Response Of Taojiang River Basin Runoff To Climate And Land Use Changes Based On SWAT Model

With the continuous development of society,increasingly frequent human activities have led to changes in land use and land cover.The impact of land cover and climate change on watershed hydrological cycle processes has become one of the key hot issues in global change science,watershed hydrology,and other research.In this study,the response of hydrological processes to climate and land use changes in the Taojiang River basin in the upper reaches of the Ganjiang River was studied using a SWAT model.The main work and conclusions of this article are as follows:(1)The SWAT model was established for the Taojiang River basin and its applicability was evaluated.The simulation results showed that the sum of the regular and validation period results for the Julongtan hydrological station was 0.80,0.79,and0.81,0.78,respectively,while the sum of the regular and validation period results for the Dutou hydrological station was 0.86,0.85,and 0.81,0.80,respectively,indicating that the simulation results achieved the application accuracy of the model in the Taojiang River basin,and the effect was good.(2)The distribution of land use types in the two phases of the Taojiang River Basin in 2000 and 2020 was dominated by forest land and cultivated land,respectively accounting for 95.04% and 93.91% of the total area.The high vegetation coverage rate indicates that the vegetation in the Taojiang River Basin is growing well.The changes in land use types and corresponding area values in the Taojiang River Basin in the past20 years are as follows: the proportion of unused land and water area has not changed significantly,the area of forest land has decreased slightly,and the proportion of construction land and grassland area has gradually increased.From 2000 to 2020,land use conversion was relatively frequent.Except for unused land,there were varying degrees of conversion between other land types,with the most severe conversion occurring in grassland.(3)The watershed runoff will be severely weakened by grassland and forest land,while the expansion of cultivated land and construction land will increase the watershed runoff;Compared to the ecological protection scenario,the farmland expansion scenario has a runoff yield advantage,with an annual runoff increase of 5.4%,but compared to the construction and development scenario,the annual runoff decreases by 2.95%.During the high water period,there is a significant difference in runoff production capacity among different scenarios,while during the low water period,there is a small difference in surface runoff among several scenarios.(4)Compared to temperature changes,changes in precipitation have a greater impact on the runoff of the Taojiang River basin.There is a negative correlation between temperature change and annual runoff change.When temperature increases and rainfall decreases,the runoff decreases most.Under the joint action of land use and climate change,the change of watershed runoff is not equal to the simple superposition of two single factors.Land use has a weak impact on runoff change,and climate change has become a key guiding factor for watershed runoff change trends.