石马河泄洪与东江水利枢纽调节不同情景下东江水质的模拟与分析

摘要

In this study,a two-dimensional water dynamic and water quality model based on MIKE21 was developed to simulate the water quality at the intake of Dongshen water supply project.The study was carried out in the tidal reach between the Dongjiang Hydro-Project and Shilong in the downstream of the Dongjiang River,and NH3-N was taken as the water quality indicator.Different scenarios of flood dis-charge from the Shima River and the release discharge of the Dongjiang Hydro-Project were used to drive the model for the simulation of the water quality at the intake of the Dongshen water supply project.The results indicate that:① the change of the NH3-N concentration at the intake is related to the tidal change,the NH3-N concentration over-standard occurs during higher high water level period;② flood tide is the main factor which impacts the water quality at the intake,and the NH3-N concentration is more than 0.5mg/L during higher high water lever period;③ more flood discharge from Shima River has the greater effect on the water quality,and the water regulation of the Dongjiang Hydro-Project can cause a significant improvement on water quality in the downstream.The results of this study contribute to the de-cision-making for the joint operation of the flood discharge from Shima River and the intake of Dongshen water supply project,also have great significance for the emergency operation of the Dongjiang Hydro-Project.%以东江干流下游东江水利枢纽～石龙河段为研究范围，构建基于 MIKE21的二维感潮河段水动力、水质模型，以氨氮为水质控制因子，模拟分析汛期石马河泄洪排污及东江水利枢纽不同水量调节情景下，东深供水工程东江取水口水质变化规律，结果表明：①受潮流影响，石马河各种泄洪流量情景下取水口氨氮浓度变化与潮位变化关系密切，显示出较为明显的大小潮变化的周期性；②涨潮过程是影响取水口水质的主要控制因素，氨氮浓度超标均发生在高高潮时；③石马河泄洪量愈大对东江水质影响愈大，东江水利枢纽水量调节对下游水质有明显的改善作用。结果可为汛期石马河橡胶坝与东深供水工程取水口联合调度及东江水利枢纽应急水量调度提供决策依据。