Évaluation de l'impact de l'urbanisation sur la réponse hydrologique de 172 bassins versants américains

Abstract

Urbanization and people concentration are suspected to have multiple impacts on the catchments hydrological response. Hydrologically relevant metric of land use change and climate variability identification still remain an open scientific question. Besides, at the catchment scale, urbanization impacts on flow are not easy to quantify and previous studies results appear quite disparate when assessing these impacts. The objective of this study is to investigate potential changes in catchments hydrological responses for the current urban surfaces (considered as less permeable). To this aim, the GR4J model, a conceptual daily 4 parameter hydrological model, was used to simulate discharge. In this study, 104 urban catchments and 68 non urban catchments in the United States were selected. Streamflow and rainfall data were collected with periods of 30 to 70 years. Ensemble of model parameter sets were calibrated for a sequence of 5 years sub periods and a simulation is performed with each set of parameters using the entire record period. Results showed that a majority of catchments did not present a significant trend over the record period for the hydrological properties analysed on the studied period for urban and non urban catchments.