Fish-protection devices at unscreened water diversions can reduce entrainment: evidence from behavioural laboratory investigations

Abstract

Water diversion can pose a risk to resident or migratory fishes, but fish-protection devices that reduce the entrainment of native fishes and maintain normal diversion activities exist.

Biology and life history of Green Sturgeon (Acipenser medirostrisAyres, 1854): state of the science

“…There are hundreds of unscreened water diversions in the Sacramento River and Sacramento‐San Joaquin Delta (Herren and Kawasaki, ; Mussen et al., ). Laboratory testing indicated that young (<30 cm TL) GRS contacted and were impinged on screens two times more frequently than young WS (Poletto et al., ,b). However, a study of fish entrainment at an unscreened diversion in the Sacramento River did not report any GRS, even though individuals of other fish species ranging 9–59 mm FL were observed during July 2000 and 2001 (Nobriga et al., ).…”

Hydraulics Near Unscreened Diversion Pipes in Open Channels: Large Flume Experiments

“…We investigated the relationship between the hydraulic fields surrounding an unscreened diversion pipe and fish swimming behavior under relevant diversion and channel flow characteristics, using a large flume at the J. Amorocho Hydraulics Laboratory (JAHL) of University of California, Davis. Results of the fish behavior and entrainment risks near unscreened water diversions with and without various fish protection devices were reported recently by Mussen et al (2013Mussen et al ( , 2014aMussen et al ( , b, 2015 and Poletto et al (2014Poletto et al ( , 2015. Mussen et al (2013) evaluated juvenile Chinook salmon (mean fork lengths between 12.5 and 13.3 cm) entrainment risk and their behavioral responses to an unscreened diversion pipe under various channel flow and diversion rate conditions during day, night, and in turbid water conditions.…”

“…Most of the smaller sized irrigation pipes used in these waterways are currently unscreened (CalFish, ). These unscreened water‐diversion pipes are potentially harmful to migrating and resident fishes, including several threatened or endangered species (Turnpenny et al ., ; Nobriga et al ., ; King and O'Connor, ; Gale et al ., ; Kimmerer, ; Grimaldo et al ., ; Mussen et al ., ; and Poletto et al ., , ). Fish entrained into these diversions (drawn in with water inflow) are either killed directly by physical damage from the pumps, or indirectly through stranding in the seasonally irrigated canals, ditches, and fields supplied by the water diversions (Mussen et al ., ).…”

Experimental evaluation of the effect of a light-emitting diode device on Chinook salmon smolt entrainment in a simulated river

“…A 0.15-m/s sweeping velocity was generated to simulate a river current, and a water withdrawal rate through the pipe of 0.57 m 3 /s. This set-up simulated ecologically and hydraulically relevant conditions common to the Sacramento river and near-identical set-ups have been utilized in several experiments investigating Chinook salmon smolt and green sturgeon Acipenser medirostris (Ayres, 1854) behavior and entrainment (Mussen et al, 2013(Mussen et al, , 2014a(Mussen et al, , b, 2015Poletto et al, 2014Poletto et al, , 2015Ercan et al, 2017). A detailed description of the flume and its operational methods can be found in Mussen et al (2013).…”

“…These divert, in an average year, more than 40% of the rivers' flow to supply 80% of the agricultural and urban water uses (Hanak et al, 2011;CDWR, 2014). These diversions pose a significant entrainment threat to fish species, including outmigrating Chinook salmon [(Oncorhynchus tshawytscha, (Walbaum, 1792)] smolts, as fish can either get impinged or inadvertently drawn with the water and transferred into machinery and irrigation ditches (Coutant & Whitney, 2000;Herren & Kawasaki, 2001;Kimmerer, 2008;Mussen et al, 2013Mussen et al, , 2014aMussen et al, , b, 2015. These processes are one of the several contributing factors to the decline of Chinook salmon in California's central valley, USA (Moyle et al, 2011).…”