Managing the Columbia River Instream Flows, Water Withdrawals, and Salmon Survival (2004) / Chapter Skim
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Executive Summary
Executive Summary
Pages 1-14
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With the introduction of an industrial based economy to the region in the late nineteenth century, the scale and rate of environmental variability in the basin changed. The creation of impoundments on the Columbia River and its tributaries, dam operations, commercial fishing, logging, diver sions for irrigated agriculture, and human population growth have altered the Columbia's presettlement flow regime and have reduced the quality of salmon habitat across the river basin.
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provide advice regarding salmon and water management decisions. In response to this re quest, the NRC reviewed and evaluated existing scientific data and analyses related to fish species listed under the Endangered Species Act in the Columbia River basin and reviewed and evaluated environmental parameters critical to the survival and recovery of listed fish species.
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Within the body of scientific literature reviewed as part of this study, the relative importance of various environmental variables on smolt survival is not clearly established. When river flows become critically low or water temperatures ex cessively high, however, pronounced changes in salmon mi gratory behavior and lower survival rates are expected.
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From page 4... ...
In addition to this "flattening" of the annual Columbia River hydrograph, other key impacts of the construction and op erations of the hydropower system were a decrease in water ve locities, a change in the size and orientation of the river's plume (a physical zone in the Pacific Ocean that extends from the Co lumbia's mouth into marine waters) , and major changes to lim
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The FCRPS today is operated primarily to provide benefits of flood control, hydropower, and instream flows. This study's focus was on the implications of potential addi tional water withdrawals (which would be primarily for irrigated agriculture)
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The scale of the Columbia River basin and current limits of scientific understanding of salmon and their habitat inhibit reli able, precisely quantified predictions of how additional water withdrawals will affect risks to salmon survival. Nevertheless, further reductions in river flows during low-flow periods will in crease those risks, especially since most of those withdrawals
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From page 7... ...
Decisions regarding the issue of additional water with drawal permits are matters of public policy, but if additional permits are issued, they should include specific conditions that allow withdrawals to be discontinued during critical pe riods. Allowing for additional withdrawals during the criti cal periods of high demand, low flows, and comparatively high water temperatures identified in this report would in crease risks of survivability to listed salmon stocks and would reduce management flexibility during these periods.
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From page 8... ...
Columbia River salmon are being subjected to a similar process. In isola tion, small additional water withdrawals each have an impercep tible effect on survival rates of salmon; but the cumulative ef fects of many small additional individual water withdrawals throughout the river's basin collectively could push salmon across life-threatening thresholds, particularly in critical periods of high demand and low flows.
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Convening the forum within a new simple framework could offer the advantage of greater flexibility and a clearer focus of responsibilities and obligations. Better Management of Existing Water Supplies Water management approaches such as water conservation and associated transfers, conjunctive use of groundwater, water markets, water banks, and environmental water accounts have the potential to support regional economic growth without re quiring additional Columbia River water diversions.
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MAKING COLUMBIA RIVER MANAGEMENT DECISIONS Washington State Department of Ecology Water Management Scenarios The water management scenarios proposed by the Washing ton State Department of Ecology and that were considered in this study contained many assumptions and actions related to water withdrawal quantities, management actions, and water use fees (key features of the scenarios, and comments that resulted from this study, are listed below; Appendix A lists these scenarios in their entirety)
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From page 11... ...
Uninterruptible water rights are pre-1980 state law water rights that have priority over mainstem instream flow rights that were established in 1980. These rights stand in contrast to inter ruptible water rights, which may be curtailed under certain low flow conditions to protect mainstem instream flows.
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From page 12... ...
Structural measures imply that tributaries are to be used for additional storage, but ecological habitat and conditions in tribu taries are important for many reasons, including their relation ship to Columbia River salmon survival. Tributaries should be considered for protection and for mitigation as well.
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The creation of comprehen sive management strategies that enhance viable salmon popula tions, that calm disputes, and that meet human and economic demands will likely require a flexible and collaborative decision making approach that involves scientists, managers, and decision makers. Science has contributed greatly to the collective knowl edge of Columbia River salmon, but "better" or "more" scientific information will not necessarily lead to the resolution of disputes or to better management decisions.
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From page 14... ...
A process in which scientists monitor the outcomes of management actions and provide feedback to stakeholders and decision makers (who then adjust management actions accordingly -- generally referred to as "adaptive management") will be instrumental in helping understand how additional scientific research can best support management decisions.
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