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Doumouya, I., Dibi, B., Kouame, I.K., Saley, B., Jourda, J.P., Savane, I., and Biémi, J. Modeling of Favorable Zones for the Establishment of Water Points by Geographical Information System (GIS) and Multicriteria Analysis (MCA) in the Aboisso Area (South-East of Côte d’Ivoire). Environmental Earth Science, 67, 1763-1780, 2012.

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Article

Seasonal Assessment of Aquifer Vulnerability to Pollution in Garoua-Cameroon using the D.R.A.S.T.I.C Model

1Hydrological Research Center, P.O.Box: 4110 Yaounde

2Department of Geology, University of Buea, Buea, Cameroon

3National Water Resources Institute, Kaduna, Nigeria


American Journal of Water Resources. 2024, Vol. 12 No. 1, 12-23
DOI: 10.12691/ajwr-12-1-2
Copyright © 2024 Science and Education Publishing

Cite this paper:
Eyong Thomson Areakpoh, Akoachere Richard Ayuk II, Omogbemi Omoloju Yaya, Ntonga Jean Claude. Seasonal Assessment of Aquifer Vulnerability to Pollution in Garoua-Cameroon using the D.R.A.S.T.I.C Model. American Journal of Water Resources. 2024; 12(1):12-23. doi: 10.12691/ajwr-12-1-2.

Correspondence to: Eyong  Thomson Areakpoh, Hydrological Research Center, P.O.Box: 4110 Yaounde. Email: thomsoneyong@gmail.com

Abstract

Aquifers are the main sources of water in Garoua and due to a lack of knowledge of their vulnerability to contaminants for the management and protection of these aquifers, this study to assess their vulnerability to pollution within four hydrogeological seasons using the DRASTIC (Depth-to-water, net-Recharge, Aquifer-media, Soil-media, Topography, Impact-of-vadose-zones and hydraulic-Conductivity) model was a necessity. Depth to water (D) of 196 wells ranged from 0.2 to 11.87 m are assigned ratings of 5, 7, 9 and 10. Net Recharge (R) ranged between 0-35.4 mm/yr. with assigned rating of 1. Aquifer media (A) are alluvium, sandstone, granites, and gneiss with ratings of 10, 8, 10 and 7. Soil media (S) from 50 infiltrometer tests are sands, silty clay, clays and loam soils with assigned ratings of 1, 5, 7 and 10. Topographic (T) slopes from DEMs varied from 0% to 18% were classed into 7 ranges and assigned ratings of 1, 3, 5, 7, 8, 9 and 10. Impact of the vadose zone of sand, clay and gravel were assigned ratings of 3, 9 and 10. Hydraulic conductivity (C) from slug tests on 50 wells ranged from 0.12 to 0.7 m/day and was assigned rating of 1. The derivative DRASTIC scores of aquifer vulnerability to contaminants in Garoua were: 150 in the wet season, 146 in wet-dry season, 158 in dry season and 157 in dry-wet season. DRASTIC indices classified the area into a high vulnerability class in all seasons. These higher vulnerabilities to pollution could be due to porous sandstone formations, the presence of fractured gneisses and fractured granites. From single parameter sensitivity analysis, depth to water, aquifer media, topography and impact of the vadose zone layer tend to be the most effective parameters in the vulnerability assessment because their mean effective weights are higher than their theoretical weights. Highest vulnerabilities to pollution occur during the dry seasons; this is of particular importance since during these periods water is scarce thereby, decreasing the pollution opportunity as there is no transport medium into the aquiferous formations.

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