Urban Flood Modeling Using 2D Shallow-Water Equations in Ouagadougou, Burkina Faso

Abstract

Appropriate methods and tools accessibility for bi-dimensional flow simulation leads to their weak use for floods assessment and forecasting in West African countries, particularly in urban areas where huge losses of life and property are recorded. To mitigate flood risks or to elaborate flood adaptation strategies, there is a need for scientific information on flood events. This paper focuses on a numerical tool developed for urban inundation extent simulation due to extreme tropical rainfall in Ouagadougou city. Two-dimensional (2D) shallow-water equations are solved using a finite volume method with a Harten, Lax, Van Leer (HLL) numerical fluxes approach. The Digital Elevation Model provided by NASA’s Shuttle Radar Topography Mission (SRTM) was used as the main input of the model. The results have shown the capability of the numerical tool developed to simulate flow depths in natural watercourses. The sensitivity of the model to rainfall intensity and soil roughness coefficient was highlighted through flood spatial extent and water depth at the outlet of the watershed. The performance of the model was assessed through the simulation of two flood events, with satisfactory values of the Nash–Sutcliffe criterion of 0.61 and 0.69. The study is expected to be useful for flood managers and decision makers in assessing flood hazard and vulnerability.

Dynamic Assessment of the Impact of Flood Disaster on Economy and Population under Extreme Rainstorm Events

“…The two river outlets (Figure 2b) located at the Hongwanchong and Qianshan River and two typical pipes (Figure 2a) in the study area were selected. The simulation results of the scalar flowrate time series (Figure 6) at the two basin outlets showed that the model had a high stability, and the flow processes of the two outlets were consistent with other similar studies [45,46]. The typical pipe discharge was also evaluated (Figure 7).…”

Exploitation of indigenous bamboo macrophyte species and bamboo biochar for faecal sludge treatment with constructed wetland technology in the Sudano-Sahelian ecological zone

“…However, monthly minimum and maximum temperatures varied from 11.1 to 22.4 °C and 33.7–43.1 °C respectively. The monthly relative humidity ranged between 29.91 and 86.71%, with an average of 55.98% ( Figure 3 ) Coulibaly et al. (2020) reported an average daily minimum and maximum temperature of 16 and 40 °C respectively, and a relatively lower mean annual precipitation of 788 mm Ibrahim et al.…”

The assessment for selection and correction of RS‐based DEMs and 1D and 2D HEC‐RAS models for flood mapping in different river types

“…Hydraulic models are mathematical models that replicate water movements by solving equations derived from conservation laws of mass, energy, and momentum (Coulibaly et al, 2020). All hydraulic models are sensitive to geometric and physical descriptions of the river, such as number of cross‐sections, spacing between cross‐sections, bottom slope, bathymetric point data, quality of the mesh, model parameters (Manning's n), and the structural type of model (i.e., 1D, 2D or 3D).…”