Vadose zone monitoring

Dr. Oscar E. Meinzer, in his tome entitled, Hydrology, which was first presented by the National Research Council in 1942, referred to the vadose zone as ‘no man’s land’. From 1942 through the formation of the US Environmental Protection Agency (EPA) in 1970, the vadose zone was fundamentally ignored. The first major national groundwater monitoring contract was awarded by EPA in 1972, on a sole-source basis, to General Electric’s ‘TEMPO’ in Santa Barbara, California. In the years 1974–76, it became clear to the research team that groundwater investigations could not ‘black box’ the vadose zone. This initial effort resulted in a 15-step groundwater monitoring methodology published by Todd et al. (1976) and Everett (1980). Fundamental to this national strategy was an appreciation of contaminant transport through various parts of the vadose zone.