Pilot service: Southern Emilia Romagna (Italy)

Transcription

1 Pilot service: Southern Emilia Romagna (Italy) Surface deformation service provider (PSInSAR TM ) Geodetic and optical remote sensing data integration Final user

2 The study area

3 The Southern Emilia-Romagna Pilot Case Valuable touristic area Highly urbanized areas and agricultural zones Increasing in water withdrawal from shallow depths, mainly for civil use Increase in the hazard of flooding Actions have been taken by regional authority with the aim of removing the causes of subsidence, protecting the coastline by sand replenishment, etc.. Coastal area near the Apennines foothills

4 Along the regional coast, more than hectares are below the sea level The Emilia-Romagna Coastal Area

5 High economic importance Due to the high economic value of the real estates built close to the beach, coastline retreat must be avoided

6 Sea water ingression In the period the coastal area was interested by sea water ingression phenomena extended over the years from the Po Delta to the South Stato del litorale emiliano-romagnolo all anno 2007 e piano decennale di gestione, I Quaderni di Arpa, 2008

7 Damages Due to Sea Water Ingression Cesenatico

8 Defense structures Cesenatico, Porte Vinciane (2005) The whole coastline is highly vulnerable and permanent or temporary (winter) defense barriers have been implemented along dozens of kilometres of coastline.

9 Topo-bathymetric surveys In order to follow the evolution of the erosive processes on the littoral and quantify its importance, in 1984 the Region has set up topo-bathymetric cross-shore profiles. Beside 1984, the net has been leveled 3 more times: in 1993, in 2000 and in The data were used to form detailed bathymetries and DEMs of the littoral areas. The results of successive campaigns were used in order to compute the sediment balance in front of each reach of coast. Shoreline evolution is also monitored by repeated surveys. Bathymetric map, 2006

10 Coastal area Subsidence Map Densely populated Tourism Natural resources Areas below sealevel Fluid withdrawal Risk of salt intrusion Quaternary sediments Local monitoring actions since 1980 Monitoring the subsidence (anthropogenic + natural) is crucial for the coast.

11 Subsidence cumulative effects Rimini in certain areas has dropped by 70 cm in 55 years

12 Modelling by ARPA ARPA is producing a complex model for underground waterflow of the Marecchia fan, near Rimini, to be used to support a sustainable management of water resources. High resolution subsidence data are required to validate the model

13 Strategic actions for the defense and the requalification of the environmental littoral system of the Emilia Romagna region. The defense has followed criteria of a proper integrated management. Stato del litorale emiliano-romagnolo all anno 2007 e piano decennale di gestione, I Quaderni di Arpa, 2008

14 Subsidence monitoring in the Emilia-Romagna region Emilia Romagna region is affected by a strong subsidence mainly due to human activity. The phenomenon was firstly evidenced in the Seventies and reached significant values Most evident effects: damages on historical monuments loss in the efficiency of water management systems erosion of the coastline increasing flooding risk The phenomenon has been monitored by numerous agencies and authorities, through control surveys characterized by: different degree of accuracy different time periods different areas different benchmarks and altimetric reference systems

15 Historical data: leveling surveys IGM: 1950, 1970, 1990 Catasto: 1977 Consorzio di Bonifica Forlivese: IDROSER SpA: 1984, 1987, 1993 ARPA Emilia-Romagna Regional Network: 1999, 2005

16 Regional network for subsidence monitoring Project developed since 1997 by Regional Agency for Health Prevention and Environmental Protection (ARPA) on behalf of Emilia Romagna Region and in collaboration with University of Bologna Main purposes: cover the overall Southern part of the Po River Valley (9000 km 2 ) establish a well defined spatial-temporal frame for future monitoring of the total area or portions provide the possibility of using data coming from historical surveys by including in the network some old lines and their reference benchmarks Surveying techniques: high precision 1 st order spirit levelling 2 integrated networks static GPS network

17 Regional network for subsidence monitoring The 1999 leveling network Area: 8609 km km of leveling lines, about 2336 uniformly distributed benchmarks (30% of new realization in areas not previously monitored). More than 50 closed polygons Max m.s.e. 6-7 mm Error per km < 1 mm 75 days Reference height: benchmark in Apennines, in a stable area, near the region barycenter - height determined in the past by National Geographic Institute (IGM) The network is constrained through 6 open lines to existing benchmarks on stable areas on the Apennines

18 The regional network in the area

19 From Rimini to Ferrara ( ) The rate of subsidence along a transect

20 Regional network for subsidence monitoring The GPS network 59 vertices, 12 located in stable areas Almost all GPS vertices measured also by levelling: study of geoidal undulation Use of permanent stations available in the region for datum establishment Instrumentation: dual frequency GPS geodetic receivers High redundancy: 222 GPS baselines Measurement strategy: 2 phases Framework of the network (10 stations connected to IGS permanent stations, long sessions) Whole network (minimum session lenght: 270 minutes, 540 and 810 minutes for long baselines) Campaigns:

21 Database & Information System Data integration and data management

22 Regional network for subsidence monitoring 2005: spirit leveling campaign (50% of the regional network, ~ 1000 km) in support/calibration of radar interferometric analysis PSInSAR TM (T.R.E. TeleRilevamento Europa, regional analysis) for the whole Po plain regional area Permanent Scatterers ERS Permanent Scatterers ERS ERS + Envisat + Radarsat

23 PS vs leveling benchmarks density PS (average density 8 PS/km 2 ) and leveling benchmarks

24 Final results ERS data Envisat and Radarsat data Small decrease of subsidence rates in most areas

25 Ongoing SubCoast activities Collection and analysis of existing literature and datasets: Natural and anthropogenic causes and effects of subsidence in the area Medium and large scale vector maps (e.g. 1: :2000) GIS layers: Landcover/Landuse, Infrastructures and transportations, Flood risk Geological maps Sea level rising data Lidar data Geodetic data 1 st order spirit leveling GPS permanent stations GPS data processing from existing permanent stations in the area for time series analysis Execution of specific leveling survey(s) for data validation

26 SAR data: planned activities Acquisition and processing of multi-geometry and multifrequency SAR data: CosmoSKY-Med descending dataset (X-Band) TerraSAR-X ascending (X-Band) Radarsat-1 ascending and descending (C-Band) InSAR derived LOS motion measurements will be used for 2D characterization of the subsidence (Vertical and East- West motion component estimation)

27 Example of X-band data in urban area

28 Some expected output High resolution subsidence map, updating existing knowledge of the phenomenon Validation of SAR results by geodetic measurements Validation of the waterflow model developed by ARPA High resolution DSM... The results of this project will allow to characterize with high level of detail the area under study, to support modeling activities of the end user and to set the framework to replicate the experience in other coastal areas prone to flood risk

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