Successful stream rehabilitation requires a shift from narrow analysis and management to integrated understanding of the links between human actions and changing river health. At study sites in the Puget Sound lowlands of western Washington State, landscape, hydrological, and biological conditions were evaluated for streams flowing through watersheds with varying levels of urban development. At all spatial scales, stream biological condition measured by the benthic index of biological integrity (B‐IBI) declined as impervious area increased. Impervious area alone, however, is a flawed surrogate of river health. Hydrologic metrics that reflect chronic altered streamflows, for example, provide a direct mechanistic link between the changes associated with urban development and declines in stream biological condition. These measures provide a more sensitive understanding of stream basin response to urban development than do treatment of each increment of impervious area equally. Land use in residential backyards adjacent to streams also heavily influences stream condition. Successful stream rehabilitation thus requires coordinated diagnosis of the causes of degradation and integrative management to treat the range of ecological stressors within each urban area, and it depends on remedies appropriate at scales from backyards to regional storm water systems.

INTRODUCTIONIn-stream rehabilitation projects are commonly built in response to problems that result from both local sources and diffuse watershed degradation. Local problems, such as an improperly sized culvert, are relatively easily identified and corrected. Reversing the consequences of watershed degradation, such as channel widening and incision, is much more difficult if conditions that led to stream degradation remain unchecked. Despite this challenge, large amounts of money are being spent on in-stream projects in urban or urbanizing basins, because of numerous recognized problems on these streams, the interest of local communities in restoring the amenities these streams provide (Riley 1998, MacDonald 1995, and the relative ease and economy of site-specific in-stream work.This study investigates the effectiveness of one common technique, placement of in-stream large woody debris (LWD), to reverse local effects of watershed degradation in the absence of any systematic watershed-scale rehabilitation measures. To accomplish this, six stream rehabilitation projects in western Washington state that employ LWD were examined with the objective of answering the following questions:• Does in-stream placement of LWD produce physical channel characteristics typical of

ABSTRACT1. The planning, design and evaluation of a restoration project should be guided largely by an understanding of past channel changes.2. A historical analysis can sometimes reveal underlying causes of channel change and document prior habitat conditions, both useful in setting appropriate objectives for restoration.3. Restoration planning should address the historical causes and patterns of channel degradation that cannot be detected by examining current conditions alone. Moreover, ongoing adjustments in the channel and changes in the catchment must be understood when interpreting channel changes following construction of restoration projects.4. Changes in channel form (and the independent geomorphological variables of run-off and sediment load from the catchment) can be documented from a variety of sources, including historical maps, boundary lines, aerial photography, bridge and pipeline surveys, gauging records, field evidence and archival sources. Historical riparian vegetation, and use by fish and wildlife, may also be documented from early survey records, photographs and written accounts.

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