Reconnaissance on the suitability of the available water resources for irrigation in Thakurgaon District of northwestern Bangladesh

Reconnaissance on the suitability of the available groundwater resources for irrigation in Thakurgaon District of northwestern Bangladesh was done by determining pH, TDS, EC, hardness, alkalinity, major cations and anions. The pH values suggest that the water is slightly acidic to strongly basic. The dominant cation and anion in the study area are Ca 2+ , Mg 2+ and HCO 3 − , respectively. Calcium bicarbonate, calcium–magnesium–bicarbonate and calcium carbonate are the dominant hydrochemical facies among the water samples. The groundwater system in the study area may be recharged through infiltration of rain. The above statement is further supported by Gibbs plot where most of the samples fall within the rock-dominance zone. The evolution of these waters may be controlled by precipitation and dissolution of carbonate minerals. The USSL, SAR–EC classification schemes and Wilcox plot confirm that the groundwater samples are good to excellent as irrigation water. However, the groundwater evolution in this study is mainly the result of weathering of carbonate minerals and cation exchange within the aquifer materials, confirming the shallow porous groundwater hydrochemistry characteristics.