Abstract
Pacific lamprey is an ancient anadramous fish that has declined in parallel with Pacific salmon. The focus on recovery within the Columbia River has led to the development of fishways specific for adult Pacific lamprey passage at dams. These novel structures exploit a natural and unusual climbing behavior of Pacific lamprey that allows them to ascend very steep slopes. The structures have been installed parallel to the existing fishways at several locations at Bonneville Dam. Each Lamprey Passage Structure (LPS) is unique because of the retrofit application. Here, I describe characteristics used in past LPS designs and criteria used to develop a new LPS at the Bonneville Dam Washington Shore fishway. LPS structures are composed of three major components, climbing ducts, rest boxes and traversing ducts. The traversing duct is a low slope (S=0.0035) rectangular channel with subcritical flow; while the climbing duct is a steep slope (S=1.0) structure with thin supercritical flow.
We developed a hydraulic model of both duct types. The result of the model is a series of operating curves for varying widths and slope that predict discharge and velocity based on flow depth. We also determined an appropriate roughness for the LPS systems based on reported operating conditions. The flow conditions within the ductwork are steady and uniform. In contrast, there are unique features implemented within each LPS that may present complex and challenging hydraulic conditions. Using the recent system installed at The Bonneville Dam Washington North Shore Fishway as a case study, we catalog the different features and their hydraulic conditions.
Pacific lamprey research and recovery efforts are occurring at a rapid pace. The complexity of researching and addressing the problems uncovered in real time is tedious. A large number of studies and modifications have been undertaken to improve passage of adult lamprey at Bonneville Dam. Integrating such diverse sets of information types in a spatially explicit context is a common challenge in many applied research settings. We developed a collaborative, visual model, which integrated the current information on Pacific lamprey with the structural elements of the Washington Shore Fishway to improve recovery efforts. The tool is a 3D visual model with overlaid and integrated information creating a fish passage "wiki". Stakeholders will be able to investigate different aspects of Pacific lamprey recovery including research results, current and past modifications, and archive photos, all within the structural context of the fishway. The wiki aspect describes a potential for transparency and crowd sourced maintenance of the information. Stakeholders can use the fish passage wiki for both dissemination and synthesizing information, and prioritizing future management and conservation actions. The 3D-wiki tool is aimed at developing a more comprehensive understanding of the difficulties facing Pacific lamprey passage within the Columbia River basin.