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• Shift the river over time to a relatively stable condition, in contrast to present conditions <br />where reaches vary longitudinally between degrading, aggrading, and stable conditions; <br />and <br />• Reduce the potential for degradation in the north channel of Jeffrey Island resulting from <br />headcuts. <br />PP-3: Designed mechanical alterations of the channel at select locations can accelerate changes <br />towards braided channel conditions and desired river habitat using techniques including: <br />• Mechanically cutting the banks and islands to widen the channel to a width sustainable by <br />program flows at that site, and distributing the material in the channel; <br />• At specific locations, narrowing the river corridor and increasing stream power by <br />consolidating over 90 percent of river flow into one channel will accelerate the plan form <br />change from anastomosed to braided, promoting wider channels and more sand bars. <br />• Clearing vegetation from banks and islands will help to increase the width-to-depth ration <br />of the river <br />PP-4: Higher water surface elevations resulting from raised river bed elevations can generate <br />measurable increases in the elevation, extent, frequency and/or duration of growing-season high <br />water tables in wet meadows within 3,000 feet of the river. <br />Physical Processes Hypotheses <br />Mechanical Creation and Maintenance Approach <br />• Hypotheses will be formalized and linked to CEMs prior to Program implementation. <br />III.C.S. Priority Hypotheses and Looking Outward Matrix <br />An initial list of priority hypotheses to be tested was developed by the AM Working Group and <br />must be agreed to by the Governance Committee prior to Program implementation using the <br />process described in I.F.1. above. Also, as the Program progresses, additional hypotheses are <br />likely to be added or modifications made to the existing hypotheses using the process described <br />in I.F.2 above. <br />Hypotheses are numerous and diverse and it is understood and agreed that not all hypotheses can <br />or will be addressed or investigated due to time constraints (certain responses to management <br />actions will take longer than the First Increment), physical limitations (only have so much water <br />and land), cost constraints beyond the scope and/or available resources of the Program, or <br />because they conflict with agreed upon policies. Therefore, hypotheses will be evaluated and <br />prioritized with the following guidelines (the numbering system used in the guidelines does not <br />reflect level of importance between different criteria). <br />Technical Guidelines (applied by ED, ISAC, and advisory committees): <br />1. Is there a scientific basis for the hypothesis based on existing data, information, and <br />reviews? <br />2. Is there a critical interdependency with a high priority hypothesis? <br />3. Will testing the hypothesis limit the opportunities to test other high priority hypotheses? <br />4. Is the hypothesis on a critical path to achieve Program goals and objectives - nice to <br />know versus need to know? <br />September 1, 2006 Adaptive Management Plan 17