A mathematical model for calculating river hydrographs using high resolution digital elevation models
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Prediction of floods is important to prevent damage to human lives, build-ings or infrastructure, and we have developed a simulation model to addressthis. The model is a so-called distributed rainfall-runoff model, which accountsfor spatial variations within the watershed; it is based on a distributed versionof the time-area method (Clark, 1945). Travel times are calculated by assumingthat the flow can be modelled as creeping flow, and the resulting velocity field isused to solve the so-called time-of-flight/Eikonal equation. Both topographicaland heterogeneous properties can be accounted for by the model, which ideallycan be used for both gauged and ungauged watersheds after calibration. Anautomatic watershed delineation algorithm has been implemented to delineatethe river s watershed using the D8 Algorithm (O Callaghan and Mark, 1984).To test our model, we create artificial rainfalls, and calculate the hydrograph re-sponse at the watershed outlet. The model works well given the simplifications,and is a framework which can be expanded upon and made more complex.