process has not escaped the attention of cuneiform scholars and Edzard, drawing on
historical records that described a catastrophic shift in the bed of the Euphrates near
Mussaiyib in AD 1820 , has suggested that similar shifts could have dispersed those
ancient populations whom the Old Babylonian kings say they returned to their
settlements (Edzard 1957 : 117 ; also Potts 1997 , note 6 ). Also, a statement by Sin-
iddinam, king of Larsa, (c. 1849 – 1843 BC) may refer to an earlier avulsion:In order to provide sweet water for the cities of my country... [An and Enlil]
commissioned me to restore it [to its original bed].
(Frayne 1990 : 158 – 160 ; Steinkeller 2001 )WetlandsAlthough today much of southern Mesopotamia appears to be alluvial desert, arid salt
flats and belts of sand dunes, that indispensible guide to twentieth-century Iraq, The
Geographical Handbook,states: ‘In striking contrast to conditions on the Syrian desert,
the alluvial lands of southern Mesopotamia suffer from a surfeit of water’ (Naval
Intelligence Division 1944 : 189 ). In fact, marshes and wetlands were probably much
more significant during the Ubaid and the development of early states (Pournelle
2007 ). That wetlands were important during the period of Eridu is suggested by
Wright, who points out that the marshes provided a significant resource for the Ubaid
inhabitants (Wright 1981 : 323 ) and Postgate who described the marshes as ‘teeming with
life’ (Postgate 1994 : 158 ). The role of wetlands in the development of the prehistoric
communities was emphasised by Oates ( 1960 ) and more recently by Pournelle who
suggests that the earlier phases of Ubaid settlement were closely tied into a wetland
environment and many sites occurred on drier ‘turtle backs’ in the form of relict
Pleistocene islands (Pournelle 2003 , 2007 ).
Although wetlands evidently formed an important source of resources during the
phases of Ubaid settlement, the analysis of charred plant remains from Tell Oueli
demonstrate that cereals were also irrigated (Huot 1989 : 26 ; Neef 1989 ), but it is
difficult to say which was more important to the Ubaid economy. However, by the
third millennium BC, Sumer had become an important area of cereal production
(Winter 2007 : 120 ), and irrigated cultivation probably gained ground over the use of
wetlands. This may be because, although marshlands provide a wealth of resources in
terms of reeds, building materials, fish and molluscs, their over-exploitation can result
in their depletion, whereas irrigation and cereal agriculture enabled the economic base
of the growing Sumerian civilisation to be enlarged. This process of ‘positive feedback’
would have enabled the economy to grow further, as discussed below. It is even
apparent that during the third millennium BCwetlands were drained, as in the case of
the Ur III king Ur-Nammu, who is recorded as draining marshes estimated to cover 1
shargal(SHAR 2 .GAL, perhaps 233 sq km; Civil 1994 : 112 ).
The flood cycle
Critical to the agricultural economy was the annual flood cycle, which is poorly
synchronised with the needs of cultivators. In contrast to the Nile, whose monsoon-
driven annual flood well matches the needs of irrigation, the annual flood of both the–– Tony J. Wilkinson ––