Screen Types

Positive Barrier Screens

Rotary Drum Screenrotatingdrum



  • Proven fish protection
  • Self-cleaning by rotation
  • Passes debris downstream

  • Susceptible to direct hits from large debris
  • Large civil works required
  • Seals require significant maintenance
  • Susceptible to abrasions by sand – mesh requires periodic replacement
  • Need control to maintain submergence between 65% and 85%
Vertical Fixed Plate Screenverticalfixedplate



  • Easy to see
  • Mechanically simple
  • Can be installed on river’s edge – small screens
  • No bypass required
  • Can use profile wire
  • Mechanical/brush cleaning usually effective
  • Air burst cleaning system is on back side of screen
  • Cleaning is started by timer or head loss

  • Must be cleaned mechanically
  • Large bypass flows required
  • Brush arms can be damaged by large debris
  • Circular air burst cleaners do not clean entire screen
Vertical Traveling Screenverticaltraveling



  • Small screens can be installed on riverbank
  • Compact civil works
  • Self-cleaned by rotation
  • Jet sprays provide additional cleaning

  • Mechanically complex
  • Seals can be a problem
  • Make sure meets all NMFS criteria (old styles may not)
Non-Vertical Fixed Plate Screen – Coandanonverticalfixedplatecoanda



  • No moving parts
  • No bypass required if built in-river

  • Self-cleaning may not be reliable
  • Risk of fish injury/mortality on screen during low flow
  • Must raise and control water surface
  • Unreliable flow rate control
  • Adult upstream passage concerns
  • Potential issues with hydraulic gradients
Horizontal Screens – FCAhorizontalscreen


Eicher Screeneicher


Modular Inclined Screens


End-Of-Pipe (Pump) Intake Screensendofpipepumpscreennoaa


Fixed Cylindrical Screensfixedcylinder



  • Good option for deep intakes
  • Air burst cleaning system can be made to be effective
  • Some off-the-shelf models with water backwash systems meet NMFS criteria for active screens

  • Out of sight, out of mind
  • Need sweep velocity to transport debris from screen site
  • Air burst systems on large installations don’t always clean entire screen – especially the bottom
  • Long, stringy vegetation is a problem on small pump screens
Pump Screenspump


Passive Screens (not self-cleaned)




Selection Criteria

  • Only considered for use when site is not suitable for an active screen
  • Uniform approach velocity must be apparent from the conceptual screen design
  • Approach velocity not to exceed 0.2 ft/s
  • Combined rate of flow at the diversion site must be less than 3 cfs
Maintenance and debris management

  • A maintenance program must be approved by NMFS and implemented by the water user
  • Screen must be frequently inspected with debris accumulations removed, as site conditions dictate
  • Sufficient stream depth must exist at the screen site to provide for a water column of at least one screen radius around the screen face
  • Screen must be designed to allow easy removal for maintenance, and to protect from flooding
  • Debris load must be low
  • Sufficient ambient river velocity must exist to carry debris away from the screen face