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Notice of Intent To Prepare a Draft Supplemental Environmental Impact Statement, Mill Creek Project Operation and Maintenance, Walla Walla County, in the State of Washington

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Department of the Army, U.S. Army Corps of Engineers, DOD.


Notice of intent.


The U.S. Army Corps of Engineers (Corps) intends to prepare a Supplemental Environmental Impact Statement (SEIS), in compliance with the National Environmental Policy Act (NEPA), for the continued operation and maintenance (O&M) of the federally managed portion of the Mill Creek Flood Control Project (Project) at Walla Walla, Washington, and implementation of actions to avoid or minimize potential effects to Endangered Species Act (ESA)—listed fish and/or associated critical habitat. The SEIS will supplement the June 1975, Mill Creek Project, Walla Walla, Washington, Final Environmental Impact Statement (FEIS), prepared by the Corps for the operation, maintenance, and improvement of the federally managed portion of the Project. The SEIS will identify and evaluate current O&M actions that may not have been adequately addressed in the 1975 FEIS or have been implemented since completion of the 1975 FEIS, and actions that are proposed for the future. It will also identify and evaluate operational and structural measures the Corps has proposed to improve fish passage through the Project. The 1975 FEIS did not adequately address the effects of the Project on fish species, particularly Mid-Columbia River steelhead and Columbia Basin bull trout. These species were listed under the ESA in the 1990's, and both Mill Creek and Yellowhawk Creek (a distributary of Mill Creek) have been designated as critical habitat.


Comments should be mailed to Walla Walla District, Corps of Engineers, CENWW-PPL-C, Mill Creek SEIS, 201 North Third Avenue, Walla Walla, WA 99362-1876, or submitted via email to and inserting “Mill Creek SEIS” in the subject line. Comments may also be submitted at the public scoping meeting.

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Questions about the proposed action and SEIS can be answered by Mr. Alex Colter, Project Manager, Walla Walla District, Corps of Engineers, CENWW-PM-PPL-P, 201 North Third Avenue, Walla Walla, WA 99362-1876, phone (509) 527-7254; or Ms. Sandra Shelin, NEPA Coordinator, Walla Walla District, Corps of Engineers, CENWW-PPL-C, 201 North Third Avenue, Walla Walla, WA 99362-1876, phone (509) 527-7265; or via email to and inserting “Mill Creek SEIS” in the subject line.

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The Mill Creek Flood Control Project (MCFCP) was constructed to provide flood risk reduction for the City of Walla Walla (City) and adjacent downstream areas. The major structural components of the Project were completed in 1942 with minor components added thereafter. Fish ladders were constructed in 1982. The federally managed portion of the MCFCP (Project) consists of a diversion dam on Mill Creek to divert flood waters about 11/2 miles upstream of the City to an off-stream storage reservoir (Bennington Lake); a dam that impounds Bennington Lake; a division works downstream on Mill Creek to direct flows into two distributaries, Yellowhawk and Garrison creeks; and about one mile of engineered channel extending between the diversion dam to just downstream of the division works. The local flood control district maintains the remaining six miles of engineered channel extending downstream from the federally managed channel through the City to Gose Street Bridge in Walla Walla County. The primary purpose of the Project is to provide flood risk management, but recreation was added as a project purpose in 1944. The Project also provides fish and wildlife habitat and recreational opportunities associated with fish and wildlife. For the purpose of this SEIS, the “Project” consists of only the federally operated and maintained portion of the MCFCP.

The Corps has identified several on-going O&M activities that may not have been adequately addressed in the 1975 FEIS or were implemented after the 1975 FEIS, as well as proposed new O&M actions. These include:

On-Going O&M

  • Update pest management to address invasive species.
  • Perform levee vegetation maintenance.
  • Periodically remove accumulated sediment from the diversion dam forebay.
  • Periodically remove debris from the Russell Creek Canal (used to drain flood flows from Bennington Lake).
  • Perform trail construction and maintenance.
  • Install recreation features such as benches and shelters.
  • Maintain a conservation pool for fish stocking and recreational use of Bennington Lake.

Proposed New O&M Actions

  • Plant food plots for pollinating insects.
  • Construct an interpretive center.
  • Use prescribed burning to manage vegetation.
  • Upgrade and improve the water seepage monitoring system at the storage dam.
  • Remove accumulated sediment from around the intake tower in Bennington Lake.
  • Evaluate the flow level for starting to divert flood flows into Bennington Lake.Start Printed Page 11025

The Corps initiated consultation with the National Marine Fisheries Service and the U.S. Fish and Wildlife Service (the Services) on the effects of Project O&M activities on species listed under ESA. As part of that consultation, the Corps has proposed several conservation measures that would modify structures or O&M of the Project. The Services are preparing their respective Biological Opinions (BiOps) and the Corps expects the Services may incorporate the conservation measures as part of their respective BiOps. The Corps will need to complete applicable environmental compliance, including evaluation under NEPA, prior to adopting and implementing any terms and conditions in the BiOps. The proposed SEIS would constitute that evaluation under NEPA. The Corps has proposed several measures to improve conditions for steelhead and bull trout, including the following, subject to authority and funding:

  • Use an existing Memorandum of Understanding with Washington Department of Ecology to continue to allow diversion of flows down Yellowhawk Creek during non-flood periods to benefit fish.
  • Construct a low flow channel through the remaining 81 weirs in the one-mile section of engineered channel managed by the Corps.
  • Construct a new fish ladder at the diversion dam.
  • Construct a new fish ladder at the division works.
  • Continue fish passage monitoring.
  • Continue to operate and maintain the rotating drum fish screens at the entrance to the intake canal to prevent diversion of fish to Bennington Lake during non-flood flow diversions.
  • Strive to make non-flood flow diversions to Bennington Lake when those diversions will not reduce flows in the engineered channel below an acceptable minimum flow.
  • Conduct fish salvage, as necessary, during O&M activities that have the potential to strand fish.
  • Use trap nets or similar methods to capture fish after a flood event if an unscreened diversion of flood flows into Bennington Lake occurs.
  • Perform in-water work during identified in-water work windows.
  • Take specific precautions to minimize effects of operating vehicles in or near streams.

The SEIS may address some of the measures, alternatives, and impacts on a programmatic level. However, the SEIS will present the coordination and environmental review steps the Corps will take with regard to any subsequent site-specific actions.

Request for Scoping Comments: The Corps invites affected Federal, state, and local agencies, affected Native American tribes, and other interested organizations and persons to participate in the development of the SEIS. The Corps invites interested parties to provide specific comments on issues and alternatives the Corps should evaluate in the SEIS related to the continued O&M of the Project. Comments, requests to be placed on the SEIS mailing list, and requests for information may be submitted to either of the addresses above. All comments and materials received, including names and addresses, will become part of the administrative record and may be released to the public. Interested parties should not submit confidential business or otherwise sensitive or protected information.

Public Scoping Meeting: The Corps currently plans to conduct a public scoping meeting for this SEIS in early 2017. The exact date, time, and location of the scoping meeting has not yet been determined. The Corps will publicize this information once the meeting arrangements have been made. The draft SEIS is currently scheduled to be available for public review in fall 2017. The final SEIS is currently scheduled to be available for public review in summer 2018.

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Lieutenant Damon A. Delarosa,

LTC, EN, Commanding.

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[FR Doc. 2017-03203 Filed 2-16-17; 8:45 am]