Flow regime changes in three catchments with different landforms following ecological restoration in the Chinese Loess Plateau  

作　　者：LUO Zhidong LIU Erjia QI Shi ZHAO Nan SUN Yun 

机构地区：[1]College of Soil and Water Conservation,Beijing Forestry University,Beijing 100083,China [2]Water and Soil Conservation Monitoring Center of Ministry of Water Resources,Beijing 100053,China [3]Key Laboratory of Soil and Water Conservation of State Forestry Administration,Beijing 100083,China [4]Engineering Research Center of Forestry Ecological Engineering,Ministry of Education,Beijing 100083,China [5]Shanxi Institute of Soil and Water Conservation,Taiyuan 030045,China

出　　处：《Journal of Arid Land》2020年第1期44-57,共14页干旱区科学（英文版）

基　　金：funded by the National Key Research and Development Program of China(2016YFC0503705)

摘　　要：The Chinese Loess Plateau is known as one of the most severe soil erosion regions in the world.Two ecological restoration projects,i.e.,the integrated soil conservation project since the 1970s and the''Grain for Green''project since 1999,have been progressively implemented to control the soil erosion in this area.Ecological restoration has greatly changed flow regime over the past five decades.However,the mechanism of how flow regime responds to ecological restoration among landforms remains poorly understood.In this study,we investigated the temporal dynamics of flow regime in three catchments,i.e.,Wuqi,Honghe and Huangling hydrological stations,respectively representing the loess hilly-gully,loess table-gully and rocky mountain(covered by secondary forest)areas in the Chinese Loess Plateau,using daily hydrological data during the 1960s–2010s.The nonparametric Mann-Kendall test,Pettitt's test and daily flow series were used to investigate the changes of flow regime.Significantly negative trends of annual streamflow were detected at the Wuqi and Honghe stations,except for the Huangling station.The annual baseflow at the Wuqi station showed a significantly positive trend whereas a significantly negative trend was observed at the Honghe station,and there was no significant trend at the Huangling station.It was interesting that baseflow index significantly increased during the whole period in all catchments.However,the trends and change points of daily flow series derived by different percentages of exceedance and extreme series in different consecutive days varied among individuals.Based on the change points analysis of annual streamflow,we divided data series into three periods,i.e.,the baseline period(from 1959 and 1963 to 1979,PI),the integrated soil conservation period(1980–1999,PII)and the''Grain for Green''period(2000–2011,PIII).We found that streamflow decreased due to the reduction of high streamflow(exceeding 5%of time within a year)and median streamflow(50%)in PII and PIII at the Wuqi and Honghe staThe Chinese Loess Plateau is known as one of the most severe soil erosion regions in the world. Two ecological restoration projects, i.e., the integrated soil conservation project since the 1970 s and the ’’Grain for Green’’ project since 1999, have been progressively implemented to control the soil erosion in this area. Ecological restoration has greatly changed flow regime over the past five decades. However, the mechanism of how flow regime responds to ecological restoration among landforms remains poorly understood. In this study, we investigated the temporal dynamics of flow regime in three catchments, i.e., Wuqi, Honghe and Huangling hydrological stations, respectively representing the loess hilly-gully, loess table-gully and rocky mountain(covered by secondary forest) areas in the Chinese Loess Plateau, using daily hydrological data during the 1960 s–2010 s. The nonparametric Mann-Kendall test, Pettitt’s test and daily flow series were used to investigate the changes of flow regime. Significantly negative trends of annual streamflow were detected at the Wuqi and Honghe stations, except for the Huangling station. The annual baseflow at the Wuqi station showed a significantly positive trend whereas a significantly negative trend was observed at the Honghe station, and there was no significant trend at the Huangling station. It was interesting that baseflow index significantly increased during the whole period in all catchments. However, the trends and change points of daily flow series derived by different percentages of exceedance and extreme series in different consecutive days varied among individuals. Based on the change points analysis of annual streamflow, we divided data series into three periods, i.e., the baseline period(from 1959 and 1963 to 1979, PⅠ), the integrated soil conservation period(1980–1999, PⅡ) and the ’’Grain for Green’’ period(2000–2011, PⅢ). We found that streamflow decreased due to the reduction of high streamflow(exceeding 5% of time within a year) and

关 键 词：change point extreme series hydrological data soil erosion streamflow changes 

分 类 号：X171.4[环境科学与工程—环境科学]