洞庭湖响水坎险滩的演变及成因分析

Analyses on origin and evolution of Xiangshuikan rapids in the Dongting Lake

应用遥感地质和水动力演变分析法,分析了洞庭湖响水坎滩险的成因.探讨了影响湖区跌坎形成的水文和地质因素、水动力学条件及跌坎上、下游河床演变情况.地层岩性与沉积厚度的突变、地质构造单元分布等,是响水坎形成原始河床跌坎的内在原因,原始跌坎是出现跌水的前提,河湖边界及水流动力作用是跌水存在的外在条件,河湖水文组合决定了响水坎滩段是否碍航.

The origin of Xiangshuikan rapids in the Dongting Lake is analyzed by using remote sensing geological and hydrodynamic methods. The effect factors of water steepfall in hydrology, geology and hydrodynamics, and the fluvial process upstream and downstream of the steepfall are discussed. It can be seen that the mutation of strata lithologic and sedimentation thickness, and the geologic structural unit distribution are the internal causes of the original bed falling-step formation. The precondition of the water fall is the original bed falling-step; the external conditions of the water fall are the lake boundaries and dynamic action of flow; and the combination of hydrological conditions decides whether the Xiangshuikan rapids obstructs navigation.