Designing Rivers With Multiple Scales of Channel and Floodplain Variation To Yield Diverse Processes and Ecosystem Services (#74)
River restoration is a young discipline with high uncertainty in hydrogeomorphic response and ecosystem benefits. A central problem with current practice exists due to the mismatch between the understanding of rivers at the reach scale versus the occurrence of ecosystem services at much smaller meso- and micro-habitat scales. Process-based and descriptive river classifications aid practitioners with specifying reach-scale metrics, such as slope, bankfull width, sinuosity, entrenchment, and median particle size. However, the design of landforms and hydraulic structures nested within reaches for aquatic and riparian benefits is largely expert-based and lacking a systematic spatial organization. Recently, a new river corridor design paradigm termed “synthetic river valleys” has been developed that begins with reach-scale metrics, but then multiple scales of channel and floodplain variation are objectively layered on to achieve diverse ecosystem services. Example types of variation include asymmetric undulating valley widths, bed elevations, and planform alignments. Synergy between different types and scales of variation can be controlled to achieve different physical mechanisms and ecosystem services, aided by evaluation of the longitudinal covariance among pairs of undulating variables. To gain these benefits without making the practice of channel design unduly complicated, a new user-friendly software package has been developed that allows users to easily specify channel elements with simple dialogue boxes within a flowchart. Then a design is rendered in 3D so the user can orbit and fly through the landscape to evaluate it, enabling fast iterative design. Final products may be exported as a raster for analysis and construction.