Integrated Hydrological-Hydraulic Model for Flood Simulation in Tropical Urban Catchment

Abstract

In recent decades, Malaysia has become one of the world’s most urbanized nations, causing severe flash flooding. Urbanization should meet the population’s needs by increasing the development of paved areas, which has significantly changed the catchment’s hydrological and hydraulic characteristics. Therefore, the frequency of flash flooding in Malaysia’s urban areas has grown year after year. Numerous techniques have been used, including the statistical approach, modeling, and storm design methods, in flood simulation. This research integrated hydrology and hydraulic models to simulate the urban flood events in the Aur River catchment. The primary objective is to determine water level and forecast peak flow based on hydrological assessment in the drainage system using XPSWMM software. The rainfall data for 60 min was used for this study in the hydrological analysis by obtaining an intensity-duration-frequency curve and peak flow value (Q peak). XPSWMM is used to simulate the response of a catchment to rainfall events in which runoff, water depth profile, and outflow hydrograph are obtained. Peak runoff is also obtained from the modified rational method for validation purposes. The proposed method was verified by comparing the result with the standard method. This is essential to identify flash flooding, which can lead to efficient flood mitigation planning and management in the urban catchment. The increase in residential areas results in the alteration of time of concentration, water quantity, and flow rate. Thus, to mitigate present and future problems, the effects of urbanization on water resources and flood should be analyzed.

Estimating the probability of compound floods in estuarine regions

“…A possible solution for addressing boundary condition non-stationarity is to widen the modelling chain, thereby explicitly representing a broader range of physical processes in the model (Heavens et al, 2013). For example, land-use change or the construction of a reservoir in the upstream catchment can lead to significant non-stationarity in streamflow time series (the upper boundary condition in the pre-ceding example), and this could be addressed by extending the boundary condition further up to time series of historical rainfall (Hasan et al, 2019). From there it becomes possible to explicitly model the key flow-generation processes (including the effects of land-use change and/or reservoirs) before coupling this to a hydrodynamic model of the estuary.…”

Urban stormwater characterization, control, and treatment

“…The stormwater management model (SWMM) developed by the U.S. EPA is a common approach used by researchers for modeling of urban stormwater movement at watershed scales. SWMM was used to simulate flood events in an urbanized 3,978‐ha catchment in Malaysia (Hasan, Mohd Razali, Ahmad Zaki, & Mohamad Hamzah, 2019). The catchment boundaries were delineated using digital terrain models from LiDAR data, IKONOS satellite imagery, and on‐ground verification.…”

Enhancing an Analysis Method of Compound Flooding in Coastal Areas by Linking Flow Simulation Models of Coasts and Watershed

“…XP-SWMM is a fully, dynamic hydraulic and hydrologic modeling software that combines 1D calculations for upstream to downstream flow with 2D overland flow calculations [34]. XP-SWMM, developed by XP Solutions Inc. [35][36][37], is highly utilized for urban flooding simulations around the world [38][39][40][41]. Therefore, XP-SWMM was used to analyze runoff of watersheds and inundation in coastal areas in this study.…”