Assessing drinking and irrigation water quality in a highly altered subtropical river in India using hydro-chemical indices

Abstract

River water pollution and the subsequent degradation of water quality for irrigation and drinking are reported worldwide, especially in tropical regions with excess population pressure. The present study intends to investigate irrigation and drinking water quality and assess their suitability in the subtropical Damodar River in India using hydrochemical indices during pre-monsoon (PRM), monsoon (MON), and post-monsoon (POM) periods. The water quality index (WQI) results reveal that the river's water is unsuitable for drinking, as 68.92% (52.95% in PRM, 86.54% in MON, and 66.88% in POM) of samples are found to be unfit for consumption in the temporal dimension. However, in the spatial dimension, the percentage of unsuitable water samples is primarily high near the village of Mujher Mana station, with 97.20% of samples (97.87% in PRM, 97.91% in MON, and 95.83% in POM) deemed unfit for drinking. This suggests the Damodar River water in MON and near the village of Mujher Mana needs treatment before drinking. The study's findings from the irrigation hazards indices and the local farmers' feedback indicate that the river water is suitable for irrigation use. Moreover, SAR, %Na, KR, and PS are high at Mujher Mana village, RSC at Raniganj downstream (Ds), PI at Barakar, and MAR at Durgapur upstream (Us) in terms of spatial extent. The ANOVA test indicates a significant variation in river water quality across different spatio-temporal dimensions in the study area. Water pollution is mainly attributed to the discharge of untreated industrial and urban effluents directly into rivers, without undergoing water treatment. Therefore, it is imperative to address the issue promptly to reinstate the river water quality.

Keywords: Damodar River; Drinking water; Irrigation hazards; Irrigation water quality; Spatio-temporal dimension; Water quality index.

Fig. 1

Study area with sampling stations, (a) Location of the DRB in the Eastern part of India, (b) Drainage network of the DRB with dams and barrages, (c) Water samples collection stations (Note: Sample locations from 1–11 are mentioned in Table 1 based on WBPCB data; Source: Fig. 1a–b were created by the authors using ArcGIS software- version 10.2 with the base layer from https://goto.arcgisonline.com/maps/World_Imagery; Fig. 1c was created by the authors based on European Space Agency (ESA) Sentinel-2 imagery- 45Q dated 01 January 2020 using https://livingatlas.arcgis.com/landcover/).

Fig. 2

Methodological flow chart adopted for the current study.

Fig. 3

Heatmap showing the correlation among the water quality parameters.

Fig. 4

Spatial and seasonal variation of the Damodar River water quality in terms of water quality index (WQI).

Fig. 5

Spatio-temporal distribution of sodicity hazard, (a) Sodium adsorption ratio (SAR) and (b) Percentage of sodium (%Na).

Fig. 6

Spatio-temporal distribution of (a) Kelly’s ratio (KR) and (b) Residual sodium carbonate (RSC) .

Fig. 7

Spatio-temporal distribution of (a) Permeability index (PI) and (b) Potential salinity (PS).

Fig. 8

Spatio-temporal distribution of magnesium adsorption ratio (MAR).

Fig. 9

Dynamics of the hydrochemical indices, (a) PCA component plot showing the association among the major indices controlling the hydrochemical evolution, (b) HCA showing the clustering of the water quality monitoring stations based on the nature of the water pollution.