Research On Groundwater System And Delineation Of Groundwater Protection Areas In Sanji Horst

Taiyuan where groundwater is the main water-supply source over the years is the capital city of Shanxi Province. Groundwater in Lancun spring area is one of the main water supply sources in Taiyuan city. Sanji Horst is located in the southern boundary of Lancun spring area and the main linking channel between Dongshan and Xishan karst water systems. It has rich karstic groundwater with high-quality. Sanji Horst water source is a part of the Lancun spring area, but also a relative independent hydrogeological storage unit. With the quick development of society and economy in Taiyuan, water consumption is increasing year by year. Over-exploitation and indirect pollution of groundwater have resulted in the fundamental changes of recharge, runoff and discharge conditions of karstic groundwater system in Lancun spring area. In order to protect the groundwater in water source from pollution and attain the sustainable use of groundwater resources, it is necessary to analyze the karst groundwater system characteristics of Sanji Horst, designate groundwater protection areas and strengthen the management of water resources.On the basis of assembling and analyzing the research results on groundwater exploitation, monitor and test in Lancun spring area, the paper investigated and analyzed its natural geography, regional geology, hydrogeological condition and water resources exploitation situation. Based on the geological exploration as well as the borehole dates in and around the horst zone, the boundary location and properties of the Sanji Horst storage unit are determined. Besides, the paper also analyzed the stratigraphic layers and geological structure in horst zone where the karst groundwater stored, discussed the space structure, water circulation system, water chemical system and water dynamic characteristics of Sanji Horst karst groundwater system, and evaluated the quality of the karst groundwater. According to the relationships between the karst groundwater system and the water sources in Lancun spring area, combined with the regional hydrogeological conditions, the paper analyzed the influence of the atmosphere rainfall, the leakage of Fenhe river and the Second Fenhe reservoir and the exploration of other water sources on the groundwater level in Sanji Horst water source. Taking Lancun springs as the control system, a multivariate statistical numerical simulation model between the above mentioned factors and the groundwater level at Sanji Horst is established to predict the level dynamically. The paper forecasted the underground water level under different schemes by using the model and then calculated the corresponding hydraulic gradient value; according to the Technical Standards for Delineating Water Source Protection Areas, the paper calculated the Protected areas range of the Sanji Horst water sources (including the fifth waterworks and tenth waterworks in Taiyuan city) under different level years and different water supply schemes, designated water resources protection areas according to the hydrogeological conditions and ground building distribution in studied area and raised the measures to protect and manage the karst groundwater. The study result can provide certain theoretical basis and technical support to prevent water pollution in a planned manner, guarantee the water safety of urban residents and achieve the sustainable use of groundwater resources...