26-06-CER962218C_H&H Report.pdf

H:\IDALS\0T7133265\3_Design\C_Reports\Boehnke Design Report.docx

April 9, 2025

RE: Boehnke Wetland Design Report Site No. CER962218C Cerro Gordo County, Iowa

This wetland improvement is planned to provide nutrient reduction benefits to a part of the watershed of Cerro Gordo County DD #16. Nitrates will be converted to nitrogen gas through natural processes as the water passes through the wetland. Sediment with phosphorus will also be captured but will need to be removed occasionally.

The site is located within the properties of T & J Boehnke Farms, LLC and David & Melanie Boehnke just north of Ventura. It is bisected by the main and several laterals of Cerro Gordo Drainage District # 16.

Lateral 5 and the drainage district main will be re-laid and daylighted into the wetland with capacities exceeding the capacities of the existing tiles. Water will be diverted from Laterals 2 and 3 to the surface of the wetland via an inverted siphon. The siphon will be connected to the laterals at least 1.5 feet above the proposed wetland pool to provide driving head into the wetland. Laterals 2 and 3 will remain in service without decreased capacity. Lateral 4 will be re-laid around the wetland and will connect to the proposed wetland outlet pipe. The new pipe will have capacity sufficient to provide a ½” drainage coefficient. It will not daylight into the wetland because it could carry water polluted by lead ammunition from the adjacent shooting range.

The wetland pool will be excavated to allow tiles to be daylighted. Because of the long, narrow shape of the pool, diversion berms are not required.

The wetland outlet is a rectangular weir in an intake structure that conveys water back to the tile main through a 24” concrete pipe. The 24” pipe provides capacity sufficient for the re-laid laterals 4 and 5, the tile main, and the flows that will be diverted to the wetland from laterals 2 and 3. The proposed outlet pipe provides a ½” drainage coefficient for the main and laterals, and carries the full capture flow of laterals 2 and 3. The rectangular weir will fill the 18” pipe with a head less than 1’ so that no inlet pipe will be submerged during normal flows.

This site is a newer Tile Zone concept developed in cooperation with ISU and IDALS. Tile zone wetlands are designed within existing potholes to treat tile water for nitrate removal while not changing the basin’s response to surface runoff or storms. This is demonstrated empirically in the hydrology report (attached) and shown graphically/numerically on sheet A.03 of the plans. The storm bounces listed in the plans and hydrology report are based on modeling performed using Autodesk Storm and Sanitary Analysis. The existing and proposed conditions were both input into hydrology models and the outputs were compared. The proposed construction will not increase flooding for several reasons:

First, it does not change the surface runoff flow patterns. The wetland grading will not in any way change the direction or path of surface runoff because it will be underwater during any storm events.

Name: Boehnke Wetland Design Report Date: April 9, 2025 Page: 2

Second, excavating the wetland will decrease the flood elevation by setting the normal water elevation below the existing ground elevation and by providing increased storm detention.

Third, an outlet weir structure with a grated top will be provided as an outlet back to the tile main. During and after a storm event, this will maximize the rate at which water is able to leave the wetland. The limiting factor for how quickly the basin will return to its normal elevation after a rainfall event is the size of the existing tile.

Fourth, the re-laid laterals and the inverted siphon inlet will not have an adverse impact on the storm response of the wetland. The storm response is based on the surrounding land (determining the flow of water into the wetland), pothole topography, and available outlets.

This project will not change the surrounding land, and it will only positively impact the pothole topography as discussed above. The water that will be routed by this project to the surface of the wetland is water that would otherwise still have been conveyed through the existing drainage district tile main. The tile main is the only subsurface outlet for water leaving the wetland.

This wetland has six watershed basins contributing to surface and/or tile runoff. Five of the basins contribute to surface runoff, including Lateral 3, Lateral 4, Lateral 5, Main Upstream, and Direct watersheds. Surface Runoff from the Lateral 5 and Main Upstream watersheds passes through culverts which are included in the hydrology model. Lateral 2, Lateral 3, Lateral 5, and Main Upstream watersheds contribute tile runoff to the wetland as discussed above.

The NRCS Conservation Practice Standards (CPSs) used for this project are 656 (Constructed Wetland) and 587 (Structure for Water Control). CPS 656 was chosen because the purpose of this project is improving water quality and treating contaminated runoff. CPS 587 was chosen for the outlet structure because its purpose is to control the water level in the wetland and convey water to the tile. However, tile zone wetlands do not fit well within the framework of CPS 656 because they are not created by an embankment, and they do not change the storm response of the pothole. Since this wetland is an existing and historical pothole, since there is no constructed impoundment, and since the outlet is an existing tile main, it cannot be constructed to convey the 25-year storm. The 25-year storm will continue to fill the pothole and overflow to the east just as it does in its existing condition. For the same reasons, the wetland cannot be designed to meet the standards of CPS Pond (Code 378). CPS 587 states that “Inflow will be limited to the capacity originally apportioned to the drain.” This is met in the proposed design because all the water that flows to the wetland and into the outlet structure is water that would otherwise still have been directed to the existing tile main. Furthermore, in a drainage district the capacity apportioned to an area or a property is the capacity that is available in the drain. There are no limits placed on water that may be discharged to the main.

This project is NRCS Engineering Job Class IV because the constructed wetland is for field runoff treatment with a drainage area between 300 and 1000 acres. Under CPS 587, the project is Job Class IV because the drainage area is between 250 and 640 acres.

Bolton & Menk reviewed the soil survey data for the location and found primarily muck within the wetland area, and loam in the rest of the site. After this review, it was determined that soil borings were unnecessary.

Name:

Date:

Page:

Boehnke Wetland Design Report April 9, 2025

The hydrology of the watersheds contributing both directly and indirectly to the proposed wetland were analyzed. Most of the watershed is agricultural crop and pasture. A map of the contributing watersheds is included with this report. For conservancy of the design, all land was assumed as cultivated to develop an average CN for the project of 83.7 used in the hydrologic analysis. The watersheds were routed through the wetland in its existing and proposed conditions to determine the wetland performance. See the attached hydrology report and outputs from SSA for the results.

The permanent easement for this project will be on the Boehnke properties. IDALS-DSWQ is currently in the process of updating the abstracts and will have a signed easement recorded for the area as shown in the plans. No additional land rights are needed for the project.

The Section 401/404 permit application, floodplain permit application, and archaeological reconnaissance will be addressed by IDALS-DSWQ if required for this project.

Sincerely, Bolton & Menk, Inc.

Brandon C Short, PE Water Resources Project Engineer

Encl: Soil Survey Map Watershed Map Hydrology & Hydraulics Report Hydrology & Hydraulics Modeling Output

Botton & Menk is an equal opportunity employer.

Page: 4

Web Soil Survey Maps (Watershed and Site)

Page: 5

Lateral 5 160 Ac

Lateral 4 32 Ac

Lateral 2 60 Ac

Lateral 3 142 Ac

Direct 84 Ac

Main Upstream

60 Ac

Cerro Gordo Wetland IDALS Project No. CER962218C

Watershed Map May 2025

M ap

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W et la nd

.a pr x | D at e

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Legend !I

TC Flowpaths

Watershed Boundaries

Wetland Pool

Existing Tiles

Proposed Tiles

0 500 1,000 1,500250

Feet Source:

25-year Event: 5.70'' 100-year Event: 7.6''

* Hydrologic Soil Groups: A, B, C

* Runoff Curve Number: 83.7 (based on Land use shown in this report)

* Primary Spillway Weir Coefficent = 3.1

* Design life: 150 years for accumulated sediment

* Proposed construction lowers storm bounce elevations

Tc = 1.7 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 7%, with a trap efficency of 62%.

Normal Pool area is 6.3 ac; surface watershed area is approx. 478 ac or 0.75 square miles

Report Summary

This report summarizes the hydrology and hydraulic analysis completed for the Boehnke wetland site. 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 Autodesk Storm and Sanitary Analysis (SSA) 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 an outlet structure with a rectangular weir that discharges to the existing drain tile main. The secondary spillway is a the natural overflow of the existing pothole. Values shown below for Q Out include overland flow and tile flow.

Aerated sediment deposited will reduce flood storage by 0.24 acre-feet

H:\IDALS\0T7133265\3_Design\C_Reports\Cerro Gordo Hydrology Report.xlsm

IDALS ID Number: CER962218C Job: Boehnke

BMI Project Number: 0T7.133265 Designed By: BCS Date: 4/9/2025

Rainfall Data

Frequency yr in 1 in 2 in 3 in 4

2 3.02 2.75 3.06 3.10

5 3.80 3.50 3.83 3.80

10 4.56 4.14 4.55 4.60

25 5.76 5.11 5.67 5.70

50 6.82 5.97 6.63 6.60

100 7.99 6.92 7.68 7.60

References

1 NOAA Atlas 14, Volume 8, Version 2 2 Autodesk Storm and Sanitary Analysis Rainafall Designer 3 SUDAS Design 2025 Edition 4 24-hour rainfall depths by county from NEH Title 210 (Figure IA2-25)

Box indicates rainfall depth used for modeling.

The following rainfall data was used for the hydrology analysis of the site. Rainfall depths from four sources are shown, and the rainfall depths from the NEH Title 210 figure were used. MSE 3 was used for the rainfall distribution.

24-hr

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BMI Project Number: 0T7.133265 Designed By: BCS Date: 4/9/2025

Tributary Watershed Data

Watershed Area (ac) Area (sq. mi.) Tile/Surface Drained

Direct 84 0.13 Surface

Lateral 2 60 0.09 Tile

Lateral 3 142 0.22 Surface & Tile

Lateral 4 32 0.05 Surface

Lateral 5 160 0.25 Surface & Tile

Main Upstream 60 0.09 Surface & Tile

Surface Total 478 0.75

Tile Total 422 0.66

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BMI Project Number: 0T7.133265 Designed By: BCS Date: 4/9/2025

Soil Portion Name1 HSG1 Cover Type and Hyd. Condition of W/S CN2 Product percent

Houghton Muck, et al A, A/D Straight Row Crops, Good 3.4% 67 2.278

Clarion Loam, et al B Straight Row Crops, Good 10.2% 78 7.956

Clarion Loam, et al C, C/D Straight Row Crops, Good 86.4% 85 73.44

Total 100.0% 83.7

References 1 USDA - NRCS Soil Survey of Cerro Gordo Co., Iowa.

2 USDA - NRCS Technical Release 55, Chapter 2, June 1986.

Runoff Curve Number

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BMI Project Number: 0T7.133265 Designed By: BCS Date: 4/9/2025

Sediment Calculations

DA1

478 acres 0.747 sqmi

Trap efficiency, very short storage time2 62 percent

Average annual sheet and rill erosion3

2.6 tons/ac/yr

Area of depressions not subject to sediment delivery 82 acres

Area subject to sheet and rill erosion 396 acres

Average annual sheet and rill erosion 1,043 tons

Delivery ratio5

7.0 percent

Sheet and rill erosion delivered to site 73.0 tons/yr

Adjustment for LRA 1032

0.3 factor

Adjusted sheet and rill erosion delivered 21.9 tons/yr

Average annual gully erosion rate4

0.2 cuft/ft

Length of gully erosion 100 ft

In place density of gully material 80 lb/cuft

Average annual gully erosion (100% delivered) 0.8 t/yr

Total sediment delivered 22.7 t/yr

Weight of sediment retained in resevoir at 62.0 percent trapped2 14 t/yr

Sediment accumulation during 150 -year period 2,100 tons

Estimate 80 percent of delivered sediment will not be submerged2 1,680 tons

Volume of submerged sediment at 1,307 t/acft2 1.29 acft

Normal pool volume 6.2 acft, will not be full

Estimate 20 percent of delivered sediment will be aerated2 420 tons

Volume of aerated sediment at 1,742 t/acft2 0.24 acft

References 1 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.

Surface-Drained DA = 478 ac

= .75 sq mi

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BMI Project Number: 0T7.133265 Designed By: BCS Date: 4/9/2025

Stage-Storage

Contour Elev. Area Area Average

Area Incremental

Volume Cumulative

Volume

Volume Above Weir

Allow for Aerated

Seditment Temporary

Flood Storage

(sq ft) (Acres) (Arces) (Ac-ft) (Ac-ft) (Ac-ft) (Ac-ft) (Ac-ft)

1232.00 262400 6.02 6.02 0.00 0.00

1233.00 274400 6.30 6.16 6.16 6.16 0.00 0.00 0.00

1235.00 298900 6.86 6.58 13.16 19.32 13.16 0.24 12.92

1236.00 706200 16.21 11.54 11.54 30.86 24.70 0.24 24.46

1237.00 931200 21.38 18.79 18.79 49.65 43.49 0.24 43.25

1238.00 1142900 26.24 23.81 23.81 73.46 67.30 0.24 67.06

1239.00 1315000 30.19 28.21 28.21 101.67 95.51 0.24 95.27

1240.00 1448600 33.26 31.72 31.72 133.40 127.23 0.24 126.99

1241.00 1569700 36.04 34.65 34.65 168.04 161.88 0.24 161.64

1242.00 1665900 38.24 37.14 37.14 205.18 199.02 0.24 198.78

Storage at Normal Pool 6.16 Acre-feet storage at normal pool

Elevation of weir = 1233.00 area at normal pool

Storage at Overflow 73.46 Acre-feet

1238.00 0.98 feet

Notes:

Average Depth =

Average Depth =Elevation =

Storage areas include final earthwork in pool area. Contour data is compiled from LiDAR, topographic survey, and proposed grading.

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BMI Project Number: 0T7.133265 Designed By: BCS Date: 4/9/2025

Watershed Name Watershed Area (ac) QFC (cfs)1

% of Existing Tile capacity

% of 1/2" Dc

Average Tile Flow Rate

(cfs)2

Percent Captured of

Annual Flow3

Lateral 2 & 3 202 1.32 19.8% 31.1% 0.2 97.4% Lateral 54 160 3.54 unknown 105% 0.16 100%

Main4 60 2.5 132% 198% 0.06 100%

Notes:

1 QFC for partial capture inlet. Pipe capacity calculated with Manning's equation for full capture inlet 2 Average flow calculated from flow-duration data from the USGS StreamStats Application 3 Approximated using StreamStats to model tile flow 4 This is a full-capture re-laid tile

Full Capture Flow (QFC) is the tile flow rate that can be entirely captured by the partial flow gravity inlet system. If the tile flow is less than QFC, it will be entirely diverted to the wetland. When the tile flow is greater than QFC, a portion of the flow (slightly more than QFC) will be diverted to the wetland. QFC calculations were performed using the Hazen- Williams equation and take into account the head over the inlet weir.

Intercept Capacities

Gravity Inlet Calculations

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BMI Project Number: 0T7.133265 Designed By: BCS Date: 4/9/2025

268400

Watershed Area (ac) Percent Capture

Effective Capture Area (ac)

Average Flow Captured (cf/d)1

Full Flow Captured

(cf/d)2

Average Residence Time (d)3

Full Flow Residence Time (d)4

Lateral 2 & 3 202 97.4% 197 9733 114048 Lateral 5 160 100.0% 160 13824 305856

Main 60 100.0% 60 5184 216000 Wetland Total 422 98.8% 417 28741 635904 9.3 0.4

Notes:

3 Based on normal pool volume and average flow capture

Total Capture Calculations

Wetland Normal Pool Volume (cf)

1 average capture for gravity inlets, estimated from StreamStats 2 QFC or 1 csm for gravity inlets

4 Based on normal pool volume and full flow capture

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BMI Project Number: 0T7.133265 Designed By: BCS Date: 4/9/2025

Base Flow (cfs) 7.36 =Full Flow Calculated Above

Base Flow Weir Head (ft) 0.71

Average Flow (cfs) 0.33 =Average Flow Calculated Above

Average Flow Weir Head (ft) 0.09

Average Flow Pool Elevation 1233.09

Tributary Required Capacity Notes

Lateral 4 0.672 Assumed 1/2" DC Lateral 5 3.36 Assumed 1/2" DC Lateral 2 & 3 1.32 QFC

Total Required Capacity 5.35 Provided Capacity 7.15 24" RCP @ 0.1%

The head over the outlet weir will be 0.69 ft in order to fill the outlet pipe. This will not affect the function of the district tiles. Daylighted tiles will discharge 1 ft above the NWL.

Wetland Outlet Pipe Capacity

Wetland Outlet Weir Capacities

The following calculations show the performance of the outlet weir.

The following calculations show that the proposed wetland outlet pipe is sufficient to convey flows necessary to maintain drainage district facility capacities.

Note:

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BMI Project Number: 0T7.133265 Designed By: BCS Date: 4/9/2025

Results The following are based on surface flows and storm response. Discharge includes tile flow and overland flow.

01020304050

0.00 10.00 20.00 30.00 40.00 50.00

Discharge (cfs)

E le va ti o n

Pool Area (ac)

Pool Area-Elevation-Discharge Graph

Normal Pool

Pool Area (ac)

Discharge (cfs)

1237.50

1238.00

1238.50

1239.00

1239.50

1240.00

1240.50

1241.00

1241.50

0 4 8 12 16 20 24

E le va ti o n

Duration (Hours)

Duration-Elevation Graph

5-Year

10-Year

25-year

100-year

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BMI Project Number: 0T7.133265 Designed By: BCS Date: 4/9/2025

Results

1232.00 6.02 0 0 0

1233.00 6.30 0 0 0

1235.00 6.86 3.71 0 3.22

1236.00 16.21 4.42 0 3.71

1237.00 21.38 5.03 0 4.42

1238.00 26.24 5.45 0 5.03

1239.00 30.19 6 3.85 5.45

1240.00 33.26 6.5 35.5 9.85

1241.00 36.04

1242.00 38.24

5-year 10-year 25-year 100-year Duration Elevation Duration Elevation Duration Elevation Duration Elevation

0 1238.01 0 1238.96 0 1240.04 0 1241.20 2 1238.00 2 1238.96 2 1240.01 2 1241.20 4 1237.99 4 1238.95 4 1240.03 4 1241.16 6 1237.99 6 1238.95 6 1240.02 6 1241.12 8 1237.96 8 1238.93 8 1240.00 8 1241.06

10 1237.94 10 1238.92 10 1239.98 10 1240.99 12 1237.92 12 1238.91 12 1239.96 12 1240.91 14 1237.89 14 1238.88 14 1239.94 14 1240.82 16 1237.86 16 1238.85 16 1239.91 16 1240.74 18 1237.83 18 1238.82 18 1239.88 18 1240.66 20 1237.80 20 1238.79 20 1239.85 20 1240.59 22 1237.76 22 1238.76 22 1239.82 22 1240.52 24 1237.72 24 1238.73 24 1239.78 24 1240.45

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

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.

Elevation Pool Area

(ac) Tile Discharge

(cfs) Surface

Discharge (cfs) Total Discharge

(cfs)

= .75 sq mi Surface-Drained DA = 478 ac

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Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis

Project Description

133265 SSA Proposed.SPF

Project Options

CFS

Elevation

SCS TR-55

SCS TR-55

Hydrodynamic

NO

NO

Analysis Options

00:00:00 0:00:00

00:00:00 0:00:00

00:00:00 0:00:00

0 days

0 01:00:00 days hh:mm:ss

0 00:05:00 days hh:mm:ss

0 00:05:00 days hh:mm:ss

30 seconds

Number of Elements Qty

Rainfall Details

SN Rain Gage Data Data Source Rainfall Rain State County Return Rainfall Rainfall

ID Source ID Type Units Period Depth Distribution

(years) (inches)

1 Rain Gage-01 Time Series 005-Yr Cumulative inches 0.00

Antecedent Dry Days

File Name

Flow Units

Elevation Type

Hydrology Method

Time of Concentration (TOC) Method

Link Routing Method

Enable Overflow Ponding at Nodes

Skip Steady State Analysis Time Periods

Start Analysis On

End Analysis On

Start Reporting On

Storage Nodes

Runoff (Dry Weather) Time Step

Runoff (Wet Weather) Time Step

Reporting Time Step

Routing Time Step

Rain Gages

Subbasins

Nodes

Junctions

Outfalls

Flow Diversions

Inlets

Outlets

Pollutants

Land Uses

Links

Channels

Pipes

Pumps

Orifices

Weirs

Subbasin Summary

Subbasin Area Weighted Total Total Total Peak Time of

ID Curve Rainfall Runoff Runoff Runoff Concentration

Number Volume

(ac) (in) (in) (ac-in) (cfs) (days hh:mm:ss)

Direct 84.00 83.70 3.80 2.17 182.36 150.09 0 00:36:45

Lateral2 60.00 83.70 3.80 2.17 130.26 66.63 0 01:16:10

Lateral3 142.00 83.70 3.80 2.17 308.28 71.04 0 03:41:54

Lateral4 32.00 83.70 3.80 2.17 69.47 25.39 0 02:01:52

Lateral5 160.00 83.70 3.80 2.17 347.36 116.64 0 02:16:45

MainUpstream 60.00 83.70 3.80 2.17 130.26 115.75 0 00:32:10

Node Summary

Element Element Invert Peak Max HGL Max Time of Total Total Time

ID Type Elevation Inflow Elevation Surcharge Peak Flooded Flooded

Attained Depth Flooding Volume

Attained Occurrence

(ft) (cfs) (ft) (ft) (days hh:mm) (ac-in) (min)

DistrictTile-01 Junction 1244.41 4.50 1254.76 0.00 0 00:00 0.00 0.00

DistrictTile-02 Junction 1231.42 3.23 1242.57 0.00 0 00:00 0.00 0.00

DistrictTileProposed-03 Junction 1229.00 11.27 1236.71 0.00 0 00:00 0.00 0.00

WetlandOutlet-04 Junction 1230.00 9.30 1237.94 0.00 0 00:00 0.00 0.00

SurfaceOutfall Outfall 0.00 0.00 0.00

TileOutfall Outfall 1228.00 11.27 1228.00

Ponding South of Road Storage Node 1241.00 114.44 1242.95 0.00 0.00

Ponding West of Road Storage Node 1252.00 116.60 1255.28 0.00 0.00

Wetland Pool Storage Node 1232.00 282.87 1238.01 0.00 0.00

Link Summary

Element Element From To (Outlet) Length Inlet Outlet Average Diameter or Manning's Peak Design Flow

ID Type (Inlet) Node Invert Invert Slope Height Roughness Flow Capacity

Node Elevation Elevation

(ft) (ft) (ft) (%) (in) (cfs) (cfs)

AppleAveCulvert Pipe Ponding West of Road Wetland Pool 80.00 1254.00 1253.90 0.1200 48.000 0.0150 10.20 44.01

HWY18BoxCulvert Pipe Ponding South of Road Wetland Pool 180.00 1241.00 1240.50 0.2800 60.000 0.0150 66.81 366.98

Lateral5 Pipe DistrictTile-01 DistrictTileProposed-03 1600.00 1244.41 1230.38 0.8800 12.000 0.0150 3.37 2.89

ProposedWetlandOutelt Pipe WetlandOutlet-04 DistrictTileProposed-03 982.00 1230.98 1230.00 0.1000 24.000 0.0130 9.31 7.15

TileMainDownstream Pipe DistrictTileProposed-03 TileOutfall 1850.00 1230.00 1228.57 0.0800 24.000 0.0150 11.27 5.45

TileMainUpstream Pipe DistrictTile-02 DistrictTileProposed-03 1300.00 1231.42 1230.38 0.0800 12.000 0.0150 2.82 0.87

WetlandSurfaceOutflow Channel Wetland Pool SurfaceOutfall 3000.00 1239.00 1238.50 0.0200 120.000 0.0320 0.00 2251.97

Inflow to Lateral 5 Orifice Ponding West of Road DistrictTile-01 1252.00 1244.41 18.000 4.50

Inflow to Main Orifice Ponding South of Road DistrictTile-02 1241.00 1231.42 18.000 3.23

Wetland Outlet Weir Orifice Wetland Pool WetlandOutlet-04 1232.00 1230.00 18.000 9.30

RoadOverflow Weir Ponding West of Road Wetland Pool 1252.00 1232.00 0.00

Subbasin Hydrology

Subbasin : Direct

Input Data

Area (ac)

Peak Rate Factor

Weighted Curve Number ................................................... 83.7

Rain Gage ID ..................................................................... Rain Gage-01

Composite Curve Number 32 Area Soil Curve

Soil/Surface Description (acres) Group Number

- 84 - 83.7

Composite Area & Weighted CN 84 83.7

Time of Concentration

TOC Method : SCS TR-55

Sheet Flow Equation :

Tc = (0.007 * ((n * Lf)^0.8)) / ((P^0.5) * (Sf^0.4))

Where :

Tc = Time of Concentration (hr) n = Manning's roughness

Lf = Flow Length (ft)

P = 2 yr, 24 hr Rainfall (inches)

Sf = Slope (ft/ft)

Shallow Concentrated Flow Equation :

V = 16.1345 * (Sf^0.5) (unpaved surface)

V = 20.3282 * (Sf^0.5) (paved surface)

V = 15.0 * (Sf^0.5) (grassed waterway surface)

V = 10.0 * (Sf^0.5) (nearly bare & untilled surface)

V = 9.0 * (Sf^0.5) (cultivated straight rows surface)

V = 7.0 * (Sf^0.5) (short grass pasture surface)

V = 5.0 * (Sf^0.5) (woodland surface)

V = 2.5 * (Sf^0.5) (forest w/heavy litter surface)

Tc = (Lf / V) / (3600 sec/hr)

Where:

Tc = Time of Concentration (hr)

Lf = Flow Length (ft)

V = Velocity (ft/sec)

Sf = Slope (ft/ft)

Channel Flow Equation :

V = (1.49 * (R^(2/3)) * (Sf^0.5)) / n

R = Aq / Wp

Tc = (Lf / V) / (3600 sec/hr)

Where :

Tc = Time of Concentration (hr)

Lf = Flow Length (ft)

R = Hydraulic Radius (ft)

Aq = Flow Area (ft²)

Wp = Wetted Perimeter (ft)

V = Velocity (ft/sec)

Sf = Slope (ft/ft) n = Manning's roughness

Subarea Subarea Subarea

Sheet Flow Computations A B C

Manning's Roughness : 0.18 0 0

Flow Length (ft) : 100 0 0

Slope (%) : 2 0 0

2 yr, 24 hr Rainfall (in) : 2.98 0 0

Velocity (ft/sec) : 0.14 0 0

Computed Flow Time (min) : 11.75 0 0

Subarea Subarea Subarea

Shallow Concentrated Flow Computations A B C

Flow Length (ft) : 1200 0 0

Slope (%) : 0.8 0 0

Surface Type : Straight rows Unpaved Unpaved

Velocity (ft/sec) : 0.8 0 0

Computed Flow Time (min) : 25 0 0

Total TOC (min) ..................36.75

Subbasin Runoff Results

Total Rainfall (in) ............................................................... 3.8

Total Runoff (in) ................................................................ 2.17

Peak Runoff (cfs) .............................................................. 150.09

Weighted Curve Number ................................................... 83.7

Time of Concentration (days hh:mm:ss) ............................. 0 00:36:45

Runoff Hydrograph

Time (hrs)

1601501401301201101009080706050403020100

R u n o ff c fs

Subbasin : Lateral2

Input Data

Area (ac)

Peak Rate Factor

Weighted Curve Number ................................................... 83.7

Rain Gage ID ..................................................................... Rain Gage-01

Composite Curve Number 32 Area Soil Curve

Soil/Surface Description (acres) Group Number

- 60 - 83.7

Composite Area & Weighted CN 60 83.7

Time of Concentration

Subarea Subarea Subarea

Sheet Flow Computations A B C

Manning's Roughness : 0.18 0 0

Flow Length (ft) : 100 0 0

Slope (%) : 1 0 0

2 yr, 24 hr Rainfall (in) : 2.98 0 0

Velocity (ft/sec) : 0.11 0 0

Computed Flow Time (min) : 15.5 0 0

Subarea Subarea Subarea

Shallow Concentrated Flow Computations A B C

Flow Length (ft) : 2330 0 0

Slope (%) : 0.5 0 0

Surface Type : Straight rows Unpaved Unpaved

Velocity (ft/sec) : 0.64 0 0

Computed Flow Time (min) : 60.68 0 0

Total TOC (min) ..................76.18

Subbasin Runoff Results

Total Rainfall (in) ............................................................... 3.8

Total Runoff (in) ................................................................ 2.17

Peak Runoff (cfs) .............................................................. 66.63

Time of Concentration (days hh:mm:ss) ............................. 0 01:16:11

Time (hrs)

1601501401301201101009080706050403020100

R u n o ff c fs

Subbasin : Lateral3

Area (ac)

Peak Rate Factor

Weighted Curve Number ................................................... 83.7

Rain Gage ID ..................................................................... Rain Gage-01

Composite Curve Number 32 Area Soil Curve

Soil/Surface Description (acres) Group Number

- 142 - 83.7

Composite Area & Weighted CN 142 83.7

Time of Concentration

Subarea Subarea Subarea

Sheet Flow Computations A B C

Manning's Roughness : 0.18 0 0

Flow Length (ft) : 100 0 0

Slope (%) : 1 0 0

2 yr, 24 hr Rainfall (in) : 2.98 0 0

Velocity (ft/sec) : 0.11 0 0

Computed Flow Time (min) : 15.5 0 0

Subarea Subarea Subarea

Shallow Concentrated Flow Computations A B C

Flow Length (ft) : 5573 0 0

Slope (%) : 0.25 0 0

Surface Type : Straight rows Unpaved Unpaved

Velocity (ft/sec) : 0.45 0 0

Computed Flow Time (min) : 206.41 0 0

Total TOC (min) ..................221.91

Subbasin Runoff Results

Total Rainfall (in) ............................................................... 3.8

Total Runoff (in) ................................................................ 2.17

Peak Runoff (cfs) .............................................................. 71.04

Time of Concentration (days hh:mm:ss) ............................. 0 03:41:55

Time (hrs)

1601501401301201101009080706050403020100

R u n o ff c fs

Subbasin : Lateral4

Area (ac)

Peak Rate Factor

Weighted Curve Number ................................................... 83.7

Rain Gage ID ..................................................................... Rain Gage-01

Composite Curve Number 32 Area Soil Curve

Soil/Surface Description (acres) Group Number

- 32 - 83.7

Composite Area & Weighted CN 32 83.7

Time of Concentration

Subarea Subarea Subarea

Sheet Flow Computations A B C

Manning's Roughness : 0.18 0 0

Flow Length (ft) : 100 0 0

Slope (%) : 1 0 0

2 yr, 24 hr Rainfall (in) : 2.98 0 0

Velocity (ft/sec) : 0.11 0 0

Computed Flow Time (min) : 15.5 0 0

Subarea Subarea Subarea

Shallow Concentrated Flow Computations A B C

Flow Length (ft) : 3000 0 0

Slope (%) : 0.27 0 0

Surface Type : Straight rows Unpaved Unpaved

Velocity (ft/sec) : 0.47 0 0

Computed Flow Time (min) : 106.38 0 0

Total TOC (min) ..................121.88

Subbasin Runoff Results

Total Rainfall (in) ............................................................... 3.8

Total Runoff (in) ................................................................ 2.17

Peak Runoff (cfs) .............................................................. 25.39

Time of Concentration (days hh:mm:ss) ............................. 0 02:01:53

Time (hrs)

1601501401301201101009080706050403020100

R u n o ff c fs

Subbasin : Lateral5

Area (ac)

Peak Rate Factor

Weighted Curve Number ................................................... 83.7

Rain Gage ID ..................................................................... Rain Gage-01

Composite Curve Number 32 Area Soil Curve

Soil/Surface Description (acres) Group Number

- 160 - 83.7

Composite Area & Weighted CN 160 83.7

Time of Concentration

Subarea Subarea Subarea

Sheet Flow Computations A B C

Manning's Roughness : 0.18 0 0

Flow Length (ft) : 100 0 0

Slope (%) : 3 0 0

2 yr, 24 hr Rainfall (in) : 2.98 0 0

Velocity (ft/sec) : 0.17 0 0

Computed Flow Time (min) : 9.99 0 0

Subarea Subarea Subarea

Shallow Concentrated Flow Computations A B C

Flow Length (ft) : 5400 0 0

Slope (%) : 0.63 0 0

Surface Type : Straight rows Unpaved Unpaved

Velocity (ft/sec) : 0.71 0 0

Computed Flow Time (min) : 126.76 0 0

Total TOC (min) ..................136.75

Subbasin Runoff Results

Total Rainfall (in) ............................................................... 3.8

Total Runoff (in) ................................................................ 2.17

Peak Runoff (cfs) .............................................................. 116.64

Time of Concentration (days hh:mm:ss) ............................. 0 02:16:45

Time (hrs)

1601501401301201101009080706050403020100

R u n o ff c fs

Subbasin : MainUpstream

Area (ac)

Peak Rate Factor

Weighted Curve Number ................................................... 83.7

Rain Gage ID ..................................................................... Rain Gage-01

Composite Curve Number 32 Area Soil Curve

Soil/Surface Description (acres) Group Number

- 60 - 83.7

Composite Area & Weighted CN 60 83.7

Time of Concentration

Subarea Subarea Subarea

Sheet Flow Computations A B C

Manning's Roughness : 0.18 0 0

Flow Length (ft) : 100 0 0

Slope (%) : 3 0 0

2 yr, 24 hr Rainfall (in) : 2.98 0 0

Velocity (ft/sec) : 0.17 0 0

Computed Flow Time (min) : 9.99 0 0

Subarea Subarea Subarea

Shallow Concentrated Flow Computations A B C

Flow Length (ft) : 1850 0 0

Slope (%) : 2.37 0 0

Surface Type : Straight rows Unpaved Unpaved

Velocity (ft/sec) : 1.39 0 0

Computed Flow Time (min) : 22.18 0 0

Total TOC (min) ..................32.17

Subbasin Runoff Results

Total Rainfall (in) ............................................................... 3.8

Total Runoff (in) ................................................................ 2.17

Peak Runoff (cfs) .............................................................. 115.75

Time of Concentration (days hh:mm:ss) ............................. 0 00:32:10

Time (hrs)

1601501401301201101009080706050403020100

R u n o ff c fs

Storage Nodes

Storage Node : Ponding South of Road

Input Data

1241.00

1260.00

19.00

0.00

-1241.00

0.00

0.00

Storage Area Volume Curves Storage Curve : SouthStorage

Stage Storage Storage

Area Volume

(ft) (ft²) (ft³)

0 13252 0

1 46972 30112

2 114763 110979.5

3 214391 275556.5

4 271472 518488

5 343212 825830

6 390164 1192518

7 427512 1601356

Invert Elevation (ft)

Max (Rim) Elevation (ft)

Max (Rim) Offset (ft)

Initial Water Elevation (ft)

Initial Water Depth (ft)

Ponded Area (ft²)

Evaporation Loss

Storage Area Volume Curves

Storage Area Storage Volume

Storage Area (ft²)

400,000350,000300,000250,000200,000150,000100,00050,000

Storage Volume (ft³)

1,600,0001,400,0001,200,0001,000,000800,000600,000400,000200,0000

S ta g e ft

6.8

6.6

6.4

6.2

5.8

5.6

5.4

5.2

4.8

4.6

4.4

4.2

3.8

3.6

3.4

3.2

2.8

2.6

2.4

2.2

1.8

1.6

1.4

1.2

0.8

0.6

0.4

0.2

S ta g e ft

6.8

6.6

6.4

6.2

5.8

5.6

5.4

5.2

4.8

4.6

4.4

4.2

3.8

3.6

3.4

3.2

2.8

2.6

2.4

2.2

1.8

1.6

1.4

1.2

0.8

0.6

0.4

0.2

Storage Node : Ponding South of Road (continued)

Outflow Orifices

Element Orifice Orifice Flap Circular Rectangular Rectangular Orifice Orifice

ID Type Shape Gate Orifice Orifice Orifice Invert Coefficient

Diameter Height Width Elevation

(in) (in) (in) (ft)

Inflow to Main Bottom CIRCULAR No 18.00 0.00 0.61

Output Summary Results

114.44

114.44

69.25

1242.95

1.95

1241.07

0.07

0 12:45

Max HGL Elevation Attained (ft)

Peak Inflow (cfs)

Peak Lateral Inflow (cfs)

Peak Outflow (cfs)

Peak Exfiltration Flow Rate (cfm)

Max HGL Depth Attained (ft)

Average HGL Elevation Attained (ft)

Average HGL Depth Attained (ft)

Time of Max HGL Occurrence (days hh:mm)

Total Exfiltration Volume (1000-ft³)

Total Flooded Volume (ac-in)

Total Time Flooded (min)

Total Retention Time (sec)

Storage Node : Ponding West of Road

1252.00

1265.00

13.00

0.00

-1252.00

0.00

0.00

Storage Area Volume Curves Storage Curve : WestStorage

Stage Storage Storage

Area Volume

(ft) (ft²) (ft³)

0 13508 0

1 131190 72349

2 265985 270936.5

3 620346 714102

4 1007843 1528196.5

4.5 1200000 2080157.25

Initial Water Elevation (ft)

Invert Elevation (ft)

Max (Rim) Elevation (ft)

Max (Rim) Offset (ft)

Initial Water Depth (ft)

Storage Area (ft²)

1,200,0001,100,0001,000,000900,000800,000700,000600,000500,000400,000300,000200,000100,000

Storage Volume (ft³)

2,000,0001,500,0001,000,000500,0000

S ta g e ft

4.5

4.4

4.3

4.2

4.1

3.9

3.8

3.7

3.6

3.5

3.4

3.3

3.2

3.1

2.9

2.8

2.7

2.6

2.5

2.4

2.3

2.2

2.1

1.9

1.8

1.7

1.6

1.5

1.4

1.3

1.2

1.1

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

S ta g e ft

4.5

4.4

4.3

4.2

4.1

3.9

3.8

3.7

3.6

3.5

3.4

3.3

3.2

3.1

2.9

2.8

2.7

2.6

2.5

2.4

2.3

2.2

2.1

1.9

1.8

1.7

1.6

1.5

1.4

1.3

1.2

1.1

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

Storage Node : Ponding West of Road (continued)

Outflow Weirs

Element Weir Flap Crest Crest Length Weir Total Discharge

ID Type Gate Elevation Offset Height Coefficient

(ft) (ft) (ft) (ft)

RoadOverflow Trapezoidal No 1256.00 4.00 240.00 100.00 3.33

Outflow Orifices

Element Orifice Orifice Flap Circular Rectangular Rectangular Orifice Orifice

ID Type Shape Gate Orifice Orifice Orifice Invert Coefficient

Diameter Height Width Elevation

(in) (in) (in) (ft)

Inflow to Lateral 5 Bottom CIRCULAR No 18.00 0.00 0.61

Output Summary Results

116.6

116.6

13.46

1255.28

3.28

1253.37

1.37

0 17:29

Time of Max HGL Occurrence (days hh:mm)

Peak Inflow (cfs)

Peak Lateral Inflow (cfs)

Peak Outflow (cfs)

Peak Exfiltration Flow Rate (cfm)

Max HGL Elevation Attained (ft)

Max HGL Depth Attained (ft)

Average HGL Elevation Attained (ft)

Average HGL Depth Attained (ft)

Total Exfiltration Volume (1000-ft³)

Total Flooded Volume (ac-in)

Storage Node : Wetland Pool

1232.00

1250.00

18.00

1233.00

1.00

0.00

0.00

Storage Area Volume Curves Storage Curve : Wetland

Stage Storage Storage

Area Volume

(ft) (ft²) (ft³)

0 262400 0

1 274400 268400

3 298900 841700

4 706200 1344250

5 931200 2162950

6 1142900 3200000

7 1315000 4428950

8 1448600 5810750

9 1569700 7319900

10 1665900 8937700

Invert Elevation (ft)

Max (Rim) Elevation (ft)

Max (Rim) Offset (ft)

Initial Water Elevation (ft)

Initial Water Depth (ft)

Storage Area (ft²)

1,600,0001,400,0001,200,0001,000,000800,000600,000400,000

Storage Volume (ft³)

9,000,0008,000,0007,000,0006,000,0005,000,0004,000,0003,000,0002,000,0001,000,0000

S ta g e ft

9.8

9.6 9.4 9.2

8.8 8.6 8.4 8.2

7.8 7.6 7.4

7.2

6.8 6.6

6.4 6.2

5.8

5.6 5.4 5.2

4.8 4.6 4.4

4.2

3.8 3.6

3.4 3.2

2.8

2.6 2.4 2.2

1.8 1.6 1.4 1.2

0.8 0.6 0.4

0.2

S ta g e ft

9.8

9.6 9.4 9.2

8.8 8.6 8.4 8.2

7.8 7.6 7.4

7.2 6.8 6.6

6.4 6.2 5.8

5.6 5.4 5.2

4.8 4.6 4.4

4.2 3.8 3.6

3.4 3.2 2.8

2.6 2.4 2.2

1.8 1.6 1.4 1.2

0.8 0.6 0.4

Storage Node : Wetland Pool (continued)

Element Orifice Orifice Flap Circular Rectangular Rectangular Orifice Orifice

ID Type Shape Gate Orifice Orifice Orifice Invert Coefficient

Diameter Height Width Elevation

(in) (in) (in) (ft)

Wetland Outlet Weir Side Rectangular No 18.00 48.00 1233.00 0.63

Output Summary Results

282.87

217.34

9.3

1238.01

6.01

1236.08

4.08

1 02:16

Peak Inflow (cfs)

Total Retention Time (sec)

Peak Lateral Inflow (cfs)

Peak Outflow (cfs)

Peak Exfiltration Flow Rate (cfm)

Max HGL Elevation Attained (ft)

Max HGL Depth Attained (ft)

Average HGL Elevation Attained (ft)

Average HGL Depth Attained (ft)

Time of Max HGL Occurrence (days hh:mm)

Total Exfiltration Volume (1000-ft³)

Total Flooded Volume (ac-in)

Project Options

CFS

Elevation

SCS TR-55

SCS TR-55

Hydrodynamic

NO

NO

Analysis Options

00:00:00 0:00:00

00:00:00 0:00:00

00:00:00 0:00:00

0 days

0 01:00:00 days hh:mm:ss

0 00:05:00 days hh:mm:ss

0 00:05:00 days hh:mm:ss

30 seconds

Number of Elements Qty

Rainfall Details

SN Rain Gage Data Data Source Rainfall Rain State County Return Rainfall Rainfall

ID Source ID Type Units Period Depth Distribution

(years) (inches)

1 Rain Gage-01 Time Series 010-Yr Cumulative inches 0.00

Antecedent Dry Days

File Name

Flow Units

Elevation Type

Hydrology Method

Time of Concentration (TOC) Method

Link Routing Method

Enable Overflow Ponding at Nodes

Skip Steady State Analysis Time Periods

Start Analysis On

End Analysis On

Start Reporting On

Storage Nodes

Runoff (Dry Weather) Time Step

Runoff (Wet Weather) Time Step

Reporting Time Step

Routing Time Step

Rain Gages

Subbasins

Nodes

Junctions

Outfalls

Flow Diversions

Inlets

Outlets

Pollutants

Land Uses

Links

Channels

Pipes

Pumps

ID Curve Rainfall Runoff Runoff Runoff Concentration

Number Volume

(ac) (in) (in) (ac-in) (cfs) (days hh:mm:ss)

Direct 84.00 83.70 4.60 2.88 241.84 198.95 0 00:36:45

Lateral2 60.00 83.70 4.60 2.88 172.74 88.77 0 01:16:10

Lateral3 142.00 83.70 4.60 2.88 408.82 94.51 0 03:41:54

Lateral4 32.00 83.70 4.60 2.88 92.13 33.74 0 02:01:52

Lateral5 160.00 83.70 4.60 2.88 460.64 155.15 0 02:16:45

MainUpstream 60.00 83.70 4.60 2.88 172.74 153.32 0 00:32:10

ID Type Elevation Inflow Elevation Surcharge Peak Flooded Flooded

Attained Depth Flooding Volume

Attained Occurrence

(ft) (cfs) (ft) (ft) (days hh:mm) (ac-in) (min)

DistrictTile-01 Junction 1244.41 4.26 1255.11 0.00 0 00:00 0.00 0.00

DistrictTile-02 Junction 1231.42 2.99 1242.89 0.00 0 00:00 0.00 0.00

DistrictTileProposed-03 Junction 1229.00 11.93 1237.43 0.00 0 00:00 0.00 0.00

WetlandOutlet-04 Junction 1230.00 10.04 1238.88 0.00 0 00:00 0.00 0.00

SurfaceOutfall Outfall 0.00 0.00 0.00

TileOutfall Outfall 1228.00 11.93 1228.00

Ponding South of Road Storage Node 1241.00 151.26 1243.29 0.00 0.00

Ponding West of Road Storage Node 1252.00 154.83 1255.63 0.00 0.00

Wetland Pool Storage Node 1232.00 368.67 1238.96 0.00 0.00

ID Type (Inlet) Node Invert Invert Slope Height Roughness Flow Capacity

Node Elevation Elevation

(ft) (ft) (ft) (%) (in) (cfs) (cfs)

AppleAveCulvert Pipe Ponding West of Road Wetland Pool 80.00 1254.00 1253.90 0.1200 48.000 0.0150 16.47 44.01

HWY18BoxCulvert Pipe Ponding South of Road Wetland Pool 180.00 1241.00 1240.50 0.2800 60.000 0.0150 84.82 366.98

Lateral5 Pipe DistrictTile-01 DistrictTileProposed-03 1600.00 1244.41 1230.38 0.8800 12.000 0.0150 3.35 2.89

ProposedWetlandOutelt Pipe WetlandOutlet-04 DistrictTileProposed-03 982.00 1230.98 1230.00 0.1000 24.000 0.0130 10.05 7.15

TileMainDownstream Pipe DistrictTileProposed-03 TileOutfall 1850.00 1230.00 1228.57 0.0800 24.000 0.0150 11.93 5.45

TileMainUpstream Pipe DistrictTile-02 DistrictTileProposed-03 1300.00 1231.42 1230.38 0.0800 12.000 0.0150 2.61 0.87

WetlandSurfaceOutflow Channel Wetland Pool SurfaceOutfall 3000.00 1239.00 1238.50 0.0200 120.000 0.0320 0.00 2251.97

Inflow to Lateral 5 Orifice Ponding West of Road DistrictTile-01 1252.00 1244.41 18.000 4.26

Inflow to Main Orifice Ponding South of Road DistrictTile-02 1241.00 1231.42 18.000 2.99

Wetland Outlet Weir Orifice Wetland Pool WetlandOutlet-04 1232.00 1230.00 18.000 10.04

RoadOverflow Weir Ponding West of Road Wetland Pool 1252.00 1232.00 0.00

Input Data

Area (ac)

Peak Rate Factor

Weighted Curve Number ................................................... 83.7

Rain Gage ID ..................................................................... Rain Gage-01

Composite Curve Number 32 Area Soil Curve

Soil/Surface Description (acres) Group Number

- 84 - 83.7

Composite Area & Weighted CN 84 83.7

Time of Concentration

TOC Method : SCS TR-55

Sheet Flow Equation :

Tc = (0.007 * ((n * Lf)^0.8)) / ((P^0.5) * (Sf^0.4))

Where :

Tc = Time of Concentration (hr) n = Manning's roughness

Lf = Flow Length (ft)

P = 2 yr, 24 hr Rainfall (inches)

Sf = Slope (ft/ft)

Shallow Concentrated Flow Equation :

V = 16.1345 * (Sf^0.5) (unpaved surface)

V = 20.3282 * (Sf^0.5) (paved surface)

V = 15.0 * (Sf^0.5) (grassed waterway surface)

V = 10.0 * (Sf^0.5) (nearly bare & untilled surface)

V = 9.0 * (Sf^0.5) (cultivated straight rows surface)

V = 7.0 * (Sf^0.5) (short grass pasture surface)

V = 5.0 * (Sf^0.5) (woodland surface)

V = 2.5 * (Sf^0.5) (forest w/heavy litter surface)

Tc = (Lf / V) / (3600 sec/hr)

Where:

Tc = Time of Concentration (hr)

Lf = Flow Length (ft)

V = Velocity (ft/sec)

Sf = Slope (ft/ft)

Channel Flow Equation :

V = (1.49 * (R^(2/3)) * (Sf^0.5)) / n

R = Aq / Wp

Tc = (Lf / V) / (3600 sec/hr)

Where :

Tc = Time of Concentration (hr)

Lf = Flow Length (ft)

R = Hydraulic Radius (ft)

Aq = Flow Area (ft²)

Wp = Wetted Perimeter (ft)

V = Velocity (ft/sec)

Manning's Roughness : 0.18 0 0

Flow Length (ft) : 100 0 0

Slope (%) : 2 0 0

2 yr, 24 hr Rainfall (in) : 2.98 0 0

Velocity (ft/sec) : 0.14 0 0

Computed Flow Time (min) : 11.75 0 0

Subarea Subarea Subarea

Shallow Concentrated Flow Computations A B C

Flow Length (ft) : 1200 0 0

Slope (%) : 0.8 0 0

Surface Type : Straight rows Unpaved Unpaved

Velocity (ft/sec) : 0.8 0 0

Computed Flow Time (min) : 25 0 0

Total TOC (min) ..................36.75

Subbasin Runoff Results

Total Rainfall (in) ............................................................... 4.6

Total Runoff (in) ................................................................ 2.88

Peak Runoff (cfs) .............................................................. 198.95

Time (hrs)

1601501401301201101009080706050403020100

R u n o ff c fs

Area (ac)

Peak Rate Factor

Weighted Curve Number ................................................... 83.7

Rain Gage ID ..................................................................... Rain Gage-01

Composite Curve Number 32 Area Soil Curve

Soil/Surface Description (acres) Group Number

- 60 - 83.7

Composite Area & Weighted CN 60 83.7

Time of Concentration

Subarea Subarea Subarea

Sheet Flow Computations A B C

Manning's Roughness : 0.18 0 0

Flow Length (ft) : 100 0 0

Slope (%) : 1 0 0

2 yr, 24 hr Rainfall (in) : 2.98 0 0

Velocity (ft/sec) : 0.11 0 0

Computed Flow Time (min) : 15.5 0 0

Subarea Subarea Subarea

Shallow Concentrated Flow Computations A B C

Flow Length (ft) : 2330 0 0

Slope (%) : 0.5 0 0

Surface Type : Straight rows Unpaved Unpaved

Velocity (ft/sec) : 0.64 0 0

Computed Flow Time (min) : 60.68 0 0

Total TOC (min) ..................76.18

Subbasin Runoff Results

Total Rainfall (in) ............................................................... 4.6

Total Runoff (in) ................................................................ 2.88

Peak Runoff (cfs) .............................................................. 88.77

Time (hrs)

1601501401301201101009080706050403020100

R u n o ff c fs

Area (ac)

Peak Rate Factor

Weighted Curve Number ................................................... 83.7

Rain Gage ID ..................................................................... Rain Gage-01

Composite Curve Number 32 Area Soil Curve

Soil/Surface Description (acres) Group Number

- 142 - 83.7

Composite Area & Weighted CN 142 83.7

Time of Concentration

Subarea Subarea Subarea

Sheet Flow Computations A B C

Manning's Roughness : 0.18 0 0

Flow Length (ft) : 100 0 0

Slope (%) : 1 0 0

2 yr, 24 hr Rainfall (in) : 2.98 0 0

Velocity (ft/sec) : 0.11 0 0

Computed Flow Time (min) : 15.5 0 0

Subarea Subarea Subarea

Shallow Concentrated Flow Computations A B C

Flow Length (ft) : 5573 0 0

Slope (%) : 0.25 0 0

Surface Type : Straight rows Unpaved Unpaved

Velocity (ft/sec) : 0.45 0 0

Computed Flow Time (min) : 206.41 0 0

Total TOC (min) ..................221.91

Subbasin Runoff Results

Total Rainfall (in) ............................................................... 4.6

Total Runoff (in) ................................................................ 2.88

Peak Runoff (cfs) .............................................................. 94.51

Time (hrs)

1601501401301201101009080706050403020100

R u n o ff c fs

Area (ac)

Peak Rate Factor

Weighted Curve Number ................................................... 83.7

Rain Gage ID ..................................................................... Rain Gage-01

Composite Curve Number 32 Area Soil Curve

Soil/Surface Description (acres) Group Number

- 32 - 83.7

Composite Area & Weighted CN 32 83.7

Time of Concentration

Subarea Subarea Subarea

Sheet Flow Computations A B C

Manning's Roughness : 0.18 0 0

Flow Length (ft) : 100 0 0

Slope (%) : 1 0 0

2 yr, 24 hr Rainfall (in) : 2.98 0 0

Velocity (ft/sec) : 0.11 0 0

Computed Flow Time (min) : 15.5 0 0

Subarea Subarea Subarea

Shallow Concentrated Flow Computations A B C

Flow Length (ft) : 3000 0 0

Slope (%) : 0.27 0 0

Surface Type : Straight rows Unpaved Unpaved

Velocity (ft/sec) : 0.47 0 0

Computed Flow Time (min) : 106.38 0 0

Total TOC (min) ..................121.88

Subbasin Runoff Results

Total Rainfall (in) ............................................................... 4.6

Total Runoff (in) ................................................................ 2.88

Peak Runoff (cfs) .............................................................. 33.74

Time (hrs)

1601501401301201101009080706050403020100

R u n o ff c fs

Area (ac)

Peak Rate Factor

Weighted Curve Number ................................................... 83.7

Rain Gage ID ..................................................................... Rain Gage-01

Composite Curve Number 32 Area Soil Curve

Soil/Surface Description (acres) Group Number

- 160 - 83.7

Composite Area & Weighted CN 160 83.7

Time of Concentration

Subarea Subarea Subarea

Sheet Flow Computations A B C

Manning's Roughness : 0.18 0 0

Flow Length (ft) : 100 0 0

Slope (%) : 3 0 0

2 yr, 24 hr Rainfall (in) : 2.98 0 0

Velocity (ft/sec) : 0.17 0 0

Computed Flow Time (min) : 9.99 0 0

Subarea Subarea Subarea

Shallow Concentrated Flow Computations A B C

Flow Length (ft) : 5400 0 0

Slope (%) : 0.63 0 0

Surface Type : Straight rows Unpaved Unpaved

Velocity (ft/sec) : 0.71 0 0

Computed Flow Time (min) : 126.76 0 0

Total TOC (min) ..................136.75

Subbasin Runoff Results

Total Rainfall (in) ............................................................... 4.6

Total Runoff (in) ................................................................ 2.88

Peak Runoff (cfs) .............................................................. 155.15

Time (hrs)

1601501401301201101009080706050403020100

R u n o ff c fs

Area (ac)

Peak Rate Factor

Weighted Curve Number ................................................... 83.7

Rain Gage ID ..................................................................... Rain Gage-01

Composite Curve Number 32 Area Soil Curve

Soil/Surface Description (acres) Group Number

- 60 - 83.7

Composite Area & Weighted CN 60 83.7

Time of Concentration

Subarea Subarea Subarea

Sheet Flow Computations A B C

Manning's Roughness : 0.18 0 0

Flow Length (ft) : 100 0 0

Slope (%) : 3 0 0

2 yr, 24 hr Rainfall (in) : 2.98 0 0

Velocity (ft/sec) : 0.17 0 0

Computed Flow Time (min) : 9.99 0 0

Subarea Subarea Subarea

Shallow Concentrated Flow Computations A B C

Flow Length (ft) : 1850 0 0

Slope (%) : 2.37 0 0

Surface Type : Straight rows Unpaved Unpaved

Velocity (ft/sec) : 1.39 0 0

Computed Flow Time (min) : 22.18 0 0

Total TOC (min) ..................32.17

Subbasin Runoff Results

Total Rainfall (in) ............................................................... 4.6

Total Runoff (in) ................................................................ 2.88

Peak Runoff (cfs) .............................................................. 153.32

Time (hrs)

1601501401301201101009080706050403020100

R u n o ff c fs

Input Data

1241.00

1260.00

19.00

0.00

-1241.00

0.00

0.00

Storage Area Volume Curves Storage Curve : SouthStorage

Stage Storage Storage

Area Volume

(ft) (ft²) (ft³)

0 13252 0

1 46972 30112

2 114763 110979.5

3 214391 275556.5

4 271472 518488

5 343212 825830

6 390164 1192518

7 427512 1601356

Invert Elevation (ft)

Max (Rim) Elevation (ft)

Max (Rim) Offset (ft)

Initial Water Elevation (ft)

Initial Water Depth (ft)

Storage Area (ft²)

400,000350,000300,000250,000200,000150,000100,00050,000

Storage Volume (ft³)

1,600,0001,400,0001,200,0001,000,000800,000600,000400,000200,0000

S ta g e ft

6.8

6.6

6.4

6.2

5.8

5.6

5.4

5.2

4.8

4.6

4.4

4.2

3.8

3.6

3.4

3.2

2.8

2.6

2.4

2.2

1.8

1.6

1.4

1.2

0.8

0.6

0.4

0.2

S ta g e ft

6.8

6.6

6.4

6.2

5.8

5.6

5.4

5.2

4.8

4.6

4.4

4.2

3.8

3.6

3.4

3.2

2.8

2.6

2.4

2.2

1.8

1.6

1.4

1.2

0.8

0.6

0.4

Element Orifice Orifice Flap Circular Rectangular Rectangular Orifice Orifice

ID Type Shape Gate Orifice Orifice…