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Approaches and experiences in ephemeral stream flood control and the performance of the floodwater spreading systems on aquifers
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ALIREZA ESLAMI *    , Aliakbar Abbasi |
| Assistant Professor, Khorasan-e-Razavi Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Mashhad, Iran, Email: Ar.eslami@areeo.ac.ir & Kanrrc |
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Abstract: (181 Views) |
| In this research, various methods of floodwater spreading on aquifers (11 plans) and their main components from a practical perspective have been analyzed. Performance of the intake systems showed that in the direct water intake, the problem of sediment entry seriously reduces the efficiency of the intake system. However, if flood control operations are carried out with a diversion dam or an appropriate water Intake structure, the problem of sediments and reduced channel transfer capacity will be reduced to some extent. If the river's suspended sediments are high, sedimentation in streams and spreading areas will result in a decrease in permeability. Therefore, to overcome the problem of sediment load entering the system, it is doubly necessary to pay attention to suitable flood control locations and observe the principles of design and implementation operations, especially where the method of flood control is indirect and through the diversion of a stream from a river. In this regard, in some systems, including the Gonabad and Sabzevar aquifers, Turky-nest structure has been implemented, but due to the high sediment load after several flood events, they have practically lost their effectiveness and require sediment discharge and repair. From the functional aspect of the structures, examples of scours that occurred downstream of the Drops in the Kashmar aquifer and the flow Gates in the Sabzevar aquifer indicate an inappropriate number of Drops and an unsuitable design of the relaxation Stilling pool downstream of the Drops and Gates. If the structures used in FloodWater Spreading System (FWSS) are not designed and implemented suitably, they will be completely or partially destroyed, and the entire performance of the FWSS will be affected. The performance results of the systems showed that in the downstream areas of alluvial fans with micro-channels, the method of flood spreading through the expansion channel and the spreading edge is not adequately efficient. The method of controlling and directing floods in this way causes the flow to concentrate in erosive points, destroying system components and causing the uniformity distribution floodwater. In contrast, in areas with suitable topography, with low terrain slopes and no micro-channels (such as the Jajarm aquifer), systems using the edge of the spread perform successfully. |
Article number: 4 |
| Keywords: Spreading systems, Floodwater, Drop, Aquifer, Floodwater supply Channel |
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Type of Study: Research |
Subject:
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