The Calibration of the Richards Flow Equation for a Draining Column by Parameter Identification

Before the Richards equation can be used to simulate the flow of moisture through a soil it is necessary to estimate the water capacity and hydraulic conductivity functions which appear as coefficients. We present four parameter identification methods and one direct method for estimating these hydraulic properties. For the sample problem considered, the parameter identification method which used cumulative discharge data to estimate water capacity and hydraulic conductivity performed the best in predicting water content as a function of depth and time during drainage.