The U.S. Geological Survey, in cooperation with the U.S. Air Force, collected ground-water samples and made water-level measurements from January through October 2000 to monitor natural attenuation at four sites in the East Management Unit of Dover Air Force Base in Kent County, Delaware. The information in this report is based on data from ground-water samples collected during two sampling events, which occurred from January through March 2000 and September through October 2000. Ground-water samples and water-level measurements were collected from 36 monitor wells during the first sampling event. During the second sampling event, groundwater samples were collected from 34 monitor wells and water-level measurements were made in 29 monitor wells. Water-level measurements were also made in 103 wells during a synoptic in March 2000. The analytical results from the groundwater samples, the water-level measurements, and data-collection techniques are presented in this report. Analytical results indicate that the U.S. Environmental Protection Agency's maximum contaminant levels for constituents analyzed were exceeded in 10 samples collected during the first sampling event and 11 samples collected during the second sampling event. An independent quality-assurance data validation indicated that the water-quality data collected during this study were of good quality, reproducible, and unbiased.
