My research group is focused on the application of geophysical methods to quantifying flow and transport within the vadose zone.  Topics of interest include locating and quantifying recharge, characterizing surface water/groundwater interactions, quantifying root water uptake, and monitoring transient processes in natural environments and landfills.  The methods that my students are examining are listed below.  These techniques are evaluated using hydrologic and geophysical numerical models.  In addition, the potential application of these methods is examined through basin scale numerical modeling.  For further information on my students, follow the link at the bottom of this page.
 

Basin Scale Numerical Modeling

Jesse Dickenson is examing the physical properties of basins that control the preservation of climatic signals in groundwater levels.  Abbie Faust is applying a basin scale model to identify the most likely locations of recharge in the Tucson Basin. Anastasia Olander is measuring the hydraulic properties of intact cores for use in a numerical model of recharge beneath ephemeral streams in the Sierra Vista subwatershed.

Collaborators:  Alan Flint, Randy Hanson, Don Pool, Alissa Coes, Stan Leake.

Borehole Ground Penetrating Radar

Dale Rucker is examing the spatial sensitivity of borehole ground penetrating radar instruments.  In addition, he is examining the use of neural networks to improve radar signal analysis. Gerd von Glinski used borehole GPR to monitor the response of an unconfined aquifer during pumping and recovery.

Electrical Resistivity Tomography

Alex Furman has applied the analytic element method to define the spatial sensitivity of ERT arrays.  He is using this result to optimize the choice of ERT arrays for rapid surveying and for more unique inversion.  Andrew Hinnell is coupling hydrologic and geophysical models to predict the utility of ERT for hydrologic monitoring and to improve hydrologic inversion based on ERT measurements.

Collaborators:  Art Warrick.

Electromagnetic Induction

James Callegary is using surface and borehole EM induction methods to monitor infiltration beneath ephemeral streambeds.  In addition, he is investigating the spatial sensitivity of EM measurements and the influence of temperature variations on instrument response.

Collaborators:  Don Pool, Alissa Coes.

Temperature Profiling

Matt Bailey and Kyle Blasch used shallow temperature measurements to infer the rate of infiltration beneath Rillito Creek, an ephemeral stream in Tucson, at the onset, during and at the end of flow.  As part of his research, Kyle also developed a contact resistance sensor to improve the measurement of flow timing and duration.  Dave Lawler used shallow temperature measurements to identify the extent of intermittent reaches along the San Pedro River. Charles Dowman is using borehole temperature measurements to measure deep infiltration fluxes.

Collaborators:  John Hoffmann, Stan Leake.

Time Domain Reflectometry

I am continuing my investigations of the spatial sensitivity of TDR to dielectric permittivity and electrical conductivity.  I have extended this work to examine the effects of instrument spatial sensitivity on hydrologic inverse modeling.

Collaborators:  John Knight, Henrik Nissen, Jirka Simunek.
 

Time Domain Transmission

Karen Masbruch developed an upward infiltration TDT method to characterize the dependence of the dielectric permittivity of municipal refuse on its water content to improve the application of TDR and GPR to landfill monitoring.  Chawn Harlow has developed a time gated TDT method to improve dielectric permittivity measurements in lossy media.  He is also applying this method to monitoring the water content of plant canopies.

Collaborators:  Eleanor Burke, Will Pockman.

Refereed Publications:

 (* DENOTES A STUDENT UNDER MY DIRECT SUPERVISION.)

Furman*, A., A. W. Warrick, and T.P.A. Ferré.  Electrical Potential Distributions in a Heterogeneous Subsurface in Response to Applied Current: Solution for Circular Inclusions.  Vadose Zone Journal, vol. 1, 273-280.

Ferré, T.P.A., H.H. Nissen, and J. Šimunek.  The Effect of the Spatial Sensitivity of TDR on Inferring Soil Hydraulic Properties from Water Content Measurements Made During the Advance of a Wetting Front.  Vadose Zone Journal, vol. 1, 281-288. [Cover image of issue from this paper.]

Blasch*, K.W., T.P.A. Ferré, A.H. Christensen, and J.P. Hoffmann. A New Field Method to Determine Streamflow Timing Using Electrical Resistance Sensors.  Vadose Zone Journal, vol. 1, 289-299.

Ferré, P.A., J.H. Knight, D.L. Rudolph, and R.G. Kachanoski.  2000. A Numerically Based Analysis of the Sensitivity of Conventional and Alternative Time Domain Reflectometry Probes.  Water Resources Research, vol. 36, no. 9, 2461-2468.

Ferré, P.A. 2000.  Review of “Principles of Hydrogeology” by P. Hudack.  EOS, Trans. Am. Geophys. Union, vol. 81, no. 23, June 6, 256.

Ferré, P.A., D.L. Rudolph, and R.G. Kachanoski.  2000.  Identifying the Conditions Amenable to the Determination of Solute Concentrations with Time Domain Reflectometry.  Water Resources Research, vol. 36, no. 2, 633-636.

Ferré, P.A., J.H. Knight, D.L. Rudolph, and R.G. Kachanoski.  1998. The Sample Area of Conventional and Alternative Time Domain Reflectometry Probes.  Water Resources Research, vol. 34,  no. 11, 2971-2979.

Ferré, P.A., J.D. Redman, D.L. Rudolph, and R.G. Kachanoski.  1998.  The Dependence of the Electrical Conductivity Measured by Time Domain Reflectometry on the Water Content of a Sand.  Water Resources Research, vol. 34,  no. 5, 1207-1213.

Ferré, P.A., D.L. Rudolph, and R.G. Kachanoski.  1998.  The Water Content Response of a Profiling Time Domain Reflectometry Probe. Soil Science Society of America Journal, vol. 62, no. 4, 865-873.

Knight, J.H., P.A. Ferré, D.L. Rudolph, and R.G. Kachanoski.  1997.  The Response of a Time Domain Reflectometry Probe with Fluid-Filled Gaps around the Rods.  Water Resources Research, vol. 33, no. 6, 1455-1460.

Ferré, P.A., D.L. Rudolph, and R.G. Kachanoski.  1996.  Spatial Averaging of Water Content by Time Domain Reflectometry:  Implications for Twin Rod Probes with and without Dielectric Coatings.  Water Resources Research, vol. 32, no. 2, 271-279.
 

 (* DENOTES A STUDENT UNDER MY DIRECT SUPERVISION.)

Ferré, P.A., D.L. Rudolph, and R.G. Kachanoski.  The Electrical Conductivity Response of a Multilevel Time Domain Reflectometry Probe. (Accepted for publication in Soil Science Society of America Journal)

Harlow*, R.C., E.J. Burke, and T.P.A. Ferré.  Measuring Water Content in Saline Soils Using Impulse Time Domain Transmission Techniques.  (Accepted for publication in Vadose Zone Journal)

Nissen, H.H., P.A. Ferré, and P. Moldrup. Metal-coated Printed Circuit Board Time Domain Reflectometry Probes for Measuring Water and Solute Transport in Soil. (Accepted for publication in Water Resources Research)

Nissen, H.H., P.A. Ferré, and P. Moldrup. Time Domain Reflectometry Developments in Soil Science: I. Unbalanced Two-Rod Probe Spatial Sensitivity and Sampling Volume. (Accepted for publication in Soil Science)

Nissen, H.H., P.A. Ferré, and P. Moldrup. Time Domain Reflectometry Developments in Soil Science: II. Coaxial Flow Cell for Measuring Effluent Electrical Conductivity. (Accepted for publication in Soil Science)

Nissen, H.H., P.A. Ferré, and P. Moldrup. Time Domain Reflectometry Developments in Soil Science: III. Small-Scale Probe for Measuring Bulk Soil Electrical Conductivity. (Accepted for publication in Soil Science)
 

 (* DENOTES A STUDENT UNDER MY DIRECT SUPERVISION.)

Ferré, T.P.A. and J.A. Huisman.  Examination of the Choice of Dielectric Mixing Model for Estimating Volumetric Water Content from Electromagnetic Travel Time Measurements Made in Spatially Heterogeneous Media. (In submission to Water Resources Research)

Ferré, T.P.A., H.H. Nissen, J.H. Knight, and P. Moldrup.  The Sample Area of Two- and Three-rod Time Domain Reflectometry Probes for Electrical Conductivity Measurement.  (In submission to Water Resources Research)

Ferré, T.P.A., G. von Glinski*, and L. A. Ferré.  Monitoring the Maximum Depth of Drainage in Response to Pumping Using Borehole Ground Penetrating Radar.  (In submission to Vadose Zone Journal)

Furman*, A., T.P.A. Ferré, and A. W. Warrick.  A Sensitivity Analysis of Electrical-Resistance-Tomography Array Types Using Analytical Element Modeling.  (In submission to Vadose Zone Journal)

Harlow*, R.C., E.J. Burke, T.P.A. Ferré, J.C. Bennett, and W. J. Shuttleworth.  Measuring Spectral Dielectric Properties Using Gated Time Domain Transmission Measurements.  (In submission to Vadose Zone Journal)

Hook, W.R., T.P.A. Ferré, C.E. Bassey, and S. Stuchly.  Performance Limits of Time Domain Reflectometry and Time Domain Transmission Using Uncoated Rods in Saline Soils.  (In submission to Soil Science Society of America Journal)

Huisman, S., W. Bouten, J.A. Vrugt, and P.A. Ferré.  Accuracy of Frequency Domain Analysis Scenarios for the Determination of Complex Dielectric Permittivity.  (In submission to Water Resources Research)

Lawler*, D., K.W. Blasch*, T.P.A. Ferré, and S.A. Leake.  Using Streambed Temperature to Identify Perennial, Ephemeral, and Intermittent Reaches in the San Pedro River, Southeastern Arizona.  (In submission to Vadose Zone Journal)

Masbruch*, K. and T.P.A. Ferré.  A Time Domain Transmission Method for Determining the Dependence of the Dielectric Permittivity on Volumetric Water Content: An Application to Municipal Landfills.  (In submission to Vadose Zone Journal)

Nissen, H.H., P.A. Ferré, and P. Moldrup. The Sample Area of Two- and Three-rod Time Domain Reflectometry Probes.  (In submission to Water Resources Research)

Rucker, D.F.* and T.P.A. Ferré.  Near-Surface Water Content Estimation with Borehole Ground Penetrating Radar Using Critically Refracted Waves. (In submission to Vadose Zone Journal)
 

Book Chapters:

Ferré, P.A. and Topp, G.C. 1999. Time Domain Reflectometry Techniques for Soil Water Content and Electrical Conductivity Measurements.  Sensors Update, v. 7, Geopel ed., pp. 277-300.

Ferré, T.P.A., J.P. Hoffmann, D.R. Pool and S.A. Leake. Geophysical Methods for Recharge Estimation. USGS Circular, in preparation.

Ferré, P.A. and G.C. Topp. Time Domain Reflectometry in Water Content Measurement Methods. Methods of Soil Analysis, American Society of Agronomy, in press.

Ferré, P.A. and A.W. Warrick. Soil Physics and Hydrology:  Infiltration. Encyclopedia of Soils in the Environment, Academic Press, in submission.

Ferré, P.A. and A.W. Warrick. Soil Physics and Hydrology:  Soil Water Dynamics. Encyclopedia of Soils in the Environment, Academic Press, in submission.

Hoffman, J.P., K.W. Blasch*, and T.P.A. Ferré. Rillito Creek – Combined use of heat and soil water content to determine stream/ground-water exchanges, Rillito Creek, Tucson, Arizona. USGS Circular, in submission.

Topp, G.C. and P.A. Ferré. The Basis of Electromagnetic Methods: a Wave Equation Framework in Water Content Measurement Methods. Methods of Soil Analysis, American Society of Agronomy, in press.

Topp, G.C. and P.A. Ferré. Thermogravimetric Methods in Water Content Measurement Methods. Methods of Soil Analysis, American Society of Agronomy, in press.

Topp, G.C. and P.A. Ferré. Time Domain Reflectometry. Encyclopedia of Soils in the Environment, Academic Press, in submission.

Topp, G.C. and P.A. Ferré, editors. Water Content Measurement Methods. Methods of Soil Analysis, American Society of Agronomy, in press.