The spatio-temporal dynamic of land use in the Bonoumin and Gourou watersheds, over the last three decades (1990 to 2020), were analysed using Landsat images (1990, 2005 and 2020), remote sensing and a geographic information system (GIS). The main objective of this study was to analyse the impact of changes in land use in these two watersheds on stormwater runoff, which is responsible for flooding in the study area. The methodology adopted consisted of first downloading the Landsat images, which were then pre-processed, before undergoing several processes, leading to the classification and analysis of land cover dynamic. Maximum likelihood supervised classification was applied. Thus, the results of this classification showed that over the last three (03) decades, the impermeabilised surfaces in the two watersheds, represented by the medium and highly densified urban areas, have increased significantly, unlike the vegetated surfaces, which have decreased significantly. The increase in impermeable surfaces reduces the capacity for water to infiltrate the soil and increases the amount of runoff. The results also showed that in recent years, the upper reaches of the Bonoumin watershed have come under considerable anthropogenic pressure. This means that in a few years time, there will be a sharp increase in the amount of runoff water in the lowlying areas of this basin, and therefore an increase in the risk of flooding.

The objective of this study aims to evaluate the physicochemical quality of surface and well water based on measurements of Temperature (T°C), pH, Electrical Conductivity (EC), Suspended Matter (MES), Calcium (Ca2+), Magnesium (Mg2+), Sodium (Na+), Potassium (K+), Bicarbonates (HCO3-), nitrates (NO3-), nitrites (NO2-), ammonium (NH4+), Chlorides (Cl-), sulfactes (SO42-), orthophosphates (PO43-) in the Loka watershed. The physical parameters pH, EC and T were measured in situ with a WTW 3111 pH meter, a WTW 3110 conductivity meter and a WTW3110 oximeter. Chemical parameters, major elements, nutrient salts and heavy metals were all analyzed at the CIAPOL laboratory. The analysis of these parameters was carried out according to the protocol of Rodier 1994. The suspended solids (MES) were obtained by filtration on a fiberglass filter. The physicochemical analysis of the Loka watershed shows that the surface waters have an average temperature of 26.43°C. pH values vary between 5.5 and 6.8. Summary The objective of this study aims to evaluate the physicochemical quality of surface and well water based on measurements of Temperature (T°C), pH, Electrical Conductivity (EC), Suspended Matter The coductivity content is between 29 ÿS/cm and 116.2 ÿS/cm, which reflects weakly mineralized waters. Nitrate concentrations observed in surface waters vary from 0.24 mg/L to 1.95 mg/L. Also, well water has a pH varying between 6.55 and 8.9 with an average of 7.35. These waters are also weakly mineralized and have nitrate contents of between 0.2 mg/L and 1.04 m/L. The average values of the different physicochemical parameters are generally below WHO quality standards. As a result, surface and well water on the whole can be used for the supply of drinking water but environmental monitoring remains important.

Extreme flow events have had a significant impact on populations and their activities in recent decades. To reduce the impacts associated with their advent a analysis between extreme hydrological phenomena and climate variability is necessary. However, qualitative data accessing difficulties and explanatory variable definition of extremes hydrological phenomena limit extreme flows rate studies. This study proposes the analysis the variability of the floods and the low flows at the Bianouan hydrometric station. Thus, five (5) floods characteristics variables (QCX5, QXJA, F90p, F95p and F99p) and three (3) for, the low flows (VCN10, QJNA and F10p) were extracted daily flows from the Bianouan hydrometric station from 1 January1962 to 31 December 2005. The variability of these extremes has been studied by the trend analysis (linear regression) and of the stationarity (Pettitt and Hubert tests). The results show that for flood variables the negative trend is very significant and ruptures are observed in 1980. For low flow variables the negative trend is significant and the ruptures are observed in 1981. From this study, we can deduce that the ruptures observed in the rains and flows average in the end 1960s and early 1970s have affected later the extreme flows around the 1980s.

The department of Daloa is located in central-west of Côte d’Ivoire. It belongs to the Lobo river watershed, a part of the Sassandra river. Water supply of populations from the city is done by the river Lobo. This water resource is faced to the pollution of water quality. This pollution came from anthropogenic activities. This study is carried out to know the physico-chemistry quality of water from Lobo river Daloa. The hydrochemical and multivariate statistical analysis technics were used for the study. The results show that the water of Lobo river is acid with pH value which ranges from 6.6 to 6.9 ; with an average of 6.8. Water is fresh with a low electric conductivity value which range from 192.3 µS/cm to 316 µS/cm. The chimical facies of water is the hydrofacies of is HCO3>Mg2+> Ca2+. The mineralization of water from Lobo river is led by the contact water-rock and anthropogenic activities. The study presents the physico-chemical characteristics of water from Lobo River. It determined the potential sources of pollution of surface water. Then, the study ensures sustainable management of the resource.

The mining industry is a main sector for economic and social development of a country. However, this industry generates many negative impacts on human and biophysical environments. Located south-east of C

The workshop of the interdepartmental committee responsible for managing household waste in Abidjan (Ivory Coast) in 2007 showed that the landfill site should be chosen out of the coastal sedimentary basin to protect the groundwater of the Continental Terminal aquifer against pollution. Indeed, this aquifer provides the potable water to Abidjan populations and also assures uniformity of the price of water by the water company of the Ivory Coast. But, given the groundwater flow and the possibility of transfer of fluid between the discontinuous and continuous aquifers, is it possible that an activity taking place outside the coastal sedimentary basin of C