scholarly journals Modeling the Propagation of Flood Waves at the Mouth of the Comoé River in Grand-Bassam (South East of Côte d’Ivoire)

2021 ◽  
pp. 33-42
Author(s):  
Kouakou Hervé Kouassi ◽  
Zilé Alex Kouadio ◽  
Yao Alexis N’go ◽  
Berenger Koffi ◽  
Gla Blaise Ouédé
Keyword(s):  
At Risk ◽  
Cote D'ivoire ◽  
Satellite Images ◽  
High Water ◽  
Climatic Data ◽  
Return Periods ◽  
Maximum Frequency ◽  
Topographic Data ◽  
Flooded Areas ◽  
Flood Waves

This study was carried out in order to determine the areas at risk of flooding during high water periods at the mouth of the Comoé River in Grand-Bassam. The database is essentially made up of hydro-climatic data, satellite images and topographic data. According to the various criteria, the Weibull law was selected to estimate the maximum frequency flows. According to this law, the flows at the return periods of 2, 10, 50 and 100 years are respectively 634, 733, 781 and 797 m3 / s. The modeling results showed that the areas exposed to the risk of flooding are located near the Ouladine lagoon and the Ebrié lagoon at the mouth of the Comoé river. The extent of the floodplains varies with flooded areas of the order of 85.63 km²; 89.42 km²; 101.67 km²; 107.10 km² for the return periods of 2; 10; 50 and 100 years old.

scholarly journals The 2007 flood in the Sahel: causes, characteristics and its presentation in the media and FEWS NET

2012 ◽  
Vol 12 (2) ◽  
pp. 313-325 ◽  
Author(s):  
C. Samimi ◽  
A. H. Fink ◽  
H. Paeth
Keyword(s):  
Rainy Season ◽  
Satellite Images ◽  
Local Population ◽  
Return Periods ◽  
Volta Basin ◽  
The Media ◽  
Ground Truthing ◽  
Upper Volta ◽  
Flooded Areas ◽  
Interpretation Of Satellite Images

Abstract. During the rainy season in 2007, reports about exceptional rains and floodings in the Sahel were published in the media, especially in August and September. Institutions and organizations like the World Food Programme (WFP) and FEWS NET put the events on the agenda and released alerts and requested help. The partly controversial picture was that most of the Sahel faced a crisis caused by widespread floodings. Our study shows that the rainy season in 2007 was exceptional with regard to rainfall amount and return periods. In many areas the event had a return period between 1 and 50 yr with high spatial heterogeneity, with the exception of the Upper Volta basin, which yielded return periods of up to 1200 yr. Despite the strong rainfall, the interpretation of satellite images show that the floods were mainly confined to lakes and river beds. However, the study also proves the difficulties in assessing the meteorological processes and the demarcation of flooded areas in satellite images without ground truthing. These facts and the somewhat vague and controversial reports in the media and FEWS NET demonstrate that it is crucial to thoroughly analyze such events at a regional and local scale involving the local population.

scholarly journals SLOPE FAILURE RISK ASSESSMENT MODELING USING TOPOGRAPHIC DATA AND NUMERICAL CALCULATION OF SOIL CONSERVATION BY TREE ROOT SYSTEMS

2019 ◽  
Vol IV-2/W5 ◽  
pp. 217-222
Author(s):  
T. Mori ◽  
T. Sugiyama ◽  
I. Hosooka ◽  
M. Nakata ◽  
K. Okano ◽  
...  
Keyword(s):  
Risk Assessment ◽  
At Risk ◽  
Slope Failure ◽  
Forest Type ◽  
Heavy Rain ◽  
Root Systems ◽  
Topographic Data ◽  
Relative Risk Assessment ◽  
External Forces ◽  
Heavy Rains

<p><strong>Abstract.</strong> In Japan, the frequency of sudden heavy rain events has recently increased, causing slope failures that in turn increase rates of damage to transit infrastructure such as railways and roads. To reduce this damage, there is a need to identify locations near railroad tracks that are at risk of slope failure. Thus, an assessment that predicts whether or not damage will occur due to external forces such as heavy rains is required, rather than a simple relative risk assessment based on identifying locations similar to those damaged in previous events. In this study, we developed a method for time series stability assessment of slopes during heavy rains using digital topographic data. This method uses topographic data to estimate topsoil thickness, which contributes to stability, and soil strength, which is affected by the root systems of vegetation on slopes. Using differences in these parameters between tree species and forest type, we were able to calculate slope stability and simulate slope failure during rainfall. The simulations allowed us to evaluate locations along routes where previous failures occurred, and to identify at-risk locations that have not yet experienced slope failure. This approach will improve forest management based on risk assessments for intensifying heavy rains.</p>

Numerical Simulation of Engineering Wave for Zhongzui Bay

2007 ◽  
Author(s):  
Xiejun Shu ◽  
Senhui Jiang ◽  
Ruijie Li
Keyword(s):  
Numerical Simulation ◽  
Water Level ◽  
Simulation Method ◽  
High Water ◽  
Wave Transformation ◽  
Return Periods ◽  
Engineering Construction ◽  
Wave Refraction ◽  
High Water Level ◽  
Mild Slope Equation

For providing a better shelter condition, it is necessary to build a breakwater in Zhongzui Bay. In order to know whether mooring area meets the requirement after engineering construction and compare the mooring area between solid breakwater and permeable breakwater, a numerical simulation method is used in the sheltering harbor of Zhongzui Bay. The used Mild-slope equation which describes wave refraction, diffraction and reflection, considers the steep slope bottom and effect of energy dissipation. It has been validated to fit for simulating wave transformation in the coastal zone. Under extreme high water level and design high water level, wave fields in the calculation area of three wave types in three different return periods are simulated by using this method respectively. In addition, wave height in front of breakwater can be provided. Then the wave parameters and the mooring area of two occasions, with and without breakwater, are gained in calculation area. Based on these results, some conclusions are presented in the end.

scholarly journals Socio -Territorial Transformations of the Northeast Region of Uruguay (2000-2018)

2020 ◽  
Vol 1 (31) ◽  
pp. 241-267
Author(s):  
Rodrigo Pereira ◽  
Marcel Borras ◽  
Gabril Scaraffuni ◽  
Janete Cancelier
Keyword(s):  
At Risk ◽  
Land Use ◽  
Satellite Images ◽  
Social Dynamics ◽  
Statistical Data ◽  
The Other ◽  
Territorial Expansion ◽  
Northeast Region ◽  
Other Hand ◽  
Agricultural Census

This article aims to understand how socio-territorial transformations have been manifesting in the northeast region of Uruguay between 2000 and 2018. In this period, the territorial expansion of agribusiness through soy monoculture and forestry intensifies, which causes important changes in the productive, social, and landscape base. The objective is, on one hand, to describe quantitatively and in terms of changes in land use, the recent transformations in the agrarian territories of the region and, on the other hand, to understand the impacts of these processes on some social dynamics, especially in the migration of family producers and their families from the agrarian space to the urban one. The methodology included a bibliographic and documentary review, the analysis of statistical data from the General Agricultural Census, and the analysis of land use through satellite images. The results show that monocultures linked to agribusiness have modified the agrarian structure and the use of the territory resulting in increasing pressure on the price of land, which puts the permanence of family producers at risk

scholarly journals CONTAR, MEDIR E IR ALÉM: o sentido dos dados em estudos geográficos do clima

2021 ◽  
Vol 7 (20) ◽  
pp. 202120
Author(s):  
Lucas Barbosa e Souza
Keyword(s):  
At Risk ◽  
Political Ecology ◽  
Knowledge Construction ◽  
Physical Geography ◽  
Climatic Data ◽  
Climate Data ◽  
Critical Approach ◽  
Philosophical Concept ◽  
Field Works ◽  
Climate Studies

COUNTING, MEASURING AND GOING BEYOND: the meaning of data in geographic climate studiesCONTAR, MEDIR E IR MÁS ALLÁ: el significado de los datos en los estudios geográficos del climaRESUMOEste artigo busca discutir o sentido dos dados utilizados nos estudos geográficos do clima, considerando os limites da quantificação, o conceito filosófico de intencionalidade, as diferenças entre construção de conhecimento e construção de sentido na ciência, além das possibilidades de exame do tema a partir da Geografia do Clima, da Ecologia Política e da Geografia Física Crítica. O texto foi proposto devido às facilidades atuais para se acessar dados climáticos ou mensurá-los diretamente em trabalhos de campo, mas sob risco de uma abordagem acrítica de suas conexões com fatos sociais e políticos, por exemplo. Assim, o objetivo principal é contribuir para reforçar o significado do clima no âmbito da Geografia e os possíveis ganhos com o diálogo entre a Climatologia e outras perspectivas analíticas, especialmente nas ciências humanas.Palavras-chave: Dados Climáticos; Abordagem Crítica em Climatologia; Conhecimento e Sentido em Climatologia; Interdisciplinaridade.ABSTRACTThis paper seeks to discuss the sense of data used in geographic climate studies, considering the limits of quantification, the philosophical concept of intentionality, the differences between knowledge construction and sense construction in science besides the possibilities for examining the topic from the Geography of Climate, Political Ecology and Critical Physical Geography. The text was proposed due to the current facility to access climate data or mesure them directly in field works, but at risk of an uncritical approach of its connections with social and political facts, for example. Thus, the main purpose is contribute to reinforce the meaning of climate in the domain of Geography and the possible gains with the dialogue among Climatology and others analitical perpectives, especially in the human sciences.Keywords: Climatic Data; Critical Approach to Climatology; Knowledge and Meaning in Climatology; Interdisciplinarity.RESUMENEste artículo busca discutir el sentido de los datos utilizados en los estudios geográficos del clima, considerando los límites de la cuantificación, el concepto filosófico de intencionalidad, las diferencias entre la construcción del conocimiento y la construcción de los sentidos en la ciencia, además de las posibilidades de examinar el tema desde la perspectiva de la Geografía del Clima, Ecología Política y Geografía Física Crítica. El texto fue propuesto teniendo en cuenta la facilidad actual para acceder a los datos climáticos o medirlos directamente en el trabajo de campo, pero a riesgo de un enfoque acrítico de sus conexiones con hechos sociales y políticos, por ejemplo. Por lo tanto, el objetivo principal es contribuir a reforzar el significado del clima en el ámbito de la Geografía y las posibles ganancias con el diálogo entre la Climatología y otras perspectivas analíticas, especialmente en las ciencias humanas.Palabras clave: Datos Climáticos; Enfoque Crítico de la Climatología; Conocimiento y Significado en Climatología; Interdisciplinariedad.

scholarly journals Characterization of the 2014 Indus River Flood Using Hydraulic Simulations and Satellite Images

2021 ◽  
Vol 13 (11) ◽  
pp. 2053
Author(s):  
Aqil Tariq ◽  
Hong Shu ◽  
Alban Kuriqi ◽  
Saima Siddiqui ◽  
Alexandre S. Gagnon ◽  
...  
Keyword(s):  
Frequency Analysis ◽  
Satellite Images ◽  
Flood Frequency ◽  
Spatial Extent ◽  
Flood Frequency Analysis ◽  
Army Corps ◽  
Landsat 8 ◽  
Return Periods ◽  
Indus River ◽  
Study Region

Rivers play an essential role to humans and ecosystems, but they also burst their banks during floods, often causing extensive damage to crop, property, and loss of lives. This paper characterizes the 2014 flood of the Indus River in Pakistan using the US Army Corps of Engineers Hydrologic Engineering Centre River Analysis System (HEC-RAS) model, integrated into a geographic information system (GIS) and satellite images from Landsat-8. The model is used to estimate the spatial extent of the flood and assess the damage that it caused by examining changes to the different land-use/land-cover (LULC) types of the river basin. Extreme flows for different return periods were estimated using a flood frequency analysis using a log-Pearson III distribution, which the Kolmogorov–Smirnov (KS) test identified as the best distribution to characterize the flow regime of the Indus River at Taunsa Barrage. The output of the flood frequency analysis was then incorporated into the HEC-RAS model to determine the spatial extent of the 2014 flood, with the accuracy of this modelling approach assessed using images from the Moderate Resolution Imaging Spectroradiometer (MODIS). The results show that a supervised classification of the Landsat images was able to identify the LULC types of the study region with a high degree of accuracy, and that the most affected LULC was crop/agricultural land, of which 50% was affected by the 2014 flood. Finally, the hydraulic simulation of extent of the 2014 flood was found to visually compare very well with the MODIS image, and the surface area of floods of different return periods was calculated. This paper provides further evidence of the benefit of using a hydrological model and satellite images for flood mapping and for flood damage assessment to inform the development of risk mitigation strategies.

scholarly journals A Framework for Classifying and Assessing Sea Level Rise Risk

2020 ◽  
Author(s):  
Mathew Hauer ◽  
Dean Hardy ◽  
Scott Kulp ◽  
Valerie Mueller ◽  
David Wrathall ◽  
...  
Keyword(s):  
At Risk ◽  
Sea Level Rise ◽  
Sea Level ◽  
High Tide ◽  
High Water ◽  
At Risk Populations ◽  
Adaptation Policies ◽  
New Research ◽  
High Tide Line ◽  
Impacts Of Climate Change

Population risk assessments of sea level rise are key to understanding the impacts of climate change on coastal communities and necessary for adaptation planning. Future sea level rise exposes coastal populations to a spectrum of risk, but assessments often define exposure narrowly, such as areas experiencing permanent inundation only. We reviewed the most common sea level rise exposure assessment methods and identified three widely used spatial definitions of physical exposure risk: mean higher high water, the 100-year floodplain, and the low-elevation coastal zone. Taken individually, each treat risk to sea level rise as binary (affected or not affected), resulting in narrow definitions, homogenizing risk and exposure across space and time. We present a framework that integrates and smooths these classifications under a single continuous metric. To do so, we advance a sophisticated spatiotemporal flood-modeling approach -- expected annual exposure -- based on a probabilistic spatial envelope that unifies spatial extents between the high-tide line and the 10,000-year floodplain. We show that the effects from sea level rise will impact far more people far sooner than previously thought. In particular, our results suggest that single, binary extent assessments either underestimate or overestimate the magnitude of the at-risk populations while also spatially homogenizing the impacts to sea level rise. Our advance on modeling annual exposure provides a more robust and holistic assessment of the populations most at-risk to flooding from sea level rise. This typology can be used to guide new research connecting risk of sea level rise to related adaptation policies and planning.

scholarly journals Water and sediment yield estimation: A case study in Bawashaswar Watershed/ Iraqi Kurdistan Region

2021 ◽  
Vol 49 (1) ◽  
Author(s):  
Sarkawt G. Salar ◽  
◽  
Abdulhaq N. Mahmoud ◽  
Arsalan A. Othman ◽  
◽  
...  
Keyword(s):  
Sediment Yield ◽  
Assessment Tool ◽  
Ground Surface ◽  
Curve Number ◽  
High Water ◽  
Water Yield ◽  
Climatic Data ◽  
Wet Season ◽  
Runoff Water ◽  
Water And Sediment

Water flow in the seasonal streams forms a vital supplier of water resources, particularly in arid and semiarid areas due to its high water supply from the precipitation during the wet season. This research aims to estimate water and sediment yield in the Bawashaswar watershed (BW), which is far ~90 km from Kirkuk City and covers an area of 277 km2. The Bawashaswar Dam (BD) was constructed for multi-purposes, such as drinking, irrigation, livestock, and tourism at the outlet of the watershed north of Kifri town. The Soil Water Assessment Tool (SWAT) was integrated with several datasets, such as satellite images, Digital Elevation Model (DEM), land use, land cover, curve number (CN), daily climatic data of temperature, precipitation, and digital soil map to achieve the results. The estimated results include precipitation, evaporation transpiration, percolation, surface runoff, water yield, loss of transport, and sediment yield. The results showed that almost all the siltation (>0.5 ton/ha) comes from the western and northern parts of the BW due to the high topographic relief and the high channel discharge there. These results will support the future development plans and management of the watershed through mitigating and minimizing the size of the ground surface degradation problems all over the study area with increasing the lifespan of the BD.

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