5.3  Snake River Reservoir Drawdown Strategy

Drawdowns to near-spillway crest elevations of the four lower Snake River projects offer an alternative for improving mainstem survival. The Council believes that a properly designed drawdown of Lower Granite pool will produce essential biological information needed before a long-term commitment to drawdown of the lower Snake projects is decided. Therefore, the Council calls on the Corps of Engineers immediately to take all steps needed to proceed with a Lower Granite drawdown.

      The Corps of Engineers should not view the Lower Granite drawdown as a one-time test but rather as the first stage of an adaptive management plan. Knowledge gained from the Lower Granite drawdown regarding turbine efficiency, turbine mortality, smolt travel time and adult passage should be used in deciding about continuing the Lower Granite drawdown and how a 1999 drawdown of Little Goose reservoir could be achieved if it is biologically prudent. Information, gained from the 1999 drawdown, including but not limited to adult passage mortality and gas supersaturation control from downstream weirs, should, in turn, be used in deciding if and how a 2002 drawdown of all the Lower Snake reservoirs could be achieved. The objective of the Snake River drawdown is endeavoring to achieve a 140,000 cubic feet per second velocity equivalent in all water years.

      Using adaptive management techniques for each stage of the drawdown plan is also essential because it is possible that some of the central components of the ultimate drawdown strategy will not be fully completed in time for the Lower Granite drawdown. The Council calls on the Corps to take the steps needed to prevent or minimize any likely negative impact to salmon resulting from any element of the drawdown strategy being incomplete. However, the Corps should not fail to meet the drawdown implementation schedule merely because an element of the ultimate strategy is incomplete.

      Snake River flow augmentation and transportation measures, described in Sections 5.2 and 5.8, will be pursued pending implementation of the Snake River reservoir drawdowns. The Council will review and re-evaluate transportation and flow measures as drawdowns  are implemented. It is the intent of the Council that these measures will be in addition to or complement measures already initiated to achieve rebuilding targets, and that mitigation measures (including mitigation for transportation rate increases) be in place before drawdowns are implemented.

5.3A  Initial Lower Granite Drawdown

Corps of Engineers

5.3A.1  In consultation with the fishery managers of the Columbia River Basin, as a recovery action/test, implement a two-month drawdown to elevation 710 feet at Lower Granite from approximately April 16 to June 15 starting in 1995. The 1995 Lower Granite drawdown is contingent on:

1. The manufacture of dipping baskets capable of handling the smolts that enter the gatewells;
2. Conditions where the number of migrating smolts will not overwhelm the dipping basket system prior to peak; and
3. Any needed modification of the adult ladder exit.

      The Lower Granite drawdown should contain the following elements:

1. The fishery managers will develop a spill management and monitoring plan for use by the Corps of Engineers before implementing a spill program associated with the Lower Granite drawdown. The purpose of the spill program is (in order of priority) to be consistent with state water quality standards; to ensure acceptable adult passage conditions; and to provide 80 percent fish passage efficiency.
2. The Corps will extend auxiliary water pumps for the adult fish ladder to permit a maximum drawdown of 690 feet above mean sea level.
3. The Corps will commence refill of Lower Granite pool in mid-June. Minimize impacts on June flows by shifting a portion of the spring water budget into the June period.

      If dipping baskets are not capable of adequately handling fish in gatewells or if insurmountable obstacles preclude implementation of the above described elements in time for the 1995 drawdown, immediate action must be taken to ensure that a 1996 drawdown of Lower Granite can be implemented. The 1996 drawdown should incorporate the lift tank system of salvaging fish from gatewells. The Corps should undertake actions to reduce the lead time needed to implement a Lower Granite drawdown as quickly as possible.

Corps and Bonneville

5.3A.2  Using Congressional appropriations, borrowing, or other authorities, whichever is more expedient, fund modifications necessary to permit drawdown of the Lower Granite pool, and mitigation, including a mitigation program in place prior to drawdown. In order to mitigate for the physical and economic impacts of the 1995 drawdown of Lower Granite, and until additional mitigation procedures can be put in place, use the claims procedures that were established to mitigate the effects of the 1992 Lower Granite drawdown test. Mitigation claims should be processed more expeditiously than occurred during the 1992 drawdown test. It is the Council's expectation that mitigation funds will be made available to affected parties as soon as possible.

5.3B Additional Lower Snake River Drawdown

Corps of Engineers

5.3B.1  In consultation with the fishery managers of the Columbia River Basin, complete the following modifications to Lower Granite and Little Goose by 1998:

1. Install either lift-tanks or improved dip net baskets, or a combination, at Lower Granite.
2. Construct rock weirs on the downstream side of Lower Granite dam.

5.3B.2  Upon completion of these measures, in consultation with the fishery managers of the Columbia River Basin after Council review and absent Council disapproval, implement as a recovery action/test:

1. By 1996, the drawdown of Lower Granite to elevation 690 feet between approximately April 16 and June 15. Commence refill of Lower Granite pool in mid-June.
2. In 1995, begin all design, engineering and environmental review activities necessary to allow construction activities to begin in January 1997 to permit drawdown of Little Goose. By January 1997, after Council review and absent Council disapproval, begin construction. In 1999, after Council review and absent Council disapproval, drawdown Little Goose to elevation 590 feet for the same time period. Commence refill of Little Goose pool in mid-June.

5.3B.3  Continue the drawdown program for the years following. The drawdowns will also be consistent with the fishery managers? spill management and monitoring plan described above. Minimize refill impacts on June flows by shifting a portion of the spring water budget into the June period.

5.3B.4  Report to the Council in March 1995 on: a workplan to meet the drawdown timelines described above; whether private engineering assistance is required to meet these schedules; and a proposal for securing such assistance. If needed, accelerate the System Configuration Study to meet this schedule, and include in the study an evaluation of spillway as well as natural river level drawdowns.

Council

5.3B.5  Using best available scientific information regarding flow and velocity contributions to life-cycle survival and experience with juvenile passage in connection with Lower Granite drawdown review and, after Council review and absent Council disapproval, proceed with 1997 construction and 1999 drawdown of Little Goose.

Corps and Bonneville

5.3B.6  Using Congressional appropriations, borrowing, or other authorities, whichever is more expedient, fund modifications necessary to permit drawdowns of the Lower Granite pool by 1996 and Little Goose pools by 1999.

5.3B.7  Using appropriations or borrowing, whichever is more expedient, fund ongoing evaluation of reservoir and life-cycle survival consequences of drawdowns.

Corps of Engineers

5.3B.8  Beginning immediately, and concluding not later than December 31, 1997, complete all design, engineering and environmental review of facility and operating changes necessary to operate Lower Granite, Little Goose, Lower Monumental, and Ice Harbor projects near spillway and/or natural river level: a) annually, from April 16 to June 15; or b) year-round. Include all requirements and impacts relating to power production, flood control, navigation, irrigation and other river uses. Report results to the Council by December 31, 1997.

Council

5.3B.9  Based upon information gained from the drawdown of Lower Granite and Little Goose pools, determine by 2002 whether to implement the drawdown of Ice Harbor and Lower Monumental pools to spillway and/or natural river levels.

Corps of Engineers

5.3B.10 Secure any necessary authorization and comply with all required legal processes to permit reservoir drawdowns. Implementation of the lower Snake River drawdowns will be consistent with the fishery managers? spill management and monitoring plan.

Fishery managers

5.3B.11 By 1996, develop a monitoring program before Corps implementation of drawdown to determine whether the drawdowns reduce travel time for juvenile salmon and sustain an 80-percent fish passage efficiency rate or lower based on the maximum allowable dissolved gas level.

Corps and Bonneville

5.3B.12 Using Congressional appropriations, borrowing, or other authorities, whichever is more expedient, fund necessary project modifications and mitigation measures to permit drawdown of the Lower Snake reservoirs, including plans to protect cultural resources at the four lower Snake reservoirs during drawdown.

5.3B.13  In consultation with the fishery managers of the Columbia River Basin, starting as early as possible in 1992, conduct any tests necessary to assist in the formulation of the plans called for in this section.

Council

5.3B.14 Establish a committee to coordinate analyses conducted by the federal agencies and  to oversee the development of drawdown plans and structural modifications to both juvenile and adult fish passage facilities, as described in this section and in Section 6. The committee, chaired by the Council, will consist of a representative from each of the following: National Marine Fisheries Service, Corps of Engineers, Bonneville, Bureau of Reclamation, Idaho, Montana, Oregon, Washington and Indian tribes. The committee's work will facilitate regional involvement in ongoing federal processes relating to lower Snake River reservoir drawdowns and will help prevent unnecessary duplication between federal and Council-sponsored efforts. The Council will provide ongoing coordination with other interested parties in the region and will be responsible for overseeing the development, scheduling and completion of the plans called for in this section, in consultation with the National Marine Fisheries Service.

Bonneville

5.3B.15 In coordination with the committee, a) fund independent technical resources, as needed, to enable the committee to review the adequacy of analyses conducted by the federal agencies and to conduct their own analyses when the committee or the chair deem appropriate. Funding will be based on a scope of work approved by the Council no later than two months following adoption of this rule. b) Fund an independent panel of experts, preferably one that is already established, to evaluate current bypass technology relative to fish guidance efficiency, fish passage efficiency and survival at mainstem Columbia and Snake River dams. The panel of experts should compare the data to the guidance and passage efficiency standards adopted by the Council and provide recommendations to the committee regarding their evaluation. The experts should also consider the feasibility of using spill in conjunction with mechanical passage measures without violating federal or state water quality standards as appropriate for gas supersaturation.

Federal Project Operators and Regulators

5.3B.16 Implement approved plans in accordance with the schedule adopted by the Council. To ensure prompt implementation of any plans approved by the Council, federal implementing agencies should incorporate the planning process and its results into ongoing administrative processes including, but not limited to, National Environmental Policy Act and Endangered Species Act processes.

5.3B.17 Incorporate the specifications of such approved plans in all system planning and operations performed under the Columbia River Treaty, the Pacific Northwest Coordination Agreement, Congressional authorizations and appropriations, all related rule curves and other applicable procedures affecting river operations and planning. Implement approved reservoir drawdown plans as ?firm? requirements.

5.3C Mitigation and Assistance for Property Owners

Corps of Engineers

Develop a mitigation plan that will assist local property owners in minimizing the impacts to buildings, facilities and roads that may result from each stage of the lower Snake River drawdown. The Corps should submit this mitigation plan to the Council no later than six months prior to the beginning of the Lower Granite drawdown and submit similar plans prior to each subsequent drawdown.

< back  |  ^ top  |  next >