Fish Screen Design Criteria


Intake screens are typically designed to protect fish from being entrained into a diversion AND to prevent them from being impinged on the screen surface.  This means that the screen openings must be small enough to keep the fish out and that there is enough screen area to allow the fish to swim away without injury.  There are also requirements for providing good hydraulic conditions, keeping the screens clean, and for siting them appropriately in a river, canal, or lake environment.

Several state and federal agencies have guidelines and design criteria for fish protection.  Generally the more conservative criteria will govern; however, there are variances and exceptions to these guidelines since each project is unique.  A well designed facility will also consider the pump or diversion requirements as well as operations and maintenance issues.

ISI’s engineers are familiar with the regulatory design requirements and are experienced in selecting an appropriate design for your new or retrofit project.  We can guide you through the complicated design issues and determine which options makes the most sense - even if an ISI screen is not the most appropriate option!

Below we have referenced several intake screen design criteria that may be applicable to your project.  Please review our project examples to see if your project has similar needs.  Please call us to assist.


Fish Screen Design Criteria Information and Program Links

Family Water Alliance - Sacramento Valley Fish Screen Program and Criteria


U.S. Bureau of Reclamation - Fish Protection at Water Diversions Design Manual


U.S. Forest Service - Pocket Guide to Screening Small Water Diversions (Draft)


National Marine Fisheries Service (NMFS) - California Fish Screen Passage and Screen Criteria


National Marine Fisheries Service (NMFS) - Northwest Fish Passage and Screen Criteria


U.S. Fish and Wildlife Service - Fish Passage Program Information


California Department of Fish and Game - Fish Screen Design Criteria


Oregon Department of Fish and Wildlife - Fish Screen Criteria and Grant Program Infomation:


Washington Department of Fish and Wildlife - Fish Screen Protection Screen Guidelines


Idaho Department of Fish and Game - Fish Screen Program Information


Canada Fisheries and Oceans - Guidelines for Intake End-of-Pipe Screens


U.S. Environmental Protection Agency - Cooling Water Intake Structure Regulations