Application GIS Software to Determine the Distribution of T.D.S. Concentrations Along the Tigris River

Tigris River is a major source to supply water for a big part of Iraq. Lately, Iraq has experienced water shortage problems such as variability in climate and the building of huge dams in the upstream countries (Turkey and Iran). In this work, the total dissolved salts (T.D.S.) were measured at fourteen sites on the Tigris River in two periods of the year 2014. The first period consisted of six rainy-months (April–September) and the second period covered non-rainy-months (October-March). Interpolation technique of inverse-distance-weighting (I.D.W.) in ArcGIS was applied to create the prediction maps of the river for (T.D.S.) concentration in both periods. The findings revealed that the (T.D.S.) levels continued to the last site in Al-Qurnah-city (Basrah) from the first site in Fish-Khabur-city (S-1). In the first period, the (T.D.S.) levels at fourteen selected sites were over the levels in the second period. According to World-Health-Organization (2003), the (T.D.S.) concentration on the Tigris River in both periods in 2014 was graded into five classes, then, the prediction maps of the (T.D.S.) classifications were created.