沩水流域土地景观格局对河流水质的影响

以红壤丘陵区沩水流域为研究区域,运用GIS空间分析及统计分析的方法,探讨了流域土地景观格局对河流水质的影响。结果表明：① 林地面积百分比与电导率(COND)、综合污染指数(Pr)相关性指数分别达-1.000、-0.997,呈显著负相关;耕地面积百分比与COND、总磷(TP)及土地利用程度综合指数(La)与COND、Pr呈显著正相关。② 斑块数量(NP)、香农多样性指数(SHDI)与COND、Pr相关性指数均在0.997以上,呈显著正相关;平均斑块面积(AREA_MN)、蔓延度指数(CONTAG)与COND、Pr及最大斑块指数(LPI)与TP呈显著负相关。③ 从时间上看,所选用的大部分土地景观格局指标与pH值、溶解氧(DO)在丰水期与枯水期的相关性状态相反,且枯水期土地景观格局对河流水质的影响较丰水期更为显著。

The effects of land-use and landscape pattern on water quality in Weihe river watershed

This study, with the sampling case of Weihe river watershed in red soil hilly region of southern China, attempts to investigate the effects of land-use and landscape pattern on water quality respectively. The GIS spatial analysis and statistical analysis are employed based on the water quality monitoring data and TM data from January to December in 2010. There are two sub-sections in this study. One is the relationship analysis between land-use and water quality. The data analysis results indicate that the correlation coefficient of percentage of woodland area with conductivity (COND) reaches -1.000. Likewise, the correlation coefficient between percentage of woodland area and comprehensive pollution index (Pr) is -0.997. That is to say, percentage of woodland area has significant negative correlations with COND and comprehensive pollution index (Pr), respectively. In contrast, the percentage of farmland area is significantly positively-correlated with COND and total phosphorus (TP). Specific to the indicator of comprehensive index of land use degree, there is also a significant positive correlation with COND and Pr.The other one is the relationship analysis between landscape pattern and water quality. The indicators, which have significant positive correlations with COND and Pr respectively, are number of patch (NP) and Shannon diversity index (SHDI), because their correlation coefficients are all above 0.997. Furthermore, the indicators, having significant negative correlations with COND and Pr respectively, are average patch area (AREA_MN) and contagion (CONTAG). Also, there is a significant negative correlation between largest patch index (LPI) and TP. What is more, it is found that, in term of time scale, a majority of land-use and landscape pattern indicators present opposite correlation results with pH value and dissolved oxygen (DO) in dry season and wet season respectively. Moreover, the effects of land-use and landscape pattern on water quality in dry season are more significant than that in wet season. These research findings are meaningful for water quality improvement, which can help local governments in optimizing the land-use and landscape pattern in watershed areas, hence achieving the balance between exploitation and protection of water resources.