Abstract
As time progressed Iraq witnessed the transfer of power from the hands of the Umayyad dynasty in Syria to the Abbasids who established their State in Iraq. The following developments are detailed. During these days very little had happened with respect to land ownership, the question of Kharaj tax and even the agrarian relations between property owners, private farmers and the general peasantry. It may be assumed therefore, that at the start of the Abbasids period all the irrigation networks and infra structures were in good working conditions, and that all the required work force was available as the case had been in the Sassanid and Umayyad periods. The Abbasids may be credited for keeping the vast canal network of al-Sawad in good working conditions and they knew well that the major source of their revenue came from agriculture. Full description of the major canals, which had supplied the lands between the Tigris and Euphrates Rivers. The five main canals or arteries were all fed from the Euphrates and flowed in south easterly direction towards the Tigris where they poured; so naturally they were used for navigation between the two rivers in addition to irrigating all the lands here by vast networks of distributaries and branch canals and watercourses. The major part of these systems was inherited from the Sassanids and the Babylonians but they were kept in good working conditions all these centuries by good management and maintenance. These five major canals according to their sequence from upstream to downstream were called during the Islamic era as, Nahr al-Dujail off taking from the Euphrates at a short distance above Anbar, followed by Nahr Isa, Nahr Sarsar, Nahr al- Malik, and finally Nahr Kutha. The Euphrates River itself bifurcated at its downstream reach to two branches whereby its eastern branch irrigated in its turn a very extensive tract of land in the southern part of al- Sawad with a complex system of branches and tributaries. In following each of these canals great deal of details are given on the agriculture of the various districts and the towns they had served, their flourishing conditions and the prosperity they had enjoyed. Khalifah al- Mansour built the new capital of the Abbasid State, Baghdad at the heart of the Sawad region. There was a vast system of watercourses which served Baghdad and its environ that had originated mostly from Nahr Isa is also treated not failing at the same time to describe even the minute details of the various quarters of the city and the markets they had served, which were all based on the writings of contemporary Scholars. The long and deep trench called as the Shabour Trench, which had extended from Hit on the Euphrates down to nearly the Persian Gulf was given its share of detailing as it stood some waterworks, which was meant for defense rather than irrigation. This stream was carrying the major share of flow of the Euphrates during the Abbasids period before it ended indirectly into the Batyiha. It gave however very large branch from its right hand side before reaching the site of Babylon which was called Nahr Nil. This important canal flowed in southeasterly direction and poured at the end in the Tigris in the same fashion as the previous canals did and similarly spreading irrigation watercourses all the way down.
Keywords: Al- Sawad, Early Islamic Period, Baghdad Irrigation, Abbasids,
Iraq.