The Groundwater Numeric Simulation Based On Web-Database Technology In ChangZhou Area

Changzhou area is located in the Yangtze River Delta hinterland. With the expanding of cities'scales and the economic rapid development, the water consumptions of industry, agriculture and domestic are increasing constantly, and groundwater has been in a state of continuous excessive extraction which constrains the economic sustainable development seriously in Changzhou area. Changzhou government has adopted a series of plans including compressing pumping and prohibiting pumping to solve this problem since 2000 year. In 2005, the government prohibited pumping groundwater in Changzhou entire area. In order to forecast the dynamic changing trends of groundwater level and quantitatively predict the recovery of groundwater level in the near future, as well as provide a scientific basis for rational pumping and utilizing groundwater resources, it is very significant to adopt numerical simulation of groundwater flow in Changzhou area.With the continuous improvements of research methods and the continuous progress of the investigation, the data which were needed in numeric simulation or can be got by investigation increase geometricly. So the database technology was adopt to manger the hydrogeological data in study area and assist the numeric simulation.The compressing pumping plan and prohibiting pumping plan is not only decided by government but also focused by the public. So the Web-Database technology and the WebGIS technology which are developing quickly in recent years , were used in this dissertation to release the hydrogeological data and the forecasted results of groundwater simulation. It can not only provide intuitively the dynamic changing trend of groundwater for society public in time, but also supply certain shareable data and fruit used for reference for future continuous study in Changzhou area.Changzhou area is selected as study area, and in order to make the groundwater system relatively independent, some areas along the Yangtze River in Jangyin were included in the study area. Because the first confined aquifer sporadic distributes along the Yangtze River, only the second and the third confined aquifer were simulated. Groundwater was pumped mainly from the second aquifer, so the second confined aquifer was focused on in the process of simulation.The main results of this thesis are as follows:1,A hydrogeological database was established by using Visual Basic programming language and SQL Server2000 database management system. Its main functions include:①Providing an effective means for storing and updating the hydrogeological data in the study area;②Searching the data quickly, which is needed by numeric model.2,A numeric model of groundwater flow was established. The identifying time of the model is from 1 July to 1 August in 1995. After identifying and verifying the model, the numerical model can reflect the actual hydrogeological conditions; the model can be used to forecast the groundwater level in future.3,The groundwater level in the administrative boundary between Changzhou and Wuxi was forecasted. This boundary is the first type of boundary. In order to forecast the changing trend of groundwater level in the future, forecasting the water level in this boundary was needed firstly. By analyzing the hydrogeological conditions, groundwater yield has dominant influence on water level at the boundary. So the water level in this boundary in the future can be forecasted by building a stochastic model using the mining amount of groundwater , the history water level in last year and the water level in current year. The water level in 2007 to 2010 was predicted by using regression analysis method and building regression equations.4,The groundwater level was predicted by numeric model of groundwater flow which began from 1 July in 2005 to 2010, based on the simulated water level in the first type of boundary forecasted. The results of the model show that the groundwater of the second aquifer recovers full-scale in the study area after carrying out the plan of prohibiting mining from 2005 year to 2010 year and the water level ascend about 2.5 meters in the second aquifer except the areas along the Yangtze River, where the water level is high. The water level in depression cone ascends from -77 meters to -72 meters.5,A release system on the internet was established by using Web—Database technology and the WebGIS technology. It helps to release the hydrogeological data and the groundwater fields simulated by the numeric model. The public can search the changing trend of groundwater level clearly in time form the release system; the other hydrogeological researchers also can get the hydrogeological data and reference from the release system.6,The groundwater fields which was exported by GMS were changed into the shapefiles format. The data of groundwater fields was re-organized by using Visual C++ programming language and the isoline of groundwater flow was generated by using this algorithm of generating the isoline based on grid. At last, changing the isoline into shapefiles format by using MapObjects.