Snowpack-Runoff Relationships for Forested Mid-Elevation Watersheds and a High-Elevation Watershed in Arizona

Snowmelt from higher elevation forested watersheds is a major source of runoff for most of the rivers in the southwestern United States. Snowpacks in the Southwest melt intermittently throughout the winter. At some mid-elevation locations, between 2,135 and 2,285 m (7,000 and 7,500 ft), snowpacks appear and disappear, depending on the distribution of storms and temperature fluctuations during the winter. Snowpacks at higher elevations may experience periods of melting but generally accumulate snow throughout the winter with most snowmelt occurring during the spring. The USDA Natural Resources Conservation Service (NRCS) maintains a system of measuring stations to index snow conditions and predict snowmelt runoff. Peak snow water equivalent data from NRCS stations have been related to snowmelt runoff volumes and mean daily peak flows for the three mid-elevation Workman Creek watersheds north of Globe, Arizona and for the high-elevation East Fork of Willow Creek in the White Mountains of eastern Arizona. The statistically significant relationships for Workman Creek are being used as a basis to measure the effects of the Coon Creek Wildfire on watershed hydrology and to estimate winter streamflows for the years when the installations were closed. The comparisons between mid and high-elevation watersheds will increase our knowledge of snowmelt dynamics in the Southwest.