STUDY OF SURFACE WATER QUALITY DETERMINATION FOR IRRIGATION OF DINAJPUR SADAR UPAZILA, DINAJPUR

Abstract

An investigation was carried out to assess the suitability of surface water for irrigation purposes. For this reason 44 surface water samples were collected from each union of Dinajpur Sadar Upazila, Dinajpur. Analysis were done including pH, EC, TDS (total dissolved solids), cations (Ca2+, Mg2+, Na+ , K+ , Cu2+, Mn2+ and Fe3+) and anions (HCO3 - , SO4 2-, PO4 3- and Cl- ). Several computed variables such as SAR (sodium adsorption ratio), SSP (soluble sodium percentage), hardness (HT), permeability index (PI) and Kelly’s ratio were used to evaluate the suitability of surface water for irrigation purposes. Almost all the water samples were within the recommended pH value for irrigation and had a great impact on irrigation. No sample was excellent, 14 samples were good and 30 samples were permissible for irrigation purposes with respect to electrical conductivity (EC). For total dissolved solids (TDS) all samples were considered as fresh water for irrigation. Based on SAR values, all samples were classed as excellent categories for irrigation. On the basis of Ca, Mg, Na, K, Fe, Mn and Cu content the entire water samples can safely be used for irrigation and would not affect the soils. In the present study, no samples were considered hard while 25 samples were moderately hard and 19 samples were soft for irrigation purposes.