McKay Dam


McKay Dam is located on McKay Creek about 6 miles south of Pendleton, Oregon. It was constructed to furnish a supplementary supply of water to Stanfield and Westland Irrigation Districts. The dam is an earthfill structure with a reinforced concrete paved upstream slope. It is 165 feet high and contains 2,364,000 cubic yards of material. At closure in 1927, the reservoir had a total storage capacity of 73,800 acre-feet (active 73,800 acre-feet). In 1993, a sedimentation survey estimated the total reservoir storage capacity at 71,500 acre-feet (active conservation is 65,534 acre-feet).

McKay Dam was originally constructed during 1923-1927. Modification of the spillway section was made in 1978-1979 to increase the capacity from 10,000 to 26,910 cubic feet per second. In 1991, the needle valves were replaced with the new jet flow gates. Safety of Dams work on the left abutment included the excavation and replacement of low-strength foundation materials, construction of two 700-foot berms on the upstream and downstream sides, and the installation of a drainage system.

RegionFacilities in Pacific Northwest | Pacific Northwest Home Page
CountyUmatilla, Morrow
ProjectUmatilla Basin
Dam TypeEarthfill with u/s concrete facing
WatercourseMcKay Creek
Location6 mi S of Pendleton
Original Construction1923-1927
Modified Construction
National ID NumberOR00583
Hydrologic Unit Code

Structural Height165.0 ft
Hydraulic Height (Normal Operating Depth at Dam)158.0 ft
Top Parapet (Elevation)
Spillway Crest Elevation1329.3 ft
Crest Elevation1330.0 ft
Crest Length2700.0 ft
Crest Width
Base Width
Volume of Dam Construction Materials
Streambed at Dam Axis
Top of Exclusive Flood Control Pool (Elevation)
Top of Joint Use Pool (Elevation)
Top of Active Conservation Pool (Elevation)1317.1 ft
Top of Inactive Conservation Pool (Elevation)
Top of Dead Storage Pool (Elevation)

Hydraulics & Hydrology
Total Water Storage at Elevation 65,534 ac-ft plus 6,000 ac-ft flood space to elev. 1322 ft
Maximum Water Surface Elevation
Normal Water Surface Elevation1317.1 ft
Spillway Type Gated
Auxiliary SpillwayNo
Spillway Capacity at Elevation26,910 cfs at 1329.3 ft
Auxiliary Spillway Capacity at Elevation
Uncontrolled Spillway Capacity at Elevation
Outlet Works Capacity at Elevation1,240 cfs
Diversion Capacity at Elevation
Drainage Area186.00 sq mi
Hydrometeorological Report (HMR)HMR
Probable Maximum Flood (PMF) Report

Contact Information
TitleArea Office Manager
OrganizationColumbia-Cascades Area Office
Address1917 Marsh Road
CityYakima, WA 98901-2058
Phone (Fax)509 454-5611
Phone (Office)509 575-5848 x202
TitleArea Office Manager
OrganizationUmatilla Field Office
Address32871 Diagonal Road
CityHermiston, OR 97838
Phone (Fax)509 454-5611
Phone (Office)541 564-8616

Last updated: May 04, 2012