城市湖泊随季节变化的生态补水数值模拟研究

Numerical simulation on seasonal ecological water supplement for urban lakes

城市湖泊在社会经济发展中发挥着生态系统服务、防汛、景观等重要功能的同时,其水质受到污水排放、下垫面改变和污染物输入的严重威胁。然而,大多数水生态修复措施未考虑降水、排涝等因素的季节变化特征。提出了考虑年内降水分布规律和城市排涝需求的季节变化生态补水方案。以武汉市龙阳湖为研究对象,通过构建二维水动力水质数学模型,模拟生态补水措施实施后湖泊水质状况,从时间和空间两个维度分析水质目标的可达性,得到生态补水推荐方案。结果表明:在Ⅳ类水质的总体目标下,推荐方案的湖泊水质平均达标面积比例和平均达标天数比例均高于80%,效果较好。研究成果可为城市湖泊的生态补水工程措施提供技术支撑。

Urban lakes play critical roles in socioeconomic development through providing ecosystem services,flood control,and landscape functions.The water quality of the lakes faces severe threats from sewage discharge,underlying surface changes,and pollutant input.However,most of the water ecological restoration measures have not considered the seasonal variation characteristics of factors such as precipitation and drainage.We proposed a seasonal ecological water supplement scheme that considered the variations in the distribution of annual precipitation and drainage demands in different seasons in a city.Taking Longyang Lake in Wuhan City as the study area,a two-dimensional hydrodynamic water quality mathematical model was constructed to simulate the water quality of the lake after the implementation of water ecological supplement measures.The accessibility of water quality targets was analyzed from both temporal and spatial perspectives,and a preferred water ecological supplement scheme was recommended.The study results indicated that under the overall target of Class IV water quality standards,the recommended scheme performed effectively.The average proportions of lake areas and days of water quality meeting standards would both exceed 80%.The results can provide technical support for the implementation of water ecological supplement engineering in urban lakes.