| In recent years,with the acceleration of urbanization and industrialization in China,the role of human activities in the evolution of groundwater environment has become stronger.Under the interference of human activities,the evolution of the original groundwater environment has been destroyed.A series of environmental hydrogeological problems have emerged,which would have a great threat to the ecological environment and human survival.The Yishu Basin is located in the middle of Jilin Province.It is an important grain production base and underground water reserve base in Jilin Province.In recent years,due to the unreasonable exploitation and destruction of human beings,the groundwater level in Yishu Basin has been declining and water quality has been deteriorating.The evolution of the environment is gradually changing from quantity to quality,into the new groundwater environment evolution model.At present,the research on the evolution model of groundwater environment has not been searched.In this paper,the evolution of Quaternary groundwater environment in Yishu basin is discussed,and the evolution model of groundwater environment is defined,classified and analyzed qualitatively and quantitatively.It would provide scientific basis for emergency water sources in the future of the region as Changchun,Jilin and other places.And,it also has a very important theoretical and practical significance on the local economic sustainable development,improvement of the groundwater environment,the overall planning of water resources.Based on the project from the Geological Survey Bureau of China,“the hydrological and geological survey project of Yishu Basin”(1212011089024),there was a special study on the evolution pattern and law of groundwater hydrodynamic and hydrochemistry field under the influence of natural and human activities under the influence of Quaternary groundwater environment in the Yishu Basin.Through the combination of field investigation test and indoor data analysis and research,guided by the technical methods such as Hydrogeology,Geostatistics and Mathematical statistics,the evolution characteristics and laws of groundwater environment were revealed in Yishu basin by the Spatial analysis technology like Map GIS.And,on this basis,the groundwater environment evolution pattern in the study area was analyzed comprehensively.The main research results were as follows:1.Spatiotemporal evolution characteristics of groundwater hydrodynamic field(1)Evolution of Groundwater Level.Based on the field hydrogeological survey and the dynamic monitoring data of the long-term groundwater level in the area,the dynamic curve of the groundwater level,the spatial and temporal zoning map of the groundwater depth and its range were drawn.The results show that the groundwater level in the study area shows a continuous decline trend.And,the phreatic water depth varies greatly with the confined water depth.The variety amplitude in Huapachang-Gudianzi-Moliqing town-Yitong city were greater,which were more than 6m.From 1980 to 1997,the decline of water level was relatively large,but from 1997 to 2014 the range of groundwater level become smaller and the groundwater level has raised in some areas.The temporal and spatial variation of the depth of the phreatic level depth was more affected by the climate change.And,the confined level depth was more affected by artificial mining.(2)Evolution of Groundwater yield.By the water amount equilibrium method,the the amount of groundwater resources was calculated and analyzed.The results show that the amount of groundwater resources varies with the precipitation,and the average groundwater resources is 41419.68 × 104m3/a,in which the atmospheric infiltration recharge accounts for 80% of the total resources;The rank of the groundwater resources modulus of five river basin is that the East Liaohe River Basin <Yitong River Basin <Yinma River Basin <Lalin River Basin <Songhua River Mainstream Basin.The evolution of groundwater resources in the study area is mainly affected by climate change.(3)Evolution Characteristics of Groundwater Circulation Condition.Through the evolution analysis on the groundwater cycle conditions,in natural,the main sources of groundwater recharge are the atmospheric precipitation and the main excretion are river excretion and phreatic evaporation.With the increase of artificial exploitation,the artificial mining has become the main way of excretion.2.Temporal and Spatial Evolution of Groundwater Chemistry Field(1)Evolution Characteristics of Groundwater Chemical Types.Through the Shug Kalev classification method,the temporal and spatial distribution map of the groundwater chemical types was draw.The results show that the main type was HCO3-Ca in 1980s~1990s,which were basically consistent with the distribution characteristics of the natural groundwater chemistry field.In the 2000 s,with the human activities' strongly disturbance,the groundwater chemistry types become more complex and irregular,and the phreatic chemistry types were more complex than the confined water.(2)Evolution Characteristics of Groundwater Chemical Components.According to the dynamic monitoring data of groundwater quality,the dynamic curve and the temporal and spatial distribution of the salinity,total hardness and nitrate in each age were drawn.The results show that from 1984 to 2014 the variation of salinity,total hardness and NO3-was relatively large,which presents an increasing gradually trend overall.But,the overall groundwater quality level was in the category ? standard.And,the NO3-N in some phreatic water samples has exceeded the standard.(3)Evolution Characteristics of Groundwater Quality.The groundwater quality comprehensive pollution index(WQI)was calculated by the formula of groundwater quality evaluation optimized by immune evolutionary algorithm,and the temporal and spatial distribution patterns maps of the groundwater quality were drawn respectively.The results show that the groundwater quality in the study area was excellent than Class III from 1980 to 2000,but,in individual areas the groundwater appeared ? and ? class water.And the confined water quality is slightly better than phreatic water.3.Groundwater environment evolution pattern(1)According to the research on the evolution law of groundwater environment in the study area,the definition of groundwater environment evolution pattern is put forward.And,in terms of the different influence degree from natural factors and human activities,the evolution of groundwater environment is divided into five patterns:(1)Natural factors entirely dominant-Pattern ?;(2)Natural factors dominant,human factors supplement-Pattern ?;(3)Natural and human equilibrium-Pattern ?;(4)Human factors dominant,natural factors supplement-model ?;(5)Human factors entirely dominant-Pattern ?.The development of groundwater environment evolution pattern provides a scientific basis for the future development and utilization of groundwater.(2)The study area contains five river basins.The relationship between climate change,human activities and groundwater environment was analyzed by the gray correlation method.Based on this,the evolution model of groundwater environment in each basin was qualitatively analyzed.From 1980 to 1989,the whole region were mainly effected by the natural factors,and secondary effected by the human activities-Pattern ?;From 1990 to 1999,Yinma river basion and Dongliao river basion was in Pattern ?,but the other river basin were mainly effected by natural and human activities,which present an equilibrium situation – Pattern ?;From 2000 to 2014,the Lalin River Basin was in Pattern ?,the other River Basin were in Pattern ?.(3)In order to further quantitatively study the evolution model of groundwater environment in Yishu basin,according to the established evaluation index system,combined with the stacking index method,fuzzy analytical hierarchy process and Map GIS software,the quantitative analysis of groundwater environment evolution model in three periods were obtained,and the temporal-spatial distribution of the groundwater evolution pattern were draw.The results indicate that in 1980-1999,the study aera was dominated by nature,and supplemented by human activities-Pattern ?,only small area was dominated by nature and human activities – Pattern ?..In 2000-2014,the groundwater evolution was mainly in pattern ? and ?,but in the small area,the groundwater evolution was dominated by human activities,and supplemented by nature-Pattern ?.But,in the study area,the pattern ? have been not yet appeared.Through the study of the evolution pattern of groundwater environment in the study area,it could be used for reasonably planning the intensity of mining activities,coordinating the influence between human and nature on the groundwater environment,which would make the foundation for the sustainable development and utilization of groundwater. |
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