Maiduguri metropolis Nigeria, lies on a relatively flat terrain of about 350 meters above sea level and is part of the undulating Borno Plain that slopes towards the Lake Chad. The rapid physical expansion of the metr...Maiduguri metropolis Nigeria, lies on a relatively flat terrain of about 350 meters above sea level and is part of the undulating Borno Plain that slopes towards the Lake Chad. The rapid physical expansion of the metropolis and the annual recurrent flash flooding and inundation problems within the city continues to impact devastating socioeconomic effects on the livelihood of residents sometimes leading to loss of lives and property. It is important therefore to understand the spatial pattern of floods and terrain characteristics in Maiduguri for planning purposes. The paper examined the spatial pattern of urban flash floods and inundations, and the terrain characteristics in Maiduguri metropolis. Digital Terrain Model (DTM) generated from the Shuttle Raddar Topography Mission was used to provide the basis for the terrain analysis to generate hydrological parameters such as elevation, flow accumulation and direction, drainage network and slope angle as well as classified elevation images and terrain wetness index to map out potential flood risk areas. The DTM identified potential areas liable to flash flood and inundation. The 3D Digital Terrain Model (DTM) of the area showed where potential floods or traps were located in the metropolis. The findings further revealed that Maiduguri was generally characterized by low lying locations with slope angles of less than 5 degrees covering an area of 144.4 km<sup>2</sup> out of 148 km<sup>2</sup> making it extremely difficult to drain. The processed flow accumulation of the study area showed a high flow accumulation pixel value of 19,972 that drained into outlet, suggesting that a large proportion of the study area was getting flooded during a rainstorm. Even though the calculated drainage density of 0.73 for the study area indicated a very good drainage system, this was also undermined by the flat terrain and urbanization. The study recommends for improved land use planning;raising awareness of the residents, provision of more drainages and continued vulnerability mapping improved the functionality of bodies responsible for flood management among others for sustainable flood management in the study area.展开更多
The Philippines is among the most disaster-prone nations.Its islands are frequently hit by floods,typhoons,landslides,earthquakes,volcanic eruptions,and droughts due to their location along major tectonic plates and i...The Philippines is among the most disaster-prone nations.Its islands are frequently hit by floods,typhoons,landslides,earthquakes,volcanic eruptions,and droughts due to their location along major tectonic plates and in a typhoon belt.The country is blessed with oceans,rivers,lakes,and streams,but weather events can release massive amounts of water,causing flooding.This study investigates Philippine flash floods,their sources,effects,and solutions.It focuses on major floods,including those caused by both typhoons and monsoons,as well as susceptible locations and ASEAN prevention methods.Employing a descriptive-evaluative research design,this study aligns with Ary's notion that descriptive research seeks to capture the current state of affairs.It entails data mining from reliable,pertinent sources to inform the study's outcomes.Analysis reveals that recurrent flash floods pose a considerable risk across all Philippine regions,with Region III standing out as particularly susceptible.The catastrophic flooding induced by Super Typhoon Yolanda marked the most severe flooding event in the Philippines between 2010 and 2020.However,monsoon-induced floods also significantly contributed to annual flooding,particularly in highly urbanized and coastal areas.Attention and resources should be prioritized for Northern Luzon,notably Regions I,III,IV-A,IV-B,and CAR,which exhibit a high frequency of flash flood recurrences.Implementing actionable flood risk information and robust flood warning systems,reinforcing drainage infrastructure,allocating budgets for flood prevention initiatives,promoting tree planting,and adopting Cambodia's HYDRA Floods approach represent viable flood prevention measures tailored for the Philippines'flood-prone regions.展开更多
文摘Maiduguri metropolis Nigeria, lies on a relatively flat terrain of about 350 meters above sea level and is part of the undulating Borno Plain that slopes towards the Lake Chad. The rapid physical expansion of the metropolis and the annual recurrent flash flooding and inundation problems within the city continues to impact devastating socioeconomic effects on the livelihood of residents sometimes leading to loss of lives and property. It is important therefore to understand the spatial pattern of floods and terrain characteristics in Maiduguri for planning purposes. The paper examined the spatial pattern of urban flash floods and inundations, and the terrain characteristics in Maiduguri metropolis. Digital Terrain Model (DTM) generated from the Shuttle Raddar Topography Mission was used to provide the basis for the terrain analysis to generate hydrological parameters such as elevation, flow accumulation and direction, drainage network and slope angle as well as classified elevation images and terrain wetness index to map out potential flood risk areas. The DTM identified potential areas liable to flash flood and inundation. The 3D Digital Terrain Model (DTM) of the area showed where potential floods or traps were located in the metropolis. The findings further revealed that Maiduguri was generally characterized by low lying locations with slope angles of less than 5 degrees covering an area of 144.4 km<sup>2</sup> out of 148 km<sup>2</sup> making it extremely difficult to drain. The processed flow accumulation of the study area showed a high flow accumulation pixel value of 19,972 that drained into outlet, suggesting that a large proportion of the study area was getting flooded during a rainstorm. Even though the calculated drainage density of 0.73 for the study area indicated a very good drainage system, this was also undermined by the flat terrain and urbanization. The study recommends for improved land use planning;raising awareness of the residents, provision of more drainages and continued vulnerability mapping improved the functionality of bodies responsible for flood management among others for sustainable flood management in the study area.
文摘The Philippines is among the most disaster-prone nations.Its islands are frequently hit by floods,typhoons,landslides,earthquakes,volcanic eruptions,and droughts due to their location along major tectonic plates and in a typhoon belt.The country is blessed with oceans,rivers,lakes,and streams,but weather events can release massive amounts of water,causing flooding.This study investigates Philippine flash floods,their sources,effects,and solutions.It focuses on major floods,including those caused by both typhoons and monsoons,as well as susceptible locations and ASEAN prevention methods.Employing a descriptive-evaluative research design,this study aligns with Ary's notion that descriptive research seeks to capture the current state of affairs.It entails data mining from reliable,pertinent sources to inform the study's outcomes.Analysis reveals that recurrent flash floods pose a considerable risk across all Philippine regions,with Region III standing out as particularly susceptible.The catastrophic flooding induced by Super Typhoon Yolanda marked the most severe flooding event in the Philippines between 2010 and 2020.However,monsoon-induced floods also significantly contributed to annual flooding,particularly in highly urbanized and coastal areas.Attention and resources should be prioritized for Northern Luzon,notably Regions I,III,IV-A,IV-B,and CAR,which exhibit a high frequency of flash flood recurrences.Implementing actionable flood risk information and robust flood warning systems,reinforcing drainage infrastructure,allocating budgets for flood prevention initiatives,promoting tree planting,and adopting Cambodia's HYDRA Floods approach represent viable flood prevention measures tailored for the Philippines'flood-prone regions.
