Study On The Temporal And Spatial Change Of Groundwater Based On Spatial Interpolation Model--Take Qitai Oasis As Example

Groundwater is not only a precious resource but also the one of important factors that affects the overground ecosystem. Groundwater's change often causes unbalance and damage to the whole ecological environment. In the world, overexploiting groundwater and making the level descend can induce four environmental and geological problems: regional growdwater filler, ground fall, seawater intrusion and water quality aggravation and so on. Overexploiting groundwater makes the groundwater level of superficial layer descend greatly, which dries the original swamp and wetland. Thus water-grown vegetation and water foul disappeared and the intrinsic landscape was damaged. In arid area, the great falling of superficial layer's groundwater can make the oasis desert. Similarly, overexploiting deep groundwater in loose deposit can also make groundwater level fall, forming regional groundwater filter and ground-descending disaster. In littoral area or that with ground brine, overexploiting groundwater will cause seawater or brine intrude groundwater and make the water quality deteriorate, which reduces the usable groundwater resource and affects agriculture production and people lives seriously.Based on research of predecessor, this thesis takes Qitai Oasis as research area that has the serious problem of overexploiting groundwater. After analyzing such hydrological geology as dynamic features of groundwater, according to the actual condition of research area, adopted the methods of GIS and spatial interpolation to discuss the problems, expecting to find some new rules in the research of groundwater dynamic change.The main contents are as follows:First, according to the features of each stage, analyzing the condition of groundwater burial depth, combined with runoff, rainfall, evaporation and water quality, the thesis finds the main factor affecting the groundwater burial depth of oasis.Second, based on data and investigation, combined with hydrologygeology features there and GIS data processing and simulated technology, the thesis analyzed the groundwater level features and development trend in recent 20 years of Qitai Oasis, expecting to grasp the law of groundwater dynamic change.Third, according to the law of groundwater dynamic change, find the best way for groundwater exploit and use, and put forward the suggestions and ideas to use groundwater reasonably.Draw the following conclusions by the above discussion.First, seeing from the spatial, the groundwater burial depths of piedmont change little and even rise. This change seems obvious against the whole research area where water levels descend.Second, the change multitude of the vicinity around the core area change violently, and it appears the tendency of reducing each year. The reason of this change is apparently from that of groundwater in front mountain. The thesis primarily indicates that with the increase of agriculture water inside the oasis, the descend of groundwater falls further.Third; other places do not change very greatly from temporary and spatial compared with the important exploit places with Qitai County as core area which shows that groundwater exploit of these places are weak than that of oasis core area and also shows that the agriculture activities of these places develop slowly. Meanwhile, the groundwater level descending takes the look of diffuse towards two branches of oasis core.Fourth, seeing from the change speed of groundwater burial depth, it grows faster with different period of time.Fifth, the thesis analyzed the influence factor affecting groundwater burial depth of Qitai Oasis by correlation analysis, drew the conclusion that human being exploit is the leading factor causing the groundwater burial depth to change. Moreover, the thesis analyzed and discussed the driving force for the above change.