长江流域水系连通特征及其影响因素分析

Drainage connectivity characteristics and influential factors of Yangtze River Basin

水系的连通性是河流健康评价的一个重要指标，它影响到河道生态需水量、通航水深、湿地保留率等。在健康长江评价体系的14个指标中，水系的连通性作为一个重要指标被首次提出。通过对水系连通性基本概念的探讨，归纳了长江水系连通的基本类型，包括河流与河流连通、河流纵向连通和河湖连通3类；分析了长江流域水系连通基本特征和影响水系连通的原因。从地质历史时期及人类历史时期的时间尺度看，新构造运动、气候变化等自然因素在水系连通的阻碍方面是主导因子，但从100～10a和年时间尺度上看，特别是近百年来，人类活动对水系的连通在很多地方起着决定性的作用。

As an important index for assessing river health, drainage connectivity may affect ecological water requirement of river channel, water depth for navigation and wetland conservation ratio, etc. It is put forward for the first time as one of 14 indices of the Yangtze River health assessment system. We discussed the concept and category of the drainage connectivity and ana- lyzed its characteristics and influential factors. The drainage connectivity includes three types： river to river connection, longitudinal river connection and river to lake connection. The same factor has different effects on the drainage connectivity for different time scales. For the geological time scale, neo - tectonic movement and climate change are the main factors influencing the drainage connectivity; and for 100 -10 years and annual time scale, especially for the recent 100 years, human activity is the most important influential factor.