American Society of Civil Engineers


Coupled Surface-Subsurface Solute Transport Model for Irrigation Borders and Basins. II. Model Evaluation


by D. Zerihun, (Asst. Res. Scientist, Dept. of Soil, Water, and Envir. Sciences, 429 Shantz Bldg. No. 38, Univ. of Arizona, 1200 E. Campus Dr., Tucson, AZ 85721), C. A. Sanchez, (Prof., Dept. of Soil, Water, and Envir. Sciences and Dir., Yuma Agric. Ctr., Univ. of Arizona, W. 8th St., 6425 Yuma, AZ 85364), A. Furman, (Inst. of Soil, Water, and Envir. Sciences, ARO-Volcani Ctr., P.O. Box 6, Bet Dagan 50250, Israel; formerly, Res. Assoc., Dept. of Hydro. and Water Resour., Harshbarger Bldg. No. 11, Univ. of Arizona, Tucson, AZ 85721), and A. W. Warrick, (corresponding author), (Prof., Dept. of Soil, Water, and Envir. Sciences, 429 Shantz Bldg. No. 38, Univ. of Arizona, 1200 E. Campus Dr., Tucson, AZ 85721 E-mail: aww@ag.arizona.edu)

Journal of Irrigation and Drainage Engineering, Vol. 131, No. 5, September/October 2005, pp. 407-419, (doi:  http://dx.doi.org/10.1061/(ASCE)0733-9437(2005)131:5(407))

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Document type: Journal Paper
Abstract: The development of a coupled surface–subsurface solute transport model for surface fertigation management is presented in a companion paper (Part I). This paper discusses an evaluation of the coupled model. The numerical solution for pure advection of solute in the surface stream was evaluated using test problems with steep concentration gradients. The result shows that the model can simulate advection without numerical diffusion and oscillations, an important problem in the solution of the advection–dispersion equation in advection dominated solute transport. In addition, a close match was obtained between the numerical solution of the one-dimensional advection–dispersion equation and a simplified analytical solution. A comparison of field data and model output show that the overall mean relative residual between field observed and model predicted solute breakthrough curves in the surface stream is 16.0%. Excluding only two outlier (in the graded basin data) reduces the over all mean relative residual between field observed and model predicted breakthrough curves to 5.2%. Finally, potential applications of the model in surface fertigation and salinity management are highlighted.


ASCE Subject Headings:
Surface irrigation
Coupling
Models
Unsaturated flow
Solutes
Salinity