【摘要】 入河系数的准确测算对于厘清农业面源污染物对水环境质量的影响具有重要的现实意义。目前,我国入河系数测算仅限于局部流域,未能覆盖全国各个典型流域。由于农业面源污染物传输过程的空间异质性强,不宜简单地将少量的小尺度精细化模拟或实测结果向大尺度区域或全国推广运用。本研究通过对国内外相关研究进行整理综述,可知采用"传输过程类型相似性外推"方法,以数值模拟为主,辅以必要的实地监测验证的技术方案开展全国尺度的入河系数测算工作,能够在一定程度上满足便捷、科学、准确计算全国尺度农业面源污染物入河系数的总体要求。主要包括以下三方面:(1)选取影响农业面源污染物陆面传输过程的降雨、地形、地表径流、地下蓄渗/地下径流以及植物截留五类关键因子对全国流域基本测算单元进行分区分类,运用规范的空间抽样方法,在每个类型区内选取适量"嵌套式"典型流域基本测算单元,作为其测算结果由小尺度流域向大尺度流域扩展,进而向全国范围内具有地带相似性的区域推广;(2)通过评估、筛选、集成已有相关参数测定成果,典型流域基本测算单元模型测算,必要的补充性、校验性的实地监测等多种方法,建立可视化的全国流域基本测算单元入河系数参数库;(3)运用GIS手段和水系网络分析方法将流域尺度获取的入河系数,与县域行政单元进行空间匹配,获取全国县域尺度的农业面源污染物入河系数。更多还原

【Abstract】 Affected by the retention of land use,natural degradation of water bodies and soil properties,the pollution load of agricultural source pollutants that enter into the water bodies is not equal to the pollution load that produced from sources.Therefore,it is more important to clarify the impact of diffuse pollution for water quality.Due to the spatial heterogeneity of the agricultural diffuse pollutants transmission process,it is difficult to make an up-scaling of the parameters from the plot scale to larger watershed scale. In order to meet the requirements of convenient,scientific and accurate for the assessment of the pass through rate of agricultural diffuse sources pollution(PTRADSP) in national scale,we reviewed the current research pertaining to assessment of diffuse pollution load,the results show that the calculation of the Pass Through Rate of Agricultural Sources Pollution in China is limited to local watersheds and fails to cover all typical river basins in the national scale.Therefore,it is recommended to adopt the "parameter up-scaling model based on the discipline of transportation of pollutants in the watershed scale"(PUSM-DTPWS),mainly based on a series of empirical models,supplemented by the necessary in field monitoring and make a verification to key parameters.The major aspects includes that:(1) selecting the five key factors that affecting the land surface transport process of agricultural source pollutants,such as rainfall,topography,surface runoff,underground seepage/underflow,and plant retention,to partition the typical small watershed.Using the normative spatial sampling method,select the appropriate amount of "nested" typical small watershed in each sub-region,as its calculation result up-scaling from plot scale to large-scale watershed,and then has a similarity to the whole country.(2) Establishing a visualized database of PTRADSP for national scale through evaluating,screening,and integrating existing relevant parameter measurement results and the results required in field monitoring;(3) to make a change of PTRADSP from watershed scale to the county unit at the national scale based on the GIS platform and the hydrology analysis method.更多还原