Low-Tech Process-Based Restoration of Riverscapes: Design Manual (1) (in English)
Synopsis "Low-Tech Process-Based Restoration of Riverscapes: Design Manual (1) (in English)"
The purpose of this design manual is to provide restoration practitioners with guidelines for implementing a subset of low-tech tools--namely beaver dam analogues (BDAs) and post-assisted log structures(PALS)--for initiating process-based restoration in structurally-starved riverscapes. While the concept of process-based restoration in riverscapes has been advocated for at least two decades, details and specific examples on howto implement it remain sparse. Here, we describe 'low-tech process-based restoration' as a practice of using simple, low unit-cost, structural additions(e.g. wood and beaver dams) to riverscapes to mimic functions and initiate specific processes. Hallmarks of this approach include:An explicit focus on the processes that a low-tech restoration intervention is meant to promote.A conscious effort to use cost-effective,low-tech treatments (e.g., hand-built, natural materials, non-engineered,short-term design life-spans) because of the need to efficiently scale-up application.'Letting the system do the work', which defers critical decision making to riverscapes and nature's ecosystem engineers (beaver).Importantly,the manual conveys underlying principles guiding use of low-tech tools inprocess-based restoration in systems impaired by insufficient structuralcomplexity. Although intended to be simple, low-tech restoration still requiressome basic understanding of watershed context, riverscape behavior and channelevolution, and careful planning. The manual provides interested practitionerswith sufficient conceptual and applied information on planning, design,permitting, construction and adaptive management to get started, as well asreferences to additional information and resources. Detailed design andconstruction guidance is provided on two effective low-tech tools: 1) beaverdam analogues (BDAs) for mimicking beaver dam activity, and 2) post-assistedlog structures (PALS) for mimicking wood accumulation in riverscapes. Throughoutthe manual, readers are reminded that the structures themselves are not thesolution, but rather a means to initiate specific, desirable processes.Ultimately, embracing the design principles will help practitioners betterunderstand the 'why' behind structural interventions and allow for moreefficient and effective riverscape restoration.
