US Army Corps of Engineers
Northwestern Division

CRSO EIS Featured Project

COLUMBIA RIVER SYSTEM OPERATIONS EIS
Published May 16, 2019
McNary Dam, Lake Wallula, and associated facilities are operated for Hydropower, Navigation, Fish & Wildlife, Recreation, Water Quality, and Irrigation.

McNary Dam, Lake Wallula, and associated facilities are operated for Hydropower, Navigation, Fish & Wildlife, Recreation, Water Quality, and Irrigation. McNary Lock and Dam was authorized by Congress for power and navigation in the 1945 Rivers and Harbors Act. Construction began in 1947, and all turbine units were operational in 1957. Lake Wallula extends upstream of the dam for 64 miles to Hanford and has over 242 miles of shoreline.

Featured Project

The Columbia River System is large and complex. This educational feature introduces you to individual projects that play a role in supporting the region’s tribes, communities, industries and fish and wildlife species.

McNary Lock and Dam

The Corps of Engineers operates and maintains McNary Lock and Dam, located on the Columbia River in Umatilla, Ore. This dam is 7,365 feet long and provides for navigation, hydroelectric power generation, recreation, wildlife habitat and some irrigation. As a run-of-river dam, it does not provide water storage for flood risk management.
 
The navigation lock is the fourth of eight in the Columbia-Snake Inland Waterway, a 465-mile river highway that allows barge transport of commodities between the Pacific Ocean and Lewiston, Idaho. In 2015, more than five million tons of cargo passed through the 86-feet wide by 683-feet long lock.
 
McNary Dam’s 14 turbine units have a total generating capacity of 980 megawatts, enough to power about 686,000 homes. The Corps and the Bonneville Power Administration are collaborating to modernize the turbines to improve power and hydraulic capacity and incorporate the latest designs to improve turbine passage for fish. McNary is one facility in coordinated federal system of hydroelectric facilities that provides 35 percent of the entire power supply of the Pacific Northwest.  
 
McNary Dam was originally built with two 30-foot wide fish ladders–one on each shore–to provide a upstream passage route for migrating fish, including adult salmon and steelhead, lamprey and sturgeon.  In 2010 and 2014, the fish ladders were modified to better accommodate lamprey passage. The spillway, two spillway weirs and a juvenile bypass system (completed in 1994) provide downstream passage routes for juvenile fish.  The Corps annually spills for juvenile fish passage from April 10 through August 31.
 
Nearly 13,500 acres of public lands surrounding Lake Wallula behind the dam. This land, and much of the lake’s 242 miles of shore line, are used for recreation, wildlife habitat and water-connected industry. Currently, there are about 2,400 acres leased to state or local park agencies, 14 public boat launch facilities and eight commercial boat club facilities. The McNary National Wildlife Refuge is owned and managed by the U.S. Fish and Wildlife Service as part of the larger Mid-Columbia River Refuge Complex.
 
The Corps operates the McNary project in close coordination with the 13 other federal projects that comprise the Columbia River System and serve a wide range of purposes.