Spatial Pattern of Total Dissolved Solids (TDS) Monthly Distribution in Shatt al-Arab River Water: Data Analysis for the Period (2015 – 2025)

Abstract

Objective: The present study aims to monitor and analyze the spatial pattern of Total Dissolved Solids (TDS) monthly and seasonal concentration distribution in the Shatt al-Arab River using government data from six monitoring stations. It calculates spatial variation rates between consecutive stations to identify critical months —when salinity levels peak—and moderate months, during which freshwater inflows successfully push the salt wedge southward or dilute TDS concentrations in the river water.

Method: This study employed a descriptive-analytical approach to the phenomenon of salt pollution, combined with quantitative and statistical methods, such as Percentage of Change method. The aim was to analyze raw data, derive rates and percentages of monthly spatial variations in TDS levels within the Shatt al-Arab River, interpret the causes of these variations.

Result: The findings showed a distinct hydro-chemical variation: upstream monitoring stations record relatively high salinity levels during the winter and spring months—due to restricted freshwater supplies and soil leaching—followed by a decline in summer resulting from compensatory water releases. Conversely, downstream stations exhibit a sharp upward trend peaking in months of summer and autumn, driven by reduced freshwater hydraulic pressure and the intrusion of the saline wedge from the Arabian Gulf.

Conclusion: TDS concentrations exhibit an irregular pattern throughout the year; however, they rise over time from May to December and increase spatially towards the south—approaching the estuary and marine waters—peaking at the Saihan station on the channel.