[PDF] Willamette River Floodplain Restoration Study eBook

Author : Saichon Seedang
Publisher :
Page : 298 pages
File Size : 42,24 MB
Release : 2004
Category : Ecosystem management
ISBN :

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In- stream water temperature is one of the most important environmental factors associated with the decline in salmonid populations and their habitats in the Pacific Northwest. Most ecological restoration practices that attempt to reduce instream temperatures center on replanting or reestablishing riparian vegetation and increasing flows. However, in a large floodplain river like the Willamette, restoring hyporheic flow may also play an important role in reducing water temperature. The objective of this dissertation is to examine restoration practices that focus on the reduction of water temperatures in the upper mainstem Willamette River, Oregon, for the benefit of salmonid species. Economic information is developed to determine the cost-effectiveness of water temperature reduction strategies. The CEQUAL- W2 water temperature model is used to simulate the effects of upstream combinations of riparian shading and flow increments on downstream water temperatures. Costs associated with these strategies are estimated. These costs consist of the opportunity costs of losing agricultural production, and losing recreation due to flow releases from up-stream reservoirs. The effectiveness of each strategy in reducing water temperature and the associated costs are used to construct a cost-effectiveness frontier. The results indicate that the cumulative effects of shading and flows have little impact on temperature reduction downstream. Even when maximum available resources are allocated to investments in shade and flow increases they cannot lower summer water temperatures sufficiently to meet the state water temperature standard. However, the restoration practices selected from the cost-effectiveness frontiers method do provide ranges of achievable temperature reductions at minimum costs. These results are thus useful management tools when selecting policies to pursue water temperature goals. Hyporheic temperature reduction is also examined. Restoration practices associated with this type of cooling are done through removal/reconnection of the obstacles that are necessary to allow the process of re-creating dynamic channel complexity. The observed significant reduction of summer water temperatures associated with channel complexity indicates that this approach is more flexible in reducing temperature than approaches that rely on flow increments or/and shade. Although the costs associated with the hyporheic approach are substantial, the effects of such a long-term ecological improvement of floodplain habitat may substantially benefit salmonid populations.

Author : David Hulse
Publisher :
Page : 178 pages
File Size : 29,8 MB
Release : 2002-01
Category : Nature
ISBN : 9780870715426

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"The Willamette River Basin Planning Atlas offers a valuable resource for anyone interested in the region's past, present, and future. Using a variety of color maps, charts, and photographs, the Atlas presents a vast amount of information intended to provide a long-term, large-scale view of changes in human and natural systems within the Basin." "Five chapters provide information on current conditions and historical changes since 1850, focusing in turn on land forms and geology, water resources, plants and animals, land use, and human population." "Next, there is a detailed examination of how the Basin may change between now and 2050 under three alternative scenarios for future land and water use: one assuming a continuation of current land use and management policies, the second assuming a loosening of current policies to allow freer development, and the third assuming greater emphasis on ecosystem protection and restoration." "The final chapter demonstrates how the information and analyses presented in the Atlas can be used to prioritize and design river restoration strategies. Although the focus is on the Willamette River and its floodplain, the book's approach provides a useful model that can be applied to other regions as well." "Intended for general readers and specialists alike, the Atlas provides information to help local citizens, policymakers, and scientists make better decisions about the Willamette River Basin and its future."--BOOK JACKET.Title Summary field provided by Blackwell North America, Inc. All Rights Reserved