The Bill Williams Watershed covers an area of approximately 1,240 square miles in western Arizona, primarily in Mohave and Yavapai counties. It includes the Bill Williams River and numerous tributaries, which feed into Alamo Lake Reservoir. The watershed is characterized by hot, arid conditions with a low annual precipitation of around 10 inches. Snowpack is rare, and the area relies heavily on monsoonal rains for surface water recharge. The Bill Williams River is a vital source of water for agriculture, mining, and recreation. The Alamo Lake Reservoir is primarily used for irrigation and flood control. Interesting climatic trends in the region include a warming trend over the past few decades, resulting in earlier snowmelt and a shift toward more rainfall than snowfall. The watershed is also susceptible to flash flooding during monsoon season.