Former flood management plans and interplay with the floods directive in the Arno River Basin Brussels, 29th October 2010
Marcello Brugioni Arno River Basin Authority
[email protected]
Italy and the management of floods
Polesine, 1951 Firenze, 1966
Serchio River, January 2010 Versilia,1994 1996 Piemonte, Savona, 1992 1987 1998 Genova,Valtellina, 4th Sarno, October 2010 Many heavy floods have hit Italian territory Genova, 1970
The floods and the city of Florence
1844
1966
Since 1177 the Arno river has flooded Florence 56 times. 8 occurrences have been defined extreme: 1333 – 1547 – 1557 – 1589 – 1740 – 1758 – 1844 - 1966
The Italian route in the mangement of floods Major disasters (1951, 1966…)
February 2010 implementing law
1989 Wireframe law on soil protection
1990 Institution of RBAs
2007 Floods Directive 2007 Completion of PAI mosaic
2000 Water Directive 1998 Disaster of "Sarno"
1998 “Sarno” Law
1999 Preliminary mapping
1998 Start of PAI planning
Before the “Flood directive”: the Italian model in 5 headings 1. 2. 3. 4. 5.
Only one subject Planning as the main issue Basin scale A “River basin authority” Two time scales
Flood and landslide risk Every action has to be considered and water resources within a holistic planning activity. define a unique and Planning processthematic is open to management environment institutions is and Watershed thestakeholders. planning scale, The plan isoffinally approved regardless administrative by the Prime minister with both boundaries A specific “Authority” and has the of a State law. regional andforce state Basin planning is a components typical governs planning and budgeting “deferred time” scale action. “Real time” action is governed by Civil Protection System.
The RBAs (since 1989):
7 National River Basin Authorities 15 Interregional River Basin Authorities 28 Regional River Basin Authorities
The PAIs (hydrogeological Plan) are active throughout the Italian territory since 2007
The Districts (since 2006) 8 districts that include the national, interregional and regional Basin Authorities The National River Basin Authorities in earlier 2009 were responsible for coordinating and carrying out plans of “water directive”. The water management plans of eight districts were approved in February 2010 The floods directive was implemented with the D.Lgs. 23/2010, in February
So far the District Authorities have not been established yet
The Arno River Basin case: PAI Plan
Hazard: On 4 scenarios: From 30 to 500 ys. return period. Hydraulic modeling and historical records ….
The maps Elements at risk From numerical cartography
Exposure assessment for different scenarios
Risk mapping into classes
Two Scales: 1:25.000 historical records 1:10.000 hydraulic modeling
Hazard classes PI4 = Tr (return period): 1 to 30 years water level h > 30 cm PI3 = a) Tr: 1 to 30 years, water level h < 30 cm; b) Tr: 30 to 100 years, water level h > 30 cm.
PI2 = Tr: 100 to 200 years PI1 = Tr: 200 to 500 years
The Arno River Basin case: hazard map
The syntesis level based on the floods which occurred in the past and on the geomorphological criteria (scale 1:25.000)
The hazard in the Arno River Basin: some examples
The detail level based on hydrological and hydraulic modeling along the Arno river and its main tributaries (scale 1:10.000)
City of Florence
The hazard in the Arno River Basin: some examples
Elements at risk Florence Railway station [208] Platform Florence Railway station [211] Railway station
San Lorenzo Market [202] Industrial/Commercial building Civil building [201] Civil/administrative
Basilica di S. Maria Novella [203] Worship building in [226] religious area Convent of S. Maria Novella [201] Civill/Administrative in [226] religious area
Battistero [203] Worship building in [226] religious area
From 1:10000 numerical cartography we can obtain the characterization of over 600.000 building polygons, infrastructures (e.g. roads, railroads, bridges…) and more
Risk mapping: R = H x V x E
Potential area flooding
Inactive lateral weirs
Area flooding
The flash flood hazard in the Arno river Active lateral weirs basin: a proposal
The climate change scenarios Heavy rainfall hazard map
Spatial distribution of short, heavy rainfall events frequency (return period distribution for 50 mm/hr) Derived from DDF curves and interpolated after a spatial distribution analysis
The climate change scenarios Susceptibility to a flash flood response
Classification of small-size catchments depending on “corrivation time” (from 6 hours to minutes)
Tendency of small-scale catchments to transform heavy, short precipitation events in very high discharge levels
Conclusion •The PAI maps of the Arno River Basin meet the requirements of the Directive as “preliminary flood risk assessment product” to be concluded in 2011. •The PAI Plan of Arno River Basin includes financing programs, structural and no structural actions •The review and the upgrade of maps, also for the climate change scenarious, also meet the “Flood mapping product” requirements deadlined for 2013 and for the 2015 management plan. •We have an important background of knowledge and experience in flood management and we can give significant contributes in this area.
Thank you!!
