云南某大型水库及其灌区水温影响研究

Study on the Impact of Water Temperature of a Large Reservoir and Its Irrigation Area in Yunnan Province

云南某大型水库为季调节水库。采用宽度平均的立面二维水温数学模型对典型平水年的水库水温分布、下泄水温及其灌溉干渠沿程水温进行了预测和分析,结果表明:该水库水温结构呈过渡型水温结构和季节性水温分层现象,其中2—5月存在表层温跃层,分层现象较明显,垂向最大温差3.3℃。水库运行对下游水温过程有一定程度的春夏季低温水影响。下泄水温在2—7月比建坝前坝址水温有所降低,最大温降达2.3℃,年均下泄水温比建坝前降低0.2℃。经分析,水稻生长各期的灌溉水温均在水稻正常水温承受范围内,水稻正常生长不受影响。

A large reservoir in Yunnan is a seasonal regulation reservoir.The distribution of reservoir water temperature and the discharge water temperature and the water temperature along the main irrigation canal in typical normal year were analyzed and predicted using the vertical two-dimensional water temperature mathematical model with average width.The water temperature structure of the reservoir presented transitional water temperature structure and seasonal water temperature stratification phenomenon.The surface thermocline existed from February to May,and the stratification phenomenon was obvious.The maximum vertical temperature difference was 3.3℃.The operation of the reservoir has a certain impact on the downstream water temperature process,such as low-temperature water in spring and summer.The maximum temperature drop is 2.3℃and the average annual discharge water temperature is 0.2℃,which is lower than the time before the dam was constructed.The analysis showed that the irrigation water temperature in each growth stage of rice was within the normal water temperature range,and the normal growth of rice has not been affected.The research results would provide technical reference for related environmental management.