Wahluke Slope is a geographic feature in Grant, Benton and Adams Counties of Eastern Washington. It is a broad, south-facing slope with a grade of about 8%, situated between the Saddle Mountains and the Columbia River's Hanford Reach. It has been described as "basically a 13-mile-wide gravel bar" created by the Glacial Lake Missoula floods at the end of the last ice age about 15,000 years ago. Much of the Slope, part of the Hanford Nuclear Reservation, was added to the Saddle Mountain National Wildlife Refuge in 1999. Much of the remainder is used for viniculture.
Washington State Route 24 extends from Mattawa, Washington on the western edge of the Slope nearly due east-west. Mattawa is the only population center on the Slope. There was once a town of Wahluke and a Wahluke ferry that crossed the Columbia to the north of White Bluffs. The land was acquired by the U.S. government for the Hanford Nuclear Reservation and the residents, including Wanapum people, ordered to leave in 1943. In two actions in 1953 and 1958 the Atomic Energy Commission returned almost 200,000 acres (810 km2) to public use, mostly for agriculture with irrigation recently provided by Columbia Basin Project sources. Settlement on the Slope by non-Native Americans has been termed as troubled, initially due to lack of water, then later by the Federal Government's land policies, resulting in "sporadic" growth of the town of Mattawa.
The potential for release of nuclear contaminants into the Slope in the event of a nuclear accident, and the historical atmospheric releases in the ranges of many Curies per month, are of concern to modern authors on Hanford.
Viniculture is a major agricultural activity on the Slope, with nearly 10,000 acres (40 km2) of vinyards.
- Wahluke Slope characteristics, Washington State Wine Commission
- "Wahluke Slope is one of Washington wine country's hidden gems", Northwest wine blog, Seattle Post-Intelligencer, July 28, 2010
- Ken Olsen (December 20, 1999), "Hanford leaves a surprising Cold War legacy", High Country News
- Saddle Mountain Unit (PDF) (Fact sheet), U.S. Fish and Wildlife Service, August 2002
- Metsker's Map of Grant County, Washington – via King County Library System collection
- Sanger 1995, pp. 16–18.
- Brown 2013, p. 187.
- Kirk & Alexander 1995, p. 116.
- Brown 2013.
- Gerber 2007.
- PSR 2010.
- Brown, K. (2013), "Wahluke Slope: Into Harm's Way", Plutopia: Nuclear Families, Atomic Cities, and the Great Soviet and American Plutonium Disasters, Oxford University Press, pp. 185–188, ISBN 978-0-19-985576-6
- Daniel (September 21, 2010), "Radioactive emissions to the Wahluke Slope", Toxipedia (Washington Nuclear Museum and Educational Center), Physicians for Social Responsibility Washington chapter
- Gerber, M.S.; Findlay, J.M. (2007), "Airborne wastes and the Columbia Basin Irrigation Project", On the Home Front: The Cold War Legacy of the Hanford Nuclear Site, University of Nebraska Press, pp. 107–112, ISBN 978-0-8032-5995-9
- Kirk, Ruth; Alexander, Carmela (1995), Exploring Washington's Past: A Road Guide to History, University of Washington Press, ISBN 9780295974439
- Sanger, S.L. (1995), Wollner, Craig, ed., Working on the Bomb: An Oral History of WWII Hanford, Portland State University Continuing Education Press, ISBN 0-87678-115-6
- U.S. Geological Survey Geographic Names Information System: Wahluke Slope
- Wahluke Slope map and discussion at Wines Northwest