The motivation of Smits' research group is to provide answers to questions of importance to many current and emerging water resources, hydrology, environmental and climate change related problems. These include understanding climate change, water and food supply, the transport of pollutant through soils, the leakage of geologically sequestered CO2 and methane gas through the unsaturated zone to the land surface, the detection of unexploded ordinances and geothermal energy storage systems.
The basic aim of Smits' research is to combine theoretical, numerical and experimental approaches to address hydrological processes occurring near the earth's surface as influenced by natural boundary conditions (e.g. humidity, temperature, radiation, wind, vegetation). Her group's main focus is to develop and test theories using multiscale models (e.g. more detailed fully coupled models and less detailed coarse scale models) validated by a range of laboratory and field-scale experiments.
Synopsis: A critical challenge for Land Surface Models (LSMs) is to properly simulate processes at the surface and the subsurface and their feedbacks to the atmosphere. Even given the same climate forcing, LSMs predict different surface fluxes and soil moisture conditions. Increasing confidence in climate predictions requires revisiting process understanding and using that understanding to improve model representation of critical land-atmosphere feedbacks. We are addressing this challenge by exploring our understanding and modeling of mass and energy exchange at the land-atmosphere interface over a wide range of scales, providing new insights into mass and thermal flux process interactions that will ultimately lead to better predictive models and characterization methods.
Funding Sources: National Science Foundation, Deutsche Forschungsgemeinschaft (DFG)
Synopsis: Natural gas (NG) pipeline safety has greatly improved in recent decades but incidents still occur, oftentimes associated with aging infrastructure, excavation and human error. Pipeline leakage which results in gas buildup and migration though soil and ultimately its release into the air or a substructure (e.g. basement) can be catastrophic. What is not well understood in pipeline leakage incidents, is how the environmental conditions affected the gas migration behavior. Our work is addressing this challenge by trying to better understand the conditions that cause gas migration, and how we can account for such factors in our decision making.
Funding Sources: Advanced Research Projects Agency-Energy (ARPA-E) Methane Observation Networks with Innovative Technology to Obtain Reductions (MONITOR), Research Partnership to Secure Energy for America (RPSEA)
Synopsis: In this work, we investigate the engineering challenges, environmental impacts, and implementation strategies for soil borehole thermal energy storage (SBTES) of thermal energy from renewable energy sources in the shallow subsurface (20 to 50 meters). Although SBTES systems in the vadose zone have been empirically assessed in pilot projects, their design and operation are oftentimes not guided by validated analyses which consider the physics of heat and mass transfer in the vadose zone. The objective of this research is to seek the optimum scalable energy storage efficiency for SBTES using numerical simulations validated with field- and laboratory-scale experiments. This project is a collaborative effort between University of Colorado, Boulder and Colorado School of Mines.
Funding Sources: National Science Foundation
Synopsis: Many variables such as soil type, climate, topography, and vegetation make detection and removal of landmines difficult. Detecting small mines in large areas is especially difficult when the area is highly heterogeneous with features that can mask the presence of the mine. Mine detection success depends on a number of factors that include burial depth, moisture content, soil heterogeneity, mine properties, as well as the time of day during when the scanning is performed. The goal of this research is to investigate how buried objects, geological features and different types of environmental excitations (e.g. air moisture, temperature, wind speed) affect spatial and temporal distributions of moisture and temperature in the soil. This information can be used to better understand, model/simulate, and predict the environmental conditions that are most dynamic to mine detection performance.
Funding Sources: Army Research Office and U.S. Army, Corps of Engineers Research and Development Center (ERDC)
Synopsis: Volatilization of organic compounds in the subsurface produce vapor plumes that can migrate horizontally and vertically throughout the unsaturated zone, possibly entering into residential or commercial buildings through a process known as vapor intrusion (VI). In this work, we study vapor generation and VI, using carefully controlled experiments in multiscale test systems in an effort to improve VI screening models and generally aid remediation site managers with the assessment of risk, and the selection of alternative remediation strategies.
Funding Sources: Strategic Environmental Research and Development Program (SERDP)