9_26-07_FLO971628B - Final Hydrology & Hydraulics Report.pdf

Engineering Design Report

IDALS FLO971628B Wetland

Floyd, IA

March 24, 2025

Project No. 23-30398

R E P O R T F O R :

Iowa Department of Agriculture and

Land Stewardship

502 East 9th Street

Des Moines, IA 50319

F R O M :

ISG

Spencer Pech, PE

335 Cedar St Suite 200

Waterloo, Iowa 50701

319.234.1515

Spencer.Pech@ISGInc.com

IDALS FLO971628B Wetland – Engineering Design Report

Architecture + Engineering + Environmental + Planning Page i

SIGNATURE SHEET

I HEREBY CERTIFY THAT THESE CALCULATIONS WERE PREPARED BY ME OR UNDER MY DIRECT SUPERVISION AND THAT I AM A

DULY LICENSED PROFESSIONAL ENGINEER UNDER THE LAWS OF THE STATE OF IOWA.

Spencer Pech, PE

Project Engineer

Reg. No. P28161

ISG

335 Cedar St Suite 200

Waterloo, Iowa 50701

319.234.1515

IDALS FLO971628B

Floyd, IA

Engineer's Project Number: 23-30398

Dated this 24th day of March, 2025

SPENCER

DEAN PECH

P28161

LI

C

EN

SE

D PR

OFESSIONAL ENG

IN

EER

IOWA

Architecture + Engineering + Environmental + Planning Page ii

TABLE OF CONTENTS

SIGNATURE SHEET ..................................................................................................................................................................................... i

TABLE OF CONTENTS ................................................................................................................................................................................ ii

APPENDICES .............................................................................................................................................................................................. ii

Project Summary

Site Location & Assessment

Survey

Design Summary

Soils & On-Site Investigation

Hydrology & Hydraulics

Structural Design

Environmental Considerations

Erosion Control & Seeding

Safety Considerations

Land Rights

Permits

APPENDICES

Appendix A: Soil Report/Log and Geotechnical Report .......................................................................................................................... A

Appendix B: Operation & Maintenance Plan ........................................................................................................................................... B

Appendix C: Hydrology & Hydraulic Calculations ..................................................................................................................................... C

Architecture + Engineering + Environmental + Planning Page 1 of 5

PROJECT SUMMARY

Objective: Design and construction of a wetland to treat overland flow of water.

This will be accomplished by constructing a berm along a naturally occurring concentrated flow path. The berm will allow water to pond upstream of it, creating a wetland. The wetland elevation will be regulated by a sharp crested weir constructed from steel sheet piling. This weir will serve as the primary outlet of the wetland, while an overland flow path cut into the berm will serve as the secondary outlet. This wetland will allow for sedimentation and nutrient reduction, therefore reducing the overall pollution load to downstream waters. For this site, the receiving water is the Cedar River.

A sediment forebay is included in this project as an additional effort to aid in the reduction of sediment and sediment bound phosphorus before entering the wetland.

SITE LOCATION & ASSESSMENT

The project site is located in the SW ¼ of the NW ¼ of Section 28, T97N, R16W in Floyd County, Iowa. The site is situated to the

West of the Canadian National Railway and East of Ocean Ave. The existing site receives overland flow from intermittent streams with a drainage area totaling 174 acres, of which approximately 100 acres are privately tiled. A desktop review and assessment using soil maps, historical aerial imagery, and LiDAR information was performed by ISG.

The initial site assessment included a review of survey, tile maps and information acquired from the landowner, and other site constraints identified by the landowner. Due to the landowner’s desire to retain farmland on the North side of the site, the location of the berm and wetland pool was limited. Review of constraints led us to develop two initial wetland concepts for the project, one excavated and one natural concept.

SURVEY

A topographical survey was performed by ISG in March 2024. The survey was conducted using a base-rover GPS in Iowa Regional

Coordinate System and NAVD 88. Control was established with RTK GPS methods. One (1) benchmark was set for control. Major features were collected, and general topo was made with a grid pattern approximately 50’x50’ or adjusted based on natural change in elevation observed in the field. The topo grid included the dam footprint, proposed pool area, and existing stream. Topo survey was used for everything except planning and watershed delineation, in which LiDAR elevations were utilized. It is anticipated that additional temporary control will be set if machine control is requested by the hired contractor. ISG performed an additional survey to locate and document section corners for easement plat development in August 2024.

DESIGN SUMMARY

The design is for a nutrient removal wetland. During the initial landowner meeting and subsequent design meetings, the

Landowner’s and IDALS’ goals were discussed, and input was given on the design approach. ISG prepared two (2) site concept options that were provided to IDALS for review and consideration. Due to the landowner’s desire to retain farmland to the North of the proposed wetland, the second concept was agreed as the best approach. This concept is what ultimately led to the design of the site as shown in this report. During the preliminary design stage, ISG noted that the recommended wetland pool to watershed ratio of 0.5% was not being met with the current concept. To remedy this ISG provided IDALS with a “Expanded Pool” concept. Due to excess spoil wasting area on site, the benefit of this expanded pool was determined to be greater than the additional construction cost. During final design, the expanded pool concept was used.

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A portion of the design of this project was dedicated to agricultural drain tiles. The landowner provided ISG with maps of private tile in both fields adjacent to the proposed wetland area. According to the materials provided and survey collected, the private tile outlets were located downstream of our proposed site. To ensure the proposed site would receive as much hydrology as possible, ISG designed private tile intercept lines on both the North and South sides of the site. The lines were designed assuming that all existing private tile has a maximum of 3-feet of cover depth from top of pipe. The proposed tile was calculated to have a drainage coefficient of at least 0.5 inches per day (in/day) and to outlet at least 1-foot above our permanent pool elevation.

There will be a drawdown structure included in the proposed design to allow for controlled drainage of the wetland in scenarios that may require, such as general maintenance or sediment removal.

Soils & On-Site Investigation

On August 22nd, 2024, Terracon performed soil boring at the site. The results of the soil borings showed that the site mostly consists of sandy lean clay with occasional sand seams with increasing stiffness with depth. Terracon noted that there are some areas of partly organic material, specifically in the designated borrow area. If material were to be utilized from this area, it would need to be properly mixed with sandy lean clay to be suitable for use.

The full geotechnical report from Terracon can be found in Appendix A.

Hydrology & Hydraulics

DESIGN PARAMETERS AND PROCEDURE

A study of site hydrology and hydraulics was completed prior to the development of the structural components of the FLO971628B wetland. As part of the study, the drainage area was reviewed, and stage storage analysis was completed based on a combination of survey and LIDAR data. Land use and management practices were determined through site visits and aerial photography. This wetland will treat the overland flow from approximately 174 acres of agricultural lands in Floyd County. All survey data for this project was gathered using the Iowa Regional Coordinate System, Zone 2 and vertical datum NAVD88.

The existing system and proposed wetland modifications were modeled using HydroCAD 10.20-3c software, due to the watershed size and expected model complexity. The system is represented through a series of nodes and links to represent the wetland, the intermittent streams, and their respective catchments.

The curve number for the catchments were assumed to be 85, which is based on the standard value for a field planted with straight row crops with a Hydrologic Soil Group of “C”. Time of concentration was calculated within HydroCAD for each catchment.

The storage volume for the wetland area was determined from Civil3D after final grading was completed. This volume includes the sediment forebay.

Design storms and rainfall data used to generate the NRCS 24-hour MSE3 rainfall distributions for the project area were obtained from the NRCS National Engineering Handbook Figure IA2-25. See Appendix C for more information. Runoff calculations in the model were performed using the SCS TR-20. Given rainfall data, HydroCAD models the rainfall events, and the resulting flows and water elevations are produced within HydroCAD. The storm events modeled include the 2-, 5-, 10-, 25-, 50-, and 100-year events.

Since the contributing catchments have low times of concentration due to their topography and surface type, the wetland was expected to have a large storm bounce relative to the upstream watershed. Freeboard to the top of the berm from the design storm elevation was provided, and a surface overflow is graded into the berm as an additional conservative measure. See Table

1 below for specifics.

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See Appendix C for more information on model inputs.

Structural Design

EARTHEN EMBANKMENT/DIKE

The earthen embankment designed is considered a class IV dike per CPS 356 and is classified as a Class A Non-Inventory Dam per the National Engineering Manual. The maximum embankment height is 7.5 feet and in combination with total storage, is not subject to Iowa DNR Dam Safety. The primary spillway was designed to handle 100% of the flow up to the 25-year design storm.

An auxiliary spillway was designed with its crest elevation slightly above the 25-year flood surface elevation as a conservative measure. The top of berm height was set to 1090’, 2 feet above the auxiliary spillway crest elevation per CPS 378.

SHEET PILE WEIR

The primary spillway was designed as a sheet pile weir. In accordance with CPS 410, the freeboard for headwalls and sidewalls was set to 0.5’ higher than the design discharge peak elevation. In this case the design discharge peak elevation used is the auxiliary spillway crest elevation which is 1087.99’, therefore the top of the sidewalls was set to 1088.49’. CPS 410 also requires a minimum of 1.0 foot between the top of the sidewalls and the top of the settled embankment. With the top of the berm set to

1090’, this leaves 1.51’ between the two and satisfies CPS 410. The steel sheet pile weir was designed as a cantilevered wall in accordance with US Army Corp of Engineers technical guidance. The weir was designed with a FoS of 1.15 to retain liquid loading up to an elevation of 1089.01, slightly above the elevation of auxiliary spillway. The weir was designed to resist liquid loading and active soil pressures, soil properties used were taken from Terracon geotechnical engineering report 13245077 dated Dec 6th, 2024. The wall performance and required embedment was analyzed and required sheet pile properties and embedment elevations were calculated and are detailed in the construction drawings.

VERTICAL STRUCTURES

The water control structure is designed as vertical 48” aluminized CMP structure. The CMP structure will include stop logs welded to the interior of the riser that can be removed as needed to drain the wetland, most typically for cleaning purposes. To add weight to resist buoyancy and stress from flood flows, a concrete base and aggregate infill is proposed.

For the 100-year storm event, the high-water elevation within the wetland was determined to be 1188.24 feet.

See Table 1. Wetland Design Datasheet below for detailed design information. Refer to Appendix C for the HydroCAD report.

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Table 1. Wetland Design Data Sheet

Design Parameter Value(s) Units

Drainage Area 174 Acres

Wetland Pool Area 1.63 Acres

Deep Water Area (>3 ft deep) 0.09 Acres

Normal Pool Elevation / Primary

Spillway Elevation

1086.00 / 1086.00 Feet

Average Pool Depth 1.43 Feet

Maximum Pool Depth 6.50 Feet

Pool Storage 1.83 Acre-Feet

Berm Elevation 1090.00 Feet

Berm Storage 21.34 Acre-Feet

Length of Berm 425 Feet

Auxiliary Spillway Elevation 1088.00 Feet

Auxiliary Spillway Width 20 Feet

Weir Width 30 Feet

Drop Height (Primary Spillway

Elevation – Stilling Basin Lowest

Elevation)

7.5

Feet

Height of Dam (Berm Elevation –

Stilling Basin Lowest Elevation)

9.50 Feet

Stilling Basin Length 30 Feet

Time of Concentration 1.03 Hours

Weighted Runoff Curve Number 85 -----

25-year Storm Design Flow 310 CFS

100-year Storm Design Flow 447 CFS

100-year Flood Surf. Elevation 1088.24 Feet

Estimated Sediment Storage 99 Years

Total Easement Area 8.14 Acres

ANALYSIS OF UPSTREAM IMPACT

Due to the nature of the wetland design, there will be no upstream impacts with regard to peak flow and storm bounce. All private tiles in the fields adjacent to the wetland will be rerouted with a new intercept line acting as a header for the existing private tile.

All private tile outlets will be a minimum of 1-foot above permanent pool elevation, include a CMP outlet to prevent damage during controlled burns, and include an animal guard to prevent animals from travelling up the pipe. This will not adversely affect the drainage of the existing private tile.

ANALYSIS OF DOWNSTREAM CHANNEL

The wetland will outlet via a sheet pile weir structure and flow west through an existing 4-foot by 8-foot reinforced concrete (RC) box culvert under Ocean Ave. This culvert then flows to an intermittent stream flow path and eventually to the Cedar Rider. The culvert under Ocean Avenue was analyzed for capacity and was determined to have excess capacity to handle flow from our proposed site. The proposed wetland will not significantly increase peak flow downstream from existing conditions.

Delivery of sediment and nutrients downstream to the Cedar River is expected to decrease due to the nature and design of the sediment and nutrient removal wetland.

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Environmental Considerations

There are no anticipated negative impacts to threatened or endangered species as a result of the proposed project. The shallow pool will provide conditions favorable to wetland biota, and the easement area will be seeded with native grasses and forbs that will provide habitat benefits to wildlife and pollinators.

Waste material from the excavated area will be disposed of on-site, adjacent to the easement area.

Erosion Control & Seeding

Due to the amount of material to be excavated, it is necessary to provide measures for erosion control to prevent premature siltation of the wetland area and open ditch downstream of the site. During construction, silt fence will be installed along the stockpiling area. Storm drain inlet protection will be installed around the intake structures within the pool area and straw wattle installed downstream of the stilling basin in order to avoid transport of sediment to the open ditch downstream. Immediately following final grading, the easement area is to be seeded and fertilized in accordance with specification IA-06 to provide stability to slopes and bare earth. In addition, all excavated and earthfill areas with slope of 4:1 or greater are to be mulched and crimped to prevent erosion until establishment of the permanent vegetation.

Safety Considerations

The contractor is responsible for safety on the work site and providing all necessary safety measures for the protection of life, as required by regulating agencies. The contractor is to contact Iowa One Call for utility locations a minimum of two (2) business days prior to any excavation/construction. When not in operation, the contractor will be responsible for securing all equipment and materials stored on site.

Land Rights

The proposed easement area will consist of one parcel, owned by Jerad and Amber Stricker.

Permits

IDALS accepted responsibility of procuring any USACE Section 404 permits or other permits from regulatory agencies. The contractor will be responsible for obtaining a permit for construction activities occurring in Floyd County road right-of-way, if any.

Construction Oversight

A construction inspection plan is included within sheet C0-20 of the construction plans.

Operation & Maintenance Plan – Refer to Appendix B: Operation & Maintenance Plan

Architecture + Engineering + Environmental + Planning Appendix A

Appendix A: Soil Report/Log and Geotechnical Report

United States Department of Agriculture

A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants

Custom Soil Resource Report for

Floyd County, Iowa

FLO971628B

Natural Resources Conservation Service

February 7, 2025

Preface Soil surveys contain information that affects land use planning in survey areas.

They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers.

Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment.

Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions.

The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations.

Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/ portal/nrcs/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/?

cid=nrcs142p2_053951).

Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations.

The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey.

Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information.

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require http://www.nrcs.usda.gov/wps/portal/nrcs/main/soils/health/ http://www.nrcs.usda.gov/wps/portal/nrcs/main/soils/health/ https://offices.sc.egov.usda.gov/locator/app?agency=nrcs http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/?cid=nrcs142p2_053951 http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/?cid=nrcs142p2_053951 alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer.

Contents Preface How Soil Surveys Are Made Soil Map

Soil Map Legend Map Unit Legend Map Unit Descriptions

Floyd County, Iowa 84—Clyde silty clay loam, 0 to 3 percent slopes 781C—Lourdes loam, 5 to 9 percent slopes 783B—Cresco loam, 2 to 5 percent slopes 798B—Protivin loam, 1 to 4 percent slopes

References

How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity.

Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA.

The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape.

Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil-vegetation-landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries.

Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units).

Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil scientists classified and named the soils in the survey area, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research.

The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas.

Soil scientists make many field observations in the process of producing a soil map.

The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil-landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil-landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded.

These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape.

Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties.

While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field-observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management.

Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil.

Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date.

After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and

Custom Soil Resource Report identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately.

Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit.

Soil Map

520100 520140 520180 520220 520260 520300 520340 520380 520420 520460 520500 520540

520100 520140 520180 520220 520260 520300 520340 520380 520420 520460 520500 520540

43° 11' 38'' N

5'

'' W 43° 11' 38'' N

4'

9' ' W

43° 11' 28'' N

5'

'' W

43° 11' 28'' N

4'

9' ' W

N

Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 15N WGS84 0 100 200 400 600

Feet 0 30 60 120 180

Meters Map Scale: 1:2,090 if printed on A landscape (11" x 8.5") sheet.

Soil Map may not be valid at this scale.

MAP LEGEND MAP INFORMATION

Area of Interest (AOI) Area of Interest (AOI)

Soils Soil Map Unit Polygons

Soil Map Unit Lines

Soil Map Unit Points

Special Point Features Blowout

Borrow Pit

Clay Spot

Closed Depression

Gravel Pit

Gravelly Spot

Landfill

Lava Flow

Marsh or swamp

Mine or Quarry

Miscellaneous Water

Perennial Water

Rock Outcrop

Saline Spot

Sandy Spot

Severely Eroded Spot

Sinkhole

Slide or Slip

Sodic Spot

Spoil Area

Stony Spot

Very Stony Spot

Wet Spot

Other

Special Line Features

Water Features Streams and Canals

Transportation Rails

Interstate Highways

US Routes

Major Roads

Local Roads

Background Aerial Photography

The soil surveys that comprise your AOI were mapped at 1:15,800.

Warning: Soil Map may not be valid at this scale.

Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale.

Please rely on the bar scale on each map sheet for map measurements.

Source of Map: Natural Resources Conservation Service Web Soil Survey URL:

Coordinate System: Web Mercator (EPSG:3857)

Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required.

This product is generated from the USDA-NRCS certified data as of the version date(s) listed below.

Soil Survey Area: Floyd County, Iowa Survey Area Data: Version 30, Aug 29, 2024

Soil map units are labeled (as space allows) for map scales 1:50,000 or larger.

Date(s) aerial images were photographed: Sep 5, 2021—Oct 15, The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident.

Map Unit Legend

Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI

84 Clyde silty clay loam, 0 to 3 percent slopes

7.1 86.8%

781C Lourdes loam, 5 to 9 percent slopes

0.0 0.3%

783B Cresco loam, 2 to 5 percent slopes

0.0 0.1%

798B Protivin loam, 1 to 4 percent slopes

1.0 12.8%

Totals for Area of Interest 8.1 100.0%

Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit.

A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class.

Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils.

Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape.

The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas.

An identifying symbol precedes the map unit name in the map unit descriptions.

Each description includes general facts about the unit and gives important soil properties and qualities.

Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement.

Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series.

Some map units are made up of two or more major soils or miscellaneous areas.

These map units are complexes, associations, or undifferentiated groups.

A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps.

The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example.

An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha-Beta association, 0 to 2 percent slopes, is an example.

An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example.

Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example.

Floyd County, Iowa

84—Clyde silty clay loam, 0 to 3 percent slopes

Map Unit Setting National map unit symbol: 2shby Elevation: 660 to 1,440 feet Mean annual precipitation: 32 to 37 inches Mean annual air temperature: 44 to 49 degrees F Frost-free period: 155 to 195 days Farmland classification: Prime farmland if drained

Map Unit Composition Clyde and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit.

Description of Clyde

Setting Landform: Drainageways Landform position (two-dimensional): Toeslope Landform position (three-dimensional): Base slope Down-slope shape: Linear Across-slope shape: Concave Parent material: Erosional sediments fine-loamy till over loamy till

Typical profile A - 0 to 17 inches: silty clay loam AB - 17 to 23 inches: silty clay loam Bg1 - 23 to 28 inches: clay loam Bg2 - 28 to 41 inches: silty clay loam Bg3 - 41 to 44 inches: sandy loam 2BCg - 44 to 62 inches: loam 2BC - 62 to 79 inches: loam

Properties and qualities Slope: 0 to 3 percent Surface area covered with cobbles, stones or boulders: 0.5 percent Depth to restrictive feature: More than 80 inches Drainage class: Poorly drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Very low to moderately low (0.00 to 0.14 in/hr) Depth to water table: About 0 to 12 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum content: 15 percent Maximum salinity: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water supply, 0 to 60 inches: High (about 11.2 inches)

Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 2w Hydrologic Soil Group: C/D

Ecological site: R104XY012IA - Wet Upland Drainageway Sedge Meadow Forage suitability group: Level Swale, Neutral (G104XS001MN) Other vegetative classification: Level Swale, Neutral (G104XS001MN) Hydric soil rating: Yes

Minor Components

Clyde, frequently flooded Percent of map unit: 5 percent Landform: Drainageways Landform position (two-dimensional): Backslope Landform position (three-dimensional): Head slope Down-slope shape: Linear Across-slope shape: Concave Ecological site: R104XY012IA - Wet Upland Drainageway Sedge Meadow Other vegetative classification: Level Swale, Neutral (G104XS001MN) Hydric soil rating: Yes

Floyd Percent of map unit: 5 percent Landform: Drainageways Landform position (two-dimensional): Footslope Landform position (three-dimensional): Base slope Down-slope shape: Concave Across-slope shape: Linear Ecological site: R104XY005IA - Loamy Upland Prairie Other vegetative classification: Ponded If Not Drained (G104XS013MN) Hydric soil rating: No

Klossner Percent of map unit: 5 percent Landform: Fens on drainageways Landform position (two-dimensional): Toeslope Landform position (three-dimensional): Base slope Down-slope shape: Convex Across-slope shape: Convex Ecological site: R104XY001IA - Organic Sedge Meadow Other vegetative classification: Organic (G104XS014MN) Hydric soil rating: Yes

781C—Lourdes loam, 5 to 9 percent slopes

Map Unit Setting National map unit symbol: fmhs Elevation: 950 to 1,400 feet Mean annual precipitation: 29 to 37 inches Mean annual air temperature: 45 to 52 degrees F Frost-free period: 145 to 195 days Farmland classification: Farmland of statewide importance

Map Unit Composition Lourdes and similar soils: 95 percent Minor components: 5 percent Estimates are based on observations, descriptions, and transects of the mapunit.

Description of Lourdes

Setting Landform: Hillslopes Landform position (two-dimensional): Shoulder, backslope Landform position (three-dimensional): Side slope Down-slope shape: Convex Across-slope shape: Linear Parent material: Loamy sediments over subglacial till

Typical profile Ap - 0 to 8 inches: loam E - 8 to 11 inches: loam BE - 11 to 15 inches: loam 2Bt1 - 15 to 18 inches: loam 2Bt2 - 18 to 22 inches: clay loam 2Bt3 - 22 to 31 inches: clay loam 2Bt4 - 31 to 44 inches: clay loam 2BC - 44 to 51 inches: clay loam 2C - 51 to 76 inches: clay loam

Properties and qualities Slope: 5 to 9 percent Depth to restrictive feature: More than 80 inches Drainage class: Moderately well drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately low to moderately high (0.14 to 1.42 in/hr) Depth to water table: About 48 to 72 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum content: 15 percent Available water supply, 0 to 60 inches: High (about 9.9 inches)

Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 3e Hydrologic Soil Group: C Ecological site: R104XY007IA - Loamy Upland Savanna Hydric soil rating: No

Minor Components

Riceville Percent of map unit: 5 percent Landform: Hillslopes Landform position (two-dimensional): Backslope, shoulder Landform position (three-dimensional): Side slope Down-slope shape: Concave Across-slope shape: Linear Ecological site: R104XY007IA - Loamy Upland Savanna

Hydric soil rating: No

783B—Cresco loam, 2 to 5 percent slopes

Map Unit Setting National map unit symbol: 2y8pw Elevation: 520 to 1,310 feet Mean annual precipitation: 23 to 41 inches Mean annual air temperature: 43 to 54 degrees F Frost-free period: 135 to 210 days Farmland classification: All areas are prime farmland

Map Unit Composition Cresco and similar soils: 90 percent Minor components: 10 percent Estimates are based on observations, descriptions, and transects of the mapunit.

Description of Cresco

Setting Landform: Interfluves Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down-slope shape: Convex Across-slope shape: Linear Parent material: Erosional sediments fine-loamy till over till

Typical profile Ap - 0 to 8 inches: loam A - 8 to 13 inches: loam BA - 13 to 17 inches: loam 2Bw - 17 to 25 inches: loam 2Bt - 25 to 40 inches: clay loam 2BC - 40 to 47 inches: clay loam 2C - 47 to 60 inches: clay loam

Properties and qualities Slope: 2 to 5 percent Depth to restrictive feature: More than 80 inches Drainage class: Moderately well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Very low to moderately low (0.00 to 0.14 in/hr) Depth to water table: About 48 to 72 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum content: 15 percent Maximum salinity: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water supply, 0 to 60 inches: Low (about 5.9 inches)

Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 2e Hydrologic Soil Group: C Ecological site: R104XY005IA - Loamy Upland Prairie Hydric soil rating: No

Minor Components

Protivin Percent of map unit: 5 percent Landform: Interfluves Landform position (two-dimensional): Summit, backslope Landform position (three-dimensional): Interfluve Down-slope shape: Convex Across-slope shape: Linear Ecological site: R104XY005IA - Loamy Upland Prairie Hydric soil rating: No

Olin Percent of map unit: 5 percent Landform: Interfluves Landform position (two-dimensional): Summit Landform position (three-dimensional): Interfluve Down-slope shape: Convex Across-slope shape: Linear Ecological site: R104XY010IA - Sandy Upland Prairie Hydric soil rating: No

798B—Protivin loam, 1 to 4 percent slopes

Map Unit Setting National map unit symbol: 2y8px Elevation: 520 to 1,310 feet Mean annual precipitation: 23 to 41 inches Mean annual air temperature: 43 to 54 degrees F Frost-free period: 135 to 210 days Farmland classification: All areas are prime farmland

Map Unit Composition Protivin and similar soils: 90 percent Minor components: 10 percent Estimates are based on observations, descriptions, and transects of the mapunit.

Description of Protivin

Setting Landform: Interfluves Landform position (two-dimensional): Summit, backslope Landform position (three-dimensional): Interfluve

Down-slope shape: Convex Across-slope shape: Linear Parent material: Erosional sediments fine-loamy till over till

Typical profile Ap - 0 to 8 inches: loam A1 - 8 to 11 inches: loam A2 - 11 to 15 inches: loam BA - 15 to 19 inches: loam Bw - 19 to 23 inches: loam 2Bt1 - 23 to 35 inches: clay loam 2Bt2 - 35 to 40 inches: clay loam 2Bt3 - 40 to 45 inches: clay loam 2C - 45 to 60 inches: clay loam

Properties and qualities Slope: 1 to 4 percent Depth to restrictive feature: More than 80 inches Drainage class: Somewhat poorly drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): Very low to moderately low (0.00 to 0.14 in/hr) Depth to water table: About 12 to 42 inches Frequency of flooding: None Frequency of ponding: None Calcium carbonate, maximum content: 15 percent Maximum salinity: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water supply, 0 to 60 inches: Low (about 5.8 inches)

Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 2e Hydrologic Soil Group: C/D Ecological site: R104XY005IA - Loamy Upland Prairie Hydric soil rating: No

Minor Components

Clyde Percent of map unit: 5 percent Landform: Drainageways Landform position (two-dimensional): Toeslope Landform position (three-dimensional): Base slope Down-slope shape: Linear Across-slope shape: Concave Ecological site: R104XY012IA - Wet Upland Drainageway Sedge Meadow Hydric soil rating: Yes

Cerlin Percent of map unit: 5 percent Landform: Interfluves Landform position (two-dimensional): Backslope, shoulder, summit Landform position (three-dimensional): Crest Down-slope shape: Convex Across-slope shape: Linear Ecological site: R104XY005IA - Loamy Upland Prairie Hydric soil rating: No

References American Association of State Highway and Transportation Officials (AASHTO).

2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition.

American Society for Testing and Materials (ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00.

Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31.

Federal Register. July 13, 1994. Changes in hydric soils of the United States.

Federal Register. September 18, 2002. Hydric soils of the United States.

Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States.

National Research Council. 1995. Wetlands: Characteristics and boundaries.

Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service.

U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/national/soils/?cid=nrcs142p2_054262

Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577

Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580

Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section.

United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1.

United States Department of Agriculture, Natural Resources Conservation Service.

National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ home/?cid=nrcs142p2_053374

United States Department of Agriculture, Natural Resources Conservation Service.

National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/ detail/national/landuse/rangepasture/?cid=stelprdb1043084 http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_054262 http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_054262 http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577 http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577 http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580 http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580…