Hydrogeology, water use, and simulated ground-water flow and availability in Campton township, Kane County, Illinois

Abstract

Several aquifers underlying Campton Township in Kane County, Illinois provide virtually all of the water supply to the residents of the township. These aquifers consist of layers of unconsolidated sand and gravel in the glacial drift; dolomite and shale of the Alexandrian Series and the Maquoketa Group (the Silurian-Maquoketa aquifer); dolomite of the Platteville and Galena Groups (the Galena-Platteville aquifer); and sandstones of the Glenwood Formation and the St. Peter Sandstone (the Ancell aquifer). In 2002, total withdrawals from these aquifers underlying Campton Township exceeded 1.36 million gallons day. Water-level altitudes in the shallow and deep glacial drift aquifers generally follow surface topography. Comparison of water levels measured in 1995 and 2002 does not indicate large (15 feet or more) water-level declines in these aquifers beneath most of the township. Water-level altitudes in the Silurian-Maquoketa aquifer generally decrease from west to east. The potentiometric surface of the aquifer follows the bedrock-surface topography in parts of the township, but local low water-level altitudes and large declines in water levels between 1995 and 2002 indicate that withdrawals from the Silurian-Maquoketa aquifer may exceed recharge in some areas. Water-level altitudes in wells completed in the Galena-Platteville aquifer vary by more than 300 ft. Large water-level declines in wells completed in the Galena-Platteville aquifer from 1995 to 2002 indicate that withdrawals from the Galena-Platteville and Silurian-Maquoketa aquifers exceed recharge in the northern part of the township. Water-level altitudes in wells completed in the Ancell aquifer are also highly variable. Although there is no indication of large water-level declines in Ancell aquifer between 1995 and 2002, historical data for one well completed in the aquifer indicate large water-level declines over a period of decades. Computer simulation of flow in the ground-water system indicates that most of the shallow ground water underlying the township is derived from precipitation near the ground-water divide in the western part of the township. Shallow recharge moves primarily through the glacial drift aquifers and the upper part of the Silurian-Maquoketa aquifer, with minimal flow into the Galena-Platteville and Ancell aquifers. Most of the water in the Ancell aquifer beneath the township originates as surface recharge in the area west of the township. Vertical recharge to the Ancell aquifer from the Galena-Platteville aquifer beneath the township is not substantial. The source of the water withdrawn from the Ancell is inflow through the aquifer from areas west of the township. About 10 percent of ground water flowing through the township in 2002 was withdrawn by wells, with 80 percent flowing through the township and discharging to surface water bodies, including the Fox River. Simulation of additional withdrawals from the Ancell aquifer to supply an additional 605 proposed homes indicates about 17 ft of drawdown in the aquifer in the vicinity of a production well, but virtually no drawdown in any of the overlying aquifers.