Fluvial geomorphology of the Middle Reach of the Huai River

The Middle Reach of the Huai River (MRHR) flows northeast into the Hongzehu Lake. Before entering the Hongzehu Lake, the Huai River has a braided channel which is shallow and wide, and the riverbed has a negative slope. Based on the characteristics of the MRHR, this river reach can be divided into the following sections: a quasi-straight (or mildly curved) section, a bend section, and a braided section. The majority of the MRHR is quasi-straight. In this paper, several parameters are used to assess the geomorphology of the MRHR. Statistical analyses are performed to establish a relationship between the span length ““L”” and channel width ““B”” for different channel patterns. The relationship between the meandering length ““S”” and bankfull channel width ““B”” is also derived. Results indicate that the bankfull channel width ““B””, the bankfull cross sectional area ““A”” and the average flow depth ““H”” are mainly dependent on the dominant discharge in the channel. A relationship is derived that describes the dependency of the curvature radius ““R”” on the dominant discharge ““Q””, water surface slope ““J”” and the turning angle ““α””.