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Pacific Northwest Region
Boise, Idaho
Media Contact:
Kate Puckett
509-575-5848 x205

Released On: June 09, 2003

Reclamation Announces June Water Supply Forecast for Yakima Basin
The June 2003 forecast of the Yakima Basin water supply, based on snowpack and precipitation data available on the first of June, indicates a full water supply for all users for the 2003 irrigation season.

Converting the June 1st runoff forecast (natural flow) to total water supply available (TWSA) gives the following volumes for the June through September use period:

With 50% normal subsequent conditions 1.92 million acre-ft With 100% normal subsequent conditions 2.00 million acre-ft (most likely) With 150% normal subsequent conditions 2.09 million acre-ft.

Total demand to be placed against this supply for irrigation, regulation, and flows passing Sunnyside Dam averages 2.5 million acre-feet in a normal year.

The Title XII target flow at the Yakima River near Parker gaging station is 400 cfs based on the June 1 forecast. Total demand to be placed against this supply for irrigation, regulation, and flows passing Sunnyside Dam averages 2.5 million acre-feet in a normal year.

This is a below average year for water supply. Subsequent precipitation is only one factor affecting the amount of water supply available. Diversion rates and the timing of the run-off are critical in determining the storage control date and the available water for irrigation. Storage control is expected to begin sometime in mid-June. Once the Project is on storage control, system reservoir volume will decline as water is released to meet demands.

Storage conditions as of June 1 were as follows:

Reservoir Content (acre-feet) Total Capacity Percent of Capacity Keechelus 86,563 157,8001 58 Kachess 228,170 239,000 95 Cle Elum 420,230 436,900 96 Bumping 34,373 33,700 102 Rimrock 198,100 198,000 100 Totals 967,436 1,065,400 91

1Keechelus capacity is currently restricted to 140,300 acre-feet. Normal capacity is 157,800 acre-feet.

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