A simple and practical model balance system was developed to predict the advanced distance with time in level border irrigation systems, this model proposed the surface and subsurface water storage during irrigation as one unit with a single shape factor changed with advance time, the proposed shape factor was calculated at different time intervals by using 13 field test including all the involved with surface irrigation process. The obtained values of the shape factor in addition to the other

more »

... ariable was grouped in dimensionless terms, the shape factor was correlated with these terms by using (SPSS) statically analysis program. The proposed model was evaluated with afield data and compared with other models, the results shows good agreement between the field data and the proposed model, the study also conclude that that the advance affected significantly by manning roughness, flow rate and kostiakov coefficient in different degrees the analysis also show that the change in discharge have the largest effect on advance distance among the other variables.