水电能源科学

白洋淀是华北地区重要的平原湖泊湿地，其水质状况对区域生态环境具有重要影响。为科学研判白洋淀重点断面水质的时空变化规律及其成因，基于MIKE 21模型构建了水动力-对流扩散模型，模拟白洋淀非汛期化学需氧量(COD)、总磷(TP)的迁移特性和分布规律。结果表明，河道水入淀时，入流流量与断面物质的浓度分担率呈正相关关系，与断面水体的物质浓度呈负相关关系，马棚淀水动力条件受限于入淀量不足，导致水质下降，TP浓度达0.043 mg/L;鸪丁淀区域地形复杂，水动力条件弱化，断面水质对河道入流的响应速度较慢；白沟引河、引黄入冀补淀入流与枣林庄枢纽出流是主淀区水质变化的关键因素。通过调控河道入淀流量与适当出流，可显著提升白洋淀水质。研究结果为优化白洋淀水资源调度与水环境治理提供了技术支持。

Baiyangdian is an important plain lake wetland in North China, and its water quality plays a crucial role in the regional ecological environment. To scientifically assess the temporal and spatial variations of water quality at the key sections of Baiyangdian and identify the underlying causes, this study developed a hydrodynamic-convection-diffusion model based on the MIKE 21. The model was used to simulate the migration characteristics and distribution patterns of chemical oxygen demand(COD) and total phosphorus(TP) during the non-flood season. The results show that during river water inflow, the inflow discharge is positively correlated with the concentration share of substances at the cross-section and negatively correlated with the substance concentration in the water body. The hydrodynamic conditions of Mapengdian are limited due to insufficient inflow, leading to a decline in water quality, with TP concentration reaching 0.043 mg/L. The terrain complexity and weakened hydrodynamic conditions in Gudingdian cause slower responses of water quality to river inflows. In the main Baiyangdian area, the inflow from Bai Gou Canal and the Yellow River Water Diversion Project, as well as the outflow from Zaolinzhuang Hub, are key factors affecting water quality variations. By regulating river inflow discharge and maintaining an appropriate outflow, significant improvements in water quality can be achieved. This study provides technical support for optimizing water resource management and water environment governance in Baiyangdian.