Abstract:

This research aimed to emphasis Tigris river water quality and quantity variations at two sites: Qaber Al-Abid village downstream Mosul city and Dwezat village after its meeting with the Upper Zab river using factor analysis technique. Weekly samples were collected from the two sites along a year. Samples were tested for pH, electrical conductivity, total alkalinity, total hardness, calcium, magnesium, sodium, potassium, chloride, sulphate, nitrate, phosphate, dissolved oxygen, biochemical oxygen demand, suspended solids, total solids, total dissolved solids, in addition to the discharge of the river. The results of each site were analyzed statistically using factor analysis for each season and for the whole year. Factor analysis concentrated the measured water quality parameters and discharge into two to four factors for seasonal analysis, which represent (90.69%-100%) of the variation in water quality and quantity. On the other hand, five factors were extracted from the yearly data at Qaber Al-Abid site and six factors at Dwezat site.The results of factor analysis revealed that pH, conductivity and PO4- 3 is the highest contributor to the variation in water quality at the two sites. Organic pollution came in the second order in Qaber Al-Abid since it is location downstream of Mosul city, while the effect of Upper Zab made the discharge and sediment load (SS, TS and TDS) in the second order for the variation in Dwezat site.

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