The engineering schemes of the drainage systems in Iraq were designed to reduce Salinization problems on millions of hectares of agricultural lands and to reclaim lands for food production. The largest single project, the Main Outfall Drain "Third River", was first suggested by British engineers in 1951 as a means of removing highly saline irrigation drainage water from 1.5 million hectares of agricultural land between the Tigris and Euphrates in Central Iraq. Parts of the Main Drain were begun in 1950’s and more was completed in the 1960’s. The engineering work included the construction of the Main Drain between the Tigris and Euphrates starting from Main North Musayab Drain nearby Numaniya town and continues to West Shatra Drain (Figures 1and 15).
The later was discharged into Hour AL-Dalmaj. During the period 1970 to 1990 many companies had been involved in design and construction of the new watercourse of the Main Drain. But, the entire project was not completed until December 1993 by national engineering staff, (started on 25 may 1992 and finished on 7th Dec. 1993). The huge drain nearly 565 km in length, runs south from the end of Ishaki Drainnear Baghdad down the right side of Dalmaj Lake (it has in-and out-let link with the Dalmaj Lake). It continues down the right bank of the Shatt Al Gharraf and crosses the Euphrates via an inverted huge siphon beneath the riverbed just east of Nassiriya. It then skirts round the southwestern edge of Haur AL-Dalmaj, crosses the southeast corner of the Haur AL-Dalmaj (between raised embankments), and finally joins up with the Shatt Al Basra canal (man-made canal) which links the southeast corner of Haur AL-Dalmaj to the head of the Gulf via Khour Abdulla
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