Recession Flow in Surface Irrigation

The recession flow of surface irrigation, furrow or border, can be expressed as a simple power function which is derived by assuming a linear storage of recession flow. The recession flow length is expressed as a function of recession time and a recession constant. The knowledge of the length of recession flow profile and recession time is important in the evaluation of irrigation efficiency, especially in the border irrigation which has a relatively large volume of surface storage at the time when the inflow is shut off. Laboratory experiments were conducted and field data of sugarcane furrow experiments were applied to check the validity of the derived mathematical models of recession flow. A simple recession flow equation is also derived by considering the recession flow as depleting water from a single shallow linear reservoir. For a relatively short length and small slope of furrow or border, the simple recession flow equation seems to be applicable.