Water use efficiency for sedment transport in the lower Yellow River

摘要

A four-layer framework was advanced to study the Water Use Efficiency for Sediment Transport (WUEST). The major state parameters at different layers of the system include the incoming water and sediment from the upstream (IWS), the characteristics of river channel (CRC), the sediment carrying capacity of river flow (SCF), and the control capability of hydraulic engineering works (CEW). According to the measured data from 1950 to 1997, the WUEST in four typical reaches of the Lower Yellow River was investigated under different conditions (or IWS), i.e. the natural condition (NC), the engineering-controlled condition (EC), the complex condition (CC) and the abnormal conditions (AC). Comparison was made between different operation schemes in connection with sediment carrying capacity, e.g. the scheme, among others, of using the water in wet season to flush the total sediment load in the whole year. These schemes could decrease water demand for sediment transport and enhance the water use efficiency. The schemes could be implemented by the proper operation of hydraulic engineering works. In addition, thresholds of the water use for sediment transport (WUST) under different conditions were also proposed.