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

Abstract

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 p H 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.