Temporal evaluation of surface water quality in semiarid regions: a case study of the Ouled Mellouk dam in north-western Algeria

Abstract This work aimed at evaluating the impact of human activity and geology on surface water quality Ouled Mellouk dam (northwestern Algeria). Specifically, methodology aims to assess seasonal variations several parameters (EC, TDS, pH, SO42−, Cl−, Ca2+, Na+, HCO3−, NO3−, PO43− Mg2+, organic matter, suspended solids, BOD5, COD) from 2007 2013 define processes controlling mineralization pollution water. The results show high salinization recorded during periods heavy precipitation or flooding, due leaching dolomitic limestones evaporitic deposits saliferous formations surrounding mountains. High concentrations NO2−, NH4+, matter can instead be attributed use fertilizers in agriculture. Moreover, PCA application shows that (49.92%), anthropogenic (19.38%) agricultural (12%) are most significant degradation factors, respectively. saturation index carbonates gypsiferous minerals precipitate before minerals, which allowed chemical elements coming dissolution gypsum halite acquire contents. In addition, evolution biological oxygen demand slight