USING PRINCIPAL COMPONENTS ANALYSIS, SO/Cl- AND Mg2+/Ca2+ RATIOS TO DELINEATE THE MAIN WATER BODIES IN THE COASTAL AQUIFER OF AGADIR, SOUTHWEST MOROCCO

Descriptive statistics, correlation matrix and Principal Components Analysis (PCA), together with major ions data were used to gain an understanding of the hydrochemical processes of groundwater in the coastal aquifer of Souss, Morocco. The aquifer is made of various deposits: sandstone and shelly limestone near Agadir city, marly limestone in the left bank of Souss wadi, conglomeratic formations in the right bank of Souss wadi and finally sandy and alluvial formations in sand hills zone.

The use of electrical conductivity (EC), SO₄^2-/Cl^- and Mg²⁺/Ca²⁺ molar ratios has allowed us to distinguish between three types of waters: (1) Na-Cl type which characterises the area around Agadir city and in which high salinity is basically due to marine influence; (2) Na-Cl type but with relatively high contents of sulphates which concerns the area of Aït Melloul city, 10 km far from the ocean. The main processes influencing groundwater quality in this area are marine influence, evaporite rock dissolution, and agricultural activities; and (3) Ca-Mg-HCO₃ type which prevails in the upland portions of the study area and in southern coastal sand hills in which waters are fresh, indicating recharge occurring in these areas.