E6-12349. Construction in the Matanuska River of Spur Dike #5, at Circleview Estates, Palmer, AK

AGENCY:

Natural Resources Conservation Service, USDA.

ACTION:

Notice of a 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 Guidelines (40 CFR part 1500); and the Natural Resources Conservation Service (formerly the Soil Conservation Service) Guidelines (7 CFR part 650); the Natural Resources Conservation Service, U.S. Department of Agriculture, Robert Jones, State Conservationist, finds that neither the proposed action nor any of the alternatives is a major federal action significantly affecting the quality of the human environment, and determine that an environmental impact statement is not needed for the Construction in the Matanuska River of Spur Dike #5, at Circleview Estates, Palmer, AK.

FOR FURTHER INFORMATION CONTACT:

Mr. Robert Jones, State Conservationist, Natural Resources Conservation Service, Alaska State Office, 800 West Evergreen Avenue, Suite 100, Palmer, AK 99645-6539; Phone: [phone]; Fax: [phone].

SUPPLEMENTARY INFORMATION:

The environmental assessment of this Federally assisted action indicates that the project will not cause significant local, regional, or national impacts on the environment. As a result of these findings, the preparation and review of an environmental impact statement are not needed for this project.

The Matanuska River is a glacially fed river system with highly braided channels. Severe bank erosion in the Circle View Estates area has been addressed previously through the installation of rock and earthen spur dikes. Erosion has continued downstream of the dikes, threatening adjacent bank and personal property (homes, buildings, appurtenances) and public infrastructure. The purpose of the project is to protect river bank, private homes and public infrastructure from loss to the erosive forces of the river at this subdivision site.

The preferred alternative is to install a barb-head spur dike, having river-directing flow features, which is believed to be potentially more fish-friendly than the previous adjacent dike designs. Completion of the project will reduce the risk of personal property loss, extend downstream protection of the existing four dikes, reduce emergency requests and response (as well as associated capital expenditures) by local government units, reduce potential harm or loss of human life, and protect public infrastructure in the area of influence of the dikes protection.

The Notice of a Finding of No Significant Impact (FONSI) has been forwarded to the Environmental Protection Agency and other interested parties. A limited number of copies of the Environmental Assessment and the FONSI are available to fill single copy requests at the above address. Basic data developed during the environmental assessment are on file and may be reviewed by contacting Robert Jones.

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

Finding of No Significant Impact for the Construction of the Matanuska River, Spur Dike #5 at Circle View Estates, Palmer, AK

Introduction

The Construction of the Matanuska River, Spur Dike #5 at Circle View Estates, Palmer, AK is a Federally assisted action authorized through funding under the Watershed Protection and Flood Prevention Act (PL-83-566) 1954. An environmental assessment was undertaken in conjunction with the development of the implementation plan. This assessment was conducted in consultation with local, State, and Federal agencies as well as with interested organizations and individuals. Data developed during the assessment are available for public review at the following location: U.S. Department of Agriculture, Natural Resources Conservation Service, Alaska State Office, 800 West Evergreen Avenue, Suite 100, Palmer, AK 99645-6539, Phone: [phone], Fax: [phone].

Recommended Action

The Matanuska River is a glacially fed river system with highly braided channels. Severe bank erosion in the Circle View Estates area has been addressed previously through the installation of rock and earthen spur dikes. Erosion has continued downstream of the dikes, threatening adjacent bank and personal property (homes, buildings, appurtenances) and public infrastructure. The purpose of the project is to protect river bank, private homes and public infrastructure from loss to the erosive forces of the river at this subdivision site.

The preferred alternative is to install a barb-head spur dike, having river-directing flow features, which is believed to be potentially more fish-friendly than the previous adjacent dike designs. Completion of the project will reduce the risk of personal property loss, extend downstream protection of the existing four dikes, reduce emergency requests and response (as well as associated capital expenditures) by local government units, reduce potential harm or loss of human life, and protect public infrastructure in the area of influence of the dikes protection.

Alternatives

Two alternatives were not carried forward for additional development. These are nonstructural and combined actions. The nonstructural approach cannot be achieved by the proposed project as this requires state and/or local public policy changes. As the nonstructural approach is not being brought forward, the combined actions alternative cannot be further evaluated either.

Two alternatives were brought forward for further development. These are the bank protection alternative and no action alternative.

The preferred alternative selected is the installation of the barb-headed version of an additional spur dike. The proposed spur dike with barb head is a composite structure, consisting of a spur dike shank with the head of the dike designed as an overtopping barb. This design incorporates the overtopping feature of the barbs that work well in small streams and is considered more fish-friendly than the round-headed spur dike that has been shown to function in the braided channel. Barbs are built at an angle into the flow of water to redirect flows away from the bank and back towards the center of the channel, whereas the rounded spur dike head may direct flow back towards the bank between dikes. However, building a full barb structure into the Matanuska River would require a large amount of material and land due to the long distance from the shore to where the channel is being directed. The composite structure is intended to minimize rock fill requirements in the river while presenting a more fish-friendly approach to bank protection in a challenging braided river system.

Effect of Recommended Action

1. The spur dike is a proven bank protection technology on this stretch of river. The existing four spur dikes have protected the bank in their area of influence.

2. The modification to the head of the spur dike is expected to provide a more fish-friendly migration pathway than the round-head style currently on site. The barb-headed spur dike design allows the water to move differentially across the submerged portion of the dike head and thus adjust to flows. At higher flow rates, the barb-head design spreads the flow out and slows the velocity.

3. The affects of the spur dike are expected to be localized to the project area.

4. Approximately 0.5 to 1 acre of recovered riparian area for the spur dike will be established. Natural revegetation will occur along the bank and is expected to consist of locally available grasses, shrubs, and trees.

5. Reduce loss of land (approximately 1-4 acres) over next 50 years.

6. Reduction of long term maintenance and repair costs of lost infrastructure and residential structures (estimated at $0.5-1 million).

7. The new spur dikes will have minor effects on navigation in the river. The barb head design alternative features a submerged weir tip which is designed to overtop. This should not pose a significant hazard to navigation, however, because only shallow draft river boats will typically be present in the river, and the boaters are accustomed to shallow conditions which prevail in many areas of the river.

8. While there are initial capital and annual O&M costs for construction of the spur dike, these could be outweighed by the short and long-term costs to the community for loss of land, structures, infrastructure, and utilities.

General effects on the river will include:

9. Local diversion of the thalweg upstream and downstream of the spur dikes away from the river bank. Based on observations of this river and conventional experience with spur dikes, the influence zone is roughly 500 feet up and downstream of each dike. Beyond this distance, the Matanuska River could easily swing into the bank again.

10. Increase in erosive effects at or near structures due to increased flow velocities near tip of structures.

11. Possible increase of bank erosion immediately upstream or downstream of structures due to repositioning of thalweg.

There are no threatened and endangered species or state species of concern, known in the project area. However the river represents an important migratory corridor for five species of salmon. There are no known sole source aquifers, prime and unique farmlands, wild and scenic rivers or wilderness areas designated in the project area.

There will be no irretrievable and irreversible loss of natural resources, except for fossil fuel during construction activities and portions of needed equipment and materials which have no recycling potential. No impacts to cultural or historic resources will occur. No environmental justice issues are at risk.

No significant environmental impacts will result from installation of the proposed measures.

Consultation—Public Participation

An ongoing series of monthly meetings are held open to the public by the Circleview and Stampede Estates Erosion Service Area. The Draft Environmental Assessment for the project was published May 26, 2006. No comments or questions were received by the NRCS or the project sponsors.

A pre-application meeting was held on August 24, 2005 to discuss both the permitting and EA for this project. The purpose of this meeting was to introduce the project to the agency personnel who will be reviewing the permit applications and to ensure that their comments and concerns were incorporated into the EA and permit application.

Other agency contact includes several e-mails and phone calls between the Borough hired consultant and the agencies regarding structures or methodologies the agencies recommended for review.

At the request of NRCS, the consultant contacted via phone and e-mails the following Alaska native villages:

1. Chickaloon Village, Angie Wade.

2. Knikatnu Corp, Jennifer Raschke.

3. Native Village of Eklutna, Marc Lamoreaux.

An interdisciplinary group including the Matanuska-Susitna Borough Project Planning and Land Development Staff, PND Consulting Engineers, USDA Natural Resources Conservation Service (NRCS), biologists, engineers, environmental specialist, cultural resources coordinator, resource conservationist, and others helped gather basic project information, developed the preliminary determinations of the environmental and social effects of the alternatives, and provided input for the development of this document. Local area residents, as well as other private individuals and agencies, were contacted during plan development to provide needed information and coordinate activities.

Agency consultation and public participation to date have shown no unresolved significant conflicts with implementation of the selected plan.

Conclusion

The Environmental Assessment summarized above indicates that this Federal action will not cause significant local, regional, or national impacts on the environment. Therefore, based on the above findings, I determine neither the proposed action nor any of the alternatives is a major federal action significantly affecting the quality of the human environment, and that an environmental impact statement is not needed for the Construction in the Matanuska River of Spur Dike #5, at Palmer, Alaska.

Dated: July 20, 2006.

Thomas Hedt,

Assistant State Conservationist—Programs, NRCS.