Eric Krebs, Alissa M. Muggli, Joseph M. Barnes, Michael E. Barnes
Water inlet structures to rearing units at fish hatcheries are used to maintain continuous water flow, prevent the introduction of undesirable organisms and organic debris, and deter escapement by the fish being reared. This paper describes a novel pond water inlet structure that not only kept the water flowing unimpeded, but required considerably less labor to maintain than other designs. This relatively simple aluminum structure consisted of a collar for attachment to the inflow pipe and a terminal splashplate. The splashplate was perpendicular to the inflow pipe during normal operations to both prevent fish from jumping into the inflow pipe and aerate the incoming water. The splashplate was designed to swivel upward to allow for the efficient removal of any debris, such as branches or leaves. Use of the inlet structure consistently increased incoming dissolved oxygen levels, which were as low as 4.75 mg/L, to over 9.0 mg/L. Increased efficiencies during hatchery operations can be realized by using this inexpensive and relatively easy-to-construct inlet structure.