comparison of wedernikow theoretical method with ingham empirical method in estimation of seepage from earth channels in roodasht region of isfahan

estimation of seepage from water channels are necessary in evaluating water productivity in agricultural sector as affected by floodwater spreading on plains and artificial recharge of groundwater. several empirical seepage equations have been developed for this purpose. previous research results in iran have shown lots of variation in the coefficients and the empirical equations change in different areas and regions. it appears that locally calibrated theoretical equations could give satisfactory results for different conditions. for this purpose, actual measured seepage from earth channels (in the roodasht region in isfahan province) and ingham empirical equation were used and compared with wedernikow theoretical method. differences between the measured values and estimated values of seepage in july and august were compared using rrmse and mae statistical indexes. the results showed that the average rrmse and mae statistics were 0.275 and 0.01 for the ingham method. but, these values were 0.145 and 0.005 for wedernikow theoretical method. these indexes showed that wedernikow theoretical equation gave the best result of seepage estimated values compared with empirical equations in roodasht region channels. moreover, the other advantage of the theoretical equation is that it can be developed and extended to various areas.