陕西省不同生态类型区河流水质与径流泥沙间的关系

Relationship Between River Water Quality and Runoff and Sediment in Different Ecological Type Areas of Shaanxi Province

为反映陕西省地表水水质状况与水土流失间的关系,选取不同生态类型区的3条主要河流(渭河、延河和汉江)为研究对象,依据河流27断面水质监测资料,对延河流域5个断面、渭河流域13个断面、汉江流域9个断面的水质进行了评价,并从水体污染的角度分析了3条典型河流的污染源及其与径流泥沙的关系。结果表明:不同生态类型区河流水体水质呈现明显的时空变化特征,3条典型河流2001—2010年水质改善明显,27个监测断面中满足Ⅰ—Ⅲ类水质水体功能的断面由11个增加到18个,达标断面率为66.7%,Ⅴ类水质断面9个,占33.0%;不同生态类型区河流水质污染呈现较大的南北空间差异,位于秦岭以北的渭河干流污染严重,属重度污染,延河属轻度污染,位于秦岭以南的汉江水质为优;渭河氨氮浓度与年径流量呈显著负相关,径流量越大,氨氮浓度越低;延河河流径流与溶解氧(DO)浓度呈显著正相关,径流量越大,DO浓度越高,水质越好;汉江年输沙量和高锰酸盐指数(CODMN)浓度呈显著正相关,输沙量量越大,COD_(MN)越高,水质污染越严重。

For a more comprehensive and true reflection of the relationship between surface water quality and soil and water loss in Shaanxi Province,three main rivers,Weihe River,Yanhe River and Hanjiang River,were selected as the research objects.According to the water quality monitoring data of 27 river sections,the water quality of 5 sections of the Yanhe River Basin,13 sections of the Weihe River Basin,9 sections of the Hanjiang River Basin was systematically evaluated.In the view of water pollution,we analyze the relationship between the pollution sources and the runoff,sediment of three typical rivers.The main conclusions are as follows.The water quality of the three typical river water bodies showed obvious temporal and spatial characteristics.From 2001 to 2010,the quality of the three typical rivers improved significantly.From 2001 to 2010,the cross-sections of the 27 monitoring sections inⅠ—Ⅲ water quality increased from 11 to 18,the increasing proportion was 66.7%.water qualityⅤwas found in 9 monitoring sections,accounting for 33.0%.At the spatial scale,the pollution of the three typical rivers showed the significant difference from north to south.The Weihe River in the north of the Qinling Mountains was seriously contaminated;the Yanhe River was slightly contaminated and the water quality in Hanjiang River in the south of the Qinling Mountains has be excellent for ten years.There was a negative correlation between NH3-N concentration and runoff volume in the Wei River,the greater the runoff,the lower the NH3-N concentration.In the Yanhe River Basin,the DO concentration was a positive correlation with the annual runoff volume,the greater the runoff,the higher DO concentration.There was a positive correlation between the annual sediment load and the concentration of COD（MN） in the Hanjiang River,the greater the amount of sediment transport,the higher the CODMN,the more serious water pollution.