Combined inverse modeling approach and load duration curve method for variable nitrogen total maximum daily load development in an agricultural watershed
Combined inverse modeling approach and load duration curve method for variable nitrogen total maximum daily load development in an agricultural watershed
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DOI：
10.1007/s11356-011-0502-8
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发表时间：
2011-04
影响因子：
5.8
通讯作者：
Dingjiang Chen;Jun Lu;Hailong Wang;Ye-na Shen;Dongqin Gong
中科院分区：
文献类型：
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作者：
Dingjiang Chen;Jun Lu;Hailong Wang;Ye-na Shen;Dongqin Gong
目的非点源 (NPS) 污染是全球水质受损的重要原因。为了考虑NPS污染和河内衰减的时间变化，将逆向建模方法和负荷持续曲线（LDC）方法相结合，用于可变养分总最大日负荷（TMDL）开发。方法2004-2008年对长乐河水系沿线的水质和水文参数进行每月监测。流域 NPS 输出负荷 (EL) 和总氮 (TN) TMDL 通过现有河流养分输送方程的逆格式进行估算。采用LDC方法描述EL、TMDL、所需负荷(RLR)和减少百分比(RLR与EL、RPR之间的比值)的变异性，然后设定不同不确定性下需要减少的变量。结果虽然TN的EL和TMDL均随河流流量增加而增加，但随着河流流量的增加，EL的增量大于TMDL的增量。因此，RLR 也随着水流流量的增加而增加。 TN TMDL 的河内衰减能力的贡献随流量的增加而减小，占整个水系TMDL 的37.3±10.4%。为了确保90%符合目标河内TN水平，不同流态的RLR和RPR分别为1.16 × 103–19.02 × 103kg day−1和53.6–59.9%。结论对于NPS污染主导的流域，TMDL的时间变量表达和要求减少都是必要的。这种组合方法为研究人员和管理人员提供了一种简单但高效的工具来进行可变 TMDL 开发。
PurposeNonpoint sources (NPS) pollution has been an important cause for water quality impairment worldwide. To take the temporal variations of both NPS pollution and in-stream attenuation into consideration, an inverse modeling approach and the load duration curve (LDC) method were combined for variable nutrient total maximum daily load (TMDL) development.MethodsWater quality and hydrological parameters were monitored monthly along the ChangLe River system in 2004–2008. The catchment NPS export load (EL) and TMDL for total nitrogen (TN) were estimated by the inverse format of an existing stream nutrient transport equation. The LDC method was used to describe the variability of EL, TMDL, requiring load (RLR) and percent (the ratio between the RLR and the EL, RPR) reduction, and then to set the variable requiring reductions under different uncertainties.ResultsAlthough both EL and TMDL for TN increased with stream flow, the increments of EL became larger than that of TMDL with increasing stream flow. Thus, RLR also increased with stream flow. The contribution of in-stream attenuation capacity for TN TMDL, which decreased with stream flow, occupied 37.3 ± 10.4% of the TMDL for the entire river system. To assure 90% compliance with the target in-stream TN level, the RLR and RPR was 1.16 × 103–19.02 × 103kg day−1and 53.6–59.9% for different flow regimes, respectively.ConclusionsFor the NPS pollution-dominated watershed, temporal variable expressions of TMDL and requiring reduction are both necessary. This combined approach provides researchers and managers with a simple but efficient tool for variable TMDL development.