Climatic variability in the Sine-Saloum basin and its impacts on water resources: case of the Sob and Diohine watersheds in the region of Niakhar

Abstract

Abstract. Local peoples from Niakhar in the Senegalese peanut basin highlight a dramatic increase of water access problems due to marked rainfall deficits and salinization of surface and ground water resources. The chemical quality of groundwaters is often critical because of the salinization process, whereas water surfaces, which should be used in such situations, are up early. More and more, lowlands and rivers beds are pervaded by salt crusts. Then the salinization of wells is increasing, leading to the extension of tans (salty of acidified soils). To study the impacts of climatic pejoration on the agroecosystems and on the living conditions of the populations, we carried out the analysis of the time series of the precipitations with daily and annual time steps from 1950 to 2015 on 6 meteorological stations, in situ measurements on 78 wells for an area of 311 km2, as well as local population interviews and field observation. The results confirm an important climatic break in the region in 1970. The long dry period, from 1970 to 2009, has increased the annual rain variability, decreased the number of rainy days per year. We confirm a real and large extension of well salinization, and salt crusting in the lowlands and the riverbeds. From the local people, it seems the process of degradation of the aquifers continues to progress from a large tidal event in 1984. The rainfall increase noted in the last decade does not seem to be enough to reverse the trend and to ensure both the rise of the piezometric level of the aquifers and the desalinization of surface and ground waters.

Monitoring land use and soil salinity changes in coastal landscape: a case study from Senegal

“…4 ). Historical evidence may explain this finding, since that period was characterized by an increasing resource pressures and land degradation due to severe events such as drought (Sadio & van Mensvoort, 1993 ; Faye et al, 2020 ).…”

Estimating water fluxes in the critical zone using water stable isotope approaches in the Groundnut and Ferlo basins of Senegal

“…With these PSD results as inputs, the GRADISAT V9.1 package (Blott, 2001) was used to compute the fractions of sand, silt, and clay, and thus to classify the soil textures according to the USDA. For Site 2, we used soil‐texture data from Faye, Diallo, et al (2020), Faye, Fall, et al (2020), which covered the 0–100 cm depth on the mid‐slope locations as well as on the lower‐slope locations, near the pond.…”

Root litter decomposition in a sub-Sahelian agroforestry parkland dominated by Faidherbia albida

“…Soil moisture is a key factor controlling root decomposition and seems to be the main driver of decomposition kinetics after litter species, i.e., quality (Arrouays et al, 2002;Butenschoen et al, 2011). Because the humidity of the root litterbags was significantly higher for the individuals located under the tree due to tree shading, which reduced soil evaporation (Hasselquist et al, 2018), greater soil water infiltration (Faye et al, 2020), the reduction of water runoff under the tree crown (Lal 1989) and the potential benefit of hydraulic redistribution through the Faidherbia root system (Bayala and Prieto 2020), we expected a slower fine root decomposition rate far from the tree than under the tree. This was not confirmed here.…”