水系的发育及其分布组合直接影响着干流水情动态,并在很大程度上控制着流域的地貌发育。在构造活动区,水系常沿构造带发育,形成独特的水系特征和河谷形态。研究水系发育和河谷成因以及河谷地貌特征,可为水能利用和河道整治提供科学资料和依据。曹娥江流域主要位于浙东绍兴地区,处于四明山、天台山与会嵇山之间,形成一个完整的流域盆地。

The origin of the drainage system and geomorphical development of the Cao-e River was brought under control by geologic structures,especially by faults of new tectonic movements.The original three great tributaries of the Cao-e River have become drainage divisions due to the influence of new tectonic movements,and Pleistocene stream deposits have been left over the drainage divisions.But for each former tributary,two new parallel rivers flowing in the same direction,at a short distance adjacent to each other,with symmetric tributaries,have developed along both sides of the elevated block formed by these deposits:the Xinchang River and the Huangze River,the Chengtan River and the Zuoyu River,and the Changle River and the Xiaowu River,respectively.The Yanshan eruptive rock and its north-eastern strike folds formed the foundation of modern low height mountains.Cretaceous andstone,gravel beds and eruptive rock deposited in structure basins made up the foundation of modernlow mountains and hils.Basaltic table-land that formed at the end of the Tertiary period to the beginning of the Quaternary period was cut apart into high,middle and low basaltic table-land due to unequal height of formation.Therefore,the revived faults due to new tectonic movements became clear geomorphic demarcation lines,new rivers developed along those demarcation lines,and the original river system changed into the present river system.