Mathematical Modeling of the Effect of Meanders Removal on Changes in Erosion Rate: A Case Study in Karun River's Gangieh Meander

One of the nonstructural methods of increasing aqueduct and decreasing flood balance in rivers is to create a shortcut to remove steeped arches. With regard to the dynamic system of river, any type of change in the stable structure of the river may lead to possible changes in the river morphology and creates new problems. In this study, after removing Ganjieh meander in downstream Ahvaz with the aim of organizing and increasing Karun River's aqueduct around Ahvaz city, hydraulic changes of flow and erosion and sediment level after removing meander were modeled using Hec-Ras4 mathematic model. This model was conducted in Karun River in an interval of 16 kilometers around Zargan – Farsiat for 25 years. Results of this research showed that, in the first 16 kilometers, in low to medium discharges of Karun in upstream meander, the water surface balance was high and decreases over time and in high water, discharge does not change significantly over time. In downstream meanders, in medium to high water, discharges, after removing meander water level balance increase compared to conditions before remove. Overall, before and after removing meander, in 16 to 18 kilometer as well as 35 to 40 kilometers, the cumulative weight of erosion and or sedimentation has the maximum value and their density increases over time

Mathematical Modeling of the Effect of Meanders Removal on Changes in Erosion Rate: A Case Study in Karun River's Gangieh Meander

One of the nonstructural methods of increasing aqueduct and decreasing flood balance in rivers is to create a shortcut to remove steeped arches. With regard to the dynamic system of river, any type of change in the stable structure of the river may lead to possible changes in the river morphology and creates new problems. In this study, after removing Ganjieh meander in downstream Ahvaz with the aim of organizing and increasing Karun River's aqueduct around Ahvaz city, hydraulic changes of flow and erosion and sediment level after removing meander were modeled using Hec-Ras4 mathematic model. This model was conducted in Karun River in an interval of 16 kilometers around Zargan – Farsiat for 25 years. Results of this research showed that, in the first 16 kilometers, in low to medium discharges of Karun in upstream meander, the water surface balance was high and decreases over time and in high water, discharge does not change significantly over time. In downstream meanders, in medium to high water, discharges, after removing meander water level balance increase compared to conditions before remove. Overall, before and after removing meander, in 16 to 18 kilometer as well as 35 to 40 kilometers, the cumulative weight of erosion and or sedimentation has the maximum value and their density increases over time

Analysis of the Impact of Removing Meander on Shear Stress and Energy Line Slope by Hec-ras: A Case Study in Krishan Meander of Karun River

Changes and displacements caused by natural or synthetic factors in the track of geometric characteristics of the river is the logical result of river systems' reaction to establishment of a new balance between erosion and deposition process. In this research, the impact of removing Krishan meander on the shear stress and energy line slope of Karun river flow in Ahvaz interval was studied by hec-ras software in two states. In the first state, the current status of Karun river and in the second state Krishan Meander in the downstream of Ahvaz were ignored and shear stress and energy line slope were compared in two states. By comparing two states, it was concluded that ignoring Krishan Meander, average shear stress and energy line slope increased and the increasing level enhanced with the increase of flood discharge. Shear stress increase also reduced the probability of formation of sedimentary hills in city range

Analysis of the Impact of Removing Meander on Shear Stress and Energy Line Slope by Hec-ras: A Case Study in Krishan Meander of Karun River

Changes and displacements caused by natural or synthetic factors in the track of geometric characteristics of the river is the logical result of river systems' reaction to establishment of a new balance between erosion and deposition process. In this research, the impact of removing Krishan meander on the shear stress and energy line slope of Karun river flow in Ahvaz interval was studied by hec-ras software in two states. In the first state, the current status of Karun river and in the second state Krishan Meander in the downstream of Ahvaz were ignored and shear stress and energy line slope were compared in two states. By comparing two states, it was concluded that ignoring Krishan Meander, average shear stress and energy line slope increased and the increasing level enhanced with the increase of flood discharge. Shear stress increase also reduced the probability of formation of sedimentary hills in city range

Evaluating Empirical Equations to Predict Downstream Scour Depth of Jet Ski Overflows: A Case Study in Shahid Abbaspour Dam

Shahid Abbas pour Dam is located at a distance of about 50 kilometers from Masjed Soleiman and a distance of about 150 km North East of Ahwaz. Flood disposal systems and energy dissipation in the construction of a dam are built to prevent flood damage and water depletion in excess of the capacity of dam reservoir. In bucket thrower, water flow reaches the ground bed in front of the structure after passing through the edge of the bucket and the formation of a parabolic curve. Although high-speed flow is associated with energy loss; but due to the collision speed and energy bed erosion and creating a scour hole will be possible. That's why 20 equations were provided to determine Scour depth of the spillway coastal martyr of Shahid Abbas pour Dam; was modeled by Mike software; was coded by Matlab software and was compared with the current situation. The results showed the following equations were introduced as the prior equations to estimate the scour depth in the research range of the present study: 1. National Institute of Science and Technology Laboratory of the French hydraulic; 2-Mason; 3- The organization of study and development of electrical equipment in France. These equations are highly adapted to the existing scour according to local circumstances and information available from the region