Water Resources Division

Flood Control


Levees are earth structures that keep elevated waters from flooding interior lowlands. Yakima County has 21.8 miles of levees. 15.1 Levee miles are certified by the Army Corps of Engineers for different flood level events, and are maintained per Corps requirements, while the rest are orphan levees that have no certification.

Flood Plains Levees
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8.6 Miles Authorized Federal Levees

6.5 Miles PL84-99 Certified Levees

6.7 Miles Non-Certified "Orphan" Levees

City of Yakima and Terrace Heights Protected to 100 Year Flood Event

Lateral Confinement of Levees Increasing Maintenance

Yakima 1927
Yakima 2004
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1927 Overlay2004 Infrastructure Overlay on 1927 Photo

Energy and Sediment Dispersal °Disrupted river processes
°Lateral constraint
°River attack at constraints
°Reduced area for sediment deposition


Certified Levees Constructed by the
Federal Government.
Operation and Maintenance Manual
Lower Naches River
Upper Naches River 
Non-Federal Levees Systems in
the Federal Program

Levee Owner’s Manual for Non-Federal Flood Control Works

The Levee Owner’s Manual for PL84-99 was written specifically for the public sponsors of non-Federally constructed levees, floodwalls, channels, and other Flood Control Works. It describes the proper operation and maintenance of these structures, and the assistance the U.S. Army Corps of Engineers can provide before, during, and after a flood.