Supplying a medieval metropolis: water management and agriculture in the hinterland of early Islamic Basra

Abstract

Following its foundation in the 630s CE, medieval Basra rapidly expanded to became one of the most populous cities of southern Iraq and the wider Gulf region. At its foundation, the city’s surrounding environment appears to have been poorly suited to sustaining a large urban population. This paper examines the different ways in which the early Islamic population of Basra transformed the immediate environs of the city to improve the urban water supply and the agricultural potential of the city’s hinterland. In particular, this included the construction of substantial canals connecting Basra with sources of water such as the marshes to the north of the city and the Shaṭṭ al-cArab—the river which forms at the confluence of the Tigris and Euphrates and flows past Basra to the Gulf. The tidal influence of the Gulf causes the water level of the Shaṭṭ al-cArab to rise and fall daily and, by exploiting this characteristic, the medieval population of Basra could irrigate large swathes of land surrounding the city. Analysis of historic satellite imagery reveals possible evidence for the infrastructure that made this possible—including the remains of field systems bounded by, and interspersed with, canals as well as large raised linear ridge features which occur in tandem with relict canal systems. This paper critically assesses the evidence for the dating of these features, potential scenarios for how they functioned and their relationship to the medieval city of Basra.