Is anthropogenic land subsidence a possible driver of riverine flood-hazard dynamics? A case study in Ravenna, Italy

ABSTRACT We investigate possible changes in flood hazard over a 77-km2 area around the city of Ravenna. The subsidence rate in the area, naturally a few mm year−1, increased dramatically after World War II because of groundwater and natural gas extraction, exceeding 110 mm year−1 and resulting in cumulative drops larger than 1.5 m. The Montone–Ronco river system flows in the southern portion of the area, which is protected against frequent flooding by levees. We performed two-dimensional simulations of inundation events associated with levee breaching by considering four different terrain configurations: current topography and a reconstruction of ground elevations before anthropogenic land subsidence, both neglecting and representing the main linear infrastructures (e.g. roads, artificial channels). Results show that flood-hazard changes due to anthropogenic land subsidence (e.g. significant changes in computed water depth and velocity) are observed over less than 10% of the study area and are definitely less important than those resulting from construction of the linear infrastructures.

[1]  Giovanni Martinelli,et al.  Subsidence rates in the Po Plain, northern Italy: the relative impact of natural and anthropogenic causation , 2002 .

[2]  J. Albertson,et al.  Evidence of an emerging levee failure mechanism causing disastrous floods in Italy , 2015 .

[3]  Robert L. Barkau,et al.  UNET: One-Dimensional Unsteady Flow Through a Full Network of Open Channels. User's Manual, , 1996 .

[4]  P. Bates,et al.  Comparing the performance of a 2‐D finite element and a 2‐D finite volume model of floodplain inundation using airborne SAR imagery , 2007 .

[5]  D. Zanchettin,et al.  Po River discharges: a preliminary analysis of a 200-year time series , 2008 .

[6]  A. Brath,et al.  Analysis of the effects of levee heightening on flood propagation: example of the River Po, Italy , 2009 .

[7]  Roger Alexander Falconer,et al.  Coupling surface and subsurface flows in a depth averaged flood wave model , 2007 .

[8]  D. Guha-Sapir,et al.  EM-DAT: The CRED/OFDA International Disaster Database , 2016 .

[9]  Renata Archetti,et al.  A coupled wave–3-D hydrodynamics model of the Taranto Sea (Italy): amultiple-nesting approach , 2016 .

[10]  F. Siringan,et al.  Global sea-level rise is recognised, but flooding from anthropogenic land subsidence is ignored around northern Manila Bay, Philippines. , 2006, Disasters.

[11]  M. Kearney,et al.  Sea-Level Rise Tipping Point of Delta Survival , 2017, Journal of Coastal Research.

[12]  A. Domeneghetti.  Effects of minor drainage networks on flood hazard evaluation , 2014 .

[13]  N. Phien-Wej,et al.  Land subsidence in Bangkok, Thailand , 2006 .

[14]  Francesca Carisi,et al.  Evolution of flood risk over large areas: Quantitative assessment for the Po river , 2015 .

[15]  P. Bubeck,et al.  Changes in future flood risk due to climate and development in a Dutch polder area , 2010 .

[16]  G. Gambolati,et al.  A century of land subsidence in Ravenna, Italy , 2005 .

[17]  A. Brath,et al.  Floodplain management strategies for flood attenuation in the river Po , 2011 .

[18]  B. Gouldby,et al.  Hydraulic model evaluation for large‐scale flood risk assessments , 2013 .

[19]  M. Hipsey,et al.  “Panta Rhei—Everything Flows”: Change in hydrology and society—The IAHS Scientific Decade 2013–2022 , 2013 .

[20]  T. Sturm,et al.  Open Channel Hydraulics , 2001 .

[21]  K. Hasan,et al.  A study on the development of subsidence due to the extraction of 1203 slice with its associated factors around Barapukuria underground coal mining industrial area, Dinajpur, Bangladesh , 2014, Environmental Earth Sciences.

[22]  G. Di Baldassarre,et al.  Towards understanding the dynamic behaviour of floodplains as human-water systems , 2013 .

[23]  Demetris Koutsoyiannis,et al.  Hydrology and change , 2013 .

[24]  Jie Yin,et al.  Modelling the combined impacts of sea-level rise and land subsidence on storm tides induced flooding of the Huangpu River in Shanghai, China , 2013, Climatic Change.

[25]  Attilio Castellarin,et al.  Probability-weighted hazard maps for comparing different flood risk management strategies: a case study , 2009 .

[26]  Christophe Viavattene,et al.  Guidance for assessing flood losses CONHAZ Report , 2011 .

[27]  B. Merz,et al.  Is flow velocity a significant parameter in flood damage modelling , 2009 .

[28]  Annegret H. Thieken,et al.  Review article: assessing the costs of natural hazards - state of the art and knowledge gaps , 2013 .

[29]  N. J. Lim.  Performance and uncertainty estimation of 1- and 2-dimensional flood models , 2011 .

[30]  F. Dottori,et al.  Detailed data is welcome, but with a pinch of salt: Accuracy, precision, and uncertainty in flood inundation modeling , 2013 .

[31]  M. Marfai,et al.  Tidal inundation mapping under enhanced land subsidence in Semarang, Central Java Indonesia , 2008 .

[32]  G. Bitelli,et al.  Levelling and GPS networks to monitor ground subsidence in the Southern Po Valley , 2000 .

[33]  Nicole Goutal,et al.  TELEMAC: A new numerical model for solving shallow water equations , 1991 .

[34]  P. Bates,et al.  Progress in integration of remote sensing–derived flood extent and stage data and hydraulic models , 2009 .

[35]  G. di Baldassarre,et al.  Socio-hydrological modelling of flood-risk dynamics: comparing the resilience of green and technological systems , 2017 .

[36]  R. Nicholls,et al.  Subsidence and human influences in mega deltas: The case of the Ganges-Brahmaputra-Meghna. , 2015, The Science of the total environment.

[37]  F. Dottori,et al.  Investigating the influence of minor hydraulic structures on modeling flood events in lowland areas , 2014 .

[38]  G. Blöschl,et al.  Socio‐hydrology: A new science of people and water , 2012 .

[39]  D. Rudolph,et al.  Analysis of long‐term land subsidence near Mexico City: Field investigations and predictive modeling , 1999 .

[40]  Bruno Merz,et al.  Probabilistic flood hazard mapping: effects of uncertain boundary conditions , 2013 .

[41]  Demetris Koutsoyiannis,et al.  Comparative evaluation of 1D and quasi-2D hydraulic models based on benchmark and real-world applications for uncertainty assessment in flood mapping , 2016 .

[42]  C. Schmidt.  Delta Subsidence: An Imminent Threat to Coastal Populations , 2015, Environmental health perspectives.

[43]  Bruno Merz,et al.  Multi-variate flood damage assessment: a tree-based data-mining approach , 2013 .

[44]  P. Bates,et al.  Identifiability of distributed floodplain roughness values in flood extent estimation , 2005 .

[45]  G. Tsakiris,et al.  Comparing Various Methods of Building Representation for 2D Flood Modelling In Built-Up Areas , 2014, Water Resources Management.

[46]  Giuseppe Gambolati,et al.  Mathematical Simulation of the Subsidence of Ravenna , 1991 .