基于MIKE21数值模拟的滆湖换水能力评估分析研究

Evaluation and Analysis of Water Exchange Capacity of Gehu Lake Based on MIKE21 Numerical Simulation

摘要: 湖泊换水能力直接影响着污染物迁移和水体自净能力，为探究不同引水流量入湖对滆湖换水能力的影响，文中使用MIKE21建立了滆湖水动力水质模型，模拟并对比分析多种工况及工况组合对湖区整体和局部的水体交换能力的影响；提出了使用水体更新时间和水体交换率两个指标，定量分析交叉验证水体交换能力。结果表明：引水流量为100、150、200、250 m³/s时整个湖泊水体交换率到达80%以上分别需要60 d、45 d、32 d、30 d。本文的网格划分方案为湖泊水动力水质模型建模提供了新思路，换水能力两个指标能够从时间和空间上综合全面的评估湖泊换水能力，研究成果可为滆湖水质改善工程提供重要科学参考。

Abstract: The water exchange capacity of lakes directly affects the migration of pollutants and the self-purification capacity of water bodies. To explore the influence of different water diversion flows on the water exchange capacity of the lake, MIKE21 was used to establish a hydrodynamic water quality model of the lake, and the influence of various combinations of working conditions on the overall and local water exchange ca-pacity of the lake area was simulated and compared. The quantitative analysis of water renewal time and water exchange rate was proposed to cross-verify the water exchange capacity. Considering the invest-ment amount and effect, the results show that when the water diversion flow is 100, 150, 200 and 250 m³/s, the water exchange rate reaches over 80% of the whole lake needs 60 d, 45 d, 32 d and 30 d, respec-tively. The meshing scheme provides a new idea for the modeling of lake hydrodynamic water quality model, and the dual indicators of water exchange capacity can comprehensively evaluate the lake water change capacity both from time and space, which can provide an important scientific reference for the wa-ter quality improvement project of Gehu Lake.