In the frame of the Omani – German APPM pilot project, a tailor made integrated water resources management (IWRM) for the Barka Area in the South Batinah Region (Sultanate of Oman) is being developed. The quantification of the current rate of groundwater recharge is a prerequisite for an efficient and sustainable groundwater management. Based on an outline of the major recharge pathways in the study area, this paper focuses on approaches for assessment of groundwater recharge to the alluvial aquifer on the Batinah coastal plain. Due to the specific geological conditions, recharge areas can not be derived from surface catchment divides. Therefore, fuzzy approaches are used to describe the unknown extent of the recharge areas in the partly karstified mountain region. This approach allows for incorporation of qualitative knowledge from isotope studies into the estimation procedure. Estimates of long term mean annual recharge are presented. The results are compared to inverse estimates of groundwater recharge resulting from a steady state calibration of a 3D density dependent groundwater model.. Beyond, an outlook for a transient state application is given. Options to enhance the accuracy of recharge estimates are discussed.

In the frame of the Omani – German APPM pilot project, a tailor made integrated water resources management (IWRM) for the Barka Area in the South Batinah Region (Sultanate of Oman) is being developed. The quantification of the current rate of groundwater recharge is a prerequisite for an efficien...