26-10_CAR833409A_Design_Report.pdf

PDF 2 MB Posted Sep 30, 2026

Attached to: 26-10 Car833409A (Carroll)
Solicitation number: 009-RFB-WRBWL-CY26-10
Issued by: Carroll County, Iowa

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Written by GovTribe AI · Oct 12, 2026

Design Report Summary

This is a Wetland Design Report prepared by Bolton & Menk, Inc. for the Iowa Department of Agriculture and Land Stewardship (IDALS), Division of Soil and Water Quality, detailing the design specifications for the Thrills Hills nutrient reduction wetland project (Site No. CAR833409A) located in Carroll County, Iowa. The project will construct a wetland improvement facility on property owned by Thrills Hills LLC, approximately four miles southeast of Carroll, Iowa, designed to reduce nitrates in water from an unnamed tributary of the Middle Raccoon River through natural denitrification processes. The scope of work includes excavation and construction of a permanent wetland pool of approximately 3.49 acres with a normal storage capacity of 4.11 acre-feet, installation of diversion berms to optimize water mixing, construction of a rectangular outlet structure and 36-inch reinforced concrete pipe discharge system, and an earthen auxiliary spillway designed to handle storm events up to and exceeding the 100-year rainfall event. The facility will utilize a solar-powered 3 HP pump system to divert stream water into the wetland, with the design based on a direct surface-drained watershed of 50.4 acres and a larger stream watershed of 2,106 acres. The embankment will be 6.5 feet in height with a normal pool elevation of 1,217.00 feet NAVD88, and the design incorporates one foot of freeboard during the 100-year storm event. The project follows Iowa NRCS Conservation Practice Standard 656 (dated December 2023) and is classified as NRCS Job Class III. Construction is scheduled to commence within seven days of the preconstruction meeting with a deadline of September 1, 2027, with seeding to be completed by December 15, 2027.

The facility does not require an Iowa DNR dam construction permit, as it meets low-hazard criteria with a height of 6.5 feet and storage of 15.4 acre-feet at the top of the dam. The project will be permitted under Army Regional Permit 39, with IDALS obtaining necessary permits and easement recording for the permanent easement on Thrills Hills LLC property. Hydrologic analysis utilizing HydroCAD modeling demonstrates that the wetland will provide 31.9% capture of the 9-month average tile flow and will effectively attenuate peak flows across all design storms, with outflow rates of 43.80 cfs, 59.84 cfs, 87.06 cfs, and 108.89 cfs for the 5-year, 10-year, 25-year, and 100-year events respectively. Soil conditions at the site are predominantly loam (Ida silt loam, Terril loam, Colo silt loam, Burchard-Adair clay loams) with hydrologic soil groups B, C, and C/D, confirmed through field sampling. The estimated construction cost range is $175,000 to $275,000, with bid security of 10% of the bid price required and a Performance/Payment Bond equal to 100% of the contract price required of the successful bidder. A pre-bid meeting is scheduled for October 6, 2026, at 11:00 AM at Carroll Public Library with virtual attendance available, and bids are due October 27, 2026, at 3:00 PM through the Iowa Management of Procurement and Contracts System (IMPACS).

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File	Type	Posted
1453281-event.pdf	PDF	Sep 30, 2026
26-10_CAR833409A_Doc CC Schedule of Prices (WORKSHEET).pdf	PDF	Sep 30, 2026
26-10_CAR833409A_Doc EE Bid Bon (UPLOAD with POA).pdf	PDF	Sep 30, 2026
26-10_CAR833409A_Doc CC Proposal-Acknowledge-Affidavit (UPLOAD).pdf	PDF	Sep 30, 2026
26-10_CAR833409A Plans 09-29-2026.pdf	PDF	Sep 30, 2026
26-10_Car833409A_Bid_Book_.pdf	PDF	Sep 30, 2026
26-10_CAR833409A Wetland QA QC Plan.pdf	PDF	Sep 30, 2026
26-10_CAR833409A_Specifications.pdf	PDF	Sep 30, 2026
26-10_Car833409A_Notice_to_Bidders.pdf	PDF	Sep 30, 2026

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H:\IDALS\25X137945000\3_Design\C_Reports\Thrills Hills Design Report.docx

February 26, 2026

Thrills Hills Wetland Design Report Site No. CAR833409A Carroll County, Iowa

Project Overview This wetland improvement is planned to provide nutrient reduction benefits to a part of the watershed of an unnamed tributary of Middle Raccoon River in Carroll County, Iowa. Nitrates will be converted to nitrogen gas through natural processes as the water passes through the wetland.

The project location is on the property of Thrills Hills LLC, roughly four miles southeast of Carroll, Iowa. A wetland pool will be created by a combination of excavation and the construction of an embankment.

Water from the stream will be pumped into the wetland to fill the pool. Diversion berms are proposed within the permanent pool to encourage mixing and reduce short-cutting of water out of the wetland.

Water will be released from the pool through the rectangular wetland outlet structure and be carried through a 36-inch reinforced concrete pipe, to be discharged into the stream. During large storm events, the pool will rise, and water will flow over the earthen auxiliary spillway, directing the outflow to the stream. Constructing the wetland will not have adverse effects on the hydrology of the neighboring properties.

Site Selection and Analysis This site was deemed viable because of the size of the stream watershed (2,106 acres) and its topography. Initial payment information was presented to the landowner, who wished to proceed with the project.

Bolton & Menk reviewed the soil survey data for the location and found the soils to be primarily loam.

The web soil survey data was confirmed with soil samples from three locations on the site. The wetland watershed was analyzed using LiDAR data. A map of the contributing watersheds is included with this report. Curve number calculations are provided in the attached hydrology report, and runoff analysis is provided in the attached HydroCAD output.

The site was surveyed with survey-grade GPS equipment, and additional topographic information was provided from a publicly available LiDAR database. LiDAR was verified with survey data. Elevations are referenced to NAVD88, and the Iowa State Plane North (Survey Foot) coordinate system was used for horizontal coordinates. Survey data was collected electronically and is available in .csv files.

Design Standards Iowa NRCS Conservation Practice Standard (CPS) 656, dated December 2023, was used to develop this project. CPS 378 (Pond) was used to design the primary outlet, auxiliary spillway, and the embankment.

The project is NRCS Job Class III under CPS 656 because the direct watershed is less than 300 acres.

Name: Thrills Hills Wetland Design Report Date: February 26, 2026 Page: 2

Project Layout A permanent pool elevation and embankment location were selected based on the existing topography and the ability to maximize pool area while minimizing excavation and the height of the embankment.

The pool was also sited to minimize impacts to the stream it is adjacent to. There is not an established regulatory floodway for the stream, but the embankment is out of the channelized area and its only encroachment into the regulatory floodplain is in a backwater area.

Watersheds were developed using contour and DEM data from a publicly available database. The wetland watershed is that from which surface water directly enters the wetland pool. The gravel pit watershed is that from which surface water enters the adjacent existing gravel pit. The gravel pit was included in the hydraulic analysis but it was shown that it will not overflow into the wetland pool. The stream watershed, which is used for the wetland treated area analysis, was determined from StreamStats. The watershed information and rainfall data were used to develop hydrographs in HydroCAD. The storm distribution used was MSE 3, with rainfall depths from the National Engineering Handbook. These hydrographs and the proposed stage-storage information were used to size the primary outlet and auxiliary spillway for the wetland. Exceeding the minimum design standards of NRCS CPS 378, the auxiliary spillway is placed above the 25-year storm, and the embankment is designed to provide at least one foot of freeboard during the 100-year storm. HydroCAD outputs are provided in the appendix.

Dam Regulation A dam construction permit is required by the Iowa DNR if it (1) has a height of at least 25 feet and a storage of 15-acre feet at the top of the dam elevation; or (2) has a storage of at least 50 acre-feet at the top of dam and a height of at least 6 feet; or (3) is assigned a hazard potential of high hazard. This dam does not require a dam construction permit because the height is 6.5 feet, the storage at the top of the dam is 15.4 acre-feet, and the hazard potential is low hazard.

The dam is classified as “low hazard” if failure of the dam would result in no probable loss of human life, low economic losses, and low public damages. This dam meets the requirements of a low hazard dam.

Land Rights and Permits The permanent easement for this project will be on the property of Thrills Hills LLC. 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.

The project will be permitted under Army Regional Permit 39. The permit will be obtained by the Iowa Department of Agriculture and Land Stewardship (IDALS). A floodplain permit application will also be obtained by IDALS if necessary. Portions of the project are within the regulatory floodplain; there is no established floodway at this location.

Sincerely, Bolton & Menk, Inc.

Brandon C. Short, PE Water Resources Project Engineer

Date: January 8, 2026 Page: 3

Appendices:

A: Soil Survey Map

B: Watershed Map

C: Hydrology Report

D: HydroCAD Output

E: Pump Curve

F: Pipe Capacity Calculations

Page: 4

Appendix A: Soil Survey Map

Page: 5

Appendix B: Watershed Map

Page: 6

Appendix C: Hydrology Report

25-year Event: 5.70'' 100-year Event: 7.90''

* Hydrologic Soil Groups: B, C, C/D

* Runoff Curve Number: 83.0 (based on Land use shown in this report)

* Primary Spillway Weir Coefficent ≈ 3.0

Hydrology Analysis Summary

Normal pool area is 3.49 acres.

Tc = 1.0 hours determined by the sum of sheet, shallow concentrated and channel flow times.

Surface watershed area is approx. 50.4 acres or 0.08 square miles.

Report Summary

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. Hydrologic data was compiled, the structure was flood routed using the SCS TR-55 method in HydroCAD, 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 rectangular outlet structure with six-foot-wide openings on all sides that discharges to the existing stream on site. The auxiliary spillway is a 30-foot earthen spillway placed above the 10-year rainfall event high water level, that also discharges to the stream.

Design Parameters and Procedures:

Summary Table:

1217.50 1218.00 1218.25 5-year 61.99 43.80 1217.69 1.3 0.0 0.0

10-year 80.07 59.84 1217.83 1.7 0.0 0.0 25-year 111.78 87.06 1218.06 2.2 0.5 0.0 100-year 170.73 108.89 1218.72 2.7 1.3 0.8

Overflow Elevation: 1235.75 (Data for Surface Flow) Duration - Hours at elevationQmax In

(cfs) Qmax Out

(cfs) Max Elev

(ft)

H:\IDALS\25X137945000\3_Design\C_Reports\Thrills Hills Hydrology Report.xlsm

IDALS ID Number: CAR833409A Job: Thrills Hills

BMI Project Number: 25X.137945 Designed By: BCS Date: 1/16/2026

Rainfall Data

Carroll

MSE 3

West Central

NEH Title 210 (Figure IA2-25)

SUDAS Design Manual 2025 Edition NOAA Atlas 14

2 3.00 3.01 3.06

5 3.80 3.74 3.79

10 4.50 4.45 4.52

25 5.70 5.59 5.69

50 6.70 6.58 6.73

100 7.90 7.67 7.88

Surface-Drained DA = 50 ac = .08 sq mi

The following rainfall data was used for the hydrology analysis of the site. Rainfall depths from the NEH Title 210 Figure IA2-25 were used, and two additional sources are shown for reference only.

County:

Storm Distribution:

Iowa Climactic Section (SUDAS):

Data Source

24-hr Rainfall Depths (in) Return Period (Years)

H:\IDALS\25X137945000\3_Design\C_Reports\Thrills Hills Hydrology Report.xlsm Page 2

BMI Project Number: 25X.137945 Designed By: BCS Date: 1/16/2026

Tributary Watershed Data

Area Area Time of Concentration

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

Direct 50 0.08 Surface 59.6

Stream (Pumped) 2106 3.29 Tile & Surface

H:\IDALS\25X137945000\3_Design\C_Reports\Thrills Hills Hydrology Report.xlsm Page 3

BMI Project Number: 25X.137945 Designed By: BCS Date: 1/16/2026

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

Ida silt loam; Terril loam B Straight Row Crops, Good 28.7% 78 22.386

Colo silt loam; et al. C Stright Row Crops, Good 37.7% 85 32.045

Burchard-Adair clay loams; et al. C/D Straight Row Crops, Good 33.6% 85 28.560

Totals: 100.0% 83.0

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

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

= .08 sq mi Runoff Curve Number Surface-Drained DA = 50 ac

H:\IDALS\25X137945000\3_Design\C_Reports\Thrills Hills Hydrology Report.xlsm Page 4

BMI Project Number: 25X.137945 Designed By: BCS Date: 1/16/2026

Stage-Storage

Contour Elev. Area Area Average

Area Incremental

Volume Cumulative

Volume Volume Above

Weir

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

1215.00 356 0.01 0.01 0.00 0.00

1215.50 5920 0.14 0.07 0.04 0.04

1216.00 136041 3.12 1.63 0.81 0.85

1216.50 139466 3.20 3.16 1.58 2.43

1217.00 152192 3.49 3.35 1.67 4.11 0.00

1217.50 155747 3.58 3.53 1.77 5.87 1.77

1218.00 159336 3.66 3.62 1.81 7.68 3.58

1218.50 162957 3.74 3.70 1.85 9.53 5.43

1219.00 167469 3.84 3.79 1.90 11.43 7.32

1219.50 171353 3.93 3.89 1.94 13.37 9.27

1220.00 176943 4.06 4.00 2.00 15.37 11.27

4.11 Acre-feet

1217.00

9.53 Acre-feet

1218.50 1.18 feet

Notes:

= .08 sq mi

Surface-Drained DA = 50 ac

Average Depth =

Storage at Normal Pool

Storage at Overflow

Elevation =

Elevation of weir = Average Depth =

Storage at Normal Pool

Area at Normal Pool

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

H:\IDALS\25X137945000\3_Design\C_Reports\Thrills Hills Hydrology Report.xlsm Page 5

BMI Project Number: 25X.137945 Designed By: BCS Date: 1/16/2026

Pump Outlet

Dia. (in) TDH (ft)

Peak Pumping Rate

(gpm)

Peak Pumping Rate (cfs)

9-Month Percent Capture

Capture Without Storage

Effective Pumped

Watershed (ac)

1.5 HP 6 11.00 225 0.50 26.9% 26.9% 566

2 HP 6 11.00 270 0.60 29.1% 29.1% 613

Selected: 3 HP 6 11.00 330 0.74 31.9% 31.9% 672

2 HP Duplex 6 11.00 540 1.20 39.2% 39.2% 825

5 HP 6 13.00 735 1.64 43.6% 43.6% 917

10 HP 8 12.00 1135 2.53 48.6% 48.6% 1024

15 HP 8 12.25 1275 2.84 49.8% 49.8% 1048

Watershed Drainage Area (ac)

9-Month Mean Tile

Flow (cfs)1

Peak Pumping Rate

(cfs)2

Adjusted Pumping Capacity

(cfs)3 % of 1/2"

% of 9- Month

Mean Tile Flow

Total 9-Month Percent Capture4

Stream 2105.6 2.64 0.73 0.23 0.5% 8.8% 31.9% Notes:

2 Maximum capacity of 3 HP pump assuming 11 ft total dynamic head.

3 Adjusts for average daylight hours and cloud cover for March through November.

4 Average capture was calculated for each month based on expected tile flow, daylight hours, and cloud cover. This percentage is the average of months March through November.

1 Calculated from USGS StreamStats flow-duration data. Estimates flows from March through November.

Average Daylight Hours: 55.7%

Not Practicable with Solar

Pump Comparison

Pump Analysis (Selected Pump)

Solar Pump Capture Calculations

0.0%

10.0%

20.0%

30.0%

40.0%

50.0%

60.0%

260 510 760 1010 1260

Ca pt ur e

Pe rc en ta ge

Pump Peak Flow (gpm)

Pump Peak Flow vs. Capture Percentage

Percent Capture Percent Daylight

H:\IDALS\25X137945000\3_Design\C_Reports\Thrills Hills Hydrology Report.xlsm Page 6

BMI Project Number: 25X.137945 Designed By: BCS Date: 1/16/2026

178851 cf

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

Stream 2105.6 31.9% 672 16248 35362 11.0 5.1

Notes:

2 Average full-sun day for pumped inlets.

3 Based on normal pool volume and average flow capture.

4 Based on normal pool volume and full flow capture.

Total Capture Calculations

Wetland Normal Pool Volume =

1 9-month average capture for pumped inlets.

H:\IDALS\25X137945000\3_Design\C_Reports\Thrills Hills Hydrology Report.xlsm Page 7

BMI Project Number: 25X.137945 Designed By: BCS Date: 1/16/2026

Weir Flow Hydraulics DA = 50 ac

= .08 sq mi

Input

Q = CLH1.5

Use C = 3.1

Output

Weir Length (ft) 15 20 24 30 35

W.S. Elev. Q - cfs Q - cfs Q - cfs Q - cfs Q - cfs

1217.00 0.0 0.0 0.0 0.0 0.0

1217.19 3.8 5.0 6.0 7.6 8.8

1217.38 10.7 14.2 17.1 21.4 24.9

1217.56 19.6 26.2 31.4 39.2 45.8

1217.75 30.2 40.3 48.3 60.4 70.5

1217.94 42.2 56.3 67.5 84.4 98.5

1218.13 55.5 74.0 88.8 111.0 129.5

1218.31 69.9 93.2 111.9 139.8 163.1

1218.50 85.4 113.9 136.7 170.9 199.3

1218.69 101.9 135.9 163.1 203.9 237.8

1218.88 119.4 159.2 191.0 238.8 278.6

1219.06 137.7 183.6 220.4 275.5 321.4

1219.25 156.9 209.3 251.1 313.9 366.2

1219.44 177.0 235.9 283.1 353.9 412.9

1219.63 197.8 263.7 316.4 395.5 461.4

1219.81 219.3 292.4 350.9 438.7 511.8

MAX POOL 1220.00 241.6 322.2 386.6 483.2 563.8

USED

Normal Pool Elev. = 1217.00

H:\IDALS\25X137945000\3_Design\C_Reports\Thrills Hills Hydrology Report.xlsm Page 8

BMI Project Number: 25X.137945 Designed By: BCS Date: 1/16/2026

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

= .08 sq miSurface-Drained DA = 50 ac

060120180240300

1215.5

1216.5

1217.5

1218.5

1219.5

0.00 1.00 2.00 3.00 4.00 5.00

Discharge (cfs)

E le va ti o n

Pool Area (ac)

Pool Area-Elevation-Discharge Graph

Normal Pool

Pool Area (ac)

Series3

1217.00

1217.20

1217.40

1217.60

1217.80

1218.00

1218.20

1218.40

1218.60

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

H:\IDALS\25X137945000\3_Design\C_Reports\Thrills Hills Hydrology Report.xlsm Page 9

BMI Project Number: 25X.137945 Designed By: BCS Date: 1/16/2026

Results

1215.00 0.01

1215.50 0.14

1216.00 3.12

1216.50 3.20

1217.00 3.49 0 0 0

1217.50 3.58 27.17 0 27.17

1218.00 3.66 85.56 0 85.56

1218.50 3.74 99.33 0.32 99.65

1219.00 3.84 102.11 29.78 131.89

1219.50 3.93 104.9 85.21 190.11

1220.00 4.06 107.63 162.65 270.28

Elevation Elevation Elevation Elevation 0 1217.69 0 1217.83 0 1218.06 0 1218.46 2 1217.39 2 1217.45 2 1217.53 2 1217.68 4 1217.20 4 1217.22 4 1217.27 4 1217.35 6 1217.13 6 1217.15 6 1217.18 6 1217.24 8 1217.10 8 1217.12 8 1217.15 8 1217.19

10 1217.08 10 1217.10 10 1217.12 10 1217.16 12 1217.06 12 1217.08 12 1217.09 12 1217.13 14 1217.04 14 1217.05 14 1217.07 14 1217.10 16 1217.02 16 1217.02 16 1217.04 16 1217.06 18 1217.02 18 1217.01 18 1217.02 18 1217.04 20 1217.01 20 1217.01 20 1217.01 20 1217.02 22 1217.01 22 1217.01 22 1217.01 22 1217.01 24 1207.01 24 1217.01 24 1217.01 24 1217.01

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) Outlet Pipe

Discharge (cfs) Aux Spillway

Discharge (cfs) Total Discharge

(cfs)

100-year Duration

5-year Duration

10-year Duration

25-year Duration

= .08 sq mi Surface-Drained DA = 50 ac

H:\IDALS\25X137945000\3_Design\C_Reports\Thrills Hills Hydrology Report.xlsm Page 10

Page: 7

Appendix D: HydroCAD Output

Direct Watershed

Gravel Pit Watershed

Wetland Pool

Gravel Pit

Routing Diagram for Thrills Hills HydroCad Prepared by Bolton & Menk, Inc, Printed 1/8/2026

Subcat Reach Pond Link

Thrills Hills HydroCad Printed 1/8/2026Prepared by Bolton & Menk, Inc

Rainfall Events Listing

Event# Event

Name

Storm Type Curve Mode Duration

(hours)

B/B Depth

(inches)

AMC

1 5-Year MSE 24-hr 3 Default 24.00 1 3.80 2

2 10-Year MSE 24-hr 3 Default 24.00 1 4.50 2

3 25-Year MSE 24-hr 3 Default 24.00 1 5.70 2

4 100-Year MSE 24-hr 3 Default 24.00 1 7.90 2

Thrills Hills HydroCad

Area Listing (all nodes)

Area

(acres)

CN Description

(subcatchment-numbers)

93.600 83 (1S, 3S)

93.600 83 TOTAL AREA

MSE 24-hr 3 5-Year Rainfall=3.80"Thrills Hills HydroCad

Time span=5.00-96.00 hrs, dt=0.05 hrs, 1821 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN

Reach routing by Stor-Ind method - Pond routing by Stor-Ind method

Runoff Area=50.400 ac 0.00% Impervious Runoff Depth=2.11"Subcatchment 1S: Direct Watershed Flow Length=2,323' Tc=59.6 min CN=83 Runoff=61.99 cfs 8.877 af

Runoff Area=43.200 ac 0.00% Impervious Runoff Depth=2.11"Subcatchment 3S: Gravel Pit Watershed Flow Length=1,659' Tc=27.6 min CN=83 Runoff=85.61 cfs 7.609 af

Peak Elev=1,217.69' Storage=6.641 af Inflow=61.99 cfs 8.877 afPond 2P: Wetland Pool Outflow=43.80 cfs 8.877 af

Peak Elev=1,215.09' Storage=7.609 af Inflow=85.61 cfs 7.609 afPond 3P: Gravel Pit Outflow=0.00 cfs 0.000 af

Total Runoff Area = 93.600 ac Runoff Volume = 16.486 af Average Runoff Depth = 2.11" 100.00% Pervious = 93.600 ac 0.00% Impervious = 0.000 ac

Summary for Subcatchment 1S: Direct Watershed

Runoff = 61.99 cfs @ 12.81 hrs, Volume= 8.877 af, Depth= 2.11" Routed to Pond 2P : Wetland Pool

Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-96.00 hrs, dt= 0.05 hrs MSE 24-hr 3 5-Year Rainfall=3.80"

Area (ac) CN Description

* 50.400 83

50.400 100.00% Pervious Area

Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs)

11.2 100 0.0200 0.15 Sheet Flow, Cultivated: Residue>20% n= 0.170 P2= 3.00"

4.3 664 0.0828 2.59 Shallow Concentrated Flow, SR Steep

Cultivated Straight Rows Kv= 9.0 fps

21.0 507 0.0020 0.40 Shallow Concentrated Flow, SR Flat

Cultivated Straight Rows Kv= 9.0 fps

18.0 770 0.0104 0.71 Shallow Concentrated Flow, Pasture

Short Grass Pasture Kv= 7.0 fps

5.1 282 0.0106 0.93 Shallow Concentrated Flow, SR

Cultivated Straight Rows Kv= 9.0 fps

59.6 2,323 Total

Subcatchment 1S: Direct Watershed

Runoff

Hydrograph

Time (hours) 9590858075706560555045403530252015105

F lo w

(c fs

MSE 24-hr 3 5-Year Rainfall=3.80"

Runoff Area=50.400 ac Runoff Volume=8.877 af

Runoff Depth=2.11" Flow Length=2,323'

Tc=59.6 min

CN=83

61.99 cfs

Summary for Subcatchment 3S: Gravel Pit Watershed

Runoff = 85.61 cfs @ 12.40 hrs, Volume= 7.609 af, Depth= 2.11" Routed to Pond 3P : Gravel Pit

Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-96.00 hrs, dt= 0.05 hrs MSE 24-hr 3 5-Year Rainfall=3.80"

Area (ac) CN Description

* 43.200 83

43.200 100.00% Pervious Area

Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs)

13.4 100 0.0100 0.12 Sheet Flow, Grass: Short n= 0.150 P2= 3.00"

0.8 108 0.0185 2.19 Shallow Concentrated Flow, Unpaved

Unpaved Kv= 16.1 fps

3.2 365 0.0438 1.88 Shallow Concentrated Flow, SR

Cultivated Straight Rows Kv= 9.0 fps

1.7 173 0.0578 1.68 Shallow Concentrated Flow, Pasture

Short Grass Pasture Kv= 7.0 fps

5.2 543 0.0368 1.73 Shallow Concentrated Flow, SR

Cultivated Straight Rows Kv= 9.0 fps

3.3 370 0.0730 1.89 Shallow Concentrated Flow, Pasture

Short Grass Pasture Kv= 7.0 fps

27.6 1,659 Total

Subcatchment 3S: Gravel Pit Watershed

Runoff

Hydrograph

Time (hours) 9590858075706560555045403530252015105

MSE 24-hr 3 5-Year Rainfall=3.80"

Runoff Area=43.200 ac Runoff Volume=7.609 af

Runoff Depth=2.11" Flow Length=1,659'

Tc=27.6 min

85.61 cfs

Summary for Pond 2P: Wetland Pool

Inflow Area = 50.400 ac, 0.00% Impervious, Inflow Depth = 2.11" for 5-Year event Inflow = 61.99 cfs @ 12.81 hrs, Volume= 8.877 af Outflow = 43.80 cfs @ 13.22 hrs, Volume= 8.877 af, Atten= 29%, Lag= 24.5 min Primary = 43.80 cfs @ 13.22 hrs, Volume= 8.877 af

Routing by Stor-Ind method, Time Span= 5.00-96.00 hrs, dt= 0.05 hrs Starting Elev= 1,217.00' Surf.Area= 3.493 ac Storage= 4.190 af Peak Elev= 1,217.69' @ 13.22 hrs Surf.Area= 3.606 ac Storage= 6.641 af (2.451 af above start)

Plug-Flow detention time= 267.8 min calculated for 4.684 af (53% of inflow) Center-of-Mass det. time= 67.1 min ( 918.7 - 851.5 )

Volume Invert Avail.Storage Storage Description #1 1,215.00' 15.437 af Custom Stage Data (Prismatic) Listed below (Recalc)

Elevation Surf.Area Inc.Store Cum.Store (feet) (acres) (acre-feet) (acre-feet)

1,215.00 0.238 0.000 0.000 1,215.50 0.380 0.155 0.155 1,216.00 3.013 0.848 1.003 1,216.50 3.122 1.534 2.536 1,217.00 3.493 1.654 4.190 1,217.50 3.575 1.767 5.957 1,218.00 3.657 1.808 7.765 1,218.50 3.740 1.849 9.614 1,219.00 3.845 1.896 11.511 1,219.50 3.914 1.940 13.451 1,220.00 4.030 1.986 15.437

Device Routing Invert Outlet Devices #1 Primary 1,208.00' 36.0" Round Culvert

L= 128.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 1,208.00' / 1,207.50' S= 0.0039 '/' Cc= 0.900 n= 0.013, Flow Area= 7.07 sf

#2 Device 1 1,217.00' 6.0' long x 0.5' breadth Broad-Crested Rectangular Weir X 4.00 Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32

#3 Primary 1,218.50' 30.0' long + 3.0 '/' SideZ x 30.0' 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

Primary OutFlow Max=43.72 cfs @ 13.22 hrs HW=1,217.69' TW=1,210.00' (Fixed TW Elev= 1,210.00') 1=Culvert (Passes 43.72 cfs of 94.38 cfs potential flow)

2=Broad-Crested Rectangular Weir (Weir Controls 43.72 cfs @ 2.64 fps) 3=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)

Pond 2P: Wetland Pool

Inflow Primary

Hydrograph

Time (hours) 9590858075706560555045403530252015105

Inflow Area=50.400 ac Peak Elev=1,217.69'

Storage=6.641 af

61.99 cfs

43.80 cfs

Pond 2P: Wetland Pool

Primary

Stage-Discharge

Discharge (cfs) 260240220200180160140120100806040200

E le va ti o n

(f ee t)

1,220

1,219

1,218

1,217

1,216

1,215

Broad-Crested Rectangular Weir

Pond 2P: Wetland Pool

Surface Storage

Stage-Area-Storage

Storage (acre-feet) 1514131211109876543210

Surface/Horizontal/Wetted Area (acres) 43210

E le va ti t)

1,220

1,219

1,218

1,217

1,216

1,215

Starting Elevation

Custom Stage Data

Summary for Pond 3P: Gravel Pit

Inflow Area = 43.200 ac, 0.00% Impervious, Inflow Depth = 2.11" for 5-Year event Inflow = 85.61 cfs @ 12.40 hrs, Volume= 7.609 af Outflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Atten= 100%, Lag= 0.0 min

Routing by Stor-Ind method, Time Span= 5.00-96.00 hrs, dt= 0.05 hrs Peak Elev= 1,215.09' @ 25.65 hrs Surf.Area= 7.010 ac Storage= 7.609 af

Plug-Flow detention time= (not calculated: initial storage exceeds outflow) Center-of-Mass det. time= (not calculated: no outflow)

Volume Invert Avail.Storage Storage Description #1 1,214.00' 28.755 af Custom Stage Data (Prismatic) Listed below (Recalc)

Elevation Surf.Area Inc.Store Cum.Store (feet) (acres) (acre-feet) (acre-feet)

1,214.00 6.900 0.000 0.000 1,216.00 7.102 14.002 14.002 1,218.00 7.651 14.753 28.755

Pond 3P: Gravel Pit

Inflow

Hydrograph

Time (hours) 969492908886848280787674727068666462605856545250484644424038363432302826242220181614121086

Inflow Area=43.200 ac Peak Elev=1,215.09'

Storage=7.609 af

85.61 cfs

Pond 3P: Gravel Pit

Total

Stage-Discharge

Discharge (cfs)

E le va ti t)

1,218

1,217

1,216

1,215

1,214

Pond 3P: Gravel Pit

Surface Storage

Stage-Area-Storage

Storage (acre-feet) 2826242220181614121086420

Surface/Horizontal/Wetted Area (acres) 76543210

E le va ti t)

1,218

1,217

1,216

1,215

1,214 Custom Stage Data

MSE 24-hr 3 10-Year Rainfall=4.50"Thrills Hills HydroCad

Time span=5.00-96.00 hrs, dt=0.05 hrs, 1821 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN

Reach routing by Stor-Ind method - Pond routing by Stor-Ind method

Runoff Area=50.400 ac 0.00% Impervious Runoff Depth=2.73"Subcatchment 1S: Direct Watershed Flow Length=2,323' Tc=59.6 min CN=83 Runoff=80.07 cfs 11.447 af

Runoff Area=43.200 ac 0.00% Impervious Runoff Depth=2.73"Subcatchment 3S: Gravel Pit Watershed Flow Length=1,659' Tc=27.6 min CN=83 Runoff=110.28 cfs 9.812 af

Peak Elev=1,217.83' Storage=7.142 af Inflow=80.07 cfs 11.447 afPond 2P: Wetland Pool Outflow=59.84 cfs 11.447 af

Peak Elev=1,215.41' Storage=9.812 af Inflow=110.28 cfs 9.812 afPond 3P: Gravel Pit Outflow=0.00 cfs 0.000 af

Total Runoff Area = 93.600 ac Runoff Volume = 21.259 af Average Runoff Depth = 2.73"

Summary for Subcatchment 1S: Direct Watershed

Runoff = 80.07 cfs @ 12.81 hrs, Volume= 11.447 af, Depth= 2.73" Routed to Pond 2P : Wetland Pool

Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-96.00 hrs, dt= 0.05 hrs MSE 24-hr 3 10-Year Rainfall=4.50"

Area (ac) CN Description

* 50.400 83

50.400 100.00% Pervious Area

Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs)

11.2 100 0.0200 0.15 Sheet Flow, Cultivated: Residue>20% n= 0.170 P2= 3.00"

4.3 664 0.0828 2.59 Shallow Concentrated Flow, SR Steep

Cultivated Straight Rows Kv= 9.0 fps

21.0 507 0.0020 0.40 Shallow Concentrated Flow, SR Flat

Cultivated Straight Rows Kv= 9.0 fps

18.0 770 0.0104 0.71 Shallow Concentrated Flow, Pasture

Short Grass Pasture Kv= 7.0 fps

5.1 282 0.0106 0.93 Shallow Concentrated Flow, SR

Cultivated Straight Rows Kv= 9.0 fps

59.6 2,323 Total

Subcatchment 1S: Direct Watershed

Runoff

Hydrograph

Time (hours) 9590858075706560555045403530252015105

MSE 24-hr 3 10-Year Rainfall=4.50" Runoff Area=50.400 ac

Runoff Volume=11.447 af Runoff Depth=2.73" Flow Length=2,323'

Tc=59.6 min

80.07 cfs

Summary for Subcatchment 3S: Gravel Pit Watershed

Runoff = 110.28 cfs @ 12.39 hrs, Volume= 9.812 af, Depth= 2.73" Routed to Pond 3P : Gravel Pit

Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-96.00 hrs, dt= 0.05 hrs MSE 24-hr 3 10-Year Rainfall=4.50"

Area (ac) CN Description

* 43.200 83

43.200 100.00% Pervious Area

Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs)

13.4 100 0.0100 0.12 Sheet Flow, Grass: Short n= 0.150 P2= 3.00"

0.8 108 0.0185 2.19 Shallow Concentrated Flow, Unpaved

Unpaved Kv= 16.1 fps

3.2 365 0.0438 1.88 Shallow Concentrated Flow, SR

Cultivated Straight Rows Kv= 9.0 fps

1.7 173 0.0578 1.68 Shallow Concentrated Flow, Pasture

Short Grass Pasture Kv= 7.0 fps

5.2 543 0.0368 1.73 Shallow Concentrated Flow, SR

Cultivated Straight Rows Kv= 9.0 fps

3.3 370 0.0730 1.89 Shallow Concentrated Flow, Pasture

Subcatchment 3S: Gravel Pit Watershed

Runoff

Hydrograph

Time (hours) 9590858075706560555045403530252015105

MSE 24-hr 3 10-Year Rainfall=4.50" Runoff Area=43.200 ac

Runoff Volume=9.812 af Runoff Depth=2.73" Flow Length=1,659'

Tc=27.6 min

110.28 cfs

Summary for Pond 2P: Wetland Pool

Inflow Area = 50.400 ac, 0.00% Impervious, Inflow Depth = 2.73" for 10-Year event Inflow = 80.07 cfs @ 12.81 hrs, Volume= 11.447 af Outflow = 59.84 cfs @ 13.17 hrs, Volume= 11.447 af, Atten= 25%, Lag= 21.9 min Primary = 59.84 cfs @ 13.17 hrs, Volume= 11.447 af

Routing by Stor-Ind method, Time Span= 5.00-96.00 hrs, dt= 0.05 hrs Starting Elev= 1,217.00' Surf.Area= 3.493 ac Storage= 4.190 af Peak Elev= 1,217.83' @ 13.17 hrs Surf.Area= 3.629 ac Storage= 7.142 af (2.952 af above start)

Plug-Flow detention time= 216.3 min calculated for 7.257 af (63% of inflow) Center-of-Mass det. time= 60.9 min ( 907.3 - 846.4 )

Volume Invert Avail.Storage Storage Description #1 1,215.00' 15.437 af Custom Stage Data (Prismatic) Listed below (Recalc)

Elevation Surf.Area Inc.Store Cum.Store (feet) (acres) (acre-feet) (acre-feet)

Device Routing Invert Outlet Devices #1 Primary 1,208.00' 36.0" Round Culvert

L= 128.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 1,208.00' / 1,207.50' S= 0.0039 '/' Cc= 0.900 n= 0.013, Flow Area= 7.07 sf

#2 Device 1 1,217.00' 6.0' long x 0.5' breadth Broad-Crested Rectangular Weir X 4.00 Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32

Primary OutFlow Max=59.76 cfs @ 13.17 hrs HW=1,217.83' TW=1,210.00' (Fixed TW Elev= 1,210.00') 1=Culvert (Passes 59.76 cfs of 95.23 cfs potential flow)

2=Broad-Crested Rectangular Weir (Weir Controls 59.76 cfs @ 3.01 fps)

Pond 2P: Wetland Pool

Inflow Primary

Hydrograph

Time (hours) 9590858075706560555045403530252015105

Inflow Area=50.400 ac Peak Elev=1,217.83'

Storage=7.142 af

80.07 cfs

59.84 cfs

Pond 2P: Wetland Pool

Primary

Stage-Discharge

Discharge (cfs) 260240220200180160140120100806040200

E le va ti t)

1,220

1,219

1,218

1,217

1,216

1,215

Pond 2P: Wetland Pool

Surface Storage

Stage-Area-Storage

Storage (acre-feet) 1514131211109876543210

Surface/Horizontal/Wetted Area (acres) 43210

E le va ti t)

1,220

1,219

1,218

1,217

1,216

1,215

Summary for Pond 3P: Gravel Pit

Inflow Area = 43.200 ac, 0.00% Impervious, Inflow Depth = 2.73" for 10-Year event Inflow = 110.28 cfs @ 12.39 hrs, Volume= 9.812 af Outflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Atten= 100%, Lag= 0.0 min

Routing by Stor-Ind method, Time Span= 5.00-96.00 hrs, dt= 0.05 hrs Peak Elev= 1,215.41' @ 25.65 hrs Surf.Area= 7.042 ac Storage= 9.812 af

Plug-Flow detention time= (not calculated: initial storage exceeds outflow) Center-of-Mass det. time= (not calculated: no outflow)

Volume Invert Avail.Storage Storage Description #1 1,214.00' 28.755 af Custom Stage Data (Prismatic) Listed below (Recalc)

Elevation Surf.Area Inc.Store Cum.Store (feet) (acres) (acre-feet) (acre-feet)

1,214.00 6.900 0.000 0.000 1,216.00 7.102 14.002 14.002 1,218.00 7.651 14.753 28.755

Pond 3P: Gravel Pit

Inflow

Hydrograph

Time (hours) 9590858075706560555045403530252015105

Inflow Area=43.200 ac Peak Elev=1,215.41'

Storage=9.812 af

110.28 cfs

Pond 3P: Gravel Pit

Total

Stage-Discharge

Discharge (cfs)

E le va ti t)

1,218

1,217

1,216

1,215

1,214

Pond 3P: Gravel Pit

Surface Storage

Stage-Area-Storage

Storage (acre-feet) 2826242220181614121086420

Surface/Horizontal/Wetted Area (acres) 76543210

E le va ti t)

1,218

1,217

1,216

MSE 24-hr 3 25-Year Rainfall=5.70"Thrills Hills HydroCad

Time span=5.00-96.00 hrs, dt=0.05 hrs, 1821 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN

Reach routing by Stor-Ind method - Pond routing by Stor-Ind method

Runoff Area=50.400 ac 0.00% Impervious Runoff Depth=3.81"Subcatchment 1S: Direct Watershed Flow Length=2,323' Tc=59.6 min CN=83 Runoff=111.78 cfs 16.018 af

Runoff Area=43.200 ac 0.00% Impervious Runoff Depth=3.81"Subcatchment 3S: Gravel Pit Watershed Flow Length=1,659' Tc=27.6 min CN=83 Runoff=153.40 cfs 13.730 af

Peak Elev=1,218.06' Storage=7.988 af Inflow=111.78 cfs 16.018 afPond 2P: Wetland Pool Outflow=87.06 cfs 16.018 af

Peak Elev=1,215.96' Storage=13.730 af Inflow=153.40 cfs 13.730 afPond 3P: Gravel Pit Outflow=0.00 cfs 0.000 af

Total Runoff Area = 93.600 ac Runoff Volume = 29.748 af Average Runoff Depth = 3.81"

Summary for Subcatchment 1S: Direct Watershed

Runoff = 111.78 cfs @ 12.80 hrs, Volume= 16.018 af, Depth= 3.81" Routed to Pond 2P : Wetland Pool

Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-96.00 hrs, dt= 0.05 hrs MSE 24-hr 3 25-Year Rainfall=5.70"

Area (ac) CN Description

* 50.400 83

50.400 100.00% Pervious Area

Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs)

11.2 100 0.0200 0.15 Sheet Flow, Cultivated: Residue>20% n= 0.170 P2= 3.00"

4.3 664 0.0828 2.59 Shallow Concentrated Flow, SR Steep

Cultivated Straight Rows Kv= 9.0 fps

21.0 507 0.0020 0.40 Shallow Concentrated Flow, SR Flat

Cultivated Straight Rows Kv= 9.0 fps

18.0 770 0.0104 0.71 Shallow Concentrated Flow, Pasture

Short Grass Pasture Kv= 7.0 fps

5.1 282 0.0106 0.93 Shallow Concentrated Flow, SR

Cultivated Straight Rows Kv= 9.0 fps

59.6 2,323 Total

Subcatchment 1S: Direct Watershed

Runoff

Hydrograph

Time (hours) 9590858075706560555045403530252015105

MSE 24-hr 3 25-Year Rainfall=5.70" Runoff Area=50.400 ac

Runoff Volume=16.018 af Runoff Depth=3.81" Flow Length=2,323'

Tc=59.6 min

111.78 cfs

Summary for Subcatchment 3S: Gravel Pit Watershed

Runoff = 153.40 cfs @ 12.39 hrs, Volume= 13.730 af, Depth= 3.81" Routed to Pond 3P : Gravel Pit

Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-96.00 hrs, dt= 0.05 hrs MSE 24-hr 3 25-Year Rainfall=5.70"

Area (ac) CN Description

* 43.200 83

43.200 100.00% Pervious Area

Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs)

13.4 100 0.0100 0.12 Sheet Flow, Grass: Short n= 0.150 P2= 3.00"

0.8 108 0.0185 2.19 Shallow Concentrated Flow, Unpaved

Unpaved Kv= 16.1 fps

3.2 365 0.0438 1.88 Shallow Concentrated Flow, SR

Cultivated Straight Rows Kv= 9.0 fps

1.7 173 0.0578 1.68 Shallow Concentrated Flow, Pasture

Short Grass Pasture Kv= 7.0 fps

5.2 543 0.0368 1.73 Shallow Concentrated Flow, SR

Cultivated Straight Rows Kv= 9.0 fps

3.3 370 0.0730 1.89 Shallow Concentrated Flow, Pasture

Subcatchment 3S: Gravel Pit Watershed

Runoff

Hydrograph

Time (hours) 9590858075706560555045403530252015105

MSE 24-hr 3 25-Year Rainfall=5.70" Runoff Area=43.200 ac

Runoff Volume=13.730 af Runoff Depth=3.81" Flow Length=1,659'

Tc=27.6 min

153.40 cfs

Summary for Pond 2P: Wetland Pool

Inflow Area = 50.400 ac, 0.00% Impervious, Inflow Depth = 3.81" for 25-Year event Inflow = 111.78 cfs @ 12.80 hrs, Volume= 16.018 af Outflow = 87.06 cfs @ 13.13 hrs, Volume= 16.018 af, Atten= 22%, Lag= 19.8 min Primary = 87.06 cfs @ 13.13 hrs, Volume= 16.018 af

Routing by Stor-Ind method, Time Span= 5.00-96.00 hrs, dt= 0.05 hrs Starting Elev= 1,217.00' Surf.Area= 3.493 ac Storage= 4.190 af Peak Elev= 1,218.06' @ 13.13 hrs Surf.Area= 3.667 ac Storage= 7.988 af (3.797 af above start)

Plug-Flow detention time= 169.2 min calculated for 11.821 af (74% of inflow) Center-of-Mass det. time= 54.0 min ( 893.7 - 839.7 )

Volume Invert Avail.Storage Storage Description #1 1,215.00' 15.437 af Custom Stage Data (Prismatic) Listed below (Recalc)

Elevation Surf.Area Inc.Store Cum.Store (feet) (acres) (acre-feet) (acre-feet)

Device Routing Invert Outlet Devices #1 Primary 1,208.00' 36.0" Round Culvert

L= 128.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 1,208.00' / 1,207.50' S= 0.0039 '/' Cc= 0.900 n= 0.013, Flow Area= 7.07 sf

#2 Device 1 1,217.00' 6.0' long x 0.5' breadth Broad-Crested Rectangular Weir X 4.00 Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32

Primary OutFlow Max=86.96 cfs @ 13.13 hrs HW=1,218.06' TW=1,210.00' (Fixed TW Elev= 1,210.00') 1=Culvert (Passes 86.96 cfs of 96.63 cfs potential flow)

2=Broad-Crested Rectangular Weir (Weir Controls 86.96 cfs @ 3.42 fps)

Pond 2P: Wetland Pool

Inflow Primary

Hydrograph

Time (hours) 9590858075706560555045403530252015105

Inflow Area=50.400 ac Peak Elev=1,218.06'

Storage=7.988 af

111.78 cfs

87.06 cfs

Pond 2P: Wetland Pool

Primary

Stage-Discharge

Discharge (cfs) 260240220200180160140120100806040200

E le va ti t)

1,220

1,219

1,218

1,217

1,216

1,215

Pond 2P: Wetland Pool

Surface Storage

Stage-Area-Storage

Storage (acre-feet) 1514131211109876543210

Surface/Horizontal/Wetted Area (acres) 43210

E le va ti t)

1,220

1,219

1,218

1,217

1,216

1,215

Summary for Pond 3P: Gravel Pit

Inflow Area = 43.200 ac, 0.00% Impervious, Inflow Depth = 3.81" for 25-Year event Inflow = 153.40 cfs @ 12.39 hrs, Volume= 13.730 af Outflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Atten= 100%, Lag= 0.0 min

Routing by Stor-Ind method, Time Span= 5.00-96.00 hrs, dt= 0.05 hrs Peak Elev= 1,215.96' @ 25.65 hrs Surf.Area= 7.098 ac Storage= 13.730 af

Plug-Flow detention time= (not calculated: initial storage exceeds outflow) Center-of-Mass det. time= (not calculated: no outflow)

Volume Invert Avail.Storage Storage Description #1 1,214.00' 28.755 af Custom Stage Data (Prismatic) Listed below (Recalc)

Elevation Surf.Area Inc.Store Cum.Store (feet) (acres) (acre-feet) (acre-feet)

1,214.00 6.900 0.000 0.000 1,216.00 7.102 14.002 14.002 1,218.00 7.651 14.753 28.755

Pond 3P: Gravel Pit

Inflow

Hydrograph

Time (hours) 9590858075706560555045403530252015105

Inflow Area=43.200 ac Peak Elev=1,215.96'

Storage=13.730 af

153.40 cfs

Pond 3P: Gravel Pit

Total

Stage-Discharge

Discharge (cfs)

E le va ti t)

1,218

1,217

1,216

1,215

1,214

Pond 3P: Gravel Pit

Surface Storage

Stage-Area-Storage

Storage (acre-feet) 2826242220181614121086420

Surface/Horizontal/Wetted Area (acres) 76543210

E le va ti t)

1,218

1,217

1,216

MSE 24-hr 3 100-Year Rainfall=7.90"Thrills Hills HydroCad

Time span=5.00-96.00 hrs, dt=0.05 hrs, 1821 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN

Reach routing by Stor-Ind method - Pond routing by Stor-Ind method

Runoff Area=50.400 ac 0.00% Impervious Runoff Depth=5.88"Subcatchment 1S: Direct Watershed Flow Length=2,323' Tc=59.6 min CN=83 Runoff=170.73 cfs 24.704 af

Runoff Area=43.200 ac 0.00% Impervious Runoff Depth=5.88"Subcatchment 3S: Gravel Pit Watershed Flow Length=1,659' Tc=27.6 min CN=83 Runoff=233.26 cfs 21.175 af

Peak Elev=1,218.72' Storage=10.436 af Inflow=170.73 cfs 24.704 afPond 2P: Wetland Pool Outflow=108.89 cfs 24.704 af

Peak Elev=1,216.99' Storage=21.175 af Inflow=233.26 cfs 21.175 afPond 3P: Gravel Pit Outflow=0.00 cfs 0.000 af

Total Runoff Area = 93.600 ac Runoff Volume = 45.879 af Average Runoff Depth = 5.88"

Summary for Subcatchment 1S: Direct Watershed

Runoff = 170.73 cfs @ 12.79 hrs, Volume= 24.704 af, Depth= 5.88" Routed to Pond 2P : Wetland Pool

Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-96.00 hrs, dt= 0.05 hrs MSE 24-hr 3 100-Year Rainfall=7.90"

Area (ac) CN Description

* 50.400 83

50.400 100.00% Pervious Area

Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs)

11.2 100 0.0200 0.15 Sheet Flow, Cultivated: Residue>20% n= 0.170 P2= 3.00"

4.3 664 0.0828 2.59 Shallow Concentrated Flow, SR Steep

Cultivated Straight Rows Kv= 9.0 fps

21.0 507 0.0020 0.40 Shallow Concentrated Flow, SR Flat

Cultivated Straight Rows Kv= 9.0 fps

18.0 770 0.0104 0.71 Shallow Concentrated Flow, Pasture

Short Grass Pasture Kv= 7.0 fps

5.1 282 0.0106 0.93 Shallow Concentrated Flow, SR

Cultivated Straight Rows Kv= 9.0 fps

59.6 2,323 Total

Subcatchment 1S: Direct Watershed

Runoff

Hydrograph

Time (hours) 9590858075706560555045403530252015105

MSE 24-hr 3 100-Year Rainfall=7.90" Runoff Area=50.400 ac

Runoff Volume=24.704 af Runoff Depth=5.88" Flow Length=2,323'

Tc=59.6 min

170.73 cfs

Summary for Subcatchment 3S: Gravel Pit Watershed

Runoff = 233.26 cfs @ 12.38 hrs, Volume= 21.175 af, Depth= 5.88" Routed to Pond 3P : Gravel Pit

Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 5.00-96.00 hrs, dt= 0.05 hrs MSE 24-hr 3 100-Year Rainfall=7.90"

Area (ac) CN Description

* 43.200 83

43.200 100.00% Pervious Area

Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs)

13.4 100 0.0100 0.12 Sheet Flow, Grass: Short n= 0.150 P2= 3.00"

0.8 108 0.0185 2.19 Shallow Concentrated Flow, Unpaved

Unpaved Kv= 16.1 fps

3.2 365 0.0438 1.88 Shallow Concentrated Flow, SR

Cultivated Straight Rows Kv= 9.0 fps

1.7 173 0.0578 1.68 Shallow Concentrated Flow, Pasture

Short Grass Pasture Kv= 7.0 fps

5.2 543 0.0368 1.73 Shallow Concentrated Flow, SR

Cultivated Straight Rows Kv= 9.0 fps

3.3 370 0.0730 1.89 Shallow Concentrated Flow, Pasture

Subcatchment 3S: Gravel Pit Watershed

Runoff

Hydrograph

Time (hours) 9590858075706560555045403530252015105

MSE 24-hr 3 100-Year Rainfall=7.90" Runoff Area=43.200 ac

Runoff Volume=21.175 af Runoff Depth=5.88" Flow Length=1,659'

Tc=27.6 min

233.26 cfs

Summary for Pond 2P: Wetland Pool

Inflow Area = 50.400 ac, 0.00% Impervious, Inflow Depth = 5.88" for 100-Year event Inflow = 170.73 cfs @ 12.79 hrs, Volume= 24.704 af Outflow = 108.89 cfs @ 13.26 hrs, Volume= 24.704 af, Atten= 36%, Lag= 28.0 min Primary = 108.89 cfs @ 13.26 hrs, Volume= 24.704 af

Routing by Stor-Ind method, Time Span= 5.00-96.00 hrs, dt= 0.05 hrs Starting Elev= 1,217.00' Surf.Area= 3.493 ac Storage= 4.190 af Peak Elev= 1,218.72' @ 13.26 hrs Surf.Area= 3.786 ac Storage= 10.436 af (6.246 af above start)

Plug-Flow detention time= 136.4 min calculated for 20.503 af (83% of inflow) Center-of-Mass det. time= 50.9 min ( 882.0 - 831.1 )

Volume Invert Avail.Storage Storage Description #1 1,215.00' 15.437 af Custom Stage Data (Prismatic) Listed below (Recalc)

Elevation Surf.Area Inc.Store Cum.Store (feet) (acres) (acre-feet) (acre-feet)

Device Routing Invert Outlet Devices #1 Primary 1,208.00' 36.0" Round Culvert

L= 128.0' RCP, square edge headwall, Ke= 0.500 Inlet / Outlet Invert= 1,208.00' / 1,207.50' S= 0.0039 '/' Cc= 0.900 n= 0.013, Flow Area= 7.07 sf

#2 Device 1 1,217.00' 6.0' long x 0.5' breadth Broad-Crested Rectangular Weir X 4.00 Head (feet) 0.20 0.40 0.60 0.80 1.00 Coef. (English) 2.80 2.92 3.08 3.30 3.32

Primary OutFlow Max=108.81 cfs @ 13.26 hrs HW=1,218.72' TW=1,210.00' (Fixed TW Elev= 1,210.00') 1=Culvert (Inlet Controls 100.49 cfs @ 14.22 fps)

2=Broad-Crested Rectangular Weir (Passes 100.49 cfs of 179.39 cfs potential flow) 3=Broad-Crested Rectangular Weir (Weir Controls 8.32 cfs @ 1.25 fps)

Pond 2P: Wetland Pool

Inflow Primary

Hydrograph

Time (hours) 9590858075706560555045403530252015105

Inflow Area=50.400 ac Peak Elev=1,218.72'

Storage=10.436 af

170.73 cfs

108.89 cfs

Pond 2P: Wetland Pool

Primary

Stage-Discharge

Discharge (cfs) 260240220200180160140120100806040200

E le va ti t)

1,220

1,219

1,218

1,217

1,216

1,215

Pond 2P: Wetland Pool

Surface Storage

Stage-Area-Storage

Storage (acre-feet) 1514131211109876543210

Surface/Horizontal/Wetted Area (acres) 43210

E le va ti t)

1,220

1,219

1,218

1,217

1,216

1,215

Summary for Pond 3P: Gravel Pit

Inflow Area = 43.200 ac, 0.00% Impervious, Inflow Depth = 5.88" for 100-Year event Inflow = 233.26 cfs @ 12.38 hrs, Volume= 21.175 af Outflow = 0.00 cfs @ 5.00 hrs, Volume= 0.000 af, Atten= 100%, Lag= 0.0 min

Routing by Stor-Ind method, Time Span= 5.00-96.00 hrs, dt= 0.05 hrs Peak Elev= 1,216.99' @ 25.65 hrs Surf.Area= 7.374 ac Storage= 21.175 af

Plug-Flow detention time= (not calculated: initial storage exceeds outflow) Center-of-Mass det. time= (not calculated: no outflow)

Volume Invert Avail.Storage Storage Description #1 1,214.00' 28.755 af Custom Stage Data (Prismatic) Listed below (Recalc)

Elevation Surf.Area Inc.Store Cum.Store (feet) (acres) (acre-feet) (acre-feet)

1,214.00 6.900 0.000 0.000 1,216.00 7.102 14.002 14.002 1,218.00 7.651 14.753 28.755

Pond 3P: Gravel Pit

Inflow

Hydrograph

Time (hours) 9590858075706560555045403530252015105

Inflow Area=43.200 ac Peak Elev=1,216.99'

Storage=21.175 af

233.26 cfs

Pond 3P: Gravel Pit

Total

Stage-Discharge

Discharge (cfs)

E le va ti t)

1,218

1,217

1,216

1,215

1,214

Pond 3P: Gravel Pit

Surface Storage

Stage-Area-Storage

Storage (acre-feet) 2826242220181614121086420

Surface/Horizontal/Wetted Area (acres) 76543210

E le va ti t)

1,218

1,217

1,216

Table of ContentsThrills Hills HydroCad

TABLE OF CONTENTS

Project Reports 1 Routing Diagram 2 Rainfall Events Listing 3 Area Listing (all nodes)

5-Year Event 4 Node Listing 5 Subcat 1S: Direct Watershed 6 Subcat 3S: Gravel Pit Watershed 8 Pond 2P: Wetland Pool 11 Pond 3P: Gravel Pit

10-Year Event 13 Node Listing 14 Subcat 1S: Direct Watershed 15 Subcat 3S: Gravel Pit Watershed 17 Pond 2P: Wetland Pool 20 Pond 3P: Gravel Pit

25-Year Event 22 Node Listing 23 Subcat 1S: Direct Watershed 24 Subcat 3S: Gravel Pit Watershed 26 Pond 2P: Wetland Pool 29 Pond 3P: Gravel Pit

100-Year Event 31 Node Listing 32 Subcat 1S: Direct Watershed 33 Subcat 3S: Gravel Pit Watershed 35 Pond 2P: Wetland Pool 38 Pond 3P: Gravel Pit

Page: 8

Appendix E: Pump Curve and Sump Design

1207.00

330 gpm

330 gal

44.1 cu. ft.

3.6 ft

1207.5

1203.5

22 in

1201.5

Minimum Working Volume

Pump Flow Rate

Pump Manufacturer Minimum Submergence

Inlet Pipe Elev.

Pump Basin Sizing Calculations

Bottom of Sump Elev.

Off Float Elev.

On Float Elev.

Minimum Working Sump Depth

Minimum Working Volume

Page: 9

Appendix F: Pipe Capacity Calculations

Description Dia (in) A (sf) P (ft) Rh (ft) s (%) n Qmax (cfs)

Pumped Inlet Pipe 18.00 1.77 4.71 0.38 1.30% 0.013 11.98

Existing Pond Outlet 6.00 0.20 1.57 0.13 1.36% 0.020 0.43

Proposed Pond Outlet Re-lay 8.00 0.35 2.09 0.17 0.98% 0.012 1.30

Wetland Outlet Pipe 36.00 7.07 9.42 0.75 0.39% 0.013 41.65

Pipe Capacity Calculations

File details come from the government source that posted it. Updated Oct 12, 2026.