The Yakima River is the largest tributary of the Columbia
wholly in Washington (The Snake is a larger river, but it only passes through
southeastern Washington to its confluence with the Columbia). The Yakima River
basin comprises 6,100 square miles in the south-central portion of the state.
The basin is bordered on the west by the Cascade Mountains, on the north by the
Wenatchee Mountains, on the east by the Columbia, and on the south by the
Simcoe Mountains and the Horse Heaven Hills.
The Yakima basin supports at least
48 species of anadromous, resident native, and introduced species of fish, as
well as more than 250 species of wildlife. Historically, the Yakima was one of
the major producers of salmon and steelhead in the Columbia River Basin. It is
estimated that before large-scale Euro-American emigration and settlement began
around 1850, some 500,000 to 900,000 adult salmon and steelhead returned from
the ocean to spawn in the Yakima basin annually. These included spring, summer
and fall Chinook, coho, sockeye, and steelhead. Today, summer Chinook, sockeye,
and native coho are extinct in the basin (hatchery-bred coho have been
introduced). The number of returning adult fish is far below the historic
number. In the late 1990s and early 2000s, spring Chinook returns varied from
645 fish to more than 25,000. Fall Chinook returns averaged 2,000 to 4,000
fish, and coho returns were between 1,000 and 2,000 fish. The Yakima Nation is
working to rebuild the salmon and steelhead runs through a large-scale
hatchery program that produces juvenile fish for release into the
wild in an experiment to rebuild naturally spawning runs. Two fish species in
the Yakima basin are listed for protection under the Endangered Species Act,
bull trout and mid-Columbia steelhead.
The population of the Yakima basin
was 293,790 in 2000, an increase of nearly 30,000 in 10 years. The largest city
is Yakima. By 2020, the population of the basin is expected to be about
425,000. The biggest land owner in the basin is the U.S. government with 1.5
million acres, most of it in national forest and a military training range. The
second-biggest land owner is the Yakima Nation, whose reservation covers 1.4
million acres in the southern part of the basin. The entire Yakima basin lies
within areas either ceded to the U.S. government by the Yakama tribes in the
Treaty of 1855 or reserved by the tribes in the treaty.
Nearly 40 percent of the Yakima
basin is forested, and another 40 percent is rangeland. Fifteen percent of the
basin is cropland. Predominant land uses include grazing (2,900 square miles),
timber harvest (2,200 square miles), irrigated agriculture (1,000 square
miles), and cities and towns (50 square miles). The climate in most of the
basin is dry, with rainfall averaging 10 inches per year with the exception of
the highest parts of the mountains on the western edge of the basin. According
to a 2004 report on the basin, important crops include apples, hops, grapes,
cherries, mint, forage crops, dairy products, and beef cattle, and the basin is
one of the nation’s top producers of apples, hops, cherries, and mint.
The Bureau of Reclamation owns and
operates six reservoirs for irrigation as part of the Yakima Reclamation
Project. The total storage capacity is 1.07 million acre-feet. There are three
small federal hydroelectric dams in the basin, but otherwise hydropower
production is not a major use of water in the basin.