外调补水条件下流速对景观水体水华抑制效果模拟研究

SIMULATION OF WATER BLOOM CONTROL EFFECT OF LANDSCAPE SLOW-MOVING WATER BODIES BY VELOCITY UNDER ECOLOGICAL WATER REPLENISHMENT

城市景观缓滞水体水华控制及水力条件改善是当前城市湖泊、河流等景观水体生态健康恢复的关键问题。永定河生态补水措施用于缓解莲石湖8号湖等景观缓滞水体面临的水华易发问题,然而该补水过程对景观水体的水华控制成效尚不明确。基于2019—2021年水质、水文、藻类实测数据,通过构建莲石湖8号湖水动力-水质二维耦合数值模型,结合现场监测数据对耦合数值模型进行率定与验证,探讨了在不同补水条件下8号湖叶绿素a含量和缓流区域的变化特征,定量分析了不同外调补水条件下缓滞区空间分布、叶绿素a浓度与典型景观缓滞水体水文条件的响应关系。结果表明:不同外调补水流量能够有效控制缓滞水体内叶绿素a含量,当外调补水流量为0.23~0.96 m^(3)/s时,莲石湖8号湖表层水体中叶绿素a浓度较低且缓流区域面积较小。该研究结果可为城市景观水体水华控制及外调补水优化方案的制定提供技术支撑。

The control of water bloom and the improvement of hydraulic conditions have become the key problems of ecological health restoration of urban lakes and rivers.The ecological water replenishment measures of Yongding River can alleviate the prone problem of water bloom in landscape slow-moving water bodies,including Lianshi No.8 lake.However,the effect of the water replenishment process on water bloom control of landscape water bodies is not clear.Based on the data of water quality,hydrology and algae from 2019 to 2021,the two-dimensional coupling numerical model of hydrodynamic water quality of Lianshi Lake No.8 Lake was constructed to study the variation characteristics of chlorophyll-a content and slow flow area of Lianshi No.8 Lake under different replenishment conditions.When the external water refill flow was within the range of 0.23 to 0.96 m^(3)/s,the concentration of chlorophyll-a in the surface water of Lianshi Lake No.8 Lake was lower,and the slow flow area was small.This study can provide data support for the research of urban landscape water bloom control and formulation of water replenishment optimization schemes.