Assessing water consumption and aquifer discharge through springs based on the joint use of rain and flow data in the Yarmouk River Basin

The method is proposed for assessing water consumption in the transboundary basin under the scarce available data on exploitation of water resources. The method is based on analysis of the dynamic rain–flow relationship which confirms the consistent flow decline during subsequent sub-periods as a result of the increased water consumption. The proposed method was applied to the Yarmouk River Basin up to the Maqaren Station. The study area (6058 km²) includes Syrian (more 80%) and Jordanian territories. The present study provided complete information on consumption from the Yarmouk River in Syria (1971–2009) and confirmed its significant impact on flow reaching Jordan (downstream area) and on aquifer discharge through springs. During 1997–2009 the total water consumption was estimated as 76% of the Yarmouk Natural Flow vs. 24% for the measured flow at Maqaren Station. Similar estimates for surface water and for groundwater are 82% and 67% vs. 18% and 23%, respectively. In 2006–2009, annual consumption (total, SW and GW) critically increased and reached to 95–100% of the Natural Flow. The perennial base flow of the Yarmouk River at Maqaren Station is caused by outflow of springs in the outlet section of the Hreer tributary, which represents the local aquifer discharge. Its mean annual value was assessed as 120 MCM (40% of the Yarmouk natural flow) but it decreased to almost complete dry-out in 2006–2009 under conditions of the decline in the water level of the basin aquifer and the depletion and drying of the springs as the result of the unrestrained increased pumping of groundwater. These results are useful for water balance estimation as well as for assessment and management of the water resources in Syria and Jordan. The method can be adapted to real-time monitoring of the water consumption from the Yarmouk River (Syria). The proposed method can be applied to other areas with problems of the transboundary water relations under scarce water resources and limited data on the water use.