A finite element model to determine the effect of land-use changes on flood hydrographs

The finite element theory, in conjunction with Galerkin's residual method, was used to mathematically route overland and channel flow. This numerical procedure was applied to the kinematic equations of one-dimensional transient flow in open channels. A one-dimensional finite element scheme was used to simulate overland flow over the watershed and open channel flow in the main streams, after a finite element grid had been devised for both the watershed and the streams. Rainfall excess, the major input parameter, was obtained as a function of rainfall, depending on soil properties and existing land-use conditions across the watershed, The model was tested and calibrated on a natural watershed, The nature of the finite element procedure allowed changes in land-use to be easily incorporated into the model. The effect of several arbitrary land-use changes upon the response of the river under flood conditions was observed. The effect of changes in the number and size of the elements in the watershed and the streams was also observed along with changes in the size of the time increment.