MODELING OF FURROW IRRIGATION - ADVANCE WITH 2-DIMENSIONAL INFILTRATION

A complete hydrodynamic furrow irrigation model (TRIDISUL) with two-di mensional infiltration is presented and applied to blocked furrows. Ri chards' equation in its two-dimensional form is used to quantify the i nfiltrated volume in all sections along the furrow. To this equation a n implicit method is used and the system of equations is solved with t he Gauss-Seidel method. Saint Venant equations are solved using the Ne wton-Raphson method and the double sweep algorithm. This model allows the simulation of the interactions between the height of the water abo ve the furrow bed and soil water movement during the advance, supply, recession and redistribution phases, It can give information on the po sition of the wetting front in the soil through time, allowing the qua ntification of the water stored in the root zone. It is therefore poss ible to choose the best inflow discharge, spacing between furrows and furrow shape to obtain the best irrigation efficiency,