New Mexico Geological Society Annual Spring Meeting — Abstracts

The soils on the La Mesa and Las Canas surfaces (New Mexico) are underlain by an indurated calcic horizon which is considered impermeable for soil water. However, an important feature of this horizon is the presence of pipes which are filled with permeable soil materials and, thus, may act as water conduits during periods with precipitation. During the installation of a gas pipeline on the La Mesa Surface in October 1998 we have inspected more than 280 pipes along a 32 km long trench with a depth of 2.2 m. Average pipe density varies from about one pipe in every 14 to 38 m² pipe distance from 22 to 58 m, and average pipe diameter from 4.2 to 8.5 m. Approximately15 to 19 percent of the total land surface is occupied by pipes. Generally, wetting fronts inside the pipes were deeper than in adjacent areas. Our study suggest that pipes in indurated calcic horizons cause considerable focused recharged in arid New Mexico.