] Radiocarbon-dated fluvial deposits of old channel belts in lower Sindh indicate that aggradation on the megaridge was minimal during the late Holocene. This relative stability of the late Holocene landscape suggests that the abandoned Khaipur and maybe the Western Nara courses are likely older than ∼2700 years and secondary in importance in historical times (Giosan et al., 2012). The complex processes occurring along the Holocene Indus must, as well, have occurred high throughput screening in the context of environmental and climate variability. Pollen studies

from a core recovered from the Arabian Sea off the Makran Coast (24°509 N, 65°559 E; 695 m depth) show an end of more humid conditions, linked to a weakening of the monsoon, between 4700 and 4200 BP (Ivory and Lézine, http://www.selleckchem.com/products/BIBW2992.html 2009). From tree ring analysis, Ahmed and Cook (2011) conclude, as regards to current water supply along the Indus: “Perhaps the most worrying feature in the streamflow reconstruction is the occurrence of a pronounced and prolonged 112 year low-flow period from AD 1572 to 1683 (median: 3404 m3/s) and a shorter but much drier 27 year period from AD 1637 to 1663 (median: 3292 m3/s). The former is ∼7% below and the latter ∼10% below the median of the observed discharge record”. These initial

inferences and numerical estimates form a useful Holocene context to the larger changes of the Anthropocene; they constitute the “natural” environmental variability on top of which the human-driven changes are occurring. The Indus River presently feeds the world’s largest irrigation system (Fahlbusch et al., 2004). The Pakistan irrigation system is comprised of 3 major storage reservoirs, 19 barrages, and 43 major canals with a total conveyance length of 57,000 km. There are 89,000 watercourses with a running length of more than 1.65 million km (Inam et al., 2007). Major modifications to natural flows started as early as 1762 when the Phuram River at Mora was dammed as an act of aggression by Ghulam Shah Kalora to destroy crop production in

the Rann of Kachchh. The Mora Bund apparently still permitted seasonal flow of the river and additional Gefitinib mw dams were constructed downstream until in 1783, when the Aly Bundar dam successfully closed the southward egress of the eastern Nara to the sea at Lakput. River traffic between 1762 and 1826 was undertaken by barges between the dams until a flood destroyed all the dams in 1826, including the natural Allah Bund (a reverse fault scarp ridge) associated with the 1819 earthquake (Burnes, 1828). Development of the modern system began in 1859 when the Eastern Nara Canal, from Sukkur to the Eastern Nara River, changed the Eastern Nara from an overflow channel into a perennial branch of the Indus. The human footprint includes: 1. Construction of artificial levees to protect agricultural lands from inundation by floodwaters of the Indus, which started in 1869 near Sukkur (Asianics Agro-Dev 2000).