| In the past 30 years,Jiangxi Province has carried out afforestation activities with the theme of“mountains and rivers and lakes”.At the same time,population growth has led to a significant change in the underlying surface.Therefore,the development of a hydrological model assessment of Jiangxi Province as the main research area is conducive to revealing human activities on the basin hydrology.The process impact provides a reference for the planning and management of the river basin.Meteorological data for Poyang Lake Basin together with daily runoff and sediment content measured at hydrological gauges of“Five Rivers”in Poyang Lake watershed as well as Taojiang and Xunwu River were used to simulate over the past30 years with SWAT model.The characteristics of interannual and intra-annual variations explored the effects of three different spatial scales of precipitation on runoff and sedimentation;and analyzed the lands of the“Five Rivers”,the Taojiang and Xunwu catchments of Poyang Lake under different land use scenarios.Using the effects of changes on runoff and sediment,the following main conclusion has been drawn:(1)Under the same meteorological conditions,the land use data of 1980,2000and 2015 were used to simulate the runoff of the Poyang Lake Basin,and it was found that the runoff change trend was not significant under the three different scenarios.Correlation analysis showed that the inner diameter flow in the Poyang Lake Basin was significantly correlated with the precipitation,and the correlation coefficient r of each sub-basin was greater than 0.83.The temperature has a significant effect on the runoff of Poyang Lake Basin,and it is most obvious in summer.(2)Under the two phases of land use scenarios in 1980 and 2015,the runoff and sediment discharge in the Taojiang River Basin were simulated respectively during1981-2013.It was found that the difference between the 2015 scenario runoff and sediment transport amount was only 7.51×10~6m~3 and 2.83×10~3t,the rate of change was 0.12%and 0.20%.Land use change was not the main cause of runoff and sediment changes in the Taojiang River Basin;the simulation results showed that the total sediment interception capacity of the Ju Longtan Water Control Project in the Taojiang River Basin during 2007-2013 was about It is 7.78×10~6t,accounting for 77.5%of the total sediment yield in the Taojiang River Basin.The water conservancy project has a significant impact on the sediment discharge of the Taojiang River.(3)Simulated runoff and silt in the Xunwu catchment under the three land use scenarios of 1990,2000,and 2015.It was found that the runoff and sediment in the2000 land use scenario increased by 3%and 5.28%,respectively.The change has significantly changed the runoff and sand production in the Xunwu watershed.However,runoff and sediment decreased by 0.41%and 0.95%in 2015 compared with2000,which was related to the growth of vegetation in the orchards and the restoration of underlying surfaces.(4)The large-scale reservoir artificial regulation has a greater impact on the repair and runoff,leading to poor runoff simulation results,and further acquisition of the reservoir's scheduling data to obtain better simulation results;the sediment simulation accuracy of Xuowu watershed is low,and the verification period is Ens The coefficient is only 0.68.Due to the large planting area in orchards in the Xwu River basin,it is necessary to establish a SWAT land database for orchards in the basin.(5)The hydrological and silt modeling of watersheds in different spatial scales shows that land use at large and mesoscale is not an important factor affecting the runoff and sediment changes;from the simulation results of the Xunwu catchment,the scale of human activities Runoff in river basins and river sediment transport can have significant effects. |
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