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Incorporating Habitat Requirements of the Life Cycle of Salmo trutta into the Estimation of the Ecological Flow Regime of Karaj River
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Mohammad Hasan Naderi *   , Meysam Salarijazi , Hamed Shabanloo |
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Abstract: (195 Views) |
Maintaining a suitable flow in a river is a prerequisite for ensuring the survival of aquatic organisms. In this study, to estimate ecological water requirement of the Karaj River, the method of hydrodynamic simulation habitat suitability (River2D model) in order to investigate the characteristics and habitat requirements of 84 salmo trutta species sampled in 10 studied stations by analyzing the effect of water depth variables, flow velocity and the substrate index was used by collecting data and based on field studies and observations during of the years 2017-2021. Then, habitat suitability curves were used for definition water depth and flow velocity suitable and definition weighted usable area required for the spawning, fry, juvenile and adult periods of the fish in River2D model. The results showed that the optimal ecological flow velocity salmo trutta fish should be between 0.37 and 1.4 m/s and the ecological optimal water depth should be between 0.4 and 0.8 m in different seasons and parts of the Karaj River. The results of the habitat suitability simulation model showed that when the flow rate is between 8-15 m3/s, the weighted usable area values salmo trutta fish are at a high level in the range of 2600-3000 m2. According to field surveys and the distribution of ecologically suitable flows calculated for 10 studied stations in the Karaj River and relative biological criteria, there are favorable conditions for the life of red spotted salmo trutta of the viewpoint hydraulic-ecological parameters in the upstream areas of the Karaj River, while the abundance of salmo trutta fish has decreased due to the lack of ecologically suitable flow in the middle and downstream areas this river. Also, based on the output results of the River2D model, the optimal ecological flow range for the ecological protection of the Karaj river habitat should be considered for carrying out biological activities and the survival of fish species in the spawning, fry, juvenile and adult periods, respectively, is in the range of 6.83-9.74, 3.67-6.93, 4.82-8.72 and 8.26-11.83 m3/s. The present study obtains this important result that the calculated values were particularly accurate, because the ecological flow thresholds estimated by the habitat simulation method were sensitive to the changes in the Suitability curves. By providing the appropriate water depth and flow speed, the ecological needs of the red spotted salmo trutta species in the Karaj River are provided during biological activities, and from this point of view, ecohydrodynamic modeling of the habitat can play an important and prominent role in the ecosystem management of the river flow.
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| Keywords: Ecohydraulic Modeling, Ecological Requirement, Habitat Suitability, Hydrological Regime, Karaj River, Weighted Usable Area |
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Full-Text [PDF 1316 kb]
(39 Downloads)
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Type of Study: Research |
Subject:
Special
Received: 2023/04/10 | Accepted: 2024/01/24 | Published: 2024/09/22
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