Research On The Rational Exploitation Of Groundwater Resources In Liguanpu Water Source Area In Shenyang City

Built in 1958, Liguanpu water source, located on the north shore of Hun River floodplain in the southwest of Shenyang City, is one of the main water supply sources of Shenyang. With an area of 37.88km2, it is a typical water source near river, which design supply capability is 20×104m3/d. Before the year 2000, as the exploitation quantity was kept between 15.4m3/d and 22.2m3/d, 3 three local depression cone of groundwater formed. However, as the exploitation quantity decreased sharply to 6.79×104m3/d after 2000, groundwater picked up gradually. At present, due to the increasing of the industrial water requirement, the groundwater exploitation can be increased in the waterworks, the former 20×104m3/d can not represent its real exploitable ability, so it is necessary to reevaluate the waterworks which has run for 45 years. The paper takes the topic of"The research on the rational development and utilization of groundwater resources in the Li Guanbao waterworks in Shen Yang", it calculated the groundwater exploitable quantity by the numerical model on the base of the present groundwater development analysis, and also worked on the groundwater exploitation potential, finally came up with the scheme of the rational development and protection of groundwater resources. The research no only supplies the scientific reference to the city and life water demands and management, but is also important to the the field social and economic sustainable development.Quaternary groundwater that contain phreatic aquifers and confined aquifers in Liguanpu water source are the object of water resources assessment. Based on the datum including weather, hydrology, geology and hydrogeology, the thesis analyses the hydrogeologic structure features of aquifers and the recharge, runoff, discharge and dynamic characters of groundwater. According to 48 borehole data and geologic and hydrogeologic data in study area, the 3D visual model of hydrogeologic structure in Liguanpu water source is established by GMS software, and the distribution of aquifers in study area is displayed directly. The aquifers in study area are the sandy gravel alluvium and diluvium phreatic aquifers, Quanternary Holocene, the sandy gravel alluvium and diluvium weak confined pore aquifers, upper Pleistocene and the sandy gravel glaciofluvial deposited diluvium confined aquifers, lower Pleistocene. The total thickness of aquifers is about 80m, and the aquifer is homogeneous and gently.On the basis of completely understanding the geological and hydrogeological conditions, the hydrogeological model is established, and groundwater in study area is generalized as heterogeneous isotropic two-dimensional unsteady flow of phreatic water. The math equation is established, which is calculated by Visual MODFLOW software. In the following, the established model is identified and validated by the water level observation data and groundwater field from Feb 15, 2002 to Sep 15, 2003. The results indicate: the established model describes the groundwater system characters actually, and it meets precision requirement. Then the recharge and discharge rate are calculated. The total recharge amount of groundwater in study area is 5031.2×104m3/a, the river leakage amount and lateral groundwater recharge amount are 68.2 and 19 percent of the total groundwater recharge amount respectively. The total discharge amount is 4503.2×104m3/a, artificial yield of water is 91.2 percent. The budget is 528×104m3/a. For certificating the reliability of this model, budget analysis method is applied, the result indicate: budget result is the same as the numeric model result, and the model can be used to predict.To understand the operating state of water source in different conditions and make rational exploitation of groundwater resources, 4 different prediction programs is made, that are suspending the present distribution of groundwater and present exploitation quantity(6.79×104m3/d) , the model forecast 1 year by precipitation of different guarantee rate 20, 50, 75, 90 percent respectively. The precipitation amount after 2005 are forecasted by historical period method and frequency analysis method, the exploitation program are suspending the present distribution and present exploitation quantity(6.79×104m3/d), the model forecast 10 years; suspending the present distribution and changing the exploitation quantity, the model forecast 10 years; changing the distribution and exploitation quantity, the model forecast 10 years respectively. The forecasting indicates:①under the present exploitation(which is equal to 6.79×104m3/d), the groundwater is in the state of positive equilibrium in all years of different precipitation guarantee rates. Besides, with the time goes on, the groundwater level can recover gradually. When the groundwater exploitation is enlarged to 21.94×104m3/d, the groundwater level falls rapidly, and will lead to the combination of the two cones of depression in the first waterworks and the sanded factory, which exists in the whole zone, besides, another small cone of depression in the southeast by north, at this time, the groundwater exploitation exceeds the groundwater exploitable ability, the sustaining exploitation will cause the dewatering of the aquifers and other environmental geological problems. When the groundwater exploitation decrease to 10.03×104m3/d in 2009, the groundwater level restores, the cone of depression decreases, that is, this quantity is reasonable to the sustain the groundwater level, it's the reasonable exploitation.②the main factors effect the groundwater level changing are the groundwater exploitation and the seepage from the rivers, then is the precipitation seepage, the groundwater resources change little with the plentiful and scanty seasons.③after the exploitation layout is adjusted, the groundwater level restores, it is because that the groundwater captures more Hunhe and the lateral runoff in the east, so the forth exploitation layout scheme is suggested to the groundwater exploitation, the rational exploitation is 10.03×104m3/d.Finally, the rational utilization and protection of the groundwater resources is put forward by the technique, economy, and education propaganda with different view points.