عنوان مقاله [English]
In hydrology studies, the river regimes are considered to be natural while this assumption is not correct since the river water is used for developing agriculture, industry, and other needs, particularly in the middle basins. The requirement for river base flow separation is to have access to natural river regime on a daily basis, which, regarding the limitations of naturalization, natural river regime can be calculated on an annual or monthly basis. Therefore, the estimation of base flow has been faced with some difficulties. On the other side, due to the complex relation of surface water with groundwater, the estimation of base flow is too hard. Therefore, in this study, the removal process method was used for naturalizing monthly discharge of Belbar basin, and Eckhart RDF algorithm was used since it takes aquifer characteristics into account for calculating base flow and it has the ability to optimize its parameters. The constant parameters of return and the maximum base flow index for monthly natural river discharge in hydrometric stations of Belbar dam were optimized. Then, the monthly base flow was calculated and the results showed that the monthly natural river discharge can be used like the daily natural river discharge with the same accuracy.