Water covers 2/3 of the earth surface, but it is mainly available as saline water (approximately 97%). The reaming amount is partially locked up in ice and glaciers, while the total annual precipitation on earth’s surface (approximately 108,000 km3) is divided in green water, total volume evaporated and transpired that is about 61,000 km3, and blue water, total volume of water flowing in the river systems 47,000 km3. Given the strong temporal fluctuations of the stream flow, only a portion of the blue water (a value between 9,000 km3 and 14,000 km3) can be ultimately controlled. At the present, we are already using 1/3 (about 3,400 km3) of the total amount of controllable water.
How to cite: Manfreda, S., The Water Management in the Present Century, Hydrology Current Research, 4:1 (doi: 10.4172/2157-7587.1000e105), 2013. [pdf]