| Water resource is an important source of life.With the development of science and technology,water resource has a new meaning.Water resources are always related to human life and health,economic development,urban and rural development and the maintenance of ecological system.At present,the water resource problem is severe,drought and flood disasters are frequent,fresh water resources shortage,the contradiction between supply and demand is prominent,seriously affecting human life.Land use and climate change are important factors affecting hydrological response.Land use change and climate warming caused by intensified human activities seriously affect water availability.Due to climate,terrain and history,drought and flood disasters occur frequently in huaihe River basin.Climate warming and precipitation distribution pattern of "flood in the south and drought in the north" lead to extremely fragile water resources system in the Huaihe River Basin [1].Therefore,studying the hydrological response of land use and climate change can understand the main influencing factors of hydrological processes in the basin,explore the influencing mechanism of hydrological response,promote the sustainable development of water resources,and have important guiding significance for the evaluation,allocation and management of water resources and the rational planning of land use.With the continuous integration of GIS,remote sensing and other new-generation information technologies with traditional hydrological models,distributed hydrological models are developing rapidly.People are no longer satisfied with summarizing the hydrological response of a basin as a whole,but require more refined hydrological cycle simulation.However,most current studies consider the impacts of land use and climate change on hydrological processes at the scale of the whole basin,with little consideration of the temporal and spatial heterogeneity of impacts.However,these are the basis for understanding the cycle mechanism of hydrological processes within the basin,and are crucial for scientific management of hydrology and hydrological resources.The extreme hypothetical scenario and future scenario are used to predict the hydrological response of land use and climate change in the future.However,the temporal segmentation method is only used to analyze the influence of historical environmental change on runoff,and the hydrological response includes the influence of other factors.To solve these problems,this paper takes the upper reaches of the Huaihe River Basin as the research area,and uses the historical measured data from 1984 to 2015 to drive the SWAT model.Through calibration and verification,the simulation accuracy is high,and the hydrological cycle process in the upper reaches of huaihe River basin is further simulated.The trends of historical land use,climate and runoff in the upper reaches of huaihe River basin were compared and analyzed.Using the linear trend interference method with historical measured data to generate two sets of climate drive data,combined with the history of land use data set a variety of simulation scenario,to explore the land use,climate and hydrological response of the comprehensive change scenario,reveal the influence of the hydrological response mechanism,compare the land use and the relative contribution of climate change on hydrological response and precipitation and temperature sensitivity.The main results are as follows:1)From 1990 to 2015,the land use change at the whole watershed scale was small,but the land use change at the sub-watershed scale was relatively significant.During the historical period from 1984 to 2015,the measured precipitation showed a decreasing trend,while the measured temperature showed an increasing trend.The monthly runoff data showed no significant decreasing trend on the whole.2)The NS value,R2 and PBIAS of THE SWAT model were 0.90,0.92 and 8.4,respectively,and the NS value,R2 and PBIAS of the VALIDATION period were 0.90,0.91 and-1.2,respectively,proving that the selected sensitivity parameters can further simulate the hydrological cycle process in the upper reaches of the Huaihe River Basin.3)The hydrological responses at the whole basin scale and sub-basin scale are significantly different,and the hydrological responses at sub-basin scale have significant spatial heterogeneity.In the case of land use change,the change of land use at the whole watershed scale is small,and the change of hydrological response is not obvious,but the hydrological response of sub-watershed and some sub-watershed is very significant.In the climate change scenario,the hydrological response changes significantly at the whole watershed scale,but not at the partial watershed.4)Comprehensive change scenarios have an enhanced or weakened effect on hydrological response.At the whole basin scale,the hydrological response of the basin was weakened under the comprehensive change scenario.At the sub-watershed scale,the hydrological response of partial and sub-watershed weakened,while that of partial and sub-watershed strengthened.Comprehensive change scenarios integrate the effects of land use change and climate change,but the effects of comprehensive change on hydrological response are not linear.5)Different hydrological factors have different responses to environmental changes.In the same subbasin with the same environmental change,some hydrological factors changed significantly,while others did not. |
