The Tonto watershed (HUC 15060105) covers approximately 1,721 square miles in central Arizona. The hydrology of the watershed is dominated by the Salt River, which flows through the area and supplies water for Phoenix and other municipalities. Snowpack in the watershed is limited, with only a small percentage of the precipitation falling as snow. Surface water in the watershed is primarily found in the Salt River and its tributaries, which are used for water supply and recreation. Reservoirs in the watershed include Roosevelt, Apache, and Canyon Lakes. Interesting climatic facts include the monsoon season from late June to September, which can bring heavy rain and flash flooding to the area. There has been a trend towards increasing temperatures and decreasing precipitation in the region, which could have significant impacts on water resources in the future.