The precision modeling of dam break floods can lead to formulation of proper emergency action plan to minimize flood impacts within the economic lifetime of the assets.Application of GIS techniques in integration with...The precision modeling of dam break floods can lead to formulation of proper emergency action plan to minimize flood impacts within the economic lifetime of the assets.Application of GIS techniques in integration with hydrological modeling for mapping of the flood inundated areas can play a momentous role in further minimizing the risk and likely damages.In the present study,dam break analysis using DAMBRK model was performed under various likely scenarios.Probable Maximum Flood (PMF)calculated for a return period of 1000 years using deterministic approach was adopted for dam break analysis of the proposed dam under various combinations of breach dimensions.The available downstream river cross-sections data sets were used as input in the model to generate the downstream flood profile.Dam break flow depths generated by the DAMBRK model under various combinations of structural failure are subsequently plotted on Digital Elevation Model(DEM)of the downstream of dam site to map the likely affected area.The simulation results reveals that in one particular case the flood without dam may be more intense if a rainfall of significant intensity takes place.展开更多
Using bibliometric methods,this paper analyzes the total amount and keyword composition among 910 studies in the field of farmland abandonment published in the Web of Science database from 1992 to 2019.According to th...Using bibliometric methods,this paper analyzes the total amount and keyword composition among 910 studies in the field of farmland abandonment published in the Web of Science database from 1992 to 2019.According to the usage of keywords,existing studies are reviewed from the three aspects of monitoring and mapping,driving forces and influencing factors,and effects assessment and trade-off.The results show that:(1)At present,the extraction and mapping of abandoned farmland data mainly rely on household surveys and remote sensing technology,and combing NDVI time series with spatial information can provide abandoned farmland data with high precision.(2)The driving forces and influencing factors of cultivated land abandonment have been summarized in terms of extent,sources and attributes,respectively.Cultivated land marginalization is the fundamental driving force of cultivated land abandonment,labor migration is the direct driving force,and changes in socio-economic factors are the main driving forces.(3)The environmental effects of cultivated land abandonment are spatially heterogeneous,and temporal-spatial differences,the landscape environment,climate,cultivation and topographic features will all play decisive roles in shaping the ultimate environmental effects.Studies of trade-offs between the impacts of cultivated land abandonment mainly focus on ecosystem service function and value,while the role of spatial background is often ignored.Based on a systematic review of existing literature,this paper suggests that future efforts should carry out large-scale investigations on abandoned cultivated land at the national level,conduct multi-scale research on the driving forces of land abandonment,and conduct trade-off research on the effects of land abandonment based on national conditions.展开更多
文摘The precision modeling of dam break floods can lead to formulation of proper emergency action plan to minimize flood impacts within the economic lifetime of the assets.Application of GIS techniques in integration with hydrological modeling for mapping of the flood inundated areas can play a momentous role in further minimizing the risk and likely damages.In the present study,dam break analysis using DAMBRK model was performed under various likely scenarios.Probable Maximum Flood (PMF)calculated for a return period of 1000 years using deterministic approach was adopted for dam break analysis of the proposed dam under various combinations of breach dimensions.The available downstream river cross-sections data sets were used as input in the model to generate the downstream flood profile.Dam break flow depths generated by the DAMBRK model under various combinations of structural failure are subsequently plotted on Digital Elevation Model(DEM)of the downstream of dam site to map the likely affected area.The simulation results reveals that in one particular case the flood without dam may be more intense if a rainfall of significant intensity takes place.
基金The Research Project of Humanities and Social Sciences in Jiangxi Province(GL19111)The Key Project of Jiangxi Natural Science Foundation(20202ACB203004)The Science and Technology Project of Education Department in Jiangxi Province(GJJ200531)。
文摘Using bibliometric methods,this paper analyzes the total amount and keyword composition among 910 studies in the field of farmland abandonment published in the Web of Science database from 1992 to 2019.According to the usage of keywords,existing studies are reviewed from the three aspects of monitoring and mapping,driving forces and influencing factors,and effects assessment and trade-off.The results show that:(1)At present,the extraction and mapping of abandoned farmland data mainly rely on household surveys and remote sensing technology,and combing NDVI time series with spatial information can provide abandoned farmland data with high precision.(2)The driving forces and influencing factors of cultivated land abandonment have been summarized in terms of extent,sources and attributes,respectively.Cultivated land marginalization is the fundamental driving force of cultivated land abandonment,labor migration is the direct driving force,and changes in socio-economic factors are the main driving forces.(3)The environmental effects of cultivated land abandonment are spatially heterogeneous,and temporal-spatial differences,the landscape environment,climate,cultivation and topographic features will all play decisive roles in shaping the ultimate environmental effects.Studies of trade-offs between the impacts of cultivated land abandonment mainly focus on ecosystem service function and value,while the role of spatial background is often ignored.Based on a systematic review of existing literature,this paper suggests that future efforts should carry out large-scale investigations on abandoned cultivated land at the national level,conduct multi-scale research on the driving forces of land abandonment,and conduct trade-off research on the effects of land abandonment based on national conditions.
