Leaf water content and plant moisture stress, or plant water potential and their relationship with the floods and underground water were determined at different times during the day for tree species such as Faiherbia albida, Acacia erioloba, Tamarix usneioudes, euclea pseudebenus and salvadora persica, which are the most dominant tree species in the Lower Kuiseb River near Gobabeb where the study was done. PMS or plant moisture stress measures the demand for water within a plant and water content tells us how much water a plant hold in its tissue. PMS is measured in Bars and water content in percentage, the average maximum PMS measurements were recorded at mid day with Salvadora percica going up to 37 bar, the lowest PMS was recorded before dawn at 18:00 and in the morning at 06:00. Keywords: Namibia, Namib Desert, Kuiseb River, riverine vegetation, river basin management, Acacia erioloba, Faidherbia albida, Euclea pseudobenus, Tamarix usneoides, moisture, water stress.