Sources of springs supplying base flow to the Verde River headwaters, Yavapai County, Arizona

Multiple lines of evidence were used to identify
source aquifers, quantify their respective contributions,
and trace the ground-water flow paths that supply
base flow to the uppermost reach of the Verde
River in Yavapai County, Arizona. Ground-water discharge
via springs provides base flow for a 24-mile
long reach from the mouth of Granite Creek (river
mile 2.0) to Perkinsville (river mile 26). The flowing
reach is important to downstream water users, maintains
critical habitat for the recovery of native fish
species, and has been designated a Wild and Scenic
River. Sources of base flow are deduced from (a)
geologic information, (b) ground-water levels, (c)
precipitation and streamflow records, (d) downstream
changes in base-flow measurements, (e) hydrologic
analysis of water-budget components, and (f) stableisotope
geochemistry of ground water, surface water,
and springs. Combined, this information clearly indicates
that interconnected aquifers in Big Chino Valley
are the primary source of Big Chino Springs, presently
supplying at least 80 percent of the upper Verde
River?s base flow.