Discussion on ecological construction scheme for navigation recovery in the lower Yellow River

The key issues, such as sediment accumulation, wandering river regime and the obstruction of water-related projects, are of great significance of restricting the construction of ecological waterway in the lower Yellow River. After the analysis with measured data, calculation with mathematical model and comprehensive analysis, it is believed that the minimum back-full discharge in the lower Yellow River has already reached 4,300 m³/s, the water surface width corresponding to the minimum navigable volume has reached 120~200 m and water depth has reached 1.0~2.5 m since the operation of Xiaolangdi Reservoir. Along with the completion and combined application of water-sediment regulating system in the future, a middle-water-level river channel of about 4,000 m³/s will be maintained in a relatively long time, with a certain condition for navigations. It is proposed that with the operation of Guxian Reservoir and Dongzhuang Reservoir and the construction of ecological corridor in the lower Yellow River, an ecological waterway in compliance with Class Ⅳ waterway standard (Class Ⅲ at some sections) and with a length of about 800 km can be formed by virtue of ecological dredging works as a middle-water-level navigable river channel, through regulation of wandering river reaches and ecological reconstruction to remove navigation-hampering structures. It is suggested to promote and accelerate the construction of the ecological waterway in the lower Yellow River under the principles of “unified arrangement, step by step, dredging before navigation and gradual improvement”.