Fresh water is naturally occurring water on the Earth ‘s surface in ice sheets, ice caps, glaciers, ponds, lakes, rivers and streams, and underground as groundwater and underground streams.
Fresh water is generally characterized by having low concentrations of dissolved salts and other total dissolved solids. The term specifically excludes seawater and brackish water. A human body can survive 8-14 days without water depending on the person. First of all our very existence will be in danger in the absence of fresh drinking water. Besides we will not get the much needed source of irrigation for our fields and as a result there could be lot of scarcity of food.
So we will face a situation of food crisis. Water running in rivers is tapped and big dams are constructed and hydropower is produced. Moreover river transport system is not possible in case water stop flowing in rivers. Although plenty of water is available in oceans but that is not fit to be consumed by human beings as it is salty.