Graduation Date

Summer 2017

Document Type



Master of Science degree with a major in Environmental Systems, option Environmental Resources Engineering

Committee Chair Name

Dr. Margaret Lang

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

Dr. Eileen Cashman

Second Committee Member Affiliation

HSU Faculty or Staff

Third Committee Member Name

Dr. Mark Henderson

Third Committee Member Affiliation

HSU Faculty or Staff

Subject Categories

Environmental Resources Engineering


This thesis presents the hydraulic characteristics and simulated passage efficiency of a hybrid pool-and-chute, vortex weir fishway designed by Michael Love & Associates. A physical 1:15 scale model was constructed and evaluated at an 8% slope over three prototype flow rates representing high and medium fish passage flows. The highest velocities and turbulent kinetic energy (TKE) values were concentrated along the fishway centerline at the high and medium flow rate and the pool sides showed lower velocities and TKE. Large eddies spin laterally and longitudinally throughout each pool. The velocity vector directions at the lowest flow rate measured differed from the two higher flow rates with larger, more pronounced eddies on the pool sides.

The fishway’s velocities and their spatial distribution were used to estimate passage success and fatigue level. A preliminary numerical model was created that simulates a steelhead or coho salmon ascending the fishway. This model uses observed size distributions for adult steelhead and coho from data presented in the literature and calculates each individually sampled fish’s passage time and percent fatigue. Two swim pathways were analyzed at both the high and medium flow rates. A thousand fish of each species were simulated ascending the fishway, and zero fish reached 100% fatigue under any scenario. Results indicate that ascension of the prototype fishway should not be energetically limiting for steelhead or coho salmon.

This model was also used to calculate the maximum fishway length (holding the original 30-feet width constant) over which zero fish reached 100% fatigue, assuming fish did not rest and recover from fatigue within the pools between weirs. Results indicate the fishway length could increase by an additional three pools and weirs or 37.5 feet without causing any fish in the sample distribution to reach 100% fatigue. Conservative fishway design would not recommend increasing the fishway length beyond the length where fish reach 100 F% to ensure an energetic factor of safety and account for potential behavioral or motivation delays. Further investigation into the nature of fish use of the new prototype fishway design could help calibrate the models presented in this thesis and increase the accuracy of the passage efficiency estimations.

Citation Style



Thesis/Project Location