8-25-14_FLO971523B_Hydrology&HydraulicsReport.pdf
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- Flo971523B 25-14
- Solicitation number
- 009-RFB-WRBWL_CY25-14
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- Dubuque County, Iowa
About this file
This Hydrology and Hydraulics Report, prepared by Bolton & Menk, Inc. for the Iowa Department of Agriculture & Land Stewardship (IDALS) Division of Soil Conservation and Water Quality, documents the design analysis for the Johnson Wetland Site nutrient reduction project in Floyd County, Iowa (IDALS ID No. FLO971523B). The report presents a comprehensive hydrologic and hydraulic study of a 766-acre (1.2 square mile) watershed draining to a proposed wetland with a normal pool area of 5.42 acres. Design parameters include rainfall events analyzed using the MSE 3 distribution for 5-, 10-, 25-, and 100-year storm events with depths of 3.80, 4.50, 5.60, and 7.50 inches respectively. The wetland design incorporates a primary spillway (sheet pile weir with a coefficient of 3.1) and secondary auxiliary spillway (grass waterway), with storage capacity of 5.29 acre-feet at normal pool elevation 1,171.00 and 39.91 acre-feet at the top of embankment. The site, located in NW 1/4 of Section 23, T-97N, R-15W, is designed for a 150-year accumulated sediment life with trap efficiency of 60 percent and sediment delivery ratio of 10 percent, resulting in approximately 1.22 acre-feet of submerged sediment accumulation and 0.23 acre-feet of aerated sediment. HydroCAD routing analysis confirms that the 10-year outflow passes only through the primary spillway while the 100-year storm utilizes both primary and secondary spillways with greater than one foot of freeboard maintained to the embankment crest.
The analysis demonstrates that the proposed wetland effectively attenuates peak flows across all design storms, with outflow reductions of 2 percent for the 5-year event (364.19 to 357.29 cfs) and approximately 1 percent for larger events. For the 100-year storm, the inflow of 917.63 cfs is reduced to 906.37 cfs outflow, with the secondary spillway activating to convey 47.96 cfs. The runoff curve number for the watershed is 85.0, based on hydrologic soil groups B and C consisting primarily of straight-row crops in good condition. Sediment calculations indicate average annual sheet and rill erosion of 22.2 tons per year delivered to the site, with total sediment delivery of 22.2 tons annually. Stage-storage relationships and duration-elevation tables provided in the report confirm the wetland's capacity to temporarily store and gradually release stormwater while maintaining the normal pool level at 1,171.00 feet for baseline conditions.
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IDALS ID No. FLO971523B
BMI Project No. 0T7130786
Site Location:
25-year Event: 5.60'' 100-year Event: 7.5''
* Hydrologic Soil Groups: B, C
* Runoff Curve Number: 85.0 (based on Land use shown in this report)
* Primary Spillway Weir Coefficent = 3.1
* Design life: 150 years for accumulated sediment
Tc = 4.0 hours determined by the sum of sheet, shallow concentrated and channel flow times.
Design Parameters and Procedures:
Hydrology Analysis Summary
Additional Site Analysis Data
The normal pool will contain 80% of the trapped sediment for the 150-year design life.
Sediment delivery is 10%, with a trap efficency of 60%.
Normal Pool area is 5.42 ac; surface watershed area is approx. 766 ac or 1.2 square miles
Hydrology and Hydraulics Report for the Johnson Wetland Site
Design hydrology and hydraulic study of this site was completed. The drainage area was determined and a stage-area-storage curve was developed based on the topographic survey, Lidar data available from the Iowa Department of Natural Resources, and grading design for the wetland. Land use and treatment were determined through a site visit and aerial photo review and depression areas were found. Hydrologic data was compiled, sediment calculations were made, the structure was flood routed using the SCS method in HydroCAD Software, and all the output was reviewed.
Rainfall events used for this site were MSE 3 distribution, 24-hour, 5-, 10-, 25-, and 100-year events. The primary spillway is a sheet pile weir. The secondary (auxiliary) spillway is a grass waterway. The pool and outlets are designed such that the 10-year outflow passes only through the primary spillway, and the 100-year storm passes through the primary and auxiliary spillways with greater than one foot of freeboard to the top of the embankment.
Floyd County, Iowa NW 1/4 of Section 23, T-97N, R-15W
Aerated sediment deposited will reduce flood storage by 0.23 acre-feet
H:\IDALS\0T7130786\3_Design\C_Reports\Johnson Hydrology Report.xlsm m BOLTON!/ & MENK Real People. Real Solutions.
Rainfall Data
IDALS ID Number: FLO971523B Job: Johnson
BMI Project Number: 0T7130786 Designed By: BCS Date: 05/16/2024
Reviewed By: P Date: 5/20/2L
Surface-Drained DA= 766 ac = 1.2 sq mi
The following rainfall data was used for the hydrology analysis of the site. Rainfall depths from three sources were compared, and the greatest depth was used to provide a conservative estimate of flood depths.
Frequency 24-hr yr in 1 in 3 in 4
2 3.06 3.06 3.10
5 3.82 3.83 3.80
10 4.52 4.55 4.50
25 5.56 5.67 5.60
50 6.45 6.63 6.50
100 7.40 7.68 7.50
References ,] Box indicates value used as required by NRCS design standards 1 NOAA Atlas 14, Volume 8, Version 2
SUDAS Design 2022 Edition 24-hour rainfall depths by county from NEH Title 210 (Figure IA2-25)
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Tributary Watershed Data
IDALS ID Number: FLO971523B Job: Johnson
BMI Project Number: 0T7130786 Designed By: BCS Date: 05/16/2024
Reviewed By: PR Date: 5/0/2024
Watershed Area (ac) Area (sq. mi.) Tile/Surface Drained
Main Watershed 766 1.20 Surface & Tile
Surface Total 766 1.20 (includes pothole trapped)1---------------~ Tile Total 766 1.20 (pumped and gravity).__ ____, H:\IDALS\0T7130786\3_Design\C_Reports\Johnson Hydrology Report.xlsm Page 3
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!) & MENK
Real People. Real Solutions.
IDALS ID Number: FLO971523B Job: Johnson
BMI Project Number: OT7130786 Designed By: BCS Date: 05/16/2024
Reviewed B.€ Date: 5/M/2f
Runoff Curve Number Surface-Drained DA= 766 ac = 1.2 sq mi
Soil Portion
Name' HSG' Cover Type and Hyd. Condition of W/S cN' Product percent
Tripoli Clay Loam, Readlyn Silt Loam, Maxfield Silt Loam, et al c/ Straight Row Crops, Good 95.0% 85 80.75
Basset Loam, et al B Straight Row Crops, Good 5.0% 78 3.9
References 'USDA - NRCS Soil Survey of Floyd County, Iowa.
2 USDA- NRCS Technical Release 55, Chapter 2, June 1986.
H:\IDALS\0T7130786\3_Design\C_Reports\Johnson Hydrology Report.xlsm
Total 100.0% 84.7
A BOLTON
'& MENK
Real People. Real Solutions.
Sediment Calculations
IDALS ID Number: FLO971523B Job: Johnson
BMI Project Number: 0T7130786 Designed By: BCS Date: 05/16/2024
Reviewed By. Se Date: 5/A/2f
Surface-Drained DA = 766 ac
= 1.2 sq mi
DA'
Trap efficiency, very short storage time Average annual sheet and rill erosion Area of depressions not subject to sediment delivery Area subject to sheet and rill erosion Average annual sheet and rill erosion Delivery ratio" Sheet and rill erosion delivered to site Adjustment for LRA 103° Adjusted sheet and rill erosion delivered Average annual gully erosion rate" Length of gully erosion In place density of gully material Average annual gully erosion (100% delivered) Total sediment delivered Weight of sediment retained in resevoir at Sediment accumulation during Estimate 80 Volume of submerged sediment at Normal pool volume Estimate 20 Volume of aerated sediment at
References
766 acres
60.0 percent trapped
1.197 1.0
10.0 74.1 0.3 22.2 0.2 0.0 22.2
2,000 1,600 1.22
0.23 sqmi percent tons/ac/yr acres acres tons percent tons/yr factor tons/yr cuft/ft ft lb/cuft t/yr t/yr t/yr tons tons acft tons acft
150 -year period percent of delivered sediment will not be submerged
1,307 Uact
5.3 acft, will not be full percent of delivered sediment will be aerated 1,742 tUacf?
' Determined by Engineer 2 USDA-NRCS, Engr. Field Man., Chap. 11, Amend. IA 27, Fig.2, May 1986,. Adjusted. See notes.
3 Estimated by preparer.
4 Estimated by preparer.
5 Delivery curve for Des Moines lobe. Source: Iowa Geological Survey.
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A BOLTON
U) & MENK
Real People. Real Solutions.
IDALS ID Number: FLO971523B Job: Johnson
BMI Project Number: OT7130786 Designed By: BCS Date: 05/16/2024
Reviewed By.R Date: 6/20/24
Stage-Storage Surface-Drained DA = 766 ac
= 1.2 sq mi
Volume Allow for Average Incremental Cumulativ Above Aerated Temporary
Contour Elev. Area Area Area Volume e Volume Weir Seditment Flood Storage
(sq ft) (Acres) (Arces) (Ac-ft) (Ac-ft) (Ac-ft) (Ac-ft) (Ac-ft)
1166.00 331 0.01 0.01 0.00 0.00
1167.00 711 0.02 0.01 0.01 0.01
1168.00 4142 0.10 0.06 0.06 0.07
1169.00 24171 0.55 0.32 0.32 0.39
1170.00 83379 1.91 1.23 1.23 1.63
1171.00 236030 5.42 3.67 3.67 5.29 0.00 0.00 0.00
1172.00 245478 5.64 5.53 5.53 10.82 5.53 0.23 5.30
1173.00 291555 6.69 6.16 6.16 16.98 11.69 0.23 11.46
1174.00 357974 8.22 7.46 7.46 24.44 19.15 0.23 18.92
1175.00 477389 10.96 9.59 9.59 34.03 28.74 0.23 28.51
1175.50 546969 12.56 11.76 5.88 39.91 34.61 0.23 34.38
Storage at Normal Pool 5.29 Acre-feet Elevation of weir= 1171.00
Average Depth= storage at normal pool area at normal pool
Storage at top of Dike 39.91 Acre-feet Elevation = 1175.50 Average Depth= 0.98 feet
Notes:
Storage areas include final earthwork borrow in pool area. Contour data is compiled from LiDAR, topographic survey, and proposed grading.
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Weir Flow Hydraulics
IDALS ID Number: FLO971523B Job: Johnson
BMI Project Number: OT7130786 Date: 05/16/2024 pate: 5/2»/2£
DA= 766 ac
= 1.2 sq mi
Designed By: BCS Reviewed y. /@
Input Q=CLH' Use C = 3.1
100-year inflow = 918 cfs Output
Pool El.= 1171.00 Weir Length (ft) 40 45 50 55 60
W.S. Elev. Q- cfs Q-cfs Q-cfs Q- cfs Q- cfs
1171.00 0.0 0.0 0.0 0.0 0.0
1171.28 18.5 20.8 23.1 25.4 27.7
1171.56 52.3 58.9 65.4 71.9 78.5
1171.84 96.1 108.1 120.1 132.1 144.2
1172.13 148.0 166.5 185.0 203.4 221.9
1172.41 206.8 232.6 258.5 284.3 310.2
1172.69 271.8 305.8 339.8 373.8 407.7
1172.97 342.5 385.4 428.2 471.0 513.8
1173.25 418.5 470.8 523.1 575.4 627.8
1173.53 499.4 561.8 624.2 686.6 749.1
1173.81 584.9 658.0 731.1 804.2 877.3
1174.09 674.8 759.1 843.5 927.8 1012.1
1174.38 768.8 864.9 961.0 1057.1 1153.3
1174.66 866.9 975.3 1083.6 1192.0 1300.4
1174.94 968.8 1089.9 1211.1 1332.2 1453.3
1175.22 1074.5 1208.8 1343.1 1477.4 1611.7
MAX POOL 1175.50 1183.7 1331.7 1479.6 1627.6 1775.5
USED
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IDALS ID Number: FLO971523B Job: Johnson
BMI Project Number: 0T7130786 Designed By: BCS Date: 05/16/2024
Reviewed By: 5°/ Date: 5/20/24
Results Surface-Drained DA= 766 ac = 1.2 sq mi
The following are based on surface flows and storm response. Discharge includes tile flow and overland flow.
c 11700>3> d 1168 uI k
0.00 5.00
Pool Area (ac)
Duration-Elevation Graph tNorma] Pool aPool Area (ac) aDischarge (els)
10.00
15.00
Pool Area-Elevation-Discharge Graph Discharge (cfs)
1000 500
1174.50
1174.00
1173.50
C 1173.00 0:.=; ...3> 1172.50 ".
a I
1172.00
1171.50
1171.00 0 4
H:\IDALS\0T7130786\3_Design\C_Reports\ohnson Hydrology Report.xlsm
8 12 Duration (Hours)
16 20
D-Year
25-year
100-year
A BOLTON!/ & MENK
IDALS ID Number: FLO971523B Job: Johnson
BMI Project Number: 0T7130786 Designed By: BCS Date: 05/16/2024
Reviewed By. SP2 Date: S/a0ya9
Results Surface-Drained DA= 766 ac = 1.2 sq mi
The Elevation-Discharge table below shows tile and surface outflows from the wetland for various elevations.
The tile discharge is very small compared to the surface discharge at higher elevations.
Total Discharge (cfs)Elevation Pool Area (ac)
1166.00 0.01 0
1167.00 0.02 0
1168.00 0.10 0
1169.00 0.55 0
1170.00 1.91 0
1171.00 5.42 0
1172.00 5.64 166
1173.00 6.69 385
1174.00 8.22 759
1175.00 10.96 1090
1175.50 12.56 1332
The Duration-Elevation table below shows the duration that the pool is at each listed elevation during the design storms. This is based on surface inflows during the design storms listed. The design for the wetland is based on tile flows, but the entire watershed is analyzed, including surface flows, to show that the proposed wetland does not have adverse impacts on surrounding properties during rainfall events.
Duration-Elevation Table 5-year 10-year 25-year 100-year
Duration Elevation Duration Elevation Duration Elevation Duration Elevation
0 1172.77 0 1173.08 0 1173.52 0 1174.13
2 1172.54 2 1172.82 2 1173.21 2 1173.78
4 1172.09 4 1172.27 4 1172.55 4 1172.99
6 1171.73 6 1171.86 6 1172.04 6 1172.34
8 1171.53 8 1171.61 8 1171.75 8 1171.94
10 1171.40 10 1171.46 10 1171.56 10 1171.71
12 1171.30 12 1171.36 12 1171.43 12 1171.56
14 1171.19 14 1171.24 14 1171.30 14 1171.41
16 1171.12 16 1171.15 16 1171.20 16 1171.28
18 1171.07 18 1171.09 18 1171.12 18 1171.18
20 1171.03 20 1171.05 20 1171.06 20 1171.11
22 1171.01 22 1171.02 22 1171.03 22 1171.07
24 1171.00 24 1171.01 24 1171.01 24 1171.02
H:\IDALS\0T7130786\3_Design\C_Reports\)ohnson Hydrology Report.xlsm Page 9
1S
Johnson Watershed
2P
Johnson Wetland
Routing Diagram for 130786_Final_FutureConditions Prepared by Bolton & Menk, Inc, Printed 5/8/2024
HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Subcat Reach Pond Link
130786_Final_FutureConditions Printed 5/8/2024Prepared by Bolton & Menk, Inc
Page 2HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Rainfall Events Listing
Event# Event
Name
Storm Type Curve Mode Duration
(hours)
B/B Depth
(inches)
AMC
1 5-YR MSE 24-hr 3 Default 24.00 1 3.80 2
2 10-YR MSE 24-hr 3 Default 24.00 1 4.50 2
3 25-YR MSE 24-hr 3 Default 24.00 1 5.60 2
4 100-YR MSE 24-hr 3 Default 24.00 1 7.50 2
130786_Final_FutureConditions
Page 3HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Area Listing (all nodes)
Area
(acres)
CN Description
(subcatchment-numbers)
766.000 85 (1S)
766.000 85 TOTAL AREA
MSE 24-hr 3 5-YR Rainfall=3.80"130786_Final_FutureConditions
Page 4HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Time span=5.00-100.00 hrs, dt=0.05 hrs, 1901 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Runoff Area=766.000 ac 0.00% Impervious Runoff Depth=2.28"Subcatchment 1S: Johnson Watershed Flow Length=8,042' Tc=238.2 min CN=85 Runoff=364.19 cfs 145.533 af
Peak Elev=1,172.77' Storage=15.417 af Inflow=364.19 cfs 145.533 afPond 2P: Johnson Wetland Primary=357.29 cfs 145.533 af Secondary=0.00 cfs 0.000 af Tertiary=0.00 cfs 0.000 af Outflow=357.29 cfs 145.533 af
Total Runoff Area = 766.000 ac Runoff Volume = 145.533 af Average Runoff Depth = 2.28" 100.00% Pervious = 766.000 ac 0.00% Impervious = 0.000 ac
Page 5HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Summary for Subcatchment 1S: Johnson Watershed
Runoff = 364.19 cfs @ 15.10 hrs, Volume= 145.533 af, Depth= 2.28" Routed to Pond 2P : Johnson Wetland
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-100.00 hrs, dt= 0.05 hrs MSE 24-hr 3 5-YR Rainfall=3.80"
Area (ac) CN Description
* 766.000 85
766.000 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs)
9.6 42 0.0050 0.07 Sheet Flow, Cultivated: Residue>20% n= 0.170 P2= 3.06"
228.6 8,000 0.0042 0.58 Shallow Concentrated Flow, Cultivated Straight Rows Kv= 9.0 fps
238.2 8,042 Total
Subcatchment 1S: Johnson Watershed
Runoff
Hydrograph
Time (hours) 1009590858075706560555045403530252015105
F lo w
(c fs
MSE 24-hr 3
5-YR Rainfall=3.80"
Runoff Area=766.000 ac
Runoff Volume=145.533 af
Runoff Depth=2.28"
Flow Length=8,042'
Tc=238.2 min
CN=85
364.19 cfs
Page 6HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Summary for Pond 2P: Johnson Wetland
Inflow Area = 766.000 ac, 0.00% Impervious, Inflow Depth = 2.28" for 5-YR event Inflow = 364.19 cfs @ 15.10 hrs, Volume= 145.533 af Outflow = 357.29 cfs @ 15.38 hrs, Volume= 145.533 af, Atten= 2%, Lag= 17.1 min Primary = 357.29 cfs @ 15.38 hrs, Volume= 145.533 af Secondary = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af Tertiary = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 5.00-100.00 hrs, dt= 0.05 hrs Starting Elev= 1,171.00' Surf.Area= 5.400 ac Storage= 5.245 af Peak Elev= 1,172.77' @ 15.38 hrs Surf.Area= 6.448 ac Storage= 15.417 af (10.172 af above start)
Plug-Flow detention time= 58.3 min calculated for 140.288 af (96% of inflow) Center-of-Mass det. time= 27.5 min ( 1,038.7 - 1,011.2 )
Volume Invert Avail.Storage Storage Description
#1 1,166.00' 39.655 af Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store (feet) (acres) (acre-feet) (acre-feet)
1,166.00 0.010 0.000 0.000 1,167.00 0.020 0.015 0.015 1,168.00 0.060 0.040 0.055 1,169.00 0.550 0.305 0.360 1,170.00 1.910 1.230 1.590 1,171.00 5.400 3.655 5.245 1,172.00 5.640 5.520 10.765 1,173.00 6.690 6.165 16.930 1,174.00 8.220 7.455 24.385 1,175.00 10.960 9.590 33.975 1,175.50 11.760 5.680 39.655
Device Routing Invert Outlet Devices
#1 Primary 1,171.00' 45.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s) 5.5' Crest Height
#2 Secondary 1,173.25' 20.0' long + 3.0 '/' SideZ x 20.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
#3 Device 4 1,166.50' 15.0" Round RCP_Round 15" L= 20.0' RCP, groove end projecting, Ke= 0.200 Inlet / Outlet Invert= 1,166.50' / 1,166.50' S= 0.0000 '/' Cc= 0.900 n= 0.011, Flow Area= 1.23 sf
#4 Device 5 1,175.00' 4.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s) 10.0' Crest Height
#5 Tertiary 1,166.50' 15.0" Round RCP_Round 15" L= 20.0' RCP, groove end projecting, Ke= 0.200 Inlet / Outlet Invert= 1,166.50' / 1,166.00' S= 0.0250 '/' Cc= 0.900 n= 0.011, Flow Area= 1.23 sf
Page 7HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Primary OutFlow Max=357.16 cfs @ 15.38 hrs HW=1,172.77' (Free Discharge) 1=Sharp-Crested Rectangular Weir (Weir Controls 357.16 cfs @ 4.52 fps)
Secondary OutFlow Max=0.00 cfs @ 5.00 hrs HW=1,171.00' (Free Discharge) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Tertiary OutFlow Max=0.00 cfs @ 5.00 hrs HW=1,171.00' (Free Discharge) 5=RCP_Round 15" (Passes 0.00 cfs of 14.54 cfs potential flow)
4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs) 3=RCP_Round 15" ( Controls 0.00 cfs)
Pond 2P: Johnson Wetland
Inflow Outflow Primary Secondary Tertiary
Hydrograph
Time (hours) 1009590858075706560555045403530252015105
F
Inflow Area=766.000 ac
Peak Elev=1,172.77'
Storage=15.417 af
364.19 cfs
357.29 cfs357.29 cfs
0.00 cfs0.00 cfs
Page 8HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Pond 2P: Johnson Wetland
Total Primary Secondary Tertiary
Stage-Discharge
Discharge (cfs) 1,6001,4001,2001,0008006004002000
E le v a ti o n
(f e e t)
1,175
1,174
1,173
1,172
1,171
1,170
1,169
1,168
1,167
1,166
Sharp-Crested Rectangular Weir
Broad-Crested Rectangular Weir
RCP_Round 15" + RCP_Round 15"
Sharp-Crested Rectangular Weir
Pond 2P: Johnson Wetland
Surface Storage
Stage-Area-Storage
Storage (acre-feet) 35302520151050
Surface/Horizontal/Wetted Area (acres) 11109876543210
E le v a ti e t)
1,175
1,174
1,173
1,172
1,171
1,170
1,169
1,168
1,167
1,166
Starting Elevation
Custom Stage Data
MSE 24-hr 3 10-YR Rainfall=4.50"130786_Final_FutureConditions
Page 9HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Time span=5.00-100.00 hrs, dt=0.05 hrs, 1901 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Runoff Area=766.000 ac 0.00% Impervious Runoff Depth=2.91"Subcatchment 1S: Johnson Watershed Flow Length=8,042' Tc=238.2 min CN=85 Runoff=466.40 cfs 185.700 af
Peak Elev=1,173.08' Storage=17.478 af Inflow=466.40 cfs 185.700 afPond 2P: Johnson Wetland Primary=458.07 cfs 185.700 af Secondary=0.00 cfs 0.000 af Tertiary=0.00 cfs 0.000 af Outflow=458.07 cfs 185.700 af
Total Runoff Area = 766.000 ac Runoff Volume = 185.700 af Average Runoff Depth = 2.91"
Page 10HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Summary for Subcatchment 1S: Johnson Watershed
Runoff = 466.40 cfs @ 15.09 hrs, Volume= 185.700 af, Depth= 2.91" Routed to Pond 2P : Johnson Wetland
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-100.00 hrs, dt= 0.05 hrs MSE 24-hr 3 10-YR Rainfall=4.50"
Area (ac) CN Description
* 766.000 85
766.000 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs)
9.6 42 0.0050 0.07 Sheet Flow, Cultivated: Residue>20% n= 0.170 P2= 3.06"
228.6 8,000 0.0042 0.58 Shallow Concentrated Flow, Cultivated Straight Rows Kv= 9.0 fps
238.2 8,042 Total
Subcatchment 1S: Johnson Watershed
Runoff
Hydrograph
Time (hours) 1009590858075706560555045403530252015105
F
MSE 24-hr 3
10-YR Rainfall=4.50"
Runoff Area=766.000 ac
Runoff Volume=185.700 af
Runoff Depth=2.91"
Flow Length=8,042'
Tc=238.2 min
466.40 cfs
Page 11HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Summary for Pond 2P: Johnson Wetland
Inflow Area = 766.000 ac, 0.00% Impervious, Inflow Depth = 2.91" for 10-YR event Inflow = 466.40 cfs @ 15.09 hrs, Volume= 185.700 af Outflow = 458.07 cfs @ 15.34 hrs, Volume= 185.700 af, Atten= 2%, Lag= 15.0 min Primary = 458.07 cfs @ 15.34 hrs, Volume= 185.700 af Secondary = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af Tertiary = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 5.00-100.00 hrs, dt= 0.05 hrs Starting Elev= 1,171.00' Surf.Area= 5.400 ac Storage= 5.245 af Peak Elev= 1,173.08' @ 15.34 hrs Surf.Area= 6.814 ac Storage= 17.478 af (12.233 af above start)
Plug-Flow detention time= 49.6 min calculated for 180.360 af (97% of inflow) Center-of-Mass det. time= 25.6 min ( 1,031.9 - 1,006.4 )
Volume Invert Avail.Storage Storage Description
#1 1,166.00' 39.655 af Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store (feet) (acres) (acre-feet) (acre-feet)
1,166.00 0.010 0.000 0.000 1,167.00 0.020 0.015 0.015 1,168.00 0.060 0.040 0.055 1,169.00 0.550 0.305 0.360 1,170.00 1.910 1.230 1.590 1,171.00 5.400 3.655 5.245 1,172.00 5.640 5.520 10.765 1,173.00 6.690 6.165 16.930 1,174.00 8.220 7.455 24.385 1,175.00 10.960 9.590 33.975 1,175.50 11.760 5.680 39.655
Device Routing Invert Outlet Devices
#1 Primary 1,171.00' 45.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s) 5.5' Crest Height
#2 Secondary 1,173.25' 20.0' long + 3.0 '/' SideZ x 20.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
#3 Device 4 1,166.50' 15.0" Round RCP_Round 15" L= 20.0' RCP, groove end projecting, Ke= 0.200 Inlet / Outlet Invert= 1,166.50' / 1,166.50' S= 0.0000 '/' Cc= 0.900 n= 0.011, Flow Area= 1.23 sf
#4 Device 5 1,175.00' 4.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s) 10.0' Crest Height
#5 Tertiary 1,166.50' 15.0" Round RCP_Round 15" L= 20.0' RCP, groove end projecting, Ke= 0.200
Page 12HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Primary OutFlow Max=457.94 cfs @ 15.34 hrs HW=1,173.08' (Free Discharge) 1=Sharp-Crested Rectangular Weir (Weir Controls 457.94 cfs @ 4.94 fps)
Secondary OutFlow Max=0.00 cfs @ 5.00 hrs HW=1,171.00' (Free Discharge) 2=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)
Tertiary OutFlow Max=0.00 cfs @ 5.00 hrs HW=1,171.00' (Free Discharge) 5=RCP_Round 15" (Passes 0.00 cfs of 14.54 cfs potential flow)
4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs) 3=RCP_Round 15" ( Controls 0.00 cfs)
Pond 2P: Johnson Wetland
Inflow Outflow Primary Secondary Tertiary
Hydrograph
Time (hours) 1009590858075706560555045403530252015105
F
Inflow Area=766.000 ac
Peak Elev=1,173.08'
Storage=17.478 af
466.40 cfs
458.07 cfs458.07 cfs
0.00 cfs0.00 cfs
Page 13HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Pond 2P: Johnson Wetland
Total Primary Secondary Tertiary
Stage-Discharge
Discharge (cfs) 1,6001,4001,2001,0008006004002000
E le v a ti e t)
1,175
1,174
1,173
1,172
1,171
1,170
1,169
1,168
1,167
1,166
Sharp-Crested Rectangular Weir
Broad-Crested Rectangular Weir
RCP_Round 15" + RCP_Round 15"
Sharp-Crested Rectangular Weir
Pond 2P: Johnson Wetland
Surface Storage
Stage-Area-Storage
Storage (acre-feet) 35302520151050
Surface/Horizontal/Wetted Area (acres) 11109876543210
E le v a ti e t)
1,175
1,174
1,173
1,172
1,171
1,170
1,169
1,168
1,167
1,166
MSE 24-hr 3 25-YR Rainfall=5.60"130786_Final_FutureConditions
Page 14HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Time span=5.00-100.00 hrs, dt=0.05 hrs, 1901 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Runoff Area=766.000 ac 0.00% Impervious Runoff Depth=3.93"Subcatchment 1S: Johnson Watershed Flow Length=8,042' Tc=238.2 min CN=85 Runoff=630.33 cfs 250.641 af
Peak Elev=1,173.52' Storage=20.587 af Inflow=630.33 cfs 250.641 afPond 2P: Johnson Wetland Primary=613.27 cfs 249.943 af Secondary=7.66 cfs 0.698 af Tertiary=0.00 cfs 0.000 af Outflow=620.93 cfs 250.641 af
Total Runoff Area = 766.000 ac Runoff Volume = 250.641 af Average Runoff Depth = 3.93"
Page 15HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Summary for Subcatchment 1S: Johnson Watershed
Runoff = 630.33 cfs @ 15.09 hrs, Volume= 250.641 af, Depth= 3.93" Routed to Pond 2P : Johnson Wetland
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-100.00 hrs, dt= 0.05 hrs MSE 24-hr 3 25-YR Rainfall=5.60"
Area (ac) CN Description
* 766.000 85
766.000 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs)
9.6 42 0.0050 0.07 Sheet Flow, Cultivated: Residue>20% n= 0.170 P2= 3.06"
228.6 8,000 0.0042 0.58 Shallow Concentrated Flow, Cultivated Straight Rows Kv= 9.0 fps
238.2 8,042 Total
Subcatchment 1S: Johnson Watershed
Runoff
Hydrograph
Time (hours) 1009590858075706560555045403530252015105
F
MSE 24-hr 3
25-YR Rainfall=5.60"
Runoff Area=766.000 ac
Runoff Volume=250.641 af
Runoff Depth=3.93"
Flow Length=8,042'
Tc=238.2 min
630.33 cfs
Page 16HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Summary for Pond 2P: Johnson Wetland
Inflow Area = 766.000 ac, 0.00% Impervious, Inflow Depth = 3.93" for 25-YR event Inflow = 630.33 cfs @ 15.09 hrs, Volume= 250.641 af Outflow = 620.93 cfs @ 15.28 hrs, Volume= 250.641 af, Atten= 1%, Lag= 11.6 min Primary = 613.27 cfs @ 15.28 hrs, Volume= 249.943 af Secondary = 7.66 cfs @ 15.28 hrs, Volume= 0.698 af Tertiary = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 5.00-100.00 hrs, dt= 0.05 hrs Starting Elev= 1,171.00' Surf.Area= 5.400 ac Storage= 5.245 af Peak Elev= 1,173.52' @ 15.28 hrs Surf.Area= 7.480 ac Storage= 20.587 af (15.342 af above start)
Plug-Flow detention time= 43.5 min calculated for 245.396 af (98% of inflow) Center-of-Mass det. time= 23.5 min ( 1,024.0 - 1,000.4 )
Volume Invert Avail.Storage Storage Description
#1 1,166.00' 39.655 af Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store (feet) (acres) (acre-feet) (acre-feet)
1,166.00 0.010 0.000 0.000 1,167.00 0.020 0.015 0.015 1,168.00 0.060 0.040 0.055 1,169.00 0.550 0.305 0.360 1,170.00 1.910 1.230 1.590 1,171.00 5.400 3.655 5.245 1,172.00 5.640 5.520 10.765 1,173.00 6.690 6.165 16.930 1,174.00 8.220 7.455 24.385 1,175.00 10.960 9.590 33.975 1,175.50 11.760 5.680 39.655
Device Routing Invert Outlet Devices
#1 Primary 1,171.00' 45.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s) 5.5' Crest Height
#2 Secondary 1,173.25' 20.0' long + 3.0 '/' SideZ x 20.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
#3 Device 4 1,166.50' 15.0" Round RCP_Round 15" L= 20.0' RCP, groove end projecting, Ke= 0.200 Inlet / Outlet Invert= 1,166.50' / 1,166.50' S= 0.0000 '/' Cc= 0.900 n= 0.011, Flow Area= 1.23 sf
#4 Device 5 1,175.00' 4.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s) 10.0' Crest Height
#5 Tertiary 1,166.50' 15.0" Round RCP_Round 15" L= 20.0' RCP, groove end projecting, Ke= 0.200
Page 17HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Primary OutFlow Max=613.17 cfs @ 15.28 hrs HW=1,173.52' (Free Discharge) 1=Sharp-Crested Rectangular Weir (Weir Controls 613.17 cfs @ 5.48 fps)
Secondary OutFlow Max=7.61 cfs @ 15.28 hrs HW=1,173.52' (Free Discharge) 2=Broad-Crested Rectangular Weir (Weir Controls 7.61 cfs @ 1.37 fps)
Tertiary OutFlow Max=0.00 cfs @ 5.00 hrs HW=1,171.00' (Free Discharge) 5=RCP_Round 15" (Passes 0.00 cfs of 14.54 cfs potential flow)
4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs) 3=RCP_Round 15" ( Controls 0.00 cfs)
Pond 2P: Johnson Wetland
Inflow Outflow Primary Secondary Tertiary
Hydrograph
Time (hours) 1009590858075706560555045403530252015105
F
Inflow Area=766.000 ac
Peak Elev=1,173.52'
Storage=20.587 af
630.33 cfs620.93 cfs613.27 cfs
7.66 cfs0.00 cfs
Page 18HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Pond 2P: Johnson Wetland
Total Primary Secondary Tertiary
Stage-Discharge
Discharge (cfs) 1,6001,4001,2001,0008006004002000
E le v a ti e t)
1,175
1,174
1,173
1,172
1,171
1,170
1,169
1,168
1,167
1,166
Sharp-Crested Rectangular Weir
Broad-Crested Rectangular Weir
RCP_Round 15" + RCP_Round 15"
Sharp-Crested Rectangular Weir
Pond 2P: Johnson Wetland
Surface Storage
Stage-Area-Storage
Storage (acre-feet) 35302520151050
Surface/Horizontal/Wetted Area (acres) 11109876543210
E le v a ti e t)
1,175
1,174
1,173
1,172
1,171
1,170
1,169
1,168
1,167
1,166
MSE 24-hr 3 100-YR Rainfall=7.50"130786_Final_FutureConditions
Page 19HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Time span=5.00-100.00 hrs, dt=0.05 hrs, 1901 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN
Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method
Runoff Area=766.000 ac 0.00% Impervious Runoff Depth=5.73"Subcatchment 1S: Johnson Watershed Flow Length=8,042' Tc=238.2 min CN=85 Runoff=917.63 cfs 365.880 af
Peak Elev=1,174.13' Storage=25.454 af Inflow=917.63 cfs 365.880 afPond 2P: Johnson Wetland Primary=858.41 cfs 358.515 af Secondary=47.96 cfs 7.365 af Tertiary=0.00 cfs 0.000 af Outflow=906.37 cfs 365.880 af
Total Runoff Area = 766.000 ac Runoff Volume = 365.880 af Average Runoff Depth = 5.73"
Page 20HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Summary for Subcatchment 1S: Johnson Watershed
Runoff = 917.63 cfs @ 15.08 hrs, Volume= 365.880 af, Depth= 5.73" Routed to Pond 2P : Johnson Wetland
Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-100.00 hrs, dt= 0.05 hrs MSE 24-hr 3 100-YR Rainfall=7.50"
Area (ac) CN Description
* 766.000 85
766.000 100.00% Pervious Area
Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs)
9.6 42 0.0050 0.07 Sheet Flow, Cultivated: Residue>20% n= 0.170 P2= 3.06"
228.6 8,000 0.0042 0.58 Shallow Concentrated Flow, Cultivated Straight Rows Kv= 9.0 fps
238.2 8,042 Total
Subcatchment 1S: Johnson Watershed
Runoff
Hydrograph
Time (hours) 1009590858075706560555045403530252015105
F
1,000
MSE 24-hr 3
100-YR Rainfall=7.50"
Runoff Area=766.000 ac
Runoff Volume=365.880 af
Runoff Depth=5.73"
Flow Length=8,042'
Tc=238.2 min
917.63 cfs
Page 21HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Summary for Pond 2P: Johnson Wetland
Inflow Area = 766.000 ac, 0.00% Impervious, Inflow Depth = 5.73" for 100-YR event Inflow = 917.63 cfs @ 15.08 hrs, Volume= 365.880 af Outflow = 906.37 cfs @ 15.23 hrs, Volume= 365.880 af, Atten= 1%, Lag= 8.8 min Primary = 858.41 cfs @ 15.23 hrs, Volume= 358.515 af Secondary = 47.96 cfs @ 15.23 hrs, Volume= 7.365 af Tertiary = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af
Routing by Stor-Ind method, Time Span= 5.00-100.00 hrs, dt= 0.05 hrs Starting Elev= 1,171.00' Surf.Area= 5.400 ac Storage= 5.245 af Peak Elev= 1,174.13' @ 15.23 hrs Surf.Area= 8.569 ac Storage= 25.454 af (20.209 af above start)
Plug-Flow detention time= 36.4 min calculated for 360.635 af (99% of inflow) Center-of-Mass det. time= 21.2 min ( 1,014.2 - 993.0 )
Volume Invert Avail.Storage Storage Description
#1 1,166.00' 39.655 af Custom Stage Data (Prismatic) Listed below (Recalc)
Elevation Surf.Area Inc.Store Cum.Store (feet) (acres) (acre-feet) (acre-feet)
1,166.00 0.010 0.000 0.000 1,167.00 0.020 0.015 0.015 1,168.00 0.060 0.040 0.055 1,169.00 0.550 0.305 0.360 1,170.00 1.910 1.230 1.590 1,171.00 5.400 3.655 5.245 1,172.00 5.640 5.520 10.765 1,173.00 6.690 6.165 16.930 1,174.00 8.220 7.455 24.385 1,175.00 10.960 9.590 33.975 1,175.50 11.760 5.680 39.655
Device Routing Invert Outlet Devices
#1 Primary 1,171.00' 45.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s) 5.5' Crest Height
#2 Secondary 1,173.25' 20.0' long + 3.0 '/' SideZ x 20.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Coef. (English) 2.68 2.70 2.70 2.64 2.63 2.64 2.64 2.63
#3 Device 4 1,166.50' 15.0" Round RCP_Round 15" L= 20.0' RCP, groove end projecting, Ke= 0.200 Inlet / Outlet Invert= 1,166.50' / 1,166.50' S= 0.0000 '/' Cc= 0.900 n= 0.011, Flow Area= 1.23 sf
#4 Device 5 1,175.00' 4.0' long Sharp-Crested Rectangular Weir 2 End Contraction(s) 10.0' Crest Height
#5 Tertiary 1,166.50' 15.0" Round RCP_Round 15" L= 20.0' RCP, groove end projecting, Ke= 0.200
Page 22HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Primary OutFlow Max=858.23 cfs @ 15.23 hrs HW=1,174.13' (Free Discharge) 1=Sharp-Crested Rectangular Weir (Weir Controls 858.23 cfs @ 6.18 fps)
Secondary OutFlow Max=47.87 cfs @ 15.23 hrs HW=1,174.13' (Free Discharge) 2=Broad-Crested Rectangular Weir (Weir Controls 47.87 cfs @ 2.41 fps)
Tertiary OutFlow Max=0.00 cfs @ 5.00 hrs HW=1,171.00' (Free Discharge) 5=RCP_Round 15" (Passes 0.00 cfs of 14.54 cfs potential flow)
4=Sharp-Crested Rectangular Weir ( Controls 0.00 cfs) 3=RCP_Round 15" ( Controls 0.00 cfs)
Pond 2P: Johnson Wetland
Inflow Outflow Primary Secondary Tertiary
Hydrograph
Time (hours) 1009590858075706560555045403530252015105
F
1,000
Inflow Area=766.000 ac
Peak Elev=1,174.13'
Storage=25.454 af
917.63 cfs906.37 cfs
858.41 cfs
47.96 cfs
0.00 cfs
Page 23HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Pond 2P: Johnson Wetland
Total Primary Secondary Tertiary
Stage-Discharge
Discharge (cfs) 1,6001,4001,2001,0008006004002000
E le v a ti e t)
1,175
1,174
1,173
1,172
1,171
1,170
1,169
1,168
1,167
1,166
Sharp-Crested Rectangular Weir
Broad-Crested Rectangular Weir
RCP_Round 15" + RCP_Round 15"
Sharp-Crested Rectangular Weir
Pond 2P: Johnson Wetland
Surface Storage
Stage-Area-Storage
Storage (acre-feet) 35302520151050
Surface/Horizontal/Wetted Area (acres) 11109876543210
E le v a ti e t)
1,175
1,174
1,173
1,172
1,171
1,170
1,169
1,168
1,167
1,166
Multi-Event Tables130786_Final_FutureConditions
Page 24HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Events for Subcatchment 1S: Johnson Watershed
Event Rainfall
(inches)
Runoff
(cfs)
Volume
(acre-feet)
Depth
(inches)
5-YR 3.80 364.19 145.533 2.28
10-YR 4.50 466.40 185.700 2.91
25-YR 5.60 630.33 250.641 3.93
100-YR 7.50 917.63 365.880 5.73
Multi-Event Tables130786_Final_FutureConditions
Page 25HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
Events for Pond 2P: Johnson Wetland
Event Inflow
(cfs)
Outflow
(cfs)
Primary
(cfs)
Secondary
(cfs)
Tertiary
(cfs)
Elevation
(feet)
Storage
(acre-feet)
5-YR 364.19 357.29 357.29 0.00 0.00 1,172.77 15.417
10-YR 466.40 458.07 458.07 0.00 0.00 1,173.08 17.478
25-YR 630.33 620.93 613.27 7.66 0.00 1,173.52 20.587
100-YR 917.63 906.37 858.41 47.96 0.00 1,174.13 25.454
Table of Contents130786_Final_FutureConditions
HydroCAD® 10.20-2d s/n 00709 © 2021 HydroCAD Software Solutions LLC
TABLE OF CONTENTS
Project Reports
1 Routing Diagram
2 Rainfall Events Listing
3 Area Listing (all nodes)
5-YR Event
4 Node Listing
5 Subcat 1S: Johnson Watershed
6 Pond 2P: Johnson Wetland
10-YR Event
9 Node Listing
10 Subcat 1S: Johnson Watershed
11 Pond 2P: Johnson Wetland
25-YR Event
14 Node Listing
15 Subcat 1S: Johnson Watershed
16 Pond 2P: Johnson Wetland
100-YR Event
19 Node Listing
20 Subcat 1S: Johnson Watershed
21 Pond 2P: Johnson Wetland
Multi-Event Tables
24 Subcat 1S: Johnson Watershed
25 Pond 2P: Johnson Wetland
File details come from the government source that posted it. Updated .