Assessment of quality and suitability of groundwater resources for industrial and irrigation purposes, Dire Dawa, Ethiopia

Abstract

The groundwater demand of Dire Dawa has increased recently due to the expansion of irrigation and the industrial sector in the city. Groundwater used for irrigation and industry was studied. Eighty-two samples were used to analyze physicochemical using different indices like Langelier index (LSI), Ryznar index (RSI), Aggressive index (AI) and Larson-Skold index (LRI). Parameters of Sodium Absorption Ratio (SAR), Residual Sodium Carbonate (RSC), Dissolved Sodium (%Na), Magnesium hazard (%Mg) statistical and spatial distributions were analyzed and programmed with Excel, Arc GIS, and Diagrams software. Results showed that pH, Mg²⁺, Cl^- were found to be within the limit for industrial use. The groundwater corrosion indices mean values of LSI, RSI, AI, and LRI obtained were 0.29 ± 0.28, 6.4 ± 0.5, 12.20 ± 0.24 and 1.4±1.57, respectively. LSI, RSI results indicated a moderate scale-forming tendency of the groundwater. AI values were within low to no corrosion rates in all zones. Because of Cl^- and SO₄^2-, LSI showed some localized corrosion properties at kebele 01 and 09. Parameters like pH, Conductivity, Na⁺, HCO₃^- and Cl^- ion were within permissible limits for irrigation. The irrigation indices (meq/l); SAR, RCS, Na% and Mg Hazard were calculated to be 1.33, -2.17, 21.5%, 45%, respectively. The EC was within the permissible limit but was significant. The low values of SAR, RCS, Na% indicated that the groundwater can cause lower alkalization (Sodium hazard) effect. In conclusion, all the parameters of the groundwater sources were categorized as good for irrigation. However, corrosion indices elaborated the groundwater scaling problems and may also be aggravated with temperature and heat-related industrial equipment.