Assessment of spatial and temporal changes in salinity and alkalinity of natural streams/nala water inSindhanur taluk of Tungabhadra command area in Karnataka

Abstract

The feasibility of quality of canal and natural stream/nala water for irrigation over the cropping season wasassessed from August 2019 to February 2020 in Sindhanur taluk of TBP command area. Water samples from twelvedifferent sampling stations along natural streams revealed that, EC of nala water varied from 0.14 to 0.30 dS m-1 as against0.44 to 7.39 dS m-1 of canal water respectively. Among cations, Na+ was the dominant followed by Ca2+, Mg2+ and K+. Therelative proportion of anions was in the order of HCO3- > Cl- > SO42- > CO32-. In general, the maximum variations in EC,concentrations of cations/anions and the SAR and RSC values in nala water among the sampling stations were observedparticularly in the months of December and February. Across the sampling stations, the mean EC(3.66 to 24.80), SAR (4.11to 19.41) and RSC (0.46 to 1.30) of nala were, higher compared to canal water over the cropping season. The EC, Cl/SO4ratio and SSP values are the major constraints in majority of nala water samples as far as their irrigation feasibility isconcerned