丹江口库区土地利用格局与水质响应关系

Response Relationship Research between Land Use Patterns and Water Quality in Danjiangkou Reservoir

为探究山地丘陵地区不同土地利用类型对流域水质的影响,利用2014年丹江口库区流域Landsat 8遥感影像数据(分辨率为30 m)和14条入库河流的水质数据,以库区14个小流域为基本研究单元,采用流域分割和多元统计分析相结合的方法研究土地利用类型对入湖河流水质的影响.结果表明:丹江口库区14条直接入库河流ρ(COD_(Cr))、ρ(TN)、ρ(NH_4^+-N)和ρ(TP)年均值分别为14.98、4.06、1.32和0.17 mg/L,可将其划分为3组,即清水保育型、轻污染防控型和重污染治理型,各组之间的显著性差异指标为ρ(COD_(Cr))、ρ(NH_4^+-N)、ρ(TN)和ρ(TP).冗余分析显示,建设用地对14条主要入库河流水质指标的影响最大,尤其是对重污染河流ρ(TN)、ρ(COD_(Cr))和ρ(CODMn)的影响较大,应划为蓝线优化开发区;耕地对清水保育型和轻污染防控型河流ρ(TN)和ρ(TP)的影响较大,并且对ρ(TN)的影响大于ρ(TP),划为黄线控制区;林地有助于削减水体污染物,是流域主要清水产流区,划为红线保护区.

The present study researched the influence of different land-use types in hilly areas on water quality indicators of reservoirs, taking Danjiangkou Reservoir as an example and using data of interpreting TM orthophoto images （resolution 30 m） and water quality monitoring of 14 branch-rivers with 14 watersheds as elementary units. The effects of land-use types on water quality of branch-rivers were analyzed by National Standard for Land Use Category in China using the method of reservoir segmentation and multivariate statistical analysis. The results indicated that the mean values of p （ CODCr ）, P （ NH4^＋ -N）, p （TN） and p （TP） in fourteen rivers into Danjiangkou Reservoir were 14. 98, 4. 06, 1.32 and 0. 17 mg/L, respectively. The rivers could be divided into three groups, group A （clean-water protection type） , group B （mild-pollution prevention type） , and group C （heavy-pollution governance type）. The index of significant differences between the groups were ρ（ CODCr）, ρ（ NH4^＋ -N） , ρ（TN） and ρ（TP）. Redundancy analysis showed that construction land had the most significant impact on the water quality in the fourteen rivers. In particular, the construction land had more influence on ρ（TN）, ρ（CODCr） and ρ（CODMn） in heavy-pollution governance type. Therefore, the construction land should be designated as the Blue Line Optimization District. Farmland had more influence on clean water conservation type and miLd-pollution prevention type, and the total nitrogen was affected more seriously than the total phosphorus. Thus, farmland should be designated as the Yellow Line Control District. Woodland was useful for reducing water pollution, and it was the main district of clean water production. It should bedesignated as the Red Line Protection District.