The water year that ended Saturday was the wettest on record for the watersheds feeding the Tuolumne and Stanislaus rivers. The Merced River fell just short. The Tuolumne had about 4.86 million acre-feet of runoff from rain and snowmelt from last October through September, the Turlock Irrigation District reported. That beat the previous high of 4.64 million in 1983 and was 255 percent of the historical average, spokesman Brandon McMillan said.