NatureWater Lesson Plans
Water is removed from rivers for irrigation via pipes or ditches, called diversions. Salmon and steelhead migrate to the ocean when they are fry, and then swim back up the river as adults. During their migrations, they pass by the diversions. If they swim into them they end up in the fields, where they die. The Sacramento River has approximately 300 diversions between Redding and the Feather River. The large ones, such as the Tehema-Colusa Canal at the Red Bluff Diversion Dam, are screened. However, most of the small diversions are not yet screened. Other rivers also have unscreened diversions.
Install fish screens at all diversions. There are different types of screens for different types of diversions. Some are huge, like the ones at the Tehema-Colusa Canal. Others are small and fairly simple in design. Regardless of the design, the purpose of all fish screens is the same - to keep fish from swimming into irrigation canals.
Pictures of Fish Screens