SBIR-STTR Award

The relationship among water potential, hydraulic conductivity, and water content eLK-e) are some of the most commonly sought soil physical properties. Prediction of water and solute movement in both agricultural and environmental situations is ultimately predicated upon an adequate experimental description of porous media. A rapid and accurate method to determine these relationships would find wide application in agricultural, environmental, and engineering applications. Because much of the water and solute flow information sought typically occurs within the expected ral ge of our proposed one-step pressure cell (0 to I bar), a large portion of the necessary hydraulic information potentially can be obtained with one automated measurement. We propose to test and refine a working prototype one-step inflow/outflow cell to obtain data to estimatet-K-o. The design is essentially a modified Tempe cell equipped with a surface tensiometer, porous nylon membranes, and pressure transducers to automate data collection. In order to prove the concept, we must also test the feasibility of analyzing this new information. The parameters obtained must be compared to other methods. Data analysis will include diffusivitytconductivity estimates using several methods available in the literature. These are discussed in more detail in the proposal.Applications:Ground-water pollution is a critical national environmental issue. Increasing pressures and demands on soil and water resources have resulted in interest from researchers, consultants, and regulators in methods to accurately predict water and chemical movement. Because of the large amount of time involved and expense of laboratory work, many tests used to make remedial decisions are not well replicated. Availability of fast, yet accurate, methods of testing would lead to a stronger base of information for monitoring and remedial work and also increase the number of samples and variables that could be tested in research programs.

The relationships among water potential, hydraulic conductivity, and water content (t-K-8) are some of the most important and commonly sought soil physical properties in agricultural, environmental, and engineering applications. These applications generally center around water and contaminant transport. Predication of water and solute movement in these applications is ultimately predicated upon adequate experimental data. Current methods of obtaining this information are time- consuming, expensive, and often yield inaccurate parameter estimates. Therefore, in Phase I, we designed, built, and performed preliminary testing on a one-step cell to achieve the following objectives: 1) rapid experimental results, 2) improved experimental precision, 3) reduced labor for experimentation and analysis, and 4) improved accuracy in parameter estimates. The one-step device consists of an innovative cell design coupled with a datalogger. Data acquisition is event controlled. The system automatically starts and stops the experiment. Time, outflow, and surface potential are recorded at user-specified weight-change increments. I Based upon the encouraging Phase I results, we propose to develop, construct, distribute, and test a one-step outflow system in conjunction with collaborating specialists. The final product will be a practical flexible tool for commercial and research applications.

Anticipated Results:
Groundwater pollution is a critical national environmental issue. Increasing pressures and demands on soil and water resources have resulted in interest from researches, consultants, and regulators in methods to accurately predict water and chemical movement. A consensus exists that the quantity and quality of information used to make projections and decisions needs improvement. Current methods of obtaining soil hydraulic properties are slow, labor intensive, and subject to criticism. Development of improved methods for determination of soil hydraulic properties will improve decision-making in the environmental industry and provide a cost-effective research tool.