Synthesis of rating curves from local stage and remote discharge monitoring using nonlinear muskingum routing

Abstract

The specification of environmental water requirements in rivers requires the ability to relate discharge to local hydraulic conditions. Rating curves at locations of interest are a basic requirement, but are difficult and time-consuming to compile using conventional methods. River stage can be monitored relatively easily and can be related to discharge monitored at a different location on the same river by flood routing techniques. Simultaneous short-term records of local stage and remote discharge can be used through a nonlinear Muskingum model to optimize the parameters of a rating function at the local site. The approach is verified by resynthesizing a rating function used in rigorous routing in a hypothetical channel, and applied to a monitored site on the Sabie River in South Africa, with account taken of dynamic bank storage.