| The groundwater is an important component of the water resources, and it is uniform and steady on space and time distribution, and it is uneasy to evaporate and pollute because of the protection of the first overburden. The loss of the groundwater is littler than that of the surface water and the groundwater has the better water quality, so it is the main headwaters of cities and towns and industrial and mining enterprises in the semi-dry and dry area. The project of 10 thousand tons per year of the polyvinyl chloride will be constructed. This research mainly meets to the demand of water use of 1.8-2.0 104 m3/d in the project in the near future. The water source land of Jijiamao in Mizhi County will be built. The paper points to the building water source area, considering whether there is water content in abundance and water quality, whether there are some effects on the groundwater level near it and the main water environmental problems caused by the run of the water source area. The writer evaluates the amount of the permitting exploitation and predicts the water level, then put the better pumping scheme and protecting measure.In the paper, beginning with geological and hydrogeological condition of water source of Jijiamao, the writer looks into the forming of groundwater, law of distribution, runoff and discharge, dynamic datum and evaluates the water quality of the groundwater. Then, basing on the practical problems of the studying area-the thickness of aquifer is little, the capability of depositing water is finite, the Quaternary loose stratum directly superimposes the bedrock strong breeze girdle, the writer thinks it is difficult to answer for the water use of the polyvinyl chloride project by the centralized tube well pumping. The writer presents that the catchments corridor should be used to excite the supply of the groundwater to the maximum extent and it is an effective way of getting the relatively large exploiting amount in this area. On the basis of the datum of a lot of pumping experiment, infiltrating water experiment, Analysis Method and Numerical Method are adopted for the hydrogeological parameters of aquifer. It shows the capability of the horizontal infiltration is obviously larger than that of the river vertical infiltration in the Quaternary aquifer of Wuding River bed and flood land, and the aquifer is anisotropic. The writer conceptualizes the hydrogeol ogical model, and the corresponding three dimension mathematical model has been built,the Finite Difference Method is used to solve the mathematical model. After calibration and verification of the model, the adopted geology parameters basically accord with the concrete hydrology geology condition. It is thought that the model is correct and reliable to use for the groundwater flow of the study area. The paper presents three plans of groundwater pumping. They are: the corridor is under riverbed, the corridor is 10 m from the west, and the corridor is 20 m from the west of river. According to the built mathematical model, the writer simulates and calculates the groundwater flow and the pumping. From the calculation result, the pumping in the 1st plan is 20968.42 m3/d with 3 Km' corridor. This meets to the demand of the water use of the project and has a little effect on the groundwater level on both sides of the river. The pumping in the 2nd plan is 9029.5 m3/d with 3 Km' corridor and the groundwater level steadily drops and the range of drop averagely is about 0.5m in the west of the river. The pumping in the 3rd plan is 5820.4 m3/d with 3 Km' corridor and the pumping is not enough for the demand of the project, this has great effect on the groundwater level of the west and the range of drop averagely is about 0.65m. Comparing these plans, the writer puts the best is the 1st plan and expounds the water environmental issues after exploiting and protective measure of water resource at last. |
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