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Home  Infocentre Guidelines & Factsheets Freshwater Intake End-of-Pipe Fish Screen Guideline
2.0 Guideline Objective
The objective of the guideline is to provide a National
standard-of-practice and guidance for end-of-pipe fish screens at freshwater
intakes to prevent potential losses of fish due to entrainment or impingement.
Entrainment occurs when a fish is drawn into a water intake and cannot
escape. Impingement occurs when an entrapped fish is held in contact
with the intake screen and is unable to free itself. The severity of
the impact on the fisheries resource and habitat depends on the abundance,
distribution, size, swimming ability, and behaviour of the organisms
in the vicinity of the intake, as well as, water velocity, flow and depth,
intake design, screen mesh size, installation and construction procedures
and other physical factors.
The Freshwater Intake End-of-Pipe Fish Screen
Guideline deals exclusively with the sizing and design of
fixed screens that are often placed at the end of a pipe used to extract
water up to 0.125 m3/s, or 125 litres per second
(L/s) (i.e., 2000 US gallons per minute (US gpm)). The guideline
is intended for use in addressing fish screens for small permanent
and temporary withdrawals for irrigation, construction, small municipal
and private water supplies, etc. It is not intended for application
to hydroelectric or canal screen designs; however, such proposals can
be considered by regulatory agencies on a site-specific basis. The
guideline focuses on the technical aspects of intake screens and the
protection of fish rather than on policy, legislation, or environmental
assessment processes and their application. This guideline has been
developed to provide protection of freshwater fish with a minimum fork
length of 25 mm (approximately 1 inch) since most eggs
and fish larvae remain in bottom substrates until they reach the fry
stage (i.e., 25 mm fork length).
Other designs, in addition to intake screens, may be appropriate to
address fish and fish habitat protection associated with water withdrawals.
Such proposed designs should be addressed with the appropriate regulatory
agencies on a site specific basis.
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