A hydrologic study of the Big Sioux aquifer system was begun July 1, 1966, by the U.S. Geological Survey, in cooperation with the City of Sioux Falls and the East Dakota Conservancy Sub-District.
Test drilling being done in the search for a southern outlet to the Big Sioux aquifer has led to the discovery of the outlet and of a deeper aquifer than was previously know to exist in this area. This aquifer, herein called the Sioux Falls aquifer, was first recognized as a very clean gravel in test hole USGS #1 between the depths of 60 to 83 feet.
Subsequent test drilling and aquifer testing has shown the Sioux Falls aquifer to be capable of producing several hundred gallons of water per minute. THe chemical quality of this water surpasses that currently being used for the city supply.
Further investigation of the aquifer is planned as a part of the continuing expansion of the water-supply facilities for Sioux Falls.
This publication has been authorized by the Director of the U.S. Geological Survey and Earl McCart, Commissioner, City of Sioux Falls, South Dakota.