Evaluation of River Chenab water quality with respect to its users, using different classification schemes

Abstract

The Chenab River has always offered a cradle for civilizations in Punjab province of Pakistan; however, in recent times, the quality of this river has been gradually degraded due to several point and non-point pollution sources being introduced in its water. The riverine water quality was evaluated to check the suitability of water for drinking, livestock and irrigation purposes. Water samples (n  54) were collected across the river, over a period of three years (2012-2014) and subjected to physicochemical analysis. Water quality index rating revealed that the water of River Chenab fell under the marginal category for drinking and livestock watering, due to the presence of heavy metals pollution above safe limits. Irrigation suitability parameters, such as the sodium absorption ratio (SAR), residual sodium carbonate (RSC), Na (%), Kelley's ratio (KR), magnesium hazard (MH) and the permeability index (PI) were measured, and most of the samples were within the safe limit. The piper classification of hydro-chemical parameters revealed that the alkaline-earth metals and strong acids exceed the alkali metals and weak acids, respectively. A Wilcox diagram indicated the alkali hazard was low while salinity hazard has an increasing trend. Spatiotemporal distribution of the pollutants highlighted minimal pollution until Qadirabad site (S4) which gradually keeps worsening at the downstream sites. Two factors of water quality deterioration were identified as pollution addition from the point and nonpoint sources, and diversion of the water through canals. It is inevitable to manage water quality of the Chenab River by reducing point sources pollution, through law enforcement.