干旱区生态环境知识资源中心

Defining the hydrologic setting of the Waste Isolation Pilot Plant (WIPP) is an important step for site characterization and performance assessment. From past research there is a controversy about the timing of recharge to the aquifers in the Rustler Formation which overlies the repository. The stable isotopic composition (delta D and delta(18)O) of the water has been used in this argument but with ambiguous conclusions. Soil cores from WIPP have been sampled for delta D, delta(18)O, Cl- and water content. The data indicate the there is a small amount of infiltration (.2 to 2 mm/yr) through the desert soil. The delta D and delta(18)O analyses suggest that meteoric water in the area can have a stable isotope composition similar to that in the Rustler Fm. Further supporting evidence come from the isotopic composition of drip and pool waters in nearby Carlsbad Caverns. This indicates that the water in the Rustler Fm. need not have been recharged in the past (> 10,000 yrs.) under different climatic conditions.