Investigating the Effects of Dam Failure in the Downstream Lands Case Study: (Tangab Dam Of Firozabad)

Subject Areas : Natural resources and environmental hazards

ALIREZA غلامیGHOLAMI ¹ , EHSAN SOHRABI SHEKOFTI ²

1 - Assistant Professor, Department of Water, Shiraz Branch, Islamic Azad University, Shiraz, Iran
2 - SHIRAZ

Received: 2023-05-31 Accepted : 2023-08-19 Published : 2023-10-22

Keywords: Tangab Dam, Firozabad River, flood zoning, dam failure, ArcGIS, HEC-RAS,

Abstract :

Introduction: The safety management of dams and structures in the first step requires the evaluation of the actual conditions in the rivers. In Iran, due to being located in a dry and semi-arid climate, special attention has been paid to dam construction in economic development programs. Therefore, it is necessary to consider safety issues and points before building dams. The purpose of this research is to determine the flood trends caused by the dam failure and also the zoning of the flood caused by the failure in the downstream of the dam. Materials and Methods: This research is located in Tangab dam, 13 kilometers northwest of Firozabad city (Kwar-Firoozabad route), which is located on the Firozabad river. This river is the most important branch of Mond river.. In order to carry out this research, firstly, the studies related to the determination of the dam failure parameter, the determination of the failure shape and the time required to create the failure sections, and then the calculations of the flood discharge and the total discharge using 4 experimental methods including Crick-Patrick, America's water and soil protection, reclamation The lands of America, Singh and Storason were done and the results were modeled with HEC-RAS software. Results and Discussion: Based on the results obtained from the estimation of the flood discharge resulting from the dam failure based on the mentioned 4 experimental methods, it was found that the estimated discharge based on the two water and soil protection methods and the creek method was very close (30309 and 30270 cubic meters per second) to So that the difference in this amount is very small. This difference in flood trends and zoning is also very small. The amount of land under flood in both methods is 140 hectares of agricultural lands, 0.5 hectares of industrial lands and 90 hectares of lands in the river area. In the method of Singh and Storason, compared to the other three methods, it shows a lower discharge, according to this method, 133 hectares of agricultural lands are under flood and 84 hectares are in industrial areas. According to this method, industrial lands are not flooded. In the American land reclamation method, compared to the other three methods, it shows a larger discharge equal to 33914 cubic meters per second, as a result of which 161 hectares of agricultural lands, 1 hectare of industrial lands and 100 hectares in the river are flooded. Conclusion: The results of this research showed that the American land reclamation method is better than the other mentioned methods because it has estimated more flow in flood calculation. An important result of flood zoning resulting from the breaking of Tangab dam is that the urban area of Firozabad is safe from this flood and the villages are not flooded as far as the studied area is concerned. Based on the obtained results, it can be concluded that the result of the possible failure of the dam, based on this research, the flood caused by the failure of the dam, except for 1 hectare of the industrial sector, which is a very small area, will cause damage only to agricultural lands.

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