The Simulation Of Hydrological Process In Qingmuguan Karst Underground River, Chongqing, China

The karst water is the important domestic and production water resource and it plays an important supporting role to social economic development in karst region. In Southwest karst areas of China, the reserves of karst groundwater resources are huge. But the karst surface water and groundwater exchange rapidly, the temporal and spatial distribution of karst water is uneven and karst groundwater pollution is aggravating. All of those caused the dwindling of karst groundwater resources that we can use. In recent years, the extreme weather is occurred frequently in China, especially in Southwest karst areas. In some regions, it comes to be a problem in domestic and production water because of successive drought. And it is one of the reasons for the difficulties of economic development in some karst regions. It is essential for utilizing water resources and responding extreme weather and hydrological events reasonably to study the process of runoff yield and concentration.The morphological characteristic of karst underground river was researched and hydrog-eological parameters were estimated by tracer test in Qingmuguan karst underground river system. A3D hydrogeological model was built based on basic geological data, hydrological data, field investigation, the basin boundary that determined by trace test and the series water level of Jiangjia spring. It was used to simulate the flux of underground river. The result shows that:(1) The break-through curve of the tracer has only one peak, it shows that the aquifer is developed with one conduit with a mean diameter of2.57m. And the friction factor, Reynolds number, Sherwood number were estimated by the test.(2) The break-through curve of the tracer of infiltration test has only one peak also. According to test data and the geography space information of underground rive, the average infiltration rate of the aquifer that from the test site to the conduit is estimated, and the result is49m/d. This value indicates that the information rate in this region is fast.(3) The discharge of Jiangjia spring was simulated by3D hydrogeological model with well result. The average absolute error of the simulated result is0.0458, and the root mean square error is0.0807. The simulated values were fitted with the observed values, the result shows that the simul- ation accuracy is more than95%. It can be indicated that the simulation results in rainy season is more accurate than that in dry season.