Simulation of Dam-Break Flood Wave and Inundation Mapping: A Case study of Attabad Lake

The break study of Landslide or embankment dams is more essential due to uncertainty in their composition and lack of knowledge of their response to other natural events because they are natural and not properly designed for any disaster. The paper aims to improve different methods of hydraulic modeling of dam break. In this present study dam break of Attabad lake is simulated using the computational fluid dynamics technique. The numerical model (FLOW-3D) is developed to solve the Reynolds averaged Navier-Stoke equation fully in 3D to predict peak flow depth at different cross-sections, peak velocity, peak discharge, time to peak depth, and time to peak discharge. The standard RNGturbulence model is employed to simulate turbulence and then flood inundation maps and velocity vectors for flow at villages are drawn. The results show that most of the flood wave modeled through the Hunza river channel, is contained by the flood plain of Hunza River but for some of the villages i.e. Miaun and chalat, which are situated inside the flood plain of Hunza River are at higher risk of inundation but the flood arrival time estimated for these villages is 31 and 44 min respectively which is enough time for the evacuation of the population to safer areas while for some villages like Hassan Abad situated adjacent to Ali Abad is at higher risk of inundation while the estimated flood arrival time for the village is 12 min which are not enough for the evacuation of the population hence will need some extra flood protection structures for flood containment. The estimate of the peak velocities implies higher shear stress in the river plain, risk of heavy erosion, damage to agricultural lands, residencies, and morphological changes are projected. The analysis of the dam break i.e. Peak depths, Peak Velocities, flood arrival time, and flood inundation maps should only be used as a guide in future risk analysis and flood management.

Download Full-text

Combined Influence of Terrain Modell and Roughness in Dam Break Wave Simulation

E3S Web of Conferences ◽

10.1051/e3sconf/20184006026 ◽

2018 ◽

Vol 40 ◽

pp. 06026

Author(s):

Antje Bornschein

Keyword(s):

Arrival Time ◽

Dam Break ◽

Flood Wave ◽

Sources Of Uncertainty ◽

Wave Simulation ◽

Terrain Models ◽

Maximum Water Level ◽

Calculation Results ◽

Maximum Water ◽

Different Sources

Dam break wave simulation provides data for emergency management. The calculation results should be as accurate as possible. The modeler has to deal with different sources of uncertainty. The paper presents dam break calculation for three different dams in order to assess the uncertainty due to the chosen model (1D or 2D), different terrain models and different Manning's n values. The comparison of the calculation results is focused on the maximum discharge, maximum water level and flood wave arrival time.

Download Full-text

Dam Break Modeling in a Cascade of Small Earthen Dams: Case Study of the Čižina River in the Czech Republic

Water ◽

10.3390/w12082309 ◽

2020 ◽

Vol 12 (8) ◽

pp. 2309

Author(s):

Jaromír Říha ◽

Stanislav Kotaška ◽

Lubomír Petrula

Keyword(s):

Hydraulic Modeling ◽

Dam Break ◽

Peak Discharge ◽

Flood Routing ◽

Small Reservoirs ◽

Small Dams ◽

Flood Volume ◽

Exponential Trend ◽

Earthen Dams

Failures of small dams can pose a serious threat to people and property even if the size of the schemes is relatively low. In many cases, small dams are situated in a cascade along streams, meaning that the failure of the uppermost dam may cause the dams downstream to fail. In this paper, a cascade of three small reservoirs, Lichnov II (14.6 m high), Lichnov III (10 m high), and Pocheň (8.5 m high), is the subject of the dam break analyses carried out via various methods such as empirical formulae, analogy, and hydraulic modeling. The dam-break flood routing was simulated using a shallow water flow hydraulic model. The simulations confirm that the attenuation effect of the peak discharge is governed by the flood volume, slope, and morphology of the floodplain and increases with the distance from the breached dam following an approximately exponential trend. When estimating peak discharge, empirical formulae derived for a single dam break should be applied carefully as they may underestimate the peak outflow by up to 10% in the case of a dam cascade. The attenuation volume of small reservoirs is small when compared to the flood volume, meaning that the attenuation of the peak discharge usually varies between 5–10%.

Download Full-text

2D-HEC-RAS Modeling of Flood Wave Propagation in a Semi-Arid Area Due to Dam Overtopping Failure

Civil Engineering Journal ◽

10.28991/cej-2021-03091739 ◽

2021 ◽

Vol 7 (9) ◽

pp. 1501-1514

Author(s):

Ibtisam R. Karim ◽

Zahraa F. Hassan ◽

Hassan Hussein Abdullah ◽

Imzahim A. Alwan

Keyword(s):

Wave Propagation ◽

Flow Velocity ◽

Water Depth ◽

Dam Break ◽

Flood Wave ◽

Dam Breach ◽

Inundation Maps ◽

Overtopping Failure ◽

Dam Overtopping ◽

The Impact

Dam overtopping failure and the resulting floods are hazardous events that highly impact the inundated areas and are less predictable. The simulation of the dam breach failure and the flood wave propagation is necessary for assessing flood hazards to provide precautions. In the present study, a two-dimensional HEC-RAS model was used to simulate the flood wave resulting from the hypothetical failure of Al-Udhaim Dam on Al-Udhaim River, Iraq, and the propagation of the resulting dam-break wave along 100 km downstream the dam site for the overtopping scenario. The main objective is to analyze the propagation of the flood wave so that the failure risk on dam downstream areas can be assessed and emergency plans may be provided. The methodology consisted of two sub-models: the first is the dam breach failure model for deriving the breach hydrograph, and the second is the hydrodynamic model for propagating the flood wave downstream of the dam. The breach hydrograph is used as an upstream boundary condition to derive the flood impact in the downstream reach of Al- Udhaim River. The flood inundation maps were visualized in RAS-Mapper in terms of water surface elevation, water depth, flow velocity, and flood arrival time. The maximum recorded values were: 105 m (a.m.s.l.), 18 m, 5.5 m/s, and, respectively. The flow velocity decreased from upstream to downstream of the terrain, which means less risk of erosion in the far reaches downstream of the study area. The inundation maps indicated that the water depth and flow velocity were categorized as Catastrophic limits on the terrain's area. The results offer a way to predict flood extent and showed that the impact of a potential dam break at Al-Udhiam Dam will be serious, therefore, suitable management is needed to overcome this risk. Moreover, the maps produced by this study are useful for developing plans for sustainable flood management. Doi: 10.28991/cej-2021-03091739 Full Text: PDF

Download Full-text

Modelling of Flood Inundation due to Levee Breaches: Sensitivity of Flood Inundation against Breach Process Parameters

Water ◽

10.3390/w12123566 ◽

2020 ◽

Vol 12 (12) ◽

pp. 3566

Author(s):

Yohannis Birhanu Tadesse ◽

Peter Fröhle

Keyword(s):

Numerical Model ◽

Process Parameters ◽

Flood Plain ◽

Flood Event ◽

Flood Inundation ◽

Inundation Maps ◽

Levee Breach ◽

Negligible Influence

This paper analyses the sensitivity of flood inundation due to river levee breach against breach process parameters using the 1996 Awash River levee breach case at Wonji, Ethiopia. A parametric levee breach model integrated into the 2D hydrodynamic numerical model Telemac-2D is used to simulate a levee breach flood event at Wonji, Ethiopia. Levee breach process parameters are systemically varied to find out their effect on the flood inundation. The analysis of the model results shows that the flood inundation is sensitive to the final breach dimensions and breach location. However, the parameters describing the levee breach development have negligible influence on the flood inundation. This implies that final breach dimension and breach location in an event of levee breach are the most important and decisive parameters affecting the resulting inundation of the flood plain, and as such should be given due consideration when creating flood inundation maps due to levee breach.

Download Full-text

Near-real-time simulation and internet-based delivery of forecast-flood inundation maps using two-dimensional hydraulic modeling--A pilot study for the Snoqualmie River, Washington

10.3133/wri024251 ◽

2002 ◽

Keyword(s):

Pilot Study ◽

Real Time ◽

Hydraulic Modeling ◽

Flood Inundation ◽

Two Dimensional ◽

Real Time Simulation ◽

Inundation Maps ◽

Time Simulation

Download Full-text

Application of GIS, Hydraulic and Hydrologic Modelling to Investigate the Changes of Flood Inundation Characteristics due to the Construction of Dams for different scenarios

International Journal of Computational Physics Series ◽

10.29167/a1i2p61-77 ◽

2018 ◽

Vol 1 (2) ◽

pp. 61-77

Author(s):

Hossameldin M. Elhanafy

Keyword(s):

Fluid Mechanics ◽

Flood Control ◽

Reduction Rate ◽

Hydraulic Modeling ◽

Direct Result ◽

Flood Inundation ◽

High Ability ◽

The West ◽

Hydrologic Modelling ◽

New Location

The novelty of the research project reported in this paper is the coupling of hydrological and hydraulic modeling which are based on the first principal of fluid mechanics for the simulation of flash floods at Wadi Elarish watershed to optimize the a new location of another dam rather than Elrawfa dam which already exist. Results show that, the optimum scenario is obtained by the construction of the west dam. As a direct result of this dam, the downstream inundated area can be reduced up to 15.7 % as function of reservoir available storage behind the dam. Furthermore, calculations showed that the reduction rate of inundated area for 50-year floods is largely more than 100-year floods, implies the high ability of west dam on flood control especially for floods with shorter return period.

Download Full-text