Application of water quality index (WQI) and statistical techniques to assess water quality for drinking, irrigation, and industrial purposes of the Ghaghara River, India

Ghaghara river samples were analysed to determine their quality and fitness for household, agriculture, and industrial use. In Ghaghara River, the cations were present in order of Ca²⁺ > Mg²⁺ > Na^{+ >} K ^+, and anions were in order of HCO₃^– > SO₄²⁻ > Cl⁻ > NO₃^– > F⁻. Gibbs's diagram indicated that carbonate and silicate weathering significantly influence the Ghaghara River ion chemistry. Piper trilinear diagrams indicated that Ca²⁺+ Mg²⁺ exceeded the Na⁺+ K ⁺, and anions of weak acids dominated over the anions of strong acids, indicating Ca-HCO₃ type of water. Based on the WQI values, the water quality class varied from 'unsuitable for drinking' to 'excellent' quality, and the parameter of concern was pH and fluoride ion concentration as they exceeded their permissible limits in the post-monsoon season, thereby negatively affecting the WQI values to unsuitable category. The computed value of the agriculture indices, including the Sodium absorption ratio (SAR), Sodium percentage (Na %), Kelly ratio (KR), Permeability Index (PI) value, Magnesium absorption ratio (MAR), and Potential salinity (PS), indicated that water quality was suitable for agriculture use. The Langelier Saturation Index (LSI) values indicated that 39% of the collected samples were unsuitable due to scale formation problems. Ryznar Stability Index (RSI) values indicated that the water of the Ghaghara River is corrosive and unsuitable for industrial use.