Attachment 0002_Well Drillers Log.pdf

This document is a geological survey record and well drilling log from the Illinois State Geological Survey for a water well located at Rock Island Arsenal in Rock Island County, Illinois. The well was drilled on July 1, 1941, by Thorpe Well Drilling Company and reached a total depth of 1,603 feet. The well is situated at coordinates 41.519567 latitude and -90.54522 longitude, with an elevation of 570 feet above ground level, located 1,700 feet south and 700 feet west of the section line in Township 30-18N-1W. The API number is 121610032400, and the county permit number is 00324.

The driller's log documents subsurface geology encountered during drilling, beginning with soil and limestone at the surface and progressing through multiple strata including sandstone, shale, and various limestone formations to the final depth. Key geological formations identified include the Maquoketa Group (top at 406 feet), Galena Formation (629 feet), St. Peter Sandstone (1,025 feet), and Knox Formation (1,066 feet). Water was first encountered at 90 feet in limestone with a static water level of 42 feet 6 inches and a measured drawdown of 104 feet 11 inches at 1,291 gallons per minute. The well construction details include multiple casing and liner installations at specified depths, with the final configuration featuring a 13-inch hole at the bottom and concrete grouting at the surface and intermediate depths.