Conceptual hydrologic systems for Sante Fe County
— Amy C. Lewis and Francis West

Santa Fe County is divided into three major aquifer or hydrologic systems: the north Santa Fe County aquifer system, the mid-Santa Fe County hydrologic system, and the Estancia Valley aquifer system. The primary aquifer in the north Santa Fe County aquifer system is composed of Santa Fe Group sediments and is bounded to the east by Precambrian crystalline rocks and to the west by Tertiary basalts. Water quality is generally very good, although very hard. The saturated thickness probably exceeds 3500 ft and the aquifer contains sufficient water to supply existing demands for many hundreds of years if legal and administrative issues are ignored. The mid-Santa Fe County hydrologic system consists of sedimentary rocks from Permian to Tertiary age. The hydrogeology of this system is poorly understood, but water quality is generally poor throughout. The primary aquifer in the Estancia Valley aquifer system in southern Santa Fe County is composed of valley fill deposited in a structural trough, with thicknesses up to 350 ft. The formations that either underlie or crop out along the margins of the basin include Pennsylvanian to Triassic sedimentary rocks. Water quality deteriorates toward the center of the basin (from 300 to almost 3000 ppm TDS), but is suitable for irrigation even in the worst areas. The quantity in storage is estimated to be over 1,000,000 ac-ft and is sufficient to supply existing demands for at least 80 yrs.