滇池流域土地利用变化对地下水水质的影响

土地利用变化影响着浅层地下水水质,以滇池流域为研究对象,综合运用遥感影像解译、马尔科夫转移矩阵和冗余分析,对近20年(2002～2020)滇池流域土地利用和浅层地下水质变化进行分析,揭示长时间尺度下土地利用变化对浅层地下水水质的影响.结果表明:2002和2020年滇池流域土地利用类型以草地、林地和耕地为主,分别占总面积20.91%和17.43%、43.21%和37.99%、22.11%和17.08%,2002～2020年间耕地向建筑用地和林地、林地向草地和耕地、草地向林地和建筑用地转移概率分别为22.59%和20.72%、13.16%和10.49%、26.30%和15.65%,耕地面积减少146km²,建筑用地面积增加279km².2002～2020年滇池流域浅层地下水化学类型由HCO₃^-·SO₄^2--Mg²⁺型转变为HCO₃^-·SO₄^2--Ca<...

Effects of land use change on groundwater quality in the Dianchi Lake Basin

Land use change impacts on shallow groundwater quality. The changes of land use and shallow groundwater quality in the Dianchi Lake Basin in recent 20years (2002~2020) were analyze by comprehensive use of remote sensing image interpretation, Markov transition matrix and redundancy analysis, and the impact of land use change on shallow groundwater quality in a long time scale was revealed. The results showed that the land use types in 2002 and 2020 in the Dianchi Lake Basin were mainly grassland, forest land and cultivated land, accounting for 20.91% and 17.43%, 43.21% and 37.99%, 22.11% and 17.08% of the total area, respectively. The transfer probabilities of cultivated land to construction land and forest land, forest land to grassland and cultivated land, and grassland to forest land and construction land were 22.59% and 20.72%, 13.16% and 10.49%, 26.30% and 15.65% from 2002 to 2020, respectively. The area of cultivated land decreased by 146km², and the area of construction land increased by 279km². From 2002 to 2020, the chemical type of shallow groundwater in the Dianchi Lake Basin changed from HCO₃^-·SO₄^2--Mg²⁺to HCO₃^-·SO₄^2--Ca²⁺. The quality of shallow groundwater decreased from Class I and II to Class IV and V, and the overall water quality has deteriorated. Grassland and forest land were negatively correlated with TN and NO₃^--N, showing a “sink” effect, while construction land was positively correlated with TN and NO₃^--N (P < 0.05), showing a “source” effect. Our results revealed that changes in the spatial pattern of land use in the Dianchi Lake Basin significantly affected the quality of shallow groundwater. Construction land and cultivated land were the main drivers that led to the deterioration of shallow groundwater quality in the Dianchi Lake Basin. Reasonable planning and utilization of land resources are crucial to improve groundwater quality in the Dianchi Lake Basin.