Numerical Simulation of Flood Wave Propagation in Two-Dimensions in Densely Populated Urban Areas due to Dam Break

Abstract

Dams are important structures having many functions such as water supply, flood control, hydroelectric power and recreation. Although dam break failures are very rare events, dams can fail with little warning and the damage at the downstream of the dam due to the flood wave can be catastrophic. During a dam failure, immense volume of water is mobilized at very high speed in a very short time. The momentum of the flood wave can turn to a very destructive impact force in residential areas. Therefore, from risk point of view, understanding the consequences of a possible dam failure is critically important. This study deals with the methodology utilized for predicting the flood wave occurring after the dam break and analyses the propagation of the flood wave downstream of the dam. The methodology used in this study includes creation of bathymetric, DEM and land use maps; routing of the flood wave along the valley using a 1D model; and two dimensional numerical modeling of the propagation and spreading of flood wave for various dam breaching scenarios in two different urban areas. Such a methodology is a vital tool for decision-making process since it takes into account the spatial heterogeneity of the basin parameters to predict flood wave propagation downstream of the dam. Proposed methodology is applied to two dams; Porsuk Dam located in Eskişehir and Alibey Dam located in Istanbul, Turkey. Both dams are selected based on the fact that they have dense residential areas downstream and such a failure would be disastrous in both cases. Model simulations based on three different dam breaching scenarios showed that maximum flow depth can reach to 5 m at the border of the residential areas both in Eskişehir and in Istanbul with a maximum flow velocity of 5 m/s and flood waves having 0.3 m height reach to the boundary of the residential area within 1 to 2 h. Flooded area in Eskişehir was estimated as 127 km 2 , whereas in Istanbul this area was 8.4 km 2 in total.

A comprehensive flood event specification and inventory: 1930–2020 Turkey case study

“…Known flood extent can be used from a historical flood event to quantitatively validate the flood susceptibility model [13]. Standard engineering practices for flood risk assessment of a new or an existing settlement require to review the flood history and characteristics of the area [13][14][15]. Historical flood information can also help to improve our understanding of developmental stages of various flood hazards and risks [16,17] and social, physical and economic [18] which eventually leads us to better methods and mathematical models to describe those events.…”

A review of structural approach to flood management in coastal megacities of developing nations: current research and future directions

“…A significant number of studies have therefore focused on dam-break flood routing. For example, Haltas, Elçi, and Tayfur (2016) proposed a methodology for predicting how flood waves will propagate to densely populated areas located downstream of a failed or broken dam. Their methodology, based on the digital elevation model (DEM), land use maps, bathymetric data and flood wave routing models, was used to simulate dam breach scenarios in two different urban areas, including Istanbul, Turkey.…”

“…When a dam fails, the momentum of the flood wave can potentially cause destructive impact on the built environment, with significant consequences, including potential loss of lives in highly urbanised residential areas located downstream (Haltas, Elçi, and Tayfur 2016). With this in focus, Takagi et al (2016) investigated the potential consequences of a dam-break tsunami-type flooding, induced mainly by land subsidence amongst other environmental factors in Jakarta, Indonesia.…”

Numerical Modeling the Flood and Pollutant Transport Processes in Residential Areas with Different Land Use Types

“…Particularly, the Godunov-type SWEs models have exhibited great potential for modeling transient overland flows and flash floods due to their shock-capturing capability [11]. Some researchers carried out a series of discussions of a hydraulic analysis of the impact of land use on the run-off regime in a retention area and consequently on flood wave propagation [12,13]. e impact of land cover on the propagation of flood waves is important to consider the time and spatial characteristics of the riparian and floodplain areas [14].…”