The Effects Of Land Use On Karst Water Quality In Karst Regions

Although only 15% of the Earth's surface is unaderlain by karstic rocks,more than 1 billion people living here,and have richness resources.But karst region is characterized by both surface and subsurface feature,karst groundwater have osculatoy relation,karst hydrogeology and ecosystem is very fraily,ease to be deteri- orated by human activeties. Water is a very important resorce to human's life.Because of "double-layer strucure"in karst region,the karst groundwater quality is very sensitive to land use change.We picked up a typical karst region of southwest China, Jinfo Mt. nature reserve in Chongqing,for surveys,field investigations,surveys and collecting previous data and new samples for experimental analysis in the laboratory.On the basis of previous research results and by means of the systematic analysis,contrast karst water quality in nature reserve and non-nature reserve,the effctes of land use on karst water quality are approached.Because karst region is characterized by both surface and subsurface,karst groundwater quality is very sensitive to unwise land useThrough contrast karst water quality in nature reserve and non-nature reserve,we find the content of Ca²⁺, HCO₃^-, SO₄^2-, NO₃^- and Cl^- have rised,total alkalinity have descended, living sewage and chemical fertilizer give rise to nitrate content in karst goundwater.Based on the factual date of groundwater chemistry in 1977 and 2004,we find not only kast groundwater quality in non-nature reserve is more worse than before ,karst groundwater quality in nature reserve is also changed.We contrast karst water quality in nature reserve and non-nature reserve,find karst groundwater quality is affacted by land use ,geology background and precipitation period change.In these three factors,land use change is the most important factor to karst...