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1994 Columbia River Basin Fish and Wildlife Program |
| Council document 94-55 | |
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5.6 Complete Installation of Bypass Systems
When the first hydroelectric dams were constructed in the mainstem of the Columbia River, many people believed that providing adequate upstream passage over the dams for adult salmon returning to spawn was sufficient to sustain salmon and steelhead runs. Since that time, research has shown that juvenile salmon and steelhead heading downstream also suffer a significant mortality rate as they encounter the dams.
Pressure changes within each turbine are the primary cause of juvenile salmon deaths. The impact of the moving turbine blades and the shearing action of water in the turbine can cause injuries or death. In addition, juvenile salmon and steelhead may be stunned while passing through the turbines, thus increasing their vulnerability to predators, especially squawfish, which are abundant at the base of each dam. The Council recognizes the need to address all phases of mainstem salmon survival, including installation of juvenile fish screening and bypass systems.
The Council has taken a number of actions to reduce mortality rates of juvenile fish at the dams. It has called for permanent bypass facilities to be installed at mainstem dams. However, to protect juvenile fish while these installations were being built, the Council required dam operators to spill sufficient water at the dams to guarantee a specified level of fish survival. With spill, fish-laden water is diverted through a spillway, passing the dam without going through its turbines. (Spill is to be distinguished from the water budget in that spill helps juvenile fish around the dams. The water budget speeds the migrants' journey between dams.) The Council also adopted measures to transport juvenile salmon and steelhead around some dams, as determined by the fish and wildlife agencies and tribes.
In 1982, the Council called for development of mechanical bypass systems at five public utility district dams regulated by the Federal Energy Regulatory Commission in the mid-Columbia area. In 1984, operators of four of the five dams agreed to develop bypass systems as part of a settlement with fish and wildlife agencies and tribes, which had petitioned the Federal Energy Regulatory Commission to make bypass a condition of license renewals for the dams. Spill, which is to be used to protect fish until the bypass systems are operating, is to be shaped in coordination with the fish and wildlife agencies and tribes. In 1987, the Council amended the program to incorporate provisions of a settlement agreement concerning fish protection measures at Rock Island Dam. The settlement capped several years of litigation over the advisability of mechanical bypass systems for juvenile fish, whether a hatchery would be a reasonable substitute, what level of spill would be appropriate to protect juvenile fish and other issues. The settlement agreement calls for the development of juvenile bypass systems and installation of the systems, if certain criteria are satisfied. The agreement also provides for the creation of an innovative ?Fisheries Conservation Account,? which the joint fishery parties that have signed the agreement may use for bypass studies, bypass development or to purchase spill. The agreement specifies spill levels and provides for studies of summer spill. A hatchery and satellite facilities will be constructed promptly, and habitat and other studies will be conducted to help determine the proper use of the fish produced. Changes were also made in adult fishway operating criteria and modifications.
In 1984, the Council considered a number of proposals for improving fish passage efficiency and smolt survival at Columbia and Snake river dams with the goal of improving smolt survival systemwide. Some recommendations proposed waiting for results of studies on fish passage problems before taking action to improve bypass efficiencies. The Council, however, found that the critical status of the runs on the Columbia and Snake rivers requires prompt action instead of continued delay and study. As a result, amendments to the program called for the Corps of Engineers to develop coordinated interim juvenile fish passage plans, including spilling water over the dams, while developing permanent solutions to passage problems at John Day, The Dalles, Bonneville, Lower Monumental and Ice Harbor dams.
At the Council's request, the Corps completed a comprehensive report on smolt transportation in 1986. In addition, the Council adopted a 90-percent fish guidance efficiency standard as a design criterion for devices that deflect fish away from turbine intakes. The Council required that the level of spill be sufficient to guarantee at least 90-percent fish survival at specified projects for the middle 80 percent of the spring and summer migrations until mechanical bypass systems are installed.
In 1987, the Council adopted a ?share the wealth? measure to provide increased levels of spill in years when water is above the critical level. Recognizing that many of the issues associated with spill have been institutional in nature, the Council committed to aid agreement among the fish and wildlife agencies, Indian tribes and the Corps on this ?sliding scale? approach to spill and on other matters.
In 1988, the Bonneville Power Administration, state and federal fish and wildlife agencies, Indian tribes and utility representatives negotiated an agreement on spills for a 10-year period beginning December 31, 1988, at Lower Monumental, Ice Harbor, John Day and The Dalles dams.
In this section, the Council establishes performance standards and sets schedules for the installation of new or improved screens and bypass systems at all Snake and Columbia river federal dams. The Council also calls for monitoring and evaluation of existing screens and new screen designs for improved effectiveness.
5.6A Improve Columbia and Snake River Salmon Passage
Biological objective:
To minimize delay at dams, and minimize the passage of juvenile fish through turbines by providing high survival alternative passage routes.
Operational objective:
To achieve 80 percent fish passage efficiency at each Snake River project from April 15 to July 31 and at each Columbia River project from May 1 to August 31, while keeping dissolved gas levels within the limits of federal and state water quality standards and ensuring a high degree of adult passage success.
Corps of Engineers
5.6A.1 Develop and implement a coordinated permanent juvenile passage plan, in consultation with the fish and wildlife agencies and tribes, consisting of a schedule for design and installation of a powerhouse collection and bypass system at Ice Harbor and The Dalles projects. (Unless otherwise allowed by the Ten-Year Spill Agreement, use a 90-percent fish guidance efficiency standard as a design criterion for turbine intake screens and surface bypass systems. However, the standard need not be used if it is demonstrated to the Council's satisfaction, on the basis of hydraulic model studies or prototype testing of surface bypass systems and biological test results, that the 90-percent standard cannot be achieved.) The Corps should measure fish guidance efficiency and report results to the Council.
5.6A.2 Install and provide operational fish passage screens and bypass systems at all unscreened federal mainstem dams according to the following schedule:
Ice Harbor: Provide a completed and operational screening and low-velocity flume bypass system by March 1996.
The Dalles: Provide an operational screening and bypass system by March 1998. If a surface bypass system prototype is tested at The Dalles Dam, then complete engineering design for a screened bypass system, but defer screen procurement and construction contracts until testing is complete. Testing should take no longer than two years. In either case, install an operational powerhouse juvenile fish bypass system by March 2000.
5.6A.3 Ensure a 98-percent or greater salmon survival rate in all bypass and collection facilities from the deflector screens or surface bypass system entrances to the end of the bypass system outfall. Where possible, increase survival of smolts in the area below the bypass release points by removing fish predators, protecting migrants from predation by birds, providing alternative release sites or relocating bypass outfalls, particularly at Bonneville Dam by 1998, and/or modifying project operations to reduce predation, according to the schedule in Table 5-2.
5.6A.4 Complete evaluation, design and prototype testing of extended length fish screens, and, if more effective than surface bypass systems, install them at all Snake and Columbia river dams.
5.6A.5 During design and preparation for installation of fish passage facilities, evaluate and report to the Council concerning modifications that may be needed to accommodate alternative flow and velocity measures outlined in Section 5.3 (Snake River Reservoir Drawdown Strategy).
5.6A.6 Expedite evaluation of fish passage efficiency at Bonneville Dam First Powerhouse and report to the Council modifications that may be needed to meet the standards in Section 5.6A.1. Expedite rehabilitation of old generating units. By 1996, investigate project operating systems to provide independent operation of each powerhouse and modify an operating system by March 1998. Complete prototype testing of a surface flow juvenile bypass system by 1998.
5.6A.7 At The Dalles and Lower Granite, complete prototype testing of a surface flow juvenile bypass system by 1998.
5.6A.8 Investigate the feasibility of building a fisheries engineering research facility in the Columbia River Basin to evaluate how fish respond to various fish passage design structures and new fish passage technologies. Report progress on this study by end of 1995.
5.6A.9 Evaluate and modify, if necessary, the juvenile mechanical bypass system at John Day Dam, especially the collection channel and outfall. Complete prototype testing of a surface flow juvenile bypass system by 1998.
5.6A.10 Continue studies at McNary Dam to evaluate the expanded juvenile fish bypass and collection system and make necessary modifications by 1995.
5.6A.11 If initial testing at Ice Harbor and prototype testing of surface bypass systems at other mainstem dams indicate potential for improved fish passage at Ice Harbor Dam, complete prototype development and testing of a surface bypass system by 1998.
5.6A.12 Complete comprehensive evaluation of new mechanical bypass systems at Lower Monumental and Little Goose dams by 1995.
Corps of Engineers and Other Parties
5.6A.13 Explore promising new approaches to fish bypass technologies, including development and prototype testing of surface bypass systems, surface spill and behavioral guidance devices, such as the use of sound to guide fish. If the results of this research indicate high efficiency at costs less than screen or other bypass system modifications and show no reason to preclude use of a new technique, propose to the Council incorporation into bypass strategies.
5.6A.14 Conduct laboratory studies, numerical analysis, hydraulic model studies and prototype testing to develop an improved understanding of the mechanisms of fish mortality in turbines. Use this information to develop biological design criteria to be used in advanced turbine designs or modified unit operations to increase fish survival. Report results of studies by September 2001. Based on results of studies, replace or rehabilitate existing turbines, or modify turbine operations at mainstem Columbia and Snake river dams.
5.6B Mid-Columbia River Salmon Passage
Mid-Columbia Public Utility Districts
5.6B.1 Subject to Federal Energy Regulatory Commission approval, coordinate and consult with the fish and wildlife agencies and tribes through the three coordinating committees (Wells, Rock Island and Mid-Columbia) on the design of prototype bypass system studies, research, evaluation and all other activities required in this section to achieve the most effective permanent solutions to juvenile fish passage problems in the mid-Columbia. By March 20 of each year, develop and submit to the Federal Energy Regulatory Commission, members of the coordinating committees and the Council an annual fish passage and project operational and maintenance plan. The annual fish passage plan for the mid-Columbia public utility district projects should be coordinated with the various annual implementation plans developed under the auspices of the Fish Operations Executive Committee. At the request of the tribes, fish and wildlife agencies or public utility districts, the Fish Operations Executive Committee and/or the Council will help resolve any disputes related to achieving the objectives of this plan.
Douglas County Public Utility District
5.6B.2 Subject to Federal Energy Regulatory Commission approval, ensure that the installed juvenile fish bypass system tailored to the unique features of Wells Dam continues to operate effectively and in accordance with the terms and conditions of the 1990 Wells Settlement Agreement.
Chelan County Public Utility District
5.6B.3 Evaluate, design and install a prototype surface collection and bypass system at Rocky Reach Dam by 1995. Review with the Mid-Columbia Coordinating Committee, the need for and, if needed, make structural repairs to the spillway so the spillbays closest to the powerhouse can operate independently. If prototype testing indicates higher passage efficiency compared to screen modifications and shows no reason to preclude use of a surface bypass system, install a surface bypass system instead of turbine intake screens.
5.6B.4 Subject to Federal Energy Regulatory Commission approval, complete installation at Rock Island Dam of a juvenile fish screening and bypass system, as set forth in Sections B and C of the Rock Island Settlement Agreement.
5.6B.5 Subject to Federal Energy Regulatory Commission approval, develop plans for spills at Rocky Reach and Rock Island projects by March 1 of each year, as set forth in the stipulated agreement for Rocky Reach Dam and the 1986 Settlement Agreement for Rock Island Dam (Section C, ?Fisheries Conservation Account,? or Section D, ?Spill Program?).
Grant County Public Utility District
5.6B.6 Subject to Federal Energy Regulatory Commission approval, complete testing and evaluation of prototype juvenile fish screening and bypass systems at Wanapum and Priest Rapids dams, and report the results of such tests and evaluation to the Council and the Federal Energy Regulatory Commission.
5.6B.7 Subject to Federal Energy Regulatory Commission approval, complete installation at Wanapum Dam of a fully operational juvenile fish screening and bypass system by March 1, 1998, or inform the Council of the reasons why this date cannot be met.
5.6B.8 Subject to Federal Energy Regulatory Commission approval, complete installation of a fully operational juvenile fish screening and bypass system at Priest Rapids Dam by March 1, 1997, or inform the Council of the reasons why this date cannot be met.
5.6B.9 Subject to Federal Energy Regulatory Commission approval, provide an increased level of spill at both Wanapum and Priest Rapids dams to improve fish survival for 80 percent of both the spring and summer salmon migrants, while avoiding dissolved gas supersaturation problems. The Mid-Columbia Coordinating Committee will have the responsibility to govern the timing and distribution of spill. Implement such a plan for spill each year at Wanapum and Priest Rapids dams until juvenile fish screening and bypass systems are installed and operational at each project.
5.6B.10 Subject to Federal Energy Regulatory Commission approval, explore promising new approaches to juvenile fish bypass technology, including the use of surface bypass systems, by 1996. If prototype testing indicates higher passage efficiency compared to screen modifications and shows no reason to preclude use of a surface bypass system, install a surface bypass system instead of turbine intake screens.
5.6C Spill
Corps of Engineers, Bonneville and Other Parties
5.6C.1 Consistent with the experimental program developed under Section 5.0, and until better means are available to move juvenile migrants past dams, for mainstem projects operated by the Corps of Engineers on the Columbia and Snake rivers, provide spill to achieve 80 percent fish passage efficiency at each Snake River project from approximately April 15 to July 31, and at each Columbia River project from approximately May 1 to August 31, or as near as possible within the total dissolved gas guidelines established by federal and state water quality agencies. Manage the spill program in close cooperation with National Marine Fisheries Service and fish managers to ensure appropriate responses to monitoring information for gas bubble trauma. Exceptions to the state standards should be approved by the states on a showing, by the National Marine Fisheries Service and state and tribal fishery managers, that the risk of fish mortality from exposure to higher levels of dissolved gas is less than the risk of failure to provide the spill regime that may result in such levels.
Fish Managers, State Water Quality Agencies and Corps
5.6C.2 Prior to use of spill for fish passage in 1995, develop and implement a monitoring and spill management program for ambient nitrogen supersaturation levels, symptoms of gas bubble trauma, and systemwide effects of spill to ensure safe passage conditions for both adult and juvenile salmon.
Idaho, Oregon and Washington water quality agencies and Corps
5.6C.3 Develop and implement a network of water quality monitoring telemetry stations on the Snake and Columbia rivers and evaluate data produced by the system.
5.6D Turbine Operating Efficiency
Corps of Engineers
5.6D.1 Operate turbine units within 1 percent of peak operating efficiency from April through August of each year, and especially during peak migration periods. Plan and coordinate deviations from the 1-percent peak efficiency criterion with the fishery agencies and tribes. Complete the turbine index testing program at all mainstem dams by 1996.
5.6E Gas Supersaturation
Bonneville, National Marine Fisheries Service
5.6E.1 Fund a study of dissolved gas supersaturation and its effects on salmon and steelhead passing through dam turbines, collection and bypass systems, spillways, adult ladders, reservoirs and other mechanisms, particularly in connection with possible reservoir drawdowns. The study should focus on the relationship between: a) spill levels at mainstem federal projects and the resulting total dissolved gas level; and b) the symptoms of gas bubble trauma related to both lethal and non-lethal effects on juvenile and adult salmon and other aquatic species. Report to the Council by January 1, 1997.
Corps of Engineers
5.6E.2 By 1997, evaluate and modify mainstem projects to reduce dissolved gas levels during spill operations and increase spill efficiency. Include the following options in the evaluation:
- Installation of spillway deflectors at each of the following dams: Lower Granite, Little Goose and Lower Monumental (two outer spillbays); McNary (four outer spillbays); Ice Harbor, John Day and The Dalles (all spillbays); and Bonneville (two outer spillbays);
- Design and prototype test spillway and stilling basin modifications;
- Design and prototype test structural and fish behavioral methods to increase fish passage efficiency of spillways and control nitrogen supersaturation, including the use of a slotted spillgate design; and;
- Fund extensive hydroacoustic monitoring across the length of each dam to monitor smolt movement, determine spill efficiency and improve the effectiveness of spill passage.
Corps of Engineers
5.6E.3 Fund or install the following dissolved gas monitoring and abatement measures:
- a more extensive dissolved gas monitoring system so physical aspects of gas plumes can be identified in the water column;
- state water quality agencies and fishery agency and tribal entities to conduct physical and biological monitoring and evaluate data gathered by monitoring program;
- supply additional gas monitoring equipment for backup installation and readiness for immediate use;
- continued development and calibration of existing gas spill model to enable accurate prediction of dissolved gas levels under different riverine and spill conditions on a real-time basis;
- gas abatement structures at all Corps dams by 1997; and
- operational and structural measures to reduce high total dissolved gas levels caused by turbine discharges from headwater storage projects.
5.6F Develop and Implement Maintenance Plans
Federal Project Operators and Regulators
5.6F.1 Develop a plan for repair and maintenance of any part of each dam relating to the passage of juvenile salmon and steelhead, including: 1) measures to be followed in the event that any such facility breaks, is washed out or ceases to operate; and 2) designation of an individual responsible for carrying out the plan. If any dam operator fails to comply with the plan, the Council will ask the person responsible for carrying out the plan to explain at a Council meeting the reasons for the non-compliance. The Council will decide upon appropriate action at that time.