The Hat Watershed (HUC 10120108) covers an area of 1,404 square kilometers in southeastern Alberta and southwestern Saskatchewan, Canada. It is a predominantly flat area with a mixed-grass prairie ecosystem. The watershed is part of the South Saskatchewan River Basin and is drained by the Red Deer River, which flows into the Bow River and ultimately into the South Saskatchewan River. The Hat Watershed experiences a semi-arid climate with hot summers and cold winters. Snowpack accumulation is generally low due to its arid nature. The watershed is home to several natural and artificial reservoirs, including Reesor Lake, and several irrigation canals. The main economic activities in the area are agriculture and oil and gas production. The watershed is also home to a diverse range of wildlife, including pronghorn antelope, mule deer, and coyotes. The area has seen a trend towards drier conditions over the past few decades, with increased frequency and severity of droughts.