Infiltration into stratified alluvium : a comparison between simulated values and field measurements

Abstract

The computer model UNSAT2 for unsaturated water flow is used to complement a field study conducted at the University of Arizona Water Resources Research Center Field Laboratory during influent seepage along the Santa Cruz River during the runoff events on the Winter of 1967-1968. Field measurements accomplished by a neutron moisture logger showed that the hydrogeologic characteristics governing the movement and storage of subsurface flow are somewhat uniform throughout the area. The mathematical model provides a two-dimensional transient saturated-unsaturated analysis of the subsurface flow at the field site. The results attained using a conceptualized flow region proved to be an acceptable aid to a unified interpretation of the field measurements. Because boundary conditions are time and space dependent, the sensitivity to boundary conditions prevented the successful model calibration, although not its applicability. This, together with more serious limitations on data availability and computer capacity, precluded the imminent use of the computer model UNSAT2 for this individual research site.