| Climate and underlying surface are two important factors affecting the hydrological cycle.The climate mainly affects the hydrological cycle through temperature,rainfall,evapotranspiration,etc.The underlying surface mainly affects the hydrological cycle through the interception,infiltration and evapotranspiration of precipitation.Since entering the industrial civilization,along with the prosperity of industrial and agricultural production activities,greenhouse gas emissions have increased sharply,causing climate change characterized by global warming.At the same time,it is superimposed by the expansion of impervious surface caused by high-speed urbanization in China.The change of the underlying surface has led to profound changes in the characteristics of hydrological cycle and water resources in China,causing a series of water resources problems such as drought,flood and guilt.In this paper,the HSPF model is applied to the upper reaches of the Weishui River Basin to study the runoff response of climate change and impervious surface expansion,in order to reveal the change law of upstream runoff in the watershed under the background of climate change and impervious surface expansion and provide reference for water resources management in the basin.Based on the upstream DEM data in the Weishui River Basin,the upstream digital river network in the Weishui River Basin is extracted and divided into 23 sub-basins.On this basis,a total of 282 hydrological units were divided by underlying surface heterogeneity and meteorological heterogeneity.The applicability is evaluated by the correlation coefficient R2 and the Nash efficiency coefficient ENS.the correlation coefficient of the calibration period is 0.92,the Nash efficiency coefficient ENS is 0.85,the correlation coefficient of the verification period is 0.97,and the Nash efficiency coefficient is 0.90,indicating that the HSPF model is applicable in the study area.This paper simulates the runoff process under the upstream impervious surface expansion scenarios and climate change scenarios in the Weishui River Basin.The simulation results show that under the scenario of impervious surface expansion in the study area from 2000 to 201 5,when the impervious rate increased from 1.4%to 3.5%,the average annual runoff increased by 1.76%;the impact of impervious surface expansion on runoff during dry season is greater than that on runoff during flood season;In typical hydrological years,the impervious surface expansion has the greatest impact on the annual runoff depth of dry water year,followed by the flat water year and the smallest water year;Under the scenario of impervious surface expansion in the main urban area from 2000 to 2015,the impervious rate of the main urban area increased from 10.25%to 42.75%,and the new impervious surface area in the main urban area accounted for 70%of the newly-impermeable impervious area of the study area.The impact of the impervious surface expansion of the urban area and the study area on runoff is consistent,but in the extent of impact,the main urban area is larger than the study area.In this paper,the trend and mutation analysis of rainfall and temperature data in the upper reaches of the Weishui River Basin from 1980 to 2012 show that the climate of the study area has changed.Based on the data of known climate research results,the runoff response of climate change is studied.The results show that under the climate change scenario,the RCP4.5 medium-concentration greenhouse gas emission model has much less impact on the runoff depth of the study area than the RCP8.5 high concentration greenhouse gas.Under the RCP4.5 medium-concentration greenhouse gas emission model,the runoff depth of each scenario is deeper than the baseline period.The growth rate range is-2.42%-1.43%,and the RCP8.5 high concentration greenhouse gas Under the emission mode,the runoff depth of each scenario is deeper than the baseline period and the growth rate ranges from-14.57%to?1.84%. |
PDF Full Text Request