平原河网河道结构与水体自净能力关系实验研究

文章利用模拟实验开展了平原地区缓流河道中的水质变化对河道水流速度与来水水质的响应规律研究。结果显示,当流速<0.5m/h时,河道中的各种污染物主要以沉积过程为主。当流速在0.5～1.5m/h时,水体最易受外界有机物输入的影响,容易引起局部水质的恶化。当流速>1.5m/h时,水动力条件有利于河道中的有机物的降解,但促进了底泥磷的释放,并会导致下游河道营养盐的升高。所以在河道改造、城市生态河网建设与管理中,应从区域河网整体着手,也应注意缓流河道中来水水质的管理。

Relationship between River Structure of Plain River Net and Water Purification Capacity

Experiment was made to simulate slow flow riverway of plain at the aim to find effect of water quality on current velocity and quality of input water. Results showed that when current velocity below 0.5m/h, contamination in river was mainly in the form of deposit. When current velocity between 0.5~1.5m/h, water body was most vulnerable by external organic matters and quality of local water deteriorated easily. When current velocity exceeds 1.5m/h, the hydrodynamic condition was propitious to the degradation of organic matters, but it promoted the release of phosphorus of sediment from the bottom of river and cause rise of nutrient salts in downstream river. Whole regional river net should be considered and input water quality should be managed in river alteration, construction and management of urban ecotypic river net.