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Tissa H. Illangasekare

AMX Distinguished Chair of Environmental Sciences
Professor, Civil and Environmental Engineering
Director, Center for the Experimental Study of Subsurface Environmental Processes

Tissa IllangasekareIllangasekare’s primary area of research is in modeling of flow and transport in permeable and fractured media. His research encompasses many areas that include numerical modeling of saturated and unsaturated flow in soils, surface-subsurface interaction, arid-zone hydrology, integrated hydrologic modeling, flow in subfreezing snow, transport of dissolved and multiphase wastes, wireless sensor networking for environmental monitoring and intelligent remediation and environmental impacts of energy development. His research combines basic theories describing fundamental processes, numerical models and experiments that are conducted at a hierarchy of scales from small laboratory cells to intermediate scale test systems that includes a coupled porous media/ low velocity boundary layer environmental wind tunnel.

His early research on stream-aquifer interaction helped to develop conjunctive use management models for a number of river basins in Colorado. Research he has conducted in surface hydrology has helped to develop methods to estimate floods in un-gaged watersheds and one of the methods proposed by USBR to develop hydrologic hazard curves for the dam safety and decision criteria. The models he has developed to simulate both laminar and turbulent flow in fractured media have been used in dam safety analysis. His research on water infiltration in sub-freezing snow has lead to the development of models to predict meltwater generation in arctic glaciers including the Greenland to predict future sea level change. His fundamental research on flow and entrapment behavior of organic chemical wastes and petroleum products and mass transfer under both natural and remedial action has contributed to improve conceptual models that have lead to develop better models, characterization methods, monitoring schemes, up-scaling methods and remediation design. More recently he has extended his research into looking at emerging problems in the shallow subsurface, the zone of the unsaturated zone just below the ground surface bounded by the atmospheric boundary layer. This research will help to address problems in buried threat detection, CO2 sequestration, and land-atmospheric interaction modeling.


Coolbaugh Hall 310


  • PhD in Civil Engineering, Colorado State University, 1978 Colorado State University, Fort Collins, Colorado
  • MEng in Hydrology and Water Resources Engineering, 1974 Asian Institute of Technology, Bangkok, Thailand
  • BSc (honors) in Civil Engineering, 1971 University of Ceylon, Peradeniya, Sri Lanka
  • Honorary Doctorate in Science and Technology, Uppsala University, Sweden, 2010

Selected Publications

  • Illangasekare, T. H. and H.J. Morel-Seytoux, 1982. Stream-Aquifer Influence Coefficients for Simulation and Management, Water Resources Research, (18(1), pp. 168 176
  • Illangasekare, T.H. Walter, R.J. Jr., M.F. Meier and W.T. Pfeffer, 1990. Modeling of meltwater infiltration in subfreezing snow, Water Resources Research, 26(5), 1001 1012.
  • Pfeffer, T., M. Meier and T. H. Illangasekare, Retention of Greenland runoff by refreezing; implications for projected future sea level change, J. of Geophysical Research, 96(C12), p22,117 22,124, 1991.
  • Amadei, B. and T.H. Illangasekare, 1994. A mathematical model for flow and solute transport in non-homogeneous rock fractures, Int. J. of Rock Mech. and Min. Sci..Volume 31, Issue 6, December 1994, Pages 719-731
  • Illangasekare, T.H., J. L. Ramsey, K.H. Jensen and M. Butts, 1995. Experimental study of movement and distribution of dense organic contaminants in heterogeneous aquifers, J. of Contaminant Hydrology, 20, 1-25.
  • Held R.J., and T.H. Illangasekare, 1995. Fingering of dense non-aqueous phase liquids in porous media 1. Experimental Investigation, Water Resources Resh., 31(5),1213-1222.
  • Pieper, A.P., J.N. Ryan, R.W. Harvey, T.H. Illangasekare, G.L. Amy and D.W. Metge, 1997. Transport and recovery of bacteriophage PRD1 in an unconfined sand aquifer: effect of sewage-derived organic matter, Environmental Science and Technology, 31(4), 1163-1173.
  • Saba. T and T.H. Illangasekare (2000). Effect of groundwater flow dimensionality on mass transfer from entrapped nonaqueous phase liquids, Water Res. Resh, 36(4),971-979.
  • Chao, H-C, H. Rajaram and T.H. Illangasekare (2000). Intermediate scale experiments and numerical simulations of transport under radial flow in two-dimensional heterogeneous porous medium, Water Res. Resh,36(10), 2869-2878.
  • Fern√†ndez-Garcia D., H. Rajaram, T. H. Illangasekare, 2005. Assessment of the predictive capabilities of stochastic theories in a three-dimensional laboratory test aquifer: Effective hydraulic conductivity and temporal moments of breakthrough curves, Water Resour. Res., 41, W04002, doi:10.1029/2004WR003523
  • Saenton, S and T.H. Illangasekare, 2007. Up-scaling of mass transfer rate coefficient for the numerical simulation of DNAPL dissolution in heterogeneous aquifers, Water Resources Resh. 43, W02428.
  • Phenrat, T.; Kim, H.-J.; Fagerlund, F.; Illangasekare, T.; Lowry, G. V. (2010). Empirical Correlations to Estimate Agglomerate Size and Deposition during Injection of a Polyelectrolyte-modified Fe0 Nanoparticle at High Particle Concentration in Saturated Sand. Journal of Contaminant Hydrology, 118 (3-4) pp 152-164
  • V. Bandara, A. P. Jayasumana, A. Pezeshki, T. H. Illangasekare and K. Barnhardt, “Subsurface Plume Tracking Using Sparse Wireless Sensor Networks,” Electronic Journal of Structural Engineering (EJSE) – Special Issue: Wireless Sensor Networks and Practical Applications, 2010.

Awards and Honors

  • Langbein Lecture Award (Bowie lecture) by the American Geophysical Union’s Bowie Lectures (2015)
  • Henry Darcy Medalist by the European Geoscience Union (EGU) (2012)
  • Honorary Doctorate for Science and Technology, Uppsala University, Sweden (2010)
  • Fellow of American Geophysical Union
  • Fellow of American Association for Advancement of Science
  • Fellow of American Society of Cvil Engineers
  • Fellow of the Soil Science Society of America
  • Past Editor, Water Resources Research
  • Past co-editor, Vadose Zone Journal
  • President- International Society for Porous Media (2017-2019)
  • Fellow of National Academy of Science of Sri Lanka (2017)
    • Distinguished Alumni Award -Asian Institute of Technology, Thailand (2017)
    • Appointed by President Obama to the Nuclear Waste Technology Review Board (2017-2020)
  • PSIPW International Groundwater Prize (awarded at the UN by Secretary General Ban Ki-Moon, 2016)