American Society of Civil Engineers


Sustainable Root Zone Salinity and Shallow Water Table in the Context of Land Retirement


by Purnendu N. Singh, (Postdoctoral Scholar, Dept. of Land, Air and Water Resources, Univ. of California, Davis, CA 95616. E-mail: pnsingh@ucdavis.edu), Wesley W. Wallender, (corresponding author), M.ASCE, (Professor, Dept. of Land, Air and Water Resources and Dept. of Biological and Agricultural Engineering, Univ. of California, Davis, CA 95616 E-mail: wwwallender@ucdavis.edu), Marco P. Maneta, (Dept. of Geosciences, Univ. of Montana, Missoula, MT 59812; formerly, Postdoctoral Scholar, Dept. of Land, Air and Water Resources, Univ. of California, Davis, CA 95616), Stephen L. Lee, (Program Manager, Interagency Land Retirement Team, Bureau of Reclamation, U.S. Department of the Interior, 1243 N. St., Fresno, CA 93721), and Beatrice A. Olsen, (Interagency Land Retirement Team, U.S. Fish and Wildlife Services, 1243 N. St., Fresno, CA 93721)

Journal of Irrigation and Drainage Engineering, Vol. 136, No. 5, May 2010, pp. 289-299, (doi:  http://dx.doi.org/10.1061/(ASCE)IR.1943-4774.0000065)

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Document type: Journal Paper
Abstract: This study uses five years of field data from the Land Retirement Demonstration Project located in western Fresno County of California to develop a comprehensive theoretical and numerical modeling framework to evaluate the specific site conditions required for a sustainable land retirement outcome based on natural drainage. Using field data, principles of mass balance in a control volume, the HYDRUS-1D software package for simulating one-dimensional movement of water, heat, and multiple solutes in variably-saturated media, and a model-independent parameter optimizer, the processes of soil water and solute movement in root zone and deep vadose zone were investigated. The optimization of unsaturated soil hydraulic parameters and downward flux (natural drainage) from the control volume against observed vadose zone salinity levels and shallow groundwater levels yield difficult to obtain natural drainage rate as a function of water table height within the control volume. The results show that the unsaturated soil hydraulic properties and the downward flux from the soil profile are the critical parameters. A "natural drainage approach" to sustainable land management for drainage-impaired land is proposed. With this approach it is feasible to design a sustainable land use regimen for drainage-impaired lands in general and retired lands in particular.


ASCE Subject Headings:
Irrigation
Land management
Leaching
Salt
Drainage
Salinity
California
Water table

Author Keywords:
Irrigation
Land management
Leaching
Salt balance
Drainage