The construction of new barrages increases the levels of groundwater, which affects the foundations of structures and agricultural land in those areas. It was therefore necessary to study the effect of the construction of New Assiut Barrage on increasing the levels of groundwater in the city of Assiut. New Assiut Barrage (NAB) is located in the city of Assiut, which was constructed about 400 meters north of the location of Old Assiut Barrage. It is expected that after the operation, an increase in surface water levels will occur in the upstream of barrage (next to the Al-Walidiyah district) and an increase in surface water levels in the downstream along the northern bank of Assiut city.  All this in turn increases the levels of groundwater and also submerges part of the northern bank of city. This study is based on Finite Difference method (FDM) and Geographical Information Systems (GIS) to produce two types of layers. The first layer has the values of groundwater levels for the entire study area, the second layer is a map of the terrain of the earth. Through the analysis of the two layers, can be determined the places of appearance of groundwater above the surface of the earth, and the amount of immersion in the northern banks.