Water Withdrawal
Best Practices

A Fish Habitat Permit for water withdrawal will include requirements to minimize impacts to fish and their habitats. These may include but are not limited to:

Properly screened box intake
  • Water intakes must be screened to avoid injury to fish.
  • Typically screen openings may not exceed 0.25 inches (0.10 inches or less in areas with sensitive fish species or life stages), and water velocity at the screen/water interface may not exceed 0.5 feet per second when the pump is operating.

    Quick Tip: To test whether you are meeting the velocity requirement, hold a plastic bag next to the screen intake and the bag should not get sucked up against the screen.

  • Pump intake screens should be periodically checked during operations to ensure that the screening has not collapsed, there are no breaks/gaps in the mesh, and the screen has not become blocked by debris.

One simple method to screen a 30-gallon-per-minute or less pump for use in a fish stream is to drill 3/32-inch holes throughout a sealed five-gallon bucket and then center the intake inside this bucket. For larger pumps, screens may be constructed from perforated plate or wedge wire/profile bar.

The Habitat Division Techinical Report No. 97-8 (PDF 2,558 kB) contains additional information on screening criteria for various species and life stages of fish as well as methods for design and fabrication of cylindrical water intakes.