Determination of MODFLOW model sensitivity toward distribution coefficient (Kd)

One of the important effectives that recently lionizes in Environmental Geotechnics, is"distribution Coefficient (Kd)". The range of this parameter is very wide, ranging as much as "0" to"1000" and more. This wide range is important in using numerical models for underground water andcontaminant transformation modeling. MODFLOW is one of the appropriate models in undergroundwater and contaminant transformation modeling.It is very important to understand the sensitivity of this model towards Kd and the effects ofselected method in modeling given the necessity of this model to distribution Coefficient and itsability about calculation of Kd in 3 methods.This research has been performed for the soil of Rey zone with MTBE and all of the tests have beenperformed according to ASTM standards.Finally it is concluded that the sensitivity of MODFLOW toward value of Kd and itscalculation method is inconsiderable and the model is most appropriate when Kd is not known.