常言道:人可三日无粮,不可一日无水。水是人们日常生活中须臾不可缺少的东西,水是生命的源泉,工业的血液、国民经济的命脉,水是任何物质也不可代替的有限的宝贵资源。我国水旱灾害相当频繁,水资源量按人均计算只有世界人均水平的四分之一,且时空分布极不均衡,南方多,北方少。北 As the saying goes, people can eat without food for three days and they can’t be waterless. Water is an indispensable element in people’s daily lives. Water is the source of life, the blood of industry, and the lifeline of the national economy. Water is a limited precious resource that cannot be replaced by any material. Floods and droughts in China are quite frequent. The amount of water resources is only one fourth of the world average per capita, and the distribution of time and space is extremely uneven. There are many in the south and less in the north. north