采用GIS空间分析技术,对坪山河流域1990和2000年的土地利用结构变化进行分析,并结合土壤普查资料和降雨数据,利用长周期水文影响评价模型(L-THIA),以TP、TN为评价指标,对非点源污染负荷进行分析.结果表明:由1990年到2000年,耕地、园地有向建设用地转化的趋势,其中耕地和园地所占比例分别由原来的7.8％和12.4％减少到3.2％和8.7％,建设用地和水域所占比例分别由原来的1.8％和1.9％增加到7.5％和2.4％.同时,非点源污染敏感区不断扩大,平均径流量增加了9.6％；TN污染负荷由1990年的483.2t增加到2000年的498.4t,TP污染负荷从29.2t增加到36.3t.%The structural changes of land use in the Pingshan River Watershed in Shenzhen City in 1990 and 2000 were analyzed using GIS spatial analysis technology. Based on the soil survey map and precipitation data, the L-THIA model was used to estimate the non-point source pollution load with TN and TP being the estimation indices. The results show that, from 1990 to 2000, the area of farmland and garden plots decreased from 7.8% and 12.4% to 3.2% and 8.7% , respectively, and the construction area and water area increased from 1.8% and 1.9% to 7.5% and 2.4%, respectively, indicating a trend of transformation from farmland and garden plots into construction land. In addition, the areas sensitive to non-point source pollution were expanding. The average runoff volume increased by 9.6%, and the loads of TN and TP increased from 483.2 t and 29.2 t in 1990 to 498.4 t and 36.3 t in 2000, respectively.
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