渭河关中段典型支流非点源污染监测与负荷估算

2009年，对渭河关中段3条典型支流泾河、沣河和灞河进行了洪水期和非洪水期水质水量同步监测，水质监测指标包括COD、DP、TP、NH4+-N和TN.根据监测结果及水文站实测流量资料，分别采用水文分割法和平均浓度法对各条支流的非点源污染负荷进行了计算，分析了非点源污染的特点.结果表明：①3条河流洪水期间各指标的平均浓度基...

Monitoring and load estimation of non-point source pollution on typical tributaries in the Guanzhong reach of the Weihe River

The water quality of the Weihe River is heavily affected by non-point source pollution (NSP) from its tributaries. To quantify NSP loading from its major tributaries we monitored both water flow and water quality of three tributaries, Jinghe River, Fenghe River and Bahe River, in the Guanzhong reach of the Weihe River during the flooding and non-flooding periods in 2009. Measured water quality factors included COD, dissolved orthophosphate, TP, NH₄⁺-N and TN. NSP loadings were computed using two methods: hydrological division and mean concentration. The results indicate that: 1the mean concentrations were higher during the flooding period than during non-flooding periods.2The peak pollutant concentrations occurred either before or at the same time as the flow peaks; the peak load transport rates appeared at the same time as the flooding peaks, which was in accordance with the natural process of initial ground surface flushing; the variations of pollutant concentrations were smaller during the non-flooding periods than during the flooding periods, and bigger floods had smaller variations in pollutants concentrations than smaller floods;3 The results using the hydrological division method were in good agreement with the well tested and widely used mean concentration method, and this indicated that the hydrological division method can be used to estimate NSP loading when limited data is available. The mean values from both methods showed that NSP accounts for a significant proportion of pollution for the three rivers, which cannot be ignored.4In terms of annual pollutant loading, most of it occurred during the flooding periods.5NSP accounts for a majority of the total annual pollutant loading, i.e., 43% of the COD, 75% of the dissolved orthophosphate, 83% of the TP, 64% of the NH₄⁺-N and 47% of the TN.