| John Day Dam | |
| Dam Crosses: | Columbia River |
| Location: | Sherman County, Oregon / Klickitat County, Washington United States |
| Dam Type: | Concrete gravity, run-of-the-river |
| Dam Length: | 23270NaN0 |
| Dam Height: | 560NaN0 |
| Spillway Type: | Service, gate-controlled |
| Construction Began: | 1958 |
| Opening: | 1971 |
| Cost: | US$511 million |
| Res Name: | Lake Umatilla |
| Res Capacity Total: | 2530000acre feet |
| Plant Operator: | U.S. Army Corps of Engineers |
| Plant Turbines: | 16 × 140 MW |
| Plant Capacity: | 2,240 MW |
| Plant Annual Gen: | 8,418 GWh (2009)[1] |
| Plant Type: | R |
| Coordinates: | 45.7164°N -120.6944°W |
The John Day Dam is a concrete gravity run-of-the-river dam spanning the Columbia River in the northwestern United States.[2] The dam features a navigation lock plus fish ladders on both sides. The John Day Lock has the highest lift (at 110sp=usNaNsp=us) of any U.S. lock.[3] The reservoir impounded by the dam is Lake Umatilla, and it runs 76.4miles up the river channel to the foot of the McNary Dam. John Day Dam is part of the Columbia River Basin system of dams.
John Day Dam is located 28miles east of the city of The Dalles, Oregon, and just below the mouth of the John Day River. The closest town on the Washington side is Goldendale, 20miles north. The closest town on the Oregon side is Rufus, Oregon. Its crest elevation is approximately 570feet above sea level. It joins Sherman County, Oregon with Klickitat County, Washington, 216miles upriver from the mouth of the Columbia near Astoria, Oregon.
Construction of the dam began in 1958 and was completed in 1971,[4] making it the newest dam on the lower Columbia, at a total cost of US$511 million. The pool was filled in 1968 and a dedication ceremony was held on September 28, 1968.[5] John Day Dam was built and is operated by the U.S. Army Corps of Engineers. The condemnation of land upstream of the dam led to the Supreme Court case United States v. Rands,[6] a well-known case regarding the constitutional doctrine of navigable servitude. The dam's power generation capacity is 2,480,000 kW (overload capacity). The dam underwent a major repair to the upper lock gate in 2010, as documented in an episode of the National Geographic Channel program World's Toughest Fixes.[7]
As of 2007, the 76-mile-long reservoir formed the deadliest stretch of the Columbia River for migrating young salmon.[8]