Biological Opinions - Bureau of Reclamation

term and localized and because fish are salvaged, this activity is unlikely to result in significant
adverse effects to LRS and SNS.
8.4.5 Effects of Maintenance to Other Project Canals, Laterals, and Drains
Nearly all Project canals, laterals, and drains are dewatered at the end of irrigation season, as late
as November for canals in California (USBR 2012). Canals remain dewatered until the
following spring (as early as late March) except for the input of localized precipitation-generated
runoff. Reclamation has proposed a conservation measure for salvaging suckers at specific
locations, as described in section 4.5.1 of the BA (USBR 2012), in an effort to minimize effects
associated with dewatering canals. Past efforts have shown that salvage is practicable in some
locations, but numbers of salvaged suckers are highly variable among years and sites (Taylor and
Wilkens 2013). Some canal maintenance occurs during the irrigation season, such as removal of
vegetation from trash racks at water control structures, but these temporary activities are only
anticipated to cause short-term avoidance responses by suckers (USBR 2012).
Most canal, lateral, and drain maintenance occurs while canals are dewatered, and includes
removal of sediment, vegetation, concrete repair, and culvert/pipe replacement (USBR 2012).
Gates, valves, and equipment associated with canals and facilities are exercised before and after
the irrigation season (before April and after October). In the past, these activities have typically
occurred after dewatering the canals and fish salvage of Project canals. Some activities, such as
culvert and pipe replacement, may temporarily increase sediment transportation. Based on the
presence of suckers in some Project canals (Kyger and Wilkens 2011b, 2012), adverse impacts to
suckers are anticipated as a result of seasonal canal dewatering and routine maintenance on canal
infrastructure. Most impacts, such as increased sedimentation, are temporary and result in stress
for fish. Other impacts include mortality through long-term stranding, such as when canals are
dewatered and pools become disconnected. Fish salvage of the remaining pools following
dewatering has prevented mortality losses of approximately 100 to 1,000 juvenile suckers yearly
since 2008 (Kyger and Wilkens 2012b, Taylor and Wilkens 2013).
Fish salvage likely removes a fraction of the LRS and SNS that remain in canals that are
dewatered at the end of the irrigation season, especially when the canals are drained late in the
season and become covered by ice. Additionally, large numbers of gulls forage in the canals
once water levels are low, and small suckers are likely among the prey caught by the birds.
Therefore, there is likely to be substantial mortality of suckers associated with dewatering the
canals. Because Reclamation proposes to relocate adult suckers from Lake Ewauna and put
them into UKL where they can reproduce, and proposes to fund a controlled-propagation
program, the effects of entrainment and mortality in canals will be minimized. It is also
anticipated that the adverse effects of these operations will be minimized by salvage operations
where suckers are moved to waters where they are likely to survive.
8.4.6 Effects of Right-of-way and Access Maintenance
Gravel is periodically added to roadbeds or boat ramps (e.g., at Clear Lake), and roadbeds are
periodically graded (USBR 2012). Right-of-way and access maintenance may temporarily cause
sedimentation into adjacent waterways, principally canals. The effects of sedimentation and
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