白洋淀水质改善方案优化及实施效果研究

模拟与分析白洋淀试点区域水质改善工程前后的水质变化情况,探索水质改善效果,为白洋淀水质改善提供思路与经验。基于实测地形、气象数据、水质监测数据、现状污染源、大气沉降、风扰底泥释放等数据资料,运用MIKE软件构建了白洋淀二维水动力和水质数学模型,选取现状水量未清淤(方案一)、增加补水流量1.5倍+未清淤(方案二)、增加补水流量2.0倍+清淤0.1 m(方案三)、增加补水流量2.0倍+清淤0.2 m(方案四)4种优化方案,模拟了典型时刻下白洋淀区域内的流场分布形态和主要污染物迁移扩散规律。结果表明:白洋淀淀区内水体流动速度普遍较小,在增大补水流量和清淤的情况下,流场的改变集中于入淀河流的下游,几乎不改变主淀中的流场分布。随着清淤深度的增大,底泥的污染物释放作用进一步削弱,但削弱的幅度较小。由此确定对白洋淀底泥厚度较大、水质污染较为严重的区域开展清淤工作,建议清淤厚度0.2 m左右。在清淤的基础上,对淀区进行合理补水,入口河流选用常年水质较好的河段,建议补水体积不超过现状补水方案的2倍。

Water Quality Optimization Schemes and Ecological Effect Assessment in Baiyangdian Lake

The aim of the study was to explore the methods to improve the water quality of baiyangdian lake.. Based on the data for the observed terrain, meteorological data, water quality monitoring data, current pollution sources, atmospheric subsidence, wind-disturbed sediment release, etc. MIKE software was used to construct a two-dimensional hydrodynamic and water quality mathematical model of Baiyangdian lake. Four optimization schemes of increasing water replenishment flow and carrying out partial dredging were selected. The results show that: the water flow speed in baiyangdian district is generally low. In the case of increasing water replenishment flow and dredging, The change of flow field was concentrated in the lower reaches of the inflow river, and the distribution of flow field in the main river was hardly changed. With the increase of dredging depth, the pollutant release effect of sediment is further weakened, but the degree of weakening is small. Therefore, it is determined to carry out the dredging work in the areas with large sediment thickness and serious water pollution in baiyangdian lake, and it is suggested that the dredging thickness should be about 0.2m. On the basis of the dredging work, the water should be replenished reasonably in the haidian district. The inlet river should be selected to reach a reach with good water quality all the year round. It is suggested that the volume of water replenishment should not exceed 2 times of the current water replenishment scheme. The research results can provide ideas and experience for the improvement of water quality in baiyangdian lake and have important scientific and engineering significance for the construction of water ecological civilization in xiongan new area.