Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 9

HEC-RAS Related Abstracts

9 Verification and Application of Finite Element Model Developed for Flood Routing in Rivers

Authors: A. L. Qureshi, A. A. Mahessar, A. Baloch

Abstract:

Flood wave propagation in river channel flow can be enunciated by nonlinear equations of motion for unsteady flow. However, it is difficult to find analytical solution of these complex non-linear equations. Hence, verification of the numerical model should be carried out against field data and numerical predictions. This paper presents the verification of developed finite element model applying for unsteady flow in the open channels. The results of a proposed model indicate a good matching with both Preissmann scheme and HEC-RAS model for a river reach of 29 km at both sites (15 km from upstream and at downstream end) for discharge hydrographs. It also has an agreeable comparison with the Preissemann scheme for the flow depth (stage) hydrographs. The proposed model has also been applying to forecast daily discharges at 400 km downstream from Sukkur barrage, which demonstrates accurate model predictions with observed daily discharges. Hence, this model may be utilized for predicting and issuing flood warnings about flood hazardous in advance.

Keywords: Flood Forecasting, Finite Element Method, Preissmann scheme, HEC-RAS, Indus river

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8 Dambreak Flood Analysis Using HEC-RAS and GIS Technologies

Authors: Oussama Derdous, Lakhdar Djemili, Hamza Bouchehed

Abstract:

The potential risks associated with dam break flooding could be considerable and result in major damage, including loss of life and property destruction. In the past, Algeria experienced such flood disasters; let’s recall the failure of Fergoug dam in 1881, this accident cost 200 lives, many houses and bridges were destroyed by the flooding. Recently the Algerian government have obligated to dam owners the development of detailed dam break Emergency Action Plans for its 64 major dams. The research presented here was conducted within this framework, Zardezas dam which is located in the city of Skikda in the North East of Algeria was the case of study. The model HEC-RAS was used for the hydrodynamic routing of the dam break flood wave. In addition, Geographic Information System (GIS) was used to create inundation maps and produce a visualization of the flood propagation in the Saf-Saf River.The simulation results that demonstrate the significance of Zardezas dam break flooding; constitute a real tool for developing emergency response plans and assisting territorial communities in land use planning.

Keywords: GIS, Emergency Action Plan, HEC-RAS, dam break, inundation maps

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7 River Analysis System Model for Proposed Weirs at Downstream of Large Dam, Thailand

Authors: S. Chuenchooklin

Abstract:

This research was conducted in the Lower Ping River Basin downstream of the Bhumibol Dam and the Lower Wang River Basin in Tak Province, Thailand. Most of the tributary streams of the Ping can be considered as ungauged catchments. There are 10- pumping station installation at both river banks of the Ping in Tak Province. Recently, most of them could not fully operate due to the water amount in the river below the level that would be pumping, even though included water from the natural river and released flow from the Bhumibol Dam. The aim of this research was to increase the performance of those pumping stations using weir projects in the Ping. Therefore, the river analysis system model (HEC-RAS) was applied to study the hydraulic behavior of water surface profiles in the Ping River with both cases of existing conditions and proposed weirs during the violent flood in 2011 and severe drought in 2013. Moreover, the hydrologic modeling system (HMS) was applied to simulate lateral streamflow hydrograph from ungauged catchments of the Ping. The results of HEC-RAS model calibration with existing conditions in 2011 showed best trial roughness coefficient for the main channel of 0.026. The simulated water surface levels fitted to observation data with R2 of 0.8175. The model was applied to 3 proposed cascade weirs with 2.35 m in height and found surcharge water level only 0.27 m higher than the existing condition in 2011. Moreover, those weirs could maintain river water levels and increase of those pumping performances during less river flow in 2013.

Keywords: HEC-RAS, HMS, pumping stations, cascade weirs

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6 Floodplain Modeling of River Jhelum Using HEC-RAS: A Case Study

Authors: Kashif Hassan, M.A. Ahanger

Abstract:

Floods have become more frequent and severe due to effects of global climate change and human alterations of the natural environment. Flood prediction/ forecasting and control is one of the greatest challenges facing the world today. The forecast of floods is achieved by the use of hydraulic models such as HEC-RAS, which are designed to simulate flow processes of the surface water. Extreme flood events in river Jhelum , lasting from a day to few are a major disaster in the State of Jammu and Kashmir, India. In the present study HEC-RAS model was applied to two different reaches of river Jhelum in order to estimate the flood levels corresponding to 25, 50 and 100 year return period flood events at important locations and to deduce flood vulnerability of important areas and structures. The flow rates for the two reaches were derived from flood-frequency analysis of 50 years of historic peak flow data. Manning's roughness coefficient n was selected using detailed analysis. Rating Curves were also generated to serve as base for determining the boundary conditions. Calibration and Validation procedures were applied in order to ensure the reliability of the model. Sensitivity analysis was also performed in order to ensure the accuracy of Manning's n in generating water surface profiles.

Keywords: HEC-RAS, flood plain, Jhelum, return period

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5 Vulnerability Assessment for Protection of Ghardaia City to the Inundation of M’zabWadi

Authors: Mustapha Kamel Mihoubi, Reda Madi

Abstract:

The problem of natural disasters in general and flooding in particular is a topic which marks a memorable action in the world and specifically in cities and large urban areas. Torrential floods and faster flows pose a major problem in urban area. Indeed, a better management of risks of floods becomes a growing necessity that must mobilize technical and scientific means to curb the adverse consequences of this phenomenon, especially in the Saharan cities in arid climate. The aim of this study is to deploy a basic calculation approach based on a hydrologic and hydraulic quantification for locating the black spots in urban areas generated by the flooding and to locate the areas that are vulnerable to flooding. The principle of flooding method is applied to the city of Ghardaia to identify vulnerable areas to inundation and to establish maps management and prevention against the risks of flooding.

Keywords: Cartography, Vulnerability, inundation, HEC-RAS, Alea, Beni Mzab, torrential, wadi

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4 Simulation of Flood Inundation in Kedukan River Using HEC-RAS and GIS

Authors: Muhammad B. Al Amin, Reini S. Ilmiaty, Sarino, Muzamil Jariski

Abstract:

Kedukan River is an artificial river which serves as a Watershed Boang drainage channel in Palembang. The river has upstream and downstream connected to Musi River, that often overflowing and flooding caused by the huge runoff discharge and high tide water level of Musi River. This study aimed to analyze the flood water surface profile on Kedukan River continued with flood inundation simulation to determine flooding prone areas in research area. The analysis starts from the peak runoff discharge calculations using rational method followed by water surface profile analysis using HEC-RAS program controlled by manual calculations using standard stages. The analysis followed by running flood inundation simulation using ArcGIS program that has been integrated with HEC-GeoRAS. Flood inundation simulation on Kedukan River creates inundation characteristic maps with depth, area, and circumference of inundation as the parameters. The inundation maps are very useful in providing an overview of flood prone areas in Kedukan River.

Keywords: HEC-RAS, inundation map, flood modelling, HEC-GeoRAS

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3 Stochastic Richelieu River Flood Modeling and Comparison of Flood Propagation Models: WMS (1D) and SRH (2D)

Authors: Maryam Safrai, Tewfik Mahdi

Abstract:

This article presents the stochastic modeling of the Richelieu River flood in Quebec, Canada, occurred in the spring of 2011. With the aid of the one-dimensional Watershed Modeling System (WMS (v.10.1) and HEC-RAS (v.4.1) as a flood simulator, the delineation of the probabilistic flooded areas was considered. Based on the Monte Carlo method, WMS (v.10.1) delineated the probabilistic flooded areas with corresponding occurrence percentages. Furthermore, results of this one-dimensional model were compared with the results of two-dimensional model (SRH-2D) for the evaluation of efficiency and precision of each applied model. Based on this comparison, computational process in two-dimensional model is longer and more complicated versus brief one-dimensional one. Although, two-dimensional models are more accurate than one-dimensional method, but according to existing modellers, delineation of probabilistic flooded areas based on Monte Carlo method is achievable via one-dimensional modeler. The applied software in this case study greatly responded to verify the research objectives. As a result, flood risk maps of the Richelieu River with the two applied models (1d, 2d) could elucidate the flood risk factors in hydrological, hydraulic, and managerial terms.

Keywords: Monte Carlo Simulation, Flood Modeling, HEC-RAS, model comparison, probabilistic flooded area, SRH-2D, WMS

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2 Application of Hydrologic Engineering Centers and River Analysis System Model for Hydrodynamic Analysis of Arial Khan River

Authors: Najeeb Hassan, Mahmudur Rahman

Abstract:

Arial Khan River is one of the main south-eastward outlets of the River Padma. This river maintains a meander channel through its course and is erosional in nature. The specific objective of the research is to study and evaluate the hydrological characteristics in the form of assessing changes of cross-sections, discharge, water level and velocity profile in different stations and to create a hydrodynamic model of the Arial Khan River. Necessary data have been collected from Bangladesh Water Development Board (BWDB) and Center for Environment and Geographic Information Services (CEGIS). Satellite images have been observed from Google earth. In this study, hydrodynamic model of Arial Khan River has been developed using well known steady open channel flow code Hydrologic Engineering Centers and River Analysis System (HEC-RAS) using field surveyed geometric data. Cross-section properties at 22 locations of River Arial Khan for the years 2011, 2013 and 2015 were also analysed. 1-D HEC-RAS model has been developed using the cross sectional data of 2015 and appropriate boundary condition is being used to run the model. This Arial Khan River model is calibrated using the pick discharge of 2015. The applicable value of Mannings roughness coefficient (n) is adjusted through the process of calibration. The value of water level which ties with the observed data to an acceptable accuracy is taken as calibrated model. The 1-D HEC-RAS model then validated by using the pick discharges from 2009-2018. Variation in observed water level in the model and collected water level data is being compared to validate the model. It is observed that due to seasonal variation, discharge of the river changes rapidly and Mannings roughness coefficient (n) also changes due to the vegetation growth along the river banks. This river model may act as a tool to measure flood area in future. By considering the past pick flow discharge, it is strongly recommended to improve the carrying capacity of Arial Khan River to protect the surrounding areas from flash flood.

Keywords: HEC-RAS, BWDB, CEGIS

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1 One Dimensional Flood Modelling Using River Analysis System-Mapper Tools in Hydrological Engineering Centers-River Analysis System: A Case Study on Purna River, Navsari City

Authors: Azazkhan Pathan, Prasit Agnihotri

Abstract:

The research is intended to utilize the RAS mapper tools capabilities in HEC-RAS (hydrological engineering centers-River Analysis System) for flood modelling in coastal side of Purna River without the need of Arc-GIS technology. Research shows the capabilities of the newest version of HEC-RAS 5.0.6, through which 30 m resolution DEM (Digital Elevation Model) and projection database have been used as an input data set as stream elevation information and maximum flow information, normal downstream slope has been used for steady flow assessment in this area of study. In the current research, river geometries such as river centerline, bank line, flow path line, and cross-section are created in RAS mapper tools present in HEC-RAS, which were earlier used in Arc-GIS and exported for model execution to HEC-RAS. It is, therefore, a big benefit that model simulation and flood mapping can be carried out in HEC-RAS simultaneously using RAS mapper. The depth of water, the velocity of low and the water surface elevation can be found by utilizing study flow analysis. Flood control authorities could use the findings of the research investigation to measure for the flood at different cross-sections.

Keywords: HEC-RAS, floodplain mapping, RAS-mapper

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