culculation of scs infiltration equation by least-squares method

soil conservation service (scs) adjusted the kostiakovs infiltration model by adding a constant coefficient, for improvement of estimation. the improved model has three constant parameters, which are difficult to calculate. so scs has taken the third constant parameter as equal to 0.65-0.7 cm to simplify the estimation. this parameter varies in different soil and often outranges the scs estimation. in this study the estimation of model parameters have been achieved by the combination of least-squares and newton-rophson numerical method. for four types of soils the infiltration parameters were calculated. comparisons of the results of scs and this study have shown that, the model with parameter estimated by the new method has better agreement with field measurement than the scs method.