Science and Values in River Restoration in the Grand Canyon

estoration of riverine ecosystems is often stated as a management objective for regulated rivers, and floods are one of the most effective tools for accomplishing restoration. The National Research Council (NRC 1992) argued that ecological restoration means returning "an ecosystem to a close approximation of its condition prior to disturbance" and that "restoring altered, damaged, Of destroyed lakes, rivers, and wetlands is a high-priority task." Effective restoration must be based on a clear definition of the value of riverine resources to society; on scientific studies that document e~osystem status and provide an understanding of ecosystem processes and resource interactions; on scientific studies that predict, measure, and monitor the effectiveness of restoration techniques; and on engineering and economic studies