Looking forward, looking back : monitoring the Tassajara Creek Restoration Project
Project monitoring has become a subject of increasing importance within the river restoration field. This study was completed as a post-construction evaluation of a restoration project completed in 1999 along a one-mile reach of Tassajara Creek near Dublin, California. Several objectives guided the design and implementation of the project, including that of protecting existing native trees and providing improved water quality. However, the main goal of the project was to stop incision on the channel, which, over the last century, had produced a deeply incised channel. A monitoring plan for this reach of Tassajara Creek, contained in an initial postproject evaluation completed in 2001, was implemented to evaluate the incision occurring on the creek. That same report found evidence that the creek had continued to incise since the project’s construction despite the restoration efforts. However, our study found that the project reach shows little or no evidence of incision, except for a few localized areas at the downstream end of the project reach. Although no evidence of incision was found, other evidence of deviations from the original restoration plan objectives were discovered. Our site work found several potential threats to the success of this project, including damage to existing native trees and a debris jam with the potential to degrade water quality in the creek. To account for these findings, and an appended monitoring plan was drafted so that the success of the project in meeting these additional objectives may be evaluated in the future. Because the study period for this project began only two years ago it is difficult to draw conclusions about the success of this project. Therefore, we recommend that project monitoring be continued in accordance with our monitoring plan so that the success of this restoration project can continue to be evaluated.