Approach to Control the Depth of Water in Basin Irrigation and Wetland Flooding

Abstract

The controlled ponding of water over level terrain in basin irrigation or wetland flooding is described quantitatively as a three-phase process. During the first phase, water is applied at a known rate until ponding emerges at the time of ponding initiation. In the second phase, water continues to be applied at the same rate until a desired ponded depth is attained. In the third phase, water is applied to maintain the desired ponded depth during an arbitrarily long period. The desired ponded depth is maintained by adjusting the water-application rate to equal the infiltration rate plus the evaporation rate. The time of ponding, the ordinary differential equations (ODEs) governing cumulative infiltration during the second and third phases, and the water-application rate during the third phase are derived in this work using an extended Green-and-Ampt formulation of infiltration. Computational examples illustrate the solutions of the derived ODEs and their application in the control of basin irrigation and wetland flooding.