The Bureau of Reclamation's Yakima Basin Total Water Supply Available (TWSA) forecast for July indicates a full water supply for both senior and junior water rights, according to Chuck Garner, Yakima Project River Operations supervisor.
Garner said water managers and fisheries can expect above normal runoff this season thanks to above average snowpack and reservoir storage. The reservoirs are essentially full and the natural runoff is expected to provide for demands into early or mid-July. This will save on stored water and leave the reservoirs with above average carry over for next year.
Both junior and senior water rights holders are expected to receive their full water supply. The water supply forecast has been updated each month through July. Specific water delivery levels will be determined later in the year when storage begins to decline, likely in early to mid-July.
The July TWSA forecast is based on flows, precipitation, snowpack and reservoir storage as of July 1, along with estimates of future precipitation and river flows. Other future weather conditions that determine the timing of the runoff and the demand for water are also critical in determining stream flows, distribution of water and reservoir storage.
Garner said that the remaining snowmelt, the summer weather and the irrigation demands are still important and can influence the carry over storage at the end of the season. He advises all Yakima basin water users to use their water prudently even in this above average runoff year.