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Accueil du site → Doctorat → Chine → 2017 → Modeling Hydrological Responses to Ecological Restoration in the Upper Reaches of Beiluo River Basin,Loess Plateau,China

Northwest A&F University (2017)

Modeling Hydrological Responses to Ecological Restoration in the Upper Reaches of Beiluo River Basin,Loess Plateau,China

闫瑞;

Titre : Modeling Hydrological Responses to Ecological Restoration in the Upper Reaches of Beiluo River Basin,Loess Plateau,China

Auteur : 闫瑞;

Grade : Doctoral Dissertation 2017

Université : Northwest A&F University

Résumé partiel
Loess Plateau belongs to a semi-arid climate region with the characteristics of unevenly distributed water resources and transitivity between the soil,climate and vegetation,which also lead to the results of destroyed vegetation,broken landform and loess soil in the Loess Plateau.Hence,the area gradually became one of the most serious soil erosion regions in the world.In order to prevent the soil erosion,a series of soil and water conservation measures were implemented,which lead to that the land use/ cover obviously changed and impacted the ecosystem,the climate change,hydrology and water resources in the Loess Plateau.These changes attracted many scholars attention in various research field.Therefore,the upper reaches of Beiluo River Basin was selected as research area in this study.The methods including sliding average,Sen Slope and Mann-Kendall test were selected to analyze the changing trends of meteorological and hydrological data.The Landsat TM imagine data were employed and the vegetation coverage were derived to analyze how the vegetation restored and the trends of vegetation distribution on the landform.Based on land use maps in the year of 1995,2000 and 2010 combined with RS and GIS,digital watershed model was established and quantitatively analyzing the contribution from land use/cover change and climate change to the variation of runoff.And the changed trend of runoff,evapotranspiration and soil water content were analyzed.The temporal and spatial variation of soil erosion were also analyzed based on that database.In the end,according to the different land use and climate scenarios,the hydrological responses were analyzed.The main conclusions were as follows :(1)Precipitation of the upper reaches of Beiluo River Basin from 1963-2012 nonsignificantly increased and the annual increment was 0.45 mm.The annual average precipitation was 439.33 mm.The changed period of precipitation were roughly divided into three period during the 50 years.From 1963 to 1978,the year was non-significant decreasing,and the linear trend was-2.3 mm·a-1.The average annual precipitation was 416.9mm.From 1979 to 2001,the year was non-significant increasing period,and the linear trend was 0.2 mm·a-1.From 2002 to 2012,the year was decreasing period,and the linear trend was-0.4 mm·a-1.(2)The Mann-Kendall method was selected to analyze the change trend of runoff and sediment.The results showed that the runoff and sediment obviously decreased(P<0.05),and the average annual variability were-0.32mm·a-1 and-170.18 t·km-2·a-1,respectively for runoff and sediment.The change trend of annual runoff from 1963 to 2012 can be divided into three stages.From 1963 to 1978,the annual runoff slowly decreased,and the linear trend was-0.9mm·a-1.From 1979 to 2001,the annual runoff gradually increased,and the linear trend was 0.3 mm·a-1.From 2002 to 2012,the annual runoff obviously increased,and the linear trend was-0.7 mm·a-1 at a significant levele of P<0.05.The change trend of annual sediment load from 1963 to 2012 also was divided into three stages.From 1963 to 1978,the annual sediment load slowly decreased,and the linear trend was 10375.1 t·km-2·a-1.From 1979 to 2001,the annual sediment load gradually increased,and the linear trend was 10375.1 t·km-2·a-1.From 2002 to 2012,the annual sediment load obviously increased,and the linear trend was 148.9 t·km-2·a-1 at a significant levele of P<0.05.(3)Since 1999,the implementation of the Grain for Green project was successful in improving the vegetation coverage in the study area.The changes in land use types at the three years are calculated

Mots clés : Runoff and sediment; Model simulation; Climate change; Grain for Green Project; Loess Plateau;

Présentation (CNKI)

Page publiée le 21 janvier 2018