Water Quality Index Application to Evaluate the Ground Water Quality in Kalar City- Kurdistan Region- Iraq

Abstract

Abstract The study is aimed to identify and classify the quality of ground water in Kalar city- Kurdistan region- Iraq through a single number that achieves by water quality index (WQI). Weight arithmetic water quality index (WAWQI) was used to assess 14 physicochemical water parameters such as turbidity, pH, total dissolved solids (TDS), total hardness (TH), total alkaline (TA), electric conductivity (EC), dissolved oxygen (DO), sodium (Na+), calcium (Ca2+), magnesium (Mg2+), sulfate (SO4 2−), chloride (Cl−), nitrate (NO3 −) and potassium (K+). Ground water samples were taken from 5 stations in different locations in Kalar city during the period of March and April 2021. In addition, 20 samples were taken for 5 stations in total, 4 samples for each station, 2 samples in March and 2 in April, the interval period for taking samples was 2 weeks. Water quality indices of stations 1, 2, 3 are 53.10, 51.95 and 51.08 respectively, they are in poor quality range, thus the water quality of these station is moderately polluted, while water quality indices of stations 4 and 5 are 42.23 and 44.66 respectively, which are in good quality range. The study concluded that the ground water in kalar city is slightly to moderately polluted. Calcium and magnesium contaminants in Kalar ground water are high and must be decreased into safe range. TDS, TH, DO, pH and turbidity values are in allowable ranges in all 5 stations, but they are critical and need treatment to get an excellent water quality.