The purpose of this passage and survival study was to estimate fish performance metrics associated with passage through Lower Granite Dam (LGR) for migrating yearling (CH1) and subyearling (CH0) Chinook salmon (Oncorhynchus tshawytscha) and steelhead smolts (O. mykiss, STH) in 2018. Researchers at the Pacific Northwest National Laboratory (PNNL) collaborated with the U.S. Army Corps of Engineers (USACE) Walla Walla District (CENWW), the University of Washington, and Mainstem Fish Research to conduct a 2018 study to estimate dam passage survival and other performance metrics for CH1, CH0, and STH at LGR.