Presenter/s: Joe Wheaton
Symposium Session: 2020 - 04 Observe Stage 0
Topics covered: _other, beavers, instream structure (culvert/bridge/dam), and stream
The scope of riverscape degradation far exceeds the modest footprint and scalability of most traditional restoration techniques with expensive price tags. Modern restoration practice borrows from a design process and logic entirely from engineering practice.
Low-tech process-based restoration of riverscapes
provides a potentially scalable solution that could rival the scope of degradation, but requires a fundamentally different and more efficient design approach drawing on physical and ecological principles. In this presentation we present riverscapes restoration principles and describe a robust, and rigorous design process that is agile enough to be carried out at the reach-scale within hours to day(s), as opposed to weeks to months. While individual low-tech, hand-built structures are specified in the design, the focus is at initiating and promoting processes at the “complex-scale” (a collection of structures), and these complexes help keep a focus on improving conditions at the reach scale. Unlike most designs, the focus here is not on stability of the structures, but on the processes and dynamics they are designed to initially mimic, quickly promote and eventually sustain. Key processes in structurally-starved riverscapes we focus on are wood accumulation and beaver dam activity. Examples from projects throughout the western US will be highlighted to show how the design process plays out. The upshot is that the footprint of restoration for the same amount of design effort can spent 10’s to 100’s of miles instead of 100’s to 1000’s of feet.