Biological Opinions - Bureau of Reclamation

functioning floodplains that fail to support healthy riparian recruitment. Winter rearing areas
suffer from minimal recruitment of large woody debris and stream habitat simplification. Many
stream reaches within the Upper Klamath are either lacking riparian forest altogether or lack
complex, late seral forest. Grazing and flow impairments along the mainstem and in tributaries
such as Horse, Humbug, Willow, and Cottonwood creeks have severely degraded riparian
function.
11.3.2.2 Juvenile Migration Corridor
In the Upper Klamath River reach, juvenile migration corridors are degraded because of
diversion dams, low flow conditions, poorly functioning road/stream crossings, disease effects,
high water temperatures and low water velocities that slow and hinder emigration or upstream
and downstream redistribution. The unnatural and steep decline of the hydrograph in the spring
likely slow the emigration of coho salmon smolts, speed the proliferation of fish diseases, and
increase water temperatures more quickly than would occur otherwise. Disease effects,
particularly in areas such as the Trees of Heaven site (RM 170), likely have a substantial impact
on the survival of juvenile coho salmon in this stretch of river. Thus, the conservation role of the
juvenile migration corridor of the Upper Klamath River reach is not properly functioning.
11.3.2.3 Adult Migration Corridor
The current physical and hydrologic conditions of the adult migration corridor in the Upper
Klamath River reach are likely properly functioning in a manner that supports the conservation
role of the adult migration corridor. Water quality is suitable for upstream adult migration, and
with implementation of flows based on the RPA in NMFS’ BiOp for Reclamation’s Klamath
Project (NMFS 2010a), flow volume is above the threshold at which physical barriers to
migration are likely to form.
11.3.2.4 Spawning Areas.
Coho salmon are typically tributary spawners. However, low numbers of adult coho salmon
annually spawn in the Upper Klamath River mainstem. Upstream dams block the transport of
sediment into this reach of river. The lack of clean and loose gravel diminishes the amount and
quality of salmonid spawning habitat downstream of dams. This condition is especially critical
below IGD (FERC 2007). Water temperatures and water velocities are generally sufficient in
this reach for successful adult coho salmon spawning. Gravel augmentation implemented under
the PacifiCorp habitat conservation plan will partially restore spawning habitat in the Upper
Klamath River reach, particularly between IGD and the confluence with the Shasta River.
Coho salmon spawning, which requires suitable substrate conditions, has been observed in
Bogus, Horse, Beaver, Canyon, Grider and Seiad Creeks, as well as in small sections of the
mainstem Upper Klamath River within the first several miles downstream of IGD. Downstream
of IGD, channel conditions reflect the interruption of sediment flux from upstream by reservoir
capture and the eventual re-supply of sediment from tributaries entering the mainstem Klamath
River (PacifiCorp 2004). Upstream dams block the transport of sediment into this reach of river.
The lack of clean and loose gravel diminishes the amount and quality of coho salmon spawning
220