During the Holocene the Tigris-Euphrates river system, at the lower sector of the Mesopotamian Plain (Iraq), has been characterized by a complex morphodynamics in response to climate fluctuations and the extensive construction of artificial canals, dug since the first River Valley Civilizations. During the early Holocene, the sea-level rise caused a general and rapid northward shifting of the Persian Gulf shoreline, after which the general progradation of the Tigris and Euphrates delta system accounted for the shoreline regression up to the present position. Several studies focused on the Mesopotamian waterscape to identify, among others: i) the position of the shoreline during the maximum Holocene marine ingression (i.e., 6,000 yr BP); ii) the effect of the Tigris and Euphrates paleo-delta progradation during mid and late Holocene; iii) key features useful for distinguishing natural river channels from anthropogenic canals. In this context, this study aims to enhance the knowledge on the Holocene and historical morphodynamics of the Lower Mesopotamian waterscape and, in particular, on the paleo-hydrology of the ancient fluvial system. In particular, this study provides new geomorphological data useful for better comprehending the mechanisms and rates of the complex interactions between the dynamics of the natural waterscape and the distribution, shifting and abandonment of historical settlements and artificial canals. A remote sensing, multi-sensor approach has been adopted to identify the main geomorphological features and describe the associated morphogenetic processes. Optical and multi-spectral Landsat 8 satellite images have been processed for computing NDVI and Clay Index, as well as to extract Regions of Interest (ROIs). The spectral signatures of the ROIs have been extracted and compared among them. This analysis has been integrated with the investigation of the micro-topography obtained through the re-classification of different DEM sources: i) C-band interferometric SRTM and Sentinel-1 (ground resolution of 30 and 15 m); ii) optical ALOS datasets (ground resolution 30 m). Remote sensing multi-spectral analysis revealed useful to identify and delineate the geomorphological features associated to the Holocene progradation of the ancient Tigris and Euphrates delta system, past flood-events along the main distributary channels, surficial effects of channel migrations and marshes distribution. In particular, past flood-events have been identified by depositional and erosive landforms due to avulsion processes and the associated crevasse splays, other than by the position and planar pattern of artificial canals. In fact, these latter were essential for managing hydrological extreme events and, on the other hand, to take advantage from them (i.e. field irrigation system). Micro-topography analysis, integrated by the study of distribution of ancient settlements and the planar configuration of ancient distributary channels and artificial canals, allow to preliminary distinguish the geomorphological effects of the Holocene sea-level variations and the associated variations of the river morphodynamics.

Holocene and historical morphodynamics of the Lower Mesopotamian waterscape: a remote sensing, multi-sensor approach / Iacobucci, Giulia; Mazzanti, Paolo; Milli, Salvatore; Nadali, Davide; Troiani, Francesco; Zocchi, Marta; Forti, Luca. - (2019). (Intervento presentato al convegno 20th International Union for Quaternary Research (INQUA) Congress tenutosi a Dublino, Irlanda).

Holocene and historical morphodynamics of the Lower Mesopotamian waterscape: a remote sensing, multi-sensor approach

Giulia Iacobucci
;
Paolo Mazzanti;Salvatore Milli;Davide Nadali;Francesco Troiani;Marta Zocchi;FORTI, LUCA
2019

Abstract

During the Holocene the Tigris-Euphrates river system, at the lower sector of the Mesopotamian Plain (Iraq), has been characterized by a complex morphodynamics in response to climate fluctuations and the extensive construction of artificial canals, dug since the first River Valley Civilizations. During the early Holocene, the sea-level rise caused a general and rapid northward shifting of the Persian Gulf shoreline, after which the general progradation of the Tigris and Euphrates delta system accounted for the shoreline regression up to the present position. Several studies focused on the Mesopotamian waterscape to identify, among others: i) the position of the shoreline during the maximum Holocene marine ingression (i.e., 6,000 yr BP); ii) the effect of the Tigris and Euphrates paleo-delta progradation during mid and late Holocene; iii) key features useful for distinguishing natural river channels from anthropogenic canals. In this context, this study aims to enhance the knowledge on the Holocene and historical morphodynamics of the Lower Mesopotamian waterscape and, in particular, on the paleo-hydrology of the ancient fluvial system. In particular, this study provides new geomorphological data useful for better comprehending the mechanisms and rates of the complex interactions between the dynamics of the natural waterscape and the distribution, shifting and abandonment of historical settlements and artificial canals. A remote sensing, multi-sensor approach has been adopted to identify the main geomorphological features and describe the associated morphogenetic processes. Optical and multi-spectral Landsat 8 satellite images have been processed for computing NDVI and Clay Index, as well as to extract Regions of Interest (ROIs). The spectral signatures of the ROIs have been extracted and compared among them. This analysis has been integrated with the investigation of the micro-topography obtained through the re-classification of different DEM sources: i) C-band interferometric SRTM and Sentinel-1 (ground resolution of 30 and 15 m); ii) optical ALOS datasets (ground resolution 30 m). Remote sensing multi-spectral analysis revealed useful to identify and delineate the geomorphological features associated to the Holocene progradation of the ancient Tigris and Euphrates delta system, past flood-events along the main distributary channels, surficial effects of channel migrations and marshes distribution. In particular, past flood-events have been identified by depositional and erosive landforms due to avulsion processes and the associated crevasse splays, other than by the position and planar pattern of artificial canals. In fact, these latter were essential for managing hydrological extreme events and, on the other hand, to take advantage from them (i.e. field irrigation system). Micro-topography analysis, integrated by the study of distribution of ancient settlements and the planar configuration of ancient distributary channels and artificial canals, allow to preliminary distinguish the geomorphological effects of the Holocene sea-level variations and the associated variations of the river morphodynamics.
2019
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/1321099
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