Infiltration Variation Analysis Based On LUCC In The Western Of Jilin Province

Water resources problems in Semi-arid area has long been bothering the scientific researchers,during the past half century,large quantity of land has been exploited,thus the form of the land use changed. As water scarcity exists,it is crucial to ascertain the land use change effect to the water quantity.Relative research has been done about surface water and ground water,which were dedicated in their quantity,quality problems,but infiltration problem is usually ignored,because different land use type and its ability to keep infiltration,thus infiltration changes correspondingly.Infiltration meanwhile is the main source of the groundwater,it occupies 84.7%of the ground water,and can serve for the growth of the plants,thus is the key point of water cycle.Based on the above reasons,we should pay special attention to the infiltration change which relates to land use change.Western part of Jilin Province,due to its long term special semi-arid climate,has driven the low infiltration tendency toward extremity,thus if we try to calculate the land use change by the traditional methods,then it will cause great burden to the researchers.Under this circumstance,with the aid of the more and more used GIS technique,the workload will greatly be relieved,errors will be eliminated and accuracy will rise.The paper uses ArcGIS,ERDAS to interpret TM images of western part of Jilin Province,to analyze the land use situation between 1989-2004,statistics show that paddy field has increased 114200hm~2 with the accelerating speed of 6.75%/a,which is the fastest,Saline soil is the second largest land use type,it increased 256700hm~2,the speed of which is the highest.Wetland has decreased 14200hm~2,decreasing rate of which is 4.18%/a.Saline's roaring increase,marsh,water field's sharply decrease and pasture's degradation has shown the landscape has changed.Based on the international cases' analysis and the research area situation,SWAT is chosen to estimate the infiltration of the research area.Data analysis, field investigation would help in the database building.Matlab is put into application to obtain the mechanisms of soil data and SPAW is used to calculate the attributes of the soil data and build the database.Climate data can be downloaded on the shared websites and then would be converted in to the format needed.Arcview is utilized with its AV-SWAT extension to load the database,time step will be measured yearly.The modeling results show that in the year 2004 the average infiltration is 50.211mm, about 0.22 billion m~3,while by calculation methods the infiltration in the year 2004 is 60.9mm,10.7mm more than the modeling.After the calibration of the traditional and model methods,the fitness of SWAT will be testified.The final part of the paper had predicted the infiltration change in the future,after the calibration of the infiltration in the year 2004,the accuracy of the model will be figured out,and import the predicted 2019 land use to model the infiltration,results show that in infiltration will decrease from 53.48mm to 45.21mm,thus will cause effect to the ground water recharge.LUCC and its effect to the groundwater recharge has become the international research front area,this paper has only calculated and analyzed the infiltration,and the tendency is to combine the hydraulic model and "3S" technique to solve the problems.