The aim of this work is to identify and enhance the value of lowlands in the face of the challenges posed by climatic hazards, with a view to the sustainable use of land that represents a major challenge for agriculture in Ivory Coast. The data used in this study are sentinel-2 images for the year 2023. The various methodological approaches used consisted of the combined extraction of vegetation, moisture and topographical indices. Analysis of the results shows that our study area has lowlands covering an area of around 31,100 ha. In the department of Man, 121584 ha of wetlands have been inventoried, covering 12% of the territory. They offer opportunities for a variety of crops, particularly rice and market gardening, and play a crucial role in food security and people’s livelihoods. However, their use faces challenges linked to climatic hazards, water management constraints and land pressure from urban expansion. Lowlands benefit from higher humidity and soils that are often rich in nutrients, which encourages crop growth. Farming in these areas contributes to local food security and can generate additional income for households. At times, these areas are prone to flooding and drought, which can lead to crop losses. It is important to manage these different plots in a sustainable way, taking into account the needs of the local population and the preservation of the environment. This work highlights the effectiveness of the remote sensing-GIS approach for monitoring wetland ecosystems and strategies for adapting to climate change.

Understanding the necessary relationship between the radar reflectivity factor Z and the rain rate R is still important today and constitutes an interesting challenge for the scientific community. Despite this interest and the advances already obtained in this field, understanding the variability of this Z-R law is not yet trivial. This work therefore consists of studying the implication of rain spectra at low intensities R≤1mm/h in this variability. Thus, from a large historical database of raindrop size distribution (DSD) acquired in tropical Africa, we have shown that rain spectra R≤1mm/h lead to high values ​​of the coefficients A and b of the Z-R power relationship. However, the variability of pre-factor A is pronounced in agreement with those of the NT and D0/NT parameters of the DSD; while the exponent b remains quasi-constant in such rainy samples, independently of their percentage. Establishing the link between the observation parameters D0, NT and D0/NT of the DSD and the pre-factor A of the Z-R relationship made it possible to arrive at close power relationships D0 – A, NT – A and D0/NT – A corresponding respectively to the microphysical modes «D0 constant, NT variable», «D0 variable, NT constant» and «D0 variable, NT variable». The last microphysical condition seems to be more suited to the power relationship A – α where α, is the pre-factor of the power relationship D0/NT – R found in the literature.

The aim of this study is to highlight the combined effects of climate change and anthropization on surface waters in the Agnéby watershed. The global hydrological balances produced by the SWAT model show that in the year 2050, precipitation will record a deficit of 1.87%, while actual evapotranspiration will be 2.80% higher. Groundwater recharge and runoff will be in deficit by 2.5% and 9.77% respectively, and stock variation will be in deficit by 36.62% compared with the reference period. For 2080, precipitation, groundwater recharge and runoff will be in deficit by 1.23%, 1.5% and 10.23% respectively. Actual evapotranspiration will show an excess of 3.37%, and the change in stock relative to the reference period will also show a deficit of 20.42%. The hydrological consequence of this state of affairs is the depletion of surface water resources over the years in the Agnéby watershed due to anthropogenic activities. The predominance of evapotranspiration can be explained by the fact that the area will be covered by large-scale farming operations. These could also be explained by the fact that the area will be less favorable to surface runoff than to infiltration.

This study was conducted to estimate the water requirement of the plant Lippia multiflora MOLDENKE. (Verbenaceae), also known as the bush tea or Gambia tea. Seeds initially germinated, are transplanted into pots of 14.5 cm high and 8.5 cm in diameter, completed soil indoors. The treatment consists of 5 parts water, I1, I2, I3, I4 and I5, respectively, for 15, 30, 50, 70 and 100 per cent of the usable reservation made by spraying the plants, for 3 months. Weighing pots with plants were made before and after watering, to calculate actual evapotranspiration (ETa).
The results show that actual evapotranspiration of Lippia multiflora, nursery ranges from 0.5 mm.d-1 to 2 mm.d-1. Plants with the irrigation dose, received I1, have a low ETR for the 3 months, followed by I2. Irrigation doses I3, I4 and I5 indicate ETR ranging from 1 mm to 2 mm per day. The crop coefficient in nursery phase is 0.32 for the month of May and 0.23 in July.
Regarding the vegetative growth, the results obtained show that, it is the I3 or I4 irrigation doses which allow a homogeneous development of the plants. These doses are thus, considered the maximum evapotranspiration of Lippia multiflora. And Culture of Lippia multiflora, it is necessary to go through the nursery phase by providing 50 or 70 per cent usable reserves of soil for optimal growth.