Predicting seepage from unlined earthen channels using the finite element method and multi variable nonlinear regression
Seepage losses from unlined channels are a major contributor to water loss in the agricultural sector. Quantification of seepage losses can improve water conveyance efficiency and provide solutions to water scarcity. In this study, a numerical simulation method is applied to investigate the factors that affect seepage from earthen channels. SEEP/W software was used to generate finite element method (FEM) solutions of the seepage flow equations. 246 numerical models, including different sections of trapezoidal, rectangular, and triangular earthen channels were studied using FEM. Numerical results are compared to available observation data from Zayandeh-Rud irrigation channels in Iran. Non-linear regression equations for the four empirical seepage equations are obtained from the SPSS statistical software. The results show that nonlinear multivariate regression relationships provide a suitable match for estimating seepage discharge. The accuracy of the suggested nonlinear regression equation in terms of R2 and RE are 0.928 and -2.42 %, respectively. Comparison of the seepage discharge with the empirical relationships showed that the empirical relationships have excessive error.