GEOTHERMAL STUDIES OF GROUND-WATER FLOW CHARACTERISTICS, ALBUQUERQUE BASIN

High precision temperature logs have been made at thirty piezometer nests in the Albuquerque Basin, twenty-seven of these logs are at sites in and near to the Albuquerque metropolitan area. From these data several fundamental characteristics concerning the ground-water flow pattern in the area are suggested. At sites in the inner valley and/or near the Rio Grande there is a shallow flow zone, from near the water table to depths=150 m, with a cooling horizontal specific discharge, derived from the river, typically tens to more than a hundred m/yr. A similar shallow cooling flow component is present in the northeastern and east-central part of the study area as well, and also in the western part of the Albuquerque Basin near the floodplain (although the flow is typically a good deal less in magnitude than in the floodplain). The cooling component of shallow ground-water flow in the areas outside the inner valley is also believed to come ultimately from the river. Temperature data indicate a deeper flow zone occurs at many sites along the inner valley and in the bordering eastern and western highlands. Data indicate that the deeper flow can have a warming horizontal flow component less in magnitude than the shallower flow, and at some sites the warm flow comes from higher elevations where the water table is deeper and warmer. It appears that faults act as both conduits for downward ground-water flow or as seals restricting flows. Small specific discharge estimates indicating warm flow at some sites in the west mesa are consistent with the location of faults that are sealed, restricting flow from the Rio Grande. Hydraulic conductivity estimates show a statistical difference in the mean horizontal values between sites in the east and west mesas, consistent with faults acting to slow flow west of the Rio Grande and the past deposition of Rio Grande sediments in the eastern part of the Albuquerque Basin. Regional recharge to the Rio Grande from the bordering eastern highlands is probably small, taking hundreds to thousands of years to move from the Sandia Mountains to the Rio Grande.