滇池流域土地利用对入湖河流水质的影响

摘要

Based on data of interpreting TM orthophoto images and water quality monitoring in July 2008, the correlativity of landuse, which was categorized to urban,agriculture, forest and grassland by National Standard for Landuse Category in China, and water quality was analyzed in terms of the whole watershed and sub-watersheds. In whole watershed of Dianchi lake, the urban landuse proportion illustrated positive relations with the water pollution stand(indicating with concentration of CODMn, TP, TN and NH3-N in water), while the other three types of landuse, agriculture, forest and grass, showed negative relations. The urban landuse was the major contributor to pollutants in the watershed, which submerged the contribution of cultivated land. Furthermore, classified 21 sub-watersheds to be 3 types, urban, agriculture and forest -watershed according to different proportions of landuse in the each sub-watershed. There were constant positive relationships between the urban-watersheds and water pollution,while negative relationships were observed for the forest-watershed. Also, the impact of landscape spatial pattern on water quality was discussed. The proportion and pattern of landuse both exerted great effects on the water quality at the scales of the whole watershed and the sub-watershed.%利用滇池流域2008年TM影像数据和入湖河流67个监测点的水质数据,以子流域为基本研究单元,从子流域综合分析和子流域分类分析两个角度,研究土地利用类型(国家分类标准)对入湖河流水质的影响.结果表明,21个子流域单元的水质污染指标(CODMn、TP、TN、NH3-N)与居民点及工矿用地呈显著正相关,与耕地、林地、草地呈负相关.对整个流域而言,城镇及工矿用地是入湖河流水质污染的主要来源,其污染贡献掩盖了耕地的贡献；根据土地利用结构和空间分布格局的差异,将滇池流域的21个子流域分为3类(城镇及工矿用地为主、耕地为主、林地为主).分类分析表明,水质污染指标与居民点及工矿用地始终呈现正相关,与林地始终呈现负相关.同时,讨论了土地利用空间格局差异对水质的影响,说明土地利用比例结构和分布格局对水质办具有重要影响.