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Courtney Killian

Courtney is a hydrologist with the Pennsylvania Water Science Center in the Bridgeville, Pennsylvania office where she investigates groundwater and water quality.

Courtney’s current work includes quantifying available groundwater resources with the use of machine-learning techniques to map groundwater quality across an aquifer in three dimensions. This work helps to identify areas where poor water quality may limit the use of fresh water for agricultural, industrial, and drinking water uses. 

Courtney also applies machine-learning techniques to predict groundwater levels through time at ungaged locations across an aquifer. Courtney's research has included groundwater and surface-water interaction studies, low-flow groundwater quality sampling for age tracers, isokinetic depth-integrated surface-water sampling, and nuclear magnetic resonance borehole and surface imaging. She enjoys using R and Python programming in conjunction with GIS to help answer regional water availability questions. 

 

Education and Certifications

  • Mississippi State University, 2016-18, Doctor of Philosophy, Earth and Atmospheric Science

  • Mississippi State University, 2013-15, Master of Science, Geoscience

  • California University of Pennsylvania, 2009-2013, Bachelor of Science, Geology

  • Registered Professional Geologist no. 998, State of Mississippi, 2020 – Present

  • Geospatial and Remote Sensing Technologies Certification, Mississippi State University, 2015

     

Affiliations and Memberships*

  • Geological Society of America, 2012 – Present

     

Honors and Awards

  • U.S. Department of the Interior Star Award, 2018

     

Abstracts and Presentations

  • Killian, C., and Knierim, K.J., 2021, Incorporating airborne electromagnetic survey data into machine-learning models to predict groundwater salinity in the Mississippi River Valley Alluvial aquifer: Geological Society of America Abstracts with Programs, v. 53, no. 6, https://doi.org/10.1130/abs/2021AM-364652.

  • Asquith, W., and Killian, C. (presenter), 2021, Covariate builder and machine learning modeling software to predict groundwater levels for the Mississippi River Valley alluvial aquifer, Geological Society of America Abstracts with Programs, v. 53, no. 6, https://doi.org/10.1130/abs/2021AM-365803.

  • Killian, C., and Knierim, K.J., 2020, Using machine-learning predictions of groundwater salinity to assess water availability in the Mississippi River Valley alluvial aquifer, Geological Society of America Abstracts with Programs.

  • Killian, C., Bussell, A., Knierim, K.J., Wacaster, S., and Gratzer, M., 2020, Groundwater quality and age to address water availability in the Mississippi River Valley Alluvial Aquifer, Technical Presentation, Mississippi Water Resources Conference, Jackson, MS.

  • Killian, C., Bussell, A., Knierim, K.J., Kingsbury, J., Wacaster, S., Kress, W.H., 2019, Mapping the Variability of Specific Conductance in Groundwater of the Mississippi River Valley Alluvial Aquifer, Technical Presentation, Mississippi Water Resources Conference, Jackson, MS.

  • Killian, C., Adams, R.F., Rigby, J.R., Leaf, A. Barlow, J.R.B., Kress, W.H., Schmitz, D.W., 2018, Evaluation of Methods for Relating Continuous Streambed Resistivity Data and Hydraulic Conductivity in the Mississippi Delta, Technical Presentation, Mississippi Water Resources Conference, Jackson, MS.

  • Killian, C., Barlow, J.R.B., Barlow, P., Kress, W.H., Schmitz, D.W., 2018, Groundwater and Surface-Water Interaction Characterization of the Mississippi Delta Using Hydrograph- Separation Techniques and Trend Analyses, Technical Presentation, 82nd Annual Meeting, Mississippi Academy of Sciences, Hattiesburg, MS.

  • Killian, C., Barlow, J.R.B., Barlow, P., Kress, W.H., Schmitz, D.W., 2017, Characterizing Groundwater and Surface-Water Interaction in the Mississippi Delta Using Hydrograph Separation, Technical Presentation, National Ground Water Association, Nashville, TN.

  • Killian, C., Barlow, J.R.B., Barlow, P., Kress, W.H., Schmitz, D.W., 2017, Characterizing groundwater and surface-water interaction throughout the Mississippi Delta using hydrograph-separation techniques combined with near-stream geophysical and groundwater-level data, Technical Presentation, Mississippi Water Resources Conference, Jackson, MS.

     

Science and Products

Assessment of Hydrologic Trends in Pennsylvania

The U.S. Geological Survey (USGS) in cooperation with the Pennsylvania Department of Conservation and Natural Resources (PA DCNR), Bureau of Geological Survey, provides time series trends results using the Mann Kendall family of analyses on select sites across Pennsylvania for baseflow, runoff, groundwater levels, and streamflow percentiles. Trend results for baseflow and runoff at 197 sites acros
By
Pennsylvania Water Science Center

Statistical predictions of groundwater levels and related spatial diagnostics for the Mississippi River Valley alluvial aquifer from the mmlMRVAgen1 statistical machine-learning software

A multiple machine-learning model (Asquith and Killian, 2024) implementing Cubist and Random Forest regressions was used to predict monthly mean groundwater levels through time for the available years described in the metadata for the Mississippi River Valley alluvial aquifer (MRVA). The MRVA is the surficial aquifer of the Mississippi Alluvial Plain (MAP), located in the south-central United Stat
By
Pennsylvania Water Science Center

Quality assurance of water levels in the Mississippi River Valley alluvial aquifer in Louisiana from the Louisiana Department of Natural Resources' Strategic Online Natural Resources Information System (SONRIS)

This data release provides several data files representing groundwater levels reported through driller's reports for the State of Louisiana Department of Natural Resources (Louisiana Department of Natural Resources, 2023) within or near the Mississippi Alluvial Plain (MAP) and (or) associated with the Mississippi River Valley alluvial aquifer (MRVA). First, a retrieval of data from the State of Lo
By
Pennsylvania Water Science Center

Quality assurance of water levels in the Mississippi River Valley alluvial aquifer in Arkansas from the Arkansas Department of Agriculture Natural Resources Division

This data release provides several data files representing groundwater levels reported through driller's reports for the State of Arkansas Arkansas Department of Agriculture National Resources Division (https://wise.er.usgs.gov/driller_db/) (accessed January 10, 2024) within or near the Mississippi Alluvial Plain (MAP) and (or) associated with the Mississippi River Valley alluvial aquifer (MRVA).
By
Pennsylvania Water Science Center

Machine-learning model predictions and rasters of groundwater salinity in the Mississippi Alluvial Plain

Groundwater from the Mississippi River Valley alluvial aquifer (MRVA), coincident with the Mississippi Alluvial Plain (MAP), is a vital resource for agriculture and drinking-water supplies in the central United States. Water availability can be limited in some areas of the aquifer by high concentrations of salinity, measured as specific conductance. Boosted regression trees (BRT), a type of ensemb
By
Lower Mississippi-Gulf Water Science Center, Pennsylvania Water Science Center

Estimates of Baseflow, Runoff, and Groundwater Recharge Based on Streamflow-Hydrograph Methods: Pennsylvania

The U.S. Geological Survey (USGS) in cooperation with the Pennsylvania Department of Conservation and Natural Resources, Bureau of Geological Survey, estimated groundwater recharge by automated streamflow-hydrograph methods for watersheds throughout Pennsylvania. These data serve as an update to previous estimates of groundwater recharge described in Risser and others (2005). The current analysis
By
Pennsylvania Water Science Center

Groundwater levels and other covariates useful for statistical modeling for the Mississippi River Valley Alluvial aquifer, Mississippi Alluvial Plain

Groundwater-level data, in conjunction with attendant metadata and covariates (predictor variables) data, for the Mississippi River Valley alluvial aquifer (MRVA) are used to support statistical and process-based numerical modeling. This page represents a collection of groundwater-level data within the expanse of the Mississippi Alluvial Plain (MAP) (Painter and Westerman, 2018) and are derived fr
By
Lower Mississippi-Gulf Water Science Center

MODFLOW-2005 model used to evaluate water-management scenarios for the Mississippi Delta

A three-dimensional groundwater flow model (MODFLOW-2005) of the Mississippi embayment, South-Central United States, was developed as part of a national project initiated by the U.S. Geological Survey Groundwater Resources Program to provide updated assessments of groundwater availability in important principal aquifers across the United States. The goals of the national assessment are to document
By
Lower Mississippi-Gulf Water Science Center

Estimated and measured streamflow and groundwater-level data in the Mississippi Delta

This data release provides the data that support the findings in "Characterizing groundwater and surface-water interaction using hydrograph-separation techniques and groundwater-level data throughout the Mississippi Delta" by Killian and others (2019). There are two child items below: (1) Estimated baseflow includes the baseflow_est data and metadata that contain daily mean streamflow data provid
By
Lower Mississippi-Gulf Water Science Center

Machine-learning predictions of groundwater specific conductance in the Mississippi Alluvial Plain, south-central United States, with evaluation of regional geophysical aerial electromagnetic data as explanatory variables

The Mississippi Alluvial Plain, located in the south-central United States, is undergoing long-term groundwater-level declines within the surficial Mississippi River Valley alluvial aquifer (hereinafter referred to as “alluvial aquifer”), which has raised concerns about future groundwater availability. In some parts of the alluvial aquifer, groundwater availability for common uses such as irrigati
Authors
Courtney D. Killian, Katherine J. Knierim
By
Lower Mississippi-Gulf Water Science Center

Simulation of water-management scenarios for the Mississippi Delta

To compare the effectiveness of proposed alternative water-supply scenarios on future water availability in the Mississippi Delta, the U.S. Geological Survey and the Mississippi Department of Environmental Quality are collaborating on the update and enhancement of an existing regional groundwater-flow model of the area. Through this collaboration, the model has been updated to include boundary con
Authors
Connor J. Haugh, Courtney D. Killian, Jeannie R. B. Barlow
By
Lower Mississippi-Gulf Water Science Center

Characterizing groundwater/surface-water interaction using hydrograph-separation techniques and groundwater-level data throughout the Mississippi Delta, USA

The Mississippi Delta, located in northwest Mississippi, is an area dense with industrial-level agriculture sustained by groundwater-dependent irrigation supplied by the Mississippi River Valley Alluvial aquifer (alluvial aquifer). The Delta provides agricultural commodities across the United States and around the world. Observed declines in groundwater altitudes and streamflow contemporaneous wit
Authors
Courtney D. Killian, William H. Asquith, Jeannie R. B. Barlow, Gardner C. Bent, Wade Kress, Paul M. Barlow, Darrel W. Schmitz
By
Water Resources Mission Area, Groundwater and Streamflow Information Program, Oklahoma-Texas Water Science Center, New England Water Science Center, Lower Mississippi-Gulf Water Science Center

Non-USGS Publications**

Killian, C., Asquith, W.H., Barlow, J.R.B., Bent, G.C., Kress, W.H., Barlow, P.M., and Schmitz, D.W., 2019, Characterizing groundwater and surface-water interaction using hydrograph-separation techniques and groundwater-level data throughout the Mississippi Delta, USA: Hydrogeol. J, 27, 2167-2179, https://doi.org/10.1007/s10040-019-01981-6.
Killian, C., 2018, Characterizing spatial and temporal changes and driving factors of groundwater and surface-water interactions within the Mississippi portion of the Mississippi Alluvial Plain, Mississippi State University, Mississippi, https://hdl.handle.net/11668/21276.
Killian, C., 2015, Surface-water and groundwater interactions of a stream reach and proposed reservoir within the Pascagoula River Basin: George County, Mississippi: Mississippi State University, Mississippi, https://hdl.handle.net/11668/20516.
Killian, C. and Stoner, T., 2013, B-1112 Elementary Problems and Solutions: The Fibonacci Quarterly, 51 (3), 277-278.

**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.

mmlMRVAgen1, Source Code for Construction of Multiple Machine-Learning Models of Water Levels in the Mississippi River Valley Alluvial Aquifer

The mmlMRVAgen1 repository contains R, LaTeX, Mermaid, and Perl language source code that can be used for construction multiple methods of machine learning (MML) of water levels in the Mississippi River Valley alluvial aquifer (MRVA) within the Mississippi Alluvial Plain (MAP), south-central United States. The source code is written in R (primary and extensive), LaTeX (for structured narrative as
By
Lower Mississippi-Gulf Water Science Center

infoGWauxs, Auxiliary methods for infoGW and similar groundwater level data objects and other helpful utilities

The infoGWauxs package in the R language provides auxiliary methods for data merging, duplicate-record removal, and monthly rollup of groundwater levels in the so-called infoGW or GWmaster data objects. These data structures are particularly well suited for statistical analyses of groundwater levels. This package is part of a greater body of data processors oriented around the infoGW standard. The
By
Lower Mississippi-Gulf Water Science Center

covMRVAgen1, Source code for construction of covariates bound to monthly groundwater levels for purposes of statistical modeling of water levels in the Mississippi River Valley alluvial aquifer

The covMRVAgen1 repository contains R (primarily), Mermaid, Perl, and Python language source code that can be used the construction of input tables of monthly groundwater levels (response variable) and predictor variables (covariates) for statistical modeling of water levels in the Mississippi River Valley alluvial aquifer within the Mississippi Alluvial Plain, south-central United States. The sou
By
Lower Mississippi-Gulf Water Science Center

Science and Products

Assessment of Hydrologic Trends in Pennsylvania

The U.S. Geological Survey (USGS) in cooperation with the Pennsylvania Department of Conservation and Natural Resources (PA DCNR), Bureau of Geological Survey, provides time series trends results using the Mann Kendall family of analyses on select sites across Pennsylvania for baseflow, runoff, groundwater levels, and streamflow percentiles. Trend results for baseflow and runoff at 197 sites acros
By
Pennsylvania Water Science Center

Statistical predictions of groundwater levels and related spatial diagnostics for the Mississippi River Valley alluvial aquifer from the mmlMRVAgen1 statistical machine-learning software

A multiple machine-learning model (Asquith and Killian, 2024) implementing Cubist and Random Forest regressions was used to predict monthly mean groundwater levels through time for the available years described in the metadata for the Mississippi River Valley alluvial aquifer (MRVA). The MRVA is the surficial aquifer of the Mississippi Alluvial Plain (MAP), located in the south-central United Stat
By
Pennsylvania Water Science Center

Quality assurance of water levels in the Mississippi River Valley alluvial aquifer in Louisiana from the Louisiana Department of Natural Resources' Strategic Online Natural Resources Information System (SONRIS)

This data release provides several data files representing groundwater levels reported through driller's reports for the State of Louisiana Department of Natural Resources (Louisiana Department of Natural Resources, 2023) within or near the Mississippi Alluvial Plain (MAP) and (or) associated with the Mississippi River Valley alluvial aquifer (MRVA). First, a retrieval of data from the State of Lo
By
Pennsylvania Water Science Center

Quality assurance of water levels in the Mississippi River Valley alluvial aquifer in Arkansas from the Arkansas Department of Agriculture Natural Resources Division

This data release provides several data files representing groundwater levels reported through driller's reports for the State of Arkansas Arkansas Department of Agriculture National Resources Division (https://wise.er.usgs.gov/driller_db/) (accessed January 10, 2024) within or near the Mississippi Alluvial Plain (MAP) and (or) associated with the Mississippi River Valley alluvial aquifer (MRVA).
By
Pennsylvania Water Science Center

Machine-learning model predictions and rasters of groundwater salinity in the Mississippi Alluvial Plain

Groundwater from the Mississippi River Valley alluvial aquifer (MRVA), coincident with the Mississippi Alluvial Plain (MAP), is a vital resource for agriculture and drinking-water supplies in the central United States. Water availability can be limited in some areas of the aquifer by high concentrations of salinity, measured as specific conductance. Boosted regression trees (BRT), a type of ensemb
By
Lower Mississippi-Gulf Water Science Center, Pennsylvania Water Science Center

Estimates of Baseflow, Runoff, and Groundwater Recharge Based on Streamflow-Hydrograph Methods: Pennsylvania

The U.S. Geological Survey (USGS) in cooperation with the Pennsylvania Department of Conservation and Natural Resources, Bureau of Geological Survey, estimated groundwater recharge by automated streamflow-hydrograph methods for watersheds throughout Pennsylvania. These data serve as an update to previous estimates of groundwater recharge described in Risser and others (2005). The current analysis
By
Pennsylvania Water Science Center

Groundwater levels and other covariates useful for statistical modeling for the Mississippi River Valley Alluvial aquifer, Mississippi Alluvial Plain

Groundwater-level data, in conjunction with attendant metadata and covariates (predictor variables) data, for the Mississippi River Valley alluvial aquifer (MRVA) are used to support statistical and process-based numerical modeling. This page represents a collection of groundwater-level data within the expanse of the Mississippi Alluvial Plain (MAP) (Painter and Westerman, 2018) and are derived fr
By
Lower Mississippi-Gulf Water Science Center

MODFLOW-2005 model used to evaluate water-management scenarios for the Mississippi Delta

A three-dimensional groundwater flow model (MODFLOW-2005) of the Mississippi embayment, South-Central United States, was developed as part of a national project initiated by the U.S. Geological Survey Groundwater Resources Program to provide updated assessments of groundwater availability in important principal aquifers across the United States. The goals of the national assessment are to document
By
Lower Mississippi-Gulf Water Science Center

Estimated and measured streamflow and groundwater-level data in the Mississippi Delta

This data release provides the data that support the findings in "Characterizing groundwater and surface-water interaction using hydrograph-separation techniques and groundwater-level data throughout the Mississippi Delta" by Killian and others (2019). There are two child items below: (1) Estimated baseflow includes the baseflow_est data and metadata that contain daily mean streamflow data provid
By
Lower Mississippi-Gulf Water Science Center

Machine-learning predictions of groundwater specific conductance in the Mississippi Alluvial Plain, south-central United States, with evaluation of regional geophysical aerial electromagnetic data as explanatory variables

The Mississippi Alluvial Plain, located in the south-central United States, is undergoing long-term groundwater-level declines within the surficial Mississippi River Valley alluvial aquifer (hereinafter referred to as “alluvial aquifer”), which has raised concerns about future groundwater availability. In some parts of the alluvial aquifer, groundwater availability for common uses such as irrigati
Authors
Courtney D. Killian, Katherine J. Knierim
By
Lower Mississippi-Gulf Water Science Center

Simulation of water-management scenarios for the Mississippi Delta

To compare the effectiveness of proposed alternative water-supply scenarios on future water availability in the Mississippi Delta, the U.S. Geological Survey and the Mississippi Department of Environmental Quality are collaborating on the update and enhancement of an existing regional groundwater-flow model of the area. Through this collaboration, the model has been updated to include boundary con
Authors
Connor J. Haugh, Courtney D. Killian, Jeannie R. B. Barlow
By
Lower Mississippi-Gulf Water Science Center

Characterizing groundwater/surface-water interaction using hydrograph-separation techniques and groundwater-level data throughout the Mississippi Delta, USA

The Mississippi Delta, located in northwest Mississippi, is an area dense with industrial-level agriculture sustained by groundwater-dependent irrigation supplied by the Mississippi River Valley Alluvial aquifer (alluvial aquifer). The Delta provides agricultural commodities across the United States and around the world. Observed declines in groundwater altitudes and streamflow contemporaneous wit
Authors
Courtney D. Killian, William H. Asquith, Jeannie R. B. Barlow, Gardner C. Bent, Wade Kress, Paul M. Barlow, Darrel W. Schmitz
By
Water Resources Mission Area, Groundwater and Streamflow Information Program, Oklahoma-Texas Water Science Center, New England Water Science Center, Lower Mississippi-Gulf Water Science Center

Non-USGS Publications**

Killian, C., Asquith, W.H., Barlow, J.R.B., Bent, G.C., Kress, W.H., Barlow, P.M., and Schmitz, D.W., 2019, Characterizing groundwater and surface-water interaction using hydrograph-separation techniques and groundwater-level data throughout the Mississippi Delta, USA: Hydrogeol. J, 27, 2167-2179, https://doi.org/10.1007/s10040-019-01981-6.
Killian, C., 2018, Characterizing spatial and temporal changes and driving factors of groundwater and surface-water interactions within the Mississippi portion of the Mississippi Alluvial Plain, Mississippi State University, Mississippi, https://hdl.handle.net/11668/21276.
Killian, C., 2015, Surface-water and groundwater interactions of a stream reach and proposed reservoir within the Pascagoula River Basin: George County, Mississippi: Mississippi State University, Mississippi, https://hdl.handle.net/11668/20516.
Killian, C. and Stoner, T., 2013, B-1112 Elementary Problems and Solutions: The Fibonacci Quarterly, 51 (3), 277-278.

**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.

mmlMRVAgen1, Source Code for Construction of Multiple Machine-Learning Models of Water Levels in the Mississippi River Valley Alluvial Aquifer

The mmlMRVAgen1 repository contains R, LaTeX, Mermaid, and Perl language source code that can be used for construction multiple methods of machine learning (MML) of water levels in the Mississippi River Valley alluvial aquifer (MRVA) within the Mississippi Alluvial Plain (MAP), south-central United States. The source code is written in R (primary and extensive), LaTeX (for structured narrative as
By
Lower Mississippi-Gulf Water Science Center

infoGWauxs, Auxiliary methods for infoGW and similar groundwater level data objects and other helpful utilities

The infoGWauxs package in the R language provides auxiliary methods for data merging, duplicate-record removal, and monthly rollup of groundwater levels in the so-called infoGW or GWmaster data objects. These data structures are particularly well suited for statistical analyses of groundwater levels. This package is part of a greater body of data processors oriented around the infoGW standard. The
By
Lower Mississippi-Gulf Water Science Center

covMRVAgen1, Source code for construction of covariates bound to monthly groundwater levels for purposes of statistical modeling of water levels in the Mississippi River Valley alluvial aquifer

The covMRVAgen1 repository contains R (primarily), Mermaid, Perl, and Python language source code that can be used the construction of input tables of monthly groundwater levels (response variable) and predictor variables (covariates) for statistical modeling of water levels in the Mississippi River Valley alluvial aquifer within the Mississippi Alluvial Plain, south-central United States. The sou
By
Lower Mississippi-Gulf Water Science Center

*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

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