CENAS COASTLINE EVOLUTION OF THE UPPER ADRIATIC SEA DUE TO SEA LEVEL RISE AND NATURAL AND ANTHROPOGENIC LAND SUBSIDENCE

Transcription

1 CENAS COASTLINE EVOLUTION OF THE UPPER ADRIATIC SEA DUE TO SEA LEVEL RISE AND NATURAL AND ANTHROPOGENIC LAND SUBSIDENCE

2 Water Science and Technology Library VOLUME 28 Editor-in-Chief V. P. Singh, Louisiana State University, Baton Rouge, U.S.A Editorial Advisory Board M. Anderson, Bristol, U.K. L. Bengtsson, Lund, Sweden S. Chandra, New Delhi, India M. Fiorentino, Potenza, Italy w. H. Hager, Zurich, Switzerland N. Harmancioglu, Izmir, Turkey U. C. Kothyari, Roorkee, India A. R. Rao, West Lafayette, Indiana, U.S.A. B. M. Sahni, Aurangabad, India D. Stephenson, Johannesburg, South Africa The titles published in this series are listed at the end of this volume.

3 CENAS COASTLINE EVOLUTION OF THE UPPER ADRIATIC SEA DUE TO SEA LEVEL RISE AND NATURAL AND ANTHROPOGENIC LAND SUBSIDENCE edited by GIUSEPPE GAMBOLATI Department of Mathematical Methods and Models for Scienti.fic Applications (DMMMSA), University of Padova, ltaly SPRINGER-SCIENCE+BUSINESS MEDIA, B.V.

4 A C.I.P. Catalogue record for this book is available from the Library of Congress. ISBN ISBN (ebook) DOI / Front cover: Digital Elevation Model of the Upper Adriatic Sea basin. The red profile shows the maximal extent of the potentially ftooded area in the year 2100 due to meteo-marine storm with a 100 year return period. Internet site: Printed on acid-free paper AU Rights Reserved 1998 Springer Science+Business Media Dordrecht Originally published by Kluwer Academic Publishers in 1998 Softcover reprint of the hardcover 1 st edition 1998 No part of the material protected by this copyright notice niay be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without written permission from the copyright owner

5 TABLE OF CONTENTS Foreword xi 1 Coastal Evolution of the Upper Adriatic Sea due to Sea Level Rise and Natural and Anthropic Land Subsidence G. Gambolati, G. Giunta, M. Putti, P. Teatini, L. Tomasi, L Betti, M. Morelli, J. Berlamont, K. De Backer, C. Decouttere, J. Monbaliu, C.S. Yu, L Br ker, E.D. Christensen, B. Elfrink, A. Dante, M. Gonella Introduction Description of the Study Area Macroscale area Local scale areas Predicted Sea Level Rise due to Global Change Numerical Simulation of Processes Controlling the Coastal Morphodynamics Natural land subsidence Anthropic land subsidence Tides and Storm Surges Wave climate and storm waves Sediment transport Local scale morphodynamics along the Romagna coast Macro- and Local Scale Littoral Dynamics and Risk Analysis Conclusion 33 References Prediction of Mean Sea Level Rise in the Upper Adriatic Sea L Betti, M. Morelli Introduction Mean Sea Level Changes Causes of eustatic mean sea level changes Causes of absolute land elevation changes Mean sea level in the past Mean sea level in the next 100 years Sea Level Fluctuations v

6 2.3.1 Greenhouse effect and storm surges. 52 References Collection and analysis of historical data on shoreline evolution at the sites of Ravenna, Cesenatico and Rimini M. Morelli Introduction Sea Works Transverse works Works to contrast erosion Works to defend against high water The Evolution of the Beach The Rimini beach south of the gat The Rimini beach north of the gat The Cesenatico beach north of the gat The beach of Lido di Dante - mouth of Fiumi Uniti river - Lido Adriano (Ravenna) 72 References Numerical Modeling of Natural Land Subsidence over Sedimentary Basins Undergoing Large Compaction G. Gambolati, G. Giunta, P. Teatini Introduction Governing Equations Numerical solution: Lagrangian approach Numerical solution: Eulerian approach Analysis of the total stress variation during compaction with zero sedimentation rate Preliminary results from the non-linear compaction-sedimentation model Conclusions 100 References Numerical Analysis of Land Subsidence due to Natural Compaction of the Upper Adriatic Sea Basin G. Gambolati, P. Teatini Introduction Geological Setting of the Upper Adriatic Sea Basin Constitutive Soil Model for the Upper Adriatic Sea Basin Average Depositional Rates During Middle-Upper Pleistocene and Holocene Records of Natural Land Subsidence Numerical Analysis of Upper Adriatic Sea Basin Compaction Conclusion 127 References vi

7 6 Simulation of Land Subsidence Due to Gas Production at Ravenna Coastline P. Teatini, G. Gambolati, L. Tomasi, M. Putti Introduction Basic Model Formulation Implementation of the Nonlinear Reservoir Model Compressibility vs Effective Intergranular Stress for the Sediments of the Upper Adriatic Sea Basin Angela Angelina Gas Field Prediction of Land Subsidence over Angela Angelina Gas Field Conclusions 148 References Prediction of Land Subsidence Due to Groundwater Withdrawal along the Emilia-Romagna Coast M. Gonella, G. Gambolati, G. Giunta, M. Putti, P. Teatini Introduction Subsidence of the Romagna Coastline Hydrological Model of the Romagna Area Systeme Hydrologique Europeen The study area Hydrogeologic conceptualization Boundary conditions for the different model components Model calibration Simulation of withdrawal scenarios Land Subsidence Model Stratigraphic schematization of the application sites The one-dimensional subsidence model Model results Conclusions 166 References Wave refraction in the Upper Adriatic Sea C. Decouttere, K. De Backer, J. Monbaliu, J. Berlamont Introduction The Adriatic Sea Wave Climate The Model Ray tracing principle Model input Bora and Scirocco waves in the Adriatic Sea Model Results General aspects Accuracy considerations Different local sites Conclusions vii

8 References Storm Wave Simulation in the Adriatic Sea C. Decouttere, K. De Backer, J. Monbaliu, J. Berlamont 9.1 Introduction Storm Wave Information Selected Storms...., Storm 1, a Scirocco Return period and scaling factor 9.4 The WAM Model Introduction Spectral description of waves The energy balance equation Numerical scheme Wind waves and swell The input and output Adriatic Sea Implementation of the WAM Model Bathymetry Wind data Model parameters Results of the WAM runs Wave set-up estimation. 9.6 Future situation: year 2050 and Conclusions References Storm Surge Simulations in the Adriatic Sea C.S. Yu, C. Decouttere, J. Berlamont 10.1 Storm Surges Prediction Nature of Storm Surges in the Adriatic Sea 10.3 Scope of the CENAS Study 10.4 Mathematical Formulation Meteorological Forcing General Using pressure information only Using pressure and wind information Open boundary condition Simulation of Tides in the Adriatic Sea Simulation of Storm Surges in the Adriatic Sea Historic storms Calibration run : Storm Simulation of other storms 10.9 Scenarios Future storms Future bathymetry with future storms viii

9 1O.lOConclusions References Coastal Morphodynamics in Subsiding Areas B. Elfrink, E.D. Christensen, 1. Brf1ker 11.1 Introduction The Coastal Sediment Balance Longshore sediment transport On/offshore sediment transport Fluvial sediment input Human interventions Subsidence and sea level rise 11.3 Morphological Baseline Study Introduction Site 1: Ravenna Site 2 : Rimini Site 3 : Cesenatico 11.4 Coastline Evolution Introduction Future subsidence rates Ravenna Rimini Cesenatico Summary and Conclusions. References Local Morphological Evolution of the Coast in the Upper Adriatic Sea. Design and Management Strategies to Control Coastal Erosion B. Elfrink, E.D. Christensen, 1. Brf1ker, M. Gonella, M. Morelli Introduction Local Processes Near Offshore Breakwaters Description of the phenomena Coastal Evolution: Observed and Simulated Historical coastline changes north of the Rimini gat Estimation of sediment accumulation behind offshore breakwaters at Ravenna The Different Role of the Various Factors Contributing to the Shoreline Evolution and to the Risk of Coastal Lowland Flooding Evolution of the shoreline Flood risk analysis of the coastal lowlands Territory Management Strategies Objectives Instruments Coastal Defences for Beach Protection. Objectives and Strategies. 280 ix

10 Managing current defences New defence works Fields of application of numerical models The need for monitoring. References Geographic Information System (GIS) and Data Management and Retrieval System (DMRS) in the CENAS Project A. Dante, M. Gonella, P. Teatini, L. Tomasi Introduction The GIS component of the CENAS Project The Geographic Information System "GRASS" Data sources Topographical data and DEM construction Land use models Application of GIS to simulation results The DMRS component of the CENAS project The DMS component The DRS component. 304 References Flood Risk Analysis in the Upper Adriatic Sea due to Storm Surge, Tide, Waves, and Natural and Anthropic Land Subsidence M. Gonella, P. Teatini, L. Tomasi, G. Gambolati Introduction Macro Scale Littoral Dynamics and Risk Analysis "Potential" macro scale littoral dynamics Macro scale risk analysis of the "potentially" flooded areas Local Scale Analysis Flooded lowlands at the local scale Local scale inundation risk Conclusion 322 References Author Index 325 List of Contributors 326 Color Plates 328 x

11 FOREWORD The Upper Adriatic Sea basin comprises a very precarious coastal environment subject to continuous changes which prove appreciable not only over the geological scale but also in historical and modern times. According to some Authors the Venice Lagoon was formed years ago, and other lagoons (e.g. the Grado Lagoon in the northernmost part of the Adriatic) are even more recent. In addition to lagoons, the Upper Adriatic coastal area includes salt and fresh-water marshes and reclaimed land separated by several watercourses originating from the Alpine and Apennine ranges with a ground elevation not exceeding in many places 2 m above the mean sea l.evel (msl). A significant fraction of this lowland is already now below msl because of natural and anthropogenic land subsidence, land reclamation and sea level rise occurred over the last century. Natural land subsidence is still under way as a result of deep downward tectonic movement and consolidation of soils deposited in the most recent time. Anthropogenic subsidence is primarily due to groundwater pumping for agricultural, industrial, civil, and tourist use, and to gas withdrawal from a large number of gas fields scattered through the Upper Adriatic basin, and may still continue, although at a reduced rate, in the years to come. At the same time msl is expected to rise in the next century due to global climate change, mainly because of the greenhouse effect. Moreover, dangerous floods occur occasionally along the Upper Adriatic coastline. The well known Venice flooding on November 4, 1966 with 1.94 m above msl will remain an unforgettable event in the memory of many for a long time. The risk of inundation from the Upper Adriatic Sea is higher than in the historical past due to the combined effect of both sea level rise and land subsidence. Another important factor influencing the shore morphology is the sediment inflow from the several watercourses which flow into the Upper Adriatic Sea. The major river is the Po river with its pronounced and cuspate delta. In modern times channeling, diverting, banking and stream bed mining have prevented the sediments of the Po and other major rivers from reaching the sea, thus inducing a decreased beach nourishment and a growing danger for beach erosion. After World War II attempts have been made to protect the shoreline by the construction of fixed structures such as seawalls, jetties, groins, and breakwaters, and this adds to the complexity and the precariousness of a coastal environment which is highly sensitive to even minor modifications of the controlling factors. The objectives of the CENAS project are manyfold. The first objective is to identify, understand, and analyze the major processes which impact on the Upper Xl

12 Adriatic littoral morphodynamics. These include the expected mean sea level rise due to global climate change, the natural and anthropogenic land subsidence, the flooding caused by severe meteo-marine events, and the coastal sediment transport following the several actions undertaken by man during the last 50 years. The second objective is to collect, analyze, process, organize, and manage the extremely large quantity of non-homogeneous data needed to carry out the project. The necessary information has been provided by a number of institutions, which are all here gratefully acknowledged, including the National Research Council, the National Geological Survey,. AGIP Spa, the "Servizio Idrografico della Marina Militare", the "Servizio Idrografico e Mareografico N azionale", the Minister of Environment, the European Space Agency, Telespazio, Soyuz, ISPRA, ENEL, the "Magistrato alle Acque di Venezia", the "Consorzio Venezia Nuova", the "Romagna Acque Spa", the coastal Municipalities, and the Italian University. This huge amount of information is organized and handled by a Geographic Information System (GIS) with the generation of a DMRS (Data Management and Retrieval System). In particular a DEM (Digital Elevation Model) has been generated which describes the entire Upper Adriatic basin and the neighbouring land with a 200x200 m grid resolution, and an even smaller resolution over the coastal areas south of the Po river delta where a morphodynamical detailed study is performed. The third objective is to develop, calibrate and apply a set of ad hoc numerical models to address all the above mentioned processes and events over the area of interest. Finally, the last, and perhaps most important, project objective is to simulate and predict through an integrated modeling approach based on the models mentioned earlier the expected morphodynamical evolution of the Upper Adriatic coastal profile in the next century at both the macro and the local scale around the cities of Ravenna, Cesenatico and Rimini, and to assess the risk and the extent of the low lying coastal areas which may be potentially flooded during exceptionally severe storms. The CENAS study has required a huge effort in the organization of the available data into the GIS, the development, solution and calibration of the various phenomenological models, and the integration of the corresponding assumptions and results into a coherent framework for a most reliable prediction of the Upper Adriatic coastal morpho dynamics in the years to come. If this effort proves to be succesful, as we all sincerely hope, many will have contributed to this success. In the first place the University of Padova, Department of Mathematical Methods and Models for Scientific Applications (DMMMSA), for supporting the burden of the project coordination and the organization of the in-house printing of this final conclusive book. Next the project partners ARPA (formerly Idroser) Agenzia from Bologna, the Catholic University of Leuven, Belgium, the Danish Hydraulic Institute, Denmark, and MED Ingegneria from Ferrara. I would also like to express my most grateful thanks to AGIP Spa for providing a financial support for the completion of the local morphodynamical analyses and making available much of its geological and geophysical database along with the production programme over the Angela-Angelina gas field. Finally a special acknowledgement is to be made to the Municipality of Ravenna, Geological Service, for its active collaboration, xu

13 continuous support and inexhaustible encouragement which have contributed to the succesful development and completion of the CENAS project. Giuseppe Gambolati CENAS Project Coordinator xiii