03-12140. Notice of Availability of the Final Environmental Assessment and Finding of No Significant Impact for the Rehabilitation or Replacement of Diversion Dams on the Duchesne and Strawberry Rivers in Utah

AGENCY:

Utah Reclamation Mitigation and Conservation Commission (Mitigation Commission).

ACTION:

Notice of availability of the Final Environmental Assessment and Finding of No Significant Impact for the rehabilitation or replacement of diversion dams on the Duchesne and Strawberry Rivers in Utah.

SUMMARY:

The Central Utah Project Completion Act (Pub. L. 102-575) authorized Federal funds to rehabilitate diversion dams on the Duchesne and Strawberry Rivers in Utah. The project is needed to reduce adverse effects on fish and wildlife resources.

The Final Environmental Assessment (EA) was prepared as a Programmatic document. It discusses potential environmental impacts associated with reconstructing and operating an unspecified diversion dam on the Duchesne or Strawberry River. The new diversion dam could serve single or multiple diversion rights. Potential environmental impacts addressed in the document are those impacts that would be expected regardless of which diversion dam is rehabilitated. Potential impacts to wetlands, threatened and endangered species and cultural resources are generally site specific and/or require special permits. Potential impacts to these environmental disciplines would be addressed in a Supplemental Environmental Assessment (SEA), if needed.

After considering the public comments received during scoping and agency consultation, and the analyses in the EA of environmental effects, it is my decision to select Alternative 3 for implementation, excepting the combination of the Farm Creek, Jasper-Pike and New Tabby diversions. With Alternative 3, several of the existing diversions on the Duchesne River and several of the existing diversions on the Strawberry River would be combined and new diversion dams that would serve multiple diversion rights would be constructed. This would involve transferring points of diversion from the downstream diversion(s) to the upstream diversion that would be constructed. Diversions would be combined only when the involved water rights would not be adversely affected. However, not every diversion structure can be potentially combined with one or more of the other diversions. The combination of the Farm Creek, Jasper-Pike and New Tabby diversions as described under Alternative 3 is not approved to be combined into a single diversion because cumulative depletions of stream flows in the intervening approximately 1.4 miles of Duchesne River channel between the Farm Creek and Jasper-Pike diversions would cause a substantial adverse impact that would not be compensated for by the elimination of one or two of the diversions from the river. Alternative 3 was formulated to include consolidation of diversions that appeared feasible and reasonable based on physical and logistical considerations. At this time, potential legal, social, and institutional constraints have only been considered at a cursory level. Further examination of consolidation options could preclude some projects from being implemented. In those instances wherein Alternative 3 is determined not to be feasible, and in the case of the Farm Creek, Jasper-Pike and New Tabby diversions, Alternative 2 is selected for implementation. Alternative 2 involves the rehabilitation or construction of a new diversion facility on the Duchesne or Strawberry River at or in very close proximity to the location of the existing diversions.

The Final Environmental Assessment is a programmatic analysis. Potential environmental impacts addressed in the EA are those impacts that would be expected regardless of the diversion dam that is rehabilitated. Potential impacts to wetlands, threatened and endangered species and cultural resources generally are site specific and/or require special permits. As a subsequent decision to rehabilitate or reconstruct a particular diversion structure is made, the site-specific impacts will be assessed using a site-specific environmental evaluation checklist. If no additional impacts beyond those assessed in this EA are identified, the checklist will be approved as a decision document, and no further NEPA analysis will be conducted.

If any item on the checklist has not been satisfied, or if a project is expected to create impacts not described in the EA, to create impacts greater in magnitude or duration than described in the EA or would require mitigation measures that are not described in the EA to keep impacts below significant levels, a Supplemental EA (SEA) to address site specific impacts would be prepared for each diversion dam concurrent with the preparation of the final engineering or design report for a specific structure.

The EA was developed with the public in accordance with the Commission's National Environmental Policy Act (NEPA) rule (43 CFR part 10010.20). The Final EA and Decision Notice were sent to 28 agencies and individuals on May 2, 2003.

The EA is related to other potential future actions, specifically the detailed design and implementation of diversion dam replacements or rehabilitation. The programmatic perspective has been considered in the document. Future construction projects may require separate or supplemental NEPA compliance.

ADDRESSES:

Address all comments and/or requests for further information to Mark Holden, Projects Manager, Utah Reclamation Mitigation and Conservation Commission, 102 West 500 South, Suite 315, Salt Lake City, UT, 84101.

FOR FURTHER INFORMATION CONTACT:

Mark Holden, Projects Manager, 801-524-3146 [e-mail].

Dated: May 2, 2003.

Michael C. Weland,

Utah Reclamation Mitigation and Conservation Commission Executive Director.