Almost at the same time, Fread published the numerical models BREACH and Dam Break Forecasting model (DAMBRK), which allowed the simulation of a dam breach via both overtopping and internal erosion, including the effect of lateral slope due to a landslide. Nogueria subsequently presented a 1D model using Saint–Venant’s equations to describe unsteady flow and Exner’s, Meyer–Peter, and Muller’s formula for sediment transport. The model used continuity equations, sediment transport equations, and equations for the formation of the dam breach opening via surface erosion. The surface erosion proceeding on the downstream slope was modeled. Subsequent authors improved the model by specifying the place of origin, simulating the erosion at the lowest point of the dam crest. In the early eighties, the BRDAM model was used to simulate the erosion of an earth dam in the case of overtopping or internal erosion. In the 1970s, Cristofano collected data from historical failures of earth-fill dams occurring up to 1965, based on which he performed a simulation of the onset of erosion. Numerous authors have dealt with the issue of dam breach modeling. 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%. 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 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. The dam-break flood routing was simulated using a shallow water flow hydraulic model. 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. 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. Failures of small dams can pose a serious threat to people and property even if the size of the schemes is relatively low.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |