01-10813. Iowa Watershed Rehabilitation Pilot Project Plan, Monona and Mills Counties, IA

AGENCY:

Natural Resources Conservation Service, USDA.

ACTION:

Notice of finding of no significant impact.

SUMMARY:

Pursuant to Section 102(2)(c) of the National Environmental Policy Act of 1969; the Council on Environmental Quality Regulations (40 CFR part 1500); and the Natural Resources Conservation Service Regulations (7 CFR part 650); the Natural Resources Conservation Service, U.S. Department of Agriculture, gives notice that an environmental impact statement is not being prepared for the Iowa Watershed Rehabilitation Pilot Project Plan, Monona and Mills Counties, Iowa.

FOR FURTHER INFORMATION CONTACT:

Leroy Brown, State Conservationist, Natural Resources Conservation Service, 210 Walnut Street, 693 Federal Building, Des Moines, IA 50309-2180.

SUPPLEMENTARY INFORMATION:

The environmental assessment of this federally assisted action indicates that the project will not cause significant impacts on the environment. As a result of these findings, Leroy Brown, State Conservationist, has determined that the preparation and review of an environmental impact statement are not needed for this project.

The project purpose is to develop procedures and demonstrate actions that may be used to implement a statewide watershed rehabilitation program in Iowa. To accomplish this, two aging watershed structures will be rehabilitated as a pilot project to demonstrate methods and develop public support for the rehabilitation program. These actions will restore these two structures so they will continue to function for 50 years.

The project actions include the reshaping of the road ditch in a road right-of-way, modifying the auxiliary spillway to lower its elevation by three feet and replacement of a principal spillway outlet on a structure in Mills County that threatens motorist safety on U.S. Highway 34 in case of a dam breach. The project actions in Monona County include renovation of structure fill and spillway, a conservation easement to convert existing 49 acres of cropland to native grass and forbs, approximately eight sediment and water control basins, 6.8 acres of waterway, pasture renovation plantings on 60 acres, and one livestock watering system.

The Plan and Environmental Assessment has been forwarded to the Environmental Protection Agency and to various Federal, State, and local agencies and to interested parties. A limited number of copies of the plan and environmental assessment are available to fill single copy requests at the above address. Basic data developed during the environmental assessment are on file and may be viewed by contacting Leroy Brown.

No administrative action will be taken until 30 days after the date of this publication in the Federal Register.

Finding of No Significant Impact for the Iowa Watershed Rehabilitation Pilot Project, Lawson Creek and Pony Creek Watersheds, Monona and Mills Counties, Iowa

Introduction

The proposed plan is for an Iowa Watershed Rehabilitation Pilot Project to address aging and impaired watershed structures in the State of Iowa. Two watersheds were selected for the pilot project. One structure in each watershed was chosen for use in the pilot project.

Lawson site 1-1 is an earthfill structure that was installed in 1970 to control severe gully erosion and reduce flooding. The structure receives runoff from 258 acres of agricultural land and originally had a permanent pool of 1.3 acres. The structure prematurely filled with sediment due to extreme actions of a previous private landowner. The structure is in danger of failing and a major gully problem will reform.

Pony Creek site 31 was installed in 1963 to control severe gully erosion and reduce flooding. The earthfill structure receives drainage from 270 acres of agricultural land and has a permanent pool of 14 acres. U.S. Highway 34 was relocated below the structure in 1974. This places about 8000 motor vehicles daily within the potential dam breach area. Hydraulic routings indicate that the breach of the structure would put water about two feet deep across the highway.

These two structures were chosen because they are representative of the types of problems that will be encountered in other watersheds when a state wide Watershed Rehabilitation Program is implemented.

Lawson Creek Watershed was a federally assisted action authorized and installed under Public Law 78-534, The Flood Control Act as part of the Little Sioux River Flood Prevention Project. Pony Creek watershed was a federally assisted action authorized and installed under Public law 83-566, The Watershed Protection and Flood Prevention Act. The proposed rehabilitation actions to remedy problems with the existing structural components at Site 1-1 in Lawson Creek Watershed and Site 31 in Pony Creek Watershed are authorized in accordance with the original federal authorities as amended by the Small Watershed Rehabilitation Amendments of 2000, and the Soil and Water Conservation, Soil Conservation and Domestic Allotment Act of 1936, as amended, Public Law 74-46, 16 U.S.C. 590 a-f (CFDA No. 10.902). An environmental assessment was undertaken by the Natural Resources Conservation Service (NRCS) in conjunction with the development of this rehabilitation plan. This assessment was undertaken in consultation with local, state and federal agencies as well as interested organizations and individuals. Data developed during assessment and copies of the rehabilitation plan are available for public review at the following location: Natural Resources Conservation Service, 210 Walnut Street, 693 Federal Building, Des Moines, Iowa 50309-2180.

An Environmental Impact Statement (EIS) was prepared for the Little Sioux Watershed Flood Prevention Project in 1976. The EIS discusses the effects of installing flood prevention and grade stabilization dams and land treatment practices.

Recommended Action

Proposed actions for Site 1-1 in Lawson Creek Watershed are:

1. Raising the existing structure height by about 15 feet.

2. Installing a new principal spillway couduit.

3. Securing a conversation easement on 49 acres above the existing pool area in perpetuity.

4. Converting the land use from cropland to native grass and forbs within the conservation easement area.

5. Installing about eight water and sediment control basins to prevent gully erosion and trap sediment.

6. Establishing 6.8 acres of grassed waterway to control erosion in drainage ways.

7. Planting improved grass mixture on 60 acres of existing pastureland to improve soil cover.

8. Installing one livestock watering system.

Proposed actions for Site 31 in Pony Creek Watershed are:

1. Modifying a constructed earth block in the highway road ditch below the structure in the right-of-way of U.S. Highway 34. The man made block would be lowered about two feet for a distance of about 50 feet.

2. Replacing the existing corrugated metal pipe principal spillway.

3. The auxiliary spillway will be modified to lower its' elevation by about three feet.

Effects of the Recommended Actions

Lawson Creek Watershed

The actions in the proposed plan for Lawson Creek Watershed will control gully erosion for 50 years at Site 1-1, reduce sheet, rill and ephemeral cropland gully erosion in the watershed above the site, reduce delivery of sediment both to the structure site and the Maple River, provide a source of water for minnow species in the structure pool, and reduce downstream peak flows.

There are three cultural resource sites recorded in the area. None are in the area of potential effect. Following its procedures, NRCS surveyed the area of potential effect and no sites were identified. Construction discoveries will be handled in accordance with NRCS General Manual, Section 420, Part 401.

The Loess Hills are a nationally significant natural area. The installation of the project measures will prevent gully damages to this portion of the Loess Hills. The planting of native vegetation as per Iowa NRCS specifications for restoration of rare and declining habitats on the 49 acre easement area will help restore native prairie vegetation to this portion of the Loess Hills.

The project will convert 49 acres of cropland to a diverse mixture of native grasses and forbs. This will add diversity and improve wildlife habitat on these 49 acres and within the watershed. Any incidental or unavoidable impacts to woody vegetation or other significant wildlife habitat types will be quantified prior to construction and any losses will be replaced through mitigation.

No threatened or endangered species are recorded in the area. No critical habitat for any species is present in the proposed project area.

There are no wetlands, prime farmland or other unique or protected land resources that will be negatively impacted to the proposed actions.

No other significant adverse environmental impacts will occur from installation of project features.

There is no existing or anticipated public controversy associated with this proposed action.

The effects of the recommended actions in Lawson Watershed are consistent with the Environmental Impact Statement prepared for the Little Sioux River Watershed Flood Prevention Project.

Pony Creek Watershed

The actions in the proposed plan for Pony Creek Watershed Site 31 will allow the structure to continue to control gully erosion, prevent any downstream sedimentation, and prevent a flood hazard to motorists on U.S. Highway 34 from a dam breach failure.

There are no significant cultural resources identified within the work area for the replacement of the existing principal spillway outlet. No new earthfill will be required.

The deepening of the block in the road ditch will affect previously disturbed soil material except for the south slope where a small area of undisturbed hillside will be disturbed. This small undisturbed area has been archaeologically surveyed and contains no cultural resources. The modification of the auxiliary spillway is in an area previously disturbed and will not affect deposits that could contain cultural resources.

If a construction discovery is made, the NRCS will take action as prescribed in the NRCS General Manual, Section 420, Part 401.

There will be no impacts to any threatened or endangered species.

No wildlife or fisheries habitats will be adversely impacted.

There will be no impacts to the Loess Hills, a nationally significant natural area.

There are no wetlands, prime farmland, agricultural land, or other natural or unique land resources that will be impacted by the actions in the proposed plan.

There will be a minor, short term adverse impact to recreational use of the Mills County Conservation Board park in which the structure is located while the new outlet pipe is being installed. The pool will be drawn down by about six feet while the new pipe is installed. This will expose some unsightly shoreline conditions and may have a minor impact on use of the pool by shoreline anglers. The project will be done quickly and all efforts will be made to limit the duration and severity of such disruptions in recreational use. No new earthfill will be required.

No other significant adverse environmental impacts will occur from installation of project features.

There is no existing or anticipated public controversy associated with this proposed action.

Alternative Actions

Other alternative actions were considered in the planning process but were rejected. The recommended alternatives for both watersheds that are included in the proposed plan, are both the most practical and lowest cost means of accomplishing the rehabilitation of the structures so that they continue to provide the original benefits for which they were constructed. These actions meet the sponsors objectives and goals, provide environmental benefits, cause no significant adverse environmental impacts, and cause no public controversy.

Consultation and Public Participation

Lawson Creek Watershed

The Monona County Soil and Water Conservation District (SWCD) has discussed the plan for Lawson Creek Watershed Site 1-1 at their regular public meetings.

The one landowner involved with Site 1-1 rehabilitation plan, conservation easement and land treatment measures has been involved with the development of this plan.

Twenty Indian tribes and three local historical societies were notified of this intended action and consulted about their knowledge of historical properties in the project area.

Only one response was received from one of the Indian tribes stating they were unaware of any cultural resources associated with the project area.

Inter-agency consultation and public participation to date have shown no unresolved conflicts with implementing this selected plan action in the Lawson Creek Watershed.

Pony Creek Watershed

The Mills County Soil and Water Conservation District (SWCD) has reviewed the plan for Pony Creek Watershed Site 31 at a public meeting.

The Mills County Conservation Board and the Iowa Department of Transportation have been involved with the development of this plan.

Twenty Indian tribes and three local historical societies were notified of this intended action and consulted about their knowledge of historical properties in the project area. Only one response was received from one of the Indian tribes stating they were unaware of any cultural resources associated with the project area. A cultural resource field investigation did not indicate the presence of cultural resources.

Inter-agency consultation and public participation to date have shown no unresolved conflicts with implementing this selected plan action in the Pony Creek Watershed.

Conclusion

The Environmental Assessment summarized above indicates that this Federal action will not cause significant impacts on the environment. Therefore, based on the above findings, I have determined that an environmental impact statement for the Iowa Watershed Rehabilitation Pilot Project is not required.

Dated: April 2, 2001.

Leroy Brown,

State Conservationist.