Quality of shallow ground water in alluvial aquifers of the Willamette Basin, Oregon, 1993-95

The current (1993-95) quality of shallow ground water inWillamette Basin alluvium is described using results from two studies. A Study-Unit Survey, or regional assessment of shallow groundwater quality in alluvium, was done from June through August 1993. During the Study-Unit Survey, data were collected from 70 domestic wells chosen using a random-selection process and located mostly in areas of agricultural land use. An urban Land-Use Study, which was a reconnaissance of shallow urban ground-water quality from 10 monitoring wells installed in areas of residential land use, was done in July 1995. Concentrations of nitrite plus nitrate, phosphorus, pesticides and their degradation products, volatile organic compounds, arsenic and radon were measured.