Measurement of Solute Transport from an Earthen Reserve Pit During Drilling and Post Closure Operational Phases: Part I. Site Characteristics and Experimental Design

Abstract This paper reports the construction and experimental design of the first known instrumented earthen reserve pit. The instrumentation allowed the measurement of solute transport from a field reserve pit during drilling operations and after pit closure. The field study, conducted in Brazos County Texas, shows the limitations and advantages of the various instrumentation techniques utilized. Accordingly, other investigators can avoid use of inappropriate or unnecessary monitoring devices. Additionally, limited field data are discussed. The field study, which is the basis for this paper, consists of 3 parts: Site Characteristics and Experimental Design, Field Measurement, and Laboratory Analyses and Interpretation. This paper presents the Site characteristics and Experimental design for the reserve pit. No other field study attempts to capture solute migrating from a reserve pit, measure the chemical constituents and explain the mechanism impeding or excluding contaminant migration. The authors rely on lysimeters, soil moisture cups, monitoring wells, and electrical resistance sensors in obtaining the field data. The lysimeters and soil moisture cups function well. However, the moisture cups provide more useable data. The resistance sensors provided no useable data. Parameter analyses for soil cores taken in the pit area at pre-drilling and post-closure operational phases correlated well with soil water monitoring device data, substantiating the observations of insignificant solution migration. Further, the data are confirmed by analyzing monitoring well data over a period of more than 2 years.