摘要
在瑞典南部,为了清除农业流域中的氮而建造了一些湿地。利用3个监测很好的湿地的输入-输出数据也估算了这类湿地对河流中磷的可能影响。这样做是为了设计一个取决于流入特征的磷清除的简单模型。然后,利用HBV-NP模型和有关湿地面积和位置的假设,在流域尺度(1900km^2)模拟了湿地对氮和磷降低的影响。这3块湿地都作为总磷(tot-P)和总悬浮固体物质(TSS)的沉降地,其清除量分别为10%～31%和28%～50%。17～49kg/hm^2·a的平均磷清除率与该模型拟合得非常好。在流域尺度进行的模拟表明,湿地捕获磷要比捕获氮更有效(以负荷的百分比来计算),也表明可能应当鼓励在远离流域排水口的上游建造清除磷的湿地。
In southern Sweden,wetlands are constructed to remove nitrogen (N) in agricultural catchments.The possible effects of such wetlands on riverine phosphorus (P) were also estimated using input-output data from three wellmonitored wetlands.This was done to formulate a simple model for removal of P that is dependent on inflow characteristics. Next,the N- and P-reducing effects of wetlands were modeled on a catchment scale (1900 km^2) using the HBV-NP model and various assumptions about the wetland area and location. All three wetlands functioned as sinks for total P (tot-P) and for total suspended solids (TSS) with a removal of 10% to 31% and 28% to 50%,respectively.Mean P-removal rates of 17-49 kg ha^(-1) yr^(-1) were well simulated with the model.Catchment scale simulations indicated that wetlands were more efficient (in percentage of load) as traps for P than for N and that this may motivate the construction of wetlands for P removal far upstream from the catchment outlet.
