Assessment and Management Strategies for the Rathbun …...Cha rit on and South F ork Charito n Riv...

Assessment and Management Strategies Assessment and Management Strategies for thefor the

Rathbun Lake WatershedRathbun Lake Watershed

RATHBUN LAKE WATERSHED (354,000 Acres)South Central Iowa

CLARKE

LUCAS

MONR OE

DECATUR

WAYNE

APPANOOSE

RATHB UN LAKE

Char iton Ri ver

Sout h Fo rk Chari ton River

IOWA

Sour ce: Char it on Val ley R C&D Iowa DN R N RG IS

USDA N atur al Resour ces C onser vati on S ervi ce Pr epared By: Rat hbun Regi onal Water A sso ciat ion

N

5 0 5 Miles

REGIONAL LOCATION

Cou nty Boun dary

Rath bun Lake ( 904 ft. e lev atio n -- Nor mal Poo l)

Cha riton and South F ork Charito n River s

Rath bun Lake Water shed (35 4,000 Acres)

LE GEND

A COOPERATIVE EFFORT BY THE MEMBERS AND PARTNERS OF THEA COOPERATIVE EFFORT BY THE MEMBERS AND PARTNERS OF THE

RATHBUN LAND AND WATER ALLIANCERATHBUN LAND AND WATER ALLIANCE

DECEMBER 2001DECEMBER 2001

SECTION I CONTENTS AND PROJECT COOPERATORS Contents SECTION I

CONTENTS AND PROJECT COOPERATORS

Page I-1

SECTION II

INTRODUCTION

Page II-1

SECTION III

BACKGROUND ON RATHBUN LAKE AND WATERSHED

Page III-1

SECTION IV

DELINEATION OF THE RATHBUN LAKE WATERSHED

Page IV-1

SECTION V

INVENTORY OF POTENTIAL CONTAMINANT SOURCES IN THE RATHBUN LAKE WATERSHED

Page V-1 SECTION VI

ANALYSIS OF THE SUSCEPTIBILITY OF RATHBUN LAKE TO POTENTIAL CONTAMINANT SOURCES

Page VI-1 SECTION VII

MANAGEMENT STRATEGIES FOR THE RATHBUN LAKE WATERSHED

Page VII-1 APPENDIX A

WATER QUALITY PROTECTION FACT SHEETS

APPENDIX B

TIME OF TRAVEL FOR SOUTH FORK CHARITON AND CHARITON RIVERS WITHIN RATHBUN WATERSHED

APPENDIX C

ENVIRONMENTAL ASSESSMENT FOR THE RATHBUN LAKE WATERSHED: SAMPLING DESIGN, METHODS AND RESULTS

APPENDIX D

MODELING SWITCHGRASS PRODUCTION EFFECTS ON RUNOFF WATER QUALITY

APPENDIX E

ASSESSMENT OF THE ECOLOGICAL INTEGRITY OF STREAM CORRIDORS IN THE RATHBUN LAKE WATERSHED USING THE STREAM VISUAL ASSESSMENT PROTOCOL

_ Assessment and Management Strategies for the Rathbun Lake Watershed I-1

SECTION I CONTD. Project Cooperators The assessment and management strategies for the Rathbun Lake watershed have been a cooperative effort by members and partners of the Rathbun Land and Water Alliance. Alliance members include:

• Rathbun Regional Water Association, Inc.

• Appanoose, Clarke, Decatur, Lucas, Monroe, and Wayne Soil and Water Conservation Districts

• Appanoose, Clarke, Decatur, Lucas, Monroe, and Wayne Counties

• Chariton Valley Resource Conservation and Development, Inc.

Alliance partners include:

• City of Corydon

• Iowa Farm Bureau Federation

• ADLM Counties Environmental Health

• Leopold Center for Sustainable Agriculture

• Iowa Association of Water Agencies 2

• Trees Forever

• Iowa State University

• Texas Tech University

• Iowa Department of Agriculture and Land Stewardship’s Division of Soil Conservation

• Iowa Department of Natural Resources

• Iowa Department of Economic Development

• Southern Iowa Development and Conservation Authority

• US Army Corps of Engineers

Alliance members and partners discuss findings of the assessment.

• USDA Natural Resources Conservation Service

• USDA Farm Service Agency

• USDA Rural Development

• US Department of Energy

• US Environmental Protection Agency

• US Geological Survey Alliance members and partners that contributed funds and technical assistance to perform the assessment and develop management strategies included:

• Rathbun Regional Water Association, Inc.

• Appanoose, Clarke, Decatur, Lucas, Monroe, and Wayne Soil and Water Conservation Districts

• Iowa State University

• Iowa Department of Agriculture and Land Stewardship’s Division of Soil Conservation

• Iowa Department of Natural Resources

• US Army Corps of Engineers

• USDA Natural Resources Conservation Service

• US Department of Energy (DE-FC36-96GO10148)

• US Environmental Protection Agency (CP99758401) The assessment and management strategies document was assembled for the Alliance by: Martin Braster, Environmental Management Specialist, Rathbun Regional Water Association, 641-647-2416 Tyler Jacobsen, Geographic Information System Specialist, Rathbun Regional Water Association, 641-647-2416 Vince Sitzmann, Environmental Specialist, Iowa Department of Agriculture and Land Stewardship’s Division of Soil Conservation, 641-872-1350 For additional copies, revisions, and information contact these individuals. Assistance from the Rathbun Land and Water Alliance is provided on a nondiscriminatory basis. The information in this document has been subjected to the US EPA’s peer and administrative review process and has been approved for publication as an EPA document. Support provided by the US DOE does not constitute an endorsement of views expressed in this document.

Assessment and Management Strategies for the Rathbun Lake Watershed I-2

SECTION II

SECTION II INTRODUCTION Purpose of the Assessment and Management Strategies for the Rathbun Lake Watershed The Rathbun Land and Water Alliance’s mission is to foster a voluntary approach driven by landowners, water users, and public and private organizations to protect and enhance land, water, and economic resources in the Rathbun Lake region. The assessment and management strategies for the Rathbun Lake watershed provide the Alliance the knowledge and direction needed to assemble the financial and technical resources required to accomplish this mission. Rathbun Lake is the water supply for the Rathbun Regional Water Association (RRWA). RRWA is the largest rural water system in Iowa. Rathbun Lake also provides recreation, flood damage reduction, fish and wildlife habitat, downstream water quality improvement, storage for supplementing navigational flows, and water for the Iowa Department of Natural Resources’ (DNR) Rathbun Fish Hatchery. Rathbun Lake’s ability to support these uses is threatened by sources of water pollution in its watershed. This pollution is caused by eroded soil, nutrients, pesticides, and bacteria. The assessment for Rathbun Lake identifies and prioritizes potential sources of pollution in the lake’s watershed. Assessment results have been used to develop management strategies for the watershed that will reduce and prevent water pollution from these potential sources.

The assessment identifies and prioritizes potential sources of water pollution in Rathbun Lake. State of Iowa’s Source Water Assessment and Protection Program The assessment and management strategies are intended to fulfill requirements of the Source Water Assessment and Protection Program and Implementation Strategy for the State of Iowa. The Source Water Assessment and Protection Program and Implementation Strategy was prepared by the Iowa DNR to address the 1996 Safe Drinking Water Act Amendments’ requirements for source water delineation and assessment (P.L. 104-182, Section 1453).

Sections of the Assessment and Management Strategies The assessment and management strategies for the Rathbun Lake watershed consists of the following sections: Background on Rathbun Lake and watershed: Information has been assembled that describes the general features of Rathbun Lake and its importance as a drinking water supply, characteristics of the lake’s watershed, water quality issues in the lake, and water quality protection efforts underway. Delineation of the Rathbun Lake watershed: The boundaries of the entire watershed of Rathbun Lake have been identified as well as the boundaries of sub-watersheds and other priority areas such as buffer zones that were used to perform the assessment. Inventory of potential contaminant sources in the Rathbun Lake watershed: An inventory has been completed to identify all potential sources of contaminants such as sediment, nutrients, chemicals, and bacteria that could cause water pollution in Rathbun Lake. Analysis of the susceptibility of Rathbun Lake to potential contaminant sources: The potential sources of contaminants have been evaluated and prioritized based on such factors as location in the watershed and type of contaminant source to reflect the relative risk of these sources to cause water pollution in Rathbun Lake. Management strategies for the Rathbun Lake watershed: Alternative strategies have been developed for reducing and preventing water pollution in Rathbun Lake from potential sources of contaminants in the watershed.

Assessment results have been used to develop management strategies that will reduce and prevent water pollution in Rathbun Lake.

Assessment and Management Strategies for the Rathbun Lake Watershed II-1

SECTION III

SECTION III BACKGROUND ON RATHBUN LAKE AND WATERSHED Rathbun Lake Rathbun Lake is the primary source of water for the Rathbun Regional Water Association (RRWA). In addition to being an important source of drinking water, the 11,000 acre lake provides recreational opportunities for one million visitors annually, flood damage reduction for 150,000 acres of downstream land, and fish and wildlife habitat in the lake and on 21,000 acres of adjacent public land. Rathbun Lake also provides downstream water quality improvement, storage for supplementing navigational flows, and water for the Iowa Department of Natural Resources’ (DNR) Rathbun Fish Hatchery.

Rathbun Lake provides recreation for one million visitors annually. (Photo courtesy ACOE)

Rathbun Lake is located on the Chariton River in south central Iowa. Figures 1 and 2 at the end of this section identify the location of Rathbun Lake and its watershed. Rathbun Lake was developed in the late 1960s by the US Army Corps of Engineers (ACOE). The ACOE is responsible for managing Rathbun Lake, associated lake facilities, and adjacent public land. The Iowa DNR has designated the segment of the Chariton River on which Rathbun Lake is located a high quality resource water that warrants special protection.

The Iowa DNR has designated the segment of the Chariton River on which Rathbun Lake is located a high quality resource water that warrants special protection.

Rathbun Regional Water Association (RRWA) RRWA is one of the largest rural water systems in the United States and the largest system in Iowa. RRWA provides close to six million gallons of water daily to over 60,000 people for residential, agricultural, and business use in 18 counties and more than 40 communities in Iowa and Missouri. Figure 3 at the end of this section identifies the service area of RRWA.

RRWA is one of the largest rural water systems in the United States and the largest system in Iowa. RRWA’s water treatment plant draws raw water from the Chariton River directly below Rathbun Lake. RRWA has expanded its water treatment plant capacity to over eight million gallons per day in response to continued growth in the demand for water. In addition to the water treatment plant, the RRWA system currently consists of nearly 6,500 miles of pipeline, 30 elevated storage tanks, and 33 pumping stations.

RRWA water treatment plant located downstream of Rathbun Lake. (Photo courtesy RRWA)

Assessment and Management Strategies for the Rathbun Lake Watershed III-1

SECTION III CONTD. Watershed Characteristics Land use: The Rathbun Lake watershed consists of over 354,000 acres. Row crop production is the principal land use in the watershed. Corn and soybeans are the most commonly grown crops. Pasture and hayland are present on over one third of the land in the watershed and consist primarily of cool season grasses. Woodland in the watershed is concentrated along upland drainageways and in lowland areas and usually includes stands of oak, hickory, eastern cottonwood, and silver maple. Table 1 presents land use information for the Rathbun Lake watershed.

The counties in the Rathbun Lake watershed are among the least prosperous in Iowa. These counties suffer some of the highest poverty and unemployment rates and lowest levels of income and farm sales in the state. Approximately 15,000 people live in the Rathbun Lake watershed. There are nine communities and an estimated 857 farms in the watershed. The majority of farms are family owned and operated. Almost all of the residents in the watershed rely on Rathbun Lake for their drinking water.

Table 1. Land Use in the Rathbun Lake Watershed

Cropland

Cropland in the Conservation

Reserve Program

Pasture and

Hayland

Woodland

Other (Urban, Water,

Road, etc.) Percent of Watershed

30

12

38

13

7

Acres

106,910

40,985

135,685

44,183

26,297

Approximately 468 livestock operations are located in the watershed. The majority of these are beef cattle operations that rely primarily on pasture for grazing. There are 13 publicly owned areas in the watershed consisting of over 24,000 acres. Most notable in terms of size are the Rathbun Lake Project Area, Honey Creek State Park, Colyn Marsh Area, Bobwhite State Park, and Lucas County Greenbelt Complex. Demographics: The six counties in the Rathbun Lake watershed include Appanoose (52,063 acres, 15 percent of the watershed), Clarke (15,500 acres, four percent of the watershed), Decatur (7,280 acres, two percent of the watershed), Lucas (90,997 acres, 26 percent of the watershed), Monroe (6,523 acres, two percent of the watershed) and Wayne (181,697 acres, 51 percent of the watershed).

Counties in the Rathbun Lake watershed suffer from some of the highest poverty and unemployment rates and lowest levels of income and farm sales in Iowa.

Geology, soils, and climate: The landscape in the Rathbun Lake watershed is characterized by rolling uplands, integrated drainage, and occasional broad alluvial plains. Most soils in the watershed formed in loess, glacial till, or alluvium. A few of the soils formed in colluvium, eolian sand, or shale residuum. The majority of soils in the Rathbun Lake watershed have characteristics that limit their potential uses. This limitation arises from a prevalence of soils that are highly erosive, shallow to root-restrictive zones, excessively wet, and inherently low in fertility. Table 2 on the following page presents general information about some of the more common soils in the Rathbun Lake watershed. The climate in south central Iowa and the Rathbun Lake watershed is classified as humid continental. Winters are cold and summers are quite hot. In winter the average temperature is 27 degrees Fahrenheit. In summer the average temperature is 73 degrees Fahrenheit. Total annual precipitation averages 35 inches of which nearly 70 percent usually falls in April through September. The average seasonal snowfall is 27 inches. The average length of a growing season is 160 days.


SECTION III CONTD.

Table 2. Common Soils in the Rathbun Lake Watershed

Soil

Percent of Watershed

Slope

Land Capability Class

Corn Suitability Rating

Adair 5% 5 - 14% IIIe and IVe 5 to 35 Arispe 5% 5 - 9% IIIe 50 to 55 Armstrong 2% 5 - 14% IIIe and IVe 5 to 31 Clarinda 11% 5 - 14% IVe 10 to 30 Edina 5% 0 - 2% IIIw 60 Gara 5% 9 - 25% IVe and VIe 5 to 43 Grundy 8% 2 - 9% IIe and IIIe 50 to 75 Haig 3% 0 - 2% IIw 70 Lamoni 5% 5 - 14% IIIe, IVe, and VIe 5 to 35 Olmitz 1% 5 - 9% IIIe 57 to 72 Pershing 2% 5 - 14% IIIe and IVe 31 to 67 Seymour 9% 2 - 9% IIIe 35 to 60 Shelby 9% 9 - 18% IIIe, IVe, and VIe 13 to 50 Vesser 1% 0 - 2% IIw 66 to 71

Water Quality Issues Available sources of information indicate that Rathbun Lake is being impacted by sources of water pollution in the lake’s watershed: Iowa DNR assessment for Rathbun Lake: The Iowa DNR’s assessment of lakes and streams has determined that Rathbun Lake and water bodies in its watershed, such as the Chariton River, Bob White Lake, Corydon Reservoir, and Honey Creek, are impacted by agricultural non-point sources of pollution. The assessment indicates that the ability of Rathbun Lake and these waters to be used for recreation, habitat, and drinking water is either threatened, partially supported, or not supported. Primary causes of this impairment include sediment accumulation, turbidity, pesticides, bacteria, and nutrients. Rathbun Lake water quality monitoring program: Results of water quality monitoring in Rathbun Lake and its tributaries indicate that high to very high levels of nutrients, suspended solids, herbicides, and bacteria impact the lake’s water supply, recreational, and habitat uses. A review of the monitoring results by the ACOE and Iowa State University (ISU) indicates that Rathbun Lake could reach a point at which it is unable to assimilate continued loading of silt, nutrients, and pesticides unless there is a reduction in sediment, herbicide, and fertilizer in runoff from the watershed.

Water quality monitoring indicates that Rathbun Lake could reach a point at which it is unable to assimilate continued loading of silt, nutrients, and pesticides unless there is a reduction in sediment, herbicide, and fertilizer in runoff from the watershed. Sediment studies in Rathbun Lake: Sediment studies conducted by the ACOE indicate that Rathbun Lake has lost a considerable portion of its sediment storage capacity. According to the studies, soil erosion on land in the watershed and erosion of the lake’s shoreline have caused sedimentation to occur in Rathbun Lake at a rate that is faster than that anticipated and used for the original sediment storage allocation. The ACOE estimates that this continued rate of loss in sediment storage could require a reallocation of the lake’s remaining capacity. A reallocation of Rathbun Lake’s storage capacity due to sedimentation may have detrimental impacts on the lake’s ability to support its many uses including water supply, recreation, wildlife habitat, and flood protection.


SECTION III CONTD. US EPA Section 303(d) List of Impaired Waters in Iowa: Rathbun Lake has been identified as a high priority water body on the US Environmental Protection Agency’s (EPA) Section 303(d) List of Impaired Waters in Iowa. According to the EPA, Rathbun Lake is on the impaired waters list primarily due to information indicating that levels of the herbicide atrazine in the lake exceed water quality standards. Water resources located in the Rathbun Lake watershed that are also included on the EPA Section 303(d) list include Bob White Lake, Corydon Reservoir, Brown’s Slough, and Colyn Marsh. Pollutants of greatest concern in these waters include sediment, nutrients, and atrazine. Water Quality Protection Efforts Local residents, city and county governments, and private organizations have been joined by public agencies at the state and federal levels to initiate efforts that will protect and improve water quality in Rathbun Lake. Water quality protection efforts underway include: • Creation and support of the Rathbun Land

and Water Alliance.

• Water quality monitoring program.

Water quality monitoring on a tributary stream that flows into Rathbun Lake. (Photo courtesy NRCS)

• Surveys of landowners in the watershed and water users in the RRWA service area.

• Development of a geographic information system for the watershed.

• Best management practice demonstration projects.

• Application of best management practices in priority areas.

Installation of a terrace system on cropland in the Rathbun Lake watershed.

• Construction of community wastewater

treatment facilities.

• Restoration of riparian and wetland habitat.

• Development of markets for farm products that encourage land use protective of water quality.

• Water quality information and education activities.

Fact sheets that describe current efforts to protect water quality in Rathbun Lake are included in Appendix A.


REGIONAL LOCATION

10 0 10 Miles

N

Source: Chariton Valley RC&D Iowa DNR NRGIS USDA Natural Resources Conservation Service ESRI Data and Maps Aug. 1999 US EPA Prepared By: Rathbun Regional Water Association

IOWA

MISSOURI

UPPER CHARITON HU #10280201 (870,133 Acres)RATHBUN LAKE WATERSHED (354,000 Acres)

IOWA

MISSOURI

Rathbun Lake Watershed (354000 Acres)

Upper Chariton River Watershed (HU #10280201) (870133 Acres)

LEGEND

Figure 1

RATHBUN LAKE WATERSHED (354,000 Acres)South Central Iowa

CLARKE

LUCAS

MONROE

DECATUR

WAYNE

APPANOOSE

RATHBUN LAKE

Chariton River

South Fork Chariton River

IOWA

Source: Chariton Valley RC&D Iowa DNR NRGIS USDA Natural Resources Conservation Service Prepared By: Rathbun Regional Water Association

N

5 0 5 Miles

REGIONAL LOCATION

Figure 2

County Boundary

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Rathbun Lake Watershed (354,000 Acres)

LEGEND

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Rathbun Lake

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Rathbun Lake (904 Ft. Pool Elevation)

City/Town (Green -- Bulk, Orange -- Franchise)

RRWA Service Area Boundaries (Distribution)

LEGEND

Figure 3

SECTION IV

SECTION IV DELINEATION OF THE RATHBUN LAKE WATERSHED The boundaries of the watershed of Rathbun Lake have been identified. The Rathbun Lake watershed has also been divided into 61 sub-watersheds. In addition, areas of special interest in the watershed have been identified. These areas include a buffer zone that is approximately one-quarter mile wide located next to Rathbun Lake and the rivers and streams in the watershed. Activities in the buffer zone have a relatively high potential to impact water quality due to their location next to rivers, streams, and the lake. The area of the watershed from which water in the rivers and streams flows into Rathbun Lake in 24 hours or less under average flow conditions has also been identified. This area provides an indication of the length of time that would be required for contaminants carried in water from the watershed to reach the lake. The sub-watersheds, buffer zone area, and 24-hour time of travel area identified in the Rathbun Lake watershed have been used in this assessment to locate, evaluate, and prioritize potential sources of contaminants that could cause water pollution in the lake. These areas have also been used to develop management strategies to reduce and prevent water pollution in Rathbun Lake from potential sources of contaminants in the watershed.

The sub-watersheds, buffer zone, and time of travel area have been used to prioritize potential sources of contaminants in the watershed…and develop management strategies to reduce and prevent water pollution in Rathbun Lake from these sources. Table 3 presents information about the Rathbun Lake watershed, sub-watersheds, buffer zone area, and 24-hour time of travel area. Figures 4, 5, 6, and 7 and Table 4 at the end of this section identify and describe the Rathbun Lake watershed, sub-watersheds, buffer zone area, and 24-hour time of travel area. The procedure used to determine the 24-hour time of travel area is described in Appendix B.

Table 3. Rathbun Lake Watershed Delineation Information

• Rathbun Lake watershed size:

354,062 acres

• Number and size of larger sub-watersheds in the Rathbun Lake watershed:

Four larger sub-watersheds, each of which is assigned a unique 11 digit hydrologic unit code

• Range in size of larger sub-watersheds:

8,706 acres to 151,612 acres

• Number and size of smaller sub-watersheds in the Rathbun Lake watershed:

61 smaller sub-watersheds, each of which is assigned a unique 14 digit hydrologic unit code

• Range in size of smaller sub-watersheds:

2,590 acres to 16,430 acres

• Size of the buffer zone area in the Rathbun Lake watershed:

226,122 acres or approximately 64% of the Rathbun Lake watershed

• Size of the 24-hour time of travel area in the Rathbun Lake watershed:

288,240 acres or approximately 81% of the Rathbun Lake watershed

Assessment and Management Strategies for the Rathbun Lake Watershed IV-1

IOWA


N

5 0 5 Miles

REGIONAL LOCATION

RATHBUN LAKE WATERSHED11 Digit Hydrologic Units MapSouth Central Iowa

CLARKE

LUCAS

MONROE

DECATUR

WAYNE

APPANOOSE

10280201040

10280201050

10280201070

10280201060

RATHBUN LAKE

County Boundary

11 Digit Hydrologic Units


Drainage


LEGEND

Figure 4

REGIONAL LOCATION

5 0 5 Miles

N


IOWA

CLARKE

LUCAS

MONROE

DECATUR

WAYNE

APPANOOSE

1

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910

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South Fork Chariton River

Chariton River

Figure 5

County Boundary

Primary Highway


Rathbun Lake Watershed 14 Digit Hydrologic Units

Drainage


LEGEND

RATHBUN LAKE WATERSHED14 Digit Hydrologic Units Map(Rathbun Lake Subwatersheds)South Central Iowa

Table 4

11 Digit Hydrologic Units 14 Digit Hydrologic Units(Rathbun Lake Subwatersheds)

Rathbun Lake Watershed Rathbun Lake Watershed

11 Digit Name Acres 8 Digit HUC ID Acres 14 Digit HUC #10280201040 Chariton River 146948.2 10280201 1 2589.632 1028020104021010280201050 Chariton River 8705.68 10280201 2 6089.331 1028020104020010280201070 Chariton River 46796.94 10280201 3 7369.71 1028020104022010280201060 Chariton River 151611.6 10280201 4 5256.643 10280201040160

5 4131.235 10280201050010Total 354062.4 6 3952.532 10280201040260

7 6058.842 102802010400808 5994.875 102802010401009 4574.445 10280201050020

10 3811.165 1028020104025011 6233.26 1028020104023012 4875.068 1028020104009013 6682.223 1028020104029014 7150.129 1028020104002015 5867.948 1028020104017016 5927.301 1028020104001017 4473.032 1028020104007018 14653.218 1028020107001019 3244.32 1028020104019020 3786.118 1028020104012021 4802.341 1028020104011022 4522.996 1028020107002023 4066.431 1028020104006024 7615.624 1028020104027025 4013.994 1028020104024026 4688.849 1028020107003027 6160.15 1028020104028028 6501.523 1028020107004029 3281.54 1028020104005030 4311.228 1028020104015031 3634.747 1028020104013032 4816.463 1028020104004033 16430.353 1028020107005034 4565.551 1028020104014035 5935.393 1028020106014036 4335.033 1028020104018037 6883.071 1028020106001038 7910.099 1028020106021039 5576.803 1028020106012040 5982.886 1028020104003041 7723.94 1028020106025042 4321.065 1028020106023043 4167.369 1028020106008044 4808.781 1028020106007045 6616.879 1028020106003046 4107.997 1028020106020047 5722.339 1028020106024048 6382.636 1028020106009049 7909.58 1028020106019050 6588.024 1028020106013051 7024.243 1028020106018052 7613.36 1028020106022053 5955.127 1028020106004054 6499.691 1028020106002055 6627.548 1028020106011056 7179.184 1028020106010057 4732.007 1028020106017058 7897.647 1028020106006059 4841.025 1028020106016060 3531.366 1028020106005061 5056.498 10280201060150

Total 354062.41

CLARKE

LUCAS

MONROE

DECATUR

WAYNE

APPANOOSE

RATHBUN LAKE

IOWA

Source: Chariton Valley RC&D Iowa State University Iowa DNR NRGIS USDA Natural Resources Conservation Service Prepared By: Rathbun Regional Water Association

N

5 0 5 Miles

REGIONAL LOCATION

RATHBUN LAKE WATERSHED24 Hour Time of Travel Area (Mean Flow)South Central Iowa

County Boundary


Drainage

Rathbun Lake 24 Hour Time of Travel Area (Mean Flow)


LEGEND

Figure 6

REGIONAL LOCATION

5 0 5 Miles

N

Source: Chariton Valley RC&D Iowa DNR NRGIS USDA Natural Resources Conservation Service

Prepared By: Rathbun Regional Water Association

IOWA

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LUCAS

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DECATUR

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RATHBUN LAKE

RATHBUN LAKE WATERSHED1/4 Mile Buffer Zone AreaSouth Central Iowa

County Boundary


Drainage

Rathbun Lake Watershed 1/4 Mile Buffer Zone Area


LEGEND

Figure 7

SECTION V

SECTION V INVENTORY OF POTENTIAL CONTAMINANT SOURCES IN THE RATHBUN LAKE WATERSHED

An inventory of all potential contaminant sources in the Rathbun Lake watershed has been completed. The purpose of this inventory was to identify and locate public and private facilities and land uses in the watershed that may be potential sources of contaminants such as sediment, nutrients, chemicals, and bacteria that could cause water pollution in Rathbun Lake. The inventory included potential point and non-point sources of water pollution. Point sources are those sources of water pollution that can be identified at specific locations, such as sewage discharge from an improperly functioning wastewater treatment facility. In contrast, non-point sources are sources of water pollution that cannot be identified as originating from a specific location, for example, farm chemicals in runoff from cropland in the watershed. The inventory of potential contaminant sources was completed using information available from existing records, databases, and maps maintained by public agencies and private organizations. Table 5 at the end of this section presents a list of sources of information used to conduct the inventory. In addition, extensive fieldwork was performed to collect information about potential contaminant sources in the watershed to complete the inventory.

The inventory identifies facilities and land uses in the watershed that may be potential sources of water pollution in Rathbun Lake.

Information was collected in the field about potential sources of contaminants.

Inventory of Potential Point Sources The potential point sources in the Rathbun Lake watershed that have been identified and located by the inventory include: Livestock feeding operations: Animal wastes from relatively large livestock feeding operations that may enter streams, rivers, and the lake can contain levels of nutrients, suspended solids, and microorganisms that could impair water quality. The inventory found that a very small number of the livestock feeding operations in the watershed are of the size that may meet the definition of a concentrated animal feeding operation according to current Clean Water Act regulations. These few operations have been included with the larger number of livestock operations identified as potential non-point sources of water quality impairment that are described on page V-4. Information collected about livestock feeding operations included location, type, size, and the presence of practices to reduce any impact from animal wastes on water quality. Figure 17 at the end of this section presents the number of livestock operations by sub-watershed. Road and railroad intersections: Accidents, construction, and maintenance activities along roads and railroads can be sources of contaminants such as petroleum products, chemicals, and sediment that may cause water pollution. A total of 1,032 road and railroad intersections with Rathbun Lake and the rivers and streams in its watershed have been identified. Information collected about the intersections included type such as bridge or culvert and road classification such as primary, secondary, or other. Figure 8 in this section identifies the location of these intersections in the watershed.

Assessment and Management Strategies for the Rathbun Lake Watershed V-1

SECTION V CONTD. Wastewater treatment facilities: Effluent that leaks or is discharged from lagoons and lines that are parts of wastewater treatment facilities may contain levels of nutrients, microorganisms, chemicals, and suspended solids that can impair water quality. Eight wastewater facilities are located in the watershed. Information collected about the facilities included type such as community or commercial. All of the facilities include lagoons. Figure 9 at the end of this section identifies the location of these facilities in the watershed. Septic system concentration areas: Sewage that is discharged from poorly operating septic systems may also contain levels of nutrients, microorganisms, and chemicals that can cause water pollution. Eighty-nine areas have been identified in the watershed with a concentration of five or more septic systems per square mile. Information collected about these areas included type such as incorporated community, unincorporated community, or rural residences and the size of the areas. Figure 10 in this section identifies the location of these septic system concentration areas in the watershed.

Eighty-nine areas have been identified in the watershed with a concentration of five or more septic systems per square mile. Institutional, retail, and industrial facilities: The storage, handling, use, and disposal of a variety of materials such as pesticides, paints, fuels, lubricants, solvents, and detergents by institutional, retail, and industrial facilities may be sources of contaminants that can impair water quality. A total of 74 institutional, retail, and industrial facilities are located in the watershed. Information collected about the facilities included type such as church, school, hospital, airports, government offices, retail agricultural businesses, and industrial plants. In addition, the locations of underground storage tanks have been identified. Figure 11 in this section identifies the location of these facilities in the watershed.

Recreational facilities: Visitor activities including the operation of vehicles and watercraft as well as construction and maintenance at recreational facilities may be sources of contaminants such as petroleum products, chemicals, sewage, and sediment that can cause water pollution. Fifty-four recreational facilities have been identified in the watershed. Information collected about the facilities included type such as boat ramps, campgrounds, marinas, and golf courses. Figure 12 in this section identifies the location of these facilities in the watershed.

Recreational facilities in the watershed such as boat ramps can be potential sources of contaminants that impair water quality. (Photo courtesy ACOE)

Residential and commercial areas: Runoff from residential and commercial areas may contain a variety of solid and liquid wastes such as chemical products used for household purposes and in retail businesses that can cause water pollution. Nine residential and commercial areas are located in the watershed. These areas are associated with the relatively more densely populated incorporated communities in the watershed. Figure 13 at the end of this section identifies the location of these areas in the watershed. Quarry sites: The operation and maintenance of equipment and processing of rock and other materials at quarry sites may be sources of contaminants including fuel, oil, and sediment that can impair water quality. Eight quarry sites are located in the watershed. Figure 14 in this section identifies the location of these sites in the watershed.


SECTION V CONTD. Shoreline erosion: Severe soil erosion caused by wave action and changes in pool elevation occurs on a large portion of the 150 miles of shoreline at Rathbun Lake. The US Army Corps of Engineers (ACOE) has determined that this shoreline erosion is the source of a significant portion of the soil that causes accelerated sedimentation and high levels of turbidity in Rathbun Lake.

Shoreline erosion is a significant source of the sediment that enters Rathbun Lake. (Photo courtesy NRCS)

Inventory of Potential Non-point Sources The types of potential non-point sources of contaminants in the Rathbun Lake watershed that have been identified and located by the inventory include: Eroded soil from land in the watershed: Information about soil properties, land use, vegetation, and farming practices has been collected and used to estimate the rates for sheet and rill erosion, gully erosion, and streambank erosion on land in sub-watersheds of the Rathbun Lake watershed. In addition, the amount of eroded soil that is carried in runoff from land in each sub-watershed to Rathbun Lake has been estimated. Procedures developed by the USDA Natural Resources Conservation Service (NRCS) were used to collect this information and make these estimates. The use of these procedures is described in Appendix C. Figure 15 at the end of this section identifies the locations of areas in the watershed where information about field conditions was collected.

Soil erosion on cropland in the watershed is a source of the sediment and chemicals that enter Rathbun Lake.

The amount of eroded soil that is carried in runoff from land in each sub-watershed to Rathbun Lake has been estimated. Chemicals from land in the watershed: A model has been developed and used to estimate the amounts of farm chemicals that are carried in runoff to Rathbun Lake from land in each of the sub-watersheds of the Rathbun Lake watershed. This model is the Soil and Water Assessment Tool or SWAT. Information about weather, topography, soil properties, land use, and farming practices was collected for use in the SWAT model. This information allowed the model to estimate the amounts of phosphorus, nitrogen, and atrazine that are carried in runoff to Rathbun Lake. The development and use of the SWAT model are described in Appendix D.

The SWAT model was used to estimate the amounts of farm chemicals carried in runoff to Rathbun Lake.


SECTION V CONTD. Impact of activities on riparian zones: Information has been collected at sites along rivers and streams in the Rathbun Lake watershed to determine the impact of activities on riparian zones. Information collected about the riparian zones included physical changes to the channel such as straightening, evidence of livestock presence, bank stability, water appearance, and canopy cover. This information was used with the Stream Visual Assessment Protocol developed by the USDA NRCS to evaluate the condition of the riparian zones and the related impacts on water quality in Rathbun Lake. The use of this procedure is described in Appendix E. Figure 16 in this section identifies the locations of sites where information about riparian zones was collected.

Information collected along streams and rivers was used to evaluate the condition of riparian zones in the watershed and related impacts on water quality in Rathbun Lake. Livestock operations: The inventory identified 468 livestock grazing and feeding operations in the Rathbun Lake watershed. Over 90 percent of these are beef cattle operations. The operations located in the watershed include: Livestock grazing operations: Livestock grazing operations may be sources of nutrients, microorganisms, suspended solids, and sediment that can impair water quality, particularly when livestock access to streams and rivers is not managed. An estimated 350 of the 468 operations in the watershed rely primarily on pasture for grazing with little or no confinement of livestock. In addition to location and type, information collected about the operations included size and livestock access to riparian zones that may impact water quality. Figure 17 at the end of this section presents the number of livestock grazing operations by sub-watershed.

Livestock feeding operations: Runoff from livestock feeding operations may contain levels of nutrients, microorganisms, suspended solids, and sediment that can impair water quality. An estimated 118 of the 468 operations in the watershed confine livestock, for example, in lots or buildings, for at least a portion of the year. In addition to location and type, information collected about the operations included size and the presence of practices to reduce any impact from livestock wastes on water quality. Figure 17 in this section presents the number of livestock feeding operations by sub-watershed.

Livestock operations in the watershed are potential sources of water quality impairment. (Photo courtesy Chariton Valley Beef)


Table 5

Source Water Assessment GIS Coverages -- Rathbun Lake WatershedCoverages Inventoried, Created, or Used for Rathbun Lake Watershed Assessment

Point SourceParent Coverage Name or Type Coverage Description Type Source Scale WWW Link To GIS Coverage and Metadata HoldingsAgdfac Animal waste control facilities with operating permits Point/Line IDNR Unknown http://www.igsb.uiowa.edu/nrgis/enviro.idcAirports Landing facilities in the state of Iowa as supplied by the FAA Point IDNR Unknown http://www.igsb.uiowa.edu/nrgis/cultural.idcBusiness Facilities Additional business facilities Point RRWA Unknown None -- Contact RRWA for more informationDnrlands Lands owned or managed by IDNR Polygon IDNR 1:24000 http://www.igsb.uiowa.edu/nrgis/cultural.idcHospital Hospitals in Iowa Point IDNR 1:24000 http://www.igsb.uiowa.edu/nrgis/cultural.idcIndustrial Facilities Discharge Industrial facilities discharge Point EPA Basins Unknown http://www.epa.gov/ost/ftp/basins/gis_data/huc/K12schls PreK-12 Schools in Iowa Point IDNR 1:24000 http://www.igsb.uiowa.edu/nrgis/cultural.idcMines96 Registered noncoal mineral production sites Polygon IDNR 1:100000 http://www.igsb.uiowa.edu/nrgis/physical.idcRecreational Facilities Boat ramps, rec area lagoons, marinas, etc. Point RRWA 1:24000 None -- Contact RRWA for more informationTiger Files Lndmkpnts for Counties Landmark Points Point USBOC 1:100000 http://www.geographynetwork.com/data/tiger2000/Toxic Release Inventory Toxic release inventory sites Point EPA Basins Unknown http://www.epa.gov/ost/ftp/basins/gis_data/huc/Ustsites Regulated underground storage tanks Point IDNR Varies http://www.igsb.uiowa.edu/nrgis/enviro.idcWwtp Waste water treatment plants Point IDNR 1:24000 http://www.igsb.uiowa.edu/nrgis/enviro.idc

Non-Point SourceParent Coverage Name or Type Coverage Description Type SourceUSGS NLCD Land Use Early 1990's Landuse/Landcover 30 meter cell grid Grid USGS Unknown http://landcover.usgs.gov/natllandcover.htmlTownship Soils Iowa Cooperative Soil Survey digital soils Polygon USDA NRCS 1:15840 http://icss.agron.iastate.edu/data.htm

Other CoveragesParent Coverage Name or Type Coverage Description Type Source8 Digit Hydrologic Units 8 Digit hydrologic units Polygon EPA Basins 1:250000 http://www.epa.gov/ost/ftp/basins/gis_data/huc/Basin_24 11 Digit hydrologic units Polygon USDA NRCS 1:24000 http://www.igsb.uiowa.edu/nrgis/enviro.idc14 Digit Hydrologic Units 14 Digit hydrologic units Polygon RRWA 1:24000 None -- Contact RRWA for more informationRathbun Lake 24 Hour Time of Travel 24 Hour Time of Travel to Rathbun Lake Polygon Area Polygon RRWA 1:100000 None -- Contact RRWA for more informationRathbun Lake 1/4 Mile Drainage Buffer 1/4 Mile Buffer of Stream Network Polygon RRWA 1:100000 None -- Contact RRWA for more informationLivestock Operations Inventory Livestock Inventory by 14 Digit Hydrologic Unit Point RRWA GPS to 1/4 Section None -- Contact RRWA for more informationSeptic Systems Concentrations 1/4 Mile Buffer of Potential Septic Tank Location -- 5 or more Polygon RRWA Varies None -- Contact RRWA for more information

Coverages for Individual CountiesParent Coverage Name or Type Coverage Description Type SourcePLSS (then county number) County section boundaries Polygon IDNR 1:24000 http://www.igsb.uiowa.edu/nrgis/county.htmRoads (then county number) County road network Polyline IDNR 1:100000 http://www.igsb.uiowa.edu/nrgis/county.htmRivers (then county number) County stream network Polyline IDNR 1:100000 http://www.igsb.uiowa.edu/nrgis/county.htmTopo (then county number) County topo lines Polyline IDNR 1:100000 http://www.igsb.uiowa.edu/nrgis/county.htm

Other Statewide CoveragesParent Coverage Name or TypeCounty State/County boundaries of the state of Iowa Polygon IDNR 1:24000 http://www.igsb.uiowa.edu/nrgis/cultural.idcIncorp Boundaries of Incorporated Cities and Towns in Iowa Polygon IDNR Large Scale http://www.igsb.uiowa.edu/nrgis/cultural.idcTownship Public Land Survey System Townships of Iowa Polygon IDNR 1:24000 http://www.igsb.uiowa.edu/nrgis/referenc.idcNational Trasportation Atlas Railroads Railroads for United States Line ESRI 1:100000 None -- ESRI Data and Maps CD, August 1999States State Boundaries Polygon ESRI Unknown None -- ESRI Data and Maps CD, August 1999

Source KeyEPA -- Environmental Protection AgencyIDNR -- Iowa Department of Natural ResourcesESRI -- Environmental Systems Research Institute, Inc.RRWA -- Rathbun Regional Water Association, Inc.USGS -- United States Geological SurveyUSDA NRCS -- United States Department of Agriculture Natural Resources Conservation ServiceUSBOC -- United States Bureau of Census

This digital data set was developed to support activities of the Rathbun Lake Watershed Assessment. Although efforts have been made to make it useful to the project, Rathbun Regional Water Association, Inc. (RRWA) and its partners working on the Assessment assume no responsibility for errors in the information. Similarly RRWA and its partners assume no responsibility for the consequences of inappropriate uses or interpretations of the data made by anyone to whom this data has been made available. RRWA and its partners assume no responsibility to inform users of any changes made to this data. Anyone using this data is advised that precision implied by the coverage may far exceed actual precision. Comments on this data are invited and RRWA would appreciate that documented errors be brought to staff attention.

REGIONAL LOCATION

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Source: Chariton Valley RC&D Iowa DNR NRGIS Iowa DOT Digital CAD Drawing Prepared By: Rathbun Regional Water Association

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LUCAS

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APPANOOSE

RATHBUN LAKE

RATHBUN LAKE WATERSHEDDrainage Intersections With Roads and Railroads InventorySouth Central Iowa

County Boundary

Bridge#

Railroad Bridge#

Culvert or Other Structure#


Railroad

Roads

Drainage (1:24000)


LEGEND

Figure 8

REGIONAL LOCATION

N

Source: Chariton Valley RC&D Iowa DNR NRGIS Prepared By: Rathbun Regional Water Association

IOWA

RATHBUN LAKE WATERSHEDWastewater Treatment Facilities InventorySouth Central Iowa

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LUCAS

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APPANOOSE

RATHBUN LAKE

1

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56

78

County Boundary

14 Digit Hydrologic Unit Boundary


Wastewater Treatment Facility#

Drainage


LEGEND

5 0 5 Miles

Figure 9

CLARKE

LUCAS

MONROE

DECATUR

WAYNE

APPANOOSE

RATHBUN LAKE

123

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5 0 5 Miles

REGIONAL LOCATION

RATHBUN LAKE WATERSHEDPotential Septic System Concentrations InventorySouth Central Iowa

County Boundary



Potential Septic System Concentrations

Drainage


LEGEND

Figure 10

REGIONAL LOCATION

5 0 5 Miles

N

Source: Chariton Valley RC&D Iowa DNR NRGIS US Bureau of Census Tiger Data US Army Corps of Engineers Wayne County SWCD EPA Basins Data Prepared By: Rathbun Regional Water Association

IOWA

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#Y

#Y

#Y

#Y#Y#Y#Y#Y#Y#Y

#Y

#Y

#Y#Y

#Y#Y

#Y

#Y#Y

#Y

#Y

#Y

#Y#Y

#Y

#Y

#Y#Y#Y#Y

#Y

#Y

#Y

#Y#Y#Y

#Y

#Y#Y#Y#Y

#Y#

#

#

#

#

#

#Y

#Y#Y

#Y#Y

#Y

#Y#Y

#Y

#Y

#Y#Y

#Y

#Y#Y

#YRATHBUN LAKE

Promise City

Allerton

Russell

Chariton

Corydon

Millerton

HumestonLe Roy

Derby

1

23

45

6

78

9

10

1112

13

14

15

37

16

17

18

19

21

22 23

24

25

26

2728

2930

313233

34

35

3839

40

41

42,43,44

45

46

47

48

49

5051

52

53

54

55

56

57

5859

60616263

6465

66

6768

6970

71

7273

74

75

36

CLARKE

LUCAS

MONROE

DECATUR

WAYNE

APPANOOSE

RATHBUN LAKE WATERSHEDInstitutional, Retail, and Industrial Facilities InventorySouth Central Iowa

County Boundary

Facility Type

Agricultural#Y

County#Y

Pesticide#Y

Airports#

Underground Storage Tanks#Y

Hospitals#Y

Schools#Y

Toxic Release Inventory Sites#Y

Additional Business and Facilities (Tiger Landmarks)

Churches#Y

Commercial#Y

Institutional#Y

Retail Commercial#Y



Drainage (1:24000)

City or Town


LEGEND

Figure 11

##

#

#

#

#

###

##

#

####

##

##

# #

######

##

#

##

##

#

##

#

##

##

##

#

##

#

#

#

#

#

#

APPANOOSE

WAYNE

DECATUR

MONROE

LUCAS

CLARKECLARKE

LUCAS

MONROE

DECATUR

WAYNE

APPANOOSE

1

23

4

5 6

789

1011

12

13141516

1719

202122 23

242627

282930

3132

33

34

353637

38

3940

41

4243

4445

4647

48

4950

51

25

18

52

53

54

IOWA

Source: Chariton Valley RC&D Iowa DNR NRGIS US Army Corps of Engineers Wayne County SWCD Prepared By: Rathbun Regional Water Association

N

5 0 5 Miles

REGIONAL LOCATION

RATHBUN LAKE WATERSHEDRecreational Facilites InventorySouth Central Iowa

County Boundary

Recreational Facilities

Boat Ramp#

Campground#

Golf Course#

Lagoon#

Marina#



Drainage (1:24000)


LEGEND

Figure 12

RATHBUN LAKE

CLARKE

LUCAS

MONROE

DECATUR

WAYNE

APPANOOSE

Derby

Le RoyHumeston

Millerton

Corydon

Chariton

Russell

Allerton

Promise City

IOWA


N

5 0 5 Miles

REGIONAL LOCATION

RATHBUN LAKE WATERSHEDResidential and Commercial Areas InventorySouth Central Iowa

County Boundary

Runoff from Residential and Commercial Areas



Drainage (1:24000)


LEGEND

Figure 13

REGIONAL LOCATION

5 0 5 Miles

N


IOWA

CLARKE

LUCAS

MONROE

DECATUR

WAYNE

APPANOOSE

RATHBUN LAKE

1

2

3

45

6

78

RATHBUN LAKE WATERSHEDQuarry Sites InventorySouth Central Iowa

County Boundary



Drainage (1:24000)

Quarry Sites


LEGEND

Figure 14

CLARKE

LUCAS

MONROE

DECATUR

WAYNE

APPANOOSE

104108111

205

305

801 409224

327316

707717

513519

903810

604

1404 1204 819525234

9171104424 610

616736 1212 1114

11241508

1309432 10141012

1605 14261711

12192105 1321

22011526

200418102011

1022

16231437 2311

23181718 2121 1832 22152023 2801190415352409

242116332324 3203

1725 2902 2129281126053013

2507 22221910

13412705

32182914 30203108 2513

36013114

25202715

261733091915 2444

35023225 2920

400734063119 3027

36082734

380528342623

35111884

37153419

3426 362038173909

39184106

420833434202

40264036 3726

44054607 4130

430233814214

37374510 4414 4613

4315 47073935

41443530

45284519

4430 48134626

47154321 3844

50195304

50304913

4823 5108 47245208

54205313

5322 50404833 4925

52255119

54314937

5510 52375701

58135441

56215141

55205716

57245826

56325903

583855305643 5918

60125925

60196105

6113

60256120

924

RATHBUN LAKE

IOWA

Source: Chariton Valley RC&D Iowa State University Iowa DNR NRGIS USDA Natural Resources Conservation Service


N

5 0 5 Miles

REGIONAL LOCATION

RATHBUN LAKE WATERSHEDInventory Sites for Soil Erosion and Sediment DeliverySouth Central Iowa

County Boundary

Inventory Sites for Soil Erosion and Sediment Delivery




LEGEND

Figure 15

5 0 5 Miles

N

Source: Chariton Valley RC&D Iowa State University Iowa DNR NRGIS USDA Natural Resources Conservation Service


IOWA

#Y#Y#Y

#Y

#Y#Y

#Y#Y #Y#Y

#Y #Y#Y #Y#Y #Y

#Y#Y

#Y#Y

#Y

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#Y

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#Y

#Y#Y #Y#Y

#Y

#Y

#Y

#Y

RATHBUN LAKE

104108

111

305

327316707

717 519604

1204 819234 1104424 616

12121124

15081014

1012

1605 1711 12191321

22011022

16231437 2311

2318 2121 183222151535 24212902

2811260530132507 2222

1910 13412914 3020 25133114

25202715

26171915

3225 3406 283426233511

1884

3419 3817390939184106

420833434202

3726 4130 3381

37374510 4414

4315 4707

3935

4528

45194430 4813

46264715

43215019

5304 50304913

48235208

54205313

53224833

52254937

5510 52375813

5621

5141

55205716

57245826

5632 5903

5838 5530 5918

6012 5925

60196105

61136120

924

222

426

514

834

911

1712 201620052108

2420

271231163219

3537

36093606 38074006

4010

5107

5413

1426

APPANOOSE

WAYNE

DECATUR

MONROE

LUCAS

CLARKE

RATHBUN LAKE WATERSHEDInventory Sites for Stream Visual Assessment ProtocolSouth Central Iowa

County Boundary

Inventory Sites for Stream Visual Assessment Protocol#Y




LEGEND

Figure 16

CLARKE

LUCAS

MONROE

DECATUR

WAYNE

APPANOOSE

RATHBUN LAKE

0

3 6

36

62 3 64115

88 37 78

6

12 55 135 1

5 45 662

5

6

5

6

61244

44

9912

7

77 11

2

10 888

58 2

10 3

2

4

0

12

01

6

1

0

5

2

1

23

4

1

24

5

1

1

1 11

2

0

20

11

4 2

3 52

2

1

3 12

2

4 31

11

0

3

2

3

14

10

0

5

33

2

21

0

IOWA

Source: Chariton Valley RC&D Wayne County Soil and Water Conservation District Iowa DNR NRGIS USDA Natural Resources Conservation Service


N

5 0 5 Miles

REGIONAL LOCATION

RATHBUN LAKE WATERSHEDLivestock Operations Inventory by SubwatershedSouth Central Iowa

County Boundary

Rathbun Lake Watershed Boundary


14 Digit Hydrologic Unit Livestock Operations Count

LEGEND

Blue Number -- Livestock Grazing Operations Count (350)

Green Number -- Livestock Feeding Operations Count (118)

Figure 17

SECTION VI

SECTION VI ANALYSIS OF THE SUSCEPTIBILITY OF RATHBUN LAKE TO POTENTIAL CONTAMINANT SOURCES

A susceptibility analysis has been completed to determine the relative risk posed to water quality in Rathbun Lake by the potential point and non-point sources of pollution identified in the watershed. The susceptibility analysis combined the watershed delineations described in Section IV and the potential contaminant inventory information from Section V. The results of the analysis can be used to prioritize the potential point and non-point sources of pollution that are the greatest relative threat to water quality in Rathbun Lake. The following approaches have been developed and used to perform the susceptibility analysis of potential point and non-point sources of contaminants.

The analysis determined the relative risk to water quality in Rathbun Lake from potential sources of pollution in the watershed. Susceptibility Analysis for Potential Point Sources In general, two factors were used to analyze the relative risk to water quality in Rathbun Lake from potential point sources of pollution in the watershed. These factors included location of the potential point source in the watershed and type of contaminant source. A risk score based on location was assigned to each potential point source according to the guidelines in Table 6. The location risk score for any potential point source ranged from two for least risk to 10 for greatest risk. Figure 18 in this section identifies the areas of the watershed that correspond to the location risk scores described in Table 6.

The location risk score was added to a type of contaminant source risk score for each potential point source. The type of contaminant source risk scores ranged from one for least risk to five for greatest risk. The type of contaminant source risk scores were obtained from the Land-Use Risk Potential Table in the Iowa Department of Natural Resources’ (DNR) Source Water Assessment and Protection Program and Implementation Strategy for the State of Iowa. Table 7 at the end of this section presents the type of contaminant source risk scores in the Land-Use Risk Potential Table. In addition, the combined risk score based on location and type for certain potential point sources was modified to more accurately assess the relative risk between possible sources within the same contaminant type categories. For example, the location and type of contaminant source risk score for each livestock operation was modified by the assignment of an additional risk score based on the size of the operation and whether it was primarily a grazing or feeding operation. The results of the susceptibility analysis for potential point sources of contaminants in the Rathbun Lake watershed are presented on the following page.

Location in the watershed and type of contaminant source were used to analyze the relative risk to water quality from potential point sources of pollution.

Table 6. Location Risk Score for Potential Point Sources

Assessment and Management Strategies for the Rathbun Lake Watershed VI-1

Location of Potential Point Source

Location Risk Score

• Located within 24-hour time of travel area:

Risk score of 5

• Located beyond 24-hour time of travel area:

Risk score of 1

• Located within 1/4 mile buffer zone area:

Risk score of 5

• Located beyond 1/4 mile buffer zone area:

Risk score of 1

SECTION VI CONTD. Livestock feeding operations: The analysis determined that the potential for livestock operations to impair water quality in Rathbun Lake is high in 15, moderate in 25, and low in 21 sub-watersheds. There are 186 livestock operations located in the 15 sub-watersheds with a high potential for impairing water quality. As described on page V-1, a very small number of the livestock feeding operations in the watershed are of the size that may meet the definition of a concentrated animal feeding operation according to current Clean Water Act regulations. These few operations have been included with the analysis of the larger number of livestock operations identified as potential non-point sources of water quality impairment described on page VI-4. Figure 39 and Table 17 at the end of this section present the results of the susceptibility analysis for livestock operations. Road and railroad intersections: The analysis indicated that the potential for contaminants from road and railroad intersections to impair water quality is high for 282, moderate for 578, and low for 172 intersections. Figure 19 and Table 8 in this section present the results of the analysis for these intersections. Wastewater treatment facilities: The analysis determined that the potential for water quality impairment is high for seven and moderate for one of the wastewater treatment facilities in the watershed. Figure 20 and Table 9 in this section present the results of the susceptibility analysis for wastewater treatment facilities. Septic system concentration areas: The analysis found that the potential for water pollution from concentrations of septic systems in the watershed is high for 26, moderate for 56, and low for seven areas. Figure 21 and Table 10 at the end of this section present the results of the susceptibility analysis for septic systems. Institutional, retail, and industrial facilities: The analysis determined that the potential for institutional, retail, and industrial facilities in the watershed to impair water quality is high for 12, moderate for 47, and low for 15 facilities. Figure 22 and Table 11 in this section present the results of the analysis for these facilities.

Recreational facilities: The analysis indicated that the potential for water pollution from recreational facilities in the watershed is high for 12, moderate for 23, and low for 19 facilities. Figure 23 and Table 12 at the end of this section present the results of the analysis for recreational facilities. Residential and commercial areas: The analysis determined that the potential for contaminants carried in runoff from residential and commercial areas in the watershed to impair water quality is high for seven and moderate for two areas. Figure 24 and Table 13 in this section present the results of the susceptibility analysis for residential and commercial areas. Quarry sites: The analysis found that the potential for water pollution from the eight quarry sites located in the watershed is high. Figure 25 and Table 14 in this section present the results of the susceptibility analysis for quarry sites. Shoreline erosion: The US Army Corps of Engineers (ACOE) and Iowa DNR have identified 37 priority shoreline erosion control sites at Rathbun Lake. The sites have been identified based on potential for continued erosion and sediment delivery to the lake, quality of aquatic habitat in need of protection, impact to public facilities, and feasibility of installing and maintaining erosion control practices. Figure 26 at the end of this section identifies these sites. Summary of potential point source susceptibility analysis: The analysis found that 391 possible point sources in the watershed have a relatively high potential to impair water quality in Rathbun Lake. Road and railroad intersections, shoreline erosion sites, and septic system concentration areas account for the majority of these potential point sources. At the same time, most of the wastewater treatment facilities, residential and commercial areas, and quarry sites have a high potential to impair water quality.

The analysis found that 391 possible point sources in the watershed have a relatively high potential to impair water quality in Rathbun Lake.


SECTION VI CONTD. Susceptibility Analysis for Potential Non-point Sources The susceptibility analysis for potential non-point sources compared the estimated amounts of eroded soil and chemicals carried in runoff from land used primarily for agricultural production in each of the 61 sub-watersheds in the Rathbun Lake watershed. The estimates of eroded soil and chemicals in runoff used in the analysis were obtained from the inventory of potential non-point sources described in Section V. In addition, the analysis used information collected during the inventory to evaluate the impact of activities on riparian zones in the 61 sub-watersheds as well as the potential for livestock operations in the sub-watersheds to impair water quality. The results of the susceptibility analysis for potential non-point sources of contaminants in the Rathbun Lake watershed are described below. Eroded soil from land in the watershed: The analysis determined that the relative amounts of sediment from all types of soil erosion that are carried in runoff are very high in six sub-watersheds and high in 17 sub-watersheds. The analysis indicated that sheet and rill erosion accounts for an estimated 65 percent of the sediment carried in runoff from land in the sub-watersheds and that gully erosion and streambank erosion contribute nine percent and 26 percent respectively. While the analysis found that sheet and rill erosion is the primary source of sediment, relatively significant amounts of sediment were identified from gully erosion in 31 sub-watersheds and streambank erosion in 24 sub-watersheds. Figures 27, 28, 29, 30, and 31 and Table 15 at the end of this section present the results of the susceptibility analysis for eroded soil from land in the watershed.

The relative amount of sediment from soil erosion that is carried in runoff is very high in six sub-watersheds and high in 17 sub-watersheds.

Chemicals from land in the watershed: The analysis determined that the relative amounts of sediment-bound and soluble phosphorus carried in runoff are very high in 18 and high in 24 sub-watersheds. In addition, the analysis indicated that the relative amounts of sediment-bound and soluble nitrogen carried in runoff are very high in 17 and high in 31 sub-watersheds. According to the analysis, most of the phosphorus and nitrogen carried in runoff is sediment-bound. The analysis also found that the relative amount of sediment-bound and soluble atrazine in runoff is high to very high in 28 sub-watersheds. According to the analysis, most of the atrazine carried in runoff is in soluble form. The analysis identified 12 sub-watersheds in which the amounts of both phosphorus and nitrogen carried in runoff are very high. Six of these sub-watersheds also have high to very high amounts of atrazine in the runoff. The analysis identified 27 sub-watersheds in which the amounts of both phosphorus and nitrogen in runoff are high. Nine of these sub-watersheds also have high to very high amounts of atrazine in the runoff. Figures 32, 33, 34, 35, 36, and 37 at the end of this section present the results of the susceptibility analysis for chemicals from land in the watershed.

The relative amounts of farm chemicals carried in runoff are high to very high in 15 sub-watersheds. (Photo courtesy NRCS)


SECTION VI CONTD. Impact of activities on riparian zones: The analysis found that riparian zone conditions in 13 sub-watersheds are relatively highly deteriorated. The impact of livestock use was the primary factor contributing to the degraded conditions in these riparian zones. Bank instability, channel alterations, limited natural vegetation, and reduced width also contributed to the degraded riparian zone conditions. These deteriorated riparian zones are less effective at filtering sediment and chemicals carried in runoff from adjacent land used for agricultural production and are potential sources of contaminants such as eroded soil and livestock wastes that can impair water quality. Figure 38 and Table 16 at the end of this section present the results of the susceptibility analysis for the impact of activities on riparian zones.

Deteriorated riparian zones are less effective at filtering sediment and chemicals carried in runoff from agricultural land.

Livestock grazing operations: According to the analysis, the potential for livestock operations to impair water quality in Rathbun Lake is relatively high in 15, moderate in 25, and low in 21 sub-watersheds. A total of 186 livestock operations are located in the 15 sub-watersheds with a high potential for impairing water quality. An estimated 139 of these operations rely primarily on pasture for grazing with little or no confinement of livestock. The analysis found that improved management of livestock access to riparian zones in most of these operations would help reduce any negative impact on water quality. Figure 39 and Table 17 in this section present the results of the susceptibility analysis for livestock operations.

Livestock feeding operations: As stated above, the analysis determined that the potential for livestock operations to impair water quality in Rathbun Lake is high in 15 sub-watersheds. An estimated 47 of the 186 livestock operations that are located in the 15 sub-watersheds with a high potential for impairing water quality confine livestock, for example, in lots or buildings, for at least a portion of the year. The analysis found that many of these operations would benefit from the application of practices to control runoff and improve the storage, handling, and use of livestock waste. Figure 39 and Table 17 at the end of this section present the results of the susceptibility analysis for livestock operations. Summary of potential non-point source susceptibility analysis: The analysis found that eroded soil in 23 sub-watersheds and farm chemicals in 15 sub-watersheds have a high to very high potential to impair water quality in Rathbun Lake. The analysis also found that riparian zone conditions in 13 sub-watersheds are relatively highly deteriorated and that the potential for livestock operations to impair water quality is high in 15 sub-watersheds. When considered together, the analysis determined that eroded soil and chemicals carried in runoff, deteriorated riparian zone conditions, and livestock operations in 12 sub-watersheds have a very high potential of impairing water quality in Rathbun Lake. The analysis identified an additional 15 sub-watersheds in which the combination of eroded soil, chemicals, riparian conditions, and livestock operations have a relatively high potential to impair water quality in the lake. Figure 40 and Table 18 at the end of this section present this summary of the susceptibility analysis for all potential non-point sources.

Eroded soil, chemicals, riparian conditions, and livestock operations in 12 sub-watersheds have a very high and in 15 sub-watersheds have a high potential to impair water quality in Rathbun Lake.


CLARKE

LUCAS

MONROE

DECATUR

WAYNE

APPANOOSE

RATHBUN LAKE

IOWA

Source: Chariton Valley RC&D Iowa DNR NRGIS USDA Natural Resources Conservation Service


N

5 0 5 Miles

REGIONAL LOCATION

RATHBUN LAKE WATERSHEDSusceptibility Analysis AreasSouth Central Iowa

County Boundary



Drainage

Susceptibility Analysis

Low Susceptibility

Moderate Sucecptibility

High Suceptibility


LEGEND

Figure 18

Iowa Source Water Protection Plan

Land-Use Risk PotentialLeast Risk Score Land Use Type

Risk 1 Land surrounding a well or reservoir owned by a water company

1 Permanent open space dedicated to recreation

| 1 Federal, state, municipal, or private parks| 1 Woodlands managed for forest products| 2 Field crops: pasture, hay, grains, vegetables| 2 Low-density residential (Lots larger than 2 acres)| 2 Churches, municipal offices||

3 Agricultural production (Dairy, livestock, poultry, nurseries, orchards,berries)

| 3 Golf courses, quarries| 3 Medium-density residential (Lots from 1/2 - 1 acre)||

4 Institutional uses (Schools, hospitals, nursing homes, prisons, garages, saltstorage, sewage treatment facilities)

| 4 High-density housing (Lots smaller than 1/2 acre)||

4 Commercial uses (Limited hazardous material storage, sole sewage disposal,permitted animal feeding operations)

| 5 Improperly abandoned wells in the same aquifer as the supply well|||

5 Retail commercial (Gasoline, bulk petroleum storage facilities, farmequipment, automotive, sales and services, dry cleaners, photo processor,medical arts, furniture strippers, machine shops, radiator repair, printers,fuel oil distributors)

| 5 Industrial (All forms of manufacturing and processing, research facilities)

5 Underground storage of chemicals, petroleum

GreatestRisk

5 Waste disposal (Pits, ponds, lagoons; injection wells used for waste disposal;landfills; hazardous waste treatment, storage, and disposal sites;agricultural drainage wells)

CVRCD

Table 7

CVRCD

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CLARKE

LUCAS

MONROE

DECATUR

WAYNE

APPANOOSE

RATHBUN LAKE

IOWA

N

5 0 5 Miles

REGIONAL LOCATION

RATHBUN LAKE WATERSHEDDrainage Intersections With Roads and Railroads AnalysisSouth Central Iowa

N

REGIONAL LOCATION

Source: Chariton Valley RC&D Iowa DNR NRGIS Iowa DOT Digital CAD Drawings Prepared By: Rathbun Regional Water Association

County Boundary

Bridge Analysis

Low Potential%

Moderate Potential%

High Potential%

Railroad Bridge Analysis

Moderate Potential#

High Potential#

Culvert or Other Structure Analysis

Low Potential$

Moderate Potential$

High Potential$


Railroad

Roads

Drainage (1:24000)


LEGEND

Figure 19

Table 8

Roads, Railroads, and Streams Intersection Inventory and AnalysisRathbun Lake Watershed

Bridge Intersections NumberHigh Risk Potential 53Moderate Risk Potential 101Low Risk Potential 20

Total 174

Railroad Bridge Intersections NumberHigh Risk Potential 29Moderate Risk Potential 3Low Risk Potential 0

Total 32

Culvert or Other Structure Intersections NumberHigh Risk Potential 200Moderate Risk Potential 474Low Risk Potential 152

Total 826

5 0 5 Miles

#

#

#

#

##

##

CLARKE

LUCAS

MONROE

DECATUR

WAYNE

APPANOOSE

RATHBUN LAKE

87

6 5

4

3

2

1

IOWA


N

REGIONAL LOCATION

RATHBUN LAKE WATERSHEDWastewater Treatment Facilities AnalysisSouth Central Iowa

County Boundary

Wastewater Treatment Facility Analysis

Moderate Potential#

High Potential#



Drainage


LEGEND

Figure 20

Table 9

Wastewater Treatment Facilities Inventory and AnalysisRathbun Lake Watershed

ID 24 Hour Time of Travel Score 1/4 Mile Buffer Score Land Use Score Total Score1 5 5 5 152 5 5 5 153 1 5 5 114 5 5 5 155 5 5 5 156 5 5 5 157 5 5 5 158 5 5 5 15

REGIONAL LOCATION

5 0 5 Miles

N


IOWA

CLARKE

LUCAS

MONROE

DECATUR

WAYNE

APPANOOSE89

88

87

86

8584

83

8281

8079

78 7776

75

7473

72

71

706968

6766

65

6463

62

6160

5958

5756

5554

53

5251

5049

48 4746

45 44

43

42

4140

39

3837

363534

33

32

3130

29

28

27

26

25

24

2322

21

20

1918

17

1615

14

1312

1110

98

76

5

4

32 1

RATHBUN LAKE

RATHBUN LAKE WATERSHEDPotential Septic System Concentrations AnalysisSouth Central Iowa

County Boundary



Drainage

Septic System Concentrations Analysis

Low Potential

Moderate Potential

High Potential


LEGEND

Figure 21

Table 10

Potential Septic Systems Concentrations Inventory and AnalysisRathbun Lake Watershed

ID 24 Hour Time of Travel Score 1/4 Mile Buffer Score Land Use Score Total Score Size of Area Score Modified Score1 5 5 2 12 2 142 5 5 2 12 3 153 5 5 2 12 1 134 5 5 2 12 2 145 5 5 2 12 2 146 5 5 2 12 1 137 5 5 2 12 2 148 5 5 2 12 1 139 5 5 2 12 2 14

10 5 5 2 12 1 1311 5 5 2 12 3 1512 5 5 2 12 3 1513 5 5 2 12 3 1514 5 5 2 12 1 1315 5 5 2 12 2 1416 5 5 2 12 1 1317 5 5 2 12 3 1518 5 5 2 12 2 1419 5 5 2 12 3 1520 5 5 2 12 2 1421 5 5 2 12 2 1422 5 5 2 12 2 1423 5 5 2 12 4 1624 5 5 2 12 2 1425 5 5 2 12 3 1526 5 5 2 12 2 1427 5 5 2 12 1 1328 5 5 2 12 3 1529 5 5 2 12 4 1630 5 5 2 12 1 1331 5 5 2 12 1 1332 5 5 2 12 2 1433 1 5 2 8 1 9

Table 10

ID 24 Hour Time of Travel Score 1/4 Mile Buffer Score Land Use Score Total Score Size of Area Score Modified Score34 1 5 2 8 1 935 5 5 2 12 2 1436 1 5 2 8 1 937 5 5 2 12 3 1538 5 5 2 12 4 1639 5 5 2 12 2 1440 5 5 2 12 1 1341 5 5 2 12 1 1342 5 5 2 12 1 1343 5 5 2 12 2 1444 5 5 2 12 3 1545 5 5 2 12 4 1646 5 5 2 12 1 1347 5 5 2 12 3 1548 5 5 2 12 2 1449 5 5 2 12 1 1350 5 5 2 12 2 1451 5 5 2 12 1 1352 5 5 2 12 2 1453 5 5 2 12 2 1454 5 5 2 12 2 1455 5 5 2 12 2 1456 5 5 2 12 2 1457 5 5 2 12 2 1458 5 5 2 12 2 1459 5 5 2 12 1 1360 5 5 2 12 2 1461 5 5 2 12 5 1762 1 5 2 8 1 963 1 5 2 8 1 964 5 5 2 12 2 1465 1 5 2 8 4 1266 1 5 2 8 2 1067 1 5 2 8 2 1068 5 5 2 12 2 1469 5 5 2 12 1 13

Table 10

ID 24 Hour Time of Travel Score 1/4 Mile Buffer Score Land Use Score Total Score Size of Area Score Modified Score70 5 5 2 12 4 1671 5 5 2 12 2 1472 5 5 2 12 1 1373 5 5 2 12 3 1574 5 5 2 12 2 1475 5 5 2 12 3 1576 5 5 2 12 1 1377 5 5 2 12 1 1378 5 5 2 12 4 1679 5 5 2 12 4 1680 5 5 2 12 3 1581 5 5 2 12 2 1482 5 5 2 12 2 1483 5 5 2 12 3 1584 5 5 2 12 2 1485 5 5 2 12 4 1686 1 5 2 8 5 1387 1 5 2 8 5 1388 5 5 2 12 5 1789 5 5 2 12 5 17

#

##

##

#

##

#

#

##

#

##

#

#

#

#

##

#

#

#

#

###

#

####

#

#

##

#

#

####

#

#

#

#

#

# #

#

#

#

#

#

#

########

#

##

##

#

##

#

#

Derby

Le RoyHumeston

Millerton

Corydon

Chariton

Russell

Allerton

Promise City

RATHBUN LAKE

CLARKE

LUCAS

MONROE

DECATUR

WAYNE

APPANOOSE36

75

74

7372

71

7069

6867

66

65 64

636261

60

5958

57

56

55

54

53

52

5150

49

48

47

46

45

42,43,44

41

40

3938

35

34

3332

31

3029

28 27

26

25

24

2322

21

19

18

17

16

37

15

14

13

1211

10

9

8 7

6

54

32

1

IOWA

Source: Chariton Valley RC&D Iowa DNR NRGIS US Bureau of Census Tiger Data US Army Corps of Engineers Wayne County SWCD EPA Basins Data Prepared By: Rathbun Regional Water Association

N

5 0 5 Miles

REGIONAL LOCATION

RATHBUN LAKE WATERSHEDInstitutional, Retail, and Industrial Facilities AnalysisSouth Central Iowa

County Boundary

Facilities Analysis

Low Potential#

Moderate Potential#

High Potential#



Drainage (1:24000)

City or Town


LEGEND

Figure 22

Table 11

Institutional, Retail, and Industrial Facilities Inventory and AnalysisRathbun Lake Watershed

ID Type Land Use Score Type 24 Hour Time of Travel Score 1/4 Mile Buffer Score Land Use Score Total Score1 Agricultural Commercial 5 1 4 102 Agricultural Commercial 1 5 4 103 Agricultural Commercial 5 1 4 104 Agricultural Commercial 5 5 4 145 Agricultural Commercial 5 1 4 106 Agricultural Commercial 5 1 4 107 Pesticide Commercial 5 1 4 108 Agricultural Commercial 5 1 4 109 Agricultural Commercial 5 1 4 10

10 Agricultural Commercial 5 1 4 1011 Agricultural Commercial 1 1 4 612 Agricultural Commercial 1 1 4 613 County Institutional 5 5 4 1414 County Institutional 5 1 4 1015 Pesticide Commercial 5 1 4 1016 Airport Commercial 5 5 4 1417 Airport Commercial 5 1 4 1018 Airport Commercial 1 5 4 1019 Airport Commercial 5 5 4 1421 Airport Commercial 5 5 4 1422 Airport Commercial 5 1 4 1023 Hospital Institutional 5 1 4 1024 UST Underground St. Tank 5 1 5 1125 UST Underground St. Tank 5 1 5 1126 UST Underground St. Tank 5 5 5 1527 UST Underground St. Tank 5 1 5 1128 UST Underground St. Tank 5 1 5 1129 UST Underground St. Tank 5 1 5 1130 UST Underground St. Tank 5 1 5 1131 UST Underground St. Tank 5 1 5 1132 UST Underground St. Tank 5 1 5 1133 UST Underground St. Tank 5 1 5 1134 UST Underground St. Tank 5 5 5 1535 UST Underground St. Tank 5 1 5 1136 Industrial Industrial 5 1 5 1137 Agricultural Commercial 5 5 4 1438 Educational Institutional 5 5 4 14

Table 11

ID Type Land Use Score Type 24 Hour Time of Travel Score 1/4 Mile Buffer Score Land Use Score Total Score39 Educational Institutional 5 5 4 1440 Educational Institutional 5 1 4 1041 Educational Institutional 5 1 4 1042 Educational Institutional 5 1 4 1043 Educational Institutional 5 1 4 1044 Educational Institutional 5 1 4 1045 Churches Churches 5 5 2 1246 Churches Churches 5 5 2 1247 Churches Churches 5 5 2 1248 Institutional Institutional 5 1 4 1049 Churches Churches 5 1 2 850 Churches Churches 5 1 2 851 Churches Churches 5 1 2 852 Churches Churches 5 1 2 853 Churches Churches 5 5 2 1254 Churches Churches 5 5 2 1255 Commercial Commercial 5 1 4 1056 Churches Churches 1 1 2 457 Churches Churches 5 5 2 1258 Institutional Institutional 5 1 4 1059 Churches Churches 5 1 2 860 Churches Churches 5 1 2 861 Institutional Institutional 5 1 4 1062 Institutional Institutional 5 1 4 1063 Commercial Commercial 5 1 4 1064 Institutional Institutional 5 1 4 1065 Retail Commercial Retail Commercial 5 5 5 1566 Churches Churches 5 1 2 867 Educational Institutional 5 1 4 1068 Educational Institutional 5 5 4 1469 Educational Institutional 1 1 4 670 Churches Churches 1 1 2 471 Churches Churches 1 1 2 472 Churches Churches 5 5 2 1273 Churches Churches 5 1 2 874 Churches Churches 5 5 2 1275 Churches Churches 5 1 2 8

REGIONAL LOCATION

5 0 5 Miles

N


IOWA

##

#

#

##

###

##

#

####

##

##

# #

######

##

#

##

##

#

##

###

##

###

##

#

#

#

#

#

#

CLARKE

LUCAS

MONROE

DECATUR

WAYNE

APPANOOSE

54

53

52

18

25

51

5049

4847

46

45 44

43 42

4140

39

38

37 36 35

34

33

323130 29

28272624

23222120

1917

16 151413

12

1110

9 87

65

4

32

1

RATHBUN LAKE WATERSHEDRecreational Facilities AnalysisSouth Central Iowa

County Boundary

Recreational Facilities Analysis

Low Potential#

Moderate Potential#

High Potential#



Drainage (1:24000)


LEGEND

Figure 23

Table 12

Recreational Facilities Inventory and AnalysisRathbun Lake Watershed

ID Type 24 Hour Time of Travel Score 1/4 Mile Buffer Score Land Use Score Total Score1 Boat Ramp 5 5 2 122 Boat Ramp 5 5 2 123 Boat Ramp 5 5 2 124 Boat Ramp 5 5 2 125 Boat Ramp 5 5 2 126 Boat Ramp 5 5 2 127 Boat Ramp 5 5 2 128 Boat Ramp 5 5 2 129 Boat Ramp 5 5 2 12

10 Boat Ramp 5 5 2 1211 Boat Ramp 5 5 2 1212 Boat Ramp 5 5 2 1213 Campground 5 5 1 1114 Campground 5 5 1 1115 Campground 5 5 1 1116 Campground 5 5 1 1117 Campground 5 5 1 1119 Campground 5 5 1 1120 Campground 5 5 1 1121 Campground 5 5 1 1122 Campground 5 5 1 1123 Campground 5 5 1 1124 Boat Ramp 5 5 2 1226 Marina 5 5 5 1527 Campground 5 5 1 1128 Campground 5 5 1 1129 Campground 5 5 1 1130 Campground 5 5 1 1131 Boat Ramp 5 5 2 1232 Marina 5 5 5 1533 Boat Ramp 5 5 2 1234 Boat Ramp 5 5 2 1235 Campground 5 5 1 1136 Lagoon 5 5 5 1537 Lagoon 5 5 5 1538 Lagoon 5 5 5 1539 Lagoon 5 5 5 1540 Lagoon 5 5 5 1541 Lagoon 5 5 5 1542 Lagoon 5 5 5 1543 Lagoon 5 5 5 1544 Lagoon 5 5 5 1545 Lagoon 5 5 5 1546 Boat Ramp 5 5 2 1247 Boat Ramp 5 5 2 1248 Boat Ramp 5 5 2 1249 Boat Ramp 5 5 2 1250 Campground 5 5 1 1151 Campground 5 5 1 1125 Boat Ramp 5 5 2 1218 Boat Ramp 1 5 2 852 Golf Course 5 5 3 1353 Golf Course 1 5 3 954 Golf Course 5 5 3 13

REGIONAL LOCATION

5 0 5 Miles

N


IOWA

Derby

Le RoyHumeston

Millerton

Corydon

Chariton

Russell

Allerton

Promise City

RATHBUN LAKE

CLARKE

LUCAS

MONROE

DECATUR

WAYNE

APPANOOSE

RATHBUN LAKE WATERSHEDResidential and Commercial Areas AnalysisSouth Central Iowa

Figure 24

County Boundary



Drainage (1:24000)

Runoff from Residential and Commercial Areas Analysis

Moderate Potential

High Potential


LEGEND

Table 13

Runoff From Residential and Commercial Areas Inventory and AnalysisRathbun Lake Watershed

ID Place Name 24 Hour Time of Travel Score 1/4 Mile Buffer Score Land Use Score Total Score1 Derby 1 5 4 102 Le Roy 1 5 4 103 Humeston 5 5 4 144 Millerton 5 5 4 145 Corydon 5 5 4 146 Chariton 5 5 4 147 Russell 5 5 4 148 Allerton 5 5 4 149 Promise City 5 5 4 14

1

2

3

45

6

78

CLARKE

LUCAS

MONROE

DECATUR

WAYNE

APPANOOSE

RATHBUN LAKE

IOWA


N

5 0 5 Miles

REGIONAL LOCATION

RATHBUN LAKE WATERSHEDQuarry Sites AnalysisSouth Central Iowa

County Boundary



Drainage (1:24000)

Quarry Sites Analysis

High Potential


LEGEND

Figure 25

Table 14

Quarry Sites Inventory and AnalysisRathbun Lake Watershed

ID 24 Hour Time of Travel Score 1/4 Mile Buffer Score Land Use Score Total Score1 5 5 3 132 5 5 3 133 5 5 3 134 5 5 3 135 5 5 3 136 5 5 3 137 5 5 3 138 5 5 3 13

%[%[

%[ %[%[%[

%[%[

%[%[

%[%[

%[%[

%[

%[%[%[%[%[%[%[

%[

%[%[

%[

%[%[

%[%[

%[%[%[

%[%[%[

%[

Rathbun Lake

WAYNE

LUCAS MONROE

APPANOOSE

County Boundaries

Priority Shoreline Erosion Control Sites%[

Rathbun Lake (904 Ft. Pool Elevation)

LEGEND

1 0 1 Miles

Source: Chariton Valley RC&D Iowa DNR Fisheries Bureau, Larry R. Mitzner US Army Corps of Engineers Iowa DNR NRGIS


N

Figure 26

IOWA

Shoreline Erosion AnalysisRathbun LakeSouth Central Iowa

10280201040210

10280201040200

1028020104022010280201040160 10280201050010

1028020104026010280201040080

10280201040100 10280201050020

10280201040250

10280201040230

10280201040090

10280201040290

10280201040020

1028020104017010280201040010

10280201040070

1028020107001010280201040190

1028020104012010280201040110

1028020107002010280201040060

10280201040270

102802010402401028020107003010280201040280 10280201070040

10280201040050 10280201040150

1028020104013010280201040040

10280201070050

10280201040140

10280201060140

10280201040180

10280201060010

1028020106021010280201060120

10280201040030

10280201060250

10280201060230

10280201060080

10280201060070

10280201060030

10280201060200

10280201060240

10280201060090 10280201060190

10280201060130

10280201060180 10280201060220

1028020106004010280201060020

10280201060110

10280201060100 10280201060170

10280201060060 10280201060160

10280201060050

10280201060150

N

1 0 1 2 3 4 5 Miles

IOWA

Source: Iowa State UniversityChariton Valley RC&DWayne County SWCD

Prepared By:Rathbun Regional Water Association

Estimated Delivered Streambank Erosion3 - 160 Acre Plot AverageRathbun Lake Subwatersheds

County Boundary

Sediment Delivery (Tons/160 Acres)

0 - 24.16

24.16 - 44.08

44.08 - 56.06

56.06 - 77.29

77.29 - 96.92

LEGEND

Figure 27

CLARKE

LUCAS

MONROE

WAYNE

APPANOOSE

DECATUR

10280201040210

10280201040200

1028020104022010280201040160 10280201050010

1028020104026010280201040080

10280201040100 10280201050020

10280201040250

10280201040230

10280201040090

10280201040290

10280201040020

1028020104017010280201040010

10280201040070

1028020107001010280201040190

1028020104012010280201040110

1028020107002010280201040060

10280201040270

102802010402401028020107003010280201040280 10280201070040

10280201040050 10280201040150

1028020104013010280201040040

10280201070050

10280201040140

10280201060140

10280201040180

10280201060010

1028020106021010280201060120

10280201040030

10280201060250

10280201060230

10280201060080

10280201060070

10280201060030

10280201060200

10280201060240

10280201060090 10280201060190

10280201060130

10280201060180 10280201060220

1028020106004010280201060020

10280201060110

10280201060100 10280201060170

10280201060060 10280201060160

10280201060050

10280201060150

N

1 0 1 2 3 4 5 Miles

IOWA

Source: Iowa State UniversityChariton Valley RC&DWayne County SWCD

Prepared By:Rathbun Regional Water Association

Estimated DeliveredGully Erosion3 - 160 Acre Plot AverageRathbun Lake Subwatersheds

County Boundary

Sediment Delivery (Tons/160 Acres)

3.71 - 8.36

8.36 - 13.34

13.34 - 16.05

16.05 - 18.48

18.48 - 22.75

LEGEND

Figure 28

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