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| DOI：10.13522/j.cnki.ggps.2022257 |
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| Simulation Study on the Effects of Small and Medium-sized River Flood Control Reservoirs in Mountainous Areas on Water Temperature: A Case Study in Gujun Reservoir |
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LI Jianwei, ZHUANG Chunyi, ZHANG Peng, LIANG Ruifeng
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1. Sichuan Water Resources and Hydroelectric Investigation & Design Institute CO., LTD, Chengdu 610072, China;
2. State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China
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| Abstract: |
| 【Objective】The purpose of this paper is to explore the effect of water temperature in small and medium-sized river flood control reservoirs in mountainous areas.【Method】In this paper, the Gujun reservoir, which is in Jialing River Basin, was selected as the research target. A laterally-averaged water temperature model was developed to simulate the water temperature distribution in the reservoir and water temperature released from reservoir under different scenarios in typical normal, dry and wet years (namely, scenario 1, 2 and 3, respectively). Then, the influence of the reservoir on water temperature, fish migration and spawning in National Aquatic Germplasm Reserves in China were discussed.【Result】The results showed that Gujun reservoir was a seasonal stratified reservoir under all scenarios, and the bottom water temperature was not stable during the whole year. The remolding of reservoir water temperature structures created more suitable water temperature channels for Schizothorax migration in the National Aquatic Germplasm Reserves. In addition, the operation of Gujun reservoir had a significant impact on the water temperature downstream. When reservoir operated without mitigating measures, the spawning start time of Cyprinus carpio and Carassius auratus under scenarios 1, scenarios 2 and scenarios 3 were delayed to the end of April, early May and the last ten days of April respectively, where the influence degree from small to large was scenario 3 < scenario 1 < scenario 2. Moreover, the phenomenon of low temperature water in spring had been effectively alleviated when the reservoir operated with stratified water intake measures at which the negative effects on spawning almost disappeared under scenarios 1 and 3, while the influence degree of low temperature water in scenarios 2 was extremely limited.【Conclusion】The low water level operation of flood control reservoirs in small and medium-sized rivers is conducive to the migration of fish in the reservoir area, meanwhile the front retaining wall can be used to alleviate the low-temperature water discharged to protect fish spawning. The results of this research can provide basic technical support for reservoir managers to implement ecological operation. |
| Key words: flood control reservoir; water temperature; national aquatic germplasm reserves; stratified water intake |
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