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Journal of Geoscience and Environment Protection 2017年第3期5卷 252-264页

作者： Rel Dechangue Tatou Veronique Kamgang Kabeyene guillaume ewodo mboudou Department of Earth Science University of Maroua Maroua Cameroon University of Dschang Dschang Cameroon Department of Hydraulic and Water Management University of Maroua Maroua Cameroon

The determination of the processes responsible for the mineralization of ground-water requires a large number of samples and physicochemical data, the treatment of which proves to be tedious. Many statistical methods are developed to facilitate the treatment of a certain volume of data. In this study, multivariate statistical analysis including principal components analysis (PCA) and hierarchical cluster analysis (HCA) have been applied on the groundwater physicochemical data of the upper Kambo watershed. The aim is to simplify the data in order to evaluate the relationships between the parameters and also to detect the factors that influence the water chemistry. For the PCA, three factors were retained representing 70% of the total inertia. Factor 1 shows the heterogeneity of sources of acquisition of the mineralization by the positive correlation with all the variables. Factor 2 indicates the dissolution of carbonates and anthropogenic input. Factor 3 highlights the silicate, anthropogenic and atmospheric or marine origin. The HCA enables to differentiate 4 groups of water according to the degree of mineralization. Groups 1 and 2 represent the most mineralized waters, dominated by calcium. The poor mineralized waters are groups 3 and 4 with the rather close contents in calcium and sodium.

关键词： Principal Component Analysis Cluster Analysis Groundwater Upper Kambo Watershed Douala

Hydrochemistry of Groundwater in the Rice Cultivation Area of Maga: Analysis of the Mineralization Process

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Journal of Geoscience and Environment Protection 2024年第9期12卷 370-387页

作者： Emmanuel Aguiza Abaï Hugues Pahimi Prosper Samba Koukouare guillaume ewodo mboudou Auguste Ombolo Department of Industrial Security Quality and Environment National Advanced School of Mines and Petroleum Industries University of Maroua Kaele Cameroon School of Chemical Engineering and Mineral Industries University of Ngaoundere Ngaoundere Cameroon Department of Hydrocarbons Exploitation Mao National Higher Petroleum Institute NDjamena Chad Department of Hydraulics and Water Management National Advanced School of Engineering of Maroua University of Maroua Maroua Cameroon Department of Rural Engineering Higher Institute of Agriculture Forestry Water and Environment University of Ebolowa Ebolowa Cameroon

The use of groundwater for drinking water supply to the population is increasingly practiced in the rice cultivation area of Maga. However, there is a lack of knowledge about the hydrochemical characteristics of this water due to a lack of quality control. This study aims to contribute to the understanding of mineralization processes in order to establish the hydrochemical profile of the water in the area. The methodological approach consisted of collecting fifteen water samples from wells and boreholes during six campaigns for physicochemical analysis, and studying them through methods of interpreting hydrochemical data. The analysis results show that these waters are moderately mineralized. The water facies are mainly of the bicarbonate sodium and potassium type, as well as the bicarbonate calcium and magnesium type. Calculation of saturation indices demonstrates that evaporite minerals show lower degrees of saturation than carbonate minerals, with gypsum, anhydrite, and halite being in a highly undersaturated state. The mineralization of groundwater originates from the dissolution of surrounding rocks on the one hand, and anthropogenic activities involving exchanges between alkalis (Na+ and K+) in the aquifer and alkaline earth (Ca2+ and Mg2+), resulting in the fixation of alkaline earth and the dissolution of alkalis.

关键词： Hydrochemistry Mineralization Groundwater Maga

Trends and Geostatistical Interpolation of Spatio-Temporal Variability of Precipitation in Northern Cameroon

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American Journal of Climate Change 2016年第2期5卷 229-244页

作者： Elisabeth Fita Dassou Auguste Ombolo Steven Chouto guillaume ewodo mboudou Jean Marcel Abate Essi Etienne Bineli Department of Climatology Hydrology and Pedology Higher Institute of Sahel University of Maroua Maroua Cameroon Department of Hydraulics and Water Management Higher Institute of Sahel University of Maroua Maroua Cameroon Department of Environmental Sciences Higher Institute of Sahel University of Maroua Maroua Cameroon Institute for Geological and Mining Research (IRGM) Center for Geological and Mining Research Garoua Cameroon

This paper examines the spatial and temporal variability of the mean annual precipitation in the Northern Cameroon on the context of climate change during the time period 1950-2013. The study used homogeneous monthly and annual precipitations database of twenty-five stations located in the Northern Cameroon and Southern Chad Republic. Geostatisticals interpolation methods (Kriging and Inverse Distance Weighting method) associated with Digital Elevation Model were used to establish the spatial distribution of annuals precipitations. The non-parametric Mann- Kendall test and Sen’s slope method were performed to determine respectively trend and magnitude. The result indicates a spatial distribution of precipitation mainly determined by the topography and the geography of the study area. The trend analysis shows a decrease of annual average precipitation across the Northern Cameroon at a rate of ?0.568 mm/year over the time period 1950-2013. The magnitude of decreasing trends ranged between 0.11 and 3.92 mm/year. Statistically significant decreasing trends at the 95% level of confidence were noted at 10% while 5% of stations showed statistically significant increasing. However, 60% of stations indicate a decreasing trend. Monthly analysis of rainfall shows a decreasing trend during June and September while July and August present an increasing trend.

关键词： Precipitation Kriging Inverse Distance Weighting Mann-Kendall Test Trends Northern Cameroon

Estimation of Hydraulic Conductivity of Soils at a Watershed-Scale Using Porchet’s Method: Application in the Olezoa Waterhed, Yaounde, Cameroon

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International Journal of Geosciences 2016年第3期7卷 397-408页

作者： André Firmin Bon Auguste Ombolo guillaume ewodo mboudou Jules Rémy Ndam Ngoupayou Georges Emmanuel Ekodeck Department of Climatology Hydrology and Soil Science Higher Institute of the Sahel University of Maroua Maroua Cameroon Department of Earth Sciences Faculty of Science University of Yaounde I Yaounde Cameroon Department of Hydraulics and Water Control Higher Institute of the Sahel University of Maroua Maroua Cameroon

Contamination analysis of the unsaturated zone requires information on the spatial variability of hydraulic conductivity. Two types of hydraulic tests (variable and constant charge) were identified to estimate the spatial variability of the hydraulic conductivity of the surface portion of the unsaturated zone in the Olezoa watershed. These tests were performed on 100 holes at depths ranging between 50 and 90 cm, spread throughout the watershed. The hydraulic conductivity values obtained at 50 and 90 cm are close to the absolute value for each method. However, they show a difference of 10-1 m/s between the two types of test regardless of the depth of investigation. The representation of data in the graph indicates a staircase quartile distribution for the variable charge test. The test at constant charge, rather presents a log normal distribution which is also supported by the Kolmogorov-Smirnov test. Hydraulic conductivities have a random component and a spatial organization which results from soil and/or morphological factors. This organization thus permits the distinction of zones which could show high pollution risk.

关键词： Unsaturated Zone Quartile Graphs Hydraulic Conductivity Olezoa