Abstract
Water quality index (WQI) has been used as a geometric mean method to evaluate and classify 13 wells water, six of them are shallow wells and penetrate quaternary aquifer, the rest are deep wells and penetrate Injana aquifer in Debagh –Makhumar Plain in North East of Iraq. Result showed that Water quality index for drinking purpose range between 12.2 to 89.8% within poor to good class of drinking according to Bhargava classification, all shallow wells were classified within good class for drinking except well 13 which was classified as poor class. While deep wells were classified within poor class except the wells 2 and 4 which were classified within good and fair class , respectively.
Water quality index for irrigation purpose range between 51.6 to 93.2 % within fair to excellent class, all deep and shallow wells were classified within excellent and good class except the wells 6 and 7 which were classified within fair class for irrigation. Factor analysis (FA) was applied to ground water chemistry data and showed that 80.8% of the variance in the original data belong to the impact of salinity,total hardness,calcium,magnesium, sodium, chloride and sodium adsorbtion ratio SAR, these parameters control of ground water quality and contribution to water quality index degradation .
