基于农业非点源污染模型的灞河流域径流模拟与分析

摘要

以西安市灞河流域为研究对象,运用农业非点源污染模型(AnnAGNPS)开展径流模拟应用研究.基于马渡王省级监测断面日观测数据,以2002—2003年数据校验模型参数,分别对曲线数(CN 值)、沟道曼宁系数、土壤有效含水量等敏感性参数进行调试,采用2004—2005年数据验证模型适应性.结果表明:(1)年、月尺度径流模拟的相对误差(Re)在 ± 12% 以内,相关系数(R2)、效率系数(Ens)均大于0.80,AnnAGNPS 模型能够很好地模拟灞河流域产流规律;(2)研究区年径流深介于66.9~727.6 mm,其中乔木林的产流系数最小,耕地的产流系数是乔木林的1.5倍.不同土地利用类型的产流系数及其等级划分为后续非点源关键源区识别提供定量参考,对地方政府开展水质目标管理有一定借鉴作用.%Annualized agriculture non-point source pollution(AnnAGNPS)model was employed to simulate the runoff in the Bahe River Basin,Xi'an city.Based on the observation data of Maduwang provincial monitoring section, the sensitivity parameters such as CN value,channel Manning coefficient and saturated conductivity and field capacity were optimized.The model was calibrated and validated used 2002-2003 data and 2004-2005 data,respectively.Results showed that:(1)The relative error(Re)of annual and monthly runoff simulation was within ± 12%,correlation coefficient(R2)and efficient coefficient(Ens)were more than 0.80,indicating that the AnnAGNPS model could well simulate the runoff of Bahe River;(2)The annual runoff depth of the study area ranged from 66.9 to 727.6 mm, among which the runoff coefficient of the arbor forest was the smallest,and the runoff coefficient of cultivated land was 1.5 times that of the arbor.The land use of runoff coefficient and grade division of different land use types provide a quantitative reference for the follow-up non-point source key source area identification,which could be used for reference to the local government to carry out water quality management.