Uncertainties of Cultivated Landscape drainage Network Mapping and its Consequences on Hydrological Fluxes Estimations

I-lorent Levavasseur1, Philippe Liigacherie1, Michael Rabotin1, Jean-Stephane Bailly2, Francois Colin3
1."iJMR 1221 LISAH, F-34035, INRA, Montpellier, France
2. UMR1221 LISAH, F-34035, UMR TET1S, F-34093, AgroParisTech, Montpellier, France
3. UMR 1221 LISAH, F-34035, Montpellier SupAgro, Montpellier, France
1. {levavass lagache rabotin}@supagro.inra.fr 2. jean-stephane.bailly@teledetection.fr 3. francois.colin@supagro.inra.fr

Abstract: In this study, we use a network generation method to simulate equi-probable artificial drainage networks on a small Mediterranean cultivated catchment. The method consists in a stochastic algorithm assimilating sampled observations on the network that generates a ditch network based on the map of field boundaries. A set of one hundred simulations is used to represent the uncertainty on the ditch network. With regards to geometrical (lengths indices), topological (Shreve indices) and topographical metrics (slope indices), simulations similarities compared to the real network are computed. Secondly, uncertainty on the network is propagated through the hydrological model MHYDAS. The induced hydrological responses in hydrographs present a variability that can be linked to previous networks metrics. At this stage of the network generation process, this uncertainty propagation study allows to drive the choice of criteria for future network generation process improvement.

Keywords: artificial drainage network, directed tree, uncertainties, mapping, error propagation, hydrological response.

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