Discharge Response in a Water Conveyance System

Abstract

The operation of discharge and response delay in an open channel irrigation system are discussed using mathematical analyses and experimental evaluations. Analytical treatments are made based on the linearized diffusion analog model.
It was clarified that the dimensionless distance and time obtained as a result of the analyses were useful in describing the operation response. Also, the phenomena of the response to the operations were transferred downstream as dynamic, dynamic-kinematic and kinematic waves according to the dimensionless factors.
The approximated equations for predicting the response were derived from a linearized diffusion analog model within the effective range of distance. The validity of this approximation was confirmed by experimental evaluations.
The waves in an open channel regarded as the first delay system is discussed. The equations for evaluating the parameters of the first delay system were derived from the aforementioned approximation and the condition of continuity. The validity of using the first delay system was confirmed by computer simulations. Inversely, gate control corresponding to the desired response at the irrigation field is discussed using the first delay system.