Spawning Habitat Rehabilitation

Altered sediment and flow regimes in dammed and regulated rivers limit available spawning habitat to fishes. River managers have attempted rehabilitation of spawning habitat with river restoration, spawning habitat rehabilitation and dam removal, but often neglect well-established conceptual or predictive models of hydrogeomorphic and ecological processes. Project failure is not unusual and success can be difficult to accurately assess due to inadequate monitoring and unclear objectives. The scientific community has suggested a plethora of improved approaches to river restoration but little attention has been given to spawning habitat rehabilitation or providing detailed design methodologies. In many regulated rivers, complete restoration of geomorphic, hydrologic and ecological processes necessary for maintaining spawning habitat may not be possible. However, it is hypothesized that quality and availability of spawning habitat may be realistically improved upon with spawning habitat rehabilitation if a science-based approach is used. SHIRA (acronym for Spawning Habitat Integrated Rehabilitation Approach) was developed as a science-based framework for reach-scale rehabilitation of salmonid spawning habitat in regulated rivers. SHIRA relies on a mix of conceptual and numerical models to provide predictive and explanatory insight into the design and planning process. It is argued that application of such models can not only improve the outcome of rehabilitation projects, but also serve to further test and evaluate underlying scientific theories against the rigors of real-world