This research aims to study the variation in water quality during four seasons of year 2012–2013 for Husseiniya stream. This stream is a branch of Euphrates river in Iraq. It passes through Karbala Governorate and serves as a source for different purposes in this region. Canadian Water Quality Index (CWQI) method was used to for the classification of this stream for domestic, irrigation, and aquatic uses during winter, spring, summer, and autumn seasons. This method is classified as relative subindex technique that depends on water quality standards; therefore, water quality parameters were adopted in this method, which were taken from different international standards. These parameters were temperature, turbidity, total dissolved solids, hydrogen power, total hardness, sulphates, chlorides, lead, cadmium, aluminium, and coliform bacteria. In CWQI method, the parameters of Husseiniya stream during the four seasons were compared with their optimum (desirable) and maximum (permissible) standards. It was found that there was clear variation in the classification of CWQI between the two ways. From other side, the seasonal behaviour for this stream was not clear during the study period for all parameters and for all uses.
Canadian Water Quality Index, Euphrates river, Husseiniya stream
 Hamedi, H., Mobarghai, N, Soufizadeh, S. & Rasouli, S.A., Survey of qualitative conditions and seasonal variation of the urban watercourses pollutants. J. Mater. Environ. Sci., 6(2), pp. 322–332, 2015.
 Al-Bahrani, H.S., Water quality deterioration of the Euphrates River before entering Iraqi lands. WIT Transactions on Ecology and the Environment, 182, pp. 3–14, 2014, ISSN 1743-3541 (on-line), doi: 10.2495/WP140011
 Mourhir, A., Ralitachidi, T. & Karim, M., River water quality index for Morocco fuzzy inference system. Environmental System Research, 3, p. 21, doi: 2014, doi: 10.1186/s40068-014-0021-y
 Al-Bahrani, H.S., Abdulrazzaq, K.A. & Saleh, S.A., Remote sensing for the irrigation water quality index of Euphrates River according to the Canadian method, Kufa Journal for Agriculture Sciences (3rd Scientific Conference for Agriculture College), Faculty of Agriculture, University of Kufa, Iraq, No. 5, pp. 49–69, 2013.
 Al-Bahrani, H.S., Abdul Razzaq, K.A. & Saleh, S.A., Remote sensing of water quality index for irrigation usability of Euphrates River. WIT Transactions on Ecology and the Environment, 164, pp. 55–66, 2012, ISSN 1743-3541 (on-line), doi: 10.2495/WP 120051
 Nikbakht, M., The effect assessment of Ahvaz No.1, 2 water treatment plant on Karoon water quality, M.Sc Thesis, Ahvaz IA University, 2004.
 Brown, R.M., McLelland, N.I., Deininger, R.A. & O’Connor, M.F., A water quality index – crashing the psychological barrier. Indicators of Environmental Quality, 1972. doi: http://dx.doi.org/10.1007/978-1-4684-1698-5_15
 Al Meini, A.J.K., A proposed index of water quality assessment for irrigation. Eng. & Tech. Journal, 28(22), pp. 1–18, 2010
 Bordalo, A.A., Teixeira, R. & Wiebe, W.J., A water quality index applied to an international shared river basin: the case of the Douro River. Environmental, 38, pp. 910–920, 2006. doi: http://dx.doi.org/10.1007/s00267-004-0037-6
 Dojlido, J., Raniszewski, J. & Woysie, C.J., Water quality applied to rivers in the Vistula river basin in Poland. Environmental Monitoring and Assessment, 33, pp. 33–42, 1994. doi: http://dx.doi.org/10.1007/bf00546659
 CCME, ‘Canadian water quality guidelines for the protection of aquatic life’, Canadian Council of Ministers of the environment, Manitoba Statuary Publications, Winnipeg, Canada, 2001.
 Al-Msuoodi, R.M., The water resources and their role on the agricultural production in Karbalaa Governorate, M.Sc. thesis, College of Science, University of Tikrit, Iraq, 2000.
 Al-Asady, H.K., Evaluation of irrigation network of Husseiniya Irrigation Project using geomatics techniques, M.Sc. Message, University of Technology, Iraq, 2014.
 Al-Hasnawi, H.A., An ecological study of the characteristic of drinking water in the city of Karbala, M.Sc., Faculty of Education for Girls, University of Kufa, Iraq, 2013.
 Zegel, W.C, Environmental Engineering Handbook Standards, CRC Press: Boca Raton, FL, 1999.
 FAO, Water quality for agriculture, Corporate Document Repository, FAO Irrigation and Drainage Papers, Job No.: T0234, Version: 29, ISSN: 0254-5284, Rome, Italy, 1994. http://www.fao.org/DOCREP/003/T0234E/T0234E00.HTM
 Warrnigton, P.D., Water quality criteria for microbiological indicators, Overview report, second edition, Environmental Protection Division, Ministry of Water, Land and Air Protection, Government of British Colombia, 2001.