Urban Stream Restoration Research Articles

Restoring nature in the city: Puget Sound experiences

Restoring nature within American urban areas seems basic to sustainability both in theory ( Hough, 1995) and in practice ( Sustainable Seattle, 1993). In addition to applicable science, restoration of urban green areas requires two complementary efforts, (1) a plan or process to locate and to rank potential restoration sites and (2) an understanding of how restoration designs will be accepted, and therefore, maintained by nearby residents. The urban Puget Sound region of Washington state has a 10 year history of stream restoration to improve salmonid habitats. This discussion reports on two regional research studies, one dealing with planning (Liberty Bay), the other with restoration design (Urban Streams). The first project, Liberty Bay, studied the feasibility of combining existing physical and political/social data to locate and rank potential restoration sites using a geographic information system. The study area was a small (<4000 ha) urbanizing watershed surrounding a polluted shellfish bay. The Liberty Bay study demonstrate the feasibility and identified the limits of combining physical data with social and political information. The second study, Urban Streams, is an ongoing, multidisciplinary effort to evaluate the efficacy of regional urban stream restoration as to stream dynamics, biotic conditions and human responses. The human response part of the Urban Streams study has two components. One is to analyze visual preferences for stream restoration engineering techniques. Salisbury (1997)used photo-simulated images of a proposed design to survey preferences. Her results demonstrated that respondents could differentiate various restoration designs based on their visual texture (rough to refined) and had clear preferences for the `refined' scenes in this urban regional context. The other study direction is to identify and evaluate human behavior toward urban streams. Initial results of this effort show that the majority of observed behaviors toward urban streams is negative. This result is disconcerting given the fact that the Puget Sound region has a reputation for a high degree of environmental sensitivity.

Use of Constructed Wetlands for Urban Stream Restoration: A CriticalAnalysis

/ Investigation of a delta marsh restoration project proposed forthe Don River in Toronto, Ontario, underlines several concerns aboutconstructed wetland projects designed for water quality improvement andaquatic habitat enhancement. The Don is a highly urbanized river that hasundergone significant physiographic modifications and continually receives acomplex mixture of conventional, metallic, and organic contaminants frommultiple point and nonpoint sources. Rather than providing permanent removalof urban contaminants, wetland processes offer a limited capacity fortemporary storage of contaminant inputs, and potential reactions may actuallyproduce more toxic and/or bioavailable forms of some chemicals. Theseprocesses tend to result in the concentration of watershed contaminants inwetland vegetation and sediments. As the restored marsh would be availablefor spawning and feeding by aquatic fauna, the potential exists for chemicalbioconcentration and biomagnification through the aquatic community.Accordingly, wetland systems are not suited to the dual purposes of waterquality improvement and aquatic habitat enhancement. Upstream controls,including source reduction of contaminant inputs, are recommended asessential components of all constructed wetland projects.KEY WORDS: Constructed wetlands; Water quality; Ecological restoration;Don River

Strawberry creek on the University of California, Berkeley campus: A case history of urban stream restoration

Abstract1. Strawberry Creek (37°52′ N; 122°15′ W) is the major focus of open space on the University of California, Berkeley (Alameda County, California, USA) campus; it provides visual amenity and variety, riparian and wildlife habitat, and educational and recreational opportunities.2. Since the beginning of this century, urbanization of the catchment, channel alteration and water quality degradation combined to cause deterioration of the creek's habitat and overall environmental quality; this was manifested by a marked absence of flora and fauna, obvious water pollution and severe erosion.3. In 1987 a restoration project was undertaken that focused on water‐pollution and erosion‐control measures. In 1989, native three‐spined sticklebacks (Gasterosteus aculeatus) were successfully reintroduced. Family Biotic Index scores for the macroinvertebrate community indicated a change from the ‘poor’ water quality conditions in 1986 to ‘good’ water quality in 1991.4. Environmental education programmes now involve over 1500 students who use the creek each year in laboratory exercises; a popular natural history and conservation walking‐tour guidebook has also been prepared.5. On‐going restoration efforts include additional reintroductions of other native species, further environmental education efforts and monitoring.6. Obstacles and key factors that led to the successful implementation of this project are presented to assist in implementing similar ecological restoration projects of urban streams.