Today's human society on the development and utilization of water resources are divided into two categories
but the need for rivers, lakes, estuaries to maintain a certain water level, Water quality.
aquatic products and water recreation, to maintain ecological balance, this use does not need to lead water from the water,
The other is the use of water (hydroelectric power), the development of water transport,
One is the amount of water required to remove the water from the water to meet the needs of people's lives and industrial and agricultural production, the number of consumption, quality has changed, in another place to return to water.
