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O'Sullivan Dam

O'Sullivan Dam, Washington (Click to Enlarge)


Statistics

General

  • Region (Map) : ................. Pacific Northwest
  • State (Map) ...................... Washington
  • County .............................. Grant
  • Project: .............................. Columbia Basin
  • Dam type: ......................... Earthfill
  • Location: .......................... 22 mi S of Ephrata
  • Watercourse: ................... Lower Crab Creek
  • Reservoir: ......................... Potholes
  • Construction Date: ..........1947-1949
  • National ID Number ........ WA00268
  • Hydrologic Unit Code ....

Dimensions


Hydraulics

  • Normal Water Surface Elev: ................1052.0 ft
  • Hydraulic Height: .................................. 153.0 ft
  • Service Spillway Type:
  •    Uncontrolled  Crest    ................................ No
  •    Morning-Glory ........................................... No
  •    Crest Length    .....................................24 ft x 4
  •    Gated      ..................................................... Yes
  •    Capacity at Elev:  1048.0  ft,           29,600 cfs
  • Auxiliary Spillway ........................................ No
  •     Capacity at Elev.   ................................. 0 cfs
  • Outlet Works Capacity at
  •     Elevation  1052.0 ft.,  ...................... 1,200 cfs

Hydrology

  • Drainage Area: ................................ 3,920.0sq mi
  • Hydrometeorological Report (HMR):   HMR 57
  • Flood Type: ................................ Winter General
  • Storm Duration: .......................................... 72 hrs
  • Probable Maximum Flood (PMF) Report:
  •   Peak Inflow: ....................................... 52,100 cfs
  •   Inflow Volume: .......................... 395,000 acre-ft
  •   Flow Duration: .......................................15 days
  •   PMF Routing MWS Elev.: .......................... NA
  •   Initial Routing Elev: ............................. 1061.0 ft
  •   Study Date: .................................. October 1993


Power Generation


Narration

 


Geology

Bedrock in the area of O'Sullivan Dam consists principally of basalt flows and interflow zones of the same general type as encountered elsewhere in the Columbia basin project.  Exposures of Ringold formation sediments occur in Lind Coulee to the east of the dam site area, but not within the actual foundation area of the dam.  Overburden within the damsite area consists of a thin, discontinuous cover of windblown silt and sand which, together with sand and gravel, partially fills many of the potholes and channels cut into the basalt flows.  Several of the channels in the southwesterly portion of the area contain deposits of sodium sulfate derived from the evaporation of the seasonal lakes.  A predominant terrace of sand and gravel overlies the basalt and Ringold sediments to the north.  Toward the northwest the surface of the reservoir area is covered by superficial deposits of sand gravel and windblown sand.  Beneath these overburden materials are the Ringold sediments and the basalt flows.  The basalt flows of the dam site area range from near horizontal to gently warped except for a narrow zone of disturbance known as the Lind Coulee Flexure.  This zone was characterized by faulting and sharp folding, trends in a rather irregular fashion in a general east-west direction through the dam site area.

Links

 | Recreation |

 | Dams Located by State | USBR Washington Dams | Pacific Northwest Region Dams |

 | Owner: Upper Columbia Area Office, PO Box 1749, Yakima, WA 98907-1749,
  (509) 575-5848 ext 202

Operator: Upper Columbia Area Office, PO Box 1749, Yakima, WA 98907-1749,
  (509) 575-5848 ext 202



 

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