Adaptive management is a resource management approach that acknowledges our limited understanding of how natural systems respond to human alterations by treating policies and management interventions in natural systems as experiments from which to learn. In a relatively new field such as river restoration, adaptive management is especially appealing, as it allows managers to learn while acting and promises to reduce uncertainty. By interviewing practitioners and reviewing restoration and adaptive management plans, I assessed the application of adaptive management in ten river restoration projects on the west coast of North America. Although definitions and applications of adaptive management vary widely among practitioners, the projects considered here share three common elements: recognition of uncertainty in river restoration and management, a commitment to monitor, and willingness to adjust actions based on information learned about the system. Most interviewees noted that it is too early to single out any positive ecological or social outcomes or even specific knowledge gained about the system through adaptive management; moreover, the site specific conditions of each stream have largely precluded knowledge transfer between restoration efforts. Practitioners identified a considerable number of barriers in attempting to implement adaptive management. Social and institutional challenges include high costs and limited availability of funding, a mismatch between the lengthiness of the adaptive management process and short funding cycles, agency and stakeholder impatience with the slow pace of adaptive management, a lack of leadership for monitoring and coordinating efforts, and risk aversion among agency personnel and stakeholders. Technical challenges encountered include a limited understanding of how to apply adaptive management and difficulties in translating results from site-level restoration projects to an understanding of the river system. The case study analyses suggest that the successful application of adaptive management will require long-term and stable funding, a long-term institutional commitment, greater leadership, more structured coordination, and training for resource managers.

Although lower Marsh Creek, in eastern Contra Costa County, CA, is heavily impacted by human activities on adjacent and upstream lands, scientists and residents have observed fall-run Chinook salmon in the channel. A grade control dam four miles from the mouth of the creek prevents Chinook from migrating to a more natural, unchannelized segment of lower Marsh Creek that may contain suitable spawning habitat. We assessed the quality of potential spawning habitat in a 1.2- mile reach of lower Marsh Creek. Through pebble counts and visual observations at six study sites between Concord Avenue and Marsh Creek Reservoir, we evaluated gravel quality to ascertain whether gravel sizes are within identified ranges for spawning, gravels are movable by spawning fish, fine sediment concentrations allow for egg incubation and fry emergence, and if gravel bars are large enough for spawning. Using a long profile, we investigated whether the gradient of the channel is acceptable for spawning. Using field measurements at our six study sites, along with USGS stream gauge records, we analyzed whether water velocities and depths during the fall months are suitable for salmon spawning.

Our results indicated that gravels in the study reach are at the smaller end of ranges reported in spawning studies and that gravels in the channel can be moved by spawning fish. Despite the presence of Marsh Creek Reservoir and Dam upstream of our study reach, gravels had a low level of embeddedness at half of six stations surveyed and moderate or high levels at the other half. Gravel bars are large enough for Chinook spawnin g. The average gradient of the channel bed is also acceptable for spawning. Water velocities and depths likely to support spawning are present about 2.5 percent of fall days (correlated to peak storm events). We concluded that the 1.2-mile stretch of lower Marsh Creek contains satisfactory habitat to support fall-run Chinook spawning. Based on these findings, we recommended removal of the grade control structure on lower Marsh Creek to allow salmon migration to the unchannelized section of lower Marsh Creek for spawning.