Flood risk in Kuala Lumpur, Malaysia: A consideration of flood defences in a broadscale hydraulic model

Abstract

A novel approach to consider local‐scale defence infrastructure in an urban environment, coupled with a broadscale hydraulic model framework, is applied to the capital city of Kuala Lumpur, Malaysia. Broadscale hydraulic modelling frameworks are often able to employ more complex models, but are typically limited to homogenous decision‐making to ensure standardised outputs across large regions. Conversely, small‐scale hydraulic modelling frameworks tend to better integrate local‐scale features but can be computationally expensive to scale up beyond a regional view. Improvements to the broadscale hydraulic model framework through the incorporation of defence systems yield a more accurate representation of fluvial flood risk. This study incorporates defences in Kuala Lumpur, yielding a reduction in our estimates of fluvial flood extent by around 40%. The results of this study are validated against a set of high‐quality observations, demonstrating the capability of the model framework in capturing flood risk in more than 95% of known flood risk zones in the city. Incorporating defence infrastructure using data‐driven decision making and existing functionality in the hydraulic model could be automated in future model builds. This new approach bridges the gap between local‐scale model frameworks and the broadscale, homogenous 2D hydraulic modelling studies.

Integration of Geoscience Information for Disaster Resilience in Kuala Lumpur, Malaysia

“…After validation using the compilation of flood incidents spanning 1977-2020, nearly 92% of the 569 flood locations are within the extent of the susceptibility zones. A comparison of modelled data with known discharge rates through the tunnels and expected rates of flow downstream of inlet and outlet ponds confirm that the model set-up successfully reconstructs the water retention and diversion in Kuala Lumpur in the defended scenario [50].…”

“…Climate change is making extreme weather events more common, and proactive steps are required to address these challenges. A robust approach has recently been introduced to delineate areas susceptible to landslides and floods, but more work is required to link this to the planning process [18,50].…”

“…The flood extent defined by 200-year return periods represents zones with potential for flooding. From the selected criteria, landslide is given a higher weightage because the intensity of landslide events is higher than that of floods [18,50]. Scores of 1, 3, 5, and 7 are given to negligible geohazard, flood, landslide and both geohazards (figure in Section 3.3).…”

“…Two types of validation were conducted. Comparison with historical flood events was used to validate the flood extent, and the discharge rates through culverts were used to validate the defended flood scenario [50].…”

Preparing for severe flooding: Flood risk management research leading to better flood preparedness

“…Development and optimization of tools and approaches towards understanding flooding potential and evaluating flood risk management approaches are also required to improve flood preparedness. This is exemplified in this issue by several studies into new approaches for numerical modelling tools in flood simulation, including the effect of cross-sectional orientation in a one-dimensional hydrodynamic model on variability in model flood simulations (Jesna et al, 2023), incorporation of spatially distributed precipitation into a two-dimensional hydraulic model for a vulnerable, steepterrain catchment (Godara et al, 2023), integration of local-scale features into a hydraulic modelling framework to improve model representation of local urban flood defence infrastructure (Massam et al, 2023), and the relationship between spatiotemporal catchment hydrological processes and the calibration process in hydrologicalhydrodynamic models (David et al, 2023). A new modelling approach for critical infrastructure networks that can be disrupted by flooding is explored by Schotten and Bachmann (2023).…”