It is common knowledge that Yarmouk River Basin (YRB) is shared between Jordan and Syria. Management of YRB trans-boundary water resources is attracting increasing interest because it is a strategic water resource for the riparian countries. Actually, lack of sharing information regarding hydrological flows and basin\'s water management between partners\' countries makes it difficult to distinguish between natural and man-made factors affecting the water body. Therefore, this study seeks to address and assess the main on-site changes that exert on YRB. Geospatial technique and arithmetic equations were combined to carry out an assessment of the changes on water resources in YRB. Data, information and field measurements of the basin were aggregated, compiled and presented to determine the extent of changes during the period 1980–2020. Remarkable findings showed that precipitation amount in the basin significantly declined during the period 1980–2020 in particularly after the year 1992. Pumping rate of groundwater was 550×103 m3/a, exceeding the basin\'s safe yield. Draw down of static groundwater level over time approached the value of –3.2 m/a due to the over abstraction in the aquifer body. Additionally, the evaporation rate reached more than 99％ in some regions in the basin. Moreover, the number of private wells has increased from 98 wells in 1980 to 126 wells in 2020, showing the excessive extraction of groundwater. These findings indicate that the study area is subjected to a considerable groundwater depletion in the near future due to extensive abstraction, continuous drilling of illegal wells and decreased annual precipitation under the shadow of the rapid population growth and continuous influx of refugees. Therefore, decision makers-informed scenarios are suggested in the development of water resource portfolios, which involves the combination of management and infrastructural actions that enhance the water productivity of the basin. Further studies are recommended to evaluate the on-site changes on water resources in YRB in collaboration with riparian countries and to establish monitoring system for continuous and accurate measurements of the basin.