Natural airflow through the Apache Leap tuff near Superior, Arizona

• Main Author: Smith, Stewart James,1956-
• Other Authors: Evans, Daniel D.
• Language: en
• Published: The University of Arizona. 1989
• Online Access: http://hdl.handle.net/10150/192020

Significant natural airflow occurs in two boreholes tapping unsaturated, fractured tuff at the Apache Leap Tuff Site near Superior, Arizona. Flow rate and direction through the more productive hole and atmospheric pressure and temperature were monitored during periods from December 1987 through June 1988. A strong correlation between flow velocity and atmospheric pressure exists at time scales of minutes to months, while the effect of temperature on flow is manifested by a seasonal reversal in net flow direction. Net outward flow occurs in winter, reversing to net inward flow by late spring. The observed flow pattern is consistent with that observed at Yucca Mountain, Nevada, which is similar both lithologically and topographically to the Apache Leap Site. The effect of natural airflow on moisture distribution and gaseous radionuclide transport within the tuff should be considered in assessing the suitability of similar sites for high-level waste disposal.