| The trial construction of two-oriented society for Changsha-Zhuzhou-Xiangtan urban agglomeration is not only an important growth pole of Hunan province, but also the significant part of the strategy for our national central rise. And its essence is to construct a resource-saving and environment-friendly society. There have done a lot of comprehensive systematic work in the past, however far behind the time, the presicion of the work is low and the cover range is not consistent with the "two-oriented society" testing area completely.Therefore, the evaluation on the potential of groundwater resource for the test area of the city group of "two-oriented society", the investigation of the groundwater resource development and utilization status, the analysis on the potential of groundwater exploitation,the proposed countermeasures of the sustainable development and utilization of the groundwater and the protection measures of groundwater in this region are urgently needed.On basis of a comprehensive analysis for the previous geological and hydrogeological achievements of the studying area, a conceptual model initially is setting up in this paper. The hydrogeological groundwater in this region mainly contained four types:pore water in unconsolidated rocks, pore fissure cave water in clastic rocks, fissure cave water in carbonate rocks and bedrock fissure water. In which the pore water in unconsolidated rocks,covering only small area, accounts for77.78%of the total amount of groundwater resources.According to the distribution characteristics of the different types of groundwater in the study area, the hydrogeological zoning has been finished.Then taking the suitable evaluation method for the potential of resources,I calculate the amount of groundwater resources. Frequency analysis methods are used for precipitation data in order to ensure that the rate of P=75%in rain season,flat season and dry season in a flat rainfall year, and guarantee the rate of P=95%in abundance, flat and dry season rainfall in a dry year and calculated separately the pavement meteoric recharge as the amount of natural recharge resources. The average year precipitation recharge is1640921m3/d, dry year precipitation recharge is1339125m3/d. The volume of the calculated groundwater storage resources in the study area is259959×104m3. Using the analytical method, the average cloth wells method and spring domain method,the available exploitation groundwater resources are calculated,which come to the amout of649323m3/d in the study area.In this paper by using the mining potential index method, I processed the evaluation on the mining potential of groundwater resources in the study area. The mining potential areas include Changsha, Changsha County, Wangcheng, Zhuzhou, Xiangtan County. And the mining potential indexes (P) are from1.49to5.12. The groundwater resources in Zhuzhou County are balanced between recharge and mining and the potential index (P) is1.07.The mining potential indexe (P) in Xiangtan City is0.70, which is overexploited.By using the comprehensive evaluation score method, I evaluated the quality of groundwater in the study area. At the same time the evaluation on the physical and chemical characteristics of the groundwater and the evaluation on domestic water and irrigation water have also been finished. Hydrogeological environmental problems of the study area were discussed and analyzed. Area groundwater is mainly affected by the contamination of non-metallic contaminants. The ammonia nitrogen and nitrite nitrogen pollutions are also serious. The metal pollutants are mainly of iron, manganese, which are only distributed in the local small area. Lead, zinc, arsenic and mercury pollutions, yet mild, are distributed mostly punctuately.According to the geohydrological conditions and water supply characteristics of the study area, I took20rich-supply water areas for the proposed source water areas. The emergency groundwater-supply areas should be considered on the following indicators:recoverable resources, recoverable modulus, water depth, aquifer depth, single well inflow and regional transportation advantages, during which seven areas are chosen as the favorable comprehensive emergency water source in the study area. |
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