Evaluation of the impacts of climate change and land-use dynamics on water resources: The case of the Lobo River watershed: Central-Western Côte d'Ivoire

Abstract

<p>Meeting growing water needs in a context of increasing scarcity of resources due to climate change and changes in land use is a major challenge for developing countries in the coming years. The watershed of the Lobo river in Nibéhibé does not escape this dilemma. The water retention of the Lobo River and its watershed play an important role in the subsistence of the inhabitants of the region. However, the watershed is currently subject to strong human pressures mainly associated with the constant increase in human population and intensification of agricultural activities. The main objective of this study is to assess the impacts of climate change on the water resources of the Lobo River watershed at Nibéhibé in the central-western part of Côte d'Ivoire. Two climate change scenarios (RCP4.5 and RCP8.5) were established using the regional climate model RCA4 (Rossby Centre atmospheric model 4) and the flows under these scenarios were simulated by the hydrological model CEQUEAU with respect to a reference period (1986-2005). The RCA4 regional model predicts an increase of 1.27° C; 2.58° C in the horizon 2021-2040 and 2051-2070 in mean annual temperature. Rainfall would also experience a significant average annual decrease of about 6.51% and 11.15% over the period 2021-2040 and 2041-2070. As for the evolution of flows, the Cequeau model predicts a decrease in the runoff and infiltration of water on the horizon 2021-2040 and an increase in evapotranspiration over time according to the RCP4.5 scenario. However, the model predicts an increase in runoff at the expense of a decrease in REE and infiltration at the horizon 2040-2070 according to scenario RCP8.5. It appears from this study that surface flows and infiltrations, which constitute the water resources available to meet the water needs of the basin's populations, will be the most affected. The results obtained in this study are important and could contribute to guide decision making for sustainable water resource management.</p>

Estimation of Groundwater Recharge in the Lobo Catchment (Central-Western Region of Côte d’Ivoire)

“…Then, the coefficients of this equation are used to derive the MRC, and finally, to determine the recession index (K), which represents the recession rate in days per log cycle. The critical time Tc, representing the time at which the recession becomes linear, can be determined from Equation (1). The detailed procedure for this process is given in [21].…”

“…representing the time at which the recession becomes linear, can be determined from Equation (1). The detailed procedure for this process is given in [21].…”

“…The city and its surroundings are supplied with drinking water from the Lobo reservoir. This resource is crucial for these localities but is currently threatened by overexploitation and siltation [1] and is highly eutrophic due to multiple sources of pollution. Due to the poor quality of the water supplied to the population, repeated interruptions in supply, overexploitation, and reduction in inflow to the river [1], exploitation of groundwater is necessary to improve the supply of drinking water.…”

“…This resource is crucial for these localities but is currently threatened by overexploitation and siltation [1] and is highly eutrophic due to multiple sources of pollution. Due to the poor quality of the water supplied to the population, repeated interruptions in supply, overexploitation, and reduction in inflow to the river [1], exploitation of groundwater is necessary to improve the supply of drinking water. However, predicting the duration of possible exploitation and the flow associated with it requires an assessment of the renewal of the resource, i.e., the recharge.…”

Identification of hydrogeological and geoelectrical parameters influencing the productivity of boreholes in the commune of Daloa (Central-Western of Côte d'Ivoire)

“…The Lobo underground reservoir supplies drinking water to the Daloa population, as are most of the country's towns in crystalline rock. Nowadays, the negative effects of climate change led to serious water problems in Daloa, the third largest city in Côte d'Ivoire and the economic center of all the localities in the Lobo catchment area [ 1 ]. Daloa is a university town where the population grows at a rate of 3.71 % yearly [ 2 ].…”