2013 Annual Report
The project is organized around short term and long term objectives. Looking to the near term (Objective 1), we will evaluate and adapt existing modeling strategies for incorporating vadose zone processes into regional simulations, identify parsimonious modeling techniques, assess uncertainties associated with differing modeling approaches, and make calculations illustrating uncertainties associated with modeling various management scenarios.
In the longer term, we anticipate that increased computing power and improved sensing technologies and land use data will eventually permit significantly higher resolution simulations than is currently possible. Toward that end (Objective 2), we will investigate the use of remote sensing and other data to estimate soil properties at a higher resolution, and will develop improved models for coupled overland and subsurface transport which will be able take advantage of high resolution topographic data.
The project should lead to recommendations for developing modeling components of basin-scale salinity and nutrient management plans, and to improved capabilities for predicting the long-term effects of management decisions on soil and groundwater quality. Replacing 5310-61000-014-00D 02/2012.
A critical SY vacancy has delayed progress on Objective 2.1. The vacant position has been filled recently, with a new scientist joining the research team in August of 2013.
Objective 2.2 of the project focuses on the development of new technologies for improved modeling of coupled overland and subsurface flow and transport. In FY2013 numerical and analytical models have been developed to simulate transport in runoff water, streams, and rivers. In particular, we have incorporated 1D and 2D formulations for overland flow and transport into a partial differential equation solver. Preliminary results have demonstrated the ability to accurately couple overland flow and transport with the subsurface. This model will be further refined and tested, before conducting detailed numerical experiments and examining upscaling issues. Existing analytical models have also been adapted to simulate transport in rivers. These models were based on 1D, 2D, and 3D solutions of the advective-dispersion equation (ADE), or the ADE with terms for transient storage and inactivation.
Perez Guerrero, J.S., Pimentel, L.C., Skaggs, T.H. 2012. Analytical solution for the advection-dispersion transport equation in layered media. International Journal of Heat and Mass Transfer. 56:274-282.
Siyal, A.A., Van Genuchten, M.T., Skaggs, T.H. 2013. Solute transport in a loamy soil under subsurface porous clay pipe irrigation. Agricultural Water Management. 121(2013):73-80.
Skaggs, T.H., Suarez, D.L., Goldberg, S.R. 2013. Effects of soil hydraulic and transport parameter uncertainty on predictions of solute transport in large lysimeters. Vadose Zone Journal. doi:10.2136/vzj2012.0143.
Perez-Guerrero, J.S., Pontedeiro, E.M., Van Genuchten, M.T., Skaggs, T.H. 2013. Analytical solutions of the one-dimensional advection-dispersion solute transport equation subject to time-dependent boundary conditions. Chemical Engineering Journal. 221:487-491.
Kasel, D., Bradford, S.A., Simunek, J., Putz, T., Vereecken, H., Klumpp, E. 2013. Limited transport of functionalized multi-walled carbon nanotubes in two natural soils. Environmental Pollution. 180:152-158.
Leij, F.J., Bradford, S.A. 2013. Colloid transport in dual-permeability media. Journal of Contaminant Hydrology. 150:65-76.
Simunek, J., Jacques, D., Langergraber, G., Bradford, S.A., Sejna, M., Van Genuchten, M.T. 2013. Numerical modeling of contaminant transport using HYDRUS and its specialized modules. Journal of Indian Institute of Sciences. 93(2):265-284.
Van Genuchten, M.T., Leij, F.J., Skaggs, T.H., Toride, N., Bradford, S.A., Pontedeiro, E.M. 2013. Exact analytical solutions for contaminant transport in rivers 1. The equilibrium advection-dispersion equation. Journal of Hydrology and Hydromechanics. 61(2):146-160.
Kasel, D., Bradford, S.A., Simunek, J., Heggen, M., Vereecken, H., Klumpp, E. 2013. Transport and retention of multi-walled carbon nanotubes in saturated porous media: Effects of input concentration and grain size. Water Research. 47(2):933-944.
Liang, Y., Bradford, S.A., Simunek, J., Vereecken, H., Klumpp, E. 2013. Sensitivity of the transport and retention of stabilized silver nanoparticles to physicochemical factors. Water Research. 47(7):2572-2582.