Determination of Altitude with the Aneroid Barometer

As an integral part of its program of geologic and ground-water studies, the Iowa Geological Survey in cooperation with the United States Geological Survey has for many years systematically collected and analyzed drill cuttings and related information from water wells and other boreholes drilled throughout Iowa. The usefulness of these data is increased greatly by determining the exact location and land-surface altitude of the well sites. As most well samples are collected at approximately 5-foot intervals during the drilling operation and as depth measurements by many well drillers are not precise, land-surface altitudes having an accuracy of 5 feet are satisfactory for most purposes. The time and personnel available for this work prohibits the use of precise leveling instruments on the scale necessary for maximum coverage throughout the State. These instruments, of course, are essential where altitude work of a precise nature is needed in a small area