A FLOOD RISK ASSESSMENT BASED ON DAM-BREAK FAILURE: CASE STUDY ON ONDOKUZ MAYIS DAM

Date

2025-1-10

Author

Palamut Kemaloğlu, Nazlı

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

21
views

8
downloads

Cite This

This study focuses on the flood risk assessment of a hypothetical two-dimensional failure of the Ondokuz Mayıs Dam, a clay core rockfill dam type located in Samsun, Turkey, with a height of 89.75 meters. The main objective is to evaluate flood risks under different dam failure scenarios and estimate the economic damages. The study compares the effects of model mesh sizes, breach parameter prediction equations, and hydraulic solution methods, including shallow water and diffusion wave approaches, on flood analysis results. To improve the accuracy and reliability of the analysis, all structures within the floodplain were modeled in 3D and integrated into the DEM model. The breach hydrographs were routed over the floodplain using HEC-RAS, and the results were visualized using ArcGIS software. Missing precipitation and flow data after 2010 were obtained from the DSI and used to recalculate dam operation studies and project flood discharges. The adequacy of the current spillway capacity was checked, dam slope safety factors under different loading conditions were determined, and the dam's safety against uplift effects, backward erosion piping risks, and seepage risks from the dam body and foundation were also evaluated. To assess the performance of the current design, the downstream slope's horizontal unit was incrementally increased from 2.0H:1.0V to 2.6H:1.0V at 0.1 intervals. Monte Carlo simulations (using Slide2 software) were used to calculate the probabilities of dam failure for each slope, and the long-term economic benefits and cost-benefit ratios of the modified slopes were analyzed to strengthen the design. Finally, flood damage maps for buildings, roads, and agricultural areas were created for the worst-case failure scenarios. Economic losses were similar in both scenarios, with the majority of losses involving buildings and infrastructure (roads).

Subject Keywords

Baraj yıkılması, İki boyutlu taşkın modelleme, HEC-RAS, Taşkın risk değerlendirme, Monte Carlo simülasyonu

URI

https://hdl.handle.net/11511/113742

Collections

Graduate School of Natural and Applied Sciences, Thesis