黄旗海湿地水量模拟与平衡分析

Simulation of Water Inflow and Water Balance of Huangqihai Lake Wetland

黄旗海湿地是华北地区重要的生态安全屏障,湿地所处的黄旗海盆地属于农牧交错区和多民族聚居区,生态十分脆弱。通过分析湿地退化原因,提出了平原区深层地下水过量开采是黄旗海湖水干枯的直接原因。建立了湿地湖水水量平衡分析模型,模拟不同降水和规划条件下入湖水量组成及其变化。分析表明:丰、平、枯水年份可以维持的平均水面面积分别为29.83 km^2、31.67 km^2和23.79 km^2;最大水面出现在年底,湖泊未来水文情势不同于历史时期,因地表来水呈减少趋势,湖水面的维持将越来越依赖地下水。2020年和2030年生态修复可维持湖水面面积目标分别为20 km^2和30 km^2。研究成果可为黄旗海流域水资源开发与水生态保护规划提供科学依据。

As an important ecological security barrier of north China,the Huangqihai Lake wetland is a farmingpastoral ecotone with extremely fragile ecological environment. The wetland suffers from the serious degradation caused mainly by the irrational exploitation of water and land resources as well as the drying of climate change during recent decades. In this paper,the main causes of wetland degradation were discussed,and it was considered that the lake drying-up was directly caused by the over-pumping of groundwater from the confined aquifers in the basin. The lake water balance model was developed to simulate the interaction of surface water and groundwater by using the numerical groundwater flow model. The inflows of the lake were calculated,and the results revealed that the water areas in normal,high-flow and low-flow years were 29. 83 km2,31. 67 km2 and 23. 79 km2 respectively.The results of monthly water balance illustrated that the largest water area occurred in December instead of rain season,this was quite different from the previous hydrological results of the lake. The sustainable water areas of the lake for regenerating the ecology in the future were determined based on analyzing the hydrological regime,and they would be 20 km2 and 30 km2 in 2020 and 2030 respectively. The research results could be referred in planning the water resources exploitation and conserving the wetland in the basin.