = 2 min Hyd. volume = 136,467 cuft
Inflow hyd. No. = 6 - Post-Development Drainage/IAxeEV ?iation = 648.08 ft
Reservoir name = Wet Pond #2 Max. Storage = 128,755 cuft
Storage Indication method used.
Wet Pond #2
Q (cfs) Hyd. No. 7 -- 10 Year Q (cfs)
90.00 90.00
80.00 80.00
70.00 70.00
60.00 60.00
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 L - 10.00
0.00 0.00
0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000
Time (min)
Hyd No. 7 Hyd No. 6 111111111 Total storage used = 128,755 cuft

38
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 8
Post-Development Discharge Rate
Hydrograph type = Combine Peak discharge = 6.063 cfs
Storm frequency = 10 yrs Time to peak = 756 min
Time interval = 2 min Hyd. volume = 271,152 cuft
Inflow hyds. = 5, 7 Contrib. drain. area = 0.000 ac
Post-Development Discharge Rate
Q (cfs) Hyd. No. 8 -- 10 Year Q (cfs)
7.00 7.00
6.00 6.00
5.00 5.00
4.00 4.00
3.00 3.00
2.00 2.00
1.00 — - 1.00
Nmmmmy
0.00 0.00
0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000
Time (min)
Hyd No. 8 Hyd No. 5 Hyd No. 7

39
Hydrograph Summary Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 23.51 2 748 153,117 Pre-Drainage Area#1
2 SCS Runoff 24.84 2 750 171,548 Pre-Drainage Area#2
3 Combine 48.25 2 750 324,665 1,2 Pre-Development Discharge Rate
4 SCS Runoff 104.20 2 716 210,830 Post-Development Drainage Area#1
5 Reservoir 27.07 2 724 186,653 4 648.54 97,482 Wetpond#1
6 SCS Runoff 118.31 2 716 239,158 Post-Development Drainage Area#2
7 Reservoir 7.571 2 764 196,082 6 648.22 135,469 Wet Pond#2
8 Combine 27.46 2 724 382,733 5,7 Post-Development Discharge Rate
326256-Heritage at Marvin-Wetponds HydrogpRaltugpReriod: 25 Year Thursday, 11 / 16/2023

40
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 1
Pre-Drainage Area #1
Hydrograph type = SCS Runoff Peak discharge = 23.51 cfs
Storm frequency = 25 yrs Time to peak = 748 min
Time interval = 2 min Hyd. volume = 153,117 cuft
Drainage area = 18.990 ac Curve number = 62.5
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 55.30 min
Total precip. = 6.15 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Pre-Drainage Area #1
Q (cfs) Hyd. No. 1 -- 25 Year Q (cfs)
24.00 24.00
$
20.00 20.00
16.00 16.00
12.00 12.00
8.00 8.00
4.00 :::
0.00 J
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 1 Time (min)

41
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 2
Pre-Drainage Area #2
Hydrograph type = SCS Runoff Peak discharge = 24.84 cfs
Storm frequency = 25 yrs Time to peak = 750 min
Time interval = 2 min Hyd. volume = 171,548 cuft
Drainage area = 22.070 ac Curve number = 61.4
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 59.80 min
Total precip. = 6.15 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Pre-Drainage Area #2
Q (cfs) Hyd. No. 2 -- 25 Year Q (cfs)
28.00 28.00
24.00 A 24.00
20.00 20.00
I \
16.00 16.00
12.00 12.00
8.00 8.00
4.00 4.00
0.00 — 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 2 Time (min)

42
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 3
Pre-Development Discharge Rate
Hydrograph type = Combine Peak discharge = 48.25 cfs
Storm frequency = 25 yrs Time to peak = 750 min
Time interval = 2 min Hyd. volume = 324,665 cuft
Inflow hyds. = 1, 2 Contrib. drain. area = 41.060 ac
Pre-Development Discharge Rate
Q (cfs) Hyd. No. 3 -- 25 Year Q (cfs)
50.00 50.00
1-
40.00 40.00
30.00 30.00
T
I
20.00 20.00
Viieaim ................
10.00 10.00
0.00 — 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 3 Hyd No. 1 Hyd No. 2

43
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 4
Post-Development Drainage Area #1
Hydrograph type = SCS Runoff Peak discharge = 104.20 cfs
Storm frequency = 25 yrs Time to peak = 716 min
Time interval = 2 min Hyd. volume = 210,830 cuft
Drainage area = 18.990 ac Curve number = 73.5
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 6.15 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Post-Development Drainage Area #1
Q (cfs) Hyd. No. 4 -- 25 Year Q (cfs)
120.00 120.00
100.00 100.00
80.00 80.00
60.00 60.00
40.00 40.00
20.00 20.00
0.00 — 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440
Hyd No. 4 Time (min)

44
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 5
Wetpond #1
Hydrograph type = Reservoir Peak discharge = 27.07 cfs
Storm frequency = 25 yrs Time to peak = 724 min
Time interval = 2 min Hyd. volume = 186,653 cuft
Inflow hyd. No. = 4 - Post-Development Drainage/IAxeEI 1iation = 648.54 ft
Reservoir name = Wet Pond #1 Max. Storage = 97,482 cuft
Storage Indication method used.
Wetpond #1
Q (cfs) Hyd. No. 5-- 25 Year Q (cfs)
120.00 120.00
100.00 100.00
80.00 80.00
60.00 60.00
40.00 40.00
20.00 20.00
0.00 ► 0.00
0 240 480 720 960 1200 1440 1680 1920
Time (min)
Hyd No. 5 Hyd No. 4 111111111 Total storage used = 97,482 cuft

45
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 6
Post-Development Drainage Area #2
Hydrograph type = SCS Runoff Peak discharge = 118.31 cfs
Storm frequency = 25 yrs Time to peak = 716 min
Time interval = 2 min Hyd. volume = 239,158 cuft
Drainage area = 22.070 ac Curve number = 72.7
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 6.15 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Post-Development Drainage Area #2
Q (cfs) Hyd. No. 6 -- 25 Year Q (cfs)
120.00 120.00
100.00 100.00
80.00 80.00
60.00 60.00
40.00 40.00
20.00 20.00
J
0.00 — ' 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440
Hyd No. 6 Time (min)

46
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 7
Wet Pond #2
Hydrograph type = Reservoir Peak discharge = 7.571 cfs
Storm frequency = 25 yrs Time to peak = 764 min
Time interval = 2 min Hyd. volume = 196,082 cuft
Inflow hyd. No. = 6 - Post-Development Drainage/IAxeEV ?iation = 648.22 ft
Reservoir name = Wet Pond #2 Max. Storage = 135,469 cuft
Storage Indication method used.
Wet Pond #2
Q (cfs) Hyd. No. 7 -- 25 Year Q (cfs)
120.00 120.00
100.00 100.00
80.00 80.00
60.00 60.00
40.00 40.00
20.00 20.00
l'''
0.00 0.00
0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000
Time (min)
Hyd No. 7 Hyd No. 6 111111111 Total storage used = 135,469 cuft

47
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 8
Post-Development Discharge Rate
Hydrograph type = Combine Peak discharge = 27.46 cfs
Storm frequency = 25 yrs Time to peak = 724 min
Time interval = 2 min Hyd. volume = 382,733 cuft
Inflow hyds. = 5, 7 Contrib. drain. area = 0.000 ac
Post-Development Discharge Rate
Q (cfs) Hyd. No. 8 -- 25 Year Q (cfs)
28.00 28.00
24.00 24.00
20.00 20.00
16.00 16.00
12.00 12.00
8.00 8.00
4.00 \ 4.00
0.00 - 0.00
0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000
Time (min)
Hyd No. 8 Hyd No. 5 Hyd No. 7

48
Hydrograph Summary Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 30.09 2 748 192,036 Pre-Drainage Area#1
2 SCS Runoff 32.05 2 750 216,145 Pre-Drainage Area#2
3 Combine 61.96 2 750 408,180 1,2 Pre-Development Discharge Rate
4 SCS Runoff 125.26 2 716 254,406 Post-Development Drainage Area#1
5 Reservoir 53.43 2 722 230,195 4 648.93 109,670 Wetpond#1
6 SCS Runoff 142.65 2 716 289,301 Post-Development Drainage Area#2
7 Reservoir 18.80 2 732 246,146 6 648.42 144,850 Wet Pond#2
8 Combine 68.51 2 724 476,340 5,7 Post-Development Discharge Rate
326256-Heritage at Marvin-Wetponds HydrogpRaltugpReriod: 50 Year Thursday, 11 / 16/2023

49
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 1
Pre-Drainage Area #1
Hydrograph type = SCS Runoff Peak discharge = 30.09 cfs
Storm frequency = 50 yrs Time to peak = 748 min
Time interval = 2 min Hyd. volume = 192,036 cuft
Drainage area = 18.990 ac Curve number = 62.5
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 55.30 min
Total precip. = 6.94 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Pre-Drainage Area #1
Q (cfs) Hyd. No. 1 -- 50 Year Q (cfs)
35.00 35.00
30.00 _ t 30.00
25.00 25.00
20.00 20.00
15.00 15.00
10.00 10.00
\ *41"••••,....,..............
5.00 5.00
0.00 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 1 Time (min)

50
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 2
Pre-Drainage Area #2
Hydrograph type = SCS Runoff Peak discharge = 32.05 cfs
Storm frequency = 50 yrs Time to peak = 750 min
Time interval = 2 min Hyd. volume = 216,145 cuft
Drainage area = 22.070 ac Curve number = 61.4
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 59.80 min
Total precip. = 6.94 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Pre-Drainage Area #2
Q (cfs) Hyd. No. 2 -- 50 Year Q (cfs)
35.00 35.00
I-
30.00 30.00
25.00 25.00
20.00 20.00
1 -\
15.00 15.00
10.00 10.00
5.00 5.00
0.00 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Hyd No. 2 Time (min)

51
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 3
Pre-Development Discharge Rate
Hydrograph type = Combine Peak discharge = 61.96 cfs
Storm frequency = 50 yrs Time to peak = 750 min
Time interval = 2 min Hyd. volume = 408,180 cuft
Inflow hyds. = 1, 2 Contrib. drain. area = 41.060 ac
Pre-Development Discharge Rate
Q (cfs) Hyd. No. 3 -- 50 Year Q (cfs)
70.00 70.00
60.00 p 60.00
50.00 50.00
40.00 40.00
30.00 � 30.00
20.00 20.00
10.00 10.00
0.00 - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 3 Hyd No. 1 Hyd No. 2

52
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 4
Post-Development Drainage Area #1
Hydrograph type = SCS Runoff Peak discharge = 125.26 cfs
Storm frequency = 50 yrs Time to peak = 716 min
Time interval = 2 min Hyd. volume = 254,406 cuft
Drainage area = 18.990 ac Curve number = 73.5
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 6.94 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Post-Development Drainage Area #1
Q (cfs) Hyd. No. 4 -- 50 Year Q (cfs)
140.00 I I 140.00
120.00 I 120.00
100.00 100.00
80.00 - 80.00
60.00 60.00
40.00 40.00
20.00 20.00
0.00 - ' 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440
Hyd No. 4 Time (min)

53
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 5
Wetpond #1
Hydrograph type = Reservoir Peak discharge = 53.43 cfs
Storm frequency = 50 yrs Time to peak = 722 min
Time interval = 2 min Hyd. volume = 230,195 cuft
Inflow hyd. No. = 4 - Post-Development Drainage/IAxeEI 1iation = 648.93 ft
Reservoir name = Wet Pond #1 Max. Storage = 109,670 cuft
Storage Indication method used.
Wetpond #1
Q (cfs) Hyd. No. 5-- 50 Year Q (cfs)
140.00 140.00
120.00 120.00
100.00 100.00
80.00 80.00
60.00 60.00
40.00 40.00
20.00 20.00
7_7
0.00 ......... 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 5 Hyd No. 4 111111111 Total storage used = 109,670 cuft

54
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 6
Post-Development Drainage Area #2
Hydrograph type = SCS Runoff Peak discharge = 142.65 cfs
Storm frequency = 50 yrs Time to peak = 716 min
Time interval = 2 min Hyd. volume = 289,301 cuft
Drainage area = 22.070 ac Curve number = 72.7
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 6.94 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Post-Development Drainage Area #2
Q (cfs) Hyd. No. 6 -- 50 Year Q (cfs)
160.00 i 160.00
140.00 I
140.00
120.00 120.00
I
100.00 100.00
80.00 80.00
60.00 60.00
40.00 II _ 40.00
20.00 20.00
0.00 — 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440
Hyd No. 6 Time (min)

55
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 7
Wet Pond #2
Hydrograph type = Reservoir Peak discharge = 18.80 cfs
Storm frequency = 50 yrs Time to peak = 732 min
Time interval = 2 min Hyd. volume = 246,146 cuft
Inflow hyd. No. = 6 - Post-Development Drainage/IAxeEV ?iation = 648.42 ft
Reservoir name = Wet Pond #2 Max. Storage = 144,850 cuft
Storage Indication method used.
Wet Pond #2
Q (cfs) Hyd. No. 7 -- 50 Year Q (cfs)
160.00 160.00
140.00 140.00
120.00 120.00
100.00 100.00
80.00 80.00
60.00 60.00
40.00 40.00
20.00 20.00
0.00 0.00
0 600 1200 1800 2400 3000 3600 4200 4800 5400 6000
Time (min)
Hyd No. 7 Hyd No. 6 111111111 Total storage used = 144,850 cuft

56
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 8
Post-Development Discharge Rate
Hydrograph type = Combine Peak discharge = 68.51 cfs
Storm frequency = 50 yrs Time to peak = 724 min
Time interval = 2 min Hyd. volume = 476,340 cuft
Inflow hyds. = 5, 7 Contrib. drain. area = 0.000 ac
Post-Development Discharge Rate
Q (cfs) Hyd. No. 8 -- 50 Year Q (cfs)
70.00 70.00
60.00 60.00
50.00 50.00
40.00 I 40.00
30.00 30.00
20.00 20.00
10.00 10.00
0.00 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 8 Hyd No. 5 Hyd No. 7

57
Hydrograph Summary Report Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024
Hyd. Hydrograph Peak Time Time to Hyd. Inflow Maximum Total Hydrograph
No. type flow interval Peak volume hyd(s) elevation strge used Description
(origin) (cfs) (min) (min) (cuft) (ft) (cuft)
1 SCS Runoff 37.24 2 748 234,447 Pre-Drainage Area#1
2 SCS Runoff 39.90 2 750 264,878 Pre-Drainage Area#2
3 Combine 76.86 2 750 499,325 1,2 Pre-Development Discharge Rate
4 SCS Runoff 147.40 2 716 300,812 Post-Development Drainage Area#1
5 Reservoir 69.48 2 722 276,569 4 649.38 124,758 Wetpond#1
6 SCS Runoff 168.27 2 716 342,775 Post-Development Drainage Area#2
7 Reservoir 48.16 2 724 299,549 6 648.80 162,733 Wet Pond#2
8 Combine 115.50 2 724 576,118 5,7 Post-Development Discharge Rate
326256-Heritage at Marvin-Wetponds HydrogpRaltugpReriod: 100 Year Thursday, 11 / 16/2023

58
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 1
Pre-Drainage Area #1
Hydrograph type = SCS Runoff Peak discharge = 37.24 cfs
Storm frequency = 100 yrs Time to peak = 748 min
Time interval = 2 min Hyd. volume = 234,447 cuft
Drainage area = 18.990 ac Curve number = 62.5
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 55.30 min
Total precip. = 7.76 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Pre-Drainage Area #1
Q (cfs) Hyd. No. 1 -- 100 Year Q (cfs)
40.00 40.00
1\
30.00 30.00
20.00 20.00
j 4"1`..........................
10.00 10.00
0.00 — - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
— Hyd No. 1

59
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 2
Pre-Drainage Area #2
Hydrograph type = SCS Runoff Peak discharge = 39.90 cfs
Storm frequency = 100 yrs Time to peak = 750 min
Time interval = 2 min Hyd. volume = 264,878 cuft
Drainage area = 22.070 ac Curve number = 61.4
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = TR55 Time of conc. (Tc) = 59.80 min
Total precip. = 7.76 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Pre-Drainage Area #2
Q (cfs) Hyd. No. 2 -- 100 Year Q (cfs)
40.00 , $ 40.00
30.00 30.00
20.00 20.00
10.00 10.00
\ %*%.....,........................
0.00 - .......2 I I
-- 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
— Hyd No. 2

60
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 3
Pre-Development Discharge Rate
Hydrograph type = Combine Peak discharge = 76.86 cfs
Storm frequency = 100 yrs Time to peak = 750 min
Time interval = 2 min Hyd. volume = 499,325 cuft
Inflow hyds. = 1, 2 Contrib. drain. area = 41.060 ac
Pre-Development Discharge Rate
Q (cfs) Hyd. No. 3 -- 100 Year Q (cfs)
80.00 80.00
70.00 70.00
60.00 60.00
50.00 50.00
40.00 40.00
30.00 30.00
20.00 20.00
10.00 ` 10.00
0.00 - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 3 Hyd No. 1 Hyd No. 2

61
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 4
Post-Development Drainage Area #1
Hydrograph type = SCS Runoff Peak discharge = 147.40 cfs
Storm frequency = 100 yrs Time to peak = 716 min
Time interval = 2 min Hyd. volume = 300,812 cuft
Drainage area = 18.990 ac Curve number = 73.5
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 7.76 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Post-Development Drainage Area #1
Q (cfs) Hyd. No. 4 -- 100 Year Q (cfs)
160.00 i 160.00
140.00 I
140.00
120.00 I 120.00
I
100.00 100.00
80.00 80.00
60.00 60.00
40.00 II _ 40.00
20.00 20.00
0.00 — ' 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440
Hyd No. 4 Time (min)

62
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 5
Wetpond #1
Hydrograph type = Reservoir Peak discharge = 69.48 cfs
Storm frequency = 100 yrs Time to peak = 722 min
Time interval = 2 min Hyd. volume = 276,569 cuft
Inflow hyd. No. = 4 - Post-Development Drainage/IAxeEltliation = 649.38 ft
Reservoir name = Wet Pond #1 Max. Storage = 124,758 cuft
Storage Indication method used.
Wetpond #1
Q (cfs) Hyd. No. 5 -- 100 Year Q (cfs)
160.00 160.00
140.00 140.00
120.00 120.00
100.00 � 100.00
80.00 80.00
60.00 60.00
i —
40.00 40.00
1
20.00 11 20.00
1M\
1
0.00 - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 5 Hyd No. 4 111111111 Total storage used = 124,758 cuft

63
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 6
Post-Development Drainage Area #2
Hydrograph type = SCS Runoff Peak discharge = 168.27 cfs
Storm frequency = 100 yrs Time to peak = 716 min
Time interval = 2 min Hyd. volume = 342,775 cuft
Drainage area = 22.070 ac Curve number = 72.7
Basin Slope = 0.0 % Hydraulic length = 0 ft
Tc method = User Time of conc. (Tc) = 5.00 min
Total precip. = 7.76 in Distribution = Type II
Storm duration = 24 hrs Shape factor = 484
Post-Development Drainage Area #2
Q (cfs) Hyd. No. 6 -- 100 Year Q (cfs)
180.00 180.00
160.00 160.00
140.00 140.00
120.00 120.00
100.00 100.00
80.00 80.00
60.00 60.00
40.00 40.00
20.00 20.00
0.00 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440
Hyd No. 6 Time (min)

64
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 7
Wet Pond #2
Hydrograph type = Reservoir Peak discharge = 48.16 cfs
Storm frequency = 100 yrs Time to peak = 724 min
Time interval = 2 min Hyd. volume = 299,549 cuft
Inflow hyd. No. = 6 - Post-Development Drainage/IAxeEV ?iation = 648.80 ft
Reservoir name = Wet Pond #2 Max. Storage = 162,733 cuft
Storage Indication method used.
Wet Pond #2
Q (cfs) Hyd. No. 7 -- 100 Year Q (cfs)
180.00 180.00
160.00 160.00
140.00 140.00
120.00 120.00
100.00 100.00
80.00 80.00
60.00 60.00
40.00 40.00
20.007 20.00
0.00 - — - 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 7 Hyd No. 6 111111111 Total storage used = 162,733 cuft

65
Hydrograph Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Hyd. No. 8
Post-Development Discharge Rate
Hydrograph type = Combine Peak discharge = 115.50 cfs
Storm frequency = 100 yrs Time to peak = 724 min
Time interval = 2 min Hyd. volume = 576,118 cuft
Inflow hyds. = 5, 7 Contrib. drain. area = 0.000 ac
Post-Development Discharge Rate
Q (cfs) Hyd. No. 8 -- 100 Year Q (cfs)
120.00 - - 120.00
100.00 ( 100.00
80.00 80.00
60.00 60.00
40.00 40.00
20.00 20.00
0.00 — 41o, 0.00
0 120 240 360 480 600 720 840 960 1080 1200 1320 1440 1560
Time (min)
Hyd No. 8 Hyd No. 5 Hyd No. 7

66
Hydraflow Rainfall Report
Hydraflow Hydrographs Extension for Autodesk®Civil 3D®by Autodesk, Inc.v2024 Thursday, 11 /16/2023
Return Intensity-Duration-Frequency Equation Coefficients(FHA)
Period
(Yrs) B D E (N/A)
1 64.9063 12.8000 0.8915
2 76.4669 13.1000 0.8855
3 0.0000 0.0000 0.0000
5 77.9987 13.0000 0.8425
10 71.3089 12.0000 0.7930
25 65.5456 11.1000 0.7420
50 59.2143 10.2000 0.6977
100 53.1435 9.1000 0.6547
File name:326256-Heritage at Marvin IDF Curve.IDF
Intensity= B/(Tc+ D)^E
Return Intensity Values(in/hr)
Period
(Yrs) 5 min 10 15 20 25 30 35 40 45 50 55 60
1 4.98 4.00 3.35 2.89 2.55 2.28 2.07 1.89 1.74 1.62 1.51 1.42
2 5.89 4.74 3.99 3.45 3.04 2.73 2.48 2.27 2.10 1.95 1.82 1.71
3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
5 6.83 5.56 4.71 4.10 3.64 3.28 2.99 2.75 2.55 2.38 2.23 2.10
10 7.54 6.15 5.22 4.57 4.07 3.68 3.37 3.11 2.89 2.70 2.54 2.40
25 8.34 6.82 5.83 5.12 4.58 4.16 3.82 3.54 3.30 3.10 2.92 2.77
50 8.87 7.27 6.23 5.49 4.94 4.50 4.15 3.85 3.61 3.40 3.21 3.05
100 9.40 7.70 6.62 5.85 5.27 4.82 4.45 4.15 3.90 3.68 3.49 3.32
Tc=time in minutes.Values may exceed 60.
Precip.file name:Sample.pcp
Rainfall Precipitation Table (in)
Storm
Distribution 1-yr 2-yr 3-yr 5-yr 10-yr 25-yr 50-yr 100-yr
SCS 24-hour 2.94 3.54 0.00 4.45 5.17 6.15 6.94 7.76
SCS 6-Hr 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Huff-1st 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Huff-2nd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Huff-3rd 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Huff-4th 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Huff-Indy 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Custom 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

STORM PIPING SYSTEM CALCULATIONS

0 I\ N
N
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GI-113 ;� . ii 1'��_,UH. ////�// ) 4 ) , /// / /iAlt:�.I- �'��,, 1, //%
.f � G`►1, 1// ; I, 'r/��A. //4/// \. \ //// A., i " /� �/y
44 .,�'' t , / j'��'� _ //� \ // j CI-401 x`2 o`er ' -
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® C -108 ;i;� � �/ \ ems'%'� -
� �./ � /\' //,i i/ ll,J J// ail I \ \ � CI-405 � � r
7/ .
// CI-402
'/ 1 r GI-110 /// //([ 1/// \ I III (( �1, /y)`j
o -/ •II ( /����//)1 I GI-109 DCI-409 \I�!i�� �., ,/I/i i
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o I �iC�j//�j / 41) )
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i \ / I \;i ...___ , i /
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ir, / 1 — I,
•
3 i \ .
o HERITAGE AT MARVIN
`, SCALE IN FEET ,-Fr/
SINGLE-FAMILY SUBDIVISION
Civil & Environmental Consultants, Inc.
JCH NC, LLC
0 200 400MARVIN, NORTH CAROLINA
qz,h 3701 Arco Corporate Drive•Suite 400•Charlotte,NC 28273
'' Ph:980.237.0373•Fax:[phone] INLET DRAINAGE AREA MAP
REFERENCE www.cecinc.com
o
1. TOPOGRAPHICAL SURVEY PERFORMED BY LAND SURVEYING, DRAWN BY: ERR CHECKED BY: CAP APPROVED BY: MLG FIGURE NO.:
tn INC.; DATE JANUARY 19, 2022 DATE: NOVEMBER 2023 DWG SCALE: 1"=200' PROJECT NO: 326-256 HYD-5
k

Hydraflow Storm Sewers Extension for Autodesk® Civil 3D® Plan
6
5
14 4
3
2 1 Outfall
13
8
12
9
11
10
Project File: BMP-100.stm Number of lines: 14 Date: 11/16/2023
Storm Sewers v2024.00

Storm Sewer Tabulation Pagel
Station Len Drng Area Rnoff Area x C Tc Rain Total Cap Vel Pipe Invert Elev HGL Elev Grnd/Rim Elev Line ID
coeff (I) flow full
Line To Incr Total Incr Total Inlet Syst Size Slope Dn Up Dn Up Dn Up
Line
(ft) (ac) (ac) (C) (min) (min) (in/hr) (cfs) (cfs) (ft/s) (in) (%) (ft) (ft) (ft) (ft) (ft) (ft)
1 End 72.075 0.24 4.19 0.75 0.18 3.14 5.0 8.2 6.7 20.93 47.13 6.28 36 0.50 645.00 645.36 646.40 646.83 0.00 663.18 118
2 1 83.034 0.01 0.65 0.75 0.01 0.49 5.0 6.8 7.0 3.43 7.23 5.15 15 1.25 654.71 655.75 655.32 656.50 663.18 666.38 132
3 2 55.012 0.05 0.64 0.75 0.04 0.48 5.0 6.5 7.1 3.42 6.46 4.91 15 1.00 655.95 656.50 656.60 657.25 666.38 666.66 33(1)
4 3 51.613 0.06 0.59 0.75 0.05 0.44 5.0 6.2 7.2 3.19 9.17 5.28 15 2.01 656.70 657.74 657.25 658.46 666.66 668.30 33
5 4 105.743 0.08 0.42 0.75 0.06 0.32 5.0 5.3 7.5 2.37 7.92 4.79 15 1.50 663.31 664.90 663.78 665.51 668.30 670.41 31 (1)
6 5 24.000 0.34 0.34 0.75 0.26 0.26 5.0 5.0 7.6 1.94 9.13 4.57 15 2.00 665.10 665.58 665.51 666.13 670.41 670.41 31 (2)
7 4 24.000 0.11 0.11 0.75 0.08 0.08 5.0 5.0 7.6 0.62 7.00 3.08 15 1.00 663.47 663.71 663.72 664.01 668.30 668.30 81
8 1 74.663 0.36 3.30 0.75 0.27 2.48 5.0 8.0 6.7 16.64 19.58 6.86 24 0.75 652.14 652.70 653.56 654.17 663.18 664.13 35
9 8 153.408 0.30 2.94 0.75 0.23 2.21 5.0 7.4 6.9 15.15 19.58 6.66 24 0.75 652.90 654.05 654.22 655.45 664.13 661.40 37
10 9 88.420 0.15 2.64 0.75 0.11 1.98 5.0 7.1 7.0 13.79 19.53 6.46 24 0.75 654.25 654.91 655.49 656.25 661.40 661.00 39
11 10 85.186 0.46 2.49 0.75 0.35 1.87 5.0 6.7 7.1 13.19 19.61 6.38 24 0.75 655.11 655.75 656.31 657.06 661.00 661.00 41
12 11 121.139 0.57 2.03 0.75 0.43 1.52 5.0 6.4 7.2 10.90 15.47 8.17 18 2.17 656.29 658.92 657.22 660.18 661.00 663.75 43
13 12 143.277 0.79 1.46 0.75 0.59 1.10 5.0 6.0 7.3 7.96 10.50 7.18 15 2.25 659.17 662.40 660.18 663.51 663.75 667.04 45
14 13 190.270 0.67 0.67 0.75 0.50 0.50 5.0 5.0 7.6 3.82 11.18 4.33 15 2.55 662.60 667.46 663.51 668.25 667.04 671.90 47
Project File: BMP-100.stm Number of lines: 14 Run Date: 11/16/2023
NOTES:Intensity=108.84/(Inlet time+ 15.10)A 0.89; Return period=Yrs. 10 ; c=cir e=ellip b=box
Storm Sewers v2024.00

Inlet Report Page 1
Line Inlet ID Q= Q Q Q Junc Curb Inlet Grate Inlet Gutter Inlet Byp
No CIA carry capt Byp Type Line
Ht L Area L W So W Sw Sx n Depth Spread Depth Spread Depr No
(cfs) (cfs) (cfs) (cfs) (in) (ft) (sqft) (ft) (ft) (ft/ft) (ft) (ft/ft) (ft/ft) (ft) (ft) (ft) (ft) (in)
1 CI-101 1.37 0.00 1.37 0.00 Curb 4.0 2.26 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.013 0.28 10.87 0.28 10.87 0.0 Off
2 CI-102 0.06 0.00 0.06 0.00 Curb 4.0 1.00 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.013 0.09 1.81 0.09 1.81 0.0 Off
3 CI-103 0.29 0.00 0.29 0.00 Curb 4.0 8.42 0.00 0.00 0.00 0.017 2.00 0.050 0.020 0.013 0.11 2.36 0.01 0.16 0.0 Off
4 CI-105 0.34 0.00 0.34 0.00 Curb 4.0 8.36 0.00 0.00 0.00 0.013 2.00 0.050 0.020 0.013 0.12 2.96 0.01 0.18 0.0 Off
5 CI-106 0.46 0.00 0.46 0.00 Curb 4.0 10.61 0.00 0.00 0.00 0.019 2.00 0.050 0.020 0.013 0.12 3.17 0.01 0.19 0.0 Off
6 CI-107 1.94 0.00 1.94 0.00 Curb 4.0 23.77 0.00 0.00 0.00 0.027 2.00 0.050 0.020 0.013 0.19 6.36 0.02 0.33 0.0 Off
7 CI-104 0.62 0.00 0.62 0.00 Curb 4.0 11.86 0.00 0.00 0.00 0.017 2.00 0.050 0.020 0.013 0.14 3.97 0.01 0.22 0.0 Off
8 CI-108 2.05 0.00 2.05 0.00 Curb 4.0 19.96 0.00 0.00 0.00 0.012 2.00 0.050 0.020 0.013 0.22 7.83 0.02 0.39 0.0 Off
9 GI-109 1.71 0.00 1.71 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.16 17.81 0.16 17.81 0.0 Off
10 GI-110 0.85 0.00 0.85 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.10 11.96 0.10 11.96 0.0 Off
11 GI-111 2.62 0.00 2.62 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.21 23.02 0.21 23.02 0.0 Off
12 GI-112 3.25 0.00 2.62 0.63 DrGrt 0.0 0.00 0.00 8.88 2.00 0.024 2.00 0.020 0.020 0.013 0.13 15.10 0.13 15.10 0.0 Off
13 GI-113 4.50 0.00 3.72 0.78 DrGrt 0.0 0.00 0.00 10.18 2.00 0.025 2.00 0.020 0.020 0.013 0.15 17.10 0.15 17.10 0.0 Off
14 GI-114 3.82 0.00 3.27 0.55 DrGrt 0.0 0.00 0.00 10.79 2.00 0.028 2.00 0.020 0.020 0.013 0.14 16.10 0.14 16.10 0.0 Off
Project File: BMP-100.stm Number of lines: 14 Run Date: 11/16/2023
NOTES: Inlet N-Values=0.016; Intensity= 108.84/(Inlet time+15.10)A 0.89; Return period=10 Yrs. ; *Indicates Known Q added.All curb inlets are throat.
Storm Sewers v2024.00

Hydraflow Storm Sewers Extension for Autodesk® Civil 3D® Plan
10
9 „
6
7
12
6
5
13
14 4
1
16
3
17
19 20
18
1
Outfall
Project File: BMP-200.stm Number of lines:20 Date: 11/16/2023
Storm Sewers v2024.00

Storm Sewer Tabulation Pagel
Station Len Drng Area Rnoff Area x C Tc Rain Total Cap Vel Pipe Invert Elev HGL Elev Grnd/Rim Elev Line ID
coeff (I) flow full
Line To Incr Total Incr Total Inlet Syst Size Slope Dn Up Dn Up Dn Up
Line
(ft) (ac) (ac) (C) (min) (min) (in/hr) (cfs) (cfs) (ft/s) (in) (%) (ft) (ft) (ft) (ft) (ft) (ft)
1 End 82.990 0.24 12.46 0.75 0.18 8.61 5.0 8.3 6.6 57.08 76.61 8.49 42 0.49 645.00 645.41 647.25 647.77 0.00 663.05 155
2 1 24.022 0.45 11.84 0.75 0.34 8.15 5.0 8.3 6.6 54.12 107.1 12.08 36 2.58 650.85 651.47 652.36 653.86 663.05 663.05 31 (3)
3 2 173.367 0.93 11.39 0.75 0.70 7.81 5.0 7.9 6.8 52.71 63.13 9.19 36 0.90 651.67 653.22 653.86 655.58 663.05 660.14 31
4 3 163.763 0.54 9.10 0.75 0.41 6.09 5.0 7.4 6.9 41.92 74.62 7.80 36 1.25 653.42 655.47 655.58 657.58 660.14 667.49 29(1)
5 4 24.011 0.60 7.95 0.75 0.45 5.23 5.0 7.3 6.9 36.11 57.71 7.52 36 0.75 655.67 655.85 657.58 657.80 667.49 667.48 29
6 5 152.998 0.52 7.35 0.60 0.31 4.78 5.0 6.9 7.0 33.52 41.94 8.79 30 1.05 656.35 657.95 658.04 659.92 667.48 666.40 27
7 6 105.950 1.77 4.22 0.60 1.06 2.90 5.0 6.6 7.1 20.56 20.73 7.49 24 0.84 658.28 659.17 659.92 660.80 666.40 666.40 20
8 7 98.779 0.55 2.45 0.75 0.41 1.84 5.0 6.2 7.2 13.25 15.93 5.62 24 0.50 659.37 659.86 660.80 661.24 666.40 665.77 18
9 8 98.779 0.24 1.90 0.75 0.18 1.43 5.0 5.9 7.3 10.42 10.62 6.76 18 1.02 660.36 661.37 661.56 662.61 665.77 667.75 16
10 9 98.779 0.74 1.67 0.75 0.55 1.25 5.0 5.6 7.4 9.24 9.39 6.03 18 0.80 661.37 662.16 662.61 663.35 667.75 667.15 14
11 10 159.399 0.93 0.93 0.75 0.70 0.70 5.0 5.0 7.6 5.30 5.40 4.32 15 0.60 662.16 663.11 663.64 664.56 667.15 667.54 12
12 6 95.485 1.25 2.61 0.60 0.75 1.57 5.0 5.5 7.4 11.67 12.02 7.46 18 1.31 658.95 660.20 660.14 661.50 666.40 664.91 22
13 12 150.000 1.36 1.36 0.60 0.82 0.82 5.0 5.0 7.6 6.22 9.89 5.82 15 2.00 660.47 663.47 661.50 664.48 664.91 667.91 24
14 4 154.623 0.25 0.61 0.75 0.19 0.46 5.0 5.2 7.5 3.44 6.47 4.92 15 1.00 658.43 659.98 659.08 660.73 667.49 669.05 157
15 14 24.000 0.36 0.36 0.75 0.27 0.27 5.0 5.0 7.6 2.05 4.57 3.63 15 0.50 660.18 660.30 660.77 660.89 669.05 669.05 156
16 3 120.843 0.22 1.36 0.75 0.17 1.02 5.0 5.6 7.4 7.53 8.56 7.25 15 1.50 655.50 657.31 656.41 658.40 660.14 662.57 50
17 16 81.502 0.38 1.13 0.75 0.28 0.85 5.0 5.3 7.5 6.36 6.48 5.98 15 1.01 657.51 658.33 658.51 659.35 662.57 662.97 130(1)
18 17 71.991 0.75 0.75 0.75 0.56 0.56 5.0 5.0 7.6 4.29 9.20 4.98 15 2.03 658.53 659.99 659.35 660.83 662.97 664.43 130
19 1 47.896 0.09 0.38 0.75 0.07 0.29 5.0 5.3 7.5 2.14 9.14 4.94 15 2.00 652.32 653.28 652.73 653.86 663.05 662.66 60
20 19 23.389 0.29 0.29 0.75 0.22 0.22 5.0 5.0 7.6 1.65 5.51 3.72 15 0.73 653.48 653.65 653.95 654.16 662.66 662.68 58
Project File: BMP-200.stm Number of lines:20 Run Date: 11/16/2023
NOTES:Intensity=108.84/(Inlet time+ 15.10)A 0.89; Return period=Yrs. 10 ; c=cir e=ellip b=box
Storm Sewers v2024.00

Inlet Report Page 1
Line Inlet ID Q= Q Q Q Junc Curb Inlet Grate Inlet Gutter Inlet Byp
No CIA carry capt Byp Type Line
Ht L Area L W So W Sw Sx n Depth Spread Depth Spread Depr No
(cfs) (cfs) (cfs) (cfs) (in) (ft) (sqft) (ft) (ft) (ft/ft) (ft) (ft/ft) (ft/ft) (ft) (ft) (ft) (ft) (in)
1 CI-201 1.37 0.00 1.37 0.00 Curb 4.0 15.46 0.00 0.00 0.00 0.010 2.00 0.050 0.020 0.013 0.20 6.81 0.02 0.35 0.0 Off
2 CI-204 2.56 0.00 2.56 0.00 Curb 4.0 20.22 0.00 0.00 0.00 0.008 2.00 0.050 0.020 0.013 0.25 9.38 0.02 0.46 0.0 Off
3 CI-205 5.31 0.00 5.31 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.34 35.66 0.34 35.66 0.0 Off
4 DCI-209 3.08 0.00 3.08 0.00 Curb 4.0 5.08 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.013 0.35 14.37 0.35 14.37 0.0 Off
5 DCI-212 3.42 0.00 3.42 0.00 Curb 4.0 5.64 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.013 0.36 14.78 0.36 14.78 0.0 Off
6 GI-213 2.38 0.00 2.38 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.20 21.71 0.20 21.71 0.0 Off
7 GI-216 8.06 0.00 8.06 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.44 46.46 0.44 46.46 0.0 Off
8 GI-217 3.11 0.00 3.11 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.24 25.57 0.24 25.57 0.0 Off
9 GI-218 1.35 0.00 1.35 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.14 15.53 0.14 15.53 0.0 Off
10 GI-219 4.20 0.00 4.20 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.29 30.77 0.29 30.77 0.0 Off
11 GI-220 5.30 0.00 5.30 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.34 35.62 0.34 35.62 0.0 Off
12 GI-214 5.70 0.00 5.70 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.35 37.28 0.35 37.28 0.0 Off
13 GI-215 6.22 0.00 6.22 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.37 39.42 0.37 39.42 0.0 Off
14 CI-210 1.42 0.00 1.42 0.00 Curb 4.0 17.49 0.00 0.00 0.00 0.015 2.00 i 0.050 0.020 0.013 0.19 6.32 0.02 0.33 0.0 Off
15 DCI-211 2.05 0.00 2.05 0.00 Curb 4.0 21.45 0.00 0.00 0.00 0.016 2.00 0.050 0.020 0.013 0.21 7.35 0.02 0.37 0.0 Off
16 GI-206 1.28 0.00 1.28 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.13 15.02 0.13 15.02 0.0 Off
17 GI-207 2.16 0.00 2.16 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.18 20.49 0.18 20.49 0.0 Off
18 GI-208 4.29 0.00 4.29 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.29 31.19 0.29 31.19 0.0 Off
19 DCI-202 0.51 0.00 0.51 0.00 Curb 4.0 1.00 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.013 0.19 6.64 0.19 6.64 0.0 Off
20 DCI-203 1.65 0.00 1.65 0.00 Curb 4.0 2.73 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.013 0.29 11.72 0.29 11.72 0.0 Off
Project File: BMP-200.stm Number of lines:20 Run Date: 11/16/2023
NOTES: Inlet N-Values=0.016; Intensity= 108.84/(Inlet time+15.10)A 0.89; Return period=10 Yrs. ; *Indicates Known Q added.All curb inlets are throat.
Storm Sewers v2024.00

Hydraflow Storm Sewers Extension for Autodesk® Civil 3D® Plan
7
16
6
6 9
10
24 5 11 12
23
2 21
13
4 14
3 25
15
2 18 19
17
1 20
Outfall
Project File: BMP-300.stm Number of lines:25 Date: 11/16/2023
Storm Sewers v2024.00

Storm Sewer Tabulation Pagel
Station Len Drng Area Rnoff Area x C Tc Rain Total Cap Vel Pipe Invert Elev HGL Elev Grnd/Rim Elev Line ID
coeff (I) flow full
Line To Incr Total Incr Total Inlet Syst Size Slope Dn Up Dn Up Dn Up
Line
(ft) (ac) (ac) (C) (min) (min) (in/hr) (cfs) (cfs) (ft/s) (in) (%) (ft) (ft) (ft) (ft) (ft) (ft)
1 End 76.482 0.23 14.28 0.75 0.17 9.72 5.0 9.7 6.3 61.32 70.92 8.35 42 0.50 645.00 645.38 647.45 647.93 648.38 661.35 161
2 1 186.969 0.01 10.69 0.75 0.01 7.02 0.0 9.2 6.4 45.13 59.65 8.72 36 0.80 647.80 649.30 649.76 651.49 661.35 663.40 62
3 2 49.070 0.12 10.67 0.75 0.09 7.01 5.0 9.0 6.5 45.30 59.66 8.65 36 0.80 649.50 649.89 651.49 652.08 663.40 663.50 83(1)
4 3 143.602 0.13 10.55 0.75 0.10 6.92 5.0 8.6 6.6 45.34 59.65 8.65 36 0.80 650.09 651.24 652.08 653.43 663.50 664.85 83
5 4 133.027 0.02 8.91 0.75 0.01 5.69 5.0 8.2 6.7 37.89 66.70 7.58 36 1.00 651.44 652.77 653.43 654.77 664.85 666.90 85(2)
6 5 85.264 0.19 0.35 0.75 0.14 0.26 5.0 5.6 7.4 1.94 12.12 5.46 15 3.00 661.01 663.57 661.35 664.12 666.90 672.25 85
7 6 24.429 0.16 0.16 0.75 0.12 0.12 5.0 5.0 7.6 0.91 4.95 3.01 15 0.50 665.87 665.99 666.23 666.36 672.25 672.25 87
8 5 23.871 0.51 0.51 0.75 0.38 0.38 5.0 5.0 7.6 2.88 4.56 3.93 15 0.50 661.01 661.13 661.73 661.85 666.90 666.94 158
9 5 51.915 0.07 8.04 0.75 0.05 5.04 5.0 8.0 6.7 33.77 63.46 7.42 36 0.91 652.97 653.44 654.77 655.33 666.90 667.37 112(3)
10 9 188.387 0.48 7.98 0.75 0.36 4.99 5.0 7.4 6.9 34.29 47.16 7.27 36 0.50 653.64 654.58 655.54 656.48 667.37 663.26 112
11 10 153.182 3.54 6.64 0.60 2.12 3.98 5.0 6.2 7.2 28.71 46.98 6.88 36 0.50 655.23 655.99 656.92 657.72 663.26 662.20 103
12 11 147.500 1.16 2.00 0.60 0.70 1.20 5.0 5.7 7.4 8.83 10.59 6.39 18 1.02 657.49 658.99 658.54 660.14 662.20 663.70 101
13 12 140.000 0.84 0.84 0.60 0.50 0.50 5.0 5.0 7.6 3.83 9.13 4.42 15 2.00 659.26 662.06 660.14 662.85 663.70 666.50 126
14 10 215.627 0.21 0.40 0.75 0.16 0.30 5.0 5.5 7.4 2.25 5.78 4.14 15 0.80 656.33 658.05 656.87 658.65 663.26 666.82 108(1)
15 14 23.998 0.19 0.19 0.75 0.14 0.14 5.0 5.0 7.6 1.08 4.57 3.04 15 0.50 658.25 658.37 658.66 658.79 666.82 666.82 108(1)(1)
16 11 147.500 1.10 1.10 0.60 0.66 0.66 5.0 5.0 7.6 5.02 8.77 6.32 15 1.57 657.74 660.06 658.42 660.97 662.20 664.50 123
17 1 24.000 0.43 3.37 0.75 0.32 2.53 5.0 7.7 6.8 17.13 21.65 7.23 24 0.92 650.58 650.80 651.92 652.29 661.35 661.35 91
18 17 153.000 1.24 2.94 0.75 0.93 2.21 5.0 7.2 6.9 15.26 31.99 8.26 24 2.00 651.75 654.81 652.72 656.22 661.35 660.13 93
19 18 130.984 0.78 1.11 0.75 0.59 0.83 5.0 6.8 7.0 5.87 7.13 6.09 15 1.04 655.56 656.92 656.42 657.90 660.13 661.70 95
20 19 164.468 0.33 0.33 0.75 0.25 0.25 5.0 5.0 7.6 1.88 4.50 3.00 15 0.49 657.12 657.92 657.90 658.47 661.70 661.36 128
21 10 23.829 0.45 0.45 0.75 10.34 0.34 5.0 5.0 7.6 2.57 4.93 4.05 15 0.50 657.00 657.12 657.64 657.76 663.26 663.31 105
22 4 23.764 0.11 1.50 0.75 0.08 1.13 5.0 5.6 7.4 8.36 9.89 8.10 15 2.00 653.81 654.29 654.70 655.42 664.85 664.94 89
Project File: BMP-300.stm Number of lines:25 Run Date: 11/16/2023
NOTES:Intensity=108.84/(Inlet time+ 15.10)A 0.89; Return period=Yrs. 10 ; c=cir e=ellip b=box
Storm Sewers v2024.00

Storm Sewer Tabulation Paget
Station Len Drng Area Rnoff Area x C Tc Rain Total Cap Vel Pipe Invert Elev HGL Elev Grnd/Rim Elev Line ID
coeff (I) flow full
Line To Incr Total Incr Total Inlet Syst Size Slope Dn Up Dn Up Dn Up
Line
(ft) (ac) (ac) (C) (min) (min) (in/hr) (cfs) (cfs) (ft/s) (in) (%) (ft) (ft) (ft) (ft) (ft) (ft)
23 22 54.544 0.38 1.39 0.75 0.29 1.04 5.0 5.4 7.5 7.78 9.89 7.36 15 2.00 654.49 655.58 655.42 656.68 664.94 661.12 54(1)
24 23 116.983 1.01 1.01 0.75 0.76 0.76 5.0 5.0 7.6 5.76 6.07 5.62 15 0.75 655.78 656.66 656.75 657.63 661.12 661.10 54
25 18 99.000 0.59 0.59 0.75 0.44 0.44 5.0 5.0 7.6 3.36 6.42 4.87 15 0.99 655.69 656.67 656.33 657.41 660.13 661.11 98
Project File: BMP-300.stm Number of lines:25 Run Date: 11/16/2023
NOTES:Intensity=108.84/(Inlet time+ 15.10)A 0.89; Return period=Yrs. 10 ; c=cir e=ellip b=box
Storm Sewers v2024.00

Inlet Report Page 1
Line Inlet ID Q= Q Q Q Junc Curb Inlet Grate Inlet Gutter Inlet Byp
No CIA carry capt Byp Type Line
Ht L Area L W So W Sw Sx n Depth Spread Depth Spread Depr No
(cfs) (cfs) (cfs) (cfs) (in) (ft) (sqft) (ft) (ft) (ft/ft) (ft) (ft/ft) (ft/ft) (ft) (ft) (ft) (ft) (in)
1 DCI-301 1.31 0.00 1.31 0.00 Curb 4.0 2.27 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.013 0.27 10.55 0.27 10.55 0.0 Off
2 CI-307 0.00 0.00 0.00 0.00 Curb 4.0 1.00 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.000 0.06 1.20 0.06 1.20 0.0 Off
3 CI-308 0.70 0.00 0.70 0.00 Curb 4.0 1.22 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.000 0.22 7.95 0.22 7.95 0.0 Off
4 CI-309 0.77 0.00 0.77 0.00 Curb 4.0 1.33 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.000 0.23 8.29 0.23 8.29 0.0 Off
5 CI-313 0.10 0.00 0.10 0.00 Curb 4.0 1.00 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.000 0.11 2.29 0.11 2.29 0.0 Off
6 CI-315 1.08 0.00 1.08 0.00 Curb 4.0 1.87 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.000 0.25 9.71 0.25 9.71 0.0 Off
7 CI-316 0.91 0.00 0.91 0.00 Curb 4.0 1.57 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.000 0.24 8.99 0.24 8.99 0.0 Off
8 CI-314 2.88 0.00 2.88 0.00 Curb 4.0 4.99 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.000 0.34 13.84 0.34 13.84 0.0 Off
9 CI-318 0.38 0.00 0.38 0.00 Curb 4.0 1.00 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.000 0.17 5.46 0.17 5.46 0.0 Off
10 DCI-319 2.75 0.00 2.75 0.00 Curb 4.0 4.77 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.000 0.33 13.67 0.33 13.67 0.0 Off
11 GI-323 16.14 0.00 16.14 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.71 72.65 0.71 72.65 0.0 Off
12 GI-325 5.29 0.00 5.29 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.34 35.57 0.34 35.57 0.0 Off
13 GI-326 3.83 0.00 3.83 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.27 29.07 0.27 29.07 0.0 Off
14 CI-321 1.21 0.00 1.21 0.00 Curb 4.0 2.09 0.00 0.00 0.00 Sag 2.00 i 0.050 0.020 0.000 0.26 10.20 0.26 10.20 0.0 Off
15 CI-322 1.08 0.00 1.08 0.00 Curb 4.0 1.88 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.000 0.25 9.74 0.25 9.74 0.0 Off
16 GI-324 5.02 0.00 5.02 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.32 34.40 0.32 34.40 0.0 Off
17 DCI-302 2.43 0.00 2.43 0.00 Curb 4.0 4.21 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.000 0.32 13.17 0.32 13.17 0.0 Off
18 GI-303 7.07 0.00 7.07 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.41 42.73 0.41 42.73 0.0 Off
19 GI-304 4.45 0.00 4.45 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.30 31.90 0.30 31.90 0.0 Off
20 GI-305 1.88 0.00 1.88 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.17 18.84 0.17 18.84 0.0 Off
21 DCI-320 2.57 0.00 2.57 0.00 Curb 4.0 4.45 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.000 0.33 13.39 0.33 13.39 0.0 Off
22 CI-310 0.64 0.00 0.64 0.00 Curb 4.0 1.11 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.000 0.21 7.60 0.21 7.60 0.0 Off
23 GI-311 2.17 0.00 2.17 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.19 20.51 0.19 20.51 0.0 Off
Project File: BMP-300.stm Number of lines:25 Run Date: 11/16/2023
NOTES: Inlet N-Values=0.016; Intensity= 108.84/(Inlet time+15.10)A 0.89; Return period=10 Yrs. ; *Indicates Known Q added.All curb inlets are throat.
Storm Sewers v2024.00

Inlet Report Page2
Line Inlet ID Q= Q Q Q Junc Curb Inlet Grate Inlet Gutter Inlet Byp
No CIA carry capt Byp Type Line
I Ht L Area L W So W Sw Sx n Depth Spread Depth Spread Depr No
(cfs) (cfs) (cfs) (cfs) (in) (ft) (sqft) (ft) (ft) (ft/ft) (ft) (ft/ft) (ft/ft) (ft) (ft) (ft) (ft) (in)
24 GI-312 5.76 0.00 5.76 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.36 37.52 0.36 37.52 0.0 Off
25 GI-306 3.36 0.00 3.36 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.25 26.82 0.25 26.82 0.0 Off
Project File: BMP-300.stm Number of lines:25 Run Date: 11/16/2023
NOTES: Inlet N-Values=0.016; Intensity= 108.84/(Inlet time+15.10)A 0.89; Return period=10 Yrs. ; *Indicates Known Q added.All curb inlets are throat.
Storm Sewers v2024.00

Hydraflow Storm Sewers Extension for Autodesk® Civil 3D® Plan
10
9
1
13
Outfall 12 14
3
4
11 8
5
6
7
Project File: BMP-400.stm Number of lines: 14 Date: 11/16/2023
Storm Sewers v2024.00

Storm Sewer Tabulation Pagel
Station Len Drng Area Rnoff Area x C Tc Rain Total Cap Vel Pipe Invert Elev HGL Elev Grnd/Rim Elev Line ID
coeff (I) flow full
Line To Incr Total Incr Total Inlet Syst Size Slope Dn Up Dn Up Dn Up
Line
(ft) (ac) (ac) (C) (min) (min) (in/hr) (cfs) (cfs) (ft/s) (in) (%) (ft) (ft) (ft) (ft) (ft) (ft)
1 End 78.698 0.06 5.39 0.75 0.05 3.73 5.0 9.9 6.3 23.40 47.16 6.49 36 0.50 645.00 645.39 646.49 646.95 0.00 664.28 122
2 1 81.817 0.05 5.33 0.75 0.04 3.69 5.0 9.6 6.3 23.37 41.01 7.73 30 1.00 650.61 651.43 651.96 653.07 664.28 662.59 66(1)
3 2 34.366 0.04 4.42 0.75 0.03 3.00 5.0 9.4 6.4 19.12 29.00 6.29 30 0.50 651.63 651.80 653.11 653.29 662.59 662.14 68(2)
4 3 59.011 0.05 4.38 0.75 0.04 2.97 5.0 9.1 6.4 19.11 29.00 4.89 30 0.50 652.00 652.30 653.99 654.05 662.14 661.39 68
5 4 113.315 0.40 4.19 0.75 0.30 2.83 5.0 8.6 6.6 18.59 29.00 5.17 30 0.50 652.50 653.07 654.68 654.53 661.39 660.53 68(1)
6 5 207.380 0.30 3.79 0.75 0.23 2.53 5.0 7.6 6.8 17.27 29.18 6.14 30 0.51 653.17 654.22 654.55 655.62 660.53 660.00 70
7 6 145.787 0.93 3.49 0.75 0.70 2.31 5.0 7.1 7.0 16.04 17.07 6.17 24 0.57 654.22 655.05 655.76 656.59 660.00 660.40 72
8 7 246.134 0.48 2.56 0.75 0.36 1.61 5.0 6.0 7.3 11.72 27.92 4.92 24 1.52 655.15 658.90 656.89 660.13 660.40 664.70 74
9 8 176.368 0.33 2.08 0.60 0.20 1.25 5.0 5.4 7.5 9.32 11.27 6.69 18 1.15 659.10 661.13 660.14 662.31 664.70 667.40 76
10 9 109.688 1.75 1.75 0.60 1.05 1.05 5.0 5.0 7.6 7.98 8.15 5.26 18 0.60 661.33 661.99 662.53 663.19 667.40 666.70 78
11 4 23.247 0.13 0.13 0.75 0.10 0.10 5.0 5.0 7.6 0.76 4.72 2.81 15 0.53 656.79 656.91 657.13 657.25 661.39 661.40 140
12 2 24.000 0.23 0.87 0.75 0.17 0.65 5.0 5.4 7.5 4.87 10.21 6.70 15 2.50 655.13 655.73 655.74 656.62 662.59 662.59 66
13 12 25.765 0.25 0.64 0.75 0.19 0.48 5.0 5.2 7.5 3.60 10.16 4.87 15 2.47 655.93 656.57 656.62 657.33 662.59 663.04 115(1)(1)
14 13 23.756 0.39 0.39 0.75 0.29 0.29 5.0 5.0 7.6 2.22 10.18 3.99 15 2.48 656.77 657.36 657.33 657.95 663.04 663.11 115(1)
Project File: BMP-400.stm Number of lines: 14 Run Date: 11/16/2023
NOTES:Intensity=108.84/(Inlet time+ 15.10)A 0.89; Return period=Yrs. 10 ; c=cir e=ellip b=box
Storm Sewers v2024.00

Inlet Report Page 1
Line Inlet ID Q= Q Q Q Junc Curb Inlet Grate Inlet Gutter Inlet Byp
No CIA carry capt Byp Type Line
Ht L Area L W So W Sw Sx n Depth Spread Depth Spread Depr No
(cfs) (cfs) (cfs) (cfs) (in) (ft) (sqft) (ft) (ft) (ft/ft) (ft) (ft/ft) (ft/ft) (ft) (ft) (ft) (ft) (in)
1 CI-401 0.35 0.00 0.35 0.00 Curb 4.0 1.00 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.000 0.16 5.12 0.16 5.12 0.0 Off
2 CI-402 0.27 0.00 0.27 0.00 Curb 4.0 1.00 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.000 0.15 4.38 0.15 4.38 0.0 Off
3 CI-406 0.22 0.00 0.22 0.00 Curb 4.0 1.00 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.000 0.14 3.83 0.14 3.83 0.0 Off
4 CI-407 0.28 0.00 0.28 0.00 Curb 4.0 1.00 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.000 0.15 4.41 0.15 4.41 0.0 Off
5 DCI-409 2.30 0.00 2.30 0.00 Curb 4.0 3.99 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.000 0.32 12.95 0.32 12.95 0.0 Off
6 GI-410 1.71 0.00 1.71 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.16 17.81 0.16 17.81 0.0 Off
7 GI-411 5.30 0.00 5.30 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.34 35.62 0.34 35.62 0.0 Off
8 GI-412 2.74 0.00 2.74 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.22 23.63 0.22 23.63 0.0 Off
9 GI-413 1.50 0.00 1.50 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.15 16.51 0.15 16.51 0.0 Off
10 GI-414 7.98 0.00 7.98 0.00 DrGrt 0.0 0.00 5.06 2.53 2.00 Sag 2.00 0.020 0.020 0.013 0.44 46.16 0.44 46.16 0.0 Off
11 CI-408 0.76 0.00 0.76 0.00 Curb 4.0 1.31 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.000 0.22 8.24 0.22 8.24 0.0 Off
12 CI-403 1.31 0.00 1.31 0.00 Curb 4.0 2.28 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.000 0.27 10.56 0.27 10.56 0.0 Off
13 CI-404 1.41 0.00 1.41 0.00 Curb 4.0 2.44 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.000 0.28 10.87 0.28 10.87 0.0 Off
14 CI-405 2.22 0.00 2.22 0.00 Curb 4.0 3.85 0.00 0.00 0.00 Sag 2.00 0.050 0.020 0.013 0.32 12.80 0.32 12.80 0.0 Off
Project File: BMP-400.stm Number of lines: 14 Run Date: 11/16/2023
NOTES: Inlet N-Values=0.016; Intensity= 108.84/(Inlet time+15.10)A 0.89; Return period=10 Yrs. ; *Indicates Known Q added.All curb inlets are throat.
Storm Sewers v2024.00

INLET CAPACITY CHART
DATE: 10/10/2023
HERITAGE AT MARVIN DRAWN BY: CPF
PROJECT: 326-256 CHECKED BY: CAP
Maximum Allowable Spread:7.5 Ft
Inlet Drainage Runoff Surface Q(cfs) B p ass
Type No. Area(ac) C Sub. Total Slope(%) K Spread Intercept Q To Inlet#
CI 0.24 0.72 LP 1 LP 1 4.98 1 0.72 0.00
! F y !
CI 0.01 0.03 2.00 27.0 1.58 0.03 0.00
✓ r r
CI 0.05 0.15 1.00 21.5 3.29 E., 0.15 0.00
✓ r 1 r
CI 0.11 0.33 2.00 27.0 F 4.79 j 0.54 0.04
CI 0.06 0.18 2.00 27.0 4.47 0.48 0.00
L L J L
CI 0.08 0.24 2.00 1 27.00 1 3.45 1 0.24 1 0.00
i J i
CI 0.34 1.02 2.00 1' 27.00 5.93 0.77 1 0.25
CI 0.36 1.08 2.00 I 27.00 1 6.13 0.82 0.30
✓ r i r
CI 0.24 0.72 1.00 21.50 ; 5.92 0.61 0.11
✓ r 1 r
DCI 0.09 0.27 LP LP 2.54 0.38 0.00
I r r
DCI 0.29 0.87 LP I LP L 6.46 j 1.52 I 0.00
CI 0.45 1.35 1.00 I 21.50 I 7.50 I 0.91 1 0.44
✓ L J L
DCI 0.54 1.62 LP I LP F 1 6.74 J 1 1.62 1 0.00
•
DCI 0.25 0.75 1.55 1 24.0 5.54 0.75 0.00
✓ r i r
DCI 0.36 1.08 1.55 24.0 6.35 1.00 0.08
✓ r 1 r
DCI 0.60 1.80 LP LP 7.44 0 1.88 0.00
r r 1 r
DCI 0.23 0.69 LP LP F 3.81 i 0.69 � 0.00
DCI 0.43 1.29 LP 1 LP L 5.79 ,j 1.29 0.00
CI 0.01 0.03 1.00 i 1 21.5 1 L 1.80 J 1 0.03 1 0.00
i
CI 0.12 0.36 1.00 21.5 4.57 di 0.36 0.00

Inlet Drainage Runoff Surface Q cfs B p ass
Tpe No. Area(ac) C Sub. Total Slope(%) K Spread Intercept Q To Inlet#
CI 0.13 0.39 1.00 21.5 4.71 0.39 0.00
CI 0.11 0.33 1.00 j 21.5 F 6.53 � 0.72 j 0.21
CI 0.02 0.06 2.00 I 27.0 L 2.05 J 0.06 I 0.00
L L J L
CI 0.51 1.53 3.00 1 30.0 1 6.51 1 1.00 1 0.60
• L
CI 0.19 0.57 10.00 1 37.5 1 3.52 0.45 1 0.12
• F y •
CI 0.16 0.48 10.00 ; 37.5 3.30 0.40 0.08
✓ r r
CI 0.01 0.03 2.00 27.0 1.58 E., 0.03 0.00
✓ r -1 r
CI 0.07 0.21 2.00 1 27.0 3.88 0.33 0.00
DCI 0.48 1.44 LP LP r 6.40 1 1.50 j 0.00
L L J L
DCI 0.45 1.35 LP 1 LP L L 6.07 1 1.38 1 0.00
L
CI 0.21 0.63 2.00 1 27.0 1 4.95 4J 0.57 1 0.06
• F .
CI 0.19 0.57 2.00 1 27.0 4.77 0.54 0.03
✓ r r
CI 0.06 0.18 2.00 27.0 3.09 ti 0.18 0.00
✓ r -1 r
CI 0.05 0.15 2.00 27.0 3.69 0.29 0.00
I r r
CI 0.23 0.69 2.00 i 27.0 L 5.42 j 0.66 I 0.14
CI 0.25 0.75 2.00 I 27.0 5.28 0.64 1 0.11
L L j L
CI 0.39 1.17 2.00 1 27.0 1 6.24 1 0.84 1 0.33
• L -. 4
CI 0.04 0.12 2.50 1 27.0 2.55 1 0.12 0.00
✓ r ti r
CI 0.05 0.15 2.50 27.0 2.77 0.15 0.00
✓ r r
CI 0.13 0.39 1.00 21.5 5.92 1 0.61 0.11
r r r
DCI 0.40 1.20 LP i LP IL 5.84 j 1.31 1 0.00

RIPRAP APRON CALCULATIONS

DESIGN OF RIPRAP OUTLET PROTECTION
User Input Data
Calculated Value
Reference Data
Designed By: CPF Date: 11/9/2023
Checked By: CAP Date: 11/10/2023
Company: CEC,Inc.
Project Name: Heritage at Marvin
Project No.: 326-256
Site Location(City/Town) Marvin,NC
Culvert Id. Pond Inlet Wetpond#1 EW-100
Total Drainage Area(acres) 18.99
Step 1. Determine the tailwater depth from channel characteristics below the
pipe outlet for the design capacity of the pipe- If the tailwater depth is less
than half the outlet pipe diameter.it is classified minimum tailwater condition
If it is greater than half the pipe diameter,it is classified maximum condition.
Pipes that outlet onto wide flat areas with no defined channel are assumed
to have a minimum tailwater condition unless reliable flood stage elevations
show otherwise.
Outlet pipe diameter,Do(in.) 36
Tailwater depth(in.) 18
Minimum/Maximum tailwater? Max TW(Fig.8.06b)
Discharge(cfs) 20.93 (10-year Storm)
Velocity(ft./s) 6.29
Step 2. Based on the tailwater conditions determined in step 1,enter Figure
8.06a or Figure 8.06b.and determine d50 riprap size and minimum apron length
(1„). The ds0 size is the median stone size in a well-graded nprap apron.
Step 3. Determine apron width at the pipe outlet,the apron shape.and the
apron width at the outlet end from the same figure used in Step 2.
Minimum TW Maximum TW
Fioure 8.06a Fioure 8.06b
Riprap d5o,(ft.) 1.5 1.5
Minimum apron length,La(ft.) 20 44
Apron width at pipe outlet(ft.) 9 9
Apron shape Trapezoidal Trapezoidal
Apron width at outlet end(ft.) 23 20.6
Step 4. Determine the maximum stone diameter:
d , =1.5xd,a
Minimum TW Maximum TW
Max Stone Diameter,dmax(ft.) 2.25 2.25
Step 5. Determine the apron tluckness:
Apron thickness=1.5 x d „
Minimum TW Maximum TW
Apron Thickness(ft.) 3.375 3.375
Step 6. Fit the nprap apron to the site by making it level for the minimum
length, L. from Figure 8.06a or Figure 8.06b. Extend the apron farther
downstream and along channel banks until stability is assured. Keep the
apron as straight as possible and align it with the flow of the receiving stream.
Make any necessary alignment bends near the pipe outlet so that the entrance
into the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure
stability.
It may be necessary to increase the size of riprap where protection of the
channel side slopes is necessary(Appendix 8.05). Where overfalls exist at
pipe outlets or flows are excessive,a plunge pool should be considered,see
page 8.06.8.

Figure 8.06a: Design of outlet protection from a round pipe flowing full, minimum
tailwater condition (Tw<0.5 diameter)
3 0
Outlet W • 00 + La I
pipe ,f.., . . e r,
diameter (00)
SO
La- Liliiiiii it ater 0.5D0 . ... - /;�
419
o\,oto60�� , t . , =.i/ap041
9�r uti m t, .
men {! •ti • ' �"
50WC\ .. :. .
A # . .
e�O. feI/
•
�j�i!
30 2e O. J' 0►'-'
e
::1•010. .
1:. ,„,-•'-'-;"-*-- ' I : . . ',joie
Ens.„,. ...13 . Apr714,A- —
. . : . 1 _ , ••4 -4000A:41. ActIF• 1
0 ..... 4 , i :- 1, -—1 p of—,4 I 400;,I r4 I 1 1: ./A 6 ref!Up 1 14 1..':"'
sr 25 to
'11(01110"de il 0 , cr
. . I il i: •adage./ ;
v 1S l��
s
0
3 S 10 20 50 100 200 500 1000
Discharge(ft3/sec)
Curves may not be extrapolated
Figure 8.06a Design of outlet protection protection from a round pipe flowing full,minimum tailwater condition Cr*<0.5 diameter)
Re..1:93 8.06.3

DESIGN OF RIPRAP OUTLET PROTECTION
User Input Data
Calculated Value
Reference Data
Designed By: ERR Date: 11/9/2023
Checked By: CAP Date: 11/10/2023
Company: CEC,Inc.
Project Name: Heritage at Marvin
Project No.: 326-256
Site Location(City/Town) Marvin,NC
Culvert Id. Pond Inlet Wetpond#1 EW-200
Total Drainage Area(acres) 18.99
Step 1. Determine the tailwater depth from channel characteristics below the
pipe outlet for the design capacity of the pipe- If the tailwater depth is less
than half the outlet pipe diameter.it is classified minimum tailwater condition.
If it is greater than half the pipe diameter,it is classified maximum condition.
Pipes that outlet onto wide flat areas with no defined channel are assumed
to have a minimum tailwater condition unless reliable flood stage elevations
show otherwise.
Outlet pipe diameter,Do(in.) 42
Tailwater depth(in.) 21
Minimum/Maximum tailwater? Max TW(Fig.8.06b)
Discharge(cfs) 57.08 (10-year Storm)
Velocity(ft./s) 8.52
Step 2. Based on the tailwater conditions determined in step 1.enter Figure
8.06a or Figure 8.06b.and determine d50 riprap size and minimum apron length
(1„). The dso size is the median stone size in a well-graded nprap apron.
Step 3. Determine apron width at the pipe outlet,the apron shape.and the
apron width at the outlet end from the same figure used in Step 2.
Minimum TW Maximum TW
Figure 8.06a Figure 8.06b
Riprap ds°,(ft.) 1.5 1.5
Minimum apron length,La(ft.) 22 16
Apron width at pipe outlet(ft.) 10.5 10.5
Apron shape Trapezoidal Trapezoidal
Apron width at outlet end(ft.) 25.5 9.9
Step 4. Determine the maximum stone diameter.
dn,,,,=1.5 x d,a
Minimum TW Maximum TW
Max Stone Diameter,dmax(ft.) 2.25 2.25
Step 5. Determine the apron tluckness:
Apron thickness=1.5 x d ,R
Minimum TW Maximum TW
Apron Thickness(ft.) 3.375 3.375
Step 6. Fit the nprap apron to the site by making it level for the minimum
length, L, from Figure 8-06a or Figure 8.06b. Extend the apron farther
downstream and along channel banks until stability is assured. Keep the
apron as straight as possible and align it with the flow of the receiving stream.
Make any necessary alignment bends near the pipe outlet so that the entrance
into the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure
stability.
It may be necessary to increase the size of riprap where protection of the
channel side slopes is necessary(Appendix 8.05). Where overfalls exist at
pipe outlets or flows are excessive,a plunge pool should be considered,see
page 8.06.8.

Figure 8.06a: Design of outlet protection from a round pipe flowing full, minimum
tailwater condition (Tw<0.5 diameter)
3 0
Outlet W . 0o + La
pipe f... . . e
diameter (00)
80 . 1)
ilwater < 0.5p0
�a`�\�l 70 •__
O -. .' tea_ i : I 1.. ?
ta
•
4
' 0 All
30 _. o :., :...
Or FA
,--
.i. .� k
o
•
. lir-:- ....-
•
0 } :::. ..::::. ��4Y3
.MAY" 2 cn
dio -ilk
-25 '07 . A"plir . . , . .-. g
v= 10 0 '
-
I
3 5 10 20 50 100 200 500 1000
Discharge(ft3/sec)
Curves may not be extrapolated
Figure 8.06a Design of outlet protection protection from a round pipe flowing full•minimum tailwater condition(T,..c 0.5 diameter)
Re..1:93 8.06.3

DESIGN OF RIPRAP OUTLET PROTECTION
User Input Data
Calculated Value
Reference Data
Designed By: ERR Date: 11/9/2023
Checked By: CAP Date: 11/10/2023
Company: CEC,Inc.
Project Name: Heritage at Marvin
Project No.: 326-256
Site Location(City/Town) Marvin,NC
Culvert Id. Pond Inlet Wetpond#2 EW-300
Total Drainage Area(acres) 22.07
Step 1. Determine the tailwater depth from channel characteristics below the
pipe outlet for the design capacity of the pipe. If the tailwater depth is less
than half the outlet pipe diameter.it is classified minimum tailwater condition.
If it is greater than half the pipe diameter,it is classified maximum condition.
Pipes that outlet onto wide flat areas with no defined channel are assumed
to have a minimum tailwater condition unless reliable flood stage elevations
show otherwise.
Outlet pipe diameter,Do(in.) 42
Tailwater depth(in.) 21
Minimum/Maximum tailwater? Max TW(Fig.8.06b)
Discharge(cfs) 61.32 (10-year Storm)
Velocity(ft./s) 8.52
Step 2. Based on the tailwater conditions determined in step 1,enter Figure
8.06a or Figure 8.06b,and determine dsa riprap size and minimum apron length
(1...). The d9 size is the median stone size in a well-graded nprap apron.
Step 3. Determine apron width at the pipe outlet,the apron shape,and the
apron width at the outlet end from the same figure used in Step 2.
Minimum TW Maximum TW
Fioure 8.06a Fioure 8.06b
Riprap d5o,(ft.) 1.5 1.5
Minimum apron length,La(ft.) 21 30
Apron width at pipe outlet(ft.) 10.5 10.5
Apron shape Trapezoidal Trapezoidal
Apron width at outlet end(ft.) 24.5 15.5
Step 4. Determine the maximum stone diameter:
d =1.5xd„
Minimum TW Maximum TW
Max Stone Diameter,dmax(ft.) 2.25 2.25
Step 5. Determine the apron thickness.
Apron thickness=1.5 x d „
Minimum TW Maximum TW
Apron Thickness(ft.) 3.375 3.375
Step 6. Fit the nprap apron to the site by making it level for the minimum
length, L. from Figure 8.06a or Figure 8.06b. Extend the apron farther
downstream and along channel banks until stability is assured. Keep the
apron as straight as possible and align it with the flow of the receiving stream.
Make any necessary alignment bends near the pipe outlet so that the entrance
into the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure
stability.
It may be necessary to increase the size of riprap where protection of the
channel side slopes is necessary(Appendix 8.05). Where overfalls exist at
pipe outlets or flows are excessive,a plunge pool should be considered,see
page 8.06.8.

Figure 8.06a: Design of outlet protection from a round pipe flowing full, minimum
tailwater condition (Tw<0.5 diameter)
3 0
Outlet W • Do + La
pipe L.. . . e
diameter (00) 1
80 . 1)
ilwater 0.5D0 : ;
`O 70 •— . ' .•:
O .... •
t `a.. t : I p
•
eP
s .
nrirr
• -"'" g.
...._ .4,,,,,,i,
,.
-- ,-. I -1-1-i:
3(;) .....:..... ,__,--.-:...... .. . 'L\ " .i , A„t,
1°-.:1:::7— ... .-,,.. „ . 7-.: , . . . *'• ,.'4 r.4/01;19011 gerb...,1:- !-• Fl-
:. .. .. ........... 1 .. rir;o 2 to
' * : :. i..41..#1. .4;eigic400 oal .' wrpr lb: -:: . (x$
v _p f
1 v= 10 0 .;„„ ��` -a�1��
v_5 -••.'r
0
3 5 10 20 50 100 200 500 1000
Discharge(ft3/sec)
Curves may not be extrapolated
Figure 8.06a Design of outlet protectan protection from a round pipe flowing full•minimum tailwater condition(T,..c 0.5 dameter)
Re..1:93 8.06.3

DESIGN OF RIPRAP OUTLET PROTECTION
User Input Data
Calculated Value
Reference Data
Designed By: ERR Date: 11/9/2023
Checked By: CAP Date: 11/10/2023
Company: CEC,Inc.
Project Name: Heritage at Marvin
Project No.: 326-256
Site Location(City/Town) Marvin,NC
Culvert Id. Pond Inlet Wetpond#2 EW-400
Total Drainage Area(acres) 22.07
Step 1. Determine the tailwater depth from channel characteristics below the
pipe outlet for the design capacity of the pipe. If the tailwater depth is less
than half the outlet pipe diameter.it is classified minimum tailwater condition.
If it is greater than half the pipe diameter,it is classified maximum condition.
Pipes that outlet onto wide flat areas with no defined channel are assumed
to have a minimum tailwater condition unless reliable flood stage elevations
show otherwise.
Outlet pipe diameter,Do(in.) 36
Tailwater depth(in.) 18
Minimum/Maximum tailwater? Max TW(Fig.8.06b)
Discharge(cfs) 23.40 (10-year Storm)
Velocity(ft./s) 6.3
Step 2. Based on the tailwater conditions determined m step 1.enter Figure
8.06a or Figure 8.06b,and determine dsa riprap size and minimum apron length
(1...). The d9 size is the median stone size in a well-graded nprap apron.
Step 3. Determine apron width at the pipe outlet,the apron shape,and the
apron width at the outlet end from the same figure used in Step 2.
Minimum TW Maximum TW
Figure 8.06a Figure 8.06b
Riprap dso,(ft.) 1.5 1.5
Minimum apron length,La(ft.) 20 55
Apron width at pipe outlet(ft.) 9 9
Apron shape Trapezoidal Trapezoidal
Apron width at outlet end(ft.) 23 25
Step 4. Determine the maxuinum stone diameter.
d =1.5xd„
Minimum TW Maximum TW
Max Stone Diameter,dmax(ft.) 2.25 2.25
Step 5. Determine the apron tluckness.
Apron thickness=1.5 x d,,„
Minimum TW Maximum TW
Apron Thickness(ft.) 3.375 3.375
Step 6. Fit the nprap apron to the site by making it level for the minimum
length, L, from Figure 8.06a or Figure 8.06b. Extend the apron farther
downstream and along channel banks until stability is assured. Keep the
apron as straight as possible and align it with the flow of the receiving stream.
Make any necessary alignment bends near the pipe outlet so that the entrance
into the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure
stability.
It may be necessary to increase the size of nprap where protection of the
channel side slopes is necessary(Appendix 8.05). Where overfalls exist at
pipe outlets or flows are excessive,a plunge pool should be considered,see
page 8.06.8.

Figure 8.06a: Design of outlet protection from a round pipe flowing full, minimum
tailwater condition (Tw<0.5 diameter)
3 0
Outlet W Do La I •
pipe ,f... . .
a•••
diameter (00) • fir/
i . .. /' tater 0.5D0 ..11
CrSO
- Liiiiiih
idi
„.,), . , , . •
,0,0,,- _.; ,_-•.- 4, . ,...,,,,,,
tti cot, .•
ve•
I :0PrAlrirji.
Air.4002,.. .
. . .
.0,..••••...:. 4. 111."1" - • •. t ,,,,
0 --- 1 '.. i _L_ 7_dir._ArroOrAr Kir/0 II..• 2 ti
II ..........--•• .. '•Apd/r;i7.4•0111°.0111FrAigiWIlir 11.
CC
s' " .4 d°f.":0 0'•Ce rA••p P."' 1 I or . .
= is itrtiI/I ��� t
...fir
v-sl r I I 1 o
3 5 10 20 50 100 200 500 1000
Discharge(ft3/sec)
Curves may not be extrapolated
Figure 8.06a Design of outlet protection protection from a round pipe flowing full,minimum tailwater condition(T.,<0.5 diameter)
Re..1:93 8.06.3