Study of Changes in Salt Concentrations of Main Outfall Drain system within Dhi Qar Governorate According to variables were occurred in 2022 ing to variables were occurred in 2022

Abstract

       Dhi Qar Governorate is considered the main confluence area for the drainage within Main Outfall drain system which are the East Gharraf drain, the Eastern Euphrates drain, the Greater Gharraf drain (Dutch drain), and the Western Euphrates drain (to be implemented in the future) besides the emergency escape. Main Outfall drain system in Dhi Qar is affected by the fluctuation in salt concentrations, by changes in the streamflow from Dalmaj Lake that is located at Wasit Governorate. Furthermore, it is affected by changes in the streamflow and salt concentrations of the main drains mentioned earlier. The current study aims to highlight the improvement of salt concentrations in recent years after converting Al-Nagara drain into one of the main subsidiary drains (the eastern Euphrates drain) which in turn flows into Main Outfall drain at km 186 in mid-August 2022 that helped reducing salt concentrations in the water pumped through Main Outfall drain’s pumping station towards parts of the western Hamar Marsh via a Khamisiya Canal. The current study included follow-up, monitoring, modeling and examination of water samples for a duration of one year for confirmed sites in Main Outfall drain system within Dhi Qar Governorate in which were the results showed that the concentrations of Total Dissolved Solids (TDS) improved significantly reaching the highest percentage of decrease 48 % in Km 168. This was when comparing the concentration values in the month of March for both of 2022 and 2023. Regarding the other months it is varied at a rate of 20%.