广州城市河流形态对河流自净能力的影响

Impact of river morphology on urban river self-purification capacity in Guangzhou

构建了包括河道分维数、河道断面形态、河岸基质、河岸带宽度、河岸带植被盖度、河床底质状况、河床栖境复杂性共7项指标的城市河流形态评价体系,并以乌涌广州市开发区段为研究对象,通过定期水质监测研究河流形态对河流自净能力的影响。结果表明,该评价体系能够反映研究河段的形态差异;不同形态河段水体BOD5降解系数及多项水质指标沿程降解率均有显著性差异;河流形态评价得分较高的河段水体自净能力也较强;河流形态与NH3-N、SS、DO和浊度的降解存在相关性,是影响河流自净能力的重要因素。

A river morphology assessment system with seven indexes,channel fractal dimension,channel sectional morphology,riverbank substrate,riparian width, riparian vegetation coverage,riverbed material,and riverbed habitat complexity,was constructed and used to study the effect of river morphology on the river self-purification capacity of Wuyong Stream in Guangzhou through regular water quality monitoring.The results showed that this system can reflect the morphology differences among the reaches.The BOD5 degradation coefficient and alongpath degradation rate of several water quality indexes in different reaches showed significant differences.The reach with the higher river morphology index value had a better self-purification capacity.River morphology had a correlation with the degradation of NH4^＋-N,SS,DO,and turbidity,which was an important factor for river self-purification.