E - H&H Report.pdf

H:\IDALS\24X135549000\3_Design\C_Reports\For Design Report\D Petersburg Wetland Design Report.docx

August 4, 2026

D. Petersburg Wetland Design Report Site No. WOR982210D Worth County, Iowa

Project Overview This constructed wetland is planned to provide nutrient reduction benefits to a part of the watershed of Winans Creek in Worth 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 Doug Petersburg between Joice and Hanlontown, Iowa. Three separate wetland pools will be created through a combination of excavation and the construction of embankments around the pool. Water from Winans Creek will be pumped into the east wetland to fill the pool. The northwest and southwest pools will be filled by water being pumped out of the existing Drainage District 23 Lateral 9 Tile and adjacent relief tile. Diversion berms are proposed within each wetland pool to encourage mixing and reduce short-circuiting of water out of the wetland.

Water will be released from the pools through rectangular wetland outlet structures and be carried through reinforced concrete pipes, discharging into Winans Creek. During large storm events, the pool levels will rise, and water will flow over earthen auxiliary spillways that direct the outflow to the creek.

Construction of the wetland will not have adverse effects on the hydrology of the neighboring properties.

Site Selection & Analysis This site was deemed viable because of the size of the creek’s watershed (9792 acres) and the area drained by DD 23 lateral 9 (2348 ac), along with the site’s topography.

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

Multiple soil borings were conducted across the site, the results of which can be found in the attached geotechnical report. A slope stability analysis was completed by Chosen Valley Testing (CVT) since this project proposes to construct a wetland above ditch banks that are steep and high. The analysis shows that the banks will be stable under the proposed conditions, as the short-term and long-term factors of safety are greater than 1.2, the minimum safety factor desired for slopes not near structures or not where they may pose a threat to human life.

The surface watersheds of the pools were delineated and analyzed. The Winans Creek watershed was not analyzed because runoff from that watershed will not be routed through the wetlands or impacted by the wetlands. Watershed information, curve number calculations, and runoff analysis are provided in the attached hydrology outputs.

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

Name: D. Petersburg Wetland Design Report Date: August 4, 2026 Page: 2 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, Constructed Wetland, dated December 2023, was used to develop this project. CPS 587 (Structure for Water Control) was used for the water control structure, and CPS 378 (Pond) was used to design the primary and auxiliary spillways and the embankment. The project is NRCS Job Class III under CPS 656 because the area of the direct watersheds total less than 300 acres.

Project Layout Permanent pool elevations and embankment locations were selected based on the ability to maximize pool area while minimizing the deep (greater than three feet) pool area and embankment height. 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 primary outlet structures and auxiliary spillways for the wetland. Exceeding the minimum design standards of NRCS CPS 378, the auxiliary spillway is placed above the 25-year storm, and the spillways and embankments are designed to provide at least one foot of freeboard during the 100-year storm. HydroCAD outputs are provided in the appendix.

Existing Tiles Two known tiles (DD Lateral 9 and the DD Lateral 9 relief line) are planned to be re-laid into a pump basin that will pump water to the northwest and southwest pools. From the pump basin, a new tile line will be constructed with a capacity greater than the capacity of the two tiles it is replacing. Pipe sizing calculations are provided for this pipe 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. The proposed dams of this project do not require a dam construction permit because the heights range from 4 to 4.5 feet, and the storage at the top of the dams range from 5.6 to 17.5 acre-feet. The hazard potential for the dams is low. The thresholds requiring a water storage permit are the same as those requiring a dam construction permit. Therefore, a water storage permit is not required.

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. The proposed dams meet the requirements of a low hazard dam.

Land Rights & Permits The permanent easement for this project will be on the Petersburg property. 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.

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The Army Corps of Engineers has indicated that no permit will be required for this project. A floodplain permit will also be obtained by IDALS if necessary; there is no established floodway at this location.

This project is located in Drainage District 23 in Fertile Township. Plans for the project will be provided to the drainage district for review and approval prior to the bidding of the project.

Sincerely, Bolton & Menk, Inc.

Brandon C. Short, PE Water Resources Project Engineer

Appendices:

A. Soil Survey Map B. Pump Basin Sizing Calculations C. Pipe Capacity Calculations D. Watershed Map E. Hydrology Report F. Geotechnical Report G. HydroCAD Output

Page: 4

Appendix A: Soil Survey Map

Page: 5

Appendix B: Pump Basin Sizing Calculations

Criteria Provided Requirement Inlet Pipe Elev. 1183.00

Pump Flow Rate 295 gpm Working Volume (Minimum) 306 gal 295 gal Working Volume (Minimum) 40.8 cu. ft. 39.4 cu. ft.

Working Sump Depth (Minimum) 3.3 ft 3.1 ft On Float Elev. 1183.5 Off Float Elev. 1180.25

Pump Submergence (Minimum) 31 in 30 in Bottom of Sump Elev. (Max.) 1177.7 1177.75

East Pump Basin Sizing Calculations

Criteria Provided Requirement Inlet Pipe Elev. 1185.72

Pump Flow Rate 380 gpm Working Volume (Minimum) 411 gal 380 gal Working Volume (Minimum) 55.0 cu. ft. 50.8 cu. ft.

Working Sump Depth (Minimum) 2.8 ft 2.5 ft On Float Elev. 1185.5 Off Float Elev. 1182.75

Pump Submergence (Minimum) 21.0 in 20.5 in Bottom of Sump Elev. (Max.) 1181 1181.04

West Pump Basin Sizing Calculations

Page: 6

Appendix C: Pipe Capacity Calculations

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

Existing DD 23 Lat. 9 24.00 3.142 6.283 0.500 2.14% 0.012 35.85

Proposed DD 23 Lat. 9 Re-lay 24.00 3.142 6.283 0.500 9.01% 0.013 67.90

Existing DD 23 Relief Tile 30.00 4.909 7.854 0.625 0.67% 0.013 33.57

Proposed DD 23 Relief Tile Re-lay 36.00 7.069 9.425 0.750 0.50% 0.013 47.16

Existing Culvert 18.00 1.767 4.712 0.375 7.87% 0.027 14.19

Proposed Culvert 18.00 1.767 4.712 0.375 7.87% 0.027 14.19

East Pool Outlet Pipe 18.00 1.767 4.712 0.375 2.00% 0.013 14.86

Northwest Pool Outlet Pipe 30.00 4.909 7.854 0.625 2.00% 0.013 58.01

Southwest Pool Outlet Pipe 12.00 0.785 3.142 0.250 2.00% 0.013 5.04

Pipe Capacity Calculations

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Appendix D: Watershed Map

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Appendix E: Hydrology Report

Hydrology Analysis Summary 25-year Event: 5.80'' 100-year Event: 7.80''

* Hydrologic Soil Groups: B, C, D

* Runoff Curve Number: 82.3 (based on Land use shown in this report)

* Primary Spillway Weir Coefficent = 3.1

* Tc = 82.3 as determined by the sum of sheet and shallow concentrated flow times.

* Normal pool areas range from 1.66 to 4.51 acres.

* Surface watershed area is approx. 64.83 acres or 0.1 square miles.

Design Parameters and Procedures:

Report Summary

Design hydrology and hydraulic study of this site was completed. The drainage areas were determined and stage-area-storage curves were developed based on the topographic survey, LiDAR data, and grading design for the wetlands. Land use and treatment were determined through aerial photo review. Hydrologic data was compiled, the structures were flood routed using TR-55 in the HydroCAD Software, and all the output was reviewed.

Rainfall events used for this site were MSE 3 distribution, 24-hour, 5-, 10-, 25-, and 100-year events. The primary spillways are rectangular open-sided intake structures which discharge through a pipe to the ditch. The secondary spillways are earthen auxiliary spillways in the earthen berms.

Summary Table: East Pool Normal Pool Elevation: 1196.50

Qmax In (cfs)

Qmax Out (cfs)

Max Elev (ft)

5-year 50.33 4.63 1197.01 10-year 61.33 6.19 1197.07 25-year 79.74 9.99 1197.19

100-year 109.86 18.35 1197.36

Summary Table: Northwest Pool Normal Pool Elevation: 1196.50

Qmax In (cfs)

Qmax Out (cfs)

Max Elev (ft)

5-year 68.40 44.91 1197.30 10-year 86.54 58.93 1197.47

25-year 118.00 71.62 1197.83 100-year 169.76 108.80 1198.42

Summary Table: Southwest Pool Normal Pool Elevation: 1198

Qmax In (cfs)

Qmax Out (cfs)

Max Elev (ft)

5-year 19.35 4.51 1198.24 10-year 23.37 5.86 1198.28

25-year 30.21 8.29 1198.36 100-year 41.50 10.09 1198.49

H:\IDALS\24X135549000\3_Design\C_Reports\Doug Petersburg Hydrology Report.xlsm

IDALS ID Number: WOR982210D Job: D. Petersburg

BMI Project Number: 24X.135549.000 Designed By: BCS Date: 8/4/2026

Rainfall Data

Frequency yr in 1 in 2 in 3

2 3.06 3.06 3.10

5 3.86 3.83 3.90

10 4.61 4.55 4.60

25 5.78 5.67 5.80

50 6.80 6.63 6.80

100 7.90 7.68 7.80

References

1 NOAA Atlas 14, Volume 8, Version 2 2 SUDAS Design 2022 Edition 3 24-hour rainfall depths by county from NEH Title 210 (Figure IA2-25)

24-hr Rainfall Depth

Surface-Drained DA = 65 ac

Box indicates greater value and was selected.

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

= .1 sq mi

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BMI Project Number: 24X.135549.000 Designed By: BCS Date: 8/4/2026

Tributary Watershed Data

Watershed Area (ac) Area (sq. mi.) Surface/Pump Flow

Direct - Northwest Pool 36.5 0.06 Surface

Direct - Southwest Pool 3.5 0.01 Surface

Direct - East Pool 24.8 0.04 Surface

1 DD 23 Lat. 9 2349 3.67 Pump

2 Winans Creek 9792 15.30 Pump

Surface Total 65 0.10

Pumped (Treated) Total 12141 18.97

Notes 1 Tile pumped to Northwest and Southwest Pools.

2 Drainage ditch pumped to East Pool.

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BMI Project Number: 24X.135549.000 Designed By: BCS Date: 8/4/2026

Typical Cover Portion Soil Name1 HSG1 Type of W/S CN2 Product percent

Hawick Sandy Loam A Straight Row Crops, Good 3.3% 67 2.2

Clarion-Storden Complex et al. B, B/D Straight Row Crops, Good 30.0% 78 23.4

Clarion Loam, Marshan Clay Loam et al. C, C/D Straight Row Crops, Good 66.7% 85 56.7

Total 100.0% 82.3

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

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

Note: This soil information is a summary of the data for the surface watersheds of the three wetland pools, which watersheds were used to model the storm responses in the three pools. Representative soil types are shown. Actual curve number calculations used for the modeling is provided in the HydroCAD outputs.

= .1 sq mi Runoff Curve Number Surface-Drained DA = 65 ac

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BMI Project Number: 24X.135549.000 Designed By: BCS Date: 8/4/2026

Stage-Storage - East Pool

Contour Elev. Area Area

Average Area

Incremental Volume

Cumulative Volume

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

1194.50 17700 0.41 0.41 0.00 0.00

1195.00 62200 1.43 0.92 0.46 0.46

1195.50 114900 2.64 2.03 1.02 1.47

1196.00 160400 3.68 3.16 1.58 3.05

1196.50 196500 4.51 4.10 2.05 5.10

1197.00 233000 5.35 4.93 2.46 7.57

1197.50 269400 6.18 5.77 2.88 10.45

1198.00 304700 6.99 6.59 3.29 13.75

1198.50 337700 7.75 7.37 3.69 17.43

Storage at Normal Pool 5.10 Acre-feet storage at normal pool

Elevation of weir = 1196.50 area at normal pool

Storage at Overflow 7.57 Acre-feet

1197.00 1.13 feet

Notes:

Elevation =

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

= .1 sq mi Surface-Drained DA = 65 ac

Average Depth =

Average Depth =

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BMI Project Number: 24X.135549.000 Designed By: BCS Date: 8/4/2026

Stage-Storage - Northwest Pool

Contour Elev. Area Area

Average Area

Incremental Volume

Cumulative Volume

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

1196.00 77100 1.77 1.77 0.00 0.00

1196.50 80400 1.85 1.81 0.90 0.90

1197.00 87700 2.01 1.93 0.96 1.87

1197.50 95850 2.20 2.11 1.05 2.92

1198.00 104000 2.39 2.29 1.15 4.07

1199.00 114600 2.63 2.51 2.51 6.58

Storage at Normal Pool 0.90 Acre-feet storage at normal pool

Elevation of weir = 1196.50 area at normal pool

Storage at Overflow 2.92 Acre-feet

1197.50 0.49 feet

Notes:

Average Depth =

Elevation = Average Depth =

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

Surface-Drained DA = 65 ac

= .1 sq mi

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BMI Project Number: 24X.135549.000 Designed By: BCS Date: 8/4/2026

Stage-Storage - Southwest Pool

Contour Elev. Area Area

Average Area

Incremental Volume

Cumulative Volume

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

1195.00 500 0.01 0.01 0.00 0.00

1196.00 9600 0.22 0.12 0.12 0.12

1197.00 24600 0.56 0.39 0.39 0.51

1198.00 72500 1.66 1.11 1.11 1.62

1198.50 77700 1.78 1.72 0.86 2.49

1199.00 82900 1.90 1.84 0.92 3.41

1200.00 107900 2.48 2.19 2.19 5.60

Storage at Normal Pool 1.62 Acre-feet storage at normal pool

Elevation of weir = 1198.00 area at normal pool

Storage at Overflow 2.49 Acre-feet

1198.50 0.98 feet

Notes:

Surface-Drained DA = 65 ac

= .1 sq mi

Average Depth =

Elevation = Average Depth =

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

H:\IDALS\24X135549000\3_Design\C_Reports\Doug Petersburg Hydrology Report.xlsm Page 7

BMI Project Number: 24X.135549.000 Designed By: BCS Date: 8/4/2026

Wetland Pool

Pump Outlet

Dia. (in) TDH (ft)

Peak Pumping Rate

(gpm)

Peak Pumping Rate (cfs)

9-Month Percent Capture1

Watershed Area (ac)2

Effective Pumped

Watershed (ac) East 3.0 HP 6 15.60 290 0.65 11.2% 9792 1097

Northwest 1.5 HP 6 13.65 200 0.45 21.0% 2349 493 Southwest 1.5 HP 6 15.65 180 0.40 21.2% 2349 498

Notes:

Pump Summary

Solar Pump Capture Calculations

1 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.

Average Daylight Hours: 54.4%

2 Provided by StreamStats

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BMI Project Number: 24X.135549.000 Designed By: BCS Date: 8/4/2026

Results - East Pool

1194.50 0.40 0.00 0.00 0.00

1195.00 1.40 0.00 0.00 0.00

1195.50 2.60 0.00 0.00 0.00

1196.00 3.70 0.00 0.00 0.00

1196.50 4.50 0.00 0.00 0.00

1197.00 5.30 4.51 0.00 4.51

1197.50 6.20 12.43 14.42 26.85

1198.00 7.00 22.23 50.46 72.69

1198.50 7.80 23.69 102.47 126.16

= .04 sq miSurface-Drained DA = 24.8 ac

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.

Primary Outlet

Aux.

Spillway Total Discharge (cfs)Elevation

Pool Area (ac)

0.0025.0050.0075.00100.00125.00

1194.5

1195.5

1196.5

1197.5

1198.5

0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00

Discharge (cfs)

E le va ti o n

Pool Area (ac)

Pool Area-Elevation-Discharge Graph

Normal Pool

Pool Area (ac)

Discharge (cfs)

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BMI Project Number: 24X.135549.000 Designed By: BCS Date: 8/4/2026

Results - Northwest Pool

1196.00 1.80 0.00 0.00 0.00

1196.50 1.90 0.00 0.00 0.00

1197.00 2.00 22.66 0.00 22.66

1198.00 2.60 61.41 20.62 82.03

1199.00 3.10 65.80 120.05 185.85

Surface-Drained DA = 36.5 ac = .06 sq mi

The Elevation-Discharge table below shows tile and surface outflows from the wetland for various elevations. The tile discharge is very small compared to the surface discharge at higher elevations.

Elevation Pool Area

(ac) Primary Outlet Aux. Spillway

Total Discharge (cfs)

0.0040.0080.00120.00160.00200.00

1195.5

1196.5

1197.5

1198.5

1199.5

1.75 1.95 2.15 2.35 2.55 2.75

Discharge (cfs)

E le va ti o n

Pool Area (ac)

Pool Area-Elevation-Discharge Graph

Normal Pool

Series1

Series2

H:\IDALS\24X135549000\3_Design\C_Reports\Doug Petersburg Hydrology Report.xlsm Page 10

BMI Project Number: 24X.135549.000 Designed By: BCS Date: 8/4/2026

Results - Southwest Pool

1195.00 0.10 0.00 0.00

1196.00 0.22 0.00 0.00

1197.00 0.56 0.00 0.00

1198.00 1.66 0.00 0.00

1199.00 1.90 10.38 20.62 31.00

1200.00 2.48 10.93 120.05 130.98

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) Primary Outlet

Aux.

Spillway

Total Discharge (cfs)

Surface-Drained DA = 3.5 ac = .01 sq mi

0.0030.0060.0090.00120.00150.00

0.00 0.50 1.00 1.50 2.00 2.50

Discharge (cfs)

E le va ti o n

Pool Area (ac)

Pool Area-Elevation-Discharge Graph

Normal Pool

Pool Area (ac)

Series2

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Page: 9

Appendix F: Geotechnical Report

IOWA MINNESOTA WISCONSIN

Updated Factual Geotechnical Report:

Proposed Wetland SE ¼ Sec. 10 – T98N – R22W Fertile Township, Worth County, Iowa

CVT# 24387.24.IAM

Prepared for:

Mr. Brandon Short Bolton & Menk, Inc.

Certification:

I hereby certify that this engineering document was prepared by me or under my direct personal supervision and that I am a duly licensed Professional Engineer under the laws of the State of Iowa.

April 21, 2025

(signature) (date)

Printed or typed name: Matthew J. Reisdorfer, PE.

License number: 22234 .

My license renewal date is December 31, 2025 .

Pages or sheets covered by this seal:

M i n n e s o t a I o w a W i s c o n s i n

TABLE OF CONTENTS

A. Introduction

A.1. Purpose

A.2. Scope

A.3. Boring Locations and Elevation

A.4. Geologic Background

B. Subsurface Data

B.1. Stratification

B.2. Penetration Test Results

B.3. Groundwater Data

F. Slope Stability Analysis

C. Level of Care

Appendix

Soil Boring Location Sketch

Log of Boring # B1-B10 and HA1-HA4

Slope Stability Cross Sections

Legend to Soil Description

Worth County Wetland November 25, 2024

Project: 24387.24.IAM Page - 2

Chosen Valley Testing, Inc.

Geotechnical Engineering and Testing • 421 N Georgia Avenue • Mason City, IA 50401 • Telephone (641) 201-1050 • masoncity@cvtesting.com

Mr. Brandon Short April 21, 2025

Design Engineer

Bolton & Menk, Inc.

1519 Baltimore Drive

Ames, Iowa 50010

Brandon.short@bolton-menk.com

Re: Factual Geotechnical Evaluation

SE ¼ Sec. 10 – T98N – R22W

Fertile Township, Worth County, Iowa

CVT Proposal Number: 24387.24.IAM

Dear Mr. Short:

This factual report was prepared for the proposed wetland located in Fertile Township, Worth County, Iowa.

Our services were authorized by Mr. Brandon Short, Design Engineer for Bolton & Menk, Inc.

A. Introduction

The intent of this report is to present our results to the client in the same logical sequence that led us to arrive at the opinions and recommendations expressed. Since our services must often be completed before the design, assumptions are sometimes needed to prepare a proper evaluation and to analyze the data. A complete and thorough review of this entire document, including the assumptions and the appendices, should be undertaken immediately upon receipt.

A.1. Purpose

This factual report was prepared for the proposed wetland located in Fertile Township, Worth County, Iowa.

Our services were authorized by Mr. Brandon Short, Design Engineer for Bolton & Menk, Inc.

A.2. Scope

To obtain data for analysis, our services included ten penetration test borings. The borings were drilled to depths of about 15 feet below the surface. Additional services consisting of hand auger drilling and slope stability analysis were also authorized. Our engineering scope consisted of providing a factual discussion of the soils and materials encountered during our exploration.

mailto:masoncity@cvtesting.com mailto:Brandon.short@bolton-menk.com

Project: 24387.24.IAM Page - 3

A.3. Boring Locations and Elevation

The desired boring locations were indicated to Chosen Valley Testing based on on-site staking provided by the client. The Boring Location Sketch in the Appendix shows the approximate location drilled. Elevations at the borings were provided by the client.

A.4. Geologic Background

A geotechnical report is based on subsurface data collected for the specific structure or problem. Available geologic data from the region can help interpretation of the data and is briefly summarized in this section.

Area geologic maps indicate that the natural upper soils are primarily alluvium (water deposited) consisting of clay, silt, sand and gravel mixtures. Bedrock was expected to be within 50 to 100 feet below the surface and consists of limestone, dolomite, and shale of the Shell Rock Formation.

B. Subsurface Data

B.1. Stratification

At the surface, the borings met topsoil consisting mostly of slightly organic-to-organic lean clay to depths of about 1 to 2 feet below the surface. Below the topsoil, Borings B-4, B-8, B-9 and B-10 met B-Horizon consisting of mostly lean clay and sandy clay to depths of about 4 to 6 ½ feet below the surface. B-Horizon soils are similar in color and characteristics to that of topsoil but are less organic.

Alluvial clay was met below the B-Horizon and below the topsoil in Borings B-1, B-2, B-3, B-5, B-6 and B-7 to depths of about 3 to 9 feet below the surface.

Alluvial sand and gravel followed the alluvial clay in all borings. The borings terminated in alluvial sand and gravel at depths of about 16 feet below the surface.

The following simplified cross-section summarizes the boring data. For more detailed information, please refer to the Log of Boring sheets in the Appendix.

Project: 24387.24.IAM Page - 4

B-1 B-2 B-3 B-4 B-5 B-6 B-7 B-8 B-9 B-10

A p p ro x im a te

E le v a ti o n o n t h e D a tu m U s e d F e e t)

Boring Number

Topsoil

B-Horizon

Alluvial Clay

Alluvial Sand and Gravel

Below Boring

North to South

B.2. Penetration Test Results

The number of blows needed for the hammer to advance the penetration test sampler is an indicator of soil characteristics. The results tend to be more meaningful for natural mineral soils, than for fill soils. In fill soils, compaction tests are more meaningful.

Penetration resistance values ("N" Values) of 2 to 13 Blows per Foot (BPF) were recorded in the alluvial clays, indicating they were soft to stiff. The alluvial sands returned N-Values of 3 to 34 BPF, indicating they were very loose to dense. The B-Horizon clays returned N-Values of 2 to 7 BPF, indicating they were soft to medium.

A pocket penetrometer was used to provide additional data on the compressive strength of cohesive soils. The alluvial clays returned values of 1 ¼ to 3 ¾ tons per square foot (tsf). The B-Horizon clays returned values of

1 ¼ to 4 ¼ tsf.

A key to descriptors used to qualify the relative density of soil (such as soft, stiff, loose, and dense) can be found on the Legend to Soil Description in the Appendix.

Project: 24387.24.IAM Page - 5

B.3. Groundwater Data

During the drilling operation, the drillers may note the presence of moisture on the sampling instrument, in the cuttings, or within the borehole. These observations are recorded on the boring logs. The water level may vary with weather; time of year and other factors and the presence or absence of water during the drilling is subject to interpretation and is not always conclusive.

Water was encountered in most of the borings at depths of about 7 to 14 feet below the surface during drilling.

The observed water levels correspond to an elevation of about 1180 ½ to 1188 feet on the datum used to locate the borings. Elevated moisture contents were recorded in the near surface clay samples as well. Groundwater levels at the site are expected to fluctuate seasonally with nearby creeks and rivers, as well as with local weather patterns.

F. Slope Stability Analysis

Slope stability analyses were performed along the drainage ditch embankment near STA 2+40, STA 9+10, STA 13+25 and STA 14+00 using the elevation data provided by Bolton & Menk, Inc. and the computer software Slide that employs both Janbu’s and Bishops’ Methods of Analysis. Data from our boring logs and hand auger exploration were used in our analysis. Design slopes ranging from 1.6:1 to 1.9:1 were provided by Bolton & Menk, Inc.

The following table provides further detail on the short term and long term stability safety factors at each of the four stations that were analyzed:

Station Short Term Stability Safety Factor

(West Bank/East Bank)

Long Term Stability Safety Factor

(West Bank/East Bank)

STA 2+40 1.973 / 1.556 1.568 / 1.227

STA 9+10 2.393 / 1.925 1.793 / 1.496

STA 13+25 3.089 / 2.157 2.982 / 1.994

STA 14+00 1.850 / 1.419 1.496 / 1.244

A minimum safety factor of 1.2 is normally desired for slopes not near structures or not where they may pose a threat to human life. All safety factors from our analysis exceeded the minimum safety factor.

It should be noted that exposed slopes will be prone to surface erosion and shallow failures. Therefore, we recommend protecting surfaces with vegetation or other erosion control methods.

C. Level of Care

The services provided for this project have been conducted in a manner consistent with that level of care and skill ordinarily exercised by members of the profession currently practicing in this area, under similar budget and time constraints. This is our professional responsibility. No other warranty, expressed or implied, is made.

Project: 24387.24.IAM Page - 6

Appendix

Soil Boring Location Sketch

Log of Boring: B1-B10 and HA1-HA4

Slope Stability Cross Sections

Legend to Soil Description

ORGANIC CLAY trace of roots, black, wet.

(Topsoil)

LEAN CLAY with SAND trace of gravel, trace of iron staining, light grey, wet, rather stiff.

(Alluvium)

POORLY-GRADED SAND to CLAYEY SAND mostly medium grained, trace of gravel, trace of iron staining, brown, moist, medium dense.

(Alluvium)

POORLY-GRADED SAND mostly medium grained, trace of gravel, brown, moist, medium dense.

(Alluvium)

POORLY-GRADED GRAVEL with SAND mostly coarse grained, brown, moist, loose.

(Alluvium)

POORLY-GRADED SAND mostly medium grained, trace of gravel, grey, moist to waterbearing, loose.

(Alluvium)

End of boring.

Boring sealed upon completion.

OL

CL

SP

SC

SP

GP

SP

Elevations provided by Bolton & Menk, Inc.

MC = 38.1%

PP = 2.75 tsf

Water encountered at about 12 feet during drilling.

1.5

4.0

6.5

9.0

11.5

16.0

1195.1

1192.6

1190.1

1187.6

1185.1

1180.6

B-01 page 1 of 1

0.0

BORING: B-01

24387.24.IAM

Description of Materials

(ASTM D 2487/2488)

PROJECT:

1196.6

L O G O F B O R I N G

CHOSEN VALLEY TESTING

SCALE: 1" = 2'

BPF

24387.24.IAM

Factual Geotechnical Evaluation Proposed Wetland SE 1/4 Sec. 10 - T98N - R22W Fertile Township, Worth County, Iowa

See attached sketch

LOCATION:

WLUSCS

Symbol Tests and NotesDepthElev.

DATE: 11/6/2024

C V

T S

T A

N D

A R

D

.2 4.

IA

M

W

O R

T H

C O

U N

T Y

W E

T

LA

N D

G

P J

L O

G A

G N

N N

.G

D T

/2

8/

Slightly Organic LEAN CLAY trace of roots, black, wet.

(Topsoil) SANDY LEAN CLAY trace of gravel, trace of iron staining, light grey, wet, rather stiff.

(Alluvium)

CLAYEY SAND to SILTY SAND mostly fine grained, trace of gravel, light brown, moist, loose to medium dense.

(Alluvium)

POORLY-GRADED SAND mostly medium grained, trace of gravel, light brown to grey, moist to waterbearing, loose to medium dense.

(Alluvium)

Trace of clay below about 9 feet to about 11.5 feet.

End of boring.

Boring sealed upon completion.

CL

OL

CL

SC

SM

SP

Elevations provided by Bolton & Menk, Inc.

Water encountered at about 12 feet during drilling.

1.0

3.0

6.5

16.0

1198.4

1196.4

1192.9

1183.4

B-02 page 1 of 1

0.0

BORING: B-02

24387.24.IAM

Description of Materials

(ASTM D 2487/2488)

PROJECT:

1199.4

L O G O F B O R I N G

CHOSEN VALLEY TESTING

SCALE: 1" = 2'

BPF

24387.24.IAM

Factual Geotechnical Evaluation Proposed Wetland SE 1/4 Sec. 10 - T98N - R22W Fertile Township, Worth County, Iowa

See attached sketch

LOCATION:

WLUSCS

Symbol Tests and NotesDepthElev.

DATE: 11/6/2024

C V

T S

T A

N D

A R

D

.2 4.

IA

M

W

O R

T H

C O

U N

T Y

W E

T

LA

N D

G

P J

L O

G A

G N

N N

.G

D T

/2

(Topsoil)

SANDY LEAN CLAY trace of gravel, trace of iron staining, dark grey, wet, soft to rather soft.

(Alluvium)

POORLY-GRADED SAND mostly medium grained, trace of gravel, grey, waterbearing, very loose to loose.

(Alluvium)

POORLY-GRADED SAND to CLAYEY SAND mostly medium grained, trace of gravel, grey, waterbearing, loose.

(Alluvium)

POORLY-GRADED SAND with GRAVEL mostly coarse grained, brown, moist, loose.

(Alluvium)

End of boring.

Boring sealed upon completion.

CL

OL

CL

SP

SP

SC

SP

Elevations provided by Bolton & Menk, Inc.

PP = 1.75 tsf, MC = 29.9%

Water encountered at about 7 feet during drilling.

2.0

7.5

9.0

11.5

16.0

1193.0

1187.5

1186.0

1183.5

1179.0

B-03 page 1 of 1

0.0

BORING: B-03

24387.24.IAM

Description of Materials

(ASTM D 2487/2488)

PROJECT:

1195.0

L O G O F B O R I N G

CHOSEN VALLEY TESTING

SCALE: 1" = 2'

BPF

24387.24.IAM

Factual Geotechnical Evaluation Proposed Wetland SE 1/4 Sec. 10 - T98N - R22W Fertile Township, Worth County, Iowa

See attached sketch

LOCATION:

WLUSCS

Symbol Tests and NotesDepthElev.

DATE: 11/6/2024

C V

T S

T A

N D

A R

D

.2 4.

IA

M

W

O R

T H

C O

U N

T Y

W E

T

LA

N D

G

P J

L O

G A

G N

N N

.G

D T

/2

(Topsoil)

SANDY LEAN CLAY trace of gravel, black, wet, soft to medium.

(B-Horizon)

LEAN CLAY with SAND trace of iron staining, dark brown, wet, rather soft.

(Alluvium)

POORLY-GRADED SAND to CLAYEY SAND with GRAVEL mostly medium grained, grey, moist, loose.

(Alluvium)

POORLY-GRADED SAND mostly medium grained, trace of gravel, grey, moist, loose.

(Alluvium)

End of boring.

Boring sealed upon completion.

CL

OL

CL

CL

SP

SC

SP

Elevations provided by Bolton & Menk, Inc.

PP = 4.25 tsf, MC = 19.8%

PP = 3.0 tsf, MC = 25.4%

PP = 1.25 tsf

2.0

6.5

9.0

11.5

16.0

1195.7

1191.2

1188.7

1186.2

1181.7

B-04 page 1 of 1

0.0

BORING: B-04

24387.24.IAM

Description of Materials

(ASTM D 2487/2488)

PROJECT:

1197.7

L O G O F B O R I N G

CHOSEN VALLEY TESTING

SCALE: 1" = 2'

BPF

24387.24.IAM

Factual Geotechnical Evaluation Proposed Wetland SE 1/4 Sec. 10 - T98N - R22W Fertile Township, Worth County, Iowa

See attached sketch

LOCATION:

WLUSCS

Symbol Tests and NotesDepthElev.

DATE: 11/6/2024

C V

T S

T A

N D

A R

D

.2 4.

IA

M

W

O R

T H

C O

U N

T Y

W E

T

LA

N D

G

P J

L O

G A

G N

N N

.G

D T

/2

(Topsoil)

LEAN CLAY with SAND trace of gravel, trace of iron staining, dark brown to grey, wet, rather soft to medium.

(Alluvium)

POORLY-GRADED SAND mostly medium grained, trace of gravel, grey to brown, moist to waterbearing, loose to medium dense.

(Alluvium)

Trace of clay below about 11.5 feet to about 14 feet.

End of boring.

Boring sealed upon completion.

CL

OL

CL

SP

Elevations provided by Bolton & Menk, Inc.

MC = 44.2%

PP = 1.25 tsf, MC = 30.3%

Water encountered at about 10 feet during drilling.

2.0

6.5

16.0

1195.5

1191.0

1181.5

B-05 page 1 of 1

0.0

BORING: B-05

24387.24.IAM

Description of Materials

(ASTM D 2487/2488)

PROJECT:

1197.5

L O G O F B O R I N G

CHOSEN VALLEY TESTING

SCALE: 1" = 2'

BPF

24387.24.IAM

Factual Geotechnical Evaluation Proposed Wetland SE 1/4 Sec. 10 - T98N - R22W Fertile Township, Worth County, Iowa

See attached sketch

LOCATION:

WLUSCS

Symbol Tests and NotesDepthElev.

DATE: 11/6/2024

C V

T S

T A

N D

A R

D

.2 4.

IA

M

W

O R

T H

C O

U N

T Y

W E

T

LA

N D

G

P J

L O

G A

G N

N N

.G

D T

/2

(Topsoil)

SANDY LEAN CLAY trace of gravel, trace of iron staining, light grey, wet, rather stiff to stiff.

(Alluvium)

POORLY-GRADED SAND mostly medium to coarse grained, trace of gravel, light brown to grey, moist to waterbearing, loose to medium dense.

(Alluvium)

Trace of silt below about 14 feet.

End of boring.

Boring sealed upon completion.

CL

OL

CL

SP

Elevations provided by Bolton & Menk, Inc.

MC = 14.5%

Water encountered at about 10 feet during drilling.

2.0

5.5

16.0

1193.6

1190.1

1179.6

B-06 page 1 of 1

0.0

BORING: B-06

24387.24.IAM

Description of Materials

(ASTM D 2487/2488)

PROJECT:

1195.6

L O G O F B O R I N G

CHOSEN VALLEY TESTING

SCALE: 1" = 2'

BPF

24387.24.IAM

Factual Geotechnical Evaluation Proposed Wetland SE 1/4 Sec. 10 - T98N - R22W Fertile Township, Worth County, Iowa

See attached sketch

LOCATION:

WLUSCS

Symbol Tests and NotesDepthElev.

DATE: 11/4/2024

C V

T S

T A

N D

A R

D

.2 4.

IA

M

W

O R

T H

C O

U N

T Y

W E

T

LA

N D

G

P J

L O

G A

G N

N N

.G

D T

/2

(Topsoil)

SANDY LEAN CLAY trace of gravel, grey, wet, rather stiff.

(Alluvium)

LEAN CLAY with SAND trace of iron staining, light grey, wet, rather stiff.

(Alluvium)

POORLY-GRADED SAND mostly medium grained, trace of gravel, grey, moist to waterbearing, loose to medium dense.

(Alluvium)

Trace of clay below about 14 feet.

End of boring.

Boring sealed upon completion.

CL

OL

CL

CL

SP

Elevations provided by Bolton & Menk, Inc.

MC = 16.3%

PP = 3.75 tsf

Water encountered at about 10 feet during drilling.

2.0

4.0

6.0

16.0

1192.3

1190.3

1188.3

1178.3

B-07 page 1 of 1

0.0

BORING: B-07

24387.24.IAM

Description of Materials

(ASTM D 2487/2488)

PROJECT:

1194.3

L O G O F B O R I N G

CHOSEN VALLEY TESTING

SCALE: 1" = 2'

BPF

24387.24.IAM

Factual Geotechnical Evaluation Proposed Wetland SE 1/4 Sec. 10 - T98N - R22W Fertile Township, Worth County, Iowa

See attached sketch

LOCATION:

WLUSCS

Symbol Tests and NotesDepthElev.

DATE: 11/4/2024

C V

T S

T A

N D

A R

D

.2 4.

IA

M

W

O R

T H

C O

U N

T Y

W E

T

LA

N D

G

P J

L O

G A

G N

N N

.G

D T

/2

(Topsoil)

SANDY LEAN CLAY trace of gravel, black, wet, soft to medium.

(B-Horizon)

LEAN CLAY trace of iron staining, brown, wet, soft.

(Alluvium) CLAYEY SAND to SANDY LEAN CLAY mostly medium grained, trace of gravel, trace of roots, trace of wood, grey, moist, loose.

(Alluvium)

POORLY-GRADED SAND mostly medium grained, trace of gravel, trace of clay, grey, moist, dense.

(Alluvium)

POORLY-GRADED SAND to CLAYEY SAND mostly medium grained, trace of gravel, brown, moist, medium dense.

(Alluvium)

POORLY-GRADED SAND mostly medium grained, trace of gravel, trace of clay, grey, moist, medium dense.

(Alluvium)

End of boring.

Boring sealed upon completion.

CL

OL

CL

CL

SC

CL

SP

SP

SC

SP

Elevations provided by Bolton & Menk, Inc.

PP = 2.5 tsf, MC = 25.7%

PP = 1.5 tsf

PP = 1.25 tsf

2.0

6.0

6.5

9.0

11.5

14.0

16.0

1196.1

1192.1

1191.6

1189.1

1186.6

1184.1

1182.1

B-08 page 1 of 1

0.0

BORING: B-08

24387.24.IAM

Description of Materials

(ASTM D 2487/2488)

PROJECT:

1198.1

L O G O F B O R I N G

CHOSEN VALLEY TESTING

SCALE: 1" = 2'

BPF

24387.24.IAM

Factual Geotechnical Evaluation Proposed Wetland SE 1/4 Sec. 10 - T98N - R22W Fertile Township, Worth County, Iowa

See attached sketch

LOCATION:

WLUSCS

Symbol Tests and NotesDepthElev.

DATE: 11/4/2024

C V

T S

T A

N D

A R

D

.2 4.

IA

M

W

O R

T H

C O

U N

T Y

W E

T

LA

N D

G

P J

L O

G A

G N

N N

.G

D T

/2

(Topsoil)

LEAN CLAY trace of sand, black, wet, meidum.

(B-Horizon)

SANDY LEAN CLAY trace of gravel, black, wet, soft.

(B-Horizon) LEAN CLAY trace of iron staining, grey to brown, wet, soft.

(Alluvium)

POORLY-GRADED SAND to CLAYEY SAND mostly medium grained, trace of gravel, brown, moist, loose.

(Alluvium)

POORLY-GRADED SAND with GRAVEL mostly medium grained, brown, moist, medium dense.

(Alluvium)

POORLY-GRADED SAND with LEAN CLAY mostly medium grained, trace of gravel, grey, moist, medium dense.

(Alluvium)

POORLY-GRADED SAND with GRAVEL and LEAN CLAY mostly medium grained, grey, moist to waterbearing, medium dense.

(Alluvium)

End of boring.

Boring sealed upon completion.

CL

OL

CL

CL

CL

SP

SC

SP

SP

CL

SP

Elevations provided by Bolton & Menk, Inc.

MC = 35.1%

PP = 2.0 tsf

Water encountered at about 14 feet during drilling.

1.5

4.0

5.0

6.5

9.0

11.5

14.0

16.0

1193.3

1190.8

1189.8

1188.3

1185.8

1183.3

1180.8

1178.8

B-09 page 1 of 1

0.0

BORING: B-09

24387.24.IAM

Description of Materials

(ASTM D 2487/2488)

PROJECT:

1194.8

L O G O F B O R I N G

CHOSEN VALLEY TESTING

SCALE: 1" = 2'

BPF

24387.24.IAM

Factual Geotechnical Evaluation Proposed Wetland SE 1/4 Sec. 10 - T98N - R22W Fertile Township, Worth County, Iowa

See attached sketch

LOCATION:

WLUSCS

Symbol Tests and NotesDepthElev.

DATE: 11/4/2024

C V

T S

T A

N D

A R

D

.2 4.

IA

M

W

O R

T H

C O

U N

T Y

W E

T

LA

N D

G

P J

L O

G A

G N

N N

.G

D T

/2

(Topsoil)

SANDY LEAN CLAY trace of gravel, black, wet, medium.

(B-Horizon)

LEAN CLAY trace of gravel, trace of iron staining, trace of sand, grey to dark grey, wet, rather soft.

(Alluvium)

CLAYEY SAND mostly medium grained, trace of gravel, brown, moist, loose.

(Alluvium)

POORLY-GRADED SAND to CLAYEY SAND mostly medium grained, trace of gravel, brown to grey, moist, medium dense to dense.

(Alluvium)

With GRAVEL below about 11.5 feet.

POORLY-GRADED SAND with GRAVEL mostly medium graiend, grey, moist to waterbearing, medium dense.

(Alluvium)

End of boring.

Boring sealed upon completion.

CL

CL

CL

SC

SP

SC

SP

Elevations provided by Bolton & Menk, Inc.

PP = 2.25 tsf, MC = 26.6%

PP = 1.25 tsf, MC = 29.8%

Water encountered at about 14 feet during drilling.

1.5

4.0

6.5

9.0

14.0

16.0

1196.2

1193.7

1191.2

1188.7

1183.7

1181.7

B-10 page 1 of 1

0.0

BORING: B-10

24387.24.IAM

Description of Materials

(ASTM D 2487/2488)

PROJECT:

1197.7

L O G O F B O R I N G

CHOSEN VALLEY TESTING

SCALE: 1" = 2'

BPF

24387.24.IAM

Factual Geotechnical Evaluation Proposed Wetland SE 1/4 Sec. 10 - T98N - R22W Fertile Township, Worth County, Iowa

See attached sketch

LOCATION:

WLUSCS

Symbol Tests and NotesDepthElev.

DATE: 11/4/2024

C V

T S

T A

N D

A R

D

.2 4.

IA

M

W

O R

T H

C O

U N

T Y

W E

T

LA

N D

G

P J

L O

G A

G N

N N

.G

D T

/2

Slightly Organic SANDY LEAN CLAY trace of gravel, black, wet.

SANDY LEAN CLAY trace of gravel, black, wet.

(B-Horizon)

Trace of roots below about 2 feet.

SANDY LEAN CLAY trace of gravel, dark brown, wet.

(Alluvium) Trace of iron staining below about 4 feet.

CLAYEY SAND to SILTY SAND mostly fine grained, trace of gravel, light brown to light grey, moist.

(Alluvium) End of boring.

Boring sealed upon completion.

CL

OL

CL

CL

SC

SM

Elevations estimated from Iowa DNR LiDAR.

1.0

3.0

5.0

6.0

HA-1 page 1 of 1

0.0

BORING: HA-1

24387.24.IAM

Description of Materials

(ASTM D 2487/2488)

PROJECT:

L O G O F B O R I N G

CHOSEN VALLEY TESTING

SCALE: 1" = 2'

BPF

24387.24.IAM

Factual Geotechnical Evaluation Proposed Wetland SE 1/4 Sec. 10 - T98N - R22W Fertile Township, Worth County, Iowa

See attached sketch

LOCATION:

WLUSCS

Symbol Tests and NotesDepthElev.

DATE: 3/21/2025

C V

T S

T A

N D

A R

D

.2 4.

IA

M

W

O R

T H

C O

U N

T Y

W E

T

LA

N D

G

P J

L O

G A

G N

N N

.G

D T

/2

Slightly Organic SANDY LEAN CLAY trace of gravel, black, wet.

(Topsoil) CLAYEY SAND mostly medium grained, trace of gravel, brown to dark brown, moist.

(Alluvium) POORLY-GRADED SAND to CLAYEY SAND mostly medium grained, trace of gravel, brown, moist.

(Alluvium) POORLY-GRADED SAND mostly medium grained, trace of gravel, trace of clay, brown, moist.

(Alluvium) End of boring.

Boring sealed upon completion.

CL

OL

SC

SP

SC

SP

Elevations estimated from Iowa DNR LiDAR.

1.0

2.0

3.0

4.0

HA-2 page 1 of 1

0.0

BORING: HA-2

24387.24.IAM

Description of Materials

(ASTM D 2487/2488)

PROJECT:

L O G O F B O R I N G

CHOSEN VALLEY TESTING

SCALE: 1" = 2'

BPF

24387.24.IAM

Factual Geotechnical Evaluation Proposed Wetland SE 1/4 Sec. 10 - T98N - R22W Fertile Township, Worth County, Iowa

See attached sketch

LOCATION:

WLUSCS

Symbol Tests and NotesDepthElev.

DATE: 3/21/2025

C V

T S

T A

N D

A R

D

.2 4.

IA

M

W

O R

T H

C O

U N

T Y

W E

T

LA

N D

G

P J

L O

G A

G N

N N

.G

D T

/2

Slightly Organic LEAN CLAY black, wet.

(Topsoil)

CLAYEY SAND mostly medium grained, dark brown, moist.

(Alluvium)

POORLY-GRADED SAND to CLAYEY SAND mostly medium grained, dark brown, moist.

(Alluvium)

End of boring.

Boring sealed upon completion.

CL

OL

SC

SP

SC

Elevations estimated from Iowa DNR LiDAR.

1.0

2.5

5.0

HA-3 page 1 of 1

0.0

BORING: HA-3

24387.24.IAM

Description of Materials

(ASTM D 2487/2488)

PROJECT:

L O G O F B O R I N G

CHOSEN VALLEY TESTING

SCALE: 1" = 2'

BPF

24387.24.IAM

Factual Geotechnical Evaluation Proposed Wetland SE 1/4 Sec. 10 - T98N - R22W Fertile Township, Worth County, Iowa

See attached sketch

LOCATION:

WLUSCS

Symbol Tests and NotesDepthElev.

DATE: 3/21/2025

C V

T S

T A

N D

A R

D

.2 4.

IA

M

W

O R

T H

C O

U N

T Y

W E

T

LA

N D

G

P J

L O

G A

G N

N N

.G

D T

/2

Slightly Organic LEAN CLAY black, wet to very wet.

(Topsoil) SANDY LEAN CLAY trace of roots, black, wet.

(B-Horizon)

CLAYEY SAND to SILTY SAND mostly fine grained, trace of gravel, brown to dark brown, moist.

(Alluvium)

CLAYEY SAND mostly fine grained, trace of gravel, brown, moist.

(Alluvium) End of boring.

Boring sealed upon completion.

CL

OL

CL

SC

SM

SC

Elevations estimated from Iowa DNR LiDAR.

1.0

2.0

4.0

5.0

HA-4 page 1 of 1

0.0

BORING: HA-4

24387.24.IAM

Description of Materials

(ASTM D 2487/2488)

PROJECT:

L O G O F B O R I N G

CHOSEN VALLEY TESTING

SCALE: 1" = 2'

BPF

24387.24.IAM

Factual Geotechnical Evaluation Proposed Wetland SE 1/4 Sec. 10 - T98N - R22W Fertile Township, Worth County, Iowa

See attached sketch

LOCATION:

WLUSCS

Symbol Tests and NotesDepthElev.

DATE: 3/21/2025

C V

T S

T A

N D

A R

D

.2 4.

IA

M

W

O R

T H

C O

U N

T Y

W E

T

LA

N D

G

P J

L O

G A

G N

N N

.G

D T

/2

N

Boring Location Sketch

SE ¼ Sec. 10 – T98N – R22W

Fertile Township, Worth County, Iowa

24387.24.IAM

Legend

Boring Location

B-01

B-05

B-02

B-03 B-04

B-06

B-07

B-08

B-10

B-09

HA-3

HA-4

HA-2

HA-1

1.9731.973

W

W1.9731.973

Safety Factor 0.000 0.250 0.500 0.750 1.000 1.250 1.500 1.750 2.000 2.250 2.500 2.750 3.000 3.250 3.500 3.750 4.000 4.250 4.500 4.750 5.000 5.250 5.500 5.750 6.000+

-150 -100 -50 0 50 100 150 200

1.5561.556

W

1.5561.556

Safety Factor 0.000 0.250 0.500 0.750 1.000 1.250 1.500 1.750 2.000 2.250 2.500 2.750 3.000 3.250 3.500 3.750 4.000 4.250 4.500 4.750 5.000 5.250 5.500 5.750 6.000+

1.5681.568

W1.5681.568

Safety Factor 0.000 0.250 0.500 0.750 1.000 1.250 1.500 1.750 2.000 2.250 2.500 2.750 3.000 3.250 3.500 3.750 4.000 4.250 4.500 4.750 5.000 5.250 5.500 5.750 6.000+

1.2271.227

W

1.2271.227

Safety Factor 0.000 0.250 0.500 0.750 1.000 1.250 1.500 1.750 2.000 2.250 2.500 2.750 3.000 3.250 3.500 3.750 4.000 4.250 4.500 4.750 5.000 5.250 5.500 5.750 6.000+

2.3932.393

W2.3932.393

Safety Factor 0.000 0.250 0.500 0.750 1.000 1.250 1.500 1.750 2.000 2.250 2.500 2.750 3.000 3.250 3.500 3.750 4.000 4.250 4.500 4.750 5.000 5.250 5.500 5.750 6.000+

-100 -75 -50 -25 0 25 50 75 100 125 150

1.9251.925

W

1.9251.925

Safety Factor 0.000 0.250 0.500 0.750 1.000 1.250 1.500 1.750 2.000 2.250 2.500 2.750 3.000 3.250 3.500 3.750 4.000 4.250 4.500 4.750 5.000 5.250 5.500 5.750 6.000+

1.7931.793

W

1.7931.793

Safety Factor 0.000 0.250 0.500 0.750 1.000 1.250 1.500 1.750 2.000 2.250 2.500 2.750 3.000 3.250 3.500 3.750 4.000 4.250 4.500 4.750 5.000 5.250 5.500 5.750 6.000+

1.4961.496

W

1.4961.496

Safety Factor 0.000 0.250 0.500 0.750 1.000 1.250 1.500 1.750 2.000 2.250 2.500 2.750 3.000 3.250 3.500 3.750 4.000 4.250 4.500 4.750 5.000 5.250 5.500 5.750 6.000+

3.0893.089

W

3.0893.089

Safety Factor 0.000 0.250 0.500 0.750 1.000 1.250 1.500 1.750 2.000 2.250 2.500 2.750 3.000 3.250 3.500 3.750 4.000 4.250 4.500 4.750 5.000 5.250 5.500 5.750 6.000+

-125 -100 -75 -50 -25 0 25 50 75 100 125 150

2.1572.157

W

2.1572.157

Safety Factor 0.000 0.250 0.500 0.750 1.000 1.250 1.500 1.750 2.000 2.250 2.500 2.750 3.000 3.250 3.500 3.750 4.000 4.250 4.500 4.750 5.000 5.250 5.500 5.750 6.000+

2.9822.982

W

2.9822.982

Safety Factor 0.000 0.250 0.500 0.750 1.000 1.250 1.500 1.750 2.000 2.250 2.500 2.750 3.000 3.250 3.500 3.750 4.000 4.250 4.500 4.750 5.000 5.250 5.500 5.750 6.000+

1.9941.994

W

1.9941.994

Safety Factor 0.000 0.250 0.500 0.750 1.000 1.250 1.500 1.750 2.000 2.250 2.500 2.750 3.000 3.250 3.500 3.750 4.000 4.250 4.500 4.750 5.000 5.250 5.500 5.750 6.000+

1.8501.850

W

1.8501.850

Safety Factor 0.000 0.250 0.500 0.750 1.000 1.250 1.500 1.750 2.000 2.250 2.500 2.750 3.000 3.250 3.500 3.750 4.000 4.250 4.500 4.750 5.000 5.250 5.500 5.750 6.000+

-250 -200 -150 -100 -50 0 50 100 150 200

1.4191.419

W1.4191.419

Safety Factor 0.000 0.250 0.500 0.750 1.000 1.250 1.500 1.750 2.000 2.250 2.500 2.750 3.000 3.250 3.500 3.750 4.000 4.250 4.500 4.750 5.000 5.250 5.500 5.750 6.000+

1.4691.469

W

1.4691.469

Safety Factor 0.000 0.250 0.500 0.750 1.000 1.250 1.500 1.750 2.000 2.250 2.500 2.750 3.000 3.250 3.500 3.750 4.000 4.250 4.500 4.750 5.000 5.250 5.500 5.750 6.000+

1.2441.244

W

1.2441.244

Safety Factor 0.000 0.250 0.500 0.750 1.000 1.250 1.500 1.750 2.000 2.250 2.500 2.750 3.000 3.250 3.500 3.750 4.000 4.250 4.500 4.750 5.000 5.250 5.500 5.750 6.000+

-200 -150 -100 -50 0 50 100 150

GROUP

SYMBOL SOIL GROUP NAMES & LEGEND

PRIMARILY ORGANIC MATTER, DARK IN COLOR, AND ORGANIC ODOR

BLOWS/FOOT* CONSISTENCY

SAMPLE TYPES

Job No. 24387.24.IAM

GRAVELS WITH FINES

>12% FINES

2.0 - 4.0

OVER 4.0

TERM

Trace With

Modifier

0.50 - 1.0

1.0 - 2.0

0 - 0.25

0.25 - 0.50

GW

GP

GM

GC

SW

SP

SM

SC

CL

ML

OL

CH

MH

OH

PT

CLEAN GRAVELS

<5% FINES

WATER LEVEL (WITH TIME OF)

MEASUREMENT

0 - 4

4 - 10

10 - 30

30 - 50

OVER 50

LIQUID LIMIT (%)

CH

P

LA

S T

IC

IT

Y I

N D

E X

SIZE

< 12 in.

3 in. - 12 in.

#4 sieve to 3 in.

#200 sieve to #4 sieve

Passing #200 sieve

TERM

Boulder Cobble Gravel Sand

Silt or Clay

SAND & GRAVEL

CRITERIA FOR ASSIGNING SOIL GROUP NAMES

MC

OC

CN

DD

PP

RV

SA

P200

>50% OF COARSE

FRACTION PASSES

ON NO 4. SIEVE

RELATIVE DENSITY

(RECORDED AS BLOWS / 0.5 FT)

CL

SILT & CLAY

NUMBER OF BLOWS OF 140 LB HAMMER FALLING 30 INCHES TO DRIVE A 2 INCH O.D.

(1-3/8 INCH I.D.) SPLIT-BARREL SAMPLER THE LAST 12 INCHES OF AN 18-INCH DRIVE

(ASTM-1586 STANDARD PENETRATION TEST).

BLOWS/FOOT*

WELL-GRADED GRAVEL

POORLY-GRADED GRAVEL

SILTY GRAVEL

CLAYEY GRAVEL

WELL-GRADED SAND

POORLY-GRADED SAND

SILTY SAND

CLAYEY SAND

LEAN CLAY

SILT

ORGANIC CLAY OR SILT

FAT CLAY

ELASTIC SILT

ORGANIC CLAY OR SILT

PENETRATION RESISTANCE

Hollow Stem

LEGEND TO SOIL

DESCRIPTIONS

FINES CLASSIFY AS ML OR CL

FINES CLASSIFY AS CL OR CH

PI>7 AND PLOTS>"A" LINE

PI>4 AND PLOTS<"A" LINE

LL (oven dried)/LL (not dried)<0.75

PI PLOTS >"A" LINE

PI PLOTS <"A" LINE

LL (oven dried)/LL (not dried)<0.75

COMPRESSIVE

STRENGTH (TSF)

Chosen Valley Testing

CLEAN SANDS

<5% FINES

SANDS AND FINES

>12% FINES

INORGANIC

MOISTURE CONTENT

ORGANIC CONTENT

CONSOLIDATION

DRY DENSITY

POCKET PENETROMETER

R-VALUE

SIEVE ANALYSIS

% PASSING #200 SIEVE

LIQUID LIMIT

PLASTISITY INDEX

SWELL TEST

Unconsolidated Undrained triaxial

LL

PI

SW

UU

PERCENT

< 5 5 - 12 > 12

Relative Proportions of Fines

Standard Penetration Test

VERY SOFT

SOFT

RATHER SOFT

MEDIUM

RATHER STIFF

STIFF

VERY STIFF

HARD

UNIFIED SOIL CLASSIFICATION (ASTM D-2487/2488)

ML

MH

TEST SYMBOLS

PERCENT

< 15 15 - 29 > 30

ORGANIC

Relative Proportions of Sand and Gravel

0 - 1 2 - 3 4 - 5 6 - 8

9 - 12 13 - 16 17 - 30

OVER 30

INORGANIC

TERM

Trace With

Modifier

Grain Size Terminology

Cu>4 AND 1<Cc<3

Cu>4 AND 1>Cc>3

FINES CLASSIFY AS ML OR CL

FINES CLASSIFY AS CL OR CH

ORGANIC

VERY LOOSE

LOOSE

MEDIUM DENSE

DENSE

VERY DENSE

GRAVELS

0 10 20 30 40 50 60 70 80 90 100 110 120

MATERIAL

TYPES

Cu>6 AND 1<Cc<3

Cu>6 AND 1>Cc>3

C V

T

.2

.I

A M

W

O R

T H

C O

U N

T Y

W E

T L

A N

D

G P

J

/2

/2

PEAT

SANDS

SILTS AND CLAYS

LIQUID LIMIT>50

SILTS AND CLAYS

LIQUID LIMIT<50

>50% OF COARSE

FRACTION RETAINED

ON NO 4. SIEVE

HIGHLY ORGANIC SOILS

C O

A R

S E

-G R

A

IN

E D

S O

IL

S

R E

T A

IN

E

D O

N N

O . 2

S

IE

V E

F

IN

E -G

R A

IN

E

D S

O

IL

S

P

A S

S E

S N

O . 2

S

IE

V E

PLASTICITY CHART

"A " L

IN

E

CL-ML

Page: 10

Appendix G: HydroCAD Output

1S

Wetland Watershed

3S

Eastern Watershed

6S

Northwest Offsite Watershed

7S

Southwest Direct Watershed

10S

Northwest Direct Watershed

12S

Culvert Area

5R

Out Channel

2P

East Pool

4P

Culvert Storage

5P

Northwest Wetland

8P

Southwest Pool

9P

Northwest Pothole

11P

Culvert Storage

Routing Diagram for D Petersburg HydroCAD Prepared by Bolton & Menk, Inc, Printed 4/10/2026

HydroCAD® 10.20-5c s/n 00709 © 2023 HydroCAD Software Solutions LLC

Subcat Reach Pond Link

D Petersburg HydroCAD Printed 4/10/2026Prepared by Bolton & Menk, Inc

Page 2HydroCAD® 10.20-5c s/n 00709 © 2023 HydroCAD Software Solutions LLC

Rainfall Events Listing

Event# Event

Name

Storm Type Curve Mode Duration

(hours)

B/B Depth

(inches)

AMC

1 5 Yr MSE 24-hr 3 Default 24.00 1 3.90 2

2 10 Yr MSE 24-hr 3 Default 24.00 1 4.60 2

3 25 yr MSE 24-hr 3 Default 24.00 1 5.80 2

4 100 yr MSE 24-hr 3 Default 24.00 1 7.80 2

D Petersburg HydroCAD

Page 3HydroCAD® 10.20-5c s/n 00709 © 2023 HydroCAD Software Solutions LLC

Area Listing (all nodes)

Area

(acres)

CN Description

(subcatchment-numbers)

19.300 83 (1S, 3S)

3.670 100 (7S, 10S)

3.710 85 (7S, 10S)

1.200 80 (12S)

5.500 100 Pool (1S)

31.480 85 Row crops, straight row, Good, HSG C (6S)

64.860 86 TOTAL AREA

MSE 24-hr 3 5 Yr Rainfall=3.90"D Petersburg HydroCAD

Page 4HydroCAD® 10.20-5c s/n 00709 © 2023 HydroCAD Software Solutions LLC

Time span=0.00-48.00 hrs, dt=0.01 hrs, 4801 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN

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

Runoff Area=11.800 ac 46.61% Impervious Runoff Depth=2.92"Subcatchment 1S: Wetland Watershed Flow Length=125' Tc=11.9 min CN=91 Runoff=47.87 cfs 2.873 af

Runoff Area=13.000 ac 0.00% Impervious Runoff Depth=2.20"Subcatchment 3S: Eastern Watershed Flow Length=1,370' Tc=21.5 min CN=83 Runoff=30.84 cfs 2.383 af

Runoff Area=31.480 ac 0.00% Impervious Runoff Depth=2.37"Subcatchment 6S: Northwest Offsite Flow Length=1,540' Tc=26.3 min CN=85 Runoff=72.11 cfs 6.214 af

Runoff Area=3.530 ac 47.03% Impervious Runoff Depth=3.02"Subcatchment 7S: Southwest Direct Tc=5.0 min CN=92 Runoff=19.35 cfs 0.889 af

Runoff Area=3.850 ac 52.21% Impervious Runoff Depth=3.12"Subcatchment 10S: Northwest Direct Tc=5.0 min CN=93 Runoff=21.55 cfs 1.002 af

Runoff Area=1.200 ac 0.00% Impervious Runoff Depth=1.96"Subcatchment 12S: Culvert Area Tc=5.0 min CN=80 Runoff=4.60 cfs 0.196 af

Avg. Flow Depth=0.39' Max Vel=1.63 fps Inflow=4.89 cfs 0.385 afReach 5R: Out Channel n=0.025 L=80.0' S=0.0050 '/' Capacity=6,533.92 cfs Outflow=4.89 cfs 0.385 af

Peak Elev=1,197.01' Storage=7.563 af Inflow=50.33 cfs 4.870 afPond 2P: East Pool Primary=4.61 cfs 4.652 af Secondary=0.02 cfs 0.002 af Outflow=4.63 cfs 4.654 af

Peak Elev=1,199.79' Storage=1.066 af Inflow=30.84 cfs 2.383 afPond 4P: Culvert Storage…