迁安三里河滨水缓冲带雨水径流及污染物消减效果与设计优化

Effects on rainfall runoff and pollutants reduction and design optimization of riparian buffer of Sanli River in Qian′an

滨水缓冲带在入河雨水径流消减及水质净化方面起着关键作用。以迁安三里河滨水缓冲带为研究对象,利用SCS-CN模型、地表径流人工模拟以及水体样品实地采集等方法,揭示了缓冲带的雨水径流消减及水质净化效果,并分析了地表特征对其的影响。研究结果:(1)对雨水径流的消减率可超过80%。前期土壤含水量越低、坡长越长、坡度越小,消减量越大。灌木比草坪、花卉、铺装的消减量大。(2)植被带对TP、TN、NH3-N、COD和SS的消减率可分别达到85.35%、13.41%、68.32%、87.76%和98.5%。径流时长为60 min比30 min的水质净化效果好。草坪、花卉、高草、灌木对污染物的消减率高,砾石的消减率低。坡度从10°降低到5°,消减率可提升50%以上。坡长的增加对净化作用增加不显著。

Riparian buffer has a key function on rainfall runoff reduction and water purification. SCS-CN model, artificial surface runoff modelling, and water sampling were used to reveal the effects on rainfall runoff reduction and water purification of the riparian buffer of Sanli River. Moreover, influence of the surface characteristics were analyzed. The results were as follows:(1) Rainfall runoff could be reduced significantly and the reduction ratio could be more than 80%. Low antecedent soil moisture, long slope length, and low slope gradient could promote the reduction effect. The reduction effect of bush was larger than that of herb, flower, and pavement.(2) The reduction ratio of vegetation on TP, TN, NH3-N, COD, and SS could be 85.35%, 13.41%, 68.32%, 87.76%, and 98.5%, respectively. In general, the water purification effect of 60 min was better than that of 30 min. Herb, flower, high grass and bush had large reduction ratio, while gravel had small reduction ratio. The reduction ratio could be promoted by over 50%, when the slope gradient was cut down from 10° to 5°. The addition of slope length showed little influence on water purification effect.