Land use dynamics in the context of variations in hydrological regimes in the upper Senegal River basin

Abstract

The objective of this study is to analisis the climatic vulnerability of water resources in the Senegal iver and Gambia basins. The study concerns the analysis of rainfall data, flow rates of Modis-Terra satellite images. Time series of study data are variable. The purpose of this study is to analysis climate vulnerability on water resources in the Senegal River and Gambia basins. It is based on the exploitation, on the one hand, of the chronicles of annual rainfall amounts and annual flows of the tributaries of the Bafing at the Bafing Makana station, from Senegal at the Bakel station, from Bakoye to Oulia and from Faleme to Kidira over the period 1955-2014 and, on the other hand, of Modis-Terra satellite images from 2007 and Modis-Terra from 2014. The calculation of rainfall and hydrometric indices and the application of statistical tests made it possible to analyze hydro-pluviometric variability in the Senegal River and Gambia basins. This variability is characterized by comparable fluctuations in precipitation and runoff. The break identified on the rainfall and hydrometric series from the late 1960s onwards resulted in a rainfall deficit of 12% to 18% and a flow deficit of 66% after the break. The analysis of land use maps based on satellite imagery has made it possible to identify the dynamics of land use. This dynamic is characterized by the regression of natural plant formations in favor of anthropogenic ones. Fields and fallows experienced the greatest expansion with a rate of 7.8%, bare soils (8.8%). However, the forest and savannah experienced a decline of (-10.35%) and water bodies (-0.2%) following the 2007-2014 period. The degradation of the vegetation cover is undoubtedly one of the factors contributing to the persistence of the relatively high level of hydrometric deficit in the upper basin.

Assessing impacts of climate variability and land use/land cover change on the water balance components in the Sahel using Earth observations and hydrological modelling

“…The three other studies simulated the surface runoff (SURQ) in different sub-catchments of SRB during recent periods. The results of the two studies carried out by Faty et al (2019) and Sun et al (2013) showed comparable surface runoff values with our study. Furthermore, the above mentioned three studies were carried out in small catchments in SRB, while in our study the SURQ was estimated for the whole SRB.…”

“…This evidence emerged in the three watersheds. Similar result was also reported by Faty et al (2019), particularly in the upper reach of SRB. This decrease in SURQ was also noted by Mahmood and Jia (2019) in the LCB.…”

“…The latter is a huge wetland in the basin, and its tributaries along the Middle Niger Left-Bank are sensitive to climate variability and LULC changes (Andersen et al, 2012;Descroix et al, 2009;Rameshwaran et al, 2021). The Senegal River basin experienced noticeable variations in hydrological responses due to intensive changes in LULC as well as climate variability, specifically the precipitation (Faty et al, 2019;Oyebande and Odunuga, 2010). These three huge basins represent an important topic of studies addressing LULC changes, climate variability, and hydrological responses.…”

Characterization of an area susceptible to floods and inundations in a medium size city in Southern Brazil

“…26 In Senegal and The Gambia, the rainfall deficit was estimated at 10%, in West Africa it reaches 20% to 25%, affected by droughts and land use, evidencing the need to consider climatic variables in the management of water resources. 27 In Bahia, a state in northeastern Brazil, a downward trend in rainfall in the historical series was also identified, indicating a change in the water pattern. 28 The study is replicable to other risk areas in Brazil and Latin America, where similar situations occur due to the climate variation.…”