Name of Dam

State

Project

Region

Dam Use

O´Neill Forebay

California

CVP - San Luis

Mid Pacific

Rereg

O´Sullivan

Washington

Columbia Basin

Pacific Northwest

Storage

Oak Street

Oregon

Rogue River Basin

Pacific Northwest

Diversion

Ochoco

Oregon

Crooked River

Pacific Northwest

Storage

Ogden Valley

Utah

Weber Basin

Upper Colorado

Diversion

Olympus

Colorado

Colorado-Big Thompson

Great Plains

Storage

Ortega

California

Cachuma

Mid Pacific

Storage

Oso

Colorado

San Juan-Chama

Upper Colorado

Diversion

Owyhee

Oregon

Owyhee

Pacific Northwest

Storage