水与国民經济各部門都有密切的关系,无論灌溉、发电、航运、工厂、矿山、城市供水等都需要水和利用水。要充分利用天然河川的水利資源,消灭水旱灾害,就需要制訂全面治理开发河流的流域規划,并修建必要的水利工程。要制訂流域規划和修筑水利工程,就首先需要了解天然河川的水文特性。如果, Water and all sectors of the national economy are closely related, regardless of irrigation, power generation, shipping, factories, mines, urban water supply and the need for water and water. To make full use of the water resources of natural rivers and eliminate floods and droughts, it is necessary to formulate river basin plans for comprehensively harnessing and developing rivers and to construct necessary water conservancy projects. To draw up river basin planning and construction of water conservancy projects, we must first understand the hydrological characteristics of natural rivers. in case,