Flood control risk analysis based on Integrated Time-Varying Moment model and Dynamic Monte Carlo method
Compared with the historical hydrological situation that serves as the basis for the design of water conser-vancy and hydropower projects,the situation affected by global climate change in future will deviate from it.This will lead to changes of hydrological analysis results of runoff and design floods.As a result,the changes will affect the long-term operation safety and flood control of cascade reservoirs in the basin.This study takes the Yalong Riv-er basin as the research area,and quantitatively identifies the changes in meteorological and hydrological elements of the basin under future climate change conditions through coupling the SWAT hydrological model and global cli-mate model.Based on this,an Integrated Time-Varying Moment(ITVM)model that can consider non-stationarity and historical extraordinary floods(HEFs)information jointly is proposed to carry out the non-stationary frequency analysis.Finally,the flood control risk assessment of the Yangfanggou hydropower station un-der future climate change conditions is conducted based on the Dynamic Monte Carlo(DMC)method.The main re-sults are as follows:the calibrated SWAT model has high simulation accuracy and good spatial applicability in the Yalong River Basin.Under the future climate change conditions,the peak flow series of Maidilong station increases slightly from now to around 2070 under the SSP 1-2.6 scenario,followed by a slight decrease;Under the SSP2-4.5 scenario,it increases from now to around 2070 significantly,and then tends to stabilize;Only in the SSP5-8.5 scenario it continues to rise,and the upward trend is obvious.Under future climate change conditions,except for the risk of exceeding the design flood level under the SSP 1-2.6 scenario,the risk of exceeding the design flood level and check flood level of Yangfanggou Hydropower Station have significantly increased compared to the design standards.Future global climate change will have a significant impact on the water cycle and land-air water ex-change in the Yalong River basin,leading to more severe hydrological extreme events.The hydropower stations(reservoirs)planned and constructed in the basin based on the hydrological analysis results in stable environment will face greater flood control risks.The flood control risk analysis method integrating the ITVM and DMC model proposed in this article can consider the effects of HEFs and the non-stationarity of flood series caused by future global climate change together,and it has been verified to have good applicability in practice.The results can pro-vide certain references for the relevant management institutions to deal with flood control risks and guide actual pro-duction.
climate changenon-stationarityintegrated time-varying moment modelflood control risks
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