GNGTS 2014 - Atti del 33° Convegno Nazionale

GNGTS 2014 S essione 3.1 79 depression (up to 4-5 m of depth) close to the bridge piers, that is probably due to active erosion. We note that areas of prevailing erosion, such as the wide depression immediately N of the bridge, and the external flank of the meandering river towards N, are marked by high- reflectivity patterns, suggesting that this parameter could be useful to study erosional processes in such environments. Future Improvements. The geophysical instruments payload presently installed onboard of SWAP is not exhaustive of all possible geological processes that could be eventually analyzed in shallow-water areas. In fact, the possibility of installing onboard of SWAP other instruments, such as multibeam echosounders or electromagnetic devices (Ground-Penetrating Radars, Magnetometers, Resistivity-meters, etc.) could represent a dramatic improvement in data collection potential. The peculiar design of the hull is suitable for installing ADCP current- meters, that find a wide range of application in hydraulic and physical oceanographic studies. Furthermore, some basic chemical sensors, such as oxygen, nitrates, PH, etc., now available in small and light containers, could represent interesting payloads to carry out rapid assessment of the surface water quality. Conclusion. We presented some case studies of geophysical surveys carried out in different shallow-water environments using an Unmanned Surface Vehicle (USV). The possibility of carrying out such kind of surveys quickly, and at a fraction of the cost of conventional surveys, opens the use of these techniques to a wide range of users. Moreover, it allows planning repeated surveys that could give a time-variant perspective to the study of natural process in these rapidly evolving environments. Acknowledgments. Most figures were compiled using GMT software package (Wessel and Smith, 1991). Part of this work was supported by Consorzio Proambiente, Tecopoli dell’Emilia Romagna. References Barbieri M., 2003. Brevi note storico-geografiche sul Reno, in BARBIERI Magda (a cura di), Reno, campi e uomini, Rivista periodica della pianura , Anno I, n. 1, giugno-dicembre 2003, www.pianurareno.org  Barry, K.M., Cavers, D.A. and Kneale, C.W., 1975, Recommended standards for digital tape formats. ����������� Geophysics, 40 , 244-352. Bortoluzzi, G., Gasperini, L., Bellucci, L.G., Ligi, M., 2005. Ricerche Geofisiche nel Lago Trasimeno, ISMAR-CNR Bologna, Rapporto Tecnico N.97, Novembre 2005, Bologna, pp.49. Bondesan, M., Favero, V. and Vignals, M.J., 1995, New evidence on the evolution of the Po-delta coastal plain during the Holocene, Quaternary International , 29/30 , 105-110. Brizzi G., Gambini E., 2007. Di nuovo sulla battaglia del Trasimeno qualche ulteriore considerazione. Rivista storica dell’antichità, ISSN 0300-340X, Nº. 37, 77-100. Cattuto, C., Gregori L., 1993. Origine ed evoluzione del Lago Trasimeno. Conferenza Auditorium Urban i. 15 Marzo (Assessorato della cultura - Passignano S.T. Università degli Studi di Perugia). Dunlop, J.I., 1992, Measurement of acoustic attenuation in marine sediments by impedance tube, Jour. Acoust. Soc. Am. , 91 , 460–469. Gasperini L., 2005. Extremely Shallow-Water Morphobathymetric Surveys: The Valle Fattibello (Comacchio, Italy) Testcase. Marine Geophysical Researches , p.26:97-107, 2005. Gasperini L. and Stanghellini G., 2009 - SeisPrho: an interactive computer program for processing and interpretation of high-resolution seismic reflection profiles, Computers and Geosciences , 35,1497-1504. Gasperini L., 2009 Il rilievo Geofisico-Geologico del Lago Trasimeno (F. 310 Passignano sul Trasimeno) Mem. Descr. Carta Geol. d’It. LXXXVIII (2009), pp. 57 - 60 Haynes, R., Huws, D.G., Davis, A.M., Bennell, J.D., 1997, Geophysical sea-floor sensing in a carbonate sediment regime, Geo-Marine Letters , 17 , 253-259. McCann, C. and McCann, D.M., 1969, The attenuation of compressional waves in marine sediments, Geophysics, 34 , 882-892. McCann, C. and McCann, D.M., 1985, A theory of compressional wave attenuation in noncohesive sediments, Geophysics , 50 , 1311–1317. Moroni Lanfredini, A. 2003. Il neolitico antico sul lago Trasimeno : il sito di Panicarola (la Lucciola) : l’industria litica. in: Rassegna di archeologia. A, Preistorica e protostorica. Firenze : All’insegna del giglio, c2002- 20A (2003), p. [87]-118