Biological Opinions - Bureau of Reclamation

September 30 of each year, delivery of water to the east side of the Project occurs primarily from
mid-April through the end of September. East side Project features are shown in Figure 3.2.
These two east side reservoirs store water to meet irrigation needs of the east side and prevent
flooding in and around Tule Lake. Water from Clear Lake and Gerber Reservoirs principally
serve Langell Valley Irrigation District, Horsefly Irrigation District, and private Warren Act
contract lands. However, water from return flows and accretions can be delivered to other
Project lands through the Lost River and Lost River Diversion Channel system. Irrigation water
on the east side is managed to minimize flow passing Harpold Dam, a Horsefly Irrigation District
facility. Water that does flow past Harpold Dam is used by irrigators or diverted into the Lost
River Diversion Channel, where it may be used on the west side of the Project or routed to the
Klamath River.
Water released from Clear Lake Reservoir primarily serves land west of the Lost River, and is
diverted into the West Canal through headworks located at Malone Dam, approximately 12 miles
(mi) (19 kilometers [km]) below Clear Lake. Only irrigation releases are made from Clear Lake
Dam unless required by an emergency situation. Emergency situations for Clear Lake and
Gerber Reservoirs may include, but are not limited to, flood control, dam failure, and inoperable
gates.
Water released from Gerber Reservoir primarily serves lands east of the Lost River, and is
diverted into the North Canal through a diversion structure on Miller Creek approximately 6 mi
(10 km) below Gerber Reservoir. The North Canal provides water to the Langell Valley
Irrigation District. During the irrigation season, no water is released into Miller Creek below the
diversion structure; however, return flows from irrigation of adjacent lands and dam leakage
provide some flow in Miller Creek. When irrigation water is not used, water flows down Miller
Creek to the Lost River.
The POR for hydrologic and Project data for this proposed action as it relates to the east side of
the Project is 1903 through 2012 for Clear Lake Reservoir, and 1925 through 2012 for Gerber
Reservoir. The POR includes a broad range of hydrologic conditions that likely encompasses the
range of future conditions that may occur within the 10-year period covered by the proposed
action.
Reclamation proposes to operate the east side of the Project as described below.
4.2.2.1 Clear Lake Operations
Under the proposed action, Clear Lake is generally expected to provide water sufficient to meet
irrigation demand, which is anticipated to be near the long-term average of approximately 34,000
acre-feet annually. Water is generally used between April 15 and September 30, with the outlet
at Clear Lake Dam typically opened on April 15 and closed on October 1. The average release
rate is approximately 120 cubic feet per second (cfs; 3.4 m 3 /sec) with a typical maximum
irrigation release of approximately 170 cfs (4.8 m 3 /sec).
Clear Lake has a winter carryover storage capacity of approximately 350,000 acre-feet,
corresponding to a maximum water surface elevation of 4,536.40 ft (1,382.70 m) between
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