Evaluation On Groundwater Resource Of Changchun Emergency & Standby Water Source

With the increase of urban population, accelerated urbanization process, water security of urban water supply increasingly become an important issue to restrict the harmonious development of the urban socio-economy and ecological environment. Moreover, water shortage and water pollution has become a major problem of the urban water resource environment at domestic and abroad. The supply rate of urban water resources coping with drought and emergencies is critical point of urban water supply security. The emergency water supply capacity become the key link of urban water supply security when drought and emergencies happened.Changchun is a city suffering desperate shortage of water. Water shortage seriously threatens thedevelopment and construction of this city. Therefore, it becomes a new task for the urban water source construction that how to utilize the storage and regulation function of underground reservoirs, exploit the local groundwater potential and construct emergency and standby groundwater sources in order to alleviate contradiction between the shortage of resources and the economic development. Under such background, this paper researches the groundwater resource for the construction of Changchun emergency and standby water source.Shitoukoumen Reservoir is located in Jiutai, Changchun, Jilin Province. The reservoir dam is apart 500 m from Shitoukoumen in southwest, in Xiyingcheng town, Jiutai. Changchun emergency and standby water source is located at the north of the reservoir, Yinma Valley floodplain and the first and second terrace, rich in groundwater resources, mainly abundant in the Quaternary pore phreatic water and the Tertiary clastic rock pore confined water.The area of the water source is 159.66km~2, the total recharging amount of Quaternary phreatic water in pumpage condition is 224096.91m~3/d, the exploiting amount is 403748.19m~3/d, which is 179651.28 m~3/d more than the recharging amount. The imbalance exploit and recharge can only be adjusted by using deposited resource. The deposited gross in pumpage condition is 46445.42×10~4m~3, and the over-exploited volume in 90-day production period is 1616.86×10~4 m~3, which accounts for 3.48% of the deposited gross. The exploiting area of Tertiary confined aquifer is 76.37km~2, the groundwater exploiting volume in 90-day production period is 981×104m~3, and the flexible deposited volume of exploiting area is 2860.67×10~4m~3, the exploiting volume is account for 34.29% of the flexible deposited amount, which means it can guarantee the exploit. Quaternary phreatic groundwater in Yinma River area is good quality, but Shuangyang River valley groundwater is poor quality because of the higher content of iron and manganese ions and nitrate content exceeding the standard in some local area, which shoud be treated appropriately in order to meet the requirements of domestic water. Tertiary fractured pore confined aquifer with good-quality water is a good drinking water reserve.Changchun emergency and standby water source will be started using in the case of water stress in Changchun. It can satisfy the demands of water supply when meeting the unexpected event of drought or emergency, be in conformity with the principle of rational development and economical utilization of the water resources, and bound to make due contributions for harmonious and stable social and economic development of Changchun.