Leslie Hanna. 2010. "ISI Cylindrical Screen Performance". Bureau of Reclamation, Report Number PAP-1016.
Abstract: Fish screens are required on water diversion intakes in many locations to prevent entrainment of fish and other aquatic species. Maintaining the screen surface in a clean condition is imperative for water diversion and aquatic species protection. Screens are generally designed with cleaning devices that remove impinged aquatic debris off the screen surface. Quagga mussels, an invasive species, have recently been found in a number of locations in the western United States. Quagga mussels are filter feeders that attach in large numbers to almost any surface, and would likely find fish screens ideal. Reclamation’s Research Office is funding a study to investigate the impact that Quagga mussels could have on operation of common styles of fish screens. The study presented herein provides baseline data on the performance of the ISI (Intake Screens Inc.) cylindrical fish screen. The ISI screen is one of several screens that have been selected to be evaluated in a field study of screen performance where Quagga mussels are present in large numbers. Resource agencies have adopted standards that require that screens meet a maximum approach velocity criteria ranging from 0.2 ft/s to 0.40 ft/s depending on the fish species residing in a given area (i.e. velocity measured perpendicular to the screen surface). These screens must be able to perform within this set criteria despite having to shed heavy debris loads. Figure 1 ISI hydraulically operated cylindrical screen inside test flume. It is also important for screen manufacturer’s to produce screen designs that provide uniform approach velocities in order to meet screen criteria guidelines while minimizing screen surface area or size required at a diversion. In order to accomplish this objective an improved understanding of fish screen hydraulics is needed. As a result, the Hydraulics Investigations and Laboratory Services Group at the U.S. Bureau of Reclamation (Reclamation) in Denver has conducted testing to study the performance of cylindrical fish screens for providing an effective positive barrier for fish exclusion. In this study two 30-inch diameter cylindrical screens were loaned to Reclamation by ISI for testing and performance evaluation (figure 1). These screens have a unique cleaning system (patented) that uses an internal and external brush system. The screens were loaned to Reclamation to determine headloss through the screen and to determine the level of uniformity of approach velocities.
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