水是人类发展不可缺少的自然资源，是人类和一切生物赖以生存的物质基础。当今世界，水资源不足和污染构成的水源危机已成为任何一个国家在政策、经济和技术上所面临的复杂问题和社会经济发展的主要制约因素。
Water is an indispensable natural resource for human development and the material foundation on which humans and all living organisms rely for survival. In today's world, the water crisis caused by insufficient water resources and pollution has become a complex problem faced by any country in terms of policy, economy, and technology, as well as a major constraint on socio-economic development.
在水资源日益缺乏的情况下，水资源污染的现实又使人们增加了一份忧虑。在中国很多地区，由于各种复杂因素致使不少水体已经严重受到污染，这更加剧了水资源紧缺的矛盾。
In the context of increasingly scarce water resources, the reality of water pollution has added to people's concerns. In many regions of China, due to various complex factors, many water bodies have been severely polluted, which further exacerbates the contradiction of water resource scarcity.
当今人类社会对水资源的开发利用分为两大类：
The development and utilization of water resources in today's human society can be divided into two categories:
一类是从水资源取走所需的水量，满足人民生活和工农业生产的需要后，数量有所消耗，质量有所变化，在另外地点回归水源。
One type is to extract the required amount of water from water resources, meet the needs of people's daily life and industrial and agricultural production, consume the quantity and change the quality, and return to the water source at another location.
另一类是取用水能（水力发电）、发展水运、水产和水上游乐，维持生态平衡等，这种利用不需要从水源引走水量，但是需要河流、湖泊、河口保持一定的水位、流量和水质。
Another type is the utilization of water energy (hydroelectric power generation), the development of water transportation, aquaculture and water recreation, and the maintenance of ecological balance. This utilization does not require the diversion of water from water sources, but requires rivers, lakes, and estuaries to maintain a certain level, flow rate, and water quality.