Laboratory Evaluation of an Aquatic Filter Barrier for Protecting Early Life Stages of Fish at Water Intakes
Jonathan L. Black, Timothy W. Hogan, Gregory S. Allen, Elgin S. Perry, and Kent D. Zammit
Abstract.—Aquatic Filter Barrier (AFB) is a permeable fabric material used to reduce the entrainment of ichthyoplankton at water intakes. To determine the potential for this material to protect a wide range of species, we evaluated the retention and survival of the early life stages of common carp Cyprinus carpio, rainbow smelt Osmerus mordax, white sucker Catostomus commersonii, striped bass Morone saxatilis, and bluegill Lepomis macrochirus exposed to AFB fabric in the laboratory. Twelve flow-through testing apparatuses were used in a closed-loop system to evaluate two flow rates (0.04 L/min/cm2) and 0.08 L/min/cm2) and three sizes of fabric perforation (0.5, 1.0, and 1.5 mm) with each species. The results indicate that, with one exception (pair-wise comparison of bluegill survival between 1.0-mm and 1.5- mm perforations; p = 0.0481), survival of organisms was not significantly correlated (p ≤ 0.05) to either flow rate or perforation size. Retention of organisms decreased significantly with increasing flow rate for one species of fish (pair-wise comparison of rainbow smelt between 0.04 and 0.08 L/min/cm2; p = 0.0084). In addition, larger perforation sizes resulted in significant decreases in retention for three of the test species (common carp, rainbow smelt, and striped bass; p ≤ 0.05). Consequently, the potential effectiveness AFB material is reduced by the use of larger perforation sizes. Provided that the material can be maintained and perforation sizes remain small (0.5 mm), AFB should prevent the entrainment of the majority of the organisms of the species tested in the laboratory.