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COLUMBIA RIVER SALMON CUMULATIVE IMPACTS EXAMPLE
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Cumulative Effects Assessment 2 Example Learning Goals This example will provide insights into: The complexity of ecological systems Biological uncertainty; understanding is always incomplete Interactions between ecology, economics and policy Effects of institutional complexity; institutional roles must continually evolve
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Changes in Salmon Catch Associated with Hydropower Development
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Columbia River and Human Development
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Development Timeline 1850 1900 1950 Present Unregulated fishery Initiate fishery regulation US Federal Reclamation Act Irrigation New hydroelectric dams Add power capacity Flood control PNW Conservation Act
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Development and Impacts on Salmon Mortality on young Mortality on adults Loss of spawning habitat Altered hydrology Pollution Power Production Agriculture Flood Control Urban & Industrial Fisheries & Wildlife
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Cumulative Impacts and Habitat FRESHWATER Reduced Flows Predator Irrigation Siltation Reduced Flows Irrigation Turbines Predators Harvesting Spillways Obstacles Spillways Pollution Harvesting Pollution Estuary Downstream Losses - Smolts Upstream Losses - Smolts
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Cumulative Impacts and Harvest OCEAN US Harvest Canadian Harvest 20 Year Climate Cycles Productivity Predators Years 2 - 4 Known annual harvest ?
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Cumulative Effects Assessment 9 Summary of Impacts Direct Impacts »Losses at dams, habitat degradation, harvest, predation Indirect Impacts »Hydrology alteration »Oceanic cycles Impacts not additive and linear
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Measuring Impacts on Columbia River Salmon Catch and effort data Counts at dams Spawning escapement estimates Tag returns AbundanceData Understanding
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Cumulative Effects Assessment 11 Mitigating Cumulative Impacts in the Columbia River Fish Protection »Transport around dams »Dam renovation or removal »Water flow »Harvest restrictions Enhanced Fish Production »Hatcheries, artificial spawning channels Habitat Restoration »Protected areas: natural spawning beds »Forest management
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Cumulative Effects Assessment 12 Institutional Complexity Many agencies ‘steer the course’ Requires explicit consensus building Requires long-term commitment of funding
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Cumulative Effects Assessment 13 Unpredictable Events Effects on Columbia River Migrations: ~1978 - 1982: Failure of Nuclear Power Mitigation actions (small scale) Ocean temperature cycle (large scale)
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Cumulative Effects Assessment 14 Concluding Thoughts Important points to remember are: Cumulative impact problems are conceptually complex Mitigation is expensive and its effectiveness uncertain Common interests are more important than special interests
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Cumulative Effects Assessment 15 Concluding Thoughts (Cont’d) Additional points to remember are: Biological uncertainty is large Institutional complexity exceeds traditional approaches or experience Surprise is expected
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