Biological Opinions - Bureau of Reclamation

esource needs as they grow, and 3) competition with other individuals. The movements of
stream-dwelling salmonids have been the subject of extensive research (Chapman 1962,
Edmundson et al. 1968, Fausch and White 1986, Gowan et al. 1994, Bell 2001, Kahler et al.
2001). Although many juvenile salmonids are territorial or exhibit limited movement, many
undergo extensive migrations (Gowan et al. 1994, Fausch and Young 1995). For example,
salmonid fry often disperse downstream from headwater spawning sites. Additional movements
can occur as intraspecific competition for resources causes the additional dispersal of subordinate
individuals (Chapman 1966, Everest and Chapman 1972, Hearn 1987). Juvenile salmonids are
likely to move in response to growth or simply because environmental conditions such as water
depth or velocity are no longer suitable (Edmundson et al. 1968, Leider et al. 1986, Lau 1994,
Kahler et al. 2001).
e. Fish Screens
Water diversions can greatly affect aquatic life when organisms are entrained into intake canals
or pipes -- an estimated 10 million juvenile salmonids were lost annually through unscreened
diversions in the Sacramento River alone (Upper Sacramento River Fisheries and Riparian
Habitat Advisory Council 1989). Once entrained, juvenile fish can be transported to less
favorable habitat (e.g., a reservoir, lake or drainage ditch) or killed instantly by turbines. Fish
screens are commonly used to prevent entrainment of juvenile fish in water diverted for
agriculture, power generation, or domestic use.
Fish screens substantially decrease juvenile fish loss in stream reaches where surface flow is
regularly diverted out of channel. Surface diversions vary widely in size and purpose, from
small gravity fed diversion canals supplying agricultural water to large hydraulic pumping
systems common to municipal water or power production. All screening projects have similar
goals, most notably preventing fish entrainment into intake canals and impingement against the
mesh screen. To accomplish this, all screening projects will follow CDFW and NMFS
guidelines, which outline screen design, construction and placement, as well as designing and
implementing successful juvenile bypass systems that return screened fish back to the stream
channel.
Fish screen projects will reduce the risk for fish being entrained into irrigation systems. Welldesigned
fish screens and associated diversions ensure that fish injury or stranding is avoided,
and fish are able to migrate through stream systems at the normal time of year.
11.4.2.4 Summary
Although Reclamation’s funding for restoration activities will likely result in minor and shortterm
adverse effects during implementation, NMFS expects the suite of restoration activities will
result in longer term improvements to the function and role of critical habitat in the action area.
Based on information on the PacifiCorp’s coho enhancement fund (PacifiCorp 2013), NMFS
estimates approximately four to six restoration projects will be implemented each year
throughout the mainstem Klamath River and major tributaries. Approximately 71 percent of the
four to six restoration projects each year will be successful at increasing the conservation value
for coho salmon fry and juveniles.
286