ASSESSMENT OF GROUNDWATER QUALITY AND SUITABILITY FOR IRRIGATION PURPOSES AT NAGESHWARI UPAZILA

Abstract

A study was conducted to evaluate the quality of groundwater in different unions of Nageshwari upazila under Kurigram District of Bangladesh for irrigation purposes. Forty water samples were collected and analyzed in the Agricultural chemistry laboratory of Hajee Mohammad Danesh Science and Technology University for the assessment of their quality based on a number of pH, total dissolved solids (TDS), electrical conductivity (EC), sodium adsorption ratio (SAR), Kelly‟s ratio (KR), residual sodium carbonate (RSC), soluble sodium percentage (SSP), total cations (Ca2+, Mg2+, Na+ and K+) and anions (HCO3-, SO4 2, PO4 3- and Cl-). Several computed variables such as SAR (Sodium Adsorption Ratio), HT (Total Hardness), PI (Permeability Index), PS (Potential Salinity) and Kelly‟s Ratio were used to evaluate the suitability of groundwater for specific uses. Most of the water samples were slightly acidic in nature (pH value varied from 5.88 to 7.15 for ground water) and had a great impact on crop production. As regards to EC values, 21 samples were classed as „good‟ and 12 samples were classed as „excellent‟ and 7 samples were „permissible‟ categories for irrigation. All samples were fresh for irrigation in respect to TDS. Based on SAR values, all water samples were under „excellent‟ categories for irrigation. On the basis of Ca2+, Mg2+,Na+ and K+ content, the entire water samples can safely be used for irrigation and would not affect the soil +. On the basis of PO4 3, SO4 2-, HCO3- and Cl-, all water samples under investigation were suitable for irrigation. For hardness, 7 samples were soft, 28 samples were moderately hard and 5 sample were hard for irrigation. Some compositional relations were also evaluated. The results also provided data for water quality of groundwater resources of study region to match national and international standards for agricultural requirements. The study revealed that the quality of groundwater for most of the locations in the area was permissible, good and suitable for irrigation purposes.