ABSTRACT In this paper, the geochemical modeling code NETPATH is used to calculate net geochemical mass - balance transfer of selected minerals and also to evaluate the main geochemical processes that take place in the system. The modeling results show that mixing occurs in the system by ratios vary widely between I % and 93% of the sampled wells. Calcite and dolomite dissolution occurs in 50% and 40% of the investigated groundwater samples, respectively, while undersaturation state of gypsum, anhydrite and silica in almost all groundwater samples and surface water of Lake Nasser is remarkable. Both the hypothetical salt assemblages and hydrochemical profiles show that there is seepage from Lake Nasser to the groundwater of the Nubian aquifer. Also the hydrochemical profiles determined the distance to which the seepage occurred. On the other hand, cluster analysis reveals a random spatial distribution of the different chemical components. Moreover, the distance to which the mixing process between Lake Nasser water and the Nubian aquifer groundwater was found to be 50-60 krn from the Lake's borders.