Vadose zone fluid flow estimates calculated from temperature measurements taken in the southern Albuquerque Basin at Tome, New Mexico

Closely spaced temperature measurements taken across the vadose zone at Tome, New Mexico, suggest upward and/or horizontal fluid flow between ~58 and ~30 m depth. The temperature-depth profile is an independent data set that in the present example is best fitted by the exponential expression characterizing vertically upward water flow. In addition, expressions representing horizontal flow and combined horizontal and vertical flow also provide relatively good fits to the temperature data. A unique hydrogeologic environment is present at the Tome site, where a thick clay layer straddles the water table at ~59 m depth. Neutron and bulk density porosity logs indicate the clay porosity is largely liquid phase water filled. It is suggested that matrix potential and perhaps osmosis are able to drive an uncommonly large vertical fluid flow for southwestern U.S. desert vadose zone sites because the presence of the saturated clay layer straddling the relatively shallow water table provides ideal conditions. The vertical specific discharge estimate is ~0.09 m yr^-1 liquid water. Horizontal flow may also be possible in the clay layer and is estimated as ~23 m yr-1. Both the vertical and horizontal flow estimates are not untypical for the saturated zone in the Albuquerque Basin.