The Bureau of Reclamation’s May 2022 total water supply available forecast for the Yakima basin indicates the water supply will fully satisfy all senior users, while the junior water rights will receive an estimated 100% of their entitlements this irrigation season.
Precipitation was 112% of average from October through April and 161% of average in April. On May 1, the amount of water in the snowpack, known as snow water equivalent, was 115% of average in the upper Yakima and 101% in the Naches subbasins. Total Yakima Project reservoir storage on May 1 was 926,473 acre feet, 116% of average and 87% full.
Reclamation manages the water in the five Yakima Project storage reservoirs, along with the basin’s unregulated inflows to fulfill water rights, water contracts and instream flow obligations. Water shortages in the basin are shared equally by the junior water rights holders, which represent over half of the water rights in the basin.
Reclamation will provide an updated water supply forecast monthly—at least through July—using the latest data each month to reflect any changing conditions as they develop.
The May forecast is based on flows, precipitation, snowpack, and reservoir storage as of May 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 also are critical in determining stream flows, the extent to which the reservoirs fill, and the water supply for irrigation.
Original source can be found here.
