Groundwater potential zone mapping by combining remote sensing, modified DRASTIC method and field data for Bidou I, South Cameroon

2024

Article référencé dans le Web of Science WOS:001195144200001

Njikeu O., Feumba R., Tchouta K. D., Deschamps Pierre, Ngatcha B. N.

Sustainable Water Resources Management, 2024, 10 (2), 100 [23 p.] ISSN 2363-5037

Assessment of groundwater resources in southern Cameroon by remote sensing techniques is almost non-existent, and therefore limit knowledge on the groundwater potential in Cameroon. This work aims to delineate groundwater potential zones (GWPZ) in Bidou I, made up of metasedimentary rocks. To achieve this work, interpretation of Landsat 8 OLI/TIRS collection_2, Level_2 and SRTM images coupled with fieldworks and climatic data was done. A total of 2,370 lineaments were mapped ranging between 60 and 4498 m, with an average of 525 +/- 420 m for a total length of 1244 km. Eight lithological types were identified showing three phases of deformation. Two major fractures (N-S and WNW-ESE) cross-cutting each other were identified and can be filled by quartzite injections bearing sulphides. The major directions of fractures are consistent with those of the Kribi-Campo shear zone. This clearly demonstrates that groundwater flowing directions lie between N330 degrees-N045 degrees E with an average direction N010 degrees E, corresponding to the recharge direction of almost all frequently renewed aquifers. The stock variation (Delta Ri) equivalent to the effective recharge from 1991 to 2021 implies an effective infiltration of about 10% of the total rainfall in the region (2957.0 mm/year). The pores filtration rates vary from 0.5 x 10-9 to 11.0 x 10-9 m/s with an average of 2.5 x 10-9 m/s depending on the state of the rock (fractured or weathered). Soils, slopes, geological, geomorphological, drainage density and lineament density maps were realized for the study area leading to a reference map of GWPZ showing five classes (very poor, poor, moderate, good and very good), obtained by assigning a fixed weight and a score to each layer, calculated from DRASTIC model modified, using weighted overlay analysis (WOA) tool. These maps can help for drilling programs as well as sustainable groundwater management in the area, mining prospecting mission and for a better interpretation of geological structures from the field.

Hydrologie [062] ; Géologie et formations superficielles [064] ; Télédétection [126]

CAMEROUN

Fonds IRD [F B010090512]

fdi:010090512