**Extended Abstract**

**Introduction and Objective:** Dam failure and release of stored water behind the dam is one of the most important issues in dam design and it is necessary to pay attention to its occurrence and consequences. Therefore, policymakers and planners are obliged to take measures to prevent the possible dangers of breaking the dams. Among these measures, we can mention the creation of a retaining wall in the path of flood flow due to the failure of dams.

**Material and Methods:** In the present study, the construction of a retaining wall in the flood flow path due to the failure of the Ghare Aghach earth dam at different distances and scenarios has been investigated. Parameters due to dam failure were determined using the BREACH model and then its information was entered into HEC-RAS software.

**Results:** If the hole is created at the level of 2451 meters from the body, 18 of the 50 sections examined will collide from the right bank or the left bank, or both. At a distance of 300 meters from the dam, the water flow at a height of 1.74 meters from the right and the water flow at a height of 2.55 meters from the left shore collide. At a distance of 2200 meters from the dam, the water flows at a height of 5.15 meters from the right bank and at a height of 0.51 meters from the left bank. At a distance of 3,000 meters from the river, water rises to a height of 3.39 meters from the left side. At 3100 meters from the dam, the water flows to a height of 2.68 meters from the left bank. At a distance of 4400 meters from the river, water at a height of 1.19 meters from the right bank collides. Finally, section 4700 of the water river attacks at a height of 3.48 meters from the right bank. However, if a hole is created at the level of 2446 meters from the body of the dam, 15 of the 50 sections examined will be attacked from the right or the left bank, or both. Therefore, in this case, at a distance of 300 meters from the dam, water flows to a height of 0.8 meters from the right bank and also water flows to a height of 2.21 meters from the left bank. At a distance of 2200 meters from the dam, water flows at a height of 4.21 meters from the right shore. At a distance of 3000 meters from the dam, the water flow at a height of 2.86 meters from the left bank. At 3100 meters from the dam, water flows at a height of 2.23 meters from the left bank. At a distance of 4400 meters from the river, water at a height of 0.9 meters from the right bank collides. Finally, at a distance of 4700 meters from the location of the dam, the water flow at a height of 2.97 meters from the right shore collides.

**Conclusion:** Areas with higher probability of flooding and with priority to the construction of a retaining wall were identified. The failure of the dam at level 2451 compared to level 2446 will cause flooding of more sections on the sides of Mehrgerd river. Among the sections studied, the most water flows attack at a distance of 2200 meters and is related to the time when a hole is created at the level of 2451 meters from the body of the dam, which due to its critical location is more important than other sections and the need to construct The wall is a barrier.

Type of Study:

Research |
Subject:

Special Received: 2022/04/24 | Accepted: 2022/06/6