Conny Waters – AncientPages.com – To what extent was the Zanj Rebellion responsible for the abandonment of the vast agricultural system in the Mesopotamian plain?
More than 7,000 long and abandoned earthen ridges cover a large area of over 800 km² of the Shatt al-Arab River near Basra in modern-day southern Iraq, marking the site of an extensive agricultural expansion in the past.
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The ridges of the Shaṭṭ al-ᶜArab floodplain were once massive features, which can still be seen today.
They form linear embankments, typically varying in length from approximately 400 to 1200 meters with a width of roughly 20 to 50 meters, in some cases reaching a height of 2 meters above the ground surface.
Most are laid out in parallel groups of similar dimensions, separated by 100–250m of flat land forming ‘blocks’, arranged around and demarcated by approximately orthogonal, relict canals.
It’s worth mentioning that even in earlier research, scientists made a significant discovery in the Eridu region of southern Mesopotamia, revealing a vast and well-preserved network of ancient irrigation canals.
The reconstructed irrigation canal network in context with the ancient Euphrates riverbed and the archaeological sites of the Eridu region. The base map is a Corona satellite image. Credit: Antiquity (2025). DOI: 10.15184/aqy.2025.19
Scholars have often suggested the ridges were created by the hard work of black slaves during the early Islamic period and the ‘Zanj rebellion’ from 869 to 883 AD.
The Zanj irrigation system in Basra taken during the fieldwork – an aerial view. Image credit: Durham University
An international team of scholars has now successfully established the first absolute chronology for the construction and use of agricultural ridges.
By using a sophisticated technique known as Optically Stimulated Luminescence (OSL) dating, they discovered that the area remained under cultivation between the 9th and 13th centuries.
This means that farming in the region successfully continued long after the slave rebellion had ended, and the uprising was not the sole cause of the system’s eventual abandonment.
See also:
Advanced Ancient Irrigation Network Discovered In Mesopotamia
The precise reasons behind the eventual abandonment of the farming system are still unclear.
However, several plausible hypotheses have been suggested. Among the most prominent theories is the impact of the Mongol invasions during the 13th century, which could have disrupted agricultural activities through widespread destruction and displacement of local populations.
Drone photograph looking west showing several linear ridge features within the study area. Sample site 2 is visible in the lower right-hand corner Image credit: authors.
Additionally, outbreaks of plague in the 14th century contributed to a sharp decline in population, thereby reducing labor availability essential for maintaining extensive farming operations.
CORONA satellite photograph of a typical area of ridge/earthwork features within the study area. Photograph number DS1035-1040DF019 captured 23 September 1966 (reproduced courtesy of the US Geological Survey.
Furthermore, climate change might have played a critical role by altering regional weather patterns and diminishing water resources necessary for sustainable agriculture.
The research team involved archaeologists from Durham, Radboud University in the Netherlands, the universities of al-Qadisiyah and Basra in Iraq, and Newcastle University.
Written by Conny Waters – AncientPages.com Staff Writer
