A review of Holocene avulsions of the Tigris and Euphrates rivers and possible effects on the evolution of civilizations in lower Mesopotamia

Abstract

The role of avulsion in the evolution of civilization in lower Mesopotamia is widely recognized. Ancient settlements are closely associated with abandoned courses of the Euphrates and Tigris Rivers. This paper discusses avulsion history, controls of avulsions, their effects on civilization evolution from 7000 to 1000 yr B.P., and interactions between human activity and channel-network evolution based on previous archaeological and geomorphological surveys, analysis of cuneiform texts, maps, satellite photos, and limited geological data. Settlement distribution in ancient Mesopotamia is modeled in relation to avulsion styles, as well as channel and sedimentation patterns. Avulsion belts are suggested as places where urban settlements emerged and were sustained. Multiple channel networks and avulsion belts created large, naturally irrigated areas, fostering the efficient agriculture needed to sustain dense rural and urban settlements. After channel networks were abandoned during delta evolution, largescale canal construction was required to sustain settlements but still could not prevent their decline.

The Euphrates-Tigris-Karun river system: Provenance, recycling and dispersal of quartz-poor foreland-basin sediments in arid climate

“…Besides the relevant archeological implications (Lees and Falcon, 1952;Morozova, 2005;Wilkinson et al, 2015), monitoring the compositional variability of modern sediments in big-river systems such as the Euphrates-Tigris-Karun drainage basin, over 10 6 km 2 wide and ranking about twentieth on Earth, provides us with a key to understand the information stored in sedimentary archives, and to reconstruct the evolution of the Earth's surface from the recent to the less recent past. Previous mineralogical studies on recent Mesopotamian sediments include Philip (1968), Berry et al (1970), Ali (1976), and Al-Juboury and Al-Miamary (2009) and Awadh et al (2011).…”

The role of geoarchaeology in extending our perspective

“…River courses are also notoriously changeable, and have had their effect on cultures through time and around the world (e.g. Howard et al 2003;Morozova 2005;Adelsberger & Kidder 2007;Rapp & Jing).…”

“…Kraft et al). Morozova's (2005) work on the Tigris and Euphrates rivers provides a good example. Periodic avulsions of the river channels would have had negative effects on settlements along those channels, but Mesopotamian farmers were also able to use the floodplain and channel morphology to their own advantage, for gravity irrigation and for access to better drained soils that were less susceptible to flooding and salinization.…”

Assessing human impact on alluvial fan development: a multidisciplinary case-study from Lower Khuzestan (SW Iran)

“…Since ancient times, natural levee breaks and their associated crevasse-splays formed the ideal loci for irrigation, transforming levee breaks into outflow points for irrigation water [13,14,16]. The same principle is still being applied today across alluvial fan J3.…”

“…Due to the dry climate in the region, societies have always depended on the position of these rivers for their economic survival. Throughout the history of Mesopotamia, as well as Lower Khuzestan, there is evidence of human activities that influenced the natural avulsion processes in order to control the distribution of water across the plains [10,[12][13][14][15][16].…”