Novel methodology for development of city scale hydrological-hydraulic models: from subcatchment delineation to calibration

Abstract

The study proposes a novel six-step methodology for the development of a city scale hydrological-hydraulic models with adequate spatial resolution. In an era of almost unlimited data, the key challenge is the selection of appropriate data sources and the rational use of data for time efficiency. The novel methodology uses the socio-economic sectors of the city of Girona and a simplified version of the Copernicus urban atlas data to create subcatchments of homogeneous land use type and similar sizes. Network topological consistency was conducted using a novel Python algorithm, based on graph theory. Flow routing from the catchments to the network considers terrain slope and maximum flow path distance. The result exhibits a spatial resolution capable of considering land use properties, while also avoiding a very high spatial resolution, to prevent complexities in the calibration process. The methodology was applied to Girona, Spain, resulting in 351 subcatchments. Preliminary results indicate that this semi-automated approach effectively balances spatial resolution and computational efficiency, providing a robust framework for urban hydrological-hydraulic modelling. Ongoing calibration efforts aim to further refine the model.