Ice Harbor Spillway dissolved gas field studies : before and after spillway deflectors

Abstract

Abstract: Based on the results of the Dissolved Gas Abatement Studies, spillway deflectors were adopted for Ice Harbor as a measure to reduce the total dissolved gas (TDG) production during spill operations. Three field studies were conducted at the Ice Harbor Spillway on the lower Snake River to characterize the effects of spill operations on TDG in the Snake River. The first two studies examined TDG production for the original spillway design. The third study characterized TDG production with flow deflectors installed on the spillway face. TDG was significantly reduced for nearly all spill operations with deflectors in place. TDG near the stilling basin was reduced from approximately 150% to approximately 124%. TDG at end of the navigation guide wall was reduced from 135% to 114% for similar operating conditions.