Abstract by Peter Van Katwyk
Peter Van Katwyk
Effect of subsidence on Groundwater contamination
Subsidence, usually caused by the excessive pumping of groundwater in dry climates, has had negative effects on not only the surface topography, but potentially the groundwater underneath. The hypothesis being tested is that over-pumping causes a pressure differential resulting in leaching of harmful elements, specifically arsenic, into the groundwater from surrounding soil layers. The purpose of this study is to use chemical analyses done on groundwater wells from the Phoenix and Tucson areas in order to determine whether subsidence is causing water contamination. In the preliminary stages of this research, existing data retrieved by the USGS and EPA, with plans to collect data ourselves in the near future. To measure the amount of contamination of the groundwater source, arsenic and several other potentially harmful elements have been flagged and their concentrations used to determine whether the source is contaminated. With the maps and concentrations retrieved thus far and through future studies we can determine whether there is a correlation between subsidence levels and composition of the groundwater source.