Irrigation is forever: A study of the post-destruction movement of water across the Ancient Site of Sri Ksetra, central Burma

Abstract

Sri Ksetra is a very large urban site created by the Pyu people, ca. fourth century AD, on the southern edge of the Dry Zone of Central Burma. Ancient irrigation works, discovered by Stargardt in 1985-1988 and first published in 1990, were essential to its urban development and, though rarely visible as surface features today, still profoundly affect the post-destruction settlements on the site and their rice harvests. This paper documents the sub-surface and surface movement of moisture across the site after the end of the monsoon season, i.e. in the period from September to February. It is based on the study of combined resources, including spaceborne multi-spectral and multi-temporal satellite imagery, aerial photographs and archaeological maps. It reveals how surface and sub-surface water still flows along the ancient irrigation channels and collection tanks of the site and demonstrates that an ancient system, which has been in an advanced state of sedimentation for over 1,000 years, still functions mainly at a subsurface level, creating differences in soil productivity and drainage today. The study explores the potential value of freely available imagery of medium resolution for archaeological research on other ancient landscapes embedded in modern ones where differences of wetness and vegetation are significant. Finally, these satellite images record the presence of ancient ritual ponds and associated burial terraces in the southern extramural area in a degree of detail that, surprisingly, compares well with the aerial photographs taken over 50 years ago when surface disturbance was at a lower level.