Flood land, with abundant light, heat, and water resource, is an important potential land resource to resolve the situation of the limited arable land in mountain areas in Xiaojiang Valley, Dongchuan, Yunnan. It will ...Flood land, with abundant light, heat, and water resource, is an important potential land resource to resolve the situation of the limited arable land in mountain areas in Xiaojiang Valley, Dongchuan, Yunnan. It will have a great significance on the development of local characteristic agriculture and the settlement of poor moun- tain immigrants that how to develop and protect the flood land in a scientific, effec- tive and sustainable way. In this paper, flood land of Xiaojiang Valley is divided into three zones （higher zone is 1 600-1 300 m, medium zone is 1 300-1 000 m, low- er zone is 1 000-700 m） according to different elevations. Through field survey, in situ measurement, sampling analysis and ＂3S＂ technology, the area and soil nutri- ent characteristics of flood land at different altitudes are tested and analyzed sys- tematically. And also according to the climatic characteristics in different elevations of flood land, the research analyzed and investigated the growing conditions of flood land in different elevations in Xiaojiang Valley, and then discussed how to develop and cultivate reasonably and effectively in flood land. All the work is intended to provide beneficial reference for the development and cultivation of flood land in mountain areas.展开更多
In the summer of 1998, a rarely severe flooding disaster occurred in the whole basin of the Changjiang(Yangtze) River, which caused enormous losses. By 22nd of August, 29 provinces, autonomous regions and municipaliti...In the summer of 1998, a rarely severe flooding disaster occurred in the whole basin of the Changjiang(Yangtze) River, which caused enormous losses. By 22nd of August, 29 provinces, autonomous regions and municipalitieswere involved, 21. 2 million ha of land were inundated, 223 million people were affected, 3004 people were killed and4. 97 million buildings were collapsed. The estimated direct loss of the country accounted to 166. 6 billion yuan (RMB).The main reason of the disaster is the unusual climate but the unreasonable land utilization the aggravated the disaster.This paper consists of two parts. One part analysed the unreasonable land utilization, including the neglect of forest landprotection, which caused the forest land area to decrease by 440 thousand ha in the whole country every year, the enclosing of lakes for cultivation, which decreased the area of lakes located along the banks of the Changjiang River from 17 200km2 at the beginning of the founding of the People’s Republic of China to 6531 km2 in 1983, the changing of functions oflakes, which reduced the volume of storage exceedingly, for example, only 5 spots of lakes were used for storing water inWuhan City, and the slow progress of the construction of flood diversion and storage area, which would cause huge lossesonce flood was diverted. The other part explored the strategy of land utilization on the supplying of land for flood controlprojects, such as embankment, drainage installation, flood diversion and storage area, and on tapping the potentialsthrough narrowing and amalgamgting the range of rural residential quarters and small towns, reclaiming reserved resources, transforming middle and low productive fields, attaching importance to land arrangement and recultivation, and adjusting contracted fields partially, to ensure the sustainable and stable growth of the region.展开更多
Floodwaters from the Assiniboine River are typically diverted to Lake Manitoba and then Lake St. Martin to save the City of Winnipeg and Portage la Prairie from flooding. The four Indigenous communities living Lake St...Floodwaters from the Assiniboine River are typically diverted to Lake Manitoba and then Lake St. Martin to save the City of Winnipeg and Portage la Prairie from flooding. The four Indigenous communities living Lake St. Martin basin experienced many negative impacts, including long-term displacement after the 2011 flood. Data analysis of historical water levels of Lake Manitoba and Lake St. Martin were conducted to understand the impact of control structures and water levels. Satellite imagery allowed geographic information system (GIS) raster analysis of the shoreline change of Lake St. Martin before and after the 2011 super flood. From 1986 to 2010, the Lake St. Martin area increased slightly by approximately 0.63% but in 2011 the lake area increased by 13%. 11,000 acres were lost mainly around Lake St. Martin First Nation (LSMFN) reserve and the Little Saskatchewan First Nation, as a result and many houses and other buildings (churches, band offices, etc.) flooded in these communities. The shoreline change analysis showed that, in particular, the west and north shoreline of Lake St. Martin lost its beaches and lakefront properties, to become swampland after the 2011 flood. Thousands of Indigenous people were displaced for eight years, as the community could only start to rebuild its infrastructure and houses on higher ground after a government settlement was reached.展开更多
Flood of Changjiang River (the Yangtze) in 1998 is so serious that it arouses our keen concern about its causes. In this paper, the authors bring out a brief history of the flood disaster happened to the Changjiang R...Flood of Changjiang River (the Yangtze) in 1998 is so serious that it arouses our keen concern about its causes. In this paper, the authors bring out a brief history of the flood disaster happened to the Changjiang River Valley in the last six centuries and analyze the causes for the frequent flood disaters based on the land use and land cover change in the upper and middle-lower reaches of the Changjiang River.展开更多
In order to understand the effect of the land use/cover change on the hydrologic regime of the Madarsu Basin in Golestan province of Iran, we selected the two floods of June 1964 and June 2003 with equal amount of rai...In order to understand the effect of the land use/cover change on the hydrologic regime of the Madarsu Basin in Golestan province of Iran, we selected the two floods of June 1964 and June 2003 with equal amount of rainfall but different rate of runoff. For these floods the closest time images of MODIS were selected. On these images we analyzed the land use/cover types and calculated their area and change rate between two floods. We also calculated the Curve Number (CN) for each land use/cover type according to the US Soil Conservation System (SCS) model. The results showed that: the intensity of the peak floods has increased from 1960 to 2002, and the natural lands of forests, rangelands, and bare lands have been decreased from 1960 to 2002. While the agricultural lands showed increase during the same period. The CN value has also increased during the study period causing the decrease of moisture retention capacity of the soil. As a result, despite the equal rainfall, the discharge rate of 2003 flood was about 10 times larger than that of the 1964 flood, which is the direct effect of the land use/cover change from the stable forests and rangelands to the unstable agricultural lands on the both soil moisture retention capacity and run off rate.展开更多
Flood is a common feature in rapidly urbanizing Dhaka city and its surrounding areas. In this research, evaluation of flood risk of Greater Dhaka in Bangladesh has been developed by using an integrated approach of GIS...Flood is a common feature in rapidly urbanizing Dhaka city and its surrounding areas. In this research, evaluation of flood risk of Greater Dhaka in Bangladesh has been developed by using an integrated approach of GIS and remote sensing. The objective of the study is to measure the flooding risk based on the satellite data and geomorphological land classification map under the land use/land cover change from 1995 to 2015 related with the urbanization of Dhaka city. Comparing with each landform, land cover unit and historical rainfall data the flooding return period has been calculated. Terrace, natural levee and back swamp has been divided into three sub categories. Especially the built-up zone which is closer to the river channel, former river course and the back swamps are mostly vulnerable to flood inundation. This study revealed that, 70% of Greater Dhaka district within moderate to very high hazard zone, especially surrounding city like Manikganj Sadar Upazila areas. It is expected that, this study could contribute to effective flood forecasting, relief and emergency management for future flood event.展开更多
The world population has been increasing while, similarly, both the number of environmental disasters and the loss resulting from those have been on the rise. It is also expected that the trend will continue. Especial...The world population has been increasing while, similarly, both the number of environmental disasters and the loss resulting from those have been on the rise. It is also expected that the trend will continue. Especially, what is noticeable is that more and more people and property concentrate on cities. In fact, urbanization is a major global trend simply because most people want to get their jobs, raise and educate their children, and enjoy riches of diverse cultures, recreation activities, and entertainment, which cities can provide to them. Urbanization always involves transforming the natural environment into a man-made environment, contributing to changes in land use and land cover patterns as well as in landscape and hydrology in the built-up areas. These changes, in turn, negatively influence the natural environment because those changes almost always tend to result in the disruption of its fragile ecosystems in balance. In addition, the changes mean the land used, for example, for a natural ecosystem may be converted into an impervious land, which can increase human vulnerability to floods, causing human and property losses. There has been some research done to investigate the relationship between land use/land cover change and environmental hazards. However, little research has been conducted to test direct effects of land cover change on environmental disasters such as floods, hurricanes, and hazardous material releases by using GIS and remote sensing technologies. Therefore, this research aimed to analyze the effect of land cover change on floods. More specifically, the research tested whether land cover change is related to flood disasters in Texas from 1993 to 2012. One of the main findings of this research is that both decrease in forest areas and increase in urban built-up areas contributed to the property damage resulting from flood events.展开更多
Many natural disasters have recently occurred in Laos. Among them, flooding has been the greatest problem. Land use change (deforestation and urbanization) and climate change have played significant roles, and it is i...Many natural disasters have recently occurred in Laos. Among them, flooding has been the greatest problem. Land use change (deforestation and urbanization) and climate change have played significant roles, and it is important to understand the impacts of these changes on flooding. We have developed an integrated hazard map based on a combination of four hazard maps of flooding, land use change and climate change to assess hazard areas at the national scale. The hazard map was developed using the analytical hierarchy process (AHP) and a hazard index. Finally, we divided the map into four hazard area categories, which include low, medium, intermediate and high. Based on this analysis, the integrated hazard map of Laos indicates that low hazard areas cover 87.44% of the total area, medium hazard areas cover 8.12%, and intermediate and high hazard areas respectively cover 2.42% and 2% of the land area. We compared the results with historical events to confirm that the proposed methodology is valid.展开更多
Floods are one of the major hazards worldwide. They are the source of huge risks in rural and urban areas, resulting in severe impacts on the civil society, industry and the economy. The Elbe River has suffered from m...Floods are one of the major hazards worldwide. They are the source of huge risks in rural and urban areas, resulting in severe impacts on the civil society, industry and the economy. The Elbe River has suffered from many severe floods during recent decades. In this study, the zones flooded during 2011 were analyzed using TerraSAR-X images and a digital elevation model for the area in order to identify possible ways to mitigate flood hazards in the future, regarding sustainable land-use. Two study areas are investigated, around the Walmsburg oxbow and the Wehningen oxbow. These are located between Elbe-Kilometer (505-520) and (533-543), respectively, within the Lower Saxonian Elbe River Biosphere Reserve. Those areas are characterized by several types of land use, with agricultural land use being predominant. The study investigated the possibility of using a Decision-Tree object-based classifier for determining the major land uses and the extent of the inundation areas. The inundation areas identify for 2011 submerged some agricultural fields that must be added to existing flood risk maps, and future cultivation activities there prevented to avoid the possible economic losses. Furthermore, part of the residential area is located within the high flood zone, and must be included in risk maps to avoid the possible human and economic losses, to achieve sustainable land use for the areas studied.展开更多
基金Supported by National Technology R&D Program(0BAC06B02)~~
文摘Flood land, with abundant light, heat, and water resource, is an important potential land resource to resolve the situation of the limited arable land in mountain areas in Xiaojiang Valley, Dongchuan, Yunnan. It will have a great significance on the development of local characteristic agriculture and the settlement of poor moun- tain immigrants that how to develop and protect the flood land in a scientific, effec- tive and sustainable way. In this paper, flood land of Xiaojiang Valley is divided into three zones （higher zone is 1 600-1 300 m, medium zone is 1 300-1 000 m, low- er zone is 1 000-700 m） according to different elevations. Through field survey, in situ measurement, sampling analysis and ＂3S＂ technology, the area and soil nutri- ent characteristics of flood land at different altitudes are tested and analyzed sys- tematically. And also according to the climatic characteristics in different elevations of flood land, the research analyzed and investigated the growing conditions of flood land in different elevations in Xiaojiang Valley, and then discussed how to develop and cultivate reasonably and effectively in flood land. All the work is intended to provide beneficial reference for the development and cultivation of flood land in mountain areas.
文摘In the summer of 1998, a rarely severe flooding disaster occurred in the whole basin of the Changjiang(Yangtze) River, which caused enormous losses. By 22nd of August, 29 provinces, autonomous regions and municipalitieswere involved, 21. 2 million ha of land were inundated, 223 million people were affected, 3004 people were killed and4. 97 million buildings were collapsed. The estimated direct loss of the country accounted to 166. 6 billion yuan (RMB).The main reason of the disaster is the unusual climate but the unreasonable land utilization the aggravated the disaster.This paper consists of two parts. One part analysed the unreasonable land utilization, including the neglect of forest landprotection, which caused the forest land area to decrease by 440 thousand ha in the whole country every year, the enclosing of lakes for cultivation, which decreased the area of lakes located along the banks of the Changjiang River from 17 200km2 at the beginning of the founding of the People’s Republic of China to 6531 km2 in 1983, the changing of functions oflakes, which reduced the volume of storage exceedingly, for example, only 5 spots of lakes were used for storing water inWuhan City, and the slow progress of the construction of flood diversion and storage area, which would cause huge lossesonce flood was diverted. The other part explored the strategy of land utilization on the supplying of land for flood controlprojects, such as embankment, drainage installation, flood diversion and storage area, and on tapping the potentialsthrough narrowing and amalgamgting the range of rural residential quarters and small towns, reclaiming reserved resources, transforming middle and low productive fields, attaching importance to land arrangement and recultivation, and adjusting contracted fields partially, to ensure the sustainable and stable growth of the region.
文摘Floodwaters from the Assiniboine River are typically diverted to Lake Manitoba and then Lake St. Martin to save the City of Winnipeg and Portage la Prairie from flooding. The four Indigenous communities living Lake St. Martin basin experienced many negative impacts, including long-term displacement after the 2011 flood. Data analysis of historical water levels of Lake Manitoba and Lake St. Martin were conducted to understand the impact of control structures and water levels. Satellite imagery allowed geographic information system (GIS) raster analysis of the shoreline change of Lake St. Martin before and after the 2011 super flood. From 1986 to 2010, the Lake St. Martin area increased slightly by approximately 0.63% but in 2011 the lake area increased by 13%. 11,000 acres were lost mainly around Lake St. Martin First Nation (LSMFN) reserve and the Little Saskatchewan First Nation, as a result and many houses and other buildings (churches, band offices, etc.) flooded in these communities. The shoreline change analysis showed that, in particular, the west and north shoreline of Lake St. Martin lost its beaches and lakefront properties, to become swampland after the 2011 flood. Thousands of Indigenous people were displaced for eight years, as the community could only start to rebuild its infrastructure and houses on higher ground after a government settlement was reached.
基金Under the auspices of National Natural Science Foundation of China !49731040
文摘Flood of Changjiang River (the Yangtze) in 1998 is so serious that it arouses our keen concern about its causes. In this paper, the authors bring out a brief history of the flood disaster happened to the Changjiang River Valley in the last six centuries and analyze the causes for the frequent flood disaters based on the land use and land cover change in the upper and middle-lower reaches of the Changjiang River.
文摘In order to understand the effect of the land use/cover change on the hydrologic regime of the Madarsu Basin in Golestan province of Iran, we selected the two floods of June 1964 and June 2003 with equal amount of rainfall but different rate of runoff. For these floods the closest time images of MODIS were selected. On these images we analyzed the land use/cover types and calculated their area and change rate between two floods. We also calculated the Curve Number (CN) for each land use/cover type according to the US Soil Conservation System (SCS) model. The results showed that: the intensity of the peak floods has increased from 1960 to 2002, and the natural lands of forests, rangelands, and bare lands have been decreased from 1960 to 2002. While the agricultural lands showed increase during the same period. The CN value has also increased during the study period causing the decrease of moisture retention capacity of the soil. As a result, despite the equal rainfall, the discharge rate of 2003 flood was about 10 times larger than that of the 1964 flood, which is the direct effect of the land use/cover change from the stable forests and rangelands to the unstable agricultural lands on the both soil moisture retention capacity and run off rate.
文摘Flood is a common feature in rapidly urbanizing Dhaka city and its surrounding areas. In this research, evaluation of flood risk of Greater Dhaka in Bangladesh has been developed by using an integrated approach of GIS and remote sensing. The objective of the study is to measure the flooding risk based on the satellite data and geomorphological land classification map under the land use/land cover change from 1995 to 2015 related with the urbanization of Dhaka city. Comparing with each landform, land cover unit and historical rainfall data the flooding return period has been calculated. Terrace, natural levee and back swamp has been divided into three sub categories. Especially the built-up zone which is closer to the river channel, former river course and the back swamps are mostly vulnerable to flood inundation. This study revealed that, 70% of Greater Dhaka district within moderate to very high hazard zone, especially surrounding city like Manikganj Sadar Upazila areas. It is expected that, this study could contribute to effective flood forecasting, relief and emergency management for future flood event.
文摘The world population has been increasing while, similarly, both the number of environmental disasters and the loss resulting from those have been on the rise. It is also expected that the trend will continue. Especially, what is noticeable is that more and more people and property concentrate on cities. In fact, urbanization is a major global trend simply because most people want to get their jobs, raise and educate their children, and enjoy riches of diverse cultures, recreation activities, and entertainment, which cities can provide to them. Urbanization always involves transforming the natural environment into a man-made environment, contributing to changes in land use and land cover patterns as well as in landscape and hydrology in the built-up areas. These changes, in turn, negatively influence the natural environment because those changes almost always tend to result in the disruption of its fragile ecosystems in balance. In addition, the changes mean the land used, for example, for a natural ecosystem may be converted into an impervious land, which can increase human vulnerability to floods, causing human and property losses. There has been some research done to investigate the relationship between land use/land cover change and environmental hazards. However, little research has been conducted to test direct effects of land cover change on environmental disasters such as floods, hurricanes, and hazardous material releases by using GIS and remote sensing technologies. Therefore, this research aimed to analyze the effect of land cover change on floods. More specifically, the research tested whether land cover change is related to flood disasters in Texas from 1993 to 2012. One of the main findings of this research is that both decrease in forest areas and increase in urban built-up areas contributed to the property damage resulting from flood events.
文摘Many natural disasters have recently occurred in Laos. Among them, flooding has been the greatest problem. Land use change (deforestation and urbanization) and climate change have played significant roles, and it is important to understand the impacts of these changes on flooding. We have developed an integrated hazard map based on a combination of four hazard maps of flooding, land use change and climate change to assess hazard areas at the national scale. The hazard map was developed using the analytical hierarchy process (AHP) and a hazard index. Finally, we divided the map into four hazard area categories, which include low, medium, intermediate and high. Based on this analysis, the integrated hazard map of Laos indicates that low hazard areas cover 87.44% of the total area, medium hazard areas cover 8.12%, and intermediate and high hazard areas respectively cover 2.42% and 2% of the land area. We compared the results with historical events to confirm that the proposed methodology is valid.
文摘Floods are one of the major hazards worldwide. They are the source of huge risks in rural and urban areas, resulting in severe impacts on the civil society, industry and the economy. The Elbe River has suffered from many severe floods during recent decades. In this study, the zones flooded during 2011 were analyzed using TerraSAR-X images and a digital elevation model for the area in order to identify possible ways to mitigate flood hazards in the future, regarding sustainable land-use. Two study areas are investigated, around the Walmsburg oxbow and the Wehningen oxbow. These are located between Elbe-Kilometer (505-520) and (533-543), respectively, within the Lower Saxonian Elbe River Biosphere Reserve. Those areas are characterized by several types of land use, with agricultural land use being predominant. The study investigated the possibility of using a Decision-Tree object-based classifier for determining the major land uses and the extent of the inundation areas. The inundation areas identify for 2011 submerged some agricultural fields that must be added to existing flood risk maps, and future cultivation activities there prevented to avoid the possible economic losses. Furthermore, part of the residential area is located within the high flood zone, and must be included in risk maps to avoid the possible human and economic losses, to achieve sustainable land use for the areas studied.
