Hydrogeochemical Assessment of Groundwater in the Koloran Valley Basin

Abstract

This study addresses the hydrogeochemical assessment of groundwater from nine wells within the Koloran Valley Basin – Sulaymaniyah Governorate. The basin lies within the Said Sadiq and Penjwin districts, between the geographical coordinates of latitude (35°36′N – 35°17′N) and longitude (46°05′E – 45°40′E), with a total area of 312.89 km². The results indicate that, according to the hydrochemical formula, the dominant water type falls within the (sodium–chloride) class (Na⁺ – Cl⁻), originating from saline sources due to the dissolution of halite (rock salt, NaCl) layers in the aquifer formation. The hydrogeochemical processes affecting groundwater cations are predominantly governed by rock weathering (rock dissolution), while anions are jointly influenced by evaporation, rock dissolution, and precipitation. Application of the Piper diagram reveals that the water is sodium–chloride type (Na – Cl), with non-carbonate alkalinity exceeding 50%. The water composition is dominated by alkalies and strong acids, which are more prevalent than weak acids, and exhibits ongoing ion exchange due to continuous chemical interaction with soils and rocks, with low solubility. All groundwater samples are suitable for drinking, irrigation, and construction purposes.