Track B-1. Groundwater supply and planning: Aquifers
Comparing shallow groundwater quality in Kane County between 2003 and 2015
Walt Kelly, Illinois State Water Survey
In October 2003, scientists from the Illinois State Water Survey (ISWS) sampled 75 shallow wells for water quality analysis in Kane County to provide a snapshot of groundwater quality in these shallow aquifers and to compare water quality from different parts of aquifers in Kane County. In the fall of 2015, the study was repeated to assess how groundwater quality had changed since 2003. Sixty-eight wells were sampled in 2015, 55 of which had been sampled in 2003. The quality of shallow groundwater in Kane County is generally good, especially in the western half of the county. However, the total dissolved solids (TDS) values in samples from the urban corridor in the eastern part of the county were significantly higher than elsewhere in the county—chloride was the ion of greatest concern. Two-thirds of the samples from the eastern wells sampled had TDS or chloride concentrations above drinking water standards. Road salt runoff is most likely the major source of elevated TDS and chloride. Of the wells sampled in both 2003 and 2015, about 60 percent had higher TDS values in 2015, with three having increases greater than 100 mg/L. The average increase for the wells with increasing TDS values was 50 mg/L. The increase in TDS is entirely explained by increases in chloride and sodium concentrations, which increased in 78 percent and 59 percent of the wells, respectively. The average increase for wells with increasing values was 25.4 mg/L for chloride and 19.2 mg/L for sodium. The average rate of increase in chloride concentrations in the urban eastern third of Kane County was 3.9 mg/L/yr, which is similar to rates found in other studies in northeastern Illinois.
Walt Kelly is a groundwater geochemist who has been at ISWS since 1992. He is also currently the head of the Groundwater Science Section. He is an adjunct professor in the Department of Geology and Geography at Illinois State University. He has a master of arts in geological sciences from Case Western Reserve University and a PhD in environmental sciences from the University of Virginia. His research interests are primarily related to groundwater quality, and he is an author on more than 80 reports and peer-reviewed papers.
Long-term groundwater monitoring: Turning research from more than 20 years ago into a continual source of valuable information
Steve Wilson and Kevin Rennels, Illinois State Water Survey
In the 1990’s, two major aquifer characterization programs were initiated to better understand the Mahomet Aquifer. The Imperial Valley Water Authority funded the development of an observation well and rain gauge network in the western portion of the Mahomet Aquifer in Mason and Tazewell counties. The Long Range Water Plan Steering Committee funded an aquifer characterization study that included installing monitoring wells in Tazewell, Logan, and McLean counties. Today, over 20 years later, the wells are still monitored, most with continuous recording equipment. The information gathered from these wells has been instrumental in modeling efforts in the Mahomet Aquifer as well as understanding the effects of short-term events, such as irrigation in the summer months, water quality issues in parts of the Mahomet Aquifer, and how rainfall affects recharge in the Havana Lowlands. How this data has been utilized and what we have learned from it will be described.
Steve Wilson is a groundwater hydrologist at ISWS. He has been in the Groundwater Science Section since 1983. Steve manages WaterOperator.org and PrivateWellClass.org, two federally funded programs that support small drinking water utilities and private well owners. Steve has a bachelor of science in agricultural science and agricultural engineering and a master of science in civil engineering, all from the University of Illinois.
The use of transducers and animations to observe water level trends in the Mahomet Aquifer near Champaign-Urbana
George Roadcap, Illinois State Water Survey
We can observe long-term trends in the Mahomet Aquifer and the response to individual hydrologic events, such as droughts or irrigation pumpage, by monitoring water levels. Collection of water level data with pressure transducers contributes greatly to the general understanding of flow and water use in the aquifer. Visual representation of the data with maps and animations also help to determine the principal influences on the aquifer, such as where major recharge areas exist. The long-term trend in water levels has remained fairly flat during the period from 2009 to 2014 with some small shifts in water levels as pumpage has increase at the new Bradley Avenue wellfield west of Champaign. In the short term, however, the aquifer has witnessed significant episodic drawdown due to pumpage by the City of Decatur and irrigators during the drought that started in 2011 and extended through 2012. The heavy seasonal water use in 2011 and the lack of storms in the winter of 2012 may have reduced the amount of stored groundwater in the watershed, and thus contributed to the no-flow conditions on the Sangamon River in the summer of 2012.
George Roadcap is a hydrogeologist with the Illinois State Water Survey, where his research is focused on a variety of groundwater quality and quantity issues. The focus of his recent research has been on constructing models to determine the long-term sustainability of water supplies. He received bachelor’s and doctoral degrees from the University of Illinois and a master’s degree from The Ohio State University.
Walt Kelly, Illinois State Water Survey
In October 2003, scientists from the Illinois State Water Survey (ISWS) sampled 75 shallow wells for water quality analysis in Kane County to provide a snapshot of groundwater quality in these shallow aquifers and to compare water quality from different parts of aquifers in Kane County. In the fall of 2015, the study was repeated to assess how groundwater quality had changed since 2003. Sixty-eight wells were sampled in 2015, 55 of which had been sampled in 2003. The quality of shallow groundwater in Kane County is generally good, especially in the western half of the county. However, the total dissolved solids (TDS) values in samples from the urban corridor in the eastern part of the county were significantly higher than elsewhere in the county—chloride was the ion of greatest concern. Two-thirds of the samples from the eastern wells sampled had TDS or chloride concentrations above drinking water standards. Road salt runoff is most likely the major source of elevated TDS and chloride. Of the wells sampled in both 2003 and 2015, about 60 percent had higher TDS values in 2015, with three having increases greater than 100 mg/L. The average increase for the wells with increasing TDS values was 50 mg/L. The increase in TDS is entirely explained by increases in chloride and sodium concentrations, which increased in 78 percent and 59 percent of the wells, respectively. The average increase for wells with increasing values was 25.4 mg/L for chloride and 19.2 mg/L for sodium. The average rate of increase in chloride concentrations in the urban eastern third of Kane County was 3.9 mg/L/yr, which is similar to rates found in other studies in northeastern Illinois.
Walt Kelly is a groundwater geochemist who has been at ISWS since 1992. He is also currently the head of the Groundwater Science Section. He is an adjunct professor in the Department of Geology and Geography at Illinois State University. He has a master of arts in geological sciences from Case Western Reserve University and a PhD in environmental sciences from the University of Virginia. His research interests are primarily related to groundwater quality, and he is an author on more than 80 reports and peer-reviewed papers.
Long-term groundwater monitoring: Turning research from more than 20 years ago into a continual source of valuable information
Steve Wilson and Kevin Rennels, Illinois State Water Survey
In the 1990’s, two major aquifer characterization programs were initiated to better understand the Mahomet Aquifer. The Imperial Valley Water Authority funded the development of an observation well and rain gauge network in the western portion of the Mahomet Aquifer in Mason and Tazewell counties. The Long Range Water Plan Steering Committee funded an aquifer characterization study that included installing monitoring wells in Tazewell, Logan, and McLean counties. Today, over 20 years later, the wells are still monitored, most with continuous recording equipment. The information gathered from these wells has been instrumental in modeling efforts in the Mahomet Aquifer as well as understanding the effects of short-term events, such as irrigation in the summer months, water quality issues in parts of the Mahomet Aquifer, and how rainfall affects recharge in the Havana Lowlands. How this data has been utilized and what we have learned from it will be described.
Steve Wilson is a groundwater hydrologist at ISWS. He has been in the Groundwater Science Section since 1983. Steve manages WaterOperator.org and PrivateWellClass.org, two federally funded programs that support small drinking water utilities and private well owners. Steve has a bachelor of science in agricultural science and agricultural engineering and a master of science in civil engineering, all from the University of Illinois.
The use of transducers and animations to observe water level trends in the Mahomet Aquifer near Champaign-Urbana
George Roadcap, Illinois State Water Survey
We can observe long-term trends in the Mahomet Aquifer and the response to individual hydrologic events, such as droughts or irrigation pumpage, by monitoring water levels. Collection of water level data with pressure transducers contributes greatly to the general understanding of flow and water use in the aquifer. Visual representation of the data with maps and animations also help to determine the principal influences on the aquifer, such as where major recharge areas exist. The long-term trend in water levels has remained fairly flat during the period from 2009 to 2014 with some small shifts in water levels as pumpage has increase at the new Bradley Avenue wellfield west of Champaign. In the short term, however, the aquifer has witnessed significant episodic drawdown due to pumpage by the City of Decatur and irrigators during the drought that started in 2011 and extended through 2012. The heavy seasonal water use in 2011 and the lack of storms in the winter of 2012 may have reduced the amount of stored groundwater in the watershed, and thus contributed to the no-flow conditions on the Sangamon River in the summer of 2012.
George Roadcap is a hydrogeologist with the Illinois State Water Survey, where his research is focused on a variety of groundwater quality and quantity issues. The focus of his recent research has been on constructing models to determine the long-term sustainability of water supplies. He received bachelor’s and doctoral degrees from the University of Illinois and a master’s degree from The Ohio State University.
