California's Sacramento-San Joaquin River system drains the Central Valley and has been extensively developed to provide water to domestic, industrial, and agricultural users and to control floods. The system also provides essential habitat for several species of anadromous and resident fish, including chinook salmon Oncorhynchus tshawytscha and striped bass Morone saxatilis . This article describes three situations (Red Bluff Diversion Dam, the upper Sacramento River, and Delta diversions) in which bioengineering has been used, or will be used, to develop measures designed to protect fishery resources at water project features. In general, mitigation measures have not always been effective, partly because of poor communication among biologists, planners, and design engineers. There are indications in California that project planners are now more aware of fishery concerns and that this awareness will result in more effective engineering solutions to complex biological problems.