Maximum discharge along the river was observed at the Yakima River At Mabton with a streamflow rate of 2,640 cfs. However, the deepest point on the river is located at the Yakima River Above Ahtanum Creek At Union Gap reporting a gauge stage of 40.62 ft. This river is monitored from 4 different streamgauging stations along the Yakima River, the highest being perched at an elevation of 1,338 ft, the Yakima River At Umtanum.