Biological Opinions - Bureau of Reclamation

Table 7.4 Estimated external phosphorus loading to UKL from various sources (ODEQ 2002).
Source Area
Percent of
Drainage Area
Percent of Inflow to
UKL
Percent of External
Phosphorus Load
Sprague River 43 33 26
Williamson River 36 18 20
Wood River 4.0 16 19
Seven Mile Creek 1.1 6.5 9.0
Agricultural Discharges
Directly into UKL
1.1 2.9 11
Precipitation Input
Directly into UKL
2.8 7.0 2.7
Other Sources 16 14 11
7.10.1.5 pH
Because the Klamath River is a weakly buffered system (i.e., has typically low alkalinity 10) in summer. Extended
periods of pH greater than 9 have been associated with large summer algal blooms in UKL
(Kann 2010). On a daily basis, algal photosynthesis can elevate pH levels by up to 2 pH units
over a 24-hour period. Generally, pH in the reach from Link River Dam through the Keno
Reservoir increases from spring to early summer and decreases in the fall; however, there are
site-dependent variations in the observed trend. Peak values can exceed the Oregon Department
of Environmental Quality maximum of 9.0.
7.10.1.6 Algae
In UKL, algae, including blue-green algae, are dominated by large summertime blooms of AFA.
High (i.e., near 300 µg/L) summer chlorophyll-a concentrations in the Keno Reservoir/Lake
Ewauna are due to large populations and associated nutrients of algae, predominantly AFA,
entering the Klamath River from UKL in summer (FERC 2007; Sullivan et al. 2008, 2009,
76