Wynoochee Dam Water Temperature Control Study

Source: https://erdc-library.erdc.dren.mil/jspui/ The US Army Engineer Waterways Experiment Station was tasked with evaluating the water temperature release capabilities of a proposed hydropower intake structure at Wynoochee Dam near Montesano, WA. The existing dam structure has passageways for juvenile fish migrating downstream and has flexible operation capabilities due to multilevel ports to meet downstream target temperatures. The hydropower developers have proposed a single wet well intake structure with two variable-opening gates. The study objective was to demonstrate the ability of the proposed structure to meet water temperature objectives at least equal to that of the existing structure. All objectives were accomplished by modifying and using the one-dimensional thermal simulation model, WESTEX. After verification of WESTEX to 2 years of historical temperature release data, prediction runs were made using an assumed range of intake loss coefficients and withdrawal angles for 3 years of data. The study concluded that the combination of the existing and proposed structures can meet downstream target temperatures as well as the existing structure alone.