Lake Umatilla

Lake Umatilla
Name	Lake Umatilla
Location	United States; Oregon–Washington
Type	Reservoir
Inflow	Columbia River
Outflow	Columbia River
Basin countries	United States
Length	35 km
Area	12,000 ha
Created	1950s

Lake Umatilla is a reservoir on the Columbia River formed by the construction of a major hydroelectric project in the mid-20th century. It occupies a reach of river between John Day Dam and surrounding topography, integrating riparian corridors, island systems, and managed wetlands important to regional transportation and resource industries. The impoundment influences riverine dynamics that interconnect with major Pacific Northwest infrastructure, basin planning, and treaty-era resource allocations.

Geography

Lake Umatilla lies along the border region of Oregon and Washington within the greater Columbia Plateau and the Columbia River Gorge physiographic settings. The reservoir inundates parts of counties such as Umatilla County, Oregon, Morrow County, Oregon, and Benton County, Washington and is proximate to municipalities including Hermiston, Oregon, Boardman, Oregon, and Kennewick, Washington. Topographically it occupies a valley segment between basaltic escarpments formed during the Missoula Floods episodes and integrates terraces associated with the Yakima Fold Belt and historic Columbia River Basalt Group flows. Several islands and sloughs within the impoundment connect to infrastructure corridors like Interstate 84 and U.S. Route 730, and to rail lines operated historically by Union Pacific Railroad and BNSF Railway.

Hydrology and Water Management

The reservoir’s hydrology is governed primarily by regulation at John Day Dam and coordinated within the Columbia River system alongside projects such as Bonneville Dam, The Dalles Dam, and McNary Dam. Flow control supports hydroelectric generation by entities including the United States Army Corps of Engineers and aligns with allocations under the Columbia River Treaty frameworks and actions by the Bonneville Power Administration. Seasonal storage and release patterns respond to snowmelt in the Cascade Range, inflow variations from tributaries like the Umatilla River and Walla Walla River, and agreements involving the Bureau of Reclamation and state water management agencies such as the Oregon Water Resources Department and the Washington Department of Ecology. Navigation locks, dredging operations, and levee maintenance are coordinated with port authorities including the Port of Umatilla and the Port of Morrow.

Ecology and Wildlife

The impoundment created a mosaic of aquatic and wetland habitats that support species managed by agencies such as the U.S. Fish and Wildlife Service, Oregon Department of Fish and Wildlife, and Washington Department of Fish and Wildlife. Populations of anadromous fish like Chinook salmon, steelhead trout, Coho salmon, and sockeye salmon interact with freshwater species including smallmouth bass, walleye, and sturgeon in managed fisheries. Riparian zones and adjacent wetlands provide stopover and breeding habitat for migratory birds on the Pacific Flyway including American white pelican, great blue heron, and various Anas species; these areas are also important for conservation units such as McNary National Wildlife Refuge and local preserves like Boardman State Park. Aquatic plant communities and benthic invertebrates reflect influences from nutrient inputs, invasive species dynamics studied by researchers at institutions like Oregon State University and Washington State University.

History and Human Use

The riverine reach occupied by the reservoir has long been part of the traditional territories of Indigenous nations such as the Umatilla Tribe, Nez Perce Tribe, and Confederated Tribes of the Warm Springs Reservation of Oregon. Euro-American exploration and commercial activity increased with expeditions like the Lewis and Clark Expedition and later steamboat navigation, followed by railroad expansion by corporations such as the Oregon Steam Navigation Company and later Northern Pacific Railway. The mid-20th-century dam program that created the impoundment involved federal projects enacted by the Congress of the United States and construction practices overseen by the Army Corps of Engineers, reshaping land use for agriculture, irrigation projects implemented by the U.S. Bureau of Reclamation, and industrial logistics linked to ports and railheads. Land claims, treaty rights, and litigation involving entities such as the U.S. Supreme Court and tribal governments have shaped access to fisheries and resources.

Recreation and Tourism

Lake Umatilla supports recreational activities promoted by state parks and local tourism bureaus including Oregon State Parks and county visitor associations. Popular uses include boating, sport fishing targeting species managed under rules from the Pacific States Marine Fisheries Commission, birdwatching tied to the National Audubon Society lists, and camping at sites managed by agencies including U.S. Army Corps of Engineers recreation units. Nearby attractions and amenities link visitors to cultural sites such as the Tamástslikt Cultural Institute, outdoor venues like McNary National Wildlife Refuge, and regional events promoted by chambers of commerce in Hermiston, Boardman, and Pendleton, Oregon.

Environmental Issues and Conservation

Environmental concerns center on fish passage challenges for salmon and steelhead, habitat loss from inundation, water quality issues related to nutrient loading and algal blooms, and invasive species including zebra mussel and nonnative aquatic plants documented by research programs at Environmental Protection Agency regional offices. Conservation responses involve restoration partnerships among the U.S. Fish and Wildlife Service, tribal co-managers such as the Confederated Tribes of the Umatilla Indian Reservation, nongovernmental organizations like The Nature Conservancy, and academic collaborators at University of Oregon and Portland State University. Adaptive management strategies incorporate measures from the Columbia Basin Fish Accords, habitat enhancement projects funded under federal programs, and cross-jurisdictional planning coordinated with state and regional bodies to mitigate impacts while balancing power generation, navigation, agriculture, and cultural resource protection.

Category:Reservoirs in the Columbia River basin