针对平原型水库热分层特征及其对水质的影响问题，采用CE-QUAL-W2模型建立了立面二维水温模型，模拟了2018年全年的水温变化特征，三个率定断面的绝对平均误差分别为0. 53 C、0. 35 C和0.14 °C。基于模拟结果和监测数据，分析了水库热分层的季节性变化及水质响应特征。在轴流泵混合曝气技术的基础上提出了一种移动式扬水器用以增加水库底层DO浓度，基于监测数据初步分析了移动式扬水器对垂向水质的改善效果。结果表明:水库全年呈现单循环混合模式（5月一11月为分层期,12月一4月为混合期），夏季形成稳定的热分层结构，底层形成厚度约为8 m的缺氧区（DO浓度低于2 mg/L）；厌氧环境下底层污染物（铁、镒、总氮、总磷、COD、氨氮等）的释放量远大于表层和中层，底层水质较差;移动式扬水器能够有效提高底层DO含量，弱化热分层结构（工作中心的 DO浓度由0. 2 mg/L提高至0. 8 mg/L,温跃层厚度减少了 4 m）。

Aiming at the thermal stratification characteristics of plain reservoirs and their impact on water quality, a vertical two- dimensional water temperature model was developed using the CE-QUAL-W2 model to simulate the characteristics of water temperature changes throughout 2018. The absolute mean error of the three calibration sections was 0. 53 °C, 0. 35 °C and 0. 14 °C respectively. The seasonal variation of water temperature and water quality response characteristics of the reservoir were analyzed based on simulation results and monitoring dat& A mobile water pump was proposed based on the axial flow pump mixed aeration technology to increase the DO concentration in the bottom of the reservoir. The improvement effects of the mobile water pump on vertical water quality were preliminarily analyzed based on the monitoring data. The results showed that the reservoir presented a singlocycle mixed mode throughout the year (stratified period: May to November, mixed period: December to April). The reservoir formed a stable thermal stratification structure in summer and formed a hypolimnion with a thickness of a- bout 8 m anoxic zone (DO concentration is less than 2 mg/L). The release amount of pollutants (iron, manganese , total nitrogen, total phosphorus, COD, ammonia nitrogen, and so on) in hypolimnion was much larger than the epilimnion and the thermocline because of the anaerobic environment. The mobile water pump can effectively improve DO concentration in the hypolimnion and weaken the thermal stratification structure (the DO concentration in the working center increased from 0. 2 mg/L to 0. 8 mg/L,and the thermocline thickness decreased by 4 m).

国家重点研发计划(2016YFC0401700；2018YFC0407702)；国家水专项(2017ZX07101004-001);中国水科院团队建设及人才培养重点项目(WE0145B592017)；国家自然科学基金(51809288)