Scott J Ikard
I am a licensed Professional Engineer with thirteen years of professional research and project engineering experience in geophysics, hydrogeology, and hydrology, with auxiliary experiences in fluvial geomorphology, civil, and geotechnical engineering.
Currently, I am a Hydrologist in the Geophysics unit of the United States Geological Survey's Texas Water Science Center, in Austin, Texas. I plan and perform applied research studies and projects that broadly encompass proposals development, geophysical and hydrologic survey planning, instrumentation, data acquisition, data processing, and publication of surface, waterborne, airborne, and borehole hydrogeophysical data. The goals of my applied work frequently include delineation and correlation of aquifer systems, geophysical assessments of local and regional surface and ground water exchange-flow patterns, quantification and uncertainty analysis of hydraulic and geophysical properties of the vadose zone, confined and unconfined aquifers throughout the world.
United States Geological Survey. GS1315-11 Hydrologist/Geophysicist. Austin, Texas 06/2014 – Present
- Oversight, site selection, planning and preparation, and coordination of groundwater conservation districts, river authorities, municipal and government agencies, and public stakeholders in research-drilling and near-surface hydrogeophysical projects.
- Planning, implementation, and oversight of waterborne and land-based geophysical field surveys using time and frequency domain electromagnetics, self-potential mapping, electric resistance tomography, seismic refraction, dilution gaging, water-level monitoring, differential global positioning systems, Calibrated surface and borehole geophysical and hydrologic instruments, and performed troubleshooting of logging instruments and data acquisition systems in the field.
- Performed field acquisition, pre-processing, inversion, and post-processing of vertical electrical soundings and transient electromagnetic soundings, as well as surface self-potential and electrical resistivity tomography data, to map alluvial and deep confined aquifers and produce conceptual hydro-stratigraphic models for groundwater flow modeling.
- Developed data-processing codes and algorithms for (a) automated hydro-stratigraphic interpretation and geo-electric correlations from geophysical well logs and drillers logs, (b) automated baseflow separation and recession analysis, (c) digital signal processing, (d) groundwater flow modeling, particle tracking, parameter estimation and uncertainty analysis, (e) 2D and 3D forward and inverse modeling of self-potential and DC resistivity data using finite elements, finite differences, and linear filter theory.
- Published innovative, novel research in peer-reviewed journals and USGS reports.
Science and Products
Investigation of Preferential Groundwater Seepage in the Ellenburger – San Saba Aquifer Using Geoelectric Measurements
Geoelectric and Seismic Characterization of the Precambrian Granite Gravel Aquifer, Llano Uplift, Central Texas
Time-lapse self-potential, electric resistivity tomography, streamflow, groundwater-level, and weather-station datasets for the lower Rio Grande, southeast New Mexico, May–October, 2022
Self-potential, electrical resistivity tomography, and water temperature and electrical conductivity data pertaining to the sources of groundwater at Krause Springs, Spicewood, Texas, February 4–15, 2019
Waterborne Self-potential Data, Surface-water Temperature and Conductivity Logging data, and Electric Resistivity Tomography Data Measured at East Fork Poplar Creek, Oak Ridge, Tennessee, January-March 2022.
Historical (1940–2006) and recent (2019–20) aquifer slug test datasets used to model transmissivity and hydraulic conductivity of the Mississippi River Valley alluvial aquifer from recent (2018–20) airborne electromagnetic (AEM) survey d
Waterborne Gradient Self-potential, Temperature, and Conductivity Logging of the Upper part of the Delaware River between Hancock and Port Jervis, New York, June-July 2021
Waterborne Gradient Self-potential, Temperature, and Conductivity Logging of the Rio Grande from Leasburg Dam State Park, New Mexico to Canutillo, Texas During Bank-Full Conditions, June-July 2020
Model Inputs and Outputs for Simulating and Predicting the Effects of Climate and Land-Use Changes on Thermal Springs Recharge: A System-Based Coupled Surface-water and Groundwater Model for Hot Springs National Park, Arkansas
Waterborne Gradient Self-potential, Temperature, and Conductivity Logging of Lake Travis, Texas, near the Bee Creek Fault, March-April 2020
Time-Domain Electromagnetic Data Used in the Assessment of the Freshwater/Saline-Water Transition Zone within the Hueco Bolson, Fort Bliss Area, El Paso, Texas 2017-2019
Investigation of Scale-dependent Groundwater/Surface-water Exchange in Rivers by Gradient Self-Potential Logging: Numerical Model and Field Experiment Data, Quashnet River, Massachusetts, October 2017 (ver. 2.0, November 2020)
Geoelectric and Seismic Data acquired in the Precambrian Granite Gravel Aquifer, Llano Uplift, Central Texas, May 2017 - August 2018
650-m Profiles of Self-Potential, Contact Resistance, and Electric Resistance Tomography Measurements Adjacent to Hamilton Creek, Burnet County, Texas, July 2017 - January 2018
Discrete streamflow measurements and waterborne self-potential logging of a 43-kilometer-long reach of the Elm Fork Trinity River upstream from Dallas, Texas
Geoelectric monitoring of the electric potential field of the Lower Rio Grande before, during, and after Intermittent Streamflow, May–October, 2022
A model of transmissivity and hydraulic conductivity from electrical resistivity distribution derived from airborne electromagnetic surveys of the Mississippi River Valley Alluvial Aquifer, Midwest USA
Geoelectric survey of the Granite Gravel aquifer, Llano Uplift, Central Texas, to determine locations for water wells
Waterborne gradient Self-Potential (WaSP) logging in the Rio Grande to map localized and regional surface and groundwater exchanges across the Mesilla Valley
Investigation of scale-dependent groundwater/surface-water exchange in rivers by gradient self-potential logging: Numerical modeling and field experiments
Effects of climate and land-use change on thermal springs recharge—A system-based coupled surface-water and groundwater-flow model for Hot Springs National Park, Arkansas
Gradient self-potential logging in the Rio Grande to identify gaining and losing reaches across the Mesilla Valley
Geochemical assessment of the Hueco Bolson, New Mexico and Texas, 2016–17
Preferential groundwater seepage in karst terrane inferred from geoelectric measurements
New insights into surface-water/groundwater exchanges in the Guadalupe River, Texas, from floating geophysical methods
New insights on scale-dependent surface-groundwater exchange from a floating self-potential Dipole
Non-USGS Publications**
**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
Investigation of Preferential Groundwater Seepage in the Ellenburger – San Saba Aquifer Using Geoelectric Measurements
Geoelectric and Seismic Characterization of the Precambrian Granite Gravel Aquifer, Llano Uplift, Central Texas
Time-lapse self-potential, electric resistivity tomography, streamflow, groundwater-level, and weather-station datasets for the lower Rio Grande, southeast New Mexico, May–October, 2022
Self-potential, electrical resistivity tomography, and water temperature and electrical conductivity data pertaining to the sources of groundwater at Krause Springs, Spicewood, Texas, February 4–15, 2019
Waterborne Self-potential Data, Surface-water Temperature and Conductivity Logging data, and Electric Resistivity Tomography Data Measured at East Fork Poplar Creek, Oak Ridge, Tennessee, January-March 2022.
Historical (1940–2006) and recent (2019–20) aquifer slug test datasets used to model transmissivity and hydraulic conductivity of the Mississippi River Valley alluvial aquifer from recent (2018–20) airborne electromagnetic (AEM) survey d
Waterborne Gradient Self-potential, Temperature, and Conductivity Logging of the Upper part of the Delaware River between Hancock and Port Jervis, New York, June-July 2021
Waterborne Gradient Self-potential, Temperature, and Conductivity Logging of the Rio Grande from Leasburg Dam State Park, New Mexico to Canutillo, Texas During Bank-Full Conditions, June-July 2020
Model Inputs and Outputs for Simulating and Predicting the Effects of Climate and Land-Use Changes on Thermal Springs Recharge: A System-Based Coupled Surface-water and Groundwater Model for Hot Springs National Park, Arkansas
Waterborne Gradient Self-potential, Temperature, and Conductivity Logging of Lake Travis, Texas, near the Bee Creek Fault, March-April 2020
Time-Domain Electromagnetic Data Used in the Assessment of the Freshwater/Saline-Water Transition Zone within the Hueco Bolson, Fort Bliss Area, El Paso, Texas 2017-2019
Investigation of Scale-dependent Groundwater/Surface-water Exchange in Rivers by Gradient Self-Potential Logging: Numerical Model and Field Experiment Data, Quashnet River, Massachusetts, October 2017 (ver. 2.0, November 2020)
Geoelectric and Seismic Data acquired in the Precambrian Granite Gravel Aquifer, Llano Uplift, Central Texas, May 2017 - August 2018
650-m Profiles of Self-Potential, Contact Resistance, and Electric Resistance Tomography Measurements Adjacent to Hamilton Creek, Burnet County, Texas, July 2017 - January 2018
Discrete streamflow measurements and waterborne self-potential logging of a 43-kilometer-long reach of the Elm Fork Trinity River upstream from Dallas, Texas
Geoelectric monitoring of the electric potential field of the Lower Rio Grande before, during, and after Intermittent Streamflow, May–October, 2022
A model of transmissivity and hydraulic conductivity from electrical resistivity distribution derived from airborne electromagnetic surveys of the Mississippi River Valley Alluvial Aquifer, Midwest USA
Geoelectric survey of the Granite Gravel aquifer, Llano Uplift, Central Texas, to determine locations for water wells
Waterborne gradient Self-Potential (WaSP) logging in the Rio Grande to map localized and regional surface and groundwater exchanges across the Mesilla Valley
Investigation of scale-dependent groundwater/surface-water exchange in rivers by gradient self-potential logging: Numerical modeling and field experiments
Effects of climate and land-use change on thermal springs recharge—A system-based coupled surface-water and groundwater-flow model for Hot Springs National Park, Arkansas
Gradient self-potential logging in the Rio Grande to identify gaining and losing reaches across the Mesilla Valley
Geochemical assessment of the Hueco Bolson, New Mexico and Texas, 2016–17
Preferential groundwater seepage in karst terrane inferred from geoelectric measurements
New insights into surface-water/groundwater exchanges in the Guadalupe River, Texas, from floating geophysical methods
New insights on scale-dependent surface-groundwater exchange from a floating self-potential Dipole
Non-USGS Publications**
**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.