Study On The Water Production Effect Of Land Use/Cover Change In Duchang County Based On InVEST Model

Since the 21st century,the impact of human activities on land has become increasingly serious,and the Land-Use and Land-Cover Change caused by it is the leading factor that causes the change of the earth's surface system and regional environment.Land-Use and Land-Cover Change,which is one of the driving forces of ecosystem water yield,has an important impact on regional hydrological process and water resource utilization by changing the properties of underlying surface.With the problems of water shortage,water pollution,flood disaster,soil erosion and so on,the water yield effect of Land-Use and Land-Cover has become a hot issue in the research of global change and hydrological effect,the study of the water yield effects of Land-Use and Land-Cover Change is of great significance to the allocation and management of water resources,development and sustainable utilization,and provides a basis for regional land use planning.This thesis takes Duchang County,Jiangxi Province as the research area,based on the land use data of 2000,2005,2010,2015 and 15 years meteorological data(temperature,precipitation,solar radiation Dem data,soil data,etc.),the InVEST model WaterYield module is used to imitate water yield under different land use patterns in the last 15 years,on the basis of simulating water yield,land use input is changed,and the influence of land use change on water yield in different time period is quantitatively analyzed based on multiple linear regression model.The main findings are as follows:(1)The main types of land use in Duchang County are water area,cultivated land and woodland,the total area of these three types of land use accounts for more than 88%of the total area of the county,in which the area of water area is the largest,accounting for more than 30%of the total area.During the whole study period,the area of cultivated land increased first and then decreased.The area of construction land was increasing,the forest land was"increasing-decreasing-increasing",while the water area was showing a trend of"decrease-increase-decrease",Unused land shows an"increasing-increasing-decreasing"trend.(2)According to the principle of InVEST model and the requirement of data,the processed basic data are imported into InVEST model for parameter verification.When Z=18.90,the simulated water yield is the best with the natural runoff,and the simulation effect is the best.Using the verified model to simulate,the water yield of Duchang County in 2000,2005,2010 and 2015 was 19.61?10~8 m~3,21.70?10~8 m~3,32.76?10~8 m~3 and33.37?10~8 m~3,and the water yield increased year by year.(3)By fixing the meteorological elements at the end of each stage from 2000 to 2005,2005 to 2010,and 2010 to 2015,change the land use input at this stage to obtain the change of water yield in each stage:The water yield under land use in 2005 is 0.17?10~8m~3 more than that under land use in 2000;The water yield under land use in 2010 was0.10?10~8 m~3 less than that under land use in 2005;The water yield under land use in 2015is 0.9?10~7 m~3 more than that under land use in 2010.(4)Based on SPSS 22.0 and 37 subbasins,the multivariate linear regression equations of water yield change and conversion area between different land use types in each sub-watershed were established,the results showed that:Conversion to construction land and cultivated land can promote water production,conversion to forest land and water area to inhibit water production,conversion to unused land can promote both water production and water production.Meteorological factors are the main factors that influence the difference of water yield,but the influence of land use change on water yield can not be ignored,it is of great significance to study the influence of land use change on water resources policy,land planning and ecological planning.