Tradeoffs Between Implementation and Evaluation: Insights from the Trinity River Restoration Program

The goal of the Trinity River Restoration Program is to restore salmon and steelhead populations on a regulated river.  To meet this goal, the Program is attempting to restore the riverine processes that create and maintain salmonid habitats.  Management actions include mechanical channel rehabilitation, increased flow regimes, coarse sediment augmentation, and watershed restoration.  These actions are conducted under an Adaptive Management (AM) process to evaluate their effectiveness in meeting restoration objectives and Program goals. 

There are various spatial and time scales of adaptive management in the Trinity, ranging from annual decisions on flow and sediment augmentation, to periodic adjustments in rehabilitation site designs, to multi-decadal evaluations of the effectiveness of habitat restoration in meeting Program goals.  While considerable progress has been made over the last few years in monitoring and evaluation, there are considerable challenges in closing the AM loop.  A specific challenge to the Program has been to synchronize monitoring and evaluation activities with the implementation of management actions. In the case of mechanical channel rehabilitation, several factors confound and lengthen what appears to be a fairly simple process of site design, construction, monitoring, evaluation, and adaptation.  Channel rehabilitation has outpaced monitoring and evaluation, and changes in site design have generally been of an ad hoc nature.

Another challenge relates to the desires of managers and the public to have immediate feedback on the effect of restorations actions.  Directors of AM programs need to understand and convey that the benefits of restoration actions may take decades to realize.  With this in mind, it is critical to have an AM plan that conveys information of the effectiveness of restoration actions at intermediate steps to maintain support for restoration programs while the longer time scale processes are allowed to occur.

Lessons learned on the Trinity point to the need to have a well developed AM plan in place prior to initiating restoration activities, paying particular attention to the timing of activities so that feedback can be completed in a timely manner.  This is not only critical for conducting credible AM scientific evaluations but will also be help educate managers and the public about the timelines necessary to provide the answers concerning the effectiveness of restoration actions.