A study was conducted in the semi-arid and arid region located in the northeastern part of Basra Governorate, southern Iraq, with the aim of employing geomatics techniques and mathematical modelling to build and develop a hydrological model for studying water balance in the study area and the volume of water supply from the Shatt Al-Arab river towards adjacent areas and its impact by soil salinity and Shatt Al-Arab river water during July 2022. The results indicated a decrease in water supply (WS) values in the soil profile with increasing distance from Shatt Al-Arab or from the tributaries and other water sources. At a distance of 300 meters from the water source, the highest WS values were recorded, amounting to 684.41 m3, significantly higher than other distances. This was followed by the distance of 600 meters with 580.76 m3, then 1200 meters with 515.45 m3, and finally, the distance of 2400 meters recorded the lowest values at 424.33 m3. The magnitude of decrease in WS values increased at high rates with increasing distance from Shatt Al-Arab towards remote barren areas with a significant correlation coefficient (r =0.73).