Feasibility Research And Development Of Groundwater Reservoir In Tao-er River Fan Of JiLin Province

The area of Tao-er river is the biogeocenose transition from subhumid forest grassland to semiarid and desert zone. These problems such as drought, flood, alkalinization, sand blown by wind, grassland degradation, water and environment exacerbation become a system problem in this area, among which drought is the most serious. The rainfall has reduced a great deal and Tao-er river has been in water interception state in the area since the deluge of 1998. The amount of actual water supply of Taobei area was 415.1233 million m3 in 2003 year, but the amount of practical water use reached 271.14806 million m3. The main method to obtain the amount of lacking water is by exceeding exploitation of groundwater. With practical investigation the water resource actuality of research area are as follows: the groundwater table has been declining. The civil wells in the advancing edge and both alares parts of Tao-er river fan are discarded as useless. The inhabitants have to deepen the wells or use money to redrill wells. Farmers'burden aggravated and the agriculture's capability of resisting disaster reduced because of the energy loss and the cost of irrigation increasing. But the problem can't be settled even well are deepened in some areas. The inhabitants have to emigrate. The water resource problem has already endangered people's daily life. A mass of bore data have been collected in this research area and field investigations have been carried out to make-up and correct the data obtained. By Boreholes and Solids module of GMS(Groundwater Modeling System) software, geological condition has been visual , which affords powerful evidences for demonstrating the feasibility to build groundwater reservoir. By analyzing a lot of geological ,hydrological etc data, the methods to determine the hydrological parameters have been collected and calculated respectively. The data of groundwater table from 1995 to 2001 has been collected, and contour of groundwater has been worked out from the intuition to comprehend the instance of groundwater flow field. Furthermore, according to the existing state at home and abroad, together with the geological and hydrogeological conditions in the area to build groundwater reservoir, the characteristic parameters are determined. Besides these, all the recharge sources and discharge approaches are analyzed and the amount of recharge and discharge of the groundwater reservoir are worked out. Using the method of water amount bugeyt, the calculation errors are analyzed to satisfy the accuracy, and to check the given parameters again. This paper focuses on building mathematical model of groundwater reservoir, modeling the groundwater flow by Modflow of GMS. The discriminating period of the model is in 1997, when the errors of water quantity equilibrium is the smallest. The efficiency of model is preferable because the formers have done a great deal of researches about the area and all data are accurate. So it needn't to adjust the parameters greatly. The years from 2000~2001 is made as the model checking-out time, because Tao-er river has been water interception since 1998 and the river is also water interception in the modeling phase. So the period which is similar to the modeling conditions is chosen as calibration period, and the result of calibration satisfy the accuracy. This paper has researched the treatment of water interception of Tao-er river and designed three schemes. The first one is simulating different conditions inclusive interception and non-interception phase respectively; the second one is transforming the form of river to wells and calculating the amount of recharge that the river gives to the groundwater. Then this part of water is injected to groundwater aquifer with a series of injecting wells; the third one is simulating by subsections, which is to determine the probable location of the water interception according to the observed data and field investigation. Part of the rivers which have practical value are chosen as river conditions, while the others as no river conditions. Comparing the strongpoints and shortcomings of the three schemes, the optimal one is selected as the subsequent simulating project. And it is used to predict the groundwater table of studying area from 2001 to 2020. Using the method of Time Sequence to forecast future precipitation and...