Bare soil evaporation at Kesterson Reservoir, Merced County, California: Estimation by physical and chemical methods.

摘要

Soil and water contamination at Kesterson Reservoir, Merced County, California, by selenium and salts has been an environmental concern for several years. The complex speciation and transport paths of these contaminants in the soil system have been the subject of intense research. The potential for further salt and selenium redistribution in the soil profile due to evaporation, transpiration, and infiltration of water needs to be seriously considered in evaluating the present and future environmental risks. This research project was designed to focus on the process of bare soil evaporation as a likely mechanism for concentrating species at and near the soil surface. To that end, bare soil evaporation rates were measured directly in the field and estimated based on chemical changes in the soil system. The nature of the bare soil evaporation process was examined through empirical and numerical means. Based on changes in near-surface concentrations of salts and selenium over a twelve month period, predictions have been made for likely future changes in species distribution. 120 refs., 110 figs., 11 tabs.