Contrast Study On Dynamic Changes Of Water Chemistry And Aqueous Medium Anisotropy

Karst water is an important water source of humans, a quarter of the world’s population are relying on karst water as the main source of drinking water. The carbonatite’s distribution area is about3.44million square kilometres in china, including Guizhou,Guangxi,Yunnan, Chongqing, Sichuan Hu’nan,Guangdong and other provinces, it’s about one third of our national territorial area; and the karst groundwater resources are203.967billion steres annually, it’s about a quarter of our country’s groundwater resources. Chongqing’s karst groundwater resources are11.835billion steres annually, it’s about73.65%of groundwater resources; and in this area the underground water resources are4.777billion steres annually, they mainly distribute on the southeast and northeast area of Chongqing. Currently, the karst water system is seriously polluted by unreasonable development and utilization in this area, meanwhile the karst eco-environment’s degradation weakened the self-storage capacity and the purification ability, which aggravate the inhomogeneity of space-time distribution of groundwater resource, total water resources decrease and water quality deteriorate. The globle climate change and rapid development of social economy seriously increased the pressure on resources and environment, it appears more urgent to ensure the the safety of the people’s production and living water in the changing environment.This paper started from the protection of karst groundwater and environment, select the Nanshan Laolongdong and Qinguguan subterranean river basin as the study areas; collected the hydrology geology and geomorphology data, vegetational cover and land utilization data. Guided by the earth system science to clear up the natural environment climate and hydrology conditions, to observe and prospect the influence factors of aquifer’s development (such as weather, climate, geology, geomorphology, soil, hydrology and land-use conditions); use the methods as tracer experiment, hydrological response event, hydrochemistry dynamic monitoring and contrastive analysis and so on, to study the karst groundwater flow dynamic characteristics and the anisotropy of aquiferous medium of Nanshan Laolongdong and Qinguguan subterranean river basin.According to the hydrology data in2012of NanshanLaolongdong and Qinguguan subterranean river basin to anslysis. According to the hydrological data of Nanshan Longdong and Qingmuguan subterranean river, these two rivers are multi-segment karst groundwater, the Qinguguan subterranean river’s decay curve consists of three segments, and the Nanshan Laolongdong subterranean river’s decay curve consists of four segments. It shows that the aquifer in this area is a multi-level structure with different leveled water space, from the top down is big passageway, karst cave, crack and fissure; and the main structure is crack-hole space. The regression analysis shows that flow and rainfall of Nanshan Laolongdong subterranean river are well-correlated. But the correlationship between the flow and rainfall of Qinguguan subterranean river is not as well, the reason is that a reservoir was built at Ganjiacao depression on the upstream to solve the water problem, hold back the upstream’s rainfall, the Yankou ponor had no afflux, the quarry and small coal mine on the middle and lower stream use a lot of water, all these factors made the shortage of subterranean river flow.According to the wild automatic monitoring and lab test technology, record these two rivers’ hydrogeochemistry dynamic change process in long and short time-scales, and statistically analysised the correlationship between those indexes. Ca2+, Mg2+and HCO3-are the main products of carbonate’s solution, their value can reflect the strength of water-rock interaction. The flow quantity and rate of Nanshan Laolongdong subterranean river are more than the Qingmuguan subterranean river, and so does the strength of carbonate dissolution caused by karstification. The K+, Na+, NO3-, SO42-, Cl-mainly come from agricultural fertilizer and household garbage, and they can reflect the pollution degree of groundwater. In the Nanshan Laolongdong subterranean river basin, with urban expansion the city’s construction land and emissions of municipal sewage increased rapidly, a large number of municipal sewage was discharged into the subterranean river, led to the content of K+and Na+rise up. But the Qingmuguan subterranean river basin is almost farming activities, residents are center on the basin, upper and middle basin has only a little population, the K+and Na+mainly come from rainfall, agricultural fertilizer and human excrement, and only in the farming period or short-term rainfall cases showed higher levels.By the changes of flow and hydrogeochemistry to analysis Nanshan Laolongdong and Qingmuguan subterranean river systems, and combined with predecessors’ research results found that Nanshan Laolongdong subterranean river has U-shaped bifurcation and down developed siphon type pipe, except the main passageways it also has pool or lake on it. But the section of Qingmuguan subterranean river system from Yankou ponor to Jiangjiaquan groundwater runoff is a typical turbulence flow regime, no crossroads, extremely uneven aquiferous medium, and it is mainly sole karst pipe network.