APPLICABILITY OF LINEAR SYSTEM THEORY FOR SIMULATING FLOW TO TILE DRAIN

Abstract

This thesis is documented to test the one parameter linear system theory model to predict the subsurface tile-drain flow for a given hyetograph and soil characteristics. A parameter K (storage coefficient) has been estimated by trial and error for which the estimated tile drain hydrograph best matches with observed hydrograph. The model comparisons with the WQFS observed hydrographs were promising, the field station is located at the Agronomy Centre for Research and Education in West Lafayette, Indiana (USA). It was noticed that the selection of events favored those situations where the model was likely to be successful. In other words, by satisfying the mass balance criterion, there was some reassurance that the total volume of rainfall had infiltrated the soil and runoff was not generated. Further linear system theory model is justified by analyzing the flux movement by using the Richard's equation. The relation between total moisture content and flux at the lower boundary is linear for the initial condition: saturated moisture content, and upper boundary condition soil moisture content at all the times. Finally, it concluded that the simple linear system theory can predict the tile drain hydrographs for a given recharge, irrespective of subsurface zones