Similar drum screen and bypass designs were used at two large diversion canals where outmigrating salmon and steelhead are to be protected. Construction of the Chandler Canal Screens (and numerous other screens in the Yakima Basin), in south-central Washington state, occurred in the middle and late 1980s. Many of the same design criteria were employed for a drum screen facility at the Tehama-Colusa Canal, on the Sacramento River system in north-central California state, which was completed in early 1990. This is the largest drum screen facility for the protection of juvenile anadromous fish in existence. The functional designs of these two screen and bypass facilities are examined herein. Similar and diverse aspects at each site are described, with comments on biological and technical considerations.