The Department of Fish and Game has been protecting fish with fish screens since it was created, and currently has three screen shops located in Yreka, Red Bluff and Elk Grove. There are two basic types of fish screens. These attempt to keep fish out of the water diversion by causing the fish to swim away from the site. Commonly used materials include perforated plate, woven wire mesh and welded wedge wire. Presently, these are the only fish screens that meet DFG fish screen criteria.
Fish screens are necessary to prevent the loss of fishery resources at water diversion sites.
Instead, several once-abundant fish populations are now listed as either threatened or endangered under either the Federal Endangered Species Act, or the California Endangered Species Act. State law provides the authority for the installation of fish screens. This authority is described in several sections of the Fish and Game Code. Screening requirements vary, depending on the age and size of the diversion. For diversions constructed or modified since 1972, Fish and Game Code Section 6100 et.seq, apply.