An example expert system for the interpretation of depositional environments

During 1983 the U.S. EPA requested the U.S. Geological Survey and the Missouri Department of Natural Resources to study the geology, water movement, and sediment characteristics of Sugar, Romaine, and Rock Creek basins in Jefferson County, Missouri. The information was needed because the EPA had confirmed the presence of dioxin contamination at Bubbling Spring Horse Arena and on properties in Romaine and Rock Creek basins. Streambed sampling in the upstream reaches of Romaine Creek shows that dioxin is leaving the sites. Because dioxin strongly adsorbs onto fine sediments, it is believed to be transported with the sediments by water erosion. Sediment yields from two sampling sites along Romaine Creek generally were small during base-flow periods; however, instantaneous storm-runoff sediment discharges as large as 1.7 lbs/sec occurred at the downstream site. Typical instantaneous sediment discharges during storm-runoff sampling ranged from