SW3161201_5 - SWM Calculations 04-25-20_5/5/2020

Stormwater Management
Calculations
for
The Conservancy
at Waxhaw Creek Phase 2
in
Union County, NC
Stormwater Permit No. SW3161201
Prepared for:
True Homes, LLC
November 28, 2016
Richard L. Modlin, P.E.
Civil Engineer
7215 Terrace Drive, Charlotte, NC 28211
Phone: [phone]
[e-mail]
11-28-16
REVISED 04-25-20
Contents 
Modification to Stormwater Permit 
Background Information 
 Overview 
Existing Site & Drainage Characteristics 
Soils 
Development Plan for Site 
  Project Data 
USGS Map 
BMP Design 
 Overview 
BMP‐1 Calculations and Pond Data 
BMP‐2 Calculations and Pond Data 
BUA Calculations 
Lot BUA Summary 
Attachment to Form SW401 Part II 
Attachment to Form SWU‐101 Part IV, Item 11 
Time of Concentration Worksheets 
BMP‐1 Pre‐Development 
BMP‐1 Post‐Development 
BMP‐2 Pre‐Development 
BMP‐2 Post‐Development 
HydroCAD Reports 
Pre‐Development 
 Post Development 
1‐yr, 24‐hour 
Extended Detention  
Outlet Stabilization 
Modification to Stormwater Permit No. SW3161201 
The Conservancy at Waxhaw Creek Phase 2 
Union County, NC 
February 13, 2020 
These calculations have been revised to reflect modifications to the two wet‐pond 
designs.   
Based on as‐built field surveys of the two sediment basins, the proposed final basin 
contours were modified to reduce the amount of earthwork required for conversion of 
the basins to permanent ponds.   Based on the original inflow hydrograph, the modified 
storage was input for each design, modelled and the outlet controls adjusted 
accordingly.    
Background Information
Overview
The project is located off the north side of Steele Road (SR 1177), approximately 4,400 feet west
of its intersection with Lancaster Highway (NC 200) in Union County, NC. The entire property
comprises approximately 127.6 acres named The Conservancy at Waxhaw Creek and is being
developed for single-family homes in three separate phases.
The "Project Site" as noted herein, refers to a 53.85-acre tract, Phase 2 of the development.
Phase 1, with some 38 lots, has been developed and adjoins the proposed Phase 2 to the south.
The future Phase 3 will develop the remaining area north of Phase 2.
Phase 2 will ultimately construct approximately 3,500 feet of roadway to serve approximately 40
new single-family lots. Phase 2 will connect to the existing 800-foot roadway Hawk View Road
(constructed in Phase 1) that extends to Steele Road (SR 1177).
The property is bounded to both the southwest and the northeast by jurisdictional streams within
the conservation area owned by the Catawba Lands Conservancy. A FEMA floodplain lies west of
the property. There are no impacts to jurisdictional streams or wetlands for the proposed work
depicted in this plans.
Existing Site & Drainage Characteristics
The existing site is undeveloped and heavily wooded. Existing ground slopes within the project
area range from 2 to 15 percent. The site drains generally southeast to northwest. The
developed portions of the site will drain to each of two proposed wet detention basins:
to the northwest property corner, (Area 1) and
to a point roughly 1400 feet southeast of the northwest property corner (Area 2).
On-Site BMP Drainage Areas
Area 1 is approximately 17.3 acres and drains from a high point elevation 585 to elevation 520
over a hydraulic length of approximately 1,700 linear feet.
Area 2 drains from a high point (400 feet off-site) elevation 655 to elevation 542 over a hydraulic
length of approximately 1,600 linear feet. The 22.6-acre drainage area includes runoff from two
off-site areas:
3.2 acres from adjacent undeveloped property (Area 4A)
3.5 acres from Phase 1 of Conservancy at Waxhaw Creek (Area 4B)
Runoff from both of these areas has been included in the storm drainage design and is accounted
for in the post-construction storm water management plan.
On-Site Undisturbed Undetained Drainage Areas
The 53.85-acre project area includes a significant amount of undisturbed land:
10.6 acres along the north side of the property (Area 3A)
9.2 acres along the south side of the property (Area 3B)
0.86 acre at the southeast corner of the property (Area 3C)
Runoff from these areas will not be detained.
Soils
The soils in the project area consist of:
Cecil gravelly sandy clay loams of both CeB2 (2 to 8-percent slopes) and CeC2 (8 to 15-
percent slopes). Cecil clay loams are well-drained and are classified as Hydrologic Soil
Group B. These soils comprise roughly 96 percent of the disturbed area.
Helena fine sandy loam (HeB, 2 to 8 percent slopes). Helena sandy loams are moderately
well-drained and are classified as Hydrologic Soil Group D. These soils comprise less than
one percent of the disturbed area.
Tarrus gravelly silt loam TaD, 15 to 35 percent slopes) Tarrus silt loams are well-drained
and are classified as Hydrologic Soil Group B. These soils comprise less than one percent
of the disturbed area. These soils comprise roughly 3 percent of the disturbed area.
Project Data
Project Name: The Conservancy at Waxhaw Creek Phase 2
Owner/Developer: True Homes
Parcel ID: 05099004A
Project Location: north side of Steele Road (SR 1177), approximately 4400 feet
west of its intersection with Lancaster Highway (NC 200) in Union
County
Latitude 34.859066 Longitude -80.726398
County: Union
Proposed Development: Construction of 36 single-family lots
Scope of Work: Roadway, drainage, home construction
Denuded Area: 25.1 Ac
River Basin: Catawba
Soils: TaD, HeB, CeB2, CeC2
BMP Design
Based on the Site Specific Water Quality Management Plan for the Goose Creek Watershed (NC
15A NCAC 2B .0600-.0609) the project is required to control and treat the difference in the
stormwater runoff from the predevelopment and post-development conditions for the one-year,
24-hour storm.
Surface Area
SA/DA Charts for the Mountains and Piedmont Region (10-2 and 10-3) were used for
determination of the minimum permanent pool surface areas. Average depth used was 3 feet.
Impervious area for the total 53.85-acre project is 8.01 percent.
Minimum Treatment Volume - based on the Simplified Method using assumed 10-percent
impervious area.
Runoff Calculations
Pre and Post-Development peak runoff values were determined based on the time of
concentration
Rainfall data for the Waxhaw area were downloaded from NOAA website: Atlas 14, Volume 2,
Version 3, "Pont Precipitation Frequency Estimates."
Runoff coefficients were determined for each of the two drainage areas. Assumed buildout of
off-site areas were included in the composite runoff coefficient calculation.
Time of concentration for each of the two drainage areas was determined based on hydraulic
path and land use characteristics.
Routing calculations were performed using HydroCAD software utilizing the Rational Method.
Outlet Structure
Outlet structure will be a 5-foot concrete riser that will house the water quality orifice, weirs,
drawdown drain/valve and outflow barrel.
Drawdown
Maintenance for each of the wet-ponds will be facilitated by 8-inch ductile iron pipe drawdown
drain and handwheel -operated valve located in the riser structure.
USGS Map
SITE
BMP‐1
Runoff Coefficient
Runoff 
coeff, c c  x  A
On‐site undist area 1 106,436 sf 2.443 ac
Total undisturbed areas 2.443 ac 0.15 0.37
Impervious areas
Roadway 0.750 ac 0.95 0.71
Buildings & driveways 1.520 ac 0.98 1.49
Pond area 30,624 sf 0.703 ac 0.27 0.19
Lawns (heavy soils) 11.844 ac 0.27 3.20
Total acreage 17.260 ac
Subtotal =  5.96
0.35
TOTAL ON‐SITE IMPERVIOUS AREA = 98,881 sf
TOTAL IMPERVIOUS AREA = 98,881 sf
Rational Method
Description Area
Composite c  = 
BMP‐1 Peak Runoff Rate ‐ Pre‐Dev 
Q = c  x  I  x  A
c = 0.15
Tc = 49.00 min
i = 1.66 in/hr (1‐year, 24‐hr storm for Waxhaw)
A = 17.26 ac
Q =  4.30 cfs (for 1‐year, 24‐hr storm)
BMP‐1 Peak Runoff Rate ‐ Post‐Dev
Q = c  x  I  x  A
c = 0.35
Tc = 19.00 min
i = 2.96 in/hr (1‐year, 24‐hr storm for Waxhaw)
A = 17.26 ac
Q =  17.63 cfs  (for 1‐year, 24‐hr storm)
BMP‐1 Runoff Volume (Simple Method)
Drainage area 17.26 ac
Post Development
I = 10.00% (assumed)
Runoff coefficient, Rv
Rv = 0.05+0.009(I) =0.140 ac‐ft
Ro = 2.95 in
Vol = 3630 x Ro x Rv x A =25,876 cf
Pre‐Development
I = 0.00%
Rv = 0.05+0.009(I) =0.05 ac‐ft
Ro = 2.95 in
Vol = 3630 x Ro x Rv x A =9,241 cf
Volume to control 16,635 cf
Drainage area = 17.26 ac
From Table 10‐3 , SA/DA = 0.0059
for average depth of 3.0 ft and 10% impervious cover
Min. perm pool surface area  =  17.26  x  43,560  x  0.0059
= 4,436 sf
Actual perm pool surface area = 15,498 sf
Average depth calculation 
Area (sf) Elevation
Area bot shelf  = 14,518 521.50
Area perm pool  = 16,158 522.00
Area bot pond  = 8,311 518.00
Depth  = 3.5
Average depth = 3.23 ft   (Equation 3)
BMP‐1
Stage/Storage
Main Pond
Elev Area Vol
518.0 7,463
520.0 9,470 16933
521.5 11,123 15,445
522.0 12,198 5,830
Main pond volume 38,208 cf
Forebay
518.0 848
520.0 1,564 2,412
521.0 2,420 1,992
521.5 2,757 1,294
522.0 3,300 1,514
Forebay volume 7,213 cf
Total volume 45,421 cf
Forebay percentage 18.9%
TOTAL CONTOUR AREAS
518.0 8,311
520.0 11,034
521.5 13,880
522.0 15,498
522.5 17,206
523.0 18,303
524.0 21,531 15302
526.6 11,939
528.0 23,278
OUTLETS
520.00 18" culvert
522.00 2" orifice
523.40 8' weir
523.90 16' weir
524.00 20' emergency spillway
SA/DA = 0.0059 (from 2016 manual)
SA = 4,437 sf
permanent pool elevation 522.00
temporary pool elevation 523.42 4538
area at temp pool elevation 20,404 sf 4973
area at perm pool elevation 15,498 sf
average area 17,951 sf
temporary pool depth 1.42 ft
volume temporary pool 25,490 cf
BMP‐1 Drawdown Calculations
2‐in orifice invert elev (PPE) 522.00
centroid of orifice elev 522.00 (orifice in horizontal plane)
temp pool elevation (add'l vol) 523.42 A = 0.021806 sf
coefficient of discharge, C = 0.60
Head on orifice, H  = 1.42 ft
Driving head, Ho = H/3  = 0.47 ft
Q =  C x A x SQRT (2gHo) 30.48267
= 0.07 cfs 5.521111
Drawdown time 98 hours
4.08 days
BMP‐2
Runoff Coefficient/Curve Number
Runoff 
coeff, c c  x  A
Off‐site 
Off‐site undev area  138,329 sf 3.18 ac 0.47 * 1.49
*assume fully developed: 25% impervious, remaining area lawn
Impervious area = 0.79 ac
2.39 COMPOSITE C  = 0.47
Phase 1 area draining to site 3.54 ac
Impervious area
566 LF rdwy  x 9' =8,490 sf
3 lots @ 4177 sf ea =12,531 sf
21,021 sf 0.483 ac 0.95 0.46
Remaining pervious area 3.06 ac
Assume 30% undisturbed wooded 0.92 ac 0.918 ac 0.15 0.14
70% lawns 2.14 ac 2.142 ac 0.20 0.43
1.02
2.14 COMPOSITE C  = 0.29
On‐Site
On‐site undist area 1 146,053 sf 3.67 ac
On‐site undist area 2 34,494 sf 0.79 ac
Total on‐site undisturbed areas 4.462 ac 0.15 0.67
Impervious area (on‐site) 4.35 ac
Roadway 1.446 ac 0.95 1.37
Homes & driveways 2.900 ac 0.95 2.75
Pond area 30,624 sf 0.703 ac 0.20 0.14
Lawns (heavy soils)  6.35 ac
60%  5‐7 percent slopes 3.812 ac 0.30 1.14
40%  2‐5 percent slopes 2.541 ac 0.20 0.51
Total acreage 22.58 ac
Subtotal =  9.11
0.40
TOTAL ON‐SITE IMPERVIOUS AREA = 189,307 sf
TOTAL IMPERVIOUS AREA = 244,910 sf
Area
Composite c  = 
Description
Rational Method
BMP‐2 Peak Runoff Rate ‐ Pre‐Dev 
Q = c  x  I  x  A
c = 0.15
Tc = 35.00 min
I = 2.09 in/hr (1‐year, 24‐hr storm for Waxhaw)
A = 22.58 ac
Q =  7.08 cfs
BMP‐2 Peak Runoff Rate ‐ Post‐Dev
Q = c  x  I  x  A
c = 0.41
Tc = 29.00 min
I = 2.74 in/hr (1‐year, 24‐hr storm for Waxhaw)
A = 22.58 ac
Q =  25.37 cfs
BMP‐2 Runoff Volume (Simple Method)
Drainage area (on‐site only) 15.86 ac
Drainage area (total) 22.58 ac 15.86
Impervious area (on‐site) 4.35 ac
Impervious area (total) 6.72 ac
Post Development
I = 10.00% (assumed)
Runoff coefficient, Rv
Rv = 0.05+0.009(I) =0.140 ac‐ft
Ro = 2.95 in
Vol = 3630 x Ro x Rv x A =33,852 cf
Pre‐Development
I = 0.00%
Rv = 0.05+0.009(I) =0.05 ac‐ft
Ro = 2.95 in
Vol = 3630 x Ro x Rv x A =12,090 cf
Volume to control 21,762 cf
Drainage area (on‐site) = 15.86 ac
Off‐site drainage area = 6.72 ac
Total drainage area = 22.58 ac
From Table 10‐1 , SA/DA = 0.0059
for average depth of 3.0 ft and 10% impervious cover
Min. perm pool surface area  =  22.58  x  43,560  x  0.0059
= 5,803 sf
Actual perm pool surface area = 9,206 sf
Average depth calculation 
Area (sf) Elevation
Area bot shelf  = 7,893 546.00
Area perm pool  = 9,206 546.50
Area bot pond  = 3,378 542.00
Depth  = 4.0 ft
Average depth = 3.32 ft (Equation 3)
BMP‐2
Stage/Storage
Main pond
Elev Area Vol
542.0 3,088
544.0 4,652 7,740
546.0 6,358 11,010
546.5 7,271 3,407
Main pond volume 22,157 cf
Forebay
542.0 290
544.0 816 1,106
546.0 1535 2,351
546.5 1935 868
Forebay volume 4,325 cf
Total volume 26,482 cf
19.5%
TOTAL CONTOUR AREAS
542.0 3,378
544.0 5,468
546.0 7,893
546.5 9,206
547.0 10,776
548.0 12,770
549.0 14,265
550.0 15,834
551.0 17,445
552.0 19,319
SA/DA 0.0059 (from 2016 manual)
SA = 5,803 sf
permanent pool elevation 546.50
temporary pool elevation 549.44
area at temp pool elevation 14,941 sf
area at perm pool elevation 9,206 sf
average area 12,074 sf
temporary pool depth 2.94 ft
volume temporary pool (design vol) 35,496 cf
Forebay percentage
BMP‐2 Drawdown Calculations
orifice invert elev 546.50
centroid of orifice elev 546.50 (orifice in horizontal plane)
temp pool elevation (add'l vol) 549.44 A = 0.034071 sf
orifice diameter 2.50 in
coefficient of discharge, C = 0.60
Head on orifice, H  = 2.94 ft
Driving head, Ho =  H/3  = 0.98 ft
Q =  C x A x SQRT (2gHo) 63.112
= 0.16 cfs 7.944306
Drawdown time 49 hours
2.05 days
Attachment to Form SW401 Part II page 2 of 2
Lot Built‐Upon Areas Rev 04‐25‐20
Conservancy at Waxhaw Creek Phase 2
L1 L2 L3 A1 A2 A3 Total 
39 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
40 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
41 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
42 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
43 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
44 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
45 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
75 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
74 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
73 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
72 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
71 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
70 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
69 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
68 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
67 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
66 60.94 31.83 23.11 277.32 572.94 90.00 940.26 3340.26
65 60.94 31.83 23.11 277.32 572.94 90.00 940.26 3340.26
64 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
63 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
62 59.41 31.83 21.58 258.96 572.94 90.00 921.90 3321.90
61 70.78 31.83 32.95 395.40 572.94 90.00 1058.34 3458.34
60 67.92 31.83 30.09 361.08 572.94 90.00 1024.02 3424.02
59 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
58 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
57 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
56 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
55 125.62 24.15 95.47 1145.64 434.70 90.00 1670.34 4070.34
54 121.73 31.83 83.90 1006.80 572.94 90.00 1669.74 4069.74
53 117.87 31.83 80.04 960.48 572.94 90.00 1623.42 4023.42
52 121.01 31.83 83.18 998.16 572.94 90.00 1661.10 4061.10
51 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
50 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
49 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
48 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
47 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
46 60.00 31.83 22.17 266.04 572.94 90.00 928.98 3328.98
37,521 126,321
Driveway Lengths Driveway Areas Lot BUA
(Bldg+DW)
Lot 
No.
TOTAL SF
Attachment to Form SW401 Part II page 1 of 2
Built‐Upon Area Rev 04‐25‐20
Conservancy at Waxhaw Creek Phase 2
SA Site area 53.85 ac            = 2,345,706 sf
DF Density factor 12 %
RA Road area 62,986 sf
OA Other area
Total allowable lot BUA  = SA  x  DF  ‐  RA  ‐  OA
= 218,499 sf
Total BUA on lots from lot listing (page 2): 126,321 sf
BUA outside lots (streets) 62,986 sf
Total on‐site BUA 189,307
Maximum Allowable BUA
TOTAL SITE 2,345,706 sf
12% BUA 281,485 sf
LESS STREETS 62,986
 MAX TOTAL LOT BUA 218,499 sf
NUMBER OF LOTS 37
MAX ALLOW BUA PER LOT 5,905 sf
Attachment to Form SWU‐101 Part IV Item 11 page 1 of 1
Impervious Surface Areas Rev 04‐25‐20
Conservancy at Waxhaw Creek Phase 2
On‐site BUA:
On‐site Buildings: 37  x  2,400 sf ea  = 88,800 sf
On‐site Streets: from AutoCAD drawing 62,986 sf
On‐site parking (driveways): from lot BUA summary: 37,521 sf
On‐site subtotal 189,307 sf
Off‐site BUA: (BMP‐2)
1. Off‐site undeveloped area 3.18 ac
assume fully developed: 25% impervious, remaining area lawn
Impervious area =0.25  x  3.18 ac  = 0.79 ac
34,582 sf 34,582 sf
2. Phase 1 area draining to site 3.54 ac 154,202 sf
Impervious areas
566 LF roadway  x 9' =8,490 sf
3 lots @ 4177 sf ea =12,531 sf
21,021 sf 21,021 sf
Off‐site impervious area subtotal 55,603 sf
Total impervious area 244,910 sf
PROJECT: Conservancy at Waxhaw Creek Phase 2 BY: RLM
PROJECT. NO.: 16079
DATE: 09/09/16
TIME OF CONCENTRATION: BMP-1 (PRE-DEVELOPMENT)
SHEET FLOW:
Surface Description =unpaved
Manning's Roughness (n) =0.40
Flow Length (ft) = 300 585.0
P2 (in.) =3.56 575.8 0.0306
Slope (%) =3.06 9.2
T(t) (min.) =41.36
SHALLOW CONCENTRATED FLOW:
Surface Description unpaved
Flow Length (ft) =357 575.8
Water Course Slope (ft/ft) =0.027 566.1 0.0271
Average Velocity (fps) =2.66 9.7
T(t) (min.) =2.24
SHALLOW CONCENTRATED FLOW:
Surface Description unpaved
Flow Length (ft) =1055 566.1
Water Course Slope (ft/ft) =0.044 519.4 0.0444
Average Velocity (fps) =3.40 46.8
T(t) (min.) =5.17
SUM OF TRAVEL TIMES =48.8 minutes
USE TIME OF CONCENTRATION OF 49.0 minutes
0.817 hours
Flow Length 1,712
Fall 65.7
PROJECT: Conservancy at Waxhaw Creek Phase 2 BY: RLM
PROJECT. NO.: 16079
DATE: 09/09/16
TIME OF CONCENTRATION: BMP-1 (POST DEVELOPMENT)
SHEET FLOW:
Surface Description =unpaved
Manning's Roughness (n) =0.40
Flow Length (ft) = 100 585.0
P2 (in.) =3.56 580.5 0.0454
Slope (%) =4.54 4.5
T(t) (min.) =14.67
SHALLOW CONCENTRATED FLOW:
Surface Description unpaved
Flow Length (ft) =354 580.5
Water Course Slope (ft/ft) =0.06 558.8 0.0612
Average Velocity (fps) =3.99 21.7
T(t) (min.) =1.48
PIPE FLOW:
Pipe Size (in.) =18 558.8
Pipe Area (sq.ft.) =1.77 555.5
Hydraulic Radius =0.375 3.3
Pipe Slope (%) =6.9
Manning's Coefficient (n) =0.012
Velocity (fps) =16.93
Flow Length (ft) =48
T(t) (min.) =0.05
PIPE FLOW:
Pipe Size (in.) =18 555.5
Pipe Area (sq.ft.) =1.77 554.0
Hydraulic Radius =0.375 1.5
Pipe Slope (%) =0.8
Manning's Coefficient (n) =0.012
Velocity (fps) =5.71
Flow Length (ft) =192
T(t) (min.) =0.56
SHALLOW CONCENTRATED FLOW:
Surface Description unpaved
Flow Length (ft) =226 554.0
Water Course Slope (ft/ft) =0.052 542.2 0.0522
Average Velocity (fps) =3.69 11.8
T(t) (min.) =1.02
CHANNEL FLOW:
Channel Area (sf) =4.00 Bottom Width (ft) = 2 542.2
Hydraulic Radius =0.618 Side Slope (ft) = 2 535.0
Channel Slope (%) = 5.143 Depth (ft) = 1 7.2
Manning's Coefficient (n) = 0.03
Velocity (fps) =8.17
Flow Length (ft) = 140
T(t) (min.) =0.29
PIPE FLOW:
Pipe Size (in.) = 30 535.0
Pipe Area (sq.ft.) =4.91 525.5
Hydraulic Radius =0.625 9.5
Pipe Slope (%) = 5.2
Manning's Coefficient (n) = 0.012
Velocity (fps) =20.62
Flow Length (ft) = 184
T(t) (min.) =0.15
PIPE FLOW:
Pipe Size (in.) = 30 525.5
Pipe Area (sq.ft.) =4.91 525.3
Hydraulic Radius =0.63 0.2
Pipe Slope (%) = 0.5
Manning's Coefficient (n) = 0.012
Velocity (fps) =6.60
Flow Length (ft) = 42
T(t) (min.) =0.11
PIPE FLOW:
Pipe Size (in.) = 30 525.3
Pipe Area (sq.ft.) =4.91 524.0
Hydraulic Radius =0.63 1.3
Pipe Slope (%) = 0.8
Manning's Coefficient (n) = 0.012
Velocity (fps) =8.01
Flow Length (ft) = 166
T(t) (min.) =0.35
SUM OF TRAVEL TIMES = 18.66 minutes
USE TIME OF CONCENTRATION OF 19.0 minutes
1452 ft
PROJECT: Conservancy at Waxhaw Creek Phase 2 BY: RLM
PROJECT. NO.: 16079
DATE: 09/09/16
TIME OF CONCENTRATION: BMP-2 (PRE-DEVELOPMENT)
SHEET FLOW:
Surface Description =unpaved
Manning's Roughness (n) = 0.40
Flow Length (ft) = 300 655.0
P2 (in.) =3.56 633.8 0.0706667
Slope (%) =7.07 21.2
T(t) (min.) =29.6
SHALLOW CONCENTRATED FLOW:
Surface Description unpaved
Flow Length (ft) =545 633.8
Water Course Slope (ft/ft) = 0.066 598.0 0.0656881
Average Velocity (fps) =4.14 35.8
T(t) (min.) =2.2
CHANNEL FLOW:
Channel Area (sf) =2.63 Bottom Width (ft) = 0 598.00
Hydraulic Radius =0.249 Side Slope (ft) = 10.5 566.04
Channel Slope (%) =12.533 Depth (ft) = 0.5
Manning's Coefficient (n) = 0.035
Velocity (fps) =5.96 15.7
Flow Length (ft) =255
T(t) (min.) =0.7
CHANNEL FLOW:
Channel Area (sf) =8.25 Bottom Width (ft) = 10 566.0
Hydraulic Radius =0.358 Side Slope (ft) = 13 552.0
Channel Slope (%) =4.961 Depth (ft) = 0.5
Manning's Coefficient (n) = 0.035
Velocity (fps) =4.78 39.4
Flow Length (ft) =284
T(t) (min.) =1.0
SHALLOW CONCENTRATED FLOW:
Surface Description unpaved
Flow Length (ft) =210 552.0
Water Course Slope (ft/ft) = 0.049 541.7 0.0488095
Average Velocity (fps) =3.56 10.3
T(t) (min.) =1.0
SUM OF TRAVEL TIMES = 34.5 minutes
USE TIME OF CONCENTRATION OF 35.0 minutes
PROJECT: Conservancy at Waxhaw Creek Phase 2 BY: RLM
PROJECT. NO.: 16079
DATE: 09/09/16
TIME OF CONCENTRATION: BMP-2 (POST DEVELOPED)
SHEET FLOW:
Surface Description =unpaved ASSUMED FULL DEV
Manning's Roughness (n) =0.400
Flow Length (ft) = 100 655.0
P2 (in.) =3.56 652.2 0.0279
Slope (%) =2.79 2.8
T(t) (min.) =17.8
SHALLOW CONCENTRATED FLOW:
Surface Description unpaved
Flow Length (ft) =305 652.2
Water Course Slope (ft/ft) =0.08 627.0 0.0827
Average Velocity (fps) =4.64 25.2
T(t) (min.) =1.1
CHANNEL FLOW:
Channel Area (sf) =2.00 Bottom Width (ft) = 0 627.0
Hydraulic Radius =0.447 Side Slope (ft) = 2 597.7
Channel Slope (%) =6.143 Depth (ft) =1
Manning's Coefficient (n) =0.03
Velocity (fps) =7.20
Flow Length (ft) =477
T(t) (min.) =1.1
PIPE FLOW:
Pipe Size (in.) =24 597.7
Pipe Area (sq.ft.) =3.14 596.7
Hydraulic Radius =0.5 1.0
Pipe Slope (%) =1.0
Manning's Coefficient (n) =0.012
Velocity (fps) =7.82
Flow Length (ft) =80
T(t) (min.) =0.2
CHANNEL FLOW:
Channel Area (sf) =3.00 Bottom Width (ft) = 0 596.7
Hydraulic Radius =0.474 Side Slope (ft) = 3 563.2
Channel Slope (%) =5.889 Depth (ft) =1
Manning's Coefficient (n) =0.03
Velocity (fps) =7.33
Flow Length (ft) =569
T(t) (min.) =1.3
PIPE FLOW:
Pipe Size (in.) = 36 563.2
Pipe Area (sq.ft.) =7.07 559.72
Hydraulic Radius =0.75 3.5
Pipe Slope (%) = 3.5
Manning's Coefficient (n) = 0.012
Velocity (fps) =19.09
Flow Length (ft) = 88
T(t) (min.) =0.1
SHALLOW CONCENTRATED FLOW:
Surface Description unpaved
Flow Length (ft) = 90 559.7
Water Course Slope (ft/ft) = 0.019 558.0 0.0191
Average Velocity (fps) =2.23 1.7
T(t) (min.) =0.7
SUM OF TRAVEL TIMES = 22.2 minutes
USE TIME OF CONCENTRATION OF 22.0 minutes
1709 ft
HYDROCAD REPORTS
PRE-DEVELOPMENT
HYDROGRAPHS
Waxhaw 2-yr Duration=19 min, Inten=3.52 in/hrConservancy Ph 2 BMP-1 Extended Det
Printed 4/28/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
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This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Summary for Subcatchment 3S: Pre-Dev
Runoff =3.53 cfs @ 0.32 hrs, Volume=0.093 af, Depth=0.06"
Runoff by Rational method, Rise/Fall=1.0/1.0 xTc, Time Span= 0.00-120.00 hrs, dt= 0.01 hrs
Waxhaw 2-yr Duration=19 min, Inten=3.52 in/hr
Area (ac)C Description
17.260 0.15
17.260 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min)(feet)(ft/ft)(ft/sec)(cfs)
49.0 Direct Entry,
Waxhaw 25-yr Duration=19 min, Inten=5.13 in/hrConservancy Ph 2 BMP-1 Extended Det
Printed 4/28/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 2HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Summary for Subcatchment 3S: Pre-Dev
Runoff =5.15 cfs @ 0.32 hrs, Volume=0.136 af, Depth=0.09"
Runoff by Rational method, Rise/Fall=1.0/1.0 xTc, Time Span= 0.00-120.00 hrs, dt= 0.01 hrs
Waxhaw 25-yr Duration=19 min, Inten=5.13 in/hr
Area (ac)C Description
17.260 0.15
17.260 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min)(feet)(ft/ft)(ft/sec)(cfs)
49.0 Direct Entry,
Waxhaw 50-yr Duration=19 min, Inten=5.51 in/hrConservancy Ph 2 BMP-1 Extended Det
Printed 4/28/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 3HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Summary for Subcatchment 3S: Pre-Dev
Runoff =5.53 cfs @ 0.32 hrs, Volume=0.146 af, Depth=0.10"
Runoff by Rational method, Rise/Fall=1.0/1.0 xTc, Time Span= 0.00-120.00 hrs, dt= 0.01 hrs
Waxhaw 50-yr Duration=19 min, Inten=5.51 in/hr
Area (ac)C Description
17.260 0.15
17.260 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min)(feet)(ft/ft)(ft/sec)(cfs)
49.0 Direct Entry,
Waxhaw 2-yr Duration=22 min, Inten=3.26 in/hrConservancy Ph 2 BMP-2 Extended Det
Printed 4/28/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 1HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Summary for Subcatchment 3S: Pre-Dev
Runoff =7.04 cfs @ 0.37 hrs, Volume=0.215 af, Depth=0.11"
Runoff by Rational method, Rise/Fall=1.0/1.0 xTc, Time Span= 0.00-120.00 hrs, dt= 0.01 hrs
Waxhaw 2-yr Duration=22 min, Inten=3.26 in/hr
Area (ac)C Description
22.580 0.15
22.580 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min)(feet)(ft/ft)(ft/sec)(cfs)
34.5 Direct Entry,
Waxhaw 25-yr Duration=22 min, Inten=4.82 in/hrConservancy Ph 2 BMP-2 Extended Det
Printed 4/28/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 2HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Summary for Subcatchment 3S: Pre-Dev
Runoff =10.41 cfs @ 0.37 hrs, Volume=0.318 af, Depth=0.17"
Runoff by Rational method, Rise/Fall=1.0/1.0 xTc, Time Span= 0.00-120.00 hrs, dt= 0.01 hrs
Waxhaw 25-yr Duration=22 min, Inten=4.82 in/hr
Area (ac)C Description
22.580 0.15
22.580 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min)(feet)(ft/ft)(ft/sec)(cfs)
34.5 Direct Entry,
Waxhaw 50-yr Duration=22 min, Inten=5.19 in/hrConservancy Ph 2 BMP-2 Extended Det
Printed 4/28/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 3HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Summary for Subcatchment 3S: Pre-Dev
Runoff =11.21 cfs @ 0.37 hrs, Volume=0.342 af, Depth=0.18"
Runoff by Rational method, Rise/Fall=1.0/1.0 xTc, Time Span= 0.00-120.00 hrs, dt= 0.01 hrs
Waxhaw 50-yr Duration=22 min, Inten=5.19 in/hr
Area (ac)C Description
22.580 0.15
22.580 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min)(feet)(ft/ft)(ft/sec)(cfs)
34.5 Direct Entry,
POST-DEVELOPMENT
HYDROGRAPHS
1-YEAR 24-HOUR
Type II 24-hr 1-Year Rainfall=3.00"Conservancy Ph 2 BMP-1 SCS
Printed 4/26/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 1HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Summary for Pond 2P: P1
Inflow Area =17.260 ac,13.15% Impervious, Inflow Depth = 0.51" for 1-Year event
Inflow =7.49 cfs @ 12.16 hrs, Volume=0.728 af
Outflow =0.27 cfs @ 23.62 hrs, Volume=0.714 af, Atten= 96%, Lag= 687.6 min
Primary =0.27 cfs @ 23.62 hrs, Volume=0.714 af
Secondary =0.00 cfs @ 5.00 hrs, Volume=0.000 af
Routing by Stor-Ind method, Time Span= 5.00-120.00 hrs, dt= 0.05 hrs / 3
Starting Elev= 522.00' Surf.Area= 15,498 sf Storage= 45,790 cf
Peak Elev= 523.42' @ 23.62 hrs Surf.Area= 19,652 sf Storage= 71,233 cf (25,443 cf above start)
Plug-Flow detention time= (not calculated: initial storage exceeds outflow)
Center-of-Mass det. time= 2,171.5 min ( 3,083.6 - 912.0 )
Volume Invert Avail.Storage Storage Description
#1 518.00'172,455 cf Custom Stage Data (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet)(sq-ft)(cubic-feet)(cubic-feet)
518.00 8,311 0 0
520.00 11,304 19,615 19,615
521.50 13,822 18,845 38,460
522.00 15,498 7,330 45,790
522.50 17,358 8,214 54,004
523.00 18,305 8,916 62,919
524.00 21,531 19,918 82,837
528.00 23,278 89,618 172,455
Device Routing Invert Outlet Devices
#1 Primary 520.00'18.0" Round Culvert L= 40.0' Ke= 0.500
Inlet / Outlet Invert= 520.00' / 519.75' S= 0.0063 '/' Cc= 0.900
n= 0.012, Flow Area= 1.77 sf
#2 Device 1 522.00'2.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Secondary 524.00'20.0' long x 8.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00 3.50 4.00 4.50 5.00 5.50
Coef. (English) 2.43 2.54 2.70 2.69 2.68 2.68 2.66 2.64 2.64
2.64 2.65 2.65 2.66 2.66 2.68 2.70 2.74
#4 Device 1 523.40'8.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
#5 Device 1 523.90'16.0' long x 1.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00
Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31
3.30 3.31 3.32
Type II 24-hr 1-Year Rainfall=3.00"Conservancy Ph 2 BMP-1 SCS
Printed 4/26/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
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educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Primary OutFlow Max=0.19 cfs @ 23.62 hrs HW=523.42' (Free Discharge)
1=Culvert (Passes 0.19 cfs of 13.90 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.13 cfs @ 5.73 fps)
4=Sharp-Crested Rectangular Weir (Weir Controls 0.06 cfs @ 0.43 fps)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 5.00 hrs HW=522.00' (Free Discharge)
3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Type II 24-hr 1-Year Rainfall=3.00"Conservancy Ph 2 BMP-1 SCS
Printed 4/26/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
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This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
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HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Hydrograph for Pond 2P: P1
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Outflow
(cfs)
Primary
(cfs)
Secondary
(cfs)
5.00 0.00 45,790 522.00 0.00 0.00 0.00
10.00 0.00 45,790 522.00 0.00 0.00 0.00
15.00 0.64 64,212 523.06 0.11 0.11 0.00
20.00 0.31 70,054 523.36 0.12 0.12 0.00
25.00 0.00 70,805 523.40 0.12 0.12 0.00
30.00 0.00 68,617 523.29 0.12 0.12 0.00
35.00 0.00 66,517 523.18 0.11 0.11 0.00
40.00 0.00 64,508 523.08 0.11 0.11 0.00
45.00 0.00 62,589 522.98 0.10 0.10 0.00
50.00 0.00 60,766 522.88 0.10 0.10 0.00
55.00 0.00 59,044 522.78 0.09 0.09 0.00
60.00 0.00 57,422 522.69 0.09 0.09 0.00
65.00 0.00 55,900 522.61 0.08 0.08 0.00
70.00 0.00 54,479 522.53 0.08 0.08 0.00
75.00 0.00 53,159 522.45 0.07 0.07 0.00
80.00 0.00 51,949 522.37 0.06 0.06 0.00
85.00 0.00 50,847 522.31 0.06 0.06 0.00
90.00 0.00 49,855 522.25 0.05 0.05 0.00
95.00 0.00 48,972 522.19 0.05 0.05 0.00
100.00 0.00 48,201 522.15 0.04 0.04 0.00
105.00 0.00 47,539 522.11 0.03 0.03 0.00
110.00 0.00 47,006 522.07 0.02 0.02 0.00
115.00 0.00 46,635 522.05 0.02 0.02 0.00
120.00 0.00 46,377 522.04 0.01 0.01 0.00
Type II 24-hr 1-Year Rainfall=3.00"Conservancy Ph 2 BMP-2 SCS
Printed 4/25/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
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This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Summary for Subcatchment 1S: Post-Dev
Runoff =12.07 cfs @ 12.19 hrs, Volume=1.179 af, Depth=0.63"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 2.00-50.00 hrs, dt= 0.05 hrs
Type II 24-hr 1-Year Rainfall=3.00"
Area (ac)CN Description
*0.793 98 Off-site undeveloped (future 25% impervious)
*2.381 61 Off-site undeveloped (future 75% lawn)
*0.482 98 Off-site Ph 1 area - impervious
*2.142 60 Off-site Ph 1 area - lawn (2-5%)
*0.918 55 Off-site Ph 1 area - undisturbed (wooded)
*4.462 55 On-site undisturbed (wooded)
*1.446 98 On-site - roadway
*2.900 98 On-site - buildings & drives
*0.703 60 On-site pond area
*2.541 60 On-site - lawns (heavy soils) (2-5% slopes)
*3.812 60 On-site - lawns (heavy soil (5-7% slopes)
22.580 68 Weighted Average
17.554 77.74% Pervious Area
5.026 22.26% Impervious Area
Tc Length Slope Velocity Capacity Description
(min)(feet)(ft/ft)(ft/sec)(cfs)
17.8 100 0.0279 0.09 Sheet Flow,
n= 0.400 P2= 3.56"
1.1 305 0.0827 4.63 Shallow Concentrated Flow,
Unpaved Kv= 16.1 fps
1.1 477 0.0610 7.12 14.25 Channel Flow,
Area= 2.0 sf Perim= 4.5' r= 0.44' n= 0.030
0.2 80 0.0100 7.80 24.51 Pipe Channel,
24.0" Round Area= 3.1 sf Perim= 6.3' r= 0.50'
n= 0.012
1.3 576 0.0590 7.34 22.01 Channel Flow,
Area= 3.0 sf Perim= 6.3' r= 0.48' n= 0.030
0.1 88 0.0350 19.12 135.18 Pipe Channel,
36.0" Round Area= 7.1 sf Perim= 9.4' r= 0.75'
n= 0.012
0.7 90 0.0190 2.22 Shallow Concentrated Flow,
Unpaved Kv= 16.1 fps
22.3 1,716 Total
Type II 24-hr 1-Year Rainfall=3.00"Conservancy Ph 2 BMP-2 SCS
Printed 4/25/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
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educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Hydrograph for Subcatchment 1S: Post-Dev
Time
(hours)
Precip.
(inches)
Excess
(inches)
Runoff
(cfs)
2.00 0.07 0.00 0.00
3.00 0.10 0.00 0.00
4.00 0.14 0.00 0.00
5.00 0.19 0.00 0.00
6.00 0.24 0.00 0.00
7.00 0.30 0.00 0.00
8.00 0.36 0.00 0.00
9.00 0.44 0.00 0.00
10.00 0.54 0.00 0.00
11.00 0.71 0.00 0.00
12.00 1.99 0.19 4.54
13.00 2.32 0.31 2.22
14.00 2.46 0.37 1.26
15.00 2.56 0.41 0.98
16.00 2.64 0.45 0.79
17.00 2.71 0.48 0.68
18.00 2.76 0.51 0.61
19.00 2.81 0.53 0.54
20.00 2.86 0.55 0.47
21.00 2.89 0.57 0.43
22.00 2.93 0.59 0.42
23.00 2.97 0.61 0.41
24.00 3.00 0.63 0.39
25.00 3.00 0.63 0.00
26.00 3.00 0.63 0.00
27.00 3.00 0.63 0.00
28.00 3.00 0.63 0.00
29.00 3.00 0.63 0.00
30.00 3.00 0.63 0.00
31.00 3.00 0.63 0.00
32.00 3.00 0.63 0.00
33.00 3.00 0.63 0.00
34.00 3.00 0.63 0.00
35.00 3.00 0.63 0.00
36.00 3.00 0.63 0.00
37.00 3.00 0.63 0.00
38.00 3.00 0.63 0.00
39.00 3.00 0.63 0.00
40.00 3.00 0.63 0.00
41.00 3.00 0.63 0.00
42.00 3.00 0.63 0.00
43.00 3.00 0.63 0.00
44.00 3.00 0.63 0.00
45.00 3.00 0.63 0.00
46.00 3.00 0.63 0.00
47.00 3.00 0.63 0.00
Time
(hours)
Precip.
(inches)
Excess
(inches)
Runoff
(cfs)
48.00 3.00 0.63 0.00
49.00 3.00 0.63 0.00
50.00 3.00 0.63 0.00
Type II 24-hr 1-Year Rainfall=3.00"Conservancy Ph 2 BMP-2 SCS
Printed 4/25/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 3HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Summary for Subcatchment 3S: Pre-Dev
Runoff =1.11 cfs @ 12.54 hrs, Volume=0.367 af, Depth=0.19"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 2.00-50.00 hrs, dt= 0.05 hrs
Type II 24-hr 1-Year Rainfall=3.00"
Area (ac)CN Description
*22.580 55
22.580 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min)(feet)(ft/ft)(ft/sec)(cfs)
34.5 Direct Entry,
Type II 24-hr 1-Year Rainfall=3.00"Conservancy Ph 2 BMP-2 SCS
Printed 4/25/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 4HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Hydrograph for Subcatchment 3S: Pre-Dev
Time
(hours)
Precip.
(inches)
Excess
(inches)
Runoff
(cfs)
2.00 0.07 0.00 0.00
3.00 0.10 0.00 0.00
4.00 0.14 0.00 0.00
5.00 0.19 0.00 0.00
6.00 0.24 0.00 0.00
7.00 0.30 0.00 0.00
8.00 0.36 0.00 0.00
9.00 0.44 0.00 0.00
10.00 0.54 0.00 0.00
11.00 0.71 0.00 0.00
12.00 1.99 0.01 0.02
13.00 2.32 0.05 0.84
14.00 2.46 0.08 0.54
15.00 2.56 0.09 0.42
16.00 2.64 0.11 0.36
17.00 2.71 0.12 0.32
18.00 2.76 0.14 0.29
19.00 2.81 0.15 0.27
20.00 2.86 0.16 0.23
21.00 2.89 0.17 0.21
22.00 2.93 0.18 0.21
23.00 2.97 0.19 0.21
24.00 3.00 0.19 0.20
25.00 3.00 0.19 0.01
26.00 3.00 0.19 0.00
27.00 3.00 0.19 0.00
28.00 3.00 0.19 0.00
29.00 3.00 0.19 0.00
30.00 3.00 0.19 0.00
31.00 3.00 0.19 0.00
32.00 3.00 0.19 0.00
33.00 3.00 0.19 0.00
34.00 3.00 0.19 0.00
35.00 3.00 0.19 0.00
36.00 3.00 0.19 0.00
37.00 3.00 0.19 0.00
38.00 3.00 0.19 0.00
39.00 3.00 0.19 0.00
40.00 3.00 0.19 0.00
41.00 3.00 0.19 0.00
42.00 3.00 0.19 0.00
43.00 3.00 0.19 0.00
44.00 3.00 0.19 0.00
45.00 3.00 0.19 0.00
46.00 3.00 0.19 0.00
47.00 3.00 0.19 0.00
Time
(hours)
Precip.
(inches)
Excess
(inches)
Runoff
(cfs)
48.00 3.00 0.19 0.00
49.00 3.00 0.19 0.00
50.00 3.00 0.19 0.00
Type II 24-hr 1-Year Rainfall=3.00"Conservancy Ph 2 BMP-2 SCS
Printed 4/25/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 5HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Summary for Pond 2P: P1
Inflow Area =22.580 ac,22.26% Impervious, Inflow Depth = 0.63" for 1-Year event
Inflow =12.07 cfs @ 12.19 hrs, Volume=1.179 af
Outflow =0.28 cfs @ 24.24 hrs, Volume=0.771 af, Atten= 98%, Lag= 723.0 min
Primary =0.28 cfs @ 24.24 hrs, Volume=0.771 af
Secondary =0.00 cfs @ 2.00 hrs, Volume=0.000 af
Routing by Stor-Ind method, Time Span= 2.00-50.00 hrs, dt= 0.05 hrs / 3
Starting Elev= 546.50' Surf.Area= 9,206 sf Storage= 29,037 cf
Peak Elev= 549.45' @ 24.24 hrs Surf.Area= 14,964 sf Storage= 68,866 cf (39,830 cf above start)
Plug-Flow detention time= 2,092.7 min calculated for 0.104 af (9% of inflow)
Center-of-Mass det. time= 916.6 min ( 1,817.7 - 901.2 )
Volume Invert Avail.Storage Storage Description
#1 542.00'112,234 cf Custom Stage Data (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet)(sq-ft)(cubic-feet)(cubic-feet)
542.00 4,488 0 0
546.00 7,893 24,762 24,762
546.50 9,206 4,275 29,037
547.00 12,770 5,494 34,531
548.00 14,115 13,443 47,973
549.00 14,265 14,190 62,163
550.00 15,834 15,050 77,213
551.00 17,445 16,640 93,852
552.00 19,319 18,382 112,234
Device Routing Invert Outlet Devices
#1 Primary 542.00'18.0" Round Culvert L= 48.0' Ke= 0.500
Inlet / Outlet Invert= 542.00' / 541.00' S= 0.0208 '/' Cc= 0.900
n= 0.012, Flow Area= 1.77 sf
#2 Device 1 546.50'2.5" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Secondary 551.00'20.0' long x 8.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00 3.50 4.00 4.50 5.00 5.50
Coef. (English) 2.43 2.54 2.70 2.69 2.68 2.68 2.66 2.64 2.64
2.64 2.65 2.65 2.66 2.66 2.68 2.70 2.74
#4 Device 1 549.80'8.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
#5 Device 1 550.30'16.0' long x 1.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00
Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31
Type II 24-hr 1-Year Rainfall=3.00"Conservancy Ph 2 BMP-2 SCS
Printed 4/25/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 6HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
3.30 3.31 3.32
Primary OutFlow Max=0.28 cfs @ 24.24 hrs HW=549.45' (Free Discharge)
1=Culvert (Passes 0.28 cfs of 22.02 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.28 cfs @ 8.26 fps)
4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 2.00 hrs HW=546.50' (Free Discharge)
3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Type II 24-hr 1-Year Rainfall=3.00"Conservancy Ph 2 BMP-2 SCS
Printed 4/25/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 7HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Hydrograph for Pond 2P: P1
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Outflow
(cfs)
Primary
(cfs)
Secondary
(cfs)
2.00 0.00 29,037 546.50 0.00 0.00 0.00
4.50 0.00 29,037 546.50 0.00 0.00 0.00
7.00 0.00 29,037 546.50 0.00 0.00 0.00
9.50 0.00 29,037 546.50 0.00 0.00 0.00
12.00 4.54 30,163 546.60 0.05 0.05 0.00
14.50 1.07 58,111 548.71 0.24 0.24 0.00
17.00 0.68 63,438 549.08 0.26 0.26 0.00
19.50 0.51 66,378 549.28 0.27 0.27 0.00
22.00 0.42 67,890 549.38 0.28 0.28 0.00
24.50 0.06 68,744 549.44 0.28 0.28 0.00
27.00 0.00 66,279 549.27 0.27 0.27 0.00
29.50 0.00 63,855 549.11 0.27 0.27 0.00
32.00 0.00 61,504 548.95 0.26 0.26 0.00
34.50 0.00 59,229 548.79 0.25 0.25 0.00
37.00 0.00 57,030 548.64 0.24 0.24 0.00
39.50 0.00 54,909 548.49 0.23 0.23 0.00
42.00 0.00 52,864 548.34 0.22 0.22 0.00
44.50 0.00 50,896 548.21 0.21 0.21 0.00
47.00 0.00 49,005 548.07 0.21 0.21 0.00
49.50 0.00 47,192 547.94 0.20 0.20 0.00
Type II 24-hr 1-Year Rainfall=3.00"Conservancy Ph 2 BMP-1 SCS
Printed 4/26/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 1HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Summary for Pond 2P: P1
Inflow Area = 17.260 ac, 13.15% Impervious, Inflow Depth = 0.51" for 1-Year event
Inflow = 7.49 cfs @ 12.16 hrs, Volume= 0.728 af
Outflow = 0.27 cfs @ 23.62 hrs, Volume= 0.714 af, Atten= 96%, Lag= 687.6 min
Primary = 0.27 cfs @ 23.62 hrs, Volume= 0.714 af
Secondary = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 5.00-120.00 hrs, dt= 0.05 hrs / 3
Starting Elev= 522.00' Surf.Area= 15,498 sf Storage= 45,790 cf
Peak Elev= 523.42' @ 23.62 hrs Surf.Area= 19,652 sf Storage= 71,233 cf (25,443 cf above start)
Plug-Flow detention time= (not calculated: initial storage exceeds outflow)
Center-of-Mass det. time= 2,171.5 min ( 3,083.6 - 912.0 )
Volume Invert Avail.Storage Storage Description
#1 518.00' 172,455 cf Custom Stage Data (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet)(sq-ft) (cubic-feet) (cubic-feet)
518.00 8,311 0 0
520.00 11,304 19,615 19,615
521.50 13,822 18,845 38,460
522.00 15,498 7,330 45,790
522.50 17,358 8,214 54,004
523.00 18,305 8,916 62,919
524.00 21,531 19,918 82,837
528.00 23,278 89,618 172,455
Device Routing Invert Outlet Devices
#1 Primary 520.00'18.0" Round Culvert L= 40.0' Ke= 0.500
Inlet / Outlet Invert= 520.00' / 519.75' S= 0.0063 '/' Cc= 0.900
n= 0.012, Flow Area= 1.77 sf
#2 Device 1 522.00'2.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Secondary 524.00'20.0' long x 8.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00 3.50 4.00 4.50 5.00 5.50
Coef. (English) 2.43 2.54 2.70 2.69 2.68 2.68 2.66 2.64 2.64
2.64 2.65 2.65 2.66 2.66 2.68 2.70 2.74
#4 Device 1 523.40'8.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
#5 Device 1 523.90'16.0' long x 1.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00
Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31
3.30 3.31 3.32
Type II 24-hr 1-Year Rainfall=3.00"Conservancy Ph 2 BMP-2 SCS
Printed 4/25/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 1HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Summary for Subcatchment 1S: Post-Dev
Runoff =12.07 cfs @ 12.19 hrs, Volume=1.179 af, Depth=0.63"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 2.00-50.00 hrs, dt= 0.05 hrs
Type II 24-hr 1-Year Rainfall=3.00"
Area (ac)CN Description
*0.793 98 Off-site undeveloped (future 25% impervious)
*2.381 61 Off-site undeveloped (future 75% lawn)
*0.482 98 Off-site Ph 1 area - impervious
*2.142 60 Off-site Ph 1 area - lawn (2-5%)
*0.918 55 Off-site Ph 1 area - undisturbed (wooded)
*4.462 55 On-site undisturbed (wooded)
*1.446 98 On-site - roadway
*2.900 98 On-site - buildings & drives
*0.703 60 On-site pond area
*2.541 60 On-site - lawns (heavy soils) (2-5% slopes)
*3.812 60 On-site - lawns (heavy soil (5-7% slopes)
22.580 68 Weighted Average
17.554 77.74% Pervious Area
5.026 22.26% Impervious Area
Tc Length Slope Velocity Capacity Description
(min)(feet)(ft/ft)(ft/sec)(cfs)
17.8 100 0.0279 0.09 Sheet Flow,
n= 0.400 P2= 3.56"
1.1 305 0.0827 4.63 Shallow Concentrated Flow,
Unpaved Kv= 16.1 fps
1.1 477 0.0610 7.12 14.25 Channel Flow,
Area= 2.0 sf Perim= 4.5' r= 0.44' n= 0.030
0.2 80 0.0100 7.80 24.51 Pipe Channel,
24.0" Round Area= 3.1 sf Perim= 6.3' r= 0.50'
n= 0.012
1.3 576 0.0590 7.34 22.01 Channel Flow,
Area= 3.0 sf Perim= 6.3' r= 0.48' n= 0.030
0.1 88 0.0350 19.12 135.18 Pipe Channel,
36.0" Round Area= 7.1 sf Perim= 9.4' r= 0.75'
n= 0.012
0.7 90 0.0190 2.22 Shallow Concentrated Flow,
Unpaved Kv= 16.1 fps
22.3 1,716 Total
Type II 24-hr 1-Year Rainfall=3.00"Conservancy Ph 2 BMP-2 SCS
Printed 4/25/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 2HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Hydrograph for Subcatchment 1S: Post-Dev
Time
(hours)
Precip.
(inches)
Excess
(inches)
Runoff
(cfs)
2.00 0.07 0.00 0.00
3.00 0.10 0.00 0.00
4.00 0.14 0.00 0.00
5.00 0.19 0.00 0.00
6.00 0.24 0.00 0.00
7.00 0.30 0.00 0.00
8.00 0.36 0.00 0.00
9.00 0.44 0.00 0.00
10.00 0.54 0.00 0.00
11.00 0.71 0.00 0.00
12.00 1.99 0.19 4.54
13.00 2.32 0.31 2.22
14.00 2.46 0.37 1.26
15.00 2.56 0.41 0.98
16.00 2.64 0.45 0.79
17.00 2.71 0.48 0.68
18.00 2.76 0.51 0.61
19.00 2.81 0.53 0.54
20.00 2.86 0.55 0.47
21.00 2.89 0.57 0.43
22.00 2.93 0.59 0.42
23.00 2.97 0.61 0.41
24.00 3.00 0.63 0.39
25.00 3.00 0.63 0.00
26.00 3.00 0.63 0.00
27.00 3.00 0.63 0.00
28.00 3.00 0.63 0.00
29.00 3.00 0.63 0.00
30.00 3.00 0.63 0.00
31.00 3.00 0.63 0.00
32.00 3.00 0.63 0.00
33.00 3.00 0.63 0.00
34.00 3.00 0.63 0.00
35.00 3.00 0.63 0.00
36.00 3.00 0.63 0.00
37.00 3.00 0.63 0.00
38.00 3.00 0.63 0.00
39.00 3.00 0.63 0.00
40.00 3.00 0.63 0.00
41.00 3.00 0.63 0.00
42.00 3.00 0.63 0.00
43.00 3.00 0.63 0.00
44.00 3.00 0.63 0.00
45.00 3.00 0.63 0.00
46.00 3.00 0.63 0.00
47.00 3.00 0.63 0.00
Time
(hours)
Precip.
(inches)
Excess
(inches)
Runoff
(cfs)
48.00 3.00 0.63 0.00
49.00 3.00 0.63 0.00
50.00 3.00 0.63 0.00
Type II 24-hr 1-Year Rainfall=3.00"Conservancy Ph 2 BMP-2 SCS
Printed 4/25/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 3HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Summary for Subcatchment 3S: Pre-Dev
Runoff =1.11 cfs @ 12.54 hrs, Volume=0.367 af, Depth=0.19"
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 2.00-50.00 hrs, dt= 0.05 hrs
Type II 24-hr 1-Year Rainfall=3.00"
Area (ac)CN Description
*22.580 55
22.580 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description
(min)(feet)(ft/ft)(ft/sec)(cfs)
34.5 Direct Entry,
Type II 24-hr 1-Year Rainfall=3.00"Conservancy Ph 2 BMP-2 SCS
Printed 4/25/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 4HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Hydrograph for Subcatchment 3S: Pre-Dev
Time
(hours)
Precip.
(inches)
Excess
(inches)
Runoff
(cfs)
2.00 0.07 0.00 0.00
3.00 0.10 0.00 0.00
4.00 0.14 0.00 0.00
5.00 0.19 0.00 0.00
6.00 0.24 0.00 0.00
7.00 0.30 0.00 0.00
8.00 0.36 0.00 0.00
9.00 0.44 0.00 0.00
10.00 0.54 0.00 0.00
11.00 0.71 0.00 0.00
12.00 1.99 0.01 0.02
13.00 2.32 0.05 0.84
14.00 2.46 0.08 0.54
15.00 2.56 0.09 0.42
16.00 2.64 0.11 0.36
17.00 2.71 0.12 0.32
18.00 2.76 0.14 0.29
19.00 2.81 0.15 0.27
20.00 2.86 0.16 0.23
21.00 2.89 0.17 0.21
22.00 2.93 0.18 0.21
23.00 2.97 0.19 0.21
24.00 3.00 0.19 0.20
25.00 3.00 0.19 0.01
26.00 3.00 0.19 0.00
27.00 3.00 0.19 0.00
28.00 3.00 0.19 0.00
29.00 3.00 0.19 0.00
30.00 3.00 0.19 0.00
31.00 3.00 0.19 0.00
32.00 3.00 0.19 0.00
33.00 3.00 0.19 0.00
34.00 3.00 0.19 0.00
35.00 3.00 0.19 0.00
36.00 3.00 0.19 0.00
37.00 3.00 0.19 0.00
38.00 3.00 0.19 0.00
39.00 3.00 0.19 0.00
40.00 3.00 0.19 0.00
41.00 3.00 0.19 0.00
42.00 3.00 0.19 0.00
43.00 3.00 0.19 0.00
44.00 3.00 0.19 0.00
45.00 3.00 0.19 0.00
46.00 3.00 0.19 0.00
47.00 3.00 0.19 0.00
Time
(hours)
Precip.
(inches)
Excess
(inches)
Runoff
(cfs)
48.00 3.00 0.19 0.00
49.00 3.00 0.19 0.00
50.00 3.00 0.19 0.00
Type II 24-hr 1-Year Rainfall=3.00"Conservancy Ph 2 BMP-2 SCS
Printed 4/25/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 5HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Summary for Pond 2P: P1
Inflow Area =22.580 ac,22.26% Impervious, Inflow Depth = 0.63" for 1-Year event
Inflow =12.07 cfs @ 12.19 hrs, Volume=1.179 af
Outflow =0.28 cfs @ 24.24 hrs, Volume=0.771 af, Atten= 98%, Lag= 723.0 min
Primary =0.28 cfs @ 24.24 hrs, Volume=0.771 af
Secondary =0.00 cfs @ 2.00 hrs, Volume=0.000 af
Routing by Stor-Ind method, Time Span= 2.00-50.00 hrs, dt= 0.05 hrs / 3
Starting Elev= 546.50' Surf.Area= 9,206 sf Storage= 29,037 cf
Peak Elev= 549.45' @ 24.24 hrs Surf.Area= 14,964 sf Storage= 68,866 cf (39,830 cf above start)
Plug-Flow detention time= 2,092.7 min calculated for 0.104 af (9% of inflow)
Center-of-Mass det. time= 916.6 min ( 1,817.7 - 901.2 )
Volume Invert Avail.Storage Storage Description
#1 542.00'112,234 cf Custom Stage Data (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet)(sq-ft)(cubic-feet)(cubic-feet)
542.00 4,488 0 0
546.00 7,893 24,762 24,762
546.50 9,206 4,275 29,037
547.00 12,770 5,494 34,531
548.00 14,115 13,443 47,973
549.00 14,265 14,190 62,163
550.00 15,834 15,050 77,213
551.00 17,445 16,640 93,852
552.00 19,319 18,382 112,234
Device Routing Invert Outlet Devices
#1 Primary 542.00'18.0" Round Culvert L= 48.0' Ke= 0.500
Inlet / Outlet Invert= 542.00' / 541.00' S= 0.0208 '/' Cc= 0.900
n= 0.012, Flow Area= 1.77 sf
#2 Device 1 546.50'2.5" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Secondary 551.00'20.0' long x 8.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00 3.50 4.00 4.50 5.00 5.50
Coef. (English) 2.43 2.54 2.70 2.69 2.68 2.68 2.66 2.64 2.64
2.64 2.65 2.65 2.66 2.66 2.68 2.70 2.74
#4 Device 1 549.80'8.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
#5 Device 1 550.30'16.0' long x 1.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00
Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31
Type II 24-hr 1-Year Rainfall=3.00"Conservancy Ph 2 BMP-2 SCS
Printed 4/25/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 6HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
3.30 3.31 3.32
Primary OutFlow Max=0.28 cfs @ 24.24 hrs HW=549.45' (Free Discharge)
1=Culvert (Passes 0.28 cfs of 22.02 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.28 cfs @ 8.26 fps)
4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 2.00 hrs HW=546.50' (Free Discharge)
3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Type II 24-hr 1-Year Rainfall=3.00"Conservancy Ph 2 BMP-2 SCS
Printed 4/25/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 7HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Hydrograph for Pond 2P: P1
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Outflow
(cfs)
Primary
(cfs)
Secondary
(cfs)
2.00 0.00 29,037 546.50 0.00 0.00 0.00
4.50 0.00 29,037 546.50 0.00 0.00 0.00
7.00 0.00 29,037 546.50 0.00 0.00 0.00
9.50 0.00 29,037 546.50 0.00 0.00 0.00
12.00 4.54 30,163 546.60 0.05 0.05 0.00
14.50 1.07 58,111 548.71 0.24 0.24 0.00
17.00 0.68 63,438 549.08 0.26 0.26 0.00
19.50 0.51 66,378 549.28 0.27 0.27 0.00
22.00 0.42 67,890 549.38 0.28 0.28 0.00
24.50 0.06 68,744 549.44 0.28 0.28 0.00
27.00 0.00 66,279 549.27 0.27 0.27 0.00
29.50 0.00 63,855 549.11 0.27 0.27 0.00
32.00 0.00 61,504 548.95 0.26 0.26 0.00
34.50 0.00 59,229 548.79 0.25 0.25 0.00
37.00 0.00 57,030 548.64 0.24 0.24 0.00
39.50 0.00 54,909 548.49 0.23 0.23 0.00
42.00 0.00 52,864 548.34 0.22 0.22 0.00
44.50 0.00 50,896 548.21 0.21 0.21 0.00
47.00 0.00 49,005 548.07 0.21 0.21 0.00
49.50 0.00 47,192 547.94 0.20 0.20 0.00
Type II 24-hr 1-Year Rainfall=3.00"Conservancy Ph 2 BMP-1 SCS
Printed 4/26/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 2HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Primary OutFlow Max=0.19 cfs @ 23.62 hrs HW=523.42' (Free Discharge)
1=Culvert (Passes 0.19 cfs of 13.90 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.13 cfs @ 5.73 fps)
4=Sharp-Crested Rectangular Weir (Weir Controls 0.06 cfs @ 0.43 fps)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 5.00 hrs HW=522.00' (Free Discharge)
3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Type II 24-hr 1-Year Rainfall=3.00"Conservancy Ph 2 BMP-1 SCS
Printed 4/26/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 3HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Hydrograph for Pond 2P: P1
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Outflow
(cfs)
Primary
(cfs)
Secondary
(cfs)
5.00 0.00 45,790 522.00 0.00 0.00 0.00
10.00 0.00 45,790 522.00 0.00 0.00 0.00
15.00 0.64 64,212 523.06 0.11 0.11 0.00
20.00 0.31 70,054 523.36 0.12 0.12 0.00
25.00 0.00 70,805 523.40 0.12 0.12 0.00
30.00 0.00 68,617 523.29 0.12 0.12 0.00
35.00 0.00 66,517 523.18 0.11 0.11 0.00
40.00 0.00 64,508 523.08 0.11 0.11 0.00
45.00 0.00 62,589 522.98 0.10 0.10 0.00
50.00 0.00 60,766 522.88 0.10 0.10 0.00
55.00 0.00 59,044 522.78 0.09 0.09 0.00
60.00 0.00 57,422 522.69 0.09 0.09 0.00
65.00 0.00 55,900 522.61 0.08 0.08 0.00
70.00 0.00 54,479 522.53 0.08 0.08 0.00
75.00 0.00 53,159 522.45 0.07 0.07 0.00
80.00 0.00 51,949 522.37 0.06 0.06 0.00
85.00 0.00 50,847 522.31 0.06 0.06 0.00
90.00 0.00 49,855 522.25 0.05 0.05 0.00
95.00 0.00 48,972 522.19 0.05 0.05 0.00
100.00 0.00 48,201 522.15 0.04 0.04 0.00
105.00 0.00 47,539 522.11 0.03 0.03 0.00
110.00 0.00 47,006 522.07 0.02 0.02 0.00
115.00 0.00 46,635 522.05 0.02 0.02 0.00
120.00 0.00 46,377 522.04 0.01 0.01 0.00

EXTENDED DETENTION

Waxhaw 2-yr Duration=19 min, Inten=3.52 in/hrConservancy Ph 2 BMP-1 Extended Det
Printed 4/28/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 1HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Summary for Pond 2P: P1
Inflow Area =17.260 ac,13.15% Impervious, Inflow Depth = 0.38" for 2-yr event
Inflow =20.66 cfs @ 0.32 hrs, Volume=0.546 af
Outflow =0.12 cfs @ 0.63 hrs, Volume=0.544 af, Atten= 99%, Lag= 19.0 min
Primary =0.12 cfs @ 0.63 hrs, Volume=0.544 af
Secondary =0.00 cfs @ 0.00 hrs, Volume=0.000 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.01 hrs / 3
Starting Elev= 522.00' Surf.Area= 15,498 sf Storage= 45,790 cf
Peak Elev= 523.32' @ 0.63 hrs Surf.Area= 19,353 sf Storage= 69,387 cf (23,597 cf above start)
Plug-Flow detention time= (not calculated: initial storage exceeds outflow)
Center-of-Mass det. time= 2,124.7 min ( 2,143.7 - 19.0 )
Volume Invert Avail.Storage Storage Description
#1 518.00'172,455 cf Custom Stage Data (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet)(sq-ft)(cubic-feet)(cubic-feet)
518.00 8,311 0 0
520.00 11,304 19,615 19,615
521.50 13,822 18,845 38,460
522.00 15,498 7,330 45,790
522.50 17,358 8,214 54,004
523.00 18,305 8,916 62,919
524.00 21,531 19,918 82,837
528.00 23,278 89,618 172,455
Device Routing Invert Outlet Devices
#1 Primary 520.00'18.0" Round Culvert L= 40.0' Ke= 0.500
Inlet / Outlet Invert= 520.00' / 519.75' S= 0.0063 '/' Cc= 0.900
n= 0.012, Flow Area= 1.77 sf
#2 Device 1 522.00'2.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Secondary 524.00'20.0' long x 8.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00 3.50 4.00 4.50 5.00 5.50
Coef. (English) 2.43 2.54 2.70 2.69 2.68 2.68 2.66 2.64 2.64
2.64 2.65 2.65 2.66 2.66 2.68 2.70 2.74
#4 Device 1 523.40'8.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
#5 Device 1 523.90'16.0' long x 1.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00
Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31
3.30 3.31 3.32
Waxhaw 2-yr Duration=19 min, Inten=3.52 in/hrConservancy Ph 2 BMP-1 Extended Det
Printed 4/28/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 2HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Primary OutFlow Max=0.12 cfs @ 0.63 hrs HW=523.32' (Free Discharge)
1=Culvert (Passes 0.12 cfs of 13.65 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.12 cfs @ 5.54 fps)
4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=522.00' (Free Discharge)
3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Waxhaw 2-yr Duration=19 min, Inten=3.52 in/hrConservancy Ph 2 BMP-1 Extended Det
Printed 4/28/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 3HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Hydrograph for Pond 2P: P1
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Outflow
(cfs)
Primary
(cfs)
Secondary
(cfs)
0.00 0.00 45,790 522.00 0.00 0.00 0.00
5.00 0.00 67,521 523.23 0.12 0.12 0.00
10.00 0.00 65,469 523.13 0.11 0.11 0.00
15.00 0.00 63,506 523.03 0.11 0.11 0.00
20.00 0.00 61,635 522.93 0.10 0.10 0.00
25.00 0.00 59,864 522.83 0.10 0.10 0.00
30.00 0.00 58,194 522.73 0.09 0.09 0.00
35.00 0.00 56,623 522.65 0.08 0.08 0.00
40.00 0.00 55,153 522.56 0.08 0.08 0.00
45.00 0.00 53,784 522.49 0.07 0.07 0.00
50.00 0.00 52,521 522.41 0.07 0.07 0.00
55.00 0.00 51,367 522.34 0.06 0.06 0.00
60.00 0.00 50,321 522.28 0.05 0.05 0.00
65.00 0.00 49,386 522.22 0.05 0.05 0.00
70.00 0.00 48,560 522.17 0.04 0.04 0.00
75.00 0.00 47,847 522.13 0.04 0.04 0.00
80.00 0.00 47,241 522.09 0.03 0.03 0.00
85.00 0.00 46,798 522.06 0.02 0.02 0.00
90.00 0.00 46,490 522.04 0.01 0.01 0.00
95.00 0.00 46,276 522.03 0.01 0.01 0.00
100.00 0.00 46,128 522.02 0.01 0.01 0.00
105.00 0.00 46,025 522.01 0.00 0.00 0.00
110.00 0.00 45,953 522.01 0.00 0.00 0.00
115.00 0.00 45,903 522.01 0.00 0.00 0.00
120.00 0.00 45,868 522.00 0.00 0.00 0.00
Waxhaw 25-yr Duration=19 min, Inten=5.13 in/hrConservancy Ph 2 BMP-1 Extended Det
Printed 4/28/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 4HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Summary for Pond 2P: P1
Inflow Area =17.260 ac,13.15% Impervious, Inflow Depth = 0.55" for 25-yr event
Inflow =30.09 cfs @ 0.32 hrs, Volume=0.795 af
Outflow =5.33 cfs @ 0.58 hrs, Volume=0.792 af, Atten= 82%, Lag= 15.6 min
Primary =5.33 cfs @ 0.58 hrs, Volume=0.792 af
Secondary =0.00 cfs @ 0.00 hrs, Volume=0.000 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.01 hrs / 3
Starting Elev= 522.00' Surf.Area= 15,498 sf Storage= 45,790 cf
Peak Elev= 523.74' @ 0.58 hrs Surf.Area= 20,694 sf Storage= 77,667 cf (31,878 cf above start)
Plug-Flow detention time= (not calculated: initial storage exceeds outflow)
Center-of-Mass det. time= 1,687.2 min ( 1,706.2 - 19.0 )
Volume Invert Avail.Storage Storage Description
#1 518.00'172,455 cf Custom Stage Data (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet)(sq-ft)(cubic-feet)(cubic-feet)
518.00 8,311 0 0
520.00 11,304 19,615 19,615
521.50 13,822 18,845 38,460
522.00 15,498 7,330 45,790
522.50 17,358 8,214 54,004
523.00 18,305 8,916 62,919
524.00 21,531 19,918 82,837
528.00 23,278 89,618 172,455
Device Routing Invert Outlet Devices
#1 Primary 520.00'18.0" Round Culvert L= 40.0' Ke= 0.500
Inlet / Outlet Invert= 520.00' / 519.75' S= 0.0063 '/' Cc= 0.900
n= 0.012, Flow Area= 1.77 sf
#2 Device 1 522.00'2.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Secondary 524.00'20.0' long x 8.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00 3.50 4.00 4.50 5.00 5.50
Coef. (English) 2.43 2.54 2.70 2.69 2.68 2.68 2.66 2.64 2.64
2.64 2.65 2.65 2.66 2.66 2.68 2.70 2.74
#4 Device 1 523.40'8.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
#5 Device 1 523.90'16.0' long x 1.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00
Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31
3.30 3.31 3.32
Waxhaw 25-yr Duration=19 min, Inten=5.13 in/hrConservancy Ph 2 BMP-1 Extended Det
Printed 4/28/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 5HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Primary OutFlow Max=5.29 cfs @ 0.58 hrs HW=523.74' (Free Discharge)
1=Culvert (Passes 5.29 cfs of 14.71 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.14 cfs @ 6.35 fps)
4=Sharp-Crested Rectangular Weir (Weir Controls 5.15 cfs @ 1.91 fps)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=522.00' (Free Discharge)
3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Waxhaw 25-yr Duration=19 min, Inten=5.13 in/hrConservancy Ph 2 BMP-1 Extended Det
Printed 4/28/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 6HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Hydrograph for Pond 2P: P1
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Outflow
(cfs)
Primary
(cfs)
Secondary
(cfs)
0.00 0.00 45,790 522.00 0.00 0.00 0.00
5.00 0.00 69,790 523.34 0.12 0.12 0.00
10.00 0.00 67,643 523.24 0.12 0.12 0.00
15.00 0.00 65,585 523.13 0.11 0.11 0.00
20.00 0.00 63,616 523.04 0.11 0.11 0.00
25.00 0.00 61,740 522.93 0.10 0.10 0.00
30.00 0.00 59,964 522.83 0.10 0.10 0.00
35.00 0.00 58,287 522.74 0.09 0.09 0.00
40.00 0.00 56,711 522.65 0.08 0.08 0.00
45.00 0.00 55,235 522.57 0.08 0.08 0.00
50.00 0.00 53,860 522.49 0.07 0.07 0.00
55.00 0.00 52,591 522.41 0.07 0.07 0.00
60.00 0.00 51,430 522.34 0.06 0.06 0.00
65.00 0.00 50,378 522.28 0.06 0.06 0.00
70.00 0.00 49,437 522.22 0.05 0.05 0.00
75.00 0.00 48,604 522.17 0.04 0.04 0.00
80.00 0.00 47,885 522.13 0.04 0.04 0.00
85.00 0.00 47,271 522.09 0.03 0.03 0.00
90.00 0.00 46,819 522.06 0.02 0.02 0.00
95.00 0.00 46,505 522.04 0.01 0.01 0.00
100.00 0.00 46,287 522.03 0.01 0.01 0.00
105.00 0.00 46,135 522.02 0.01 0.01 0.00
110.00 0.00 46,030 522.01 0.00 0.00 0.00
115.00 0.00 45,956 522.01 0.00 0.00 0.00
120.00 0.00 45,905 522.01 0.00 0.00 0.00
Waxhaw 50-yr Duration=19 min, Inten=5.51 in/hrConservancy Ph 2 BMP-1 Extended Det
Printed 4/28/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 7HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Summary for Pond 2P: P1
Inflow Area =17.260 ac,13.15% Impervious, Inflow Depth = 0.59" for 50-yr event
Inflow =32.31 cfs @ 0.32 hrs, Volume=0.853 af
Outflow =7.02 cfs @ 0.57 hrs, Volume=0.851 af, Atten= 78%, Lag= 14.9 min
Primary =7.02 cfs @ 0.57 hrs, Volume=0.851 af
Secondary =0.00 cfs @ 0.00 hrs, Volume=0.000 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.01 hrs / 3
Starting Elev= 522.00' Surf.Area= 15,498 sf Storage= 45,790 cf
Peak Elev= 523.81' @ 0.57 hrs Surf.Area= 20,926 sf Storage= 79,103 cf (33,314 cf above start)
Plug-Flow detention time= (not calculated: initial storage exceeds outflow)
Center-of-Mass det. time= 1,574.8 min ( 1,593.8 - 19.0 )
Volume Invert Avail.Storage Storage Description
#1 518.00'172,455 cf Custom Stage Data (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet)(sq-ft)(cubic-feet)(cubic-feet)
518.00 8,311 0 0
520.00 11,304 19,615 19,615
521.50 13,822 18,845 38,460
522.00 15,498 7,330 45,790
522.50 17,358 8,214 54,004
523.00 18,305 8,916 62,919
524.00 21,531 19,918 82,837
528.00 23,278 89,618 172,455
Device Routing Invert Outlet Devices
#1 Primary 520.00'18.0" Round Culvert L= 40.0' Ke= 0.500
Inlet / Outlet Invert= 520.00' / 519.75' S= 0.0063 '/' Cc= 0.900
n= 0.012, Flow Area= 1.77 sf
#2 Device 1 522.00'2.0" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Secondary 524.00'20.0' long x 8.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00 3.50 4.00 4.50 5.00 5.50
Coef. (English) 2.43 2.54 2.70 2.69 2.68 2.68 2.66 2.64 2.64
2.64 2.65 2.65 2.66 2.66 2.68 2.70 2.74
#4 Device 1 523.40'8.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
#5 Device 1 523.90'16.0' long x 1.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00
Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31
3.30 3.31 3.32
Waxhaw 50-yr Duration=19 min, Inten=5.51 in/hrConservancy Ph 2 BMP-1 Extended Det
Printed 4/28/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 8HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Primary OutFlow Max=7.00 cfs @ 0.57 hrs HW=523.81' (Free Discharge)
1=Culvert (Passes 7.00 cfs of 14.89 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.14 cfs @ 6.48 fps)
4=Sharp-Crested Rectangular Weir (Weir Controls 6.85 cfs @ 2.10 fps)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=522.00' (Free Discharge)
3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Waxhaw 50-yr Duration=19 min, Inten=5.51 in/hrConservancy Ph 2 BMP-1 Extended Det
Printed 4/28/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 9HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Hydrograph for Pond 2P: P1
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Outflow
(cfs)
Primary
(cfs)
Secondary
(cfs)
0.00 0.00 45,790 522.00 0.00 0.00 0.00
5.00 0.00 69,816 523.35 0.12 0.12 0.00
10.00 0.00 67,667 523.24 0.12 0.12 0.00
15.00 0.00 65,608 523.14 0.11 0.11 0.00
20.00 0.00 63,639 523.04 0.11 0.11 0.00
25.00 0.00 61,762 522.94 0.10 0.10 0.00
30.00 0.00 59,984 522.84 0.10 0.10 0.00
35.00 0.00 58,306 522.74 0.09 0.09 0.00
40.00 0.00 56,729 522.65 0.08 0.08 0.00
45.00 0.00 55,252 522.57 0.08 0.08 0.00
50.00 0.00 53,876 522.49 0.07 0.07 0.00
55.00 0.00 52,605 522.41 0.07 0.07 0.00
60.00 0.00 51,443 522.34 0.06 0.06 0.00
65.00 0.00 50,390 522.28 0.06 0.06 0.00
70.00 0.00 49,448 522.22 0.05 0.05 0.00
75.00 0.00 48,613 522.17 0.04 0.04 0.00
80.00 0.00 47,893 522.13 0.04 0.04 0.00
85.00 0.00 47,278 522.09 0.03 0.03 0.00
90.00 0.00 46,824 522.06 0.02 0.02 0.00
95.00 0.00 46,508 522.04 0.01 0.01 0.00
100.00 0.00 46,289 522.03 0.01 0.01 0.00
105.00 0.00 46,137 522.02 0.01 0.01 0.00
110.00 0.00 46,031 522.01 0.00 0.00 0.00
115.00 0.00 45,957 522.01 0.00 0.00 0.00
120.00 0.00 45,906 522.01 0.00 0.00 0.00
Waxhaw 2-yr Duration=22 min, Inten=3.26 in/hrConservancy Ph 2 BMP-2 Extended Det
Printed 4/26/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 1HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Summary for Pond 4P: P1
Inflow Area =22.580 ac,22.26% Impervious, Inflow Depth = 0.48" for 2-yr event
Inflow =29.31 cfs @ 0.37 hrs, Volume=0.895 af
Outflow =0.28 cfs @ 0.73 hrs, Volume=0.895 af, Atten= 99%, Lag= 21.9 min
Primary =0.28 cfs @ 0.73 hrs, Volume=0.895 af
Secondary =0.00 cfs @ 0.00 hrs, Volume=0.000 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.01 hrs / 3
Starting Elev= 546.50' Surf.Area= 9,206 sf Storage= 29,037 cf
Peak Elev= 549.36' @ 0.73 hrs Surf.Area= 14,827 sf Storage= 67,555 cf (38,519 cf above start)
Plug-Flow detention time= 2,982.0 min calculated for 0.229 af (26% of inflow)
Center-of-Mass det. time= 1,505.6 min ( 1,527.6 - 22.0 )
Volume Invert Avail.Storage Storage Description
#1 542.00'112,234 cf Custom Stage Data (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet)(sq-ft)(cubic-feet)(cubic-feet)
542.00 4,488 0 0
546.00 7,893 24,762 24,762
546.50 9,206 4,275 29,037
547.00 12,770 5,494 34,531
548.00 14,115 13,443 47,973
549.00 14,265 14,190 62,163
550.00 15,834 15,050 77,213
551.00 17,445 16,640 93,852
552.00 19,319 18,382 112,234
Device Routing Invert Outlet Devices
#1 Primary 542.00'18.0" Round Culvert L= 48.0' Ke= 0.500
Inlet / Outlet Invert= 542.00' / 541.00' S= 0.0208 '/' Cc= 0.900
n= 0.012, Flow Area= 1.77 sf
#2 Device 1 546.50'2.5" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Secondary 550.50'20.0' long x 8.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00 3.50 4.00 4.50 5.00 5.50
Coef. (English) 2.43 2.54 2.70 2.69 2.68 2.68 2.66 2.64 2.64
2.64 2.65 2.65 2.66 2.66 2.68 2.70 2.74
#4 Device 1 549.80'8.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
#5 Device 1 550.30'16.0' long x 1.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00
Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31
Waxhaw 2-yr Duration=22 min, Inten=3.26 in/hrConservancy Ph 2 BMP-2 Extended Det
Printed 4/26/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 2HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
3.30 3.31 3.32
Primary OutFlow Max=0.28 cfs @ 0.73 hrs HW=549.36' (Free Discharge)
1=Culvert (Passes 0.28 cfs of 21.87 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.28 cfs @ 8.14 fps)
4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=546.50' (Free Discharge)
3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Waxhaw 2-yr Duration=22 min, Inten=3.26 in/hrConservancy Ph 2 BMP-2 Extended Det
Printed 4/26/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 3HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Hydrograph for Pond 4P: P1
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Outflow
(cfs)
Primary
(cfs)
Secondary
(cfs)
0.00 0.00 29,037 546.50 0.00 0.00 0.00
5.00 0.00 63,400 549.08 0.26 0.26 0.00
10.00 0.00 58,802 548.76 0.25 0.25 0.00
15.00 0.00 54,511 548.46 0.23 0.23 0.00
20.00 0.00 50,528 548.18 0.21 0.21 0.00
25.00 0.00 46,854 547.92 0.20 0.20 0.00
30.00 0.00 43,500 547.67 0.18 0.18 0.00
35.00 0.00 40,471 547.44 0.16 0.16 0.00
40.00 0.00 37,767 547.24 0.14 0.14 0.00
45.00 0.00 35,387 547.06 0.12 0.12 0.00
50.00 0.00 33,346 546.89 0.10 0.10 0.00
55.00 0.00 31,698 546.74 0.08 0.08 0.00
60.00 0.00 30,452 546.63 0.06 0.06 0.00
65.00 0.00 29,653 546.56 0.03 0.03 0.00
70.00 0.00 29,300 546.52 0.01 0.01 0.00
75.00 0.00 29,149 546.51 0.01 0.01 0.00
80.00 0.00 29,085 546.50 0.00 0.00 0.00
85.00 0.00 29,057 546.50 0.00 0.00 0.00
90.00 0.00 29,046 546.50 0.00 0.00 0.00
95.00 0.00 29,041 546.50 0.00 0.00 0.00
100.00 0.00 29,038 546.50 0.00 0.00 0.00
105.00 0.00 29,037 546.50 0.00 0.00 0.00
110.00 0.00 29,037 546.50 0.00 0.00 0.00
115.00 0.00 29,037 546.50 0.00 0.00 0.00
120.00 0.00 29,037 546.50 0.00 0.00 0.00
Waxhaw 25-yr Duration=22 min, Inten=4.82 in/hrConservancy Ph 2 BMP-2 Extended Det
Printed 4/26/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 4HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Summary for Pond 4P: P1
Inflow Area =22.580 ac,22.26% Impervious, Inflow Depth = 0.70" for 25-yr event
Inflow =43.35 cfs @ 0.37 hrs, Volume=1.324 af
Outflow =8.93 cfs @ 0.66 hrs, Volume=1.324 af, Atten= 79%, Lag= 17.5 min
Primary =8.93 cfs @ 0.66 hrs, Volume=1.324 af
Secondary =0.00 cfs @ 0.00 hrs, Volume=0.000 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.01 hrs / 3
Starting Elev= 546.50' Surf.Area= 9,206 sf Storage= 29,037 cf
Peak Elev= 550.28' @ 0.66 hrs Surf.Area= 16,284 sf Storage= 81,865 cf (52,828 cf above start)
Plug-Flow detention time= 2,395.1 min calculated for 0.657 af (50% of inflow)
Center-of-Mass det. time= 1,358.4 min ( 1,380.4 - 22.0 )
Volume Invert Avail.Storage Storage Description
#1 542.00'112,234 cf Custom Stage Data (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet)(sq-ft)(cubic-feet)(cubic-feet)
542.00 4,488 0 0
546.00 7,893 24,762 24,762
546.50 9,206 4,275 29,037
547.00 12,770 5,494 34,531
548.00 14,115 13,443 47,973
549.00 14,265 14,190 62,163
550.00 15,834 15,050 77,213
551.00 17,445 16,640 93,852
552.00 19,319 18,382 112,234
Device Routing Invert Outlet Devices
#1 Primary 542.00'18.0" Round Culvert L= 48.0' Ke= 0.500
Inlet / Outlet Invert= 542.00' / 541.00' S= 0.0208 '/' Cc= 0.900
n= 0.012, Flow Area= 1.77 sf
#2 Device 1 546.50'2.5" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Secondary 550.50'20.0' long x 8.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00 3.50 4.00 4.50 5.00 5.50
Coef. (English) 2.43 2.54 2.70 2.69 2.68 2.68 2.66 2.64 2.64
2.64 2.65 2.65 2.66 2.66 2.68 2.70 2.74
#4 Device 1 549.80'8.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
#5 Device 1 550.30'16.0' long x 1.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00
Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31
Waxhaw 25-yr Duration=22 min, Inten=4.82 in/hrConservancy Ph 2 BMP-2 Extended Det
Printed 4/26/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 5HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
3.30 3.31 3.32
Primary OutFlow Max=8.90 cfs @ 0.66 hrs HW=550.28' (Free Discharge)
1=Culvert (Passes 8.90 cfs of 23.35 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.32 cfs @ 9.36 fps)
4=Sharp-Crested Rectangular Weir (Weir Controls 8.58 cfs @ 2.26 fps)
5=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=546.50' (Free Discharge)
3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Waxhaw 25-yr Duration=22 min, Inten=4.82 in/hrConservancy Ph 2 BMP-2 Extended Det
Printed 4/26/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 6HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Hydrograph for Pond 4P: P1
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Outflow
(cfs)
Primary
(cfs)
Secondary
(cfs)
0.00 0.00 29,037 546.50 0.00 0.00 0.00
5.00 0.00 70,893 549.58 0.29 0.29 0.00
10.00 0.00 65,853 549.25 0.27 0.27 0.00
15.00 0.00 61,104 548.93 0.26 0.26 0.00
20.00 0.00 56,656 548.61 0.24 0.24 0.00
25.00 0.00 52,517 548.32 0.22 0.22 0.00
30.00 0.00 48,685 548.05 0.20 0.20 0.00
35.00 0.00 45,166 547.79 0.19 0.19 0.00
40.00 0.00 41,972 547.55 0.17 0.17 0.00
45.00 0.00 39,102 547.34 0.15 0.15 0.00
50.00 0.00 36,558 547.15 0.13 0.13 0.00
55.00 0.00 34,338 546.98 0.11 0.11 0.00
60.00 0.00 32,487 546.81 0.09 0.09 0.00
65.00 0.00 31,034 546.68 0.07 0.07 0.00
70.00 0.00 29,986 546.59 0.04 0.04 0.00
75.00 0.00 29,443 546.54 0.02 0.02 0.00
80.00 0.00 29,210 546.52 0.01 0.01 0.00
85.00 0.00 29,111 546.51 0.00 0.00 0.00
90.00 0.00 29,068 546.50 0.00 0.00 0.00
95.00 0.00 29,050 546.50 0.00 0.00 0.00
100.00 0.00 29,043 546.50 0.00 0.00 0.00
105.00 0.00 29,039 546.50 0.00 0.00 0.00
110.00 0.00 29,038 546.50 0.00 0.00 0.00
115.00 0.00 29,037 546.50 0.00 0.00 0.00
120.00 0.00 29,037 546.50 0.00 0.00 0.00
Waxhaw 50-yr Duration=22 min, Inten=5.19 in/hrConservancy Ph 2 BMP-2 Extended Det
Printed 4/26/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 7HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Summary for Pond 4P: P1
Inflow Area =22.580 ac,22.26% Impervious, Inflow Depth = 0.76" for 50-yr event
Inflow =46.65 cfs @ 0.37 hrs, Volume=1.425 af
Outflow =13.15 cfs @ 0.63 hrs, Volume=1.425 af, Atten= 72%, Lag= 15.8 min
Primary =13.15 cfs @ 0.63 hrs, Volume=1.425 af
Secondary =0.00 cfs @ 0.00 hrs, Volume=0.000 af
Routing by Stor-Ind method, Time Span= 0.00-120.00 hrs, dt= 0.01 hrs / 3
Starting Elev= 546.50' Surf.Area= 9,206 sf Storage= 29,037 cf
Peak Elev= 550.39' @ 0.63 hrs Surf.Area= 16,459 sf Storage= 83,667 cf (54,630 cf above start)
Plug-Flow detention time= 2,207.1 min calculated for 0.758 af (53% of inflow)
Center-of-Mass det. time= 1,265.4 min ( 1,287.4 - 22.0 )
Volume Invert Avail.Storage Storage Description
#1 542.00'112,234 cf Custom Stage Data (Prismatic) Listed below
Elevation Surf.Area Inc.Store Cum.Store
(feet)(sq-ft)(cubic-feet)(cubic-feet)
542.00 4,488 0 0
546.00 7,893 24,762 24,762
546.50 9,206 4,275 29,037
547.00 12,770 5,494 34,531
548.00 14,115 13,443 47,973
549.00 14,265 14,190 62,163
550.00 15,834 15,050 77,213
551.00 17,445 16,640 93,852
552.00 19,319 18,382 112,234
Device Routing Invert Outlet Devices
#1 Primary 542.00'18.0" Round Culvert L= 48.0' Ke= 0.500
Inlet / Outlet Invert= 542.00' / 541.00' S= 0.0208 '/' Cc= 0.900
n= 0.012, Flow Area= 1.77 sf
#2 Device 1 546.50'2.5" Horiz. Orifice/Grate C= 0.600 Limited to weir flow at low heads
#3 Secondary 550.50'20.0' long x 8.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00 3.50 4.00 4.50 5.00 5.50
Coef. (English) 2.43 2.54 2.70 2.69 2.68 2.68 2.66 2.64 2.64
2.64 2.65 2.65 2.66 2.66 2.68 2.70 2.74
#4 Device 1 549.80'8.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s)
#5 Device 1 550.30'16.0' long x 1.0' breadth Broad-Crested Rectangular Weir
Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
2.50 3.00
Coef. (English) 2.69 2.72 2.75 2.85 2.98 3.08 3.20 3.28 3.31
Waxhaw 50-yr Duration=22 min, Inten=5.19 in/hrConservancy Ph 2 BMP-2 Extended Det
Printed 4/26/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 8HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
3.30 3.31 3.32
Primary OutFlow Max=13.06 cfs @ 0.63 hrs HW=550.39' (Free Discharge)
1=Culvert (Passes 13.06 cfs of 23.52 cfs potential flow)
2=Orifice/Grate (Orifice Controls 0.32 cfs @ 9.49 fps)
4=Sharp-Crested Rectangular Weir (Weir Controls 11.61 cfs @ 2.51 fps)
5=Broad-Crested Rectangular Weir (Weir Controls 1.12 cfs @ 0.80 fps)
Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=546.50' (Free Discharge)
3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Waxhaw 50-yr Duration=22 min, Inten=5.19 in/hrConservancy Ph 2 BMP-2 Extended Det
Printed 4/26/2020Prepared by HydroCAD SAMPLER 1-800-927-7246 www.hydrocad.net
Page 9HydroCAD® 10.10-3a Sampler s/n S09370 © 2020 HydroCAD Software Solutions LLC
This report was prepared with the free HydroCAD SAMPLER, which is licensed for evaluation and
educational use ONLY. For actual design or modeling applications you MUST use a full version of
HydroCAD which may be purchased at www.hydrocad.net. Full programs also include complete technical
support,training materials, and additional features which are essential for actual design work.
Hydrograph for Pond 4P: P1
Time
(hours)
Inflow
(cfs)
Storage
(cubic-feet)
Elevation
(feet)
Outflow
(cfs)
Primary
(cfs)
Secondary
(cfs)
0.00 0.00 29,037 546.50 0.00 0.00 0.00
5.00 0.00 70,930 549.58 0.29 0.29 0.00
10.00 0.00 65,888 549.25 0.27 0.27 0.00
15.00 0.00 61,136 548.93 0.26 0.26 0.00
20.00 0.00 56,687 548.61 0.24 0.24 0.00
25.00 0.00 52,545 548.32 0.22 0.22 0.00
30.00 0.00 48,711 548.05 0.20 0.20 0.00
35.00 0.00 45,190 547.79 0.19 0.19 0.00
40.00 0.00 41,993 547.56 0.17 0.17 0.00
45.00 0.00 39,122 547.34 0.15 0.15 0.00
50.00 0.00 36,575 547.15 0.13 0.13 0.00
55.00 0.00 34,353 546.98 0.11 0.11 0.00
60.00 0.00 32,499 546.82 0.09 0.09 0.00
65.00 0.00 31,043 546.68 0.07 0.07 0.00
70.00 0.00 29,992 546.59 0.05 0.05 0.00
75.00 0.00 29,445 546.54 0.02 0.02 0.00
80.00 0.00 29,211 546.52 0.01 0.01 0.00
85.00 0.00 29,111 546.51 0.00 0.00 0.00
90.00 0.00 29,069 546.50 0.00 0.00 0.00
95.00 0.00 29,050 546.50 0.00 0.00 0.00
100.00 0.00 29,043 546.50 0.00 0.00 0.00
105.00 0.00 29,039 546.50 0.00 0.00 0.00
110.00 0.00 29,038 546.50 0.00 0.00 0.00
115.00 0.00 29,037 546.50 0.00 0.00 0.00
120.00 0.00 29,037 546.50 0.00 0.00 0.00
D = 18"
Figure 8.06a  Design of outlet protection from a round pipe flowing full, minimum tailwater condition (Tw < 0.5 diameter)
Riprap Apron Design
BMP‐1 Outfall
Q10 = 4.4 cfs
La = 10'
d50 = 0.33'
REVISED 02-13-20
D = 18"
Figure 8.06a  Design of outlet protection from a round pipe flowing full, minimum tailwater condition (Tw < 0.5 diameter)
Riprap Apron Design
BMP‐2 Outfall
Q10 = 7.2 cfs
La = 10'
d50 = 0.33'
REVISED 02-13-20
RIPRAP APRON SUMMARY
Pipe No.Do
(in)
Q10
(cfs)
d50
(in)
La
(ft)
W1
(ft)
W2
(ft)
dmax
(in)
T
(in)
BMP-1 18 4.4 4 10 5 12 6 12
BMP-2 18 7.2 4 10 5 12 6 12
REVISED 02-13-20