Integrated mathematical modeling of hydrological and hydrodynamic response to rainfall events in rural lowland catchments

Abstract

In rural lowland catchments, negligible topographic gradients and possible interactions between overland and channel flows complicate efforts to predict flood formation, propagation, and inundation. In this study, we demonstrate that an approach in which a two-dimensional shallow water model is coupled with a two-dimensional model for the saturated flow in the topsoil layer can accurately reproduce floods in such a lowland catchment. The topsoil porous layer is treated as a confined aquifer where water ponds on the ground surface and as an unconfined aquifer elsewhere. The model includes infiltration from the ground surface into the topsoil layer and downward percolation out of the topsoil layer. The equations of both surface and subsurface models are suitably averaged over a representative elementary area to yield a subgrid model for the coupled surface-subsurface flow. Field data collected in two rural lowland catchments in the North-East of Italy are used to evaluate the model performance. The good agreement between computed and measured discharge at the catchments' outlet and the agreement between predicted and surveyed spatial pattern of inundated areas indicate that the model effectively reproduces overland flow and efficiently accounts for the surface-subsurface flow interaction and the relevant subsurface processes.

Urban flood modeling using shallow water equations with depth-dependent anisotropic porosity

“…In shallow water modeling of river hydraulics (Özgen et al, 2013;Kesserwani and Liang, 2015), urban flooding (Liang, 2010;Mignot et al, 2006), urban runoff (Cea et al, 2010;Liang et al, 2007;Liang et al, 2015) and rainfall-runoff on natural environments (Mügler et al, 2011;Özgen et al, 2015;Simons et al, 2014;Viero et al 2014), the topographical features have a large influence on the numerical results. The availability of digital elevation data has increased significantly due to recent improvements in surveying technology, notably laser scanning and light detection and ranging (LIDAR) technologies, which provide high-resolution data sets at relatively low cost (Gessner et al, 2014;Gourbesville, 2009).…”

“…The distribution function is defined for the whole domain. In Viero et al 2014, Defina's porous shallow water equations are applied to coupled simulations of surface and subsurface flows in natural catchments.…”

Hydrological Response to ~30 years of Agricultural Surface Water Management

“…The negligible topographic gradients and possible interactions between overland and channel flows constitute the main limitation to predict flood formation, propagation, and inundation [78]. As well, changes in arable production have been associated with pressures to work land unsuitable for production [79] or already involved in hydraulic criticalities.…”

Physically based modeling in catchment hydrology at 50: Survey and outlook

“…The stream components of these coupled models are innovative in that they necessarily differ conceptually from open channel models. Additional studies in riparian and lowland environments have examined: links in runoff dynamics from landscape elements to the channel network and the relative contributions of hillslope and riparian zones to streamflow response [ McGlynn and McDonnell , ; Jencso et al ., ]; hydrological connectivity across the hillslope/riparian/channel continuum, threshold runoff responses, groundwater ridging, and hysteretic behavior in catchment storage‐discharge relationships [ Bates et al ., ; McGuire and McDonnell , ; Mahmood and Vivoni , ; Weill et al ., ; Camporese et al ., ; Pierini et al ., ]; impacts of land clearance (removal of deep‐rooted vegetation) in the hyporheic zone on the state of connection between an aquifer and a river [ Banks et al ., ]; and flood formation, propagation, and inundation dynamics with a coupled 2‐D SWE and saturated groundwater model [ Viero et al ., ].…”