Amy M Gahala
Amy Gahala is a hydrologist at Central Midwest Water Science Center at the DeKalb, Illinois Office.
Amy joined the USGS in 2011 and has devoted her career to studying groundwater hydrographs for a countywide network of about 40 monitoring wells continuously collecting water levels. Her investigations also include water quality with a focus on collecting continuous specific conductance for monitoring chloride trends in the groundwater. Amy is also involved in groundwater investigations and water balance studies in Iowa. Amy also reviews data, reports, and proposals for the U.S. Environmental Protection Agency.
Professional Experience
2011 to Present USGS, Hydrologist, Central Midwest Water Science Center, DeKalb, Illinois
Education and Certifications
M.S. in Geology, Northern Illinois University, 2011
B.S. in Geology and Environmental Geosciences, Northern Illinois University, 2009
Affiliations and Memberships*
2011-2018, Illinois Groundwater Association, Illinois (2018 Chair)
Science and Products
Groundwater Monitoring in McHenry County, Illinois
Groundwater Monitoring in McHenry County, Illinois
Seepage Meter Data Collected at Crystal Lake, City of Crystal Lake, Illinois, 2020
Seepage meters measurements were collected at three locations along the northern shoreline and at three locations along the southern shoreline of Crystal Lake, located in the City of Crystal Lake, Illinois on October 28-30, 2020, and November 4-5, 2020. Seepage measurements directly measure the flux for the area captured by the seepage meter. A positive (gaining) flux is assumed when the volume in
Reconnaissance of Per- and Polyfluoroalkyl Substances (PFAS) in Selected Groundwater and Surface Water Sites in McHenry County, Illinois, 2020
Data were collected at 19 groundwater monitoring wells and 3 surface water locations across McHenry County, Illinois, in 2020 by staff from the U.S. Geological Survey (USGS) Central Midwest Water Science Center. Quality control samples (2 blanks and 1 replicate) were also collected to assess data reliability and precision. Samples were submitted to the USGS National Water Quality Laboratory in Den
Quality-Assurance and Quality-Control Data for Discrete Water-Quality Samples Collected in McHenry County, Illinois, 2020
In June and July of 2020, 45 groundwater wells in McHenry County, Illinois, were sampled for water quality (field properties, major ions, nutrients, and trace metals) and 12 wells were sampled for contaminants of emerging concern (pharmaceuticals, pesticides, and wastewater indicator compounds). Quality-assurance and quality-control samples were collected during the June and July 2020 sampling tha
Water level data from single-well (slug) tests at a monitoring well in Big Marsh, Chicago, Illinois
This data release contains hydraulic conductivity data from single well (slug) tests conducted from the slag-filled material of the open interval of monitoring well 37N14E-13.3a1 (MW2, United States Geological Survey [USGS] site number 414121087335701), Big Marsh, Chicago, Illinois, to calculate groundwater discharge into nearby ponds. Six mechanical slug tests were conducted on October 27, 2016,
Simulation of groundwater and surface-water interaction and lake resiliency at Crystal Lake, City of Crystal Lake, Illinois
The U.S. Geological Survey, in cooperation with the City of Crystal Lake, Illinois, started a study to increase understanding of groundwater and surface-water interaction between the glacial aquifer and the city’s namesake lake, Crystal Lake, and the effect of higher and lower precipitation conditions on groundwater and lake levels. The results from this study could be used by the city and others
Authors
Amy M. Gahala, Emilia L. Bristow, Jennifer B. Sharpe, Benjamin G Metcalf, Lisa A. Matson
Hydrology and water quality of a dune-and-swale wetland adjacent to the Grand Calumet River, Indiana, 2019–22
Adverse ecological and water-quality effects associated with industrial land-use changes are common for littoral wetlands connected to river mouth ecosystems in the Grand Calumet River-Indiana Harbor Canal Area of Concern. These effects can be exacerbated by recent high Lake Michigan water levels that are problematic for wetland restoration. Wetlands in the adjacent Clark and Pine Nature Preserve
Authors
Shawn Naylor, Amy M. Gahala
Statewide sampling to determine spatial distribution, prevalence, and occurrence of per- and polyfluoroalkyl substances (PFAS) in Illinois community water supplies, 2020–21
Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals that have been manufactured and used globally since the 1940s. PFAS are used for their oil- and water-repellent properties, ability to reduce friction, and their flame-retardant nature. PFAS are widely used in a variety of products, including clothing, carpet, food packaging, and firefighting foam. The properties that ma
Authors
Amy M. Gahala, Jennifer B. Sharpe, Andrew M. Williams
Water quality of sand and gravel aquifers in McHenry County, Illinois, 2020 and comparisons to conditions in 2010
McHenry County, Illinois, obtains most of its drinking water from shallow sand and gravel aquifers (groundwater). To evaluate this groundwater resource, the U.S. Geological Survey, in cooperation with McHenry County, Illinois, collected water-quality samples from 41 of 42 monitoring wells in the McHenry County Groundwater Monitoring Network and 4 monitoring wells from the U.S. Geological Survey Na
Authors
Amy M. Gahala, Lance R. Gruhn, Jennifer C. Murphy, Lisa A. Matson
Conceptual and numerical groundwater flow model of the Cedar River alluvial aquifer system with simulation of drought stress on groundwater availability near Cedar Rapids, Iowa, for 2011 through 2013
Between July 2011 and February 2013, the City of Cedar Rapids observed water level declines in their horizontal collector wells approaching 11 meters. As a result, pumping from these production wells had to be halted, and questions were raised about the reliability of the alluvial aquifer under future drought conditions. The U.S. Geological Survey, in cooperation with the City of Cedar Rapids, com
Authors
Adel E. Haj, Wonsook S. Ha, Lance R. Gruhn, Emilia L. Bristow, Amy M. Gahala, Joshua F. Valder, Carole D. Johnson, Eric A. White, Shelby P. Sterner
Hydrologic balance, water quality, chemical-mass balance, and geochemical modeling of hyperalkaline ponds at Big Marsh, Chicago, Illinois, 2016–17
Hyperalkaline (pH greater than 12) ponds and groundwater exist at Big Marsh near Lake Calumet, Chicago, Illinois, a site used by the steel industry during the mid-1900s to deposit steel- and iron-making waste, in particular, slag. The hyperalkaline ponds may pose a hazard to human health and the environment. The U.S. Geological Survey (USGS), in cooperation with the Environmental Protection Agency
Authors
Amy M. Gahala, Robert R. Seal, Nadine M. Piatak
Hydrologic Influences on Water Levels at Three Oaks Recreation Area, Crystal Lake, Illinois, April 14 through September 27, 2016
Hydrologic influences on water levels were investigated at Three Oaks Recreation Area (TORA), a former sand-and-gravel quarry converted into recreational lakes in Crystal Lake, Illinois. From 2009 to 2015, average water levels in the lakes declined nearly 4 feet. It was not clear if these declines were related to variations in weather (precipitation or evaporation) or other hydrologic influences s
Authors
Amy M. Gahala
Assessment of water resources in areas that affect the habitat of the endangered Hine’s emerald dragonfly in the Lower Des Plaines River Valley, Illinois
Review of previous investigations indicates that potential decreases in groundwater recharge and increased groundwater extraction in the vicinity of the Lower Des Plaines River Valley in Will County, Illinois, may reduce the amount of groundwater flow in the Silurian aquifer in this area. Groundwater discharge from the Silurian aquifer to wetlands in the Lower Des Plaines River Valley plays an imp
Authors
Robert T. Kay, Amy M. Gahala, Clinton Bailey
Hydrogeology and water quality of sand and gravel aquifers in McHenry County, Illinois, 2009–14, and comparison to conditions in 1979
Baseline conditions for the sand and gravel aquifers (groundwater) in McHenry County, Illinois, were assessed using data from a countywide network of 44 monitoring wells collecting continuous water-level data from 2009–14. In 2010, water-quality data were collected from 41 of the monitoring wells, along with five additional monitoring wells available from the U.S. Geological Survey National Water
Authors
Amy M. Gahala
Evaluation of aquifer interconnection from aquifer characteristics computed by using specific capacity data within the vicinity of the Tremont Barrel Fill site, Clark County, Ohio
The Tremont Barrel Fill site is immediately north of the Tremont City Landfill near Tremont City, Clark County, Ohio. The site was an unlined pit used as a repository for disposing industrial liquid wastes and sludge from 1976 through 1979. Previous investigations led the U.S. Environmental Protection Agency (USEPA) to conclude that the site poses a contamination risk to nearby residents relying o
Authors
Amy M. Gahala
Non-USGS Publications**
Leal-Bautista, R.A., Lenczewski, M., Morgan, C., Gahala, A., McLain, J.E., 2013, Assessing Fecal Contamination in Groundwater from the Tulum Region, Quintana Roo, Mexico, Journal of Environmental Protection, vol 4, p. 1272-1279 DOI: 10.4236/jep.2013.411148
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Groundwater Monitoring in McHenry County, Illinois
Groundwater Monitoring in McHenry County, Illinois
Seepage Meter Data Collected at Crystal Lake, City of Crystal Lake, Illinois, 2020
Seepage meters measurements were collected at three locations along the northern shoreline and at three locations along the southern shoreline of Crystal Lake, located in the City of Crystal Lake, Illinois on October 28-30, 2020, and November 4-5, 2020. Seepage measurements directly measure the flux for the area captured by the seepage meter. A positive (gaining) flux is assumed when the volume in
Reconnaissance of Per- and Polyfluoroalkyl Substances (PFAS) in Selected Groundwater and Surface Water Sites in McHenry County, Illinois, 2020
Data were collected at 19 groundwater monitoring wells and 3 surface water locations across McHenry County, Illinois, in 2020 by staff from the U.S. Geological Survey (USGS) Central Midwest Water Science Center. Quality control samples (2 blanks and 1 replicate) were also collected to assess data reliability and precision. Samples were submitted to the USGS National Water Quality Laboratory in Den
Quality-Assurance and Quality-Control Data for Discrete Water-Quality Samples Collected in McHenry County, Illinois, 2020
In June and July of 2020, 45 groundwater wells in McHenry County, Illinois, were sampled for water quality (field properties, major ions, nutrients, and trace metals) and 12 wells were sampled for contaminants of emerging concern (pharmaceuticals, pesticides, and wastewater indicator compounds). Quality-assurance and quality-control samples were collected during the June and July 2020 sampling tha
Water level data from single-well (slug) tests at a monitoring well in Big Marsh, Chicago, Illinois
This data release contains hydraulic conductivity data from single well (slug) tests conducted from the slag-filled material of the open interval of monitoring well 37N14E-13.3a1 (MW2, United States Geological Survey [USGS] site number 414121087335701), Big Marsh, Chicago, Illinois, to calculate groundwater discharge into nearby ponds. Six mechanical slug tests were conducted on October 27, 2016,
Simulation of groundwater and surface-water interaction and lake resiliency at Crystal Lake, City of Crystal Lake, Illinois
The U.S. Geological Survey, in cooperation with the City of Crystal Lake, Illinois, started a study to increase understanding of groundwater and surface-water interaction between the glacial aquifer and the city’s namesake lake, Crystal Lake, and the effect of higher and lower precipitation conditions on groundwater and lake levels. The results from this study could be used by the city and others
Authors
Amy M. Gahala, Emilia L. Bristow, Jennifer B. Sharpe, Benjamin G Metcalf, Lisa A. Matson
Hydrology and water quality of a dune-and-swale wetland adjacent to the Grand Calumet River, Indiana, 2019–22
Adverse ecological and water-quality effects associated with industrial land-use changes are common for littoral wetlands connected to river mouth ecosystems in the Grand Calumet River-Indiana Harbor Canal Area of Concern. These effects can be exacerbated by recent high Lake Michigan water levels that are problematic for wetland restoration. Wetlands in the adjacent Clark and Pine Nature Preserve
Authors
Shawn Naylor, Amy M. Gahala
Statewide sampling to determine spatial distribution, prevalence, and occurrence of per- and polyfluoroalkyl substances (PFAS) in Illinois community water supplies, 2020–21
Per- and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals that have been manufactured and used globally since the 1940s. PFAS are used for their oil- and water-repellent properties, ability to reduce friction, and their flame-retardant nature. PFAS are widely used in a variety of products, including clothing, carpet, food packaging, and firefighting foam. The properties that ma
Authors
Amy M. Gahala, Jennifer B. Sharpe, Andrew M. Williams
Water quality of sand and gravel aquifers in McHenry County, Illinois, 2020 and comparisons to conditions in 2010
McHenry County, Illinois, obtains most of its drinking water from shallow sand and gravel aquifers (groundwater). To evaluate this groundwater resource, the U.S. Geological Survey, in cooperation with McHenry County, Illinois, collected water-quality samples from 41 of 42 monitoring wells in the McHenry County Groundwater Monitoring Network and 4 monitoring wells from the U.S. Geological Survey Na
Authors
Amy M. Gahala, Lance R. Gruhn, Jennifer C. Murphy, Lisa A. Matson
Conceptual and numerical groundwater flow model of the Cedar River alluvial aquifer system with simulation of drought stress on groundwater availability near Cedar Rapids, Iowa, for 2011 through 2013
Between July 2011 and February 2013, the City of Cedar Rapids observed water level declines in their horizontal collector wells approaching 11 meters. As a result, pumping from these production wells had to be halted, and questions were raised about the reliability of the alluvial aquifer under future drought conditions. The U.S. Geological Survey, in cooperation with the City of Cedar Rapids, com
Authors
Adel E. Haj, Wonsook S. Ha, Lance R. Gruhn, Emilia L. Bristow, Amy M. Gahala, Joshua F. Valder, Carole D. Johnson, Eric A. White, Shelby P. Sterner
Hydrologic balance, water quality, chemical-mass balance, and geochemical modeling of hyperalkaline ponds at Big Marsh, Chicago, Illinois, 2016–17
Hyperalkaline (pH greater than 12) ponds and groundwater exist at Big Marsh near Lake Calumet, Chicago, Illinois, a site used by the steel industry during the mid-1900s to deposit steel- and iron-making waste, in particular, slag. The hyperalkaline ponds may pose a hazard to human health and the environment. The U.S. Geological Survey (USGS), in cooperation with the Environmental Protection Agency
Authors
Amy M. Gahala, Robert R. Seal, Nadine M. Piatak
Hydrologic Influences on Water Levels at Three Oaks Recreation Area, Crystal Lake, Illinois, April 14 through September 27, 2016
Hydrologic influences on water levels were investigated at Three Oaks Recreation Area (TORA), a former sand-and-gravel quarry converted into recreational lakes in Crystal Lake, Illinois. From 2009 to 2015, average water levels in the lakes declined nearly 4 feet. It was not clear if these declines were related to variations in weather (precipitation or evaporation) or other hydrologic influences s
Authors
Amy M. Gahala
Assessment of water resources in areas that affect the habitat of the endangered Hine’s emerald dragonfly in the Lower Des Plaines River Valley, Illinois
Review of previous investigations indicates that potential decreases in groundwater recharge and increased groundwater extraction in the vicinity of the Lower Des Plaines River Valley in Will County, Illinois, may reduce the amount of groundwater flow in the Silurian aquifer in this area. Groundwater discharge from the Silurian aquifer to wetlands in the Lower Des Plaines River Valley plays an imp
Authors
Robert T. Kay, Amy M. Gahala, Clinton Bailey
Hydrogeology and water quality of sand and gravel aquifers in McHenry County, Illinois, 2009–14, and comparison to conditions in 1979
Baseline conditions for the sand and gravel aquifers (groundwater) in McHenry County, Illinois, were assessed using data from a countywide network of 44 monitoring wells collecting continuous water-level data from 2009–14. In 2010, water-quality data were collected from 41 of the monitoring wells, along with five additional monitoring wells available from the U.S. Geological Survey National Water
Authors
Amy M. Gahala
Evaluation of aquifer interconnection from aquifer characteristics computed by using specific capacity data within the vicinity of the Tremont Barrel Fill site, Clark County, Ohio
The Tremont Barrel Fill site is immediately north of the Tremont City Landfill near Tremont City, Clark County, Ohio. The site was an unlined pit used as a repository for disposing industrial liquid wastes and sludge from 1976 through 1979. Previous investigations led the U.S. Environmental Protection Agency (USEPA) to conclude that the site poses a contamination risk to nearby residents relying o
Authors
Amy M. Gahala
Non-USGS Publications**
Leal-Bautista, R.A., Lenczewski, M., Morgan, C., Gahala, A., McLain, J.E., 2013, Assessing Fecal Contamination in Groundwater from the Tulum Region, Quintana Roo, Mexico, Journal of Environmental Protection, vol 4, p. 1272-1279 DOI: 10.4236/jep.2013.411148
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government