The Columbia River used to host returns of nearly 9 million salmon every year, led by the largest returns in the world of Chinook salmon (4.4 million fish). But construction of multiple large dams on various tributaries and the Columbia River itself, eliminated salmon from vast tracts of rivers above impassable dams, and also had a serious effect on salmon survival in the remaining areas. Hydroelectric dams have a major impact on the passage of young salmon heading out to the ocean, since some do not survive passage through their electricity-generating turbines. A new review now highlights all of the screening mechanisms designed over more than 30 years in the Columbia River, intended to ensure that outmigrating salmon do not pass through the turbines. One of the key lessons learnt is to first model fish behavior under different river speeds before designing new screening systems to divert salmon around the turbines. The new work was led by SAFS affiliate professor John Williams and by Michael Gessel, Northwest Fisheries Science Center (retired), and appears in Marine Fisheries Review.