Graduation Date

Summer 2021

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

Antonio Llanos, P.E.

Third Committee Member Affiliation

Community Member or Outside Professional

Subject Categories

Environmental Resources Engineering


Tide gates are common hydraulic structures located throughout coastal and estuarine areas that prevent tidal waves from flooding previously converted tidally influenced areas. As restoration efforts increase, more “fish-friendly” tide gates that allow for larger openings and longer opening periods are being installed to improve habitat for threatened or endangered species. The purpose of this thesis was to determine discharge and head loss coefficients for traditional and side-hinged tide gates that could be inputs for hydraulic models and improve tide gate sizing and design. The study sites included Gannon Slough and US 101 Slough in Humboldt, California that represented a traditional, top-hinged gate and a side-hinged gate, respectively. Discharge, water levels and angle measurements of the gates were all collected during gate openings. These values were used to determine discharge coefficients for Gannon Slough, head loss coefficients for US 101 Slough, and analyze fish passage through each site. At Gannon Slough, discharge coefficients ranged between 0.12 and 0.86. US 101 Slough’s head loss coefficients ranged between 1.09 and 16.07. Both hydraulic parameters were compared to angle opening and discharge in attempt to identify patterns that could be related to different phases throughout the opening. However, the parameters did not produce distinguishable values related to the openings. Future recommendations include increasing measurements during gate measurements and an exploration at various flow events.

Citation Style



Thesis/Project Location