Postdoc vacancy: Rivers of the Silk Roads

Rivers of the Silk Roads: how water shaped societies and empires in Central Asia  (Leverhulme Trust funded project)    36 month PDRA (£34,304 starting salary) with expertise in remote sensing and hydraulic modelling required from September 1^st, 2022 to work with Professor Mark Macklin (University of Lincoln, UK) and Dr Willem Toonen (Vrije Universiteit Amsterdam, Netherlands)     Project summary and PDRA role: The importance of Central Asia’s Silk Roads to world history is well known. But what is not understood is the role that rivers in the region played in the development of nomadic and urban societies, and empires, particularly irrigation-based agriculture but also as water-rich corridors for pastoralists and travellers. Rivers of the Silk Roads is a novel and ambitious interdisciplinary project which uses state-of-the-art dating, hydraulic modelling and satellite imaging techniques, combined with archaeological investigations of ancient canal systems, to provide the first multi-millennial length reconstructions of changing water resources and water hazards along Central Asia’s Silk Roads. The PDRA will facilitate process-based connections between short- and long-term hydroclimatic change and the dynamics of regional flood-irrigation networks in each study area. Site based reconstructions will be made of flood regime changes in order to infer water availability for irrigation. Combined with a functional analysis of irrigation-canal networks, based on remote sensing and field investigations, agricultural yield will be modelled. The PDRA, supervised by Professor Macklin and Dr Toonen, will undertake two work packages.   WP1. Remote sensing and mapping of irrigation infrastructure, palaeochannels and canals, alongside ancient settlement distribution. Using high-resolution, gridded dataset of Earth’s floodplains generated from Shuttle Radar Topography Mission, and declassified CORONA satellite images, the PDRA will map (GIS-aided visual interpretation) and then digitise canal networks and associated field systems. CORONA images (1960-1972; KH-4B) are easily accessible from the USGS EROS Archive, have high spatial resolution (1.8-2.7 m) and because these are amongst the earliest imagery available across Central Asia, they predate the considerable damage and loss of archaeological sites (including ancient canals and field systems) that has happened over the last 40 years as a result of agricultural and urban development. All data, including new and recorded archaeological sites, will be mapped and archived using ArcGIS with the intention of developing an open-access GIS that would be made available to researchers and heritage managers in both Central Asia and more widely. From these analyses the PDRA will establish the form and phases of irrigation infrastructure in each of the study areas, including quantitative information on canal system length and dimensions, as well as the total area of irrigated fields and how these developed and changed over time. WP2. Hydraulic modelling of canal systems to assess the likely population size they could sustain based on irrigation-supported agricultural yield, and how this may have changed over time. The cross sectional area and slopes of canals for each phase of irrigation development will be surveyed and, using an appropriate roughness value derived from Manning’s equation, their maximum flow carrying capacity calculated. To evaluate the performance of canal networks for different time periods, with respect the volume of flow and the areas of irrigated land that they could support, the PDRA will use the US Corps of Engineers Hydrologic Engineering Center’s (2009) HEC-GeoRAS model. Average spring and summer flows from the feeder river systems based on gauged, tree ring and palaeohydrological estimates (determined from the dimensions of feeder channels contemporary with the phase of irrigation being modelled will be numerically routed through the canal system to evaluate the performance of the canal network. This will include determining if the feeder canal was able to supply all of the secondary canals simultaneously or if it was necessary to create a schedule of rotating water delivery. The PDRA will use the United Nations FAO “CROPWAT” software, to calculate the amount of water to grow staple cereal crops and vegetables that require irrigation, and compare this with estimated flows in canal systems for each time period.   For further information please email Professor Mark Macklin (mmacklin@lincoln.ac.uk) or Dr Willem Toonen (w.h.j.toonen@vu.nl). The successful applicant should be available to start this post on September 1^st 2022, or very shortly after this date.