鄱阳湖流域面源污染负荷模拟与氮和磷时空分布特征

基于气象、土壤、土地利用、数字高程模型和农业管理等数据基础上,对输入鄱阳湖赣江、抚河、信江、饶河、修水等"五河"上的7个水文站的径流、泥沙和面源氮(N)和磷(P)污染负荷进行参数的敏感性分析,利用实测数据对参数校准和验证,通过SWAT模型对2003—2012年十年间入湖的径流、泥沙和面源N、P污染负荷进行了模拟.2003—2012年面源总氮(TN)、总磷(TP)、硝氮(NO-3-N)、有机氮(ON)和有机磷(OP)面源污染负荷入湖特征呈现出:时间变化上,年际间变化大、年内集中在4—7月入湖,鄱阳湖N、P污染负荷主要来自于面源污染,入湖面源TN组份中NO-3-N所占比重较高,TP组份中OP所占比重较高的特征;空间分布上,"五河"中赣江流量和流域面积最大,流域各项面源N、P污染物入湖量最大;修水流量和流域面积最小,流域各项面源N、P污染物入湖量最小的特征.

Temporal and spatial distribution characteristics of nitrogen and phosphorus and diffuse source pollution load simulation of Poyang Lake Basin

Based on weather, soil, land use, digital elevation models and agricultural management data, the sensitivity analysis were conducted for the parameters including the runoff, silt and diffuse source nitrogen(N) and phosphorus(P) pollution loading of seven hydrological stations along the "Five Rivers" (including Ganjiang River, Fuhe River, Xinjiang River, Raohe River and Xiushui River) that running into Poyang Lake. The parameters were then calibrated and validated with the measured data and were simulated by using SWAT model from 2003 to 2012. There are large temporal and spatial variations for the characteristics of pollution load, including total nitrogen(TP), total phosphorus(TP), nitrate nitrogen(NO₃^--N), organic nitrogen(ON) and organic phosphorus(OP), from the diffuse source runninginto the lake during 2003 to 2012 . In a year, nitrogen(N) and phosphorus(P) discharged into the lake mainly from diffuse source between April and July. NO₃^--N and OP accounted for the majortiy of TN and TP, respectively. As for spatial distribution characteristics, the flow rate and basin area of Ganjiang River were the largest among the "Five Rivers". Besides, the amount of N and P pollutants into the lake was also the largest from diffuse source. In contrast, these parameters of Xiushui River were the minimum among the "Five Rivers".