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Thom Hardy, Ph.D.

Department of Biology

Only two things are infinite, the universe and human stupidity, and I'm not sure about the former.
- Albert Einstein

Thom Hardy

Thom Hardy



Thom Hardy, Ph.D.




Chief Science Officer

The Meadows Center for Water and the Environment

phone: 512-245-6729

Fax: 512-245-7919


Department of Biology/The Meadows Center for Water and the Environment
Texas State University
San Marcos, TX 78666


The Art and Science of Instream Flows

Instream Flows is the art and science of collecting data in systems we cannot adequately sample using methods developed by committees of technically unqualified participants for organisms we know very little about in order to form concepts about processes we do not fully understand that we represent as mathematical abstractions that we cannot precisely analyze to determine their responses to indeterminate stresses we cannot accurately predict now let alone in the future all in such a way that society at large is given no reason to suspect the extent of our ignorance.

-Adopted from Anonymous





Ph. D. – Civil and Environmental Engineering, Utah State University

M. S. -- Aquatic Biology, University of Nevada at Las Vegas

B. S. – Biology, University of Nevada at Las Vegas

B. S. – Secondary Education, University of Nevada at Las Vegas


Research Interests

Instream Flow Assessment Methodologies

Multidisciplinary Assessment Methods for Watershed Planning

Remote Sensing of Aquatic and Riparian Corridors

Aquatic Ecosystem Dynamics


Courses Taught

Techniques in Aquatic Biology (BIO 4350/7369) - Syllabus


  • Perkin, J. S., Z. R. Shattuck, P. T. Bean, T. H. Bonner, E. Saraeva, and T. B. Hardy. 2010. Movement and microhabitat associations of Guadalupe bass in two Texas rivers. North American Journal of Fisheries Management 30:xx – xx.
  • Saraeva, E. and T.B. Hardy. 2009. Prediction of fisheries physical habitat values based on hydraulic geometry and frequency distributions of depth and velocity. Intl. J. River Basin Management Vol 7, No 1. (2009), pp 31-41.
  • Saraeva, E. and T. B. Hardy. 2009. Extrapolation of site-specific weighted usable area curves and instrem flow requirements to unmeasured streams within the Nooksack watershed in support of strategic watershed planning. Intl. J. River Basin Management Vol 7, No 1. (2009), pp 91-103.
  • Hardy, T.B., et al. 2006. Validation of chinook fry behavior based escape cover modeling in the lower Klamath River. International Journal of River Basin Management. Vol 4, Issue 3.
  • Hardy, T.B. and C. Addley. 2003. Instream Flow Assessment Modeling: Combining Physical and Behavioral-Based Approaches. Canadian Water Resources Journal. 28(2):1-10.
  • Gregory, P.J., et. al. (including Hardy, T.). 2002. Environmental consequences of alternative practices for intensifying crop production. Agric. Ecosyst. Environ. 88, 279-290.
  • Guensch, G.R., T.B. Hardy, and R.C. Addley. 2001. Validation of an Individual-Based, Mechanistic Habitat Selection Model for Drift-Feeding Salmonids. Canadian Journal of Fisheries and Aquatic Science. 58(3):446-457.
  • Hardy, T.B & Addley, R.C. 2006. Vertical integration of spatial and hydraulic data for improved habitat modelling using geographic information systems. In Acreman, M.C. (ed) Hydro-ecology: Riverine Ecological Response to Changes in Hydrological Regime, Sediment Transport, and Nutrient Loading. IAHS Publication X.
  • Goodwin, Peter and Thomas B. Hardy. 1999. Integrated Simulation of Physical, Chemical and Ecological Processes for River Management. Journal of Hydroinformatics. 01:1 33-58.
  • Gilver, D.J., R. Bryant and T. Hardy. 1999. Remote sensing of channel morphology and in-stream fluvial processes. Progress in Environmental Science. 1(3): 257-284.
  • Hardy, T.B. 1998. The Future of Habitat Modeling and Instream Flow Assessment Techniques. Regulated Rivers: Research and Management 14:405-420.
  • Hardy, T.B. 1995. Assessing Environmental Effects of Severe Sustained Drought. Water Resources Bulletin, American Water Resources Association. 31(5):867-875.
  • Kershner, J.L. and T.B. Hardy. 1992. The rules of the game for evaluation of FERC relicense proposals. Rivers: 2:4 342-345 pp.
  • Modde, T. and T. B. Hardy. 1992. Influence of Different Microhabitat Criteria on Salmonid Habitat Simulation. Rivers: 3:1 37-44 pp.
  • Bishop, A. B. , T. B. Hardy and B. D. Glabou. 1990. Analyzing instream flow tradeoffs for small hydropower development. RIVERS 1(3):173-182.
  • Valdez, R., P. Holden and T.B. Hardy. 1990. Habitat suitability index curves for humpback chub in the upper Colorado River Basin. Rivers 1(1):31-42.

Theses Directed

Craig Addley                  MS         A Mechanistic approach to Modeling Habit of Drift Feeding Salmonids

James Shoemaker        MS          Use of Multispectral Aerial Videography for Jurisdictional Delineation of Wetland Areas

Thomas Redd                 MS          Use of Airborne Multispectral Videography for the Classification and Delineation of Riparian Vegetation

Kiran Panja                   MS          Classification of Mesoscale Hydraulic Features Based on Spectral Analysis of Multispectral Aerial Videography

Jennifer Ludlow          MS            Comparison of Physical Habitat Simulation Models with Energetic Modeling for Habitat use in Drift Feeding Salmonids

Brent Crowther            MS           Delineation of Mesoscale Hydraulic Features, Subaqueous Sediments, Spawning Sites, and Riverine Bathymetry in the South Fork of the Salmon River     Utilizing  Multispectral, Airborne Videography

Michael Chulick           MS          Flow Dependant Relationships of Habitat Utilization for the Comal Fountain Darter (Plan B)

Karl Tarbet                    MS          Development and Evaluation of a Two Dimensional Hydraulic Model for Instream Flow Assessments

Nathan Bartz                 MS          Multidisciplinary Assessment of Instream Flows in the Comal River, Texas

Loni Johnson                 MS          Use of Multi-spectral Digital Imagery to Assess Channel Changes in the Salmon River in Response to Flooding.

Greg Guensch                MS          Validation of a Mechanistically-Based Habitat Model for Drift Feeding Salmonids

Nathan Kennard          MS           Development of a Rapid Assessment Protocol for Evaluation of Instream Flows

Jason Thompson         MS            A Methodology for Assessing Aquatic and Riparian Habitat Quality at the Watershed Scale

Hans Milliken               MS           Comparative Evaluation of R2-Cross and WinXS-Pro for Evaluating Instream Flow Protection Levels in River Systems

Craig Addley                PhD         Modeling of River Ecosystems:  A Dynamic Three-Dimensional Habitat Template at Scales Relevant to Fish

Leon Basdekas             PhD         Virgin River Operations Optimization Model

Anji Dodd                      PhD         Development of a Three-Dimensional Sediment Transport Model for Predicting Channel Topographies in Fish Habitat Modeling

Ekaterina Sareava      PhD         Development of an Instream Flow-Based Extrapolation Procedure for the Nooksack Watershed

Mikhail Bhol                 MS           Estimating Uncertainty in Fish Habitat Modeling using Two-Dimensional Hydraulics

Eric McKlesky             MS           Landscape Ecology Metrics As an Alternative to Suitability Criteria Based Habitat Modeling of Fish



Adrian Vogel - A systems approach to decision support for watershed resources: Cypress Creek watershed, Hays County, Texas

Sanyogita Andriyas – Application of individual based models to evaluate on-farm watering practices and crop production

Brian Hines - Understanding the Complex Life History Ecology of a Lacustrine Sucker for Conservation and Management

Emily Warren – How do you explain compliance failure of community water systems under the Safe Water Drinking Act?

Hussein Batt – Nutrient dynamics in a regulate wetland, Bear Lake, Utah

David Kikkert - Upstream migration of amphidromous shrimp in the Luquillo Experimental Forest, Puerto Rico: Temporal patterns and environmental cues

Madeline Merck – Water quality dynamics in a small inland stream from gold mining operations, Kanektok Alaska

Omar Alminagorta – Optimizing water allocation management for environmental purposes

Issaak Vasquez – Impact of land-applied biosolids on forage quality and water movement during rangeland restoration activities

Mark Schmelter – Verification and validation of 2-dimensional hydrodynamic models applied in instream flow assessments



   Pictures from the field: