Assessment of quality of irrigation water in the central Narmada valley zone of Madhya Pradesh, India using GIS

Abstract

The water quality of the Central Narmada Valley Zone was assessed based on pH, electrical conductivity (EC), carbonate (CO3--), bicarbonate (HCO3-) chloride (cl-), sodium (Na+), calcium (Ca++), magnesium (Mg++), sodium adsorption ratio (SAR) and residual sodium carbonate (RSC). A total of 104 water samples were collected from Narsinghpur (n=28), Narmadapuram (n=42), Harda (n=28) district, some of only 6 and 2 water samples from Bareli and Raheti and analyzed. The pH ranged from 6.90 to 9.13, with a mean 7.89 indicating neutral to slightly alkaline conditions, within the FAO-recommended range for irrigation. The EC ranged from 0.22 to 0.96 dSm-1with a mean value 0.55 dSm-1, suggested moderate salinity levels, which are suitable for irrigation with some management practices. Carbonate and bicarbonate concentrations ranged from 0.40 to 3.60 meL-1 and 2.0 to 13.0 meL-1 with a mean value 1.26 meL-1 and 6.68 meL-1, respectively and both are within safe limits for irrigation. Chloride content varied from 2.00 to 14.00 meL-1 with a mean value 4.85, categorizing most samples as suitable for irrigation. Sodium adsorption ratio (SAR) and residual sodium carbonate (RSC) varied in study area and safe water. The concentrations of calcium (mean 2.37meL-1), Sodium (mean 2.0 meL-1) and magnesium (mean 1.63 meL-1) were within safe ranges and the calcium-to-magnesium ratio remained favorable for soil health. Overall, the results suggest that water quality in the Central Narmada Valley Zone is generally suitable for irrigation and varied in certain parameters, necessitating localized management strategies to optimize water use for agricultural purposes.