Product Code Database
A fish screen is a barrier to prevent fish from swimming or being drawn into an aqueduct, cooling water intake, dam intake tower, or other diversion on a river, lake, reservoir, or waterway where water is taken for human use. It supplies debris-free water with limited harm to aquatic life.
Fish screens are typically installed to protect endangered species that would otherwise be harmed or killed when passing through industrial facilities such as steam electric power plants, hydroelectricity generators, oil refinery, , farm irrigation water and municipal drinking water treatment plants. However, many fish are killed or injured on screens or elsewhere in the intake structures.
Positive barriers are often effective at keeping aquatic organisms from entering a cooling system, but may also kill some by impinging them on the screens. Widely used barriers include:
The U.S. Environmental Protection Agency (EPA) has evaluated other barrier technologies and identified some as potentially effective, although not widely demonstrated (as of 2004):
Some screens are capable of protecting more than one species or type of life; others are designed to protect a single species of fish (for example, salmon) and are not necessarily effective at protecting other fish species. Additionally, some screens may effectively protect juvenile and adult fish, but not fish eggs and .EPA (2002). "National Pollutant Discharge Elimination System—Proposed Regulations to Establish Requirements for Cooling Water Intake Structures at Phase II Existing Facilities; Proposed Rule." . 2002-04-09.
The cost of a fish screen varies from thousands of US dollars for small, low-flow-rate screens to millions for very large custom-designed high-flow systems. Maintenance costs include repairs, removing trash, and adjusting screens for changes in stream conditions.
The U.S. Clean Water Act requires EPA to issue on industrial cooling water intake structures.Clean Water Act, Section 316(b), . The agency issued regulations for new facilities in 2001 (amended 2003),EPA. "National Pollutant Discharge Elimination System: Regulations Addressing Cooling Water Intake Structures for New Facilities." Final rule: 2001-12-18, Federal Register, 66 FR 65255. Amended: 2003-06-19, 68 FR 36749. and for existing facilities in 2014.EPA. "National Pollutant Discharge Elimination System—Final Regulations To Establish Requirements for Cooling Water Intake Structures at Existing Facilities and Amend Requirements at Phase I Facilities" Final rule. Federal Register, 79 FR 48300. 2014-08-15.
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