Varsha Gungoa ^* Seifu Kebede Gurmessa ^*

• University of KwaZulu-Natal, Durban, South Africa

This study is undertaken to investigate the impact of climate variability on groundwater quality in Mauritius. This is performed by analysing the physical and chemical water quality of the 5 main aquifers over eleven years. Temporal variation in water quality properties were compared to the Standardised Precipitation Index (SPI), the Dry Spells, the Standardised Evapotranspiration Index (SPEI) and other climate variables to gain insights to how precipitation control ground water quality. The results reveal that the SPI and the SPEI correlate very minimally with water quality indicators. Sulphate is the only water quality indicator that showed correlations of above 0.4 in aquifers 2 & 3 against a 12 month SPI. Sulphate alongside chloride showed what is termed "notable correlation" a concept termed axiomatically in this paper to accommodate correlations that fall above 0.3 when assessed against global climate modes ENSO & AAO respectively. These result signify that sulphate is the most sensitive water quality indicator to water quantity changes notwithstanding the modesty of the correlations. Heavy storms occurring during cyclones impact the groundwater quality with respect to conductivity, TDS, salinity and nitrate, although this could not be statistically tested given the lack of water quality indicators collected on the days that surround the storm, therefore the conclusion is made based on one storm event. The study revealed that individual correlations between climate indices and water quality variable is present but weak. However, the long term trend in the water quality is visible.