Study On Ecological Groundwater Level And The Amount Of Regulation In Plain Region Of Western Jilin Province

Groundwater is one of the support elements of the ecological environment. It is theregulator to maintain the Earth's shallow water, salt, heat balance and the biodiversity.Any kind of plants for water, salt, heat has its own optimal threshold and endurancelimit. Therefore, appropriate water level (phreatic level) is the important condition formaintaining the stability of vegetation communities. Especially in arid, semi-arid areas,surface ecological and groundwater levels are closely related.The west plain of Jilin was selected as the scope of the study. We analyzed thegroundwater dynamic changes in characteristics and the main factors and determined thereasonable groundwater ecology water level through a variety of technical methods inWest plain of Jilin area. Thus the result can guide the rational development of groundwaterresources, keeping groundwater level at a reasonable range, maintaining the normal growthof the plants, reducing the risk of secondary salinization and desertification and promotingthe coordinated development of socio-economic and ecological environment.(1) On the basis of summarizing the natural and geological conditions of study area, we deeplyanalyzed the nearly 10 years of temporal and spatial variation of groundwater level from2000 to 2009 using Kriging method. And analyzed and discussed the factors of effect thetemporal and spatial variation of groundwater table using stepwise regression method.(2) Using the collected data, we analyzed the exploitation and utilization ofgroundwater in the study area in recent years. Then, taking multi-year average of therecharge as groundwater resources, we determined the appropriate exploitation ofgroundwater by calculating.(3) Through field investigations and laboratory experiments, we established soiltexture, land use type and groundwater salinity data layers using the geographicinformation (GIS) technologies in the study area. The type of soil and water of the studyarea has been divided through overlay analysis. According to the data of groundwater andevaporate intensity in different locations within the study area, we determined that theecological water level threshold was equal to the limit evaporation depth. According to the different areas vegetation root layer thickness and height of capillary rise, taking intoaccount the salinity of groundwater, we determined that the ecological water levelthreshold was equal to the sum of vegetation root thickness and capillary rise high. And thedistribution of appropriate zone of groundwater ecological water level and groundwatersurplus area and deficit area were delimited.(4) Using ArcGIS software of drawing, and calculation function, we made thegroundwater status actual buried deep and groundwater ecological water level ceiling andlower to the dem file. Calculation of the area and volume of groundwater deficit andexcess with the MINUS tools and filled dug tools. Then make the volume multiplied bythe specific yield, to get the amount of regulation of groundwater level return to theappropriate zone.