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A Lift for Fish
The 51 species of fish that move downstream through the Delta may benefit from a new designed facility to help them avoid being pulverized in the powerful export pumps. The facility is designed to test technology that could be implemented at the state and federal pumping facilities and perhaps ultimately replace the existing Tracy Fish Collection Facility.
When it began operating in 1957, the Tracy facility was considered state-of-the art. Over the years as fish were all too often sacrificed rather than salvaged, many inter-agency efforts took place to improve the facility, most with little success. Small fish like Delta smelt and splittail continued to be particularly vulnerable, slipping through the facility's louvers and ending up in the pumps rather than the Delta.
The test facility, which will likely be located across the Delta-Mendota Canal from the Tracy facility, will include a channel with screens and louvers as well as one or two bypass channels that use both "fish-friendly" lifts and gravity flow systems to move fish. Both the state and federal facilities use the gravity system now, says Mike Nepstad with BurRec, which passes water and fish through a series of screens, all generally headed in a downhill direction. The fish end up being dumped into a deep holding tank, where they are then hauled out and trucked downstream of the pumps to a safe release spot. The process is very stressful for the fish and there is a high mortality rate.
In contrast, the proposed new "fish-friendly" lift method would pump incoming water (and fish) several feet above ground level, and then carry the fish through a series of screens (all at ground level) that will remove debris and sort the fish according to size; the test facility will include smaller mesh screens that will filter much smaller fish than the existing facility. Ultimately, the fish will end up in a holding tank at ground level, possibly located in the back of a truck, all in an effort to decrease the amount of handling-and subsequent stress-to the fish.
The ultimate goal, says Charles Liston, Research Director for the test facility, is to save all healthy fish 20 mm and larger. Although no exact figures of losses are available for the current facility, says Liston, any fish that end up in the canals (rather than being salvaged and taken to a safe release spot) are "100% lost from the Delta."
BurRec's Denver Technical Service Center, which recently created "Crabzilla" (a "escalator" for mitten crabs that effectively removes them from the holding tanks) designed the test facility. BurRec hopes to begin construction of the test facility in the summer of 2001, with a completion date of 2003. The facility may remain a test facility, says Nepstad, or be converted to full production, depending on its success. Contact: Mike Nepstad (916)978-5204, or Charles Liston, www.mp.usbr.gov/tftf/ LOV
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