密云水库上游流域水体营养物质季节变化特征分析

Seasonal Variation of Nutrients in Rivers of the Upper-river Basin of Miyun Reservoir

通过密云水库上游不同尺度流域水体营养物质监测,了解水体营养物质季节变化特征,分析不同径流和泥沙条件对水体营养物质运移的影响。结果表明:各类水体营养物质季节变化幅度为TP>CODMn>NH4+-N>TN>NO3--N。流量和径流含沙量是影响河流水体营养物质浓度季节变化的重要因素。河流水体CODMn浓度与流量呈显著正相关,水体TP浓度与含沙量、流量均呈显著正相关;但在河道径流量较大时,TP和CODMn浓度随流量增大而递增速率明显小于径流量较小时。水体TN、NO3--N和NH4+-N浓度与流量或含沙量均无显著相关关系。

To address adequately the management for nutrient load reduction in the upper-river basin of Miyun reservoir, water samples, collected from river basins at different scales, were analyzed for total nitrogen（TN）, nitrate（NO3--N）, ammonium（NH4＋ --N）, total phosphorus（TP） and permanganate index of chemical oxygen demand（CODMn） to illustrate seasonal variations of nutrients. The factors that influenced seasonal variation of nutrients were analyzed. The results showed that the range of seasonal variation of the nutrients were： TP〉CODMn〉NH4＋-N〉TN ~N03--N. In each basin, the concentration of TP and COI）Mnincreased with increasing river flow. However, when river flow was high, the increasing tendency of the eoncentration of TP and CODMn were not obvious when the river flow was low. The concentration of TP also increased with increasing suspended sediment. In addition, Variation of river flow didn＇t have significant effect on seasonal change of the concentration of TN, NO3-N or NH4＋ -N, nor did variation of suspended sediment.