Development of a Water Quality Index Using Sparse Principal Component Analysis for the Tigris River in Iraq

Freshwater levels in the Tigris River significantly reduced during the last two decades due to global warming and geopolitics issues around Iraq. Thus, continuous and regular assessment for water resources became critically essential and this study was designed to evaluate the water quality of Tigris River and to develop a novel Water Quality Index (WQI). The raw water (untreated) and drinking water (treated) samples were collected from twelve stations. Twenty parameters were assessed for each sample based on the standard methods including physical properties of water such as total dissolved solids, suspended solids, temperature, turbidity, PH, color, conductivity and also, chemical species such as F-, Cl-, Na+, K+, Ca+2, Mg+2, Fe+3, Al+3, NH3, SO4-2, PO4-3, SiO2, NO2-, NO3-, Using the above data a novel WQI was created using sparse principal component analysis. This sparse principal component WQI successfully identified a small subset of important variables that contribute to water quality.