Screen Types

Positive Barrier Screens

Rotary Drum Screen	Advantages Proven fish protection Self-cleaning by rotation Passes debris downstream	Disadvantages 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 Screen	Advantages 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	Disadvantages 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 Screen	Advantages Small screens can be installed on riverbank Compact civil works Self-cleaned by rotation Jet sprays provide additional cleaning	Disadvantages Mechanically complex Seals can be a problem Make sure meets all NMFS criteria (old styles may not)
Non-Vertical Fixed Plate Screen – Coanda	Advantages No moving parts No bypass required if built in-river	Disadvantages 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 – FCA
Eicher Screen
Modular Inclined Screens
End-Of-Pipe (Pump) Intake Screens
Fixed Cylindrical Screens	Advantages 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	Disadvantages 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 Screens

Passive Screens (not self-cleaned)