http://hdl.handle.net/2122/163 Sat, 18 May 2013 00:43:21 GMT 2013-05-18T00:43:21Z http://hdl.handle.net/2122/7423 Title: A Multidisciplinary GIS-Based Approach for Mapping Paleoriver Migration: A Case Study of the Serchio River (Lucca Alluvial Plain, Tuscany) Authors: Bisson, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia; Piccinini, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia; Zanchetta, G.; Dipartimento di Scienze della Terra, Università di Pisa, Pisa, Italy; Abstract: This paper presents a multidisciplinary study of river migration in alluvial plains. The selected case study is a sector of the Lucca alluvial plain (Tuscany, Central Italy) in which the Serchio River flows. Various types of data were collected, analyzed, and processed using a GIS. In particular, remote sensing imagery of different resolution (aerial orthophotos and satellite images) were processed to enhance buried fluvial features. Detected features were compared with data from stratigraphic investigations, archaeological surveys, geomorphological maps, and previous remote sensing studies. Traces of ancient channels were mapped and compiled in an interactive vector database listing the most important characteristics of each element. Two fluvial channel systems (here called primary and secondary) of differing size (e.g. length and width) were identified. Our analyses confirm the major features of the main paleochannels identified in previous works and enabled the discovery of smaller channels thanks to the higher resolution of the source data. These new traces suggest the existence of a secondary drainage network comprising minor channels of the Serchio River modified by human activity. These secondary paleotraces are possibly linked to channelling for land reclamation purposes beginning in the Roman period, when the alluvial plain was reorganized on the lines of Roman centuriation. Thu, 10 Nov 2011 23:00:00 GMT http://hdl.handle.net/2122/7423 2011-11-10T23:00:00Z http://hdl.handle.net/2122/7419 Title: A multidisciplinary approach to reveal palaeo-hydrographic features: the case study of Luna archaeological site surroundings Authors: Bisson, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia; Bini, M.; Dipartimento di Scienze della Terra, University of Pisa, Pisa, Italy Abstract: This article presents a multidisciplinary study implemented in Geographic Information System (GIS) environment to investigate the palaeo-hydrography in a sector of the Magra River alluvial plain (north-western Italy) where the famous ruins of the Roman colony of Luna (now Luni) are located. The approach proposed here combines the results obtained by different remote sensing images (satellite and airborne photos) with the data derived from historical cartography and recent field surveys. The traces are mapped and organised in two vector databases organised in linear or polygonal features consistent with fluvial elements (e.g. palaeo-channels, abandoned streams, etc.) and marshy/swamp areas, respectively. This database represents a useful starting point that can be implemented by further more detailed studies aimed to better understand the evolution of the landscape and the possible relationship with the story of the archaeological site of Luna about which many questions are still unresolved. Sat, 31 Dec 2011 23:00:00 GMT http://hdl.handle.net/2122/7419 2011-12-31T23:00:00Z http://hdl.handle.net/2122/6152 Title: Historical floods and a recent extreme rainfall event in the Murgia karstic environment (Southern Italy) Authors: Polemio, M.; CNR-IRPI Abstract: In karstic areas, the mean annual stream flow is low in terms of mean annual net rainfall percentage, and, in many cases, stream flow is so rare to be considered an exceptional independent of the peak flow value. Nevertheless, many types of flooding processes can be identified in karsts. We consider the recharge-related flooding of a bare karst, with a case study of a Mediterranean area dominated by semi-arid climate. In these cases floods are rare, short, and sudden but the effects are often very dramatic. Three types of analyses were used. The historical analysis focused on the series of past or historical flood events, which provided a means to define the flood recurrence period and damage levels, and the main steps of anthropogenic development expressed by the population number and needs. The hydrological analysis considered long time series of annual maximum short rainfalls, in order to assess the return period of high intensity rainfall that caused the studied flood event. The geomorphological analysis considered rainfall, the hydrogeological characteristics of outcropping rocks and soils and the geomorphological data of the drainage basin to calculate net rainfall and peak flow characteristics. We explored historical flood events for the study area, characterising the role of human effects on damages, and used a recent flood event to test our capability to estimate ephemeral river flow on the basis of rainfall measurements. The historical analysis of floods and damages highlighted four flood periods, distinguished on the basis of the recurrence period and the level of damages. It is clear that the lessons of past flood events are quickly forgotten. The hydro-geomorphological analyses showed the peculiarities of the 2005 flood event. The maximum rainfall return period for the 2005 event was due to exceptional three-hour cumulative rainfall. This study shows that we can estimate peak flow characteristics even when time series of river flows are not available, thereby allowing us to improve our capability to forecast the flooding effects of severe storms in karstic areas. Thu, 31 Dec 2009 23:00:00 GMT http://hdl.handle.net/2122/6152 2009-12-31T23:00:00Z