基于 GWLF 模型的于桥水库入库河流水文模拟及氮磷负荷估算

Hydrological Simulation and Nitrogen and Phosphorus Load Estimation of Inflow Rivers to Yuqiao Reservoir Based on GWLF Model

流域模型技术应用是当前开展面源污染防治的重要工具,而水文过程的准确模拟是进行污染负荷估算的首要环节和关键步骤。为了弄清近年来于桥水库入库河流氮、磷输入负荷,选取GWLF模型对水平口子流域的水文过程进行模拟,首先利用2006—2018年气象、水文资料率定模型水文参数,然后将参数推广到整个流域,对2019—2020年3条主要入库河流流量进行模拟,最后乘以相应河流断面的总氮、总磷浓度估算氮磷输入负荷。结果显示:GWLF模型适用于研究区的水文过程模拟,校准期和验证期的纳氏系数分别为0.89和0.91,平均相对误差分别为12.2%和13.1%;2020年总氮入库负荷为3977.0 t,其中引滦调水贡献占57.0%,3条入库河流共贡献43.0%;总磷入库负荷为48.8 t,其中引滦调水贡献占68.6%,3条入库河流共贡献31.4%。GWLF模型输入数据需求量较少,模型参数较少,模拟效果较好,适用于中小型流域的水资源和水环境管理,具有一定的推广应用前景。

At present,the application of watershed model technology is an important tool for non-point source pollution prevention and control,and the accurate simulation of hydrological process is the primary link and critical step for pollutant load estimation.In order to figure out the total nitrogen(TN)and total phosphorus(TP)load of inflow rivers to Yuqiao Reservoir in recent years,GWLF model was used to simulate the hydrologic process of the Shuipinkou subbasin.Firstly,the hydrological parameters of the model were determined by meteorological and hydrological data from 2006 to 2018.Secondly,the hydrological parameters were extended to the whole basin,and the flow of three main inflow rivers to Yuqiao Reservoir from 2019 to 2020 were simulated,respectively.Lastly,the nutrient loads were estimated by multiplying the simulated inflow as mentioned above by the observed total TN and total TP concentration data at the same site.The results showed that GWLF model was fit for the hydrologic process simulation of Yuqiao Reservoir watershed.The Nash efficiency coefficients of the calibration period and the validation period were 0.89 and 0.91 respectively,and the mean relative error were 12.2%and 13.1%respectively.In 2020,the TN load of inflow rivers was 3977.0 t,of which 57.0%was contributed by the water diversion from Luan River,and 43.0%was contributed by the three main inflow rivers.The TP load of inflow rivers was 48.8 t,of which 68.6%was contributed by the water diversion from Luan River,and 31.4%was contributed by the three main inflow rivers.GWLF model was suitable for the management of water resources and water environment in small and medium-sized basins,because of its less data demand,fewer model parameters,and better simulation effect,which had a certain prospect of popularization and application.