Based on 2022 and 2023 hydrometric data and satellite images (Sentinel 2022, SPOT 2010), this study aims to present the Nokoué Lake and its channels’ re-cent hydromorphological characteristics. Integrating flow,...Based on 2022 and 2023 hydrometric data and satellite images (Sentinel 2022, SPOT 2010), this study aims to present the Nokoué Lake and its channels’ re-cent hydromorphological characteristics. Integrating flow, tributary morphology, and topography data determined specific power values along the axes studied. The values obtained range from 2.69 to 12.92 W/m2 for Ouémé River and 2.46 to 10.99 W/m2 for Sô River. The resulting water erosion on banks and bottoms is of linear, areolar, or gully and claw types. Lake bathymetry varies from -0.5 to -2.6 m (low flow period) and -1 to -4 m;in the Ouémé, Sô, and Totchè rivers, it varies from -5 m to -7 m, reaching -10 m at the Cotonou channel entrance (flood period). Bathymetric profiles reveal varied “U”, “V” and “Intermediate” bottom morphologies, influenced by erosion/sedimentation processes and human activities. The flow facies identified are lentic in the northern tributaries and lotic in the Cotonou and Totchè canals. Spatial analysis identified nine (09) thematic classes. In 2022, the surface area of the water body has increased from 274 km2 at low water to 280 km2 at high water, whereas in 2010 (a recent year of exceptional flooding), the surface area was 270 km2 at low water and 277 km2 at high water. Significant changes in land use are observed between 2010 and 2022. The floodplain area decreased slightly, from 421 km2 in 2010 (year of exceptional flooding) to 419 km2 in 2022. The evolution of land use shows a progressive expansion of the urban environment to the detriment of the natural environment. In the medium to long term, this trend could threaten the hydromorphological balance and even the existence of this important lagoon ecosystem.展开更多
This study is based on the hypothesis that the implementation of Integrated Water Resources Management(IWRM)tools in the Oueme watershed has not led to a systematic improvement in the degree of IWRM implementation in ...This study is based on the hypothesis that the implementation of Integrated Water Resources Management(IWRM)tools in the Oueme watershed has not led to a systematic improvement in the degree of IWRM implementation in the Oueme Valley in Benin.Methodologically,data were collected through a semi-structured survey of stakeholder families in the study area using snowball sampling.The tool used was the form developed by the United Nations to collect data to assess the level of IWRM implementation.The four(4)assessment criteria,each covering a key component of IWRM,are the enabling environment,institutions and participation,management tools and financing.The results obtained per criteria according to the stepwise methodology adopted reveal on average a degree of implementation of 40 on a scale of 0 to 100 in the Oueme basin.This value varies according to the geographical area and the factors considered.This study,which is a decision-making tool,provides a guide for governments to monitor the progress of integrated water resources management in their territory.展开更多
文摘Based on 2022 and 2023 hydrometric data and satellite images (Sentinel 2022, SPOT 2010), this study aims to present the Nokoué Lake and its channels’ re-cent hydromorphological characteristics. Integrating flow, tributary morphology, and topography data determined specific power values along the axes studied. The values obtained range from 2.69 to 12.92 W/m2 for Ouémé River and 2.46 to 10.99 W/m2 for Sô River. The resulting water erosion on banks and bottoms is of linear, areolar, or gully and claw types. Lake bathymetry varies from -0.5 to -2.6 m (low flow period) and -1 to -4 m;in the Ouémé, Sô, and Totchè rivers, it varies from -5 m to -7 m, reaching -10 m at the Cotonou channel entrance (flood period). Bathymetric profiles reveal varied “U”, “V” and “Intermediate” bottom morphologies, influenced by erosion/sedimentation processes and human activities. The flow facies identified are lentic in the northern tributaries and lotic in the Cotonou and Totchè canals. Spatial analysis identified nine (09) thematic classes. In 2022, the surface area of the water body has increased from 274 km2 at low water to 280 km2 at high water, whereas in 2010 (a recent year of exceptional flooding), the surface area was 270 km2 at low water and 277 km2 at high water. Significant changes in land use are observed between 2010 and 2022. The floodplain area decreased slightly, from 421 km2 in 2010 (year of exceptional flooding) to 419 km2 in 2022. The evolution of land use shows a progressive expansion of the urban environment to the detriment of the natural environment. In the medium to long term, this trend could threaten the hydromorphological balance and even the existence of this important lagoon ecosystem.
文摘This study is based on the hypothesis that the implementation of Integrated Water Resources Management(IWRM)tools in the Oueme watershed has not led to a systematic improvement in the degree of IWRM implementation in the Oueme Valley in Benin.Methodologically,data were collected through a semi-structured survey of stakeholder families in the study area using snowball sampling.The tool used was the form developed by the United Nations to collect data to assess the level of IWRM implementation.The four(4)assessment criteria,each covering a key component of IWRM,are the enabling environment,institutions and participation,management tools and financing.The results obtained per criteria according to the stepwise methodology adopted reveal on average a degree of implementation of 40 on a scale of 0 to 100 in the Oueme basin.This value varies according to the geographical area and the factors considered.This study,which is a decision-making tool,provides a guide for governments to monitor the progress of integrated water resources management in their territory.
