Work

Methodological approaches for numerical integration of culverts in 2D surface models in urban flood analysis

Year: 2025

Type: article

Abstract: Urban flood response at road crossings hinges on how short conveyance structures are represented. In our study, each location in the watercourse is not modelled as a bridge per se but alternatively represented as (i) oDEM - a terrain opening that preserves open-channel through-routing; (ii) Culvert - an explicit 1D element transferring flow between inlet and outlet via head-loss formulations; or (iii) Sewer - a short 1D sewer network element (using SWMM) coupled to the surface. As a control, (iv) cDEM enforces overtopping-only exchange to emulate hydraulically ineffective bridge passages. We provide a scenario-controlled, side-by-side benchmark of these four approaches across five sites and three precipitation types (Euler-II 30-year, Euler-II 100-year, and a duration-matched 100-year block event), comparing discharge timing, maximum water depths, flooded area, and end-of-run water balances. Across scenarios, oDEM and Culvert preserve longitudinal connectivity, yielding broader-but-shallower upstream extents and higher boundary outflow, whereas cDEM and Sewer promote upstream storage and compact, deeper ponds. Our contribution is a controlled comparison that clarifies when each representation is fit-for-purpose: for short crossings, the Culvert representation emerges as a practical baseline that captures inlet/outlet losses and pressurised/free-surface transitions, while Sewer may over-retain heads where surface–sewer coupling footprints are restrictive. oDEM and cDEM can be read as bounding models - oDEM as an optimistic high-connectivity envelope, cDEM as a conservative overtopping-only envelope—to bracket plausible responses where calibration data are scarce.

Source: Journal of Hydrology

DOI: 10.1016/j.jhydrol.2025.134728

Authors: Michael Oberauer, Boris Lehmann, Andreas Buttinger-Kreuzhuber, Jürgen Waser

Institutions: Technische Universität Darmstadt, VRVis GmbH (Austria)

Language: English

Topic: Flood Risk Assessment and Management

Subfield: Global and Planetary Change

Field: Environmental Science

Domain: Physical Sciences

SDGs: Sustainable cities and communities, Clean water and sanitation

Open Access status: hybrid

Estimated APC paid: $4,030