03-11596. Glen Ellen Subwatershed Supplemental Watershed Plan and Environmental Assessment Number 1, Woodbury County, 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 Glen Ellen Subwatershed Supplemental Plan Number 1, Woodbury County, 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 prevent the loss of life from catastrophic dam failures and to maintain the gully stabilization and flood protection functions of three dams that were constructed in 1963.

The project actions include relocating three houses from the breach inundation area of Site (dam) 2-2, rehabilitating both this site and Site 3-1 to low hazard class, and rehabilitating Site 3-2 to high hazard class. This rehabilitation will provide a new 50 year life to the three sites to continue their original gully stabilization and flood prevention functions. Future residential and commercial development in the breach inundation areas below Sites 2-2 and 3-1 will be restricted by county zoning ordinance.

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 Glen Ellen Subwatershed Supplemental Watershed Plan and Environmental Assessment Number 1 Woodbury County, IA

Introduction

The supplemental watershed plan and environmental assessment describes the recommended alternative and other alternatives to prevent the loss of life from catastrophic dam failures within the Glen Ellen Subwatershed of the Little Sioux River Flood Prevention Project. Rehabilitating Sites 2-2, 3-1, and 3-2 also provides continued flood protection and gull stabilization.

The rehabilitation of these three dams is necessary because four houses occupied by eleven people have been built in the breach inundation areas since the dams were constructed in 1963. Sites 2-2 and 3-2 have been reclassified as high hazard by NRCS because of the possibility of loss of life should the dams fail.

The dams were installed to control severe gully erosion and reduce flooding. The structures receive drainage from areas of 194 to 350 acres.

The Glen Ellen Subwatershed project was approved in 1963 under the authority of the Flood Control Act of 1944 (Pub. L. 534, 78th Congress, 2nd Session).

This rehabilitation action is being planned and will be implemented under the Watershed Protection and Flood Prevention Act Public Law 83-566 as amended by Public Law 106-472. It is being planned and is in compliance with all National Environmental Policy Act (NEPA) and the National Historic Preservation Act of 1966 as amended (NHPA) provisions. The policies and procedures of the Watershed Protection and Flood Prevention Act, Public Law 83-566 as amended (16 U.S.C. 1001 et seq.) are being utilized for the planning and implementation of this project.

Glen Ellen 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. The proposed rehabilitation actions are authorized in accordance with the original federal authorities as amended by the Small Watershed Rehabilitation Amendments of 2000.

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 conjunction with local, state and federal agencies as well as interested organizations and individuals. Data developed during this 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, IA 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

Rehabilitation of site 2-2 will consist of relocating three houses currently located in the breach inundation area and rehabilitating the dam to low hazard class criteria for a new 50-year life. Rehabilitating Site 2-2 includes replacing the inlet of the principal spillway, raising the crest of the principal spillway one foot, and excavating about 1.5 acre-feet of sediment from the existing pool. The three houses will be purchased and the three homeowners will be provided relocation assistance in accordance with the Federal Uniform Relocation Assistance and Real Property Acquisitions Policies Act (Public Law 91-646). The Woodbury County Zoning Administrator will carry out the relocation process.

Site 3-1, which is in series upstream of Site 3-2, will be rehabilitated for a new 50-year life using high hazard class hydrology but will remain a low hazard class dam. Site 3-1 will be rehabilitated by replacing the corrugated metal pipe with concrete pipe, raising the principal spillway elevation one foot, and raising the top of dam 6.2 feet. About 3.5 acre-feet of sediment will be removed from the existing permanent pool. The auxiliary spillway will be widened an additional 40 feet.

Site 3-2 will be rehabilitated to high hazard class criteria by replacing the corrugated metal pipe with concrete pipe, raising the principal spillway elevation one foot, and raising the top of dam 5.5 feet. The auxiliary spillway will be widened an additional 40 feet. The rehabilitation of this site eliminates the threat to loss of life at one house from catastrophic dam failure.

Future residential and commercial development in the breach inundation areas of Sites 2-2 and 3-1 will be restricted. Downstream of Site 2-2 the Woodbury County Board of Supervisors will take fee title to the three lots following relocation of the houses. The sponsors may also add deed restrictions prohibiting development or use county zoning ordinances for these three lots. The balance of the breach inundation area beyond the acquired properties will be restricted by using county zoning ordinances. Restrictions will be enacted prior to any rehabilitation construction. County zoning ordinances will prohibit development in the upstream areas of each site, as defined from principal spillway elevation to an elevation of six feet above designed top of dam.

Effects of the Recommended Actions

• Threats to loss of life from catastrophic breaches and storm events are eliminated at Sites 2-2 and 3-2. Eleven people in four houses are protected.
• There are no cultural resources in the area of potential effect. Construction discoveries will be handled in accordance with NRCS General Manual, Section 420, part 401.
• Gully erosion remains controlled at all 3 sites. Sheet and rill erosion as well as ephemeral cropland gully erosion remains controlled.
• Flood control benefits are maintained for another 50 years on 366 acres of agricultural land.
• Sediment delivered to all three sites is trapped and not delivered to Farmers Drainage Ditch and Little Sioux River system. A total of five acre-feet of sediment will be removed during construction from Sites 2-2 and 3-1. This sediment will be used to top dress Site 3-1's borrow area and the area where the three houses are removed. A plan to remove, utilize, and stabilize the sediment by controlling erosion and runoff will be developed with consultation with the Iowa Department of Natural Resources.
• There are wetlands associated with the three pools. Raising the spillway elevation will deepen water over some wetlands. This deeper water will not eliminate any wetlands but it will change their classification to another type. The expanded pools will create new wetlands.
• No Threatened and Endangered species are present at the existing sites.
• Raising the principal spillway elevations of the structures will inundate an additional 1.5 acres of low value grassland habitat. Increasing the fill heights of the structures will impact 1.6 acres of low value grassland habitat. The area downstream of Site 2-2, where the three houses are removed, will be seeded to a mixed prairie seeding increasing this habitat type by 3.3 acres in the subwatershed. The impacts to grassland habitat have been determined to be not significant, therefore formal mitigation will not be required.
• Continued flood protection on 110 acres maintains the land as prime farmland.
• Soil erosion, especially gully erosion, will be controlled in this portion of the Loess Hills which are a nationally recognized and unique natural resource.
• Construction will result in temporary generation of dust and emissions from internal combustion engines.
• Local fishing opportunity will be maintained.
• No other significant adverse environmental impacts will occur from installation of project features.
• There are no existing or anticipated public controversies associated with this proposed action.

Alternative Actions

Other alternative actions were considered in the planning process but were rejected. The plan is the most acceptable to local residents and local project sponsors. The plan eliminates threats to loss of life from catastrophic breaches and storm events. The original project purposes of gully control and flood prevention are maintained. The plan is not the National Economic Development (NED) plan. An exception to selecting the NED plan was granted by the Chief of the NRCS on April 21, 2003.

Consultation and Public participation

The Woodbury County SWCD and the Woodbury County Board of Supervisors discussed and conducted official actions to support the rehabilitation of Sites 2-2, 3-1, and 3-2 at their respective public meetings in 2001. The sponsors indicated a clear interest in rehabilitating these three Glen Ellen sites. Representatives of the sponsors, the Woodbury County Secondary Road Department, and NRCS met on February 12, 2001, to discuss the dam hazard class changes and possible alternatives to resolve the situation. The road department agreed to investigate relocating a segment to Glen Ellen Road as a component of raising the dam at Site 2-2. A follow up meeting was held on June 13, 2001.

Iowa NRCS conducted a state level informational meeting on the Watershed Rehabilitation Program on October 30, 2001. More than 60 letters of invitation were mailed to state level representatives of state and federal agencies, tribes, conservation groups, agricultural groups and others. Discussion of the Glen Ellen project was included at the meeting.

Two public meetings were held in Sergeant Bluff on November 29, 2001 to inform the public about the rehabilitation needs on Sites 2-2, 3-1, and 3-2 in addition to gaining public input and support for the planning process. The three homeowners downstream of Site 2-2 voiced strong support for voluntary relocation of their houses.

Individual meetings were held with the three homeowners downstream, of Site 2-2 on April 22, 2002. The homeowners confirmed their continued strong support for relocation and each indicated their intent to participate in relocation. The Woodbury County SWCD voted on April 16, 2002 to support the relocation alternative. On April 23, 2002, the Woodbury County Board of Supervisors voted to support the project by providing extensive in-kind services from their Planning and Zoning Department, Secondary Roads Department, and County Conservation Board.

Twenty Indian tribal contacts and two local historical societies were notified of this intended action in accordance with 36 CFR part 800. They were consulted about their knowledge of historical properties in the project area. The only response received during the comment period was from the Prairie Band Potawatomi Nation who stated they were unaware of cultural resources related to the tribe in the project area.

The Glen Ellen Subwatershed Draft Supplemental Watershed Plan and Environmental Assessment Number 1 was sent to 40 public agencies and private groups interested in natural resource issues. Six letters of comment were received during the 45-day review period ending on February 24, 2003.

Changes were made to the plan in response to the Woodbury County Zoning Administrator's comment on the use of deed restrictions in addition to zoning to prevent redevelopment on three lots downstream from Site 2-2. Clarifications were made to reflect impacts on wetlands in response to comments received from the Army Corps of Engineers.

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 Glen Ellen Subwatershed Draft Supplemental Watershed Plan and Environmental Assessment Number 1 is not required.

Dated: April 30, 2003.

Dennis J. Pate,

Assistant State Conservationist—Technology.