Simplified Flood Inundation Model Integrating with Rainfall-runoff Processes (original) (raw)
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PROCEEDINGS OF HYDRAULIC ENGINEERING, 2008
Flood hazard is the one of the most harmful disasters in the world, therefore it is significant to obtain reliable information on flood characteristics for flood hazard mitigation as well as flood vulnerability assessment. Hereby in order to obtain the temporal-spatial distribution of flood hazard vulnerability, a grid cell based simplified flood inundation simulation integrating with rainfall-runoff processes is developed in this study for flood inundation simulation of large watersheds, which is based on 1-D channel flow routing, and 2-D overland and slope flow routing simulation model. According to flood inundation simulation, flood characteristics can be analyzed, especially the flood-prone area is able to be identified and delineated. This paper describes the background of the model development and methodology.
An Integrated One-Dimensional and Two-Dimensional Urban Stormwater Flood Simulation Model
Journal of the American Water Resources Association, 2006
Flash flooding is the rapid flooding of low lying areas caused by the stormwater of intense rainfall associated with thunderstorms. Flash flooding occurs in many urban areas with relatively flat terrain and can result in severe property damage as well as the loss of lives. In this paper, an integrated one-dimensional (1-D) and two-dimensional (2-D) hydraulic simulation model has been established to simulate stormwater flooding processes in urban areas. With rainfall input, the model simulates 2-D overland flow and 1-D flow in underground stormwater pipes and drainage channels. Drainage channels are treated as special flow paths and arranged along one or more sides of a 2-D computational grid. By using irregular computation grids, the model simulates unsteady flooding and drying processes over urban areas with complex drainage systems. The model results can provide spatial flood risk information (e.g., water depth, inundation time and flow velocity during flooding). The model was applied to the City of Beaumont, Texas, and validated with the recorded rainfall and runoff data from Tropical Storm Allison with good agreement.
Reliability of 2D Hydrodynamic Model on Flood Inundation Analysis
International Journal of GEOMATE, 2021
This paper presents a flood inundation analysis to determine the possibility of flooding in urban areas. Many studies have conducted flood simulations to generate inundation problems due to river overflow. Urban flood problems commonly occur because of rainfall in subcatchments that do not enter the channel effectively. Therefore, it is necessary to analyze the inundation that occurs owing to overland flow. This study investigates the usefulness of rain-on-grid boundary conditions compared to flow hydrographs to represent the overland flow. The 2D shallow water equation was applied using the HEC RAS 2D model to select suitable boundary conditions to describe watershed problems. The rain-on-grid boundary condition gives a direct rainfall-runoff calculation in the simulation. The flow hydrograph was calculated separately using the rainfallrunoff analysis based on the storm-water-management model. Although rain-on-grid represents the real physical condition, it is difficult for the 2D hydrodynamic model to assess the drainage channel. However, the flow hydrograph boundary condition shows good results compared qualitatively with historical data based on on-site observations obtained from the Department of Public Works, Highways, and Drainage Management. Furthermore, this research provides the capability of flow hydrographs and rain-on-grid boundary conditions for flood simulation in urban areas. The results can be used to conduct an appropriate future simulation of urban drainage planning.
River flood is recurrent natural phenomena in tropics and sub tropical climate. Among all kinds of natural hazards of the world flood is probably most wide spread, frequent and destructive. In recent years, remote sensing and GIS has become the key tool for flood modeling. This paper will discuss the modeling of floodplain by integrated hydrological with hydraulic model. The hydrologic model will determine the runoff that occurs following a particular rainfall event. The primary output from the hydrologic model is hydrographs at varying locations along the waterways to describe the quantity, rate and timing of stream flow that results from rainfall events. These hydrographs then become a key input into the hydraulic model. The hydraulic model simulates the movement of flood waters through waterway reaches and calculates flood levels and flow patterns. Furthermore, 2D simulation will apply to simulate and analysis of river flows with complex topography and to predicting river bed and...
A Raster-Based Stormwater Simulation Model and Its Application in Inundation Mitigation Planning
PROCEEDINGS OF HYDRAULIC ENGINEERING, 2008
A raster-based stormwater simulation model is formulated and applied in this study. The proposed model employs the raster-based distributed approach for describing the surface rainfall runoff process. Surface runoff is generated from each grid cell and then is routed to the inlets/manholes of drainage channel network by using 2-D diffusion wave. The hydraulic process in the drainage channel network is performed by using the EXTRAN module, a component of the Storm Water Management Model (SWMM). The input flow rate at inlets is calculated by using weir equation. The surcharge outflow rate from the drainage channels is calculated by using Preissman slot concept. The proposed model is successfully applied to reproduce the heavy flood event on August 4, 1998 in Kamedagou basin, Niigata Prefecture, Japan. Further more, the well-calibrated stormwater simulation model is utilized to inundation mitigation planning in the study area.
A rapid flood inundation model in the floodplain area due to an extreme rainfall event
E3S Web of Conferences, 2021
Extreme rainfall in East Jakarta on February 19, 2021 caused flooding in a number of subdistricts. The research was conducted in the central part of Kali Sunter, which flows through three subdistricts, namely Cipinang Melayu, Cipinang Muara, and Pondok Bambu. The purpose of the study was to do flood hazard modeling and analyze the characteristics of flood-affected areas based on land use and topography. Inundation and flood hazard maps is done by: calculating the flood discharge using the SCS-CN method, flood inundation modelling using HEC-RAS, and analyzing the characteristics of the inundated area. This combination is effective for rapid modeling during extreme rainfall events. Based on the research, the distribution of the highest flood hazard area is in RW 004 Cipinang Melayu, with the widest inundation affecting small and medium-sized houses. The characteristics of the affected area are that there is green and empty land which reduces the potential for water to inundate buildin...
The Role Of One- And Two-dimensionalMathematical Models For Flood Risk Simulation
2005
With regard to the aspects of river basin management, mathematical flood modelling can be a valuable tool in order to simulate hazardous effects both in rural as well as in urban river basins. In a strict mathematical sense there is no need to work with momentum equations in two plane dimensions, and it may be sufficient to assume that the flow occurs along pre-defined directions in space, resulting in the so-called pseudo two-dimensional model, also known as the flow cell model. Generally, in most rural areas, one-dimensional models give good results as the river flow can be considered to occur in a preferential space direction. In this case, the river is assumed to flow in a straight way only at each sub-reach and the flooding levels are extrapolated to the floodplains without significant errors. However, when studying urban and some particularly flat rural areas, one may notice that frequently the one-dimensional approach may lack the flood pattern meanings. In such cases, a pseu...
Modelling of Floodplain Using Recent Technology
2015
Floodplains are land areas adjacent to rivers and streams that are subject to recurring inundation. Owing to their continually changing nature, floodplains and other flood-prone areas need to be examined in the light of how they might affect or be affected by development A Floodplain is the normally dry land area adjoining river or stream that is inundated during flood events. The most common reason for flooding could be overtopping of river or stream due to heavy downfall. The floodplain carries flow in excess of the river or stream capacity. Flood frequency and flood water-surface elevations are the crucial components for the evaluation of flood hazard. This Review paper presents the recent methodology that incorporates advanced technologies for hydrologic and hydraulic analyses that are needed to be carried out to predict the flood water-surface elevations for any ungagged watershed.
Large-scale Flood Simulation with Rainfall-Runoff-Inundation Model in the Chao Phraya River Basin
A large amount of rainfall during the 2011 monsoonal season caused an unprecedented flood disaster in the Chao Phraya River basin in Thailand. When a large-scale flood occurs, it is very important to take appropriate emergency measures by holistically understanding the characteristics of the flooding based on available information and by predicting its possible development. This paper proposes quick response-type flood simulation that can be conducted during a severe flooding event. The hydrologic simulation model used in this study is designed to simulate river discharges and flood inundation simultaneously for an entire river basin with satellite based rainfall and topographic information. The model is based on two-dimensional diffusive wave equations for rainfall-runoff and inundation calculations. The model takes into account the effects of lateral subsurface flow and vertical infiltration flow since these two types of flow are also important processes. This paper presents predi...
Simulation of Flood Risk Area in Kelantan Watershed, Malaysia Using Numerical Model
Jurnal Teknologi, 2016
Flood events have recently increased and caused extensive damages to the agricultural area and infrastructures, despite enormous efforts to decrease this hazard. Modeling of runoff can be a suitable approach to determine the effective factors in flooding, and to explore reasonable solution and thus to be able reduce hazard on watersheds. The current work attempted to derive basin and sub-basins, stream network, aspect, slop and all relevant physiographic parameters of Kelantan watershed in order to estimate depth of runoff using DEM data , satellite images and field study. In addition, the maximum rainfall intensity of all the meteorological stations were extracted and the interpolation of the values obtained, led to derive a contour map as rainfall intensity for the watershed. Soil Conservation Service (SCS) model was employed to calculate the surface flows, and to derive the flood hydrograph for all the sub-basins at the return periods of 5,10,25,50,100, considering to th...