Estimate Raw Water Salinity for the Tigris River for a Long Time Using a Mathematical Model

Abstract

The measurement data of the raw water quality of Tigris River were statistically analyzed to measure the salinity value in relation to the selected raw water quality parameters. The analyzed data were collected from five water treatment plants (WTPs) assembled alongside of the Tigris River in Baghdad: Al-Karkh, Al-Karama, Al-Qadisiya, Al-Dora, and Al-Wihda for the period from 2015 to 2021. The selected parameters are total dissolved solid (TDS), electrical conductivity (EC), pH and temperature. The main objective of this research is to predicate a mathematical model using SPSS software to calculate the value of salinity along the river, in addition, the effect of electrical conductivity on the salinity value was estimated. Multiple linear regression (MLR) and artificial neural network (ANN) models were used to estimate the mathematical models for calculating water salinity value in Tigris River and to present the highest effective parameter that effect on water salinity. In general, the results showed an increase in the water salinity level downstream of the Tigris River towards the south of Baghdad and the EC is the most significant effect on water salinity, and MLR and ANN analyses present a good indication of the mathematical models with highest coefficient of correlation (R2) as (0.999 and 0.998), respectively. In addition, the regression equations proved good performance in predicting the salinity value with error percentage less than 10% for all WTPs.