Statistical Study of Groundwater Salinity at Lake Dayet Erroumi, Morocco

Abstract

In the present study, descriptive and multivariate statistical techniques (principal component analysis) are used to investigate groundwater salinity in the area adjacent to Lake Dayet Erroumi. Nine groundwater samples were collected during September 2019 and analyzed for the following physicochemical variables: pH, EC, DO, Ca 2+ , Mg 2+ , Na + , K + , HCO 3- , Cl - , SO 4 2- and NO 3 -. Based on concentration averages, cation abundance is Na + > Ca 2+ > Mg 2+ > K + and anion abundance is Cl - > HCO 3 –> SO 4 2 - > NO 3- . Two principal components were selected on the basis of eigenvalue, which explains 71.39% of the total variance. The first principal component (F1) accounts for 52.37% of total variance and indicates water salinization, which depends on abiotic factors. The second principal component (F2) explains 19.01% of the information and indicates parameters dependent on biotic factors (DO and pH). Projection of the observations revealed two groups of wells: the first group comprises wells characterized by very high salinity, and the second group comprises wells with lower salinity. These results show that wells on the southern shore of the lake are more highly mineralized than other wells. The high mineralization of the groundwater is of natural origin, due to the leaching of Triassic evaporitic rocks.

Keywords

• salinity
• groundwater
• dayet erroumi
• descriptive statistics
• pca