Flexi Says: Human activities impact the water cycle in a number of ways. Large areas of paved surfaces prevent percolation of water into the ground. This increases runoff across surfaces, which can lead to urban flooding. Large paved areas also reduce the amount of water reaching aquifers, leading to slower groundwater recharge. Human water consumption further depletes groundwater and surface water reservoirs as well. Dams alter the flow of rivers. Global warming changes large-scale patterns of flow among reservoirs by increasing evaporation and transpiration, and by altering precipitation patterns in ways that can produce drought in some areas and flooding in others.
