Assessment report of the Intergovernmental Panel on Climate Change （IPCC） highlighted the complex linkages between climate change and water. The likely warmer climate induced by the climate change is set to alter hy...Assessment report of the Intergovernmental Panel on Climate Change （IPCC） highlighted the complex linkages between climate change and water. The likely warmer climate induced by the climate change is set to alter hydrological cycle and the shifting pattern of the rainfall would affect the spatial and temporal distribution of runoff, soil moisture, and surface and groundwater reserves. Therefore, there is an urgent need to assess the impacts of climate change on water and devise adaptation measures including management structures and processes by which one can deal with this challenge. The paper highlights with the global overview of climate change impacts on water in the arid region, supported and substantiated through scientific evidence drawn from IPCC reports and other relevant documents. This paper provides an overview of water resource management challenges including transboundary geopolitical concerns documented across the world and emphasizes the importance of an integrated framework for adaptive policy making. Further, it examines the viable water resource management options for various sectors and regions and showcases some of the international best practices in adaptation and mitigation. The paper also explains the complementary role of traditional knowledge in coping with climate change risks and uncertainties and the need for a balanced view in designing adaptation and mitigation strategies.展开更多
Rainfall,runoff (surface runoff,interflow and groundwater runoff) and soil loss from 5 m × 15 m plots were recorded for 5 years (2001-2005) in an experiment with three treatments (cover,mulch and bare ground) on ...Rainfall,runoff (surface runoff,interflow and groundwater runoff) and soil loss from 5 m × 15 m plots were recorded for 5 years (2001-2005) in an experiment with three treatments (cover,mulch and bare ground) on sloping red soil in southern China.Surface runoff and erosion from the Bahia grass (Paspalum notatum Flugge) cover plot (A) and mulch plot (B) during the 5 years were low,despite the occurrence of potentially erosive rains.In contrast,the bare plot (C) had both the highest surface runoff coefficient and the highest sediment yield.There were significant differences in interflow and surface runoff and no significant difference in groundwater runoff among plots.The runoff coefficients and duration of interflow and groundwater runoff were in the order plot B > plot A > plot C.Effects of Bahia grass cover were excellent,indicating that the use of Bahia grass cover can be a simple and feasible practice for soil and water conservation on sloping red soil in the region.展开更多
The Badain Jaran Desert exhibits the greatest difference in altitude of all of the world's deserts.On the slopes of megadunes in the desert,there are physical and chemical deposits produced by surface runoff.In ad...The Badain Jaran Desert exhibits the greatest difference in altitude of all of the world's deserts.On the slopes of megadunes in the desert,there are physical and chemical deposits produced by surface runoff.In addition,we have observed rarely-seen infiltration-excess surface runoff in the megadune depressions as well as spring streams at the base of megadunes.We used electron microscopy,energy spectrum analysis,infiltration experiments,moisture content determinations and grain-size analysis to study the mineral and chemical composition of the runoff precipitates,and grain-size of the deposits associated with the runoff,together with the hydrological balance in the megadune area,and the atmospheric precipitation mechanism responsible for groundwater recharge and for supplying water to lakes.The observations of shallow runoff and infiltration-excess surface runoff indicate the occurrence of strong and effective precipitation in summer,which would provide an important source for groundwater recharge.Several lines of evidence,such as the physical and chemical deposits resulting from shallow subsurface runoff,spring streams,infiltration-excess runoff,and gravity capillary water with a moisture content of 3-6%,demonstrate that precipitation reaches the base of the megadunes through infiltration and subsequently becomes groundwater.The chemical deposits,such as newly-formed calcite and gypsum,and gray-black physical deposits,as well as different stages in the development of fan-shaped landforms resulting from shallow subsurface runoff,indicate that groundwater recharge in the area is the result of long-term precipitation,rather than intermittent individual major rainfall events.Fine sand layers with a low infiltration capacity lead to subsurface runoff emerging at the ground surface.Five factors play an important role in maintaining a positive water balance and in replenishing groundwater via rainfall:effective rainfall as a water source,the high infiltration capacity of the sands enabling rainfall to rapidly become capillary water in the dunes,low evapotranspiration rates due to the sparse vegetation,the fact that the depth of the sand layer influenced by evaporation is shallow enough to maximize the deep infiltration of rainfall,and rapidly-moving gravity capillary water in the sandy dunes.These five factors together constitute a mechanism for groundwater recharge from rainfall,and explain the origin of the groundwater and lakes in the area.Our findings represent a significant advance in research on the hydrological cycle,including groundwater recharge conditions and recharge mechanisms,in this desert region.展开更多
文摘Assessment report of the Intergovernmental Panel on Climate Change （IPCC） highlighted the complex linkages between climate change and water. The likely warmer climate induced by the climate change is set to alter hydrological cycle and the shifting pattern of the rainfall would affect the spatial and temporal distribution of runoff, soil moisture, and surface and groundwater reserves. Therefore, there is an urgent need to assess the impacts of climate change on water and devise adaptation measures including management structures and processes by which one can deal with this challenge. The paper highlights with the global overview of climate change impacts on water in the arid region, supported and substantiated through scientific evidence drawn from IPCC reports and other relevant documents. This paper provides an overview of water resource management challenges including transboundary geopolitical concerns documented across the world and emphasizes the importance of an integrated framework for adaptive policy making. Further, it examines the viable water resource management options for various sectors and regions and showcases some of the international best practices in adaptation and mitigation. The paper also explains the complementary role of traditional knowledge in coping with climate change risks and uncertainties and the need for a balanced view in designing adaptation and mitigation strategies.
基金Supported by the National Natural Science Foundation of China (Nos. 40830640 and 41071026)the Plan for Innovation of Graduate Students of Jiangsu Province,China (No. CX09B_168Z)
文摘Rainfall,runoff (surface runoff,interflow and groundwater runoff) and soil loss from 5 m × 15 m plots were recorded for 5 years (2001-2005) in an experiment with three treatments (cover,mulch and bare ground) on sloping red soil in southern China.Surface runoff and erosion from the Bahia grass (Paspalum notatum Flugge) cover plot (A) and mulch plot (B) during the 5 years were low,despite the occurrence of potentially erosive rains.In contrast,the bare plot (C) had both the highest surface runoff coefficient and the highest sediment yield.There were significant differences in interflow and surface runoff and no significant difference in groundwater runoff among plots.The runoff coefficients and duration of interflow and groundwater runoff were in the order plot B > plot A > plot C.Effects of Bahia grass cover were excellent,indicating that the use of Bahia grass cover can be a simple and feasible practice for soil and water conservation on sloping red soil in the region.
基金supported by the Major Projects of International Cooperation of National Natural Science Foundation of China(Grant Nos.41210002 & 40672108)the Cheung Kong Scholars Programme of the Ministry of Education of China(Grant No.801813)
文摘The Badain Jaran Desert exhibits the greatest difference in altitude of all of the world's deserts.On the slopes of megadunes in the desert,there are physical and chemical deposits produced by surface runoff.In addition,we have observed rarely-seen infiltration-excess surface runoff in the megadune depressions as well as spring streams at the base of megadunes.We used electron microscopy,energy spectrum analysis,infiltration experiments,moisture content determinations and grain-size analysis to study the mineral and chemical composition of the runoff precipitates,and grain-size of the deposits associated with the runoff,together with the hydrological balance in the megadune area,and the atmospheric precipitation mechanism responsible for groundwater recharge and for supplying water to lakes.The observations of shallow runoff and infiltration-excess surface runoff indicate the occurrence of strong and effective precipitation in summer,which would provide an important source for groundwater recharge.Several lines of evidence,such as the physical and chemical deposits resulting from shallow subsurface runoff,spring streams,infiltration-excess runoff,and gravity capillary water with a moisture content of 3-6%,demonstrate that precipitation reaches the base of the megadunes through infiltration and subsequently becomes groundwater.The chemical deposits,such as newly-formed calcite and gypsum,and gray-black physical deposits,as well as different stages in the development of fan-shaped landforms resulting from shallow subsurface runoff,indicate that groundwater recharge in the area is the result of long-term precipitation,rather than intermittent individual major rainfall events.Fine sand layers with a low infiltration capacity lead to subsurface runoff emerging at the ground surface.Five factors play an important role in maintaining a positive water balance and in replenishing groundwater via rainfall:effective rainfall as a water source,the high infiltration capacity of the sands enabling rainfall to rapidly become capillary water in the dunes,low evapotranspiration rates due to the sparse vegetation,the fact that the depth of the sand layer influenced by evaporation is shallow enough to maximize the deep infiltration of rainfall,and rapidly-moving gravity capillary water in the sandy dunes.These five factors together constitute a mechanism for groundwater recharge from rainfall,and explain the origin of the groundwater and lakes in the area.Our findings represent a significant advance in research on the hydrological cycle,including groundwater recharge conditions and recharge mechanisms,in this desert region.
