Big Sand Wash Reservoir is located north of Upalco in Duchesne County. DEQ’s recreational water quality monitoring checks for two health concerns: Harmful Algal Blooms (HABs) and Waterborne Pathogens (E. coli). Find the most recent Big Sand Wash monitoring information below. Updates: November 1, 2024: Harmful algal bloom (HAB) and E. coli monitoring update Recreational…