Biological Opinions - Bureau of Reclamation

Figure 11.3. Historic April through November deliveries to Project from Upper Klamath Lake.
11.3.8.2 Agriculture
Crop cultivation and livestock grazing in the upper Klamath Basin began in the mid-1850s.
Since then, valleys have been cleared of brush and trees to provide more farm land. By the late
1800s, some native perennial grasses were replaced by non-native species. This, combined with
soil compaction, resulted in higher surface erosion and greater peak water flows in streams.
Other annual and perennial crops cultivated included grains, alfalfa hay, potatoes and corn.
Besides irrigation associated with Reclamation’s Klamath Project, other non-Project irrigators
operate within the Klamath River Basin. Irrigated agriculture both above (e.g., Williamson,
Sprague, and Wood rivers) and surrounding UKL consists of approximately 180,000 acres.
Excluding Reclamation’s Project, estimated average consumptive use in the upper Klamath
Basin is approximately 350,000 acre feet per year (NRC 2004). Irrigated agricultural land in the
Shasta River and Scott River valleys consist of approximately 51,600 acres and 33,000 acres,
respectively (Reclamation 2009). Estimated consumptive use of irrigation water by crops in the
Shasta and Scott River valleys is approximately 100,000 and 71,000 acre-feet per year,
respectively.
Actual diversions would exceed the consumptive use of the crops due to irrigation application
methods, conveyance losses in the system and surface evaporation. Current agricultural
development in the Scott River Valley, which has increased significantly since the 1970s,
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