Analysis of vertical hydraulic conductivity using heat as a tracer to estimate streambed infiltration In Rillito Creek, Tucson, Arizona

Abstract

Heat as a tracer was used to estimate one-dimensional vertical infiltration at three study sites in Rillito Creek in Tucson, Arizona, by inversely determining the vertical saturated hydraulic conductivity profiles beneath the streambed. The study sites are referred to as Craycroft Road, Dodge Boulevard, and First Avenue, and are located in Rillito Creek 19.46, 15.63, and 10.27 kilometers, respectively, upstream from the confluence of Rillito Creek and the Santa Cruz River. Results from the uppermost site indicated that a significant physical change had occurred at the streambed between the first and second model periods that lowered the hydraulic conductivity and the infiltration rate by up to four orders of magnitude. A similar change in conductivity is suggested by the simulation results from the two lower sites; however, these results indicated that changes in hydraulic conductivity and the infiltration rates occurred during a single flow event.