Study On Ecological Flow Protection For Shayinghe River Basin Under Land Use/Cover Change

The Shaying River is the largest primary tributary in the Huaihe River Basin.It is an important source of water for navigation and agricultural irrigation for the Huaihe River Basin in the history,so maintaining its ecological environment is crucial for the economic development of the Shaying River Basin and the downstream of Huaihe River.However,with the rapid development of human society,the construction of dams,Water withdrawals outside the river,the increasing intensity of human activities and climate change have led to serious changes in the river’s hydrological situation.The reason is that the river’s ecological flow cannot be guaranteed.In this paper,we selected the SWAT distributed hydrological model to simulate the key section runoff in the Shaying River Basin under different land use scenarios based on the analysis of the main meteorological and hydrological factors of the Shaying River to explores the key section ecological flow under different land use patterns.The final conclusion was as follows:（1）Based on the overview of the Shaying River Basin,on the basis of identifying the key sections of the Zhoukou and Fuyang of Shaying River Basin,daily hydrologic series of Zhoukou Hydrological Station and Fuyang Hydrological Station from 1990 to 2010 were selected,the IHA（Indicators of Hydrologic Alteration,IHA）parameters were calculated using the software IHAV7.1,the ecological flow of the key sections of the Zhoukou and Fuyang,Shaying River are calculated based on the range of variability approach RVA.（2）The distributed hydrological SWAT model of the Shaying River Basin was set up using DEM data,soil dataset（HWSD）,land use data,meteorological data,hydrological data.The daily runoff of two hydrological stations of the Zhoukou and Fuyang was simulated.Nash-Sutcliffe efficiency coefficient（Ens）and determination coefficient（R²）were used as evaluation indexes,and 11 sensitive parameters that have important effects on runoff were picked from 28 parameters that have an impact on runoff by SUFI-2mothed using SWAT-CUP.The results show that the efficiency coefficient Ens and the decision coefficient R²are 0.87 and 0.80,respectively,and the daily runoff from 1990 to2010 was verified.Based on the parameter sensitivity analysis,the model was validated by using the boundary first and Zhoukou flow monitoring data.The results show that the model can meet the accuracy requirements and has good applicability in the Shaying River Basin.It can be used to analyze the impact of land use/cover change on runoff.（3）Land cover data from 1990,2000 and 2010 were brought into the calibrated SWAT model to simulate runoff.Overall trendency of runoff was 2010>2000>1990.The contribution coefficients of four types of land cover types such as cultivated land,forest land,grassland and construction land to runoff are calculated as-1.18 m³/s·km^-2,3.43m³/s·km^-2,-1.41 m³/s·km^-2,1.24 m³/s·km^-2using Matlab.（4）Four kinds of land cover scenarios were set up,and the distributed hydrological SWAT model was set up by using the measured meteorological data from 2006 to 2015.The results were as follows:the Nash coefficient Ens and the correlation coefficient R²are0.87 and 0.85,respectively.The model was validated by using the daily measured runoff data from Fuyang Hydrological Station in 2010-2012.Simulating the monthly runoff variation of the Shaying River Basin under four land cover changes,and coupling the above-mentioned ecological flow based on the hydrological variation RVA method and the RVA threshold to calculate the key sections of the Shaying River of Zhoukou and Fuyang,and identifying the key sections under different land use scenarios.The ecological flow guarantee situation and the selection of the optimal land use scenario provide technical support for the Shaying River land use planning,management and ecological flow protection.