HIDRALERTA - FLOOD FORECAST AND ALERT SYSTEM IN COASTAL AND PORT AREAS
Mar 2012 - Feb 2015
Overtopping evaluation for maritime structures in coastal zones and ports is very important to assess the risk related with either the
failure of those structures or the flooding of the regions protected by them. This is also an urgent matter to Portugal, due to the
coastline length, the concentration of population and economic activities close to the sea, its severe sea-wave climate and the
relevance of ports for the national economy.
In fact, emergency situations caused by sea-waves hitting the coast are common, usually endangering the safety of people and goods
and having serious consequences for the economy and society. Recent examples are: the flooding at Esmoriz,
17/02/2011, due to overtopping of the seawall, with damages in the infrastructure and homes along the seafront; the frequent
overtopping of Estoril seawall, which affects its use and disrupts the nearby railway line; the strong overtopping of the breakwaters of
Praia da Vitoria port, completely destroyed after the December 2001 storm; the massive overtopping of the Marina do Lugar de Baixo
breakwater, Madeira, 2006, damaging this structure quite seriously and leading to the marina inoperability. Therefore, it is deemed of
paramount importance to put in operation a warning system that is able to forecast the occurrence of emergency situations and
enables the adoption, by the national or local authorities, of measures to prevent live losses and to reduce economic and
environmental damages.
This system may also act as a long-term management tool since it can simulate the phenomenon response to long series of historical
data thereby enabling the definition of risk maps as well as the study of the response to future scenarios related to climate changes
such as the increase in the mean sea level and/or in the storm severity, which will increase the probability of coastal flooding. It is
worth mentioning that such a system may contribute to complying with the directive 2007/60/CE from the EU of 2007-10-23 in what
concerns the elaboration by the member states of flooding risk maps before 22 Dec 2013 (Chap.III-Art.6-8) and of risk management
plans, including forecast, alert and warning systems, before 22-12-2015 (Chap.III-Art.7-3).
The new Forecasting and Warning System for Floods in Coasts and Ports HIDRALERTA, unique in Portugal, stems from the basic idea
of using the sea wave forecasts to calculate their effects in terms of overtopping and flooding. Comparing these values with predetermined
values will allow: i)real-time assessment of emergency situations, issuing alert messages to the authorities, whenever the
safety of people, property or activities in those areas is at risk; ii) construct risk maps considering either long-term series of forecast
sea wave characteristics or pre-defined scenarios associated with climate change or extreme events.
