The variations in rainfall patterns observed in recent years in the north-western part of Guinea are well prefecture of Siguiri in Upper Guinea. In order to understand the trends in rainfall and hydrometric variations, we used the Standardized Precipitation Indices (SPI) method. The remote sensing method applied reflects human causes in the transformation of environmental environments (water, forests, soils, habitats, crops). The results obtained show that rainfall over the period 1981-2020 is marked by periods of deficit (drought) between 1981-1993; 1998-2002 and 2013-2020, while wet periods (surplus) occur between 1994-1997 and 2003-2012. Fluctuations in annual flow modules can be explained by a surplus period from 1980 to 2000 and a deficit period from 2001 to 2019. The statistics drawn from the land-use maps for 2000, 2010 and 2021 highlight the spatial and temporal dynamics of each thematic class. From 2000 to 2021, the Water/Wetlands (+22.55%) and gallery forests (+23.92%) classes show increases, while the Bare Soil/Cultivated Land (-20.08%), Wooded Savannah (-4.55%) and Savannah-Crop Mosaic (-21.85%) classes show decreases. Temperatures between 1981 and 2022 in the Siguiri area varied between 25.995°C and 27.72°C, with the highest values recorded in 2010.

The surface water resources in the region of Bonoua are subject to strong anthropogenic pressures created by the development and expansion of agricultural activities and also by the agro-industrial and domestic activities. This impacts the available quantities of these resources that fluctuate throughout the year. Similarly, their quality is thereby also changed. Regarding the quality of these resources how can occur at a given time of year? This concern led in this study to assess the overall quality of surface waters of Bonoua region during the rainy season. It is based on the exploitation of data from a water sampling campaign conducted in July 2014. The data were processed with the Evaluation System of Quality of Waters, referred to as "SEQ-Eau" for determining the overall water quality. The (ACPN) has also been applied to the data for the identification of phenomena causing water pollution. The results show that in general the surface waters in the region are Bonoua of "average quality" to 92.86% and "poor" at 7.14%. The responsible alteration of this deterioration in the quality of surface water is the "acidification" parameter, which contributes to 64%. Alterations "temperature" and "organic and oxidizable materials" expressed as COD and BOD 5 incidentally involved in this deterioration in the respective proportions of 14 % and 22 %. The phenomena causing water pollution is anthropogenic. They are mainly from discharges of domestic and industrial waste water and the use of chemical fertilizers in the plantations. This evaluation of the quality of surface water in the region of Bonoua is a first draft that should be complemented by other studies covering aspects such as pesticides and microbiology for better management.

The led study presents the current state of the quality of waters of the tablecloth of Bonoua as well as its situation towards polluting elements of anthropological origin (NO3-, Cl-, NH4 +). This tablecloth is more and more requested to cover the water requirements of the city of Abidjan, while its quality is felt (experienced) by the diverse sources of pollution which multiplied further to the urbanization and to the development of the agro-industrial cultures.
To estimate the current subterranean quality of waters of this tablecloth a comparison and a follow-up of its physico-chemical parameters from 2001 till 2015 was realized. It was coupled with a multivariated statistical analysis to know the Analysis in Main Component (ACP) to determine the origin of mineralization, The methodology took into account on one hand the hydrochemical parameters which showed that waters are acid with a pH between ((4,2UpH and 6,88UpH, more important concentrations in nitrates (140mg / L) to Ahoutou