Progress 07/01/02 to 09/30/04
Outputs We made the following major contributions to the W-188 Multistate Project: (1) Development of a physically-based model for hydraulic properties of fractured porous media. Standard models for hydraulic functions of partially saturated fractured porous media (FPM) often rely on macroscopic continuum representation and embrace constitutive relationships originally developed for homogeneous porous media to describe hydraulic behavior of dual (or multi) continua FPM. Such approaches lead to inconsistencies due to neglect of underlying physical processes governing liquid retention and flow in the vastly different pore spaces. We developed a framework that considers equilibrium liquid configurations in dual continuum pore space as the basis for calculation of liquid saturation and introduction of hydrodynamic considerations. FPM cross-sectional pore space is represented by a bimodal size distribution reflecting two disparate populations of matrix pores and fracture apertures
(with rough-walled surfaces). Three laminar flow regimes are considered. (2) Development of a physically-based model for pore space evolution in expansive clay soils. Changes in volume and pore space induced by the shrink-swell behavior of clay minerals present a challenge to predictive modeling of hydraulic properties of clayey soils. We developed a novel framework that combines physico-chemical processes with pore scale geometrical, hydrostatic, and hydrodynamic considerations toward prediction of constitutive hydraulic relationships for swelling porous media. In course of this project we introduced novel technology for measurement of hydraulic conductivity and swelling potential of expansive soils to the soil science community. (3) Investigation of flow and distribution of fluids in porous plant growth media in microgravity. Despite 20 years of plant research in space, we lack understanding of basic fluid distribution and flow through porous media in microgravity. Plants are
essential for closed life support systems on long duration space missions. Even though plants/crops would be grown in a protected habitat in transit vehicles or on the surface of Moon and Mars, the environment is hostile to growth unless conditions are carefully controlled. The added complication that methods and procedures for water and nutrient management are necessarily modified under micro- or reduced gravity conditions presents a unique challenge that has yet to be met. Within this collaborative project we were able to scientifically identify causes for limited progress with plant growth experiments in space, and to provide guidelines for the developed of engineered plant growth media for reduced gravity and coupling of rhizospheric processes. Results were disseminated through 9 refereed journal articles and book chapters, 5 conference proceedings, and numerous abstracts and presentations.
Impacts The potential impact of our contributions can be specified as follows: (1) The ability to predict seepage through fractured formations becomes increasingly important for the design of subsurface waste repositories such as the potential high-level nuclear waste repository at Yucca Mountain, Nevada. Our model can be utilized to predict potential seepage based on climatic conditions, thereby contributing to the design and safe operation of potential underground storage facilities. (2) Predictive capabilities of pore space changes and associated hydraulic properties are crucial for management of agricultural soils with appreciable amount of active clay minerals. Results of our efforts should significantly contribute to improved salinity and sodicity management practices in irrigated agricultural areas. Furthermore, insights gained from this study will enhance understanding of clay dispersion and surface sealing, and lead to improved management guidelines for prevention of
soil erosion and colloid facilitated transport of agrochemicals. (3) Understanding of fluid behavior under microgravity conditions allows the development of engineered plant growth media that will be used for NASA's advanced life support systems for future long-duration space missions.
Publications
- Tuller, M. and Or, D. 2004. Water retention and characteristic curve. In Hillel, D. (Ed.), Encyclopedia of Soils in the Environment, Volume 4, Elsevier Ltd., Oxford, U.K., pp. 278-289.
- Or, D., Tuller, M. and Wraith, J.M. 2004. Water potential. In Hillel. D. (Ed.), Encyclopedia of Soils in the Environment, Volume 4, Elsevier Ltd., Oxford, U.K., pp. 270-277.
- Or, D. and Tuller, M. 2004. Capillarity. In Hillel, D. (Ed.), Encyclopedia of Soils in the Environment, Volume 1, Elsevier Ltd., Oxford, U.K., pp. 155-163.
- Or, D., Tuller, M. and Jones, S.B. 2004. Liquid-Gas Interfacial Configurations in Angular Pores under Microgravity. Proceedings of the 9th Biennial ASCE Aerospace Division International Conference on Engineering, Construction, and Operations in Challenging Environments, March 7-10, League City, TX. ASCE, Reston, VG, pp. 346-353.
- Steinberg, S., Alexander, I., Or, D., Daidzic, N., Jones, S., Reddi, L., Tuller, M., Kluitenberg, G. and Xiao, M. 2004. Flow and Distribution of Fluid Phases Through Porous Plant Growth Media in Microgravity. Proceedings of the 9th Biennial ASCE Aerospace Division International Conference on Engineering, Construction, and Operations in Challenging Environments, March 7-10, League City, TX. ASCE, Reston, VG, pp. 325-332.
- Tuller, M. and Or, D. 2004. A Universal Slope for Soil Water Characteristic Curves at Low Water Content. SSSA Annual Meeting Abstracts, Oct. 31-Nov. 4, Seattle, WA. On CD, abstract 4821.
- Tuller, M. and Islam, M.R. 2004. Methods for monitoring solute transport. In J. Alvarez-Benedi and R. Munoz-Carpena, Eds. Soil - Water Solute Process Characterization: An integrated Approach, CRC Press, pp. 309-355.
- Viola, R., Tuller, M. and Islam, M.R. 2004. Microscopic Observations of Pore Space Geometry in Clay-Sand Mixtures under Varying Hydration States. SSSA Annual Meeting Abstracts, Oct. 31-Nov. 4, Seattle, WA. On CD, abstract 4546.
- Ghebrehawariat, K., Tuller, M. and Or, D. 2004. Saturated Hydraulic Conductivity and Volume Change of Clay-Sand Mixtures. SSSA Annual Meeting Abstracts, Oct. 31 - Nov. 4, Seattle, WA. On CD, abstract 4835.
- Islam, M.R., Tuller, M. and Steinberg, S.L. 2004. Chemical and Mineralogical Composition of Baked Ceramic Aggregates Used as Plant Growth Media in Space. SSSA Annual Meeting Abstracts, Oct. 31-Nov. 4, Seattle, WA. On CD, abstract 5991.
- Gebrenegus, T., Tuller, M. and Muhunthan, B. 2004. Visualization and Quantification of Spatial Phase Arrangement in Bentonite-Sand Mixtures with X-Ray Computed Tomography. SSSA Annual Meeting Abstracts, Oct. 31-Nov. 4, Seattle, WA. On CD, abstract 4860.
- Or, D., Jones, S.B., Tuller, M., Steinberg, S.L., Alexander, I., Daidzic, N., Reddi, L.N., Kluitenberg, G., Ogden, F.L. and Heinse, R. 2004. Unsaturated Flow in Zero Gravity - Lessons and Challenges. SSSA Annual Meeting Abstracts, Oct. 31-Nov. 4, Seattle, WA. On CD, abstract 5102.
- Heinse, R., Jones, S.B., Humphries, S.D., Mace, R.W., Steinberg, S.L., Tuller, M., Newman, R. and Or, D. 2004. Porous Media Water Retention and Saturated Hydraulic Conductivity During Parabolic Flight Induced Microgravity. SSSA Annual Meeting Abstracts, Oct. 31-Nov. 4, Seattle, WA. On CD, abstract 5867.
- Gebrenegus, T., Tuller, M. and Muhunthan, B. 2004. Visualization of Spatial and Transient Phase Distributions in Porous Materials with X-Ray Computed Tomography. INRA Environmental & Subsurface Science Symposium "Environmental and Subsurface Science Applied to Energy, Nuclear, and National Security Research", September 20-22, 2004, Spokane, WA, http://www.b-there.com/breg/esss04/Poster_Beyene.doc.
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Progress 01/01/03 to 12/31/03
Outputs After development of a geometrical pore space evolution model linked to hydration state, and introduction of hydrostatic and hydrodynamic considerations to model liquid retention, hydraulic conductivity, and swelling behavior of clay soils we conducted a comprehensive experiment series to evaluate effects of clay type, clay content, solution chemistry and solution concentration on swelling behavior and hydraulic properties. We employed a latest technology flexible wall permeameter and volume change apparatus to measure hydraulic conductivity and swelling properties of bentonite-sand mixtures. We used solutions varying in molarity and ion valence to investigate the effects of solution concentration and type. The measurements were performed for bentonite contents ranging from 0 to 100%. The measurements were used to refine our pore-scale model, and to develop a statistical upscaling scheme to predict sample-scale hydraulic behavior. In this context we started
measurements at the new WSU Computed Tomography (CT) facility to resolve and introduce anisotropic hydraulic behavior. A recent collaboration with the INEEL Geocentrifuge facility in Idaho Falls allows access to a relatively large centrifuge that allows measurements on large specimens. These measurements will lead to the development of and upscaling concept for prediction of profile-scale properties. These efforts are partially supported by a NSF-EPSCoR and an USGS-IWRRI grant. We continued to work on flow phenomena in structured soils that led to a refereed publication in Advances in Water Resources, and conducted KC135 flight experiments in Houston, TX to investigate liquid behavior in porous plant growth media under microgravity. The flight experimental data are used in combination with physically based models to design root modules and growth chambers suitable to support plant growth at the International Space Station and for other space exploration. This project is supported by
NASA. Research findings were disseminated through 2 refereed journal articles, 4 refereed book chapters, and numerous presentations at national and international symposia and meetings.
Impacts The project on swelling soils will significantly contribute to improved predictions of water flow and solute interactions in agricultural soils with appreciable amount of clay minerals, and lead to improved salinity and sodicity management practices in irrigated agricultural areas. Furthermore, insights gained from this study will enhance understanding of clay dispersion and surface sealing, and lead to improved management guidelines for prevention of soil erosion, and associated colloid facilitated transport of agrochemicals. In extreme cases, improved ability for prediction of the onset of surface runoff from clay soils at the field and watershed scale can prevent catastrophic events, such as flooding and could provide early warning and save lives and property. Besides agricultural and environmental applications the project also provides new insights for geotechnical engineering. Structural damage to buildings and roads due to active clay soils is an important
economic factor. Improved predictions of swelling behavior could prevent such damages and save millions of dollars every year. Another potential application is the development of design criteria for clay liners used to seal waste repositories to prevent leaching and migration of toxic contaminants to aquifers and other water resources.
Publications
- Or, D. and Tuller, M. 2003. Reply to comment on 'Cavitation during desaturation of porous media under tension' by Toker, N.K., J.T. Germaine, and P.J. Culligan. Water Resour. Res., 39(11):1306.
- Or, D. and Tuller, M. 2003. Hydraulic conductivity of unsaturated fractured porous media: Flow in a cross-section. Advances in Water Resources, 26(8):883-898.
- Steinberg, S.L., Jones, S.B., Or, D., Daidzic, N.E., Tuller, M. and Ogden, F. 2003. Tensiometer measurements under variable gravity conditions, SSSA Annual Meeting Abstracts, November 2-6, Denver, Colorado.
- Jones, S.B., Or, D., Tuller, M., Steinberg, S., Humphries, S.D., Bingham, G.E., Daidzic, N.E. and Reddi, L.N. 2003. Influence of Variable Gravity on Liquid Configurations in Micromodels, SSSA Annual Meeting Abstracts, November 2-6, Denver, Colorado.
- Tuller, M., Gebrehawariat, K., Or, D. and Muhunthan, B. 2003. Experimental Studies on Swelling and Saturated Flow Behavior of Clay Soils. SSSA Annual Meeting Abstracts, November 2-6, Denver, Colorado.
- Steinberg, S.L., Alexander, J.I.D., Daidzic, N., Jones, S., Kluitenberg, G., Or, D., Reddi, L. and Tuller, M. 2003. Flow and Distribution of Fluid Phases through Porous Plant Growth Media in Microgravity. Bioastronautics Investigator's Workshop. Abstract Volume p. 121. Jan. 13-15, Galveston, Texas.
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