基于遥感和GIS的赤水河水质对流域土地利用的响应研究

利用2009年TM影像和11个断面的水质监测数据，同时在缓冲区和子流域尺度上，分析了赤水河流域内土地利用方式与水质指标（溶解氧、高锰酸盐指数、氨氮）之间的相关关系，并建立水质对土地利用结构的空间响应模型。由相关性分析得：从缓冲区尺度到子流域尺度，建设用地与氨氮的相关性由显著正相关变为高度正相关，相关系数达到0836；与高锰酸盐指数的相关性则由普通正相关变为显著正相关，相关系数为0776。耕地与高锰酸盐指数的相关性由显著正相关增加为高度正相关，相关系数达到0913；与氨氮的相关系数也增加到0782；而耕地与溶解氧则由缓冲区尺度的一般负相关变为子流域尺度的显著负相关，相关系数达0609。在缓冲区尺度上，林地与氨氮、高锰酸盐指数呈负相关，相关程度总体上随着缓冲半径的增大而增大；而当研究尺度为依自然属性划分的子流域时，林地与氨氮呈现出显著负相关，相关系数达到0673；与高锰酸盐指数呈现出高度负相关，相关系数达到0822；且在子流域尺度上林地对溶解氧的“汇”的作用才充分表现出来，相关系数达0718。研究结果表明：赤水河流域土地利用方式对水质有重要影响。赤水河流域内的城镇建设用地和耕地对流域水质有着严重的负面影响，承载在其上的城市生活、工业污水和农业面源污染(种养殖)是河流水质污染的重要污染源。林地对流域的水质污染有重要的缓解作用。总体上，各水质参数与土地利用类型间的相关性在子流域和缓冲区两种尺度下表现出一致的规律，但这种相关性在子流域尺度下表现的更为显著。研究成果可为赤水河流域的水污染防治、土地利用方式优化提供科学依据,并为同类研究提供借鉴

RESPONSE RELATIONSHIP BETWEEN LAND USE AND WATER QUALITY IN CHISHUI RIVER BASIN BASED ON RS AND GIS

The relationship between land use/land cover(LULC) and water quality is one of the important components of land use environmental effects research. The type, size and distance of different land use types to water bodies are usually studied in a manner relating them to water quality. With Landsat Thematic Mapper(TM) images and the water qualities in 11 monitoring sections, this paper analyzed the relationship between land use and water quality parameters(DO, CODMn, NH3 N) in Chishui River basin on the buffers and sub watershed scale，and made multiple regression model of water quality parameters. Based on Geographic Information System (GIS) spatial analysis, round types of contributing zones were developed around these monitoring sections. And based on GIS hydrology analysis, the sub watersheds were segmented. Then, six types of land use types were extracted from TM images in 2009. On the basis of water quality parameters, the correlation relationship between water quality and land use pattern over different contributing zones was examined. Correlation analysis showed that, from round types of buffers to sub watersheds scale, the correlation of construction land and NH3 N increased form significant positive correlation to high positive correlation, and the correlation coefficient reached 0.836. The correlation of construction land and CODMn increased form positive correlation to significant positive correlation, and the correlation coefficient reached 0776. The correlation of cultivated land and CODMn increased form significant positive correlation to high positive correlation, the correlation coefficient reached 0913.The correlation coefficient of cultivated land and NH3 N increased to 0782. The correlation of cultivated land and DO increased form negative correlation to significant negative correlation, and the correlation coefficient was 0.609. On the buffer scale, the forestland exhibited negatively correlated with CODMn and NH3 N，and the degree of correlation increased with the increase of buffer radius. While on the sub watersheds scale, the forestland exhibited significant negative correlation with NH3 N and highly negative correlation with CODMn, the correlation coefficient reached 0.673 and 0.822, respectively. All of these showed that the land use patterns in Chishui River basin had great impacts on surface water quality, and construction land and cultivated land gravely influenced the water quality in Chishui River basin. City domestic sewage, industrial sewage and agricultural non point source pollution hosted on these land use types are the important sources of water pollution. Nevertheless, the shrub grass and forestland showed positive effects to some extent. Generally, the correlativity between land use and water quality parameters was consistently on both buffers and sub watershed scale in Chishui River basin, while it was exhibited more significant on sub watershed scale .On buffers scale, we cloud analyze the effect of the distance between land use types and the river on water quality. However, the natural attributions of sub watershed cloud be taken into account on sub watershed scale. The research could provide both critical information in sustainable land use practice for water resource conservation for Chishui River basin, and a methodological reference for analogous study