Characterization of coastal water bodies for irrigation in Udupi district of Karnataka

A study was conducted in 2022-23 to characterize the coastal water bodies of Udupi district for optimal irrigation use. Fifty-one representative water samples were randomly collected from various geographical locations between April and May 2022. These samples, taken from the sea, bore wells, lakes, open wells, rivers, and streams across the study area, were analyzed and categorized into different water quality classes according to standard procedures. Geographical coordinates were recorded at each sampling site. The frequency distribution of water samples based on pH revealed that the highest percentage (52.94%) fell within the pH range of 6.5-7.3 (neutral), followed by 29.41% in the 7.3-7.8 range (slightly alkaline), 1.96% in the 6.0-6.5 range (slightly acidic), 1.96% in the 5.5-6.0 range (moderately acidic), and 13.73% in the 7.8-8.4 range (moderately alkaline). This indicates that the water samples predominantly ranged from neutral to slightly alkaline, suggesting no potential alkali hazard when using this groundwater for irrigation. Regarding electrical conductivity (EC), 7.84% and 31.38% of the samples had EC values of 4 dS m-1, respectively. However, at all levels of ECiw, the mean Mg/Ca ratio was higher than 0.63, and the mean chloride content was higher than 4.0 meq L-1 in the study area. According to the CSSRI guidelines, 66.67%, 19.61%, 11.76%, and 3.92% of the samples were classified as having good, high SAR saline, saline, and marginally saline water quality, respectively.