Comment on “Evaluation of Evapotranspirative Covers for Waste Containment in Arid and Semiarid Regions in the Southwestern USA”

Abstract

Landfill covers relying on a balance between soil water storage and evapotranspiration (ET) as the primary means to control drainage have been described in the recent paper by Scanlon et al. (2005) in the Vadose Zone Journal. These so-called Covers have been receiving considerable interest in the past few years as economically viable cover systems for landfills in arid and semi-arid environments (Hauser et al. 2001, Madalinksi et al. 2003) Scanlon et al. (2005) have provided a summary of their studies in Texas and New Mexico, demonstrating an acceptable performance of ET covers in minimizing drainage under their test conditions. Further, they illustrate with both measurement and modeling that capillary barriers (fine soils over coarse soils) similar in concept to those previously built and tested at Los Alamos, NM and Hanford, WA over the past 20 years, store more water than surface barriers that have uniform profiles.