Determination of the groundwater recharge in the Blagoevgrad valley Neogene sediments

A comprehensive approach to determine the natural groundwater recharge in the Blagoevgrad valley Neogene sediments is presented. It involves the application of various methods such as the balance method, hydrodynamic modeling in GIS, the FeFlow numerical model, the Döll et al. empirical method. The obtained results show good similarity between different methods, including the long-term groundwater recharge for the study area calculated by rainfall infiltration. Therefore, the complex approach used gives an accurate estimate of the groundwater recharge in the Blagoevgrad valley associated with Neogene sediments. It can be successfully applied to determine the natural groundwater resources for other similar groundwater bodies. In this way, the groundwater resource assessments, management and conservation in Bulgaria can be significantly improved.