Port of Miami Tunnel: Resiliency Through Flood Gates
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CASE STUDY PORT OF MIAMI TUNNEL: RESILIENCY THROUGH FLOOD GATES ACHIEVEMENT: TUNNEL FUTURE-PROOFED AGAINST SEA LEVEL RISE AND CLIMATE CHANGE CAPITAL COST OF TUNNEL FLOOD GATES: $4.8M POTENTIAL COST OF A MAJOR STORM WITHOUT THE GATES: $1BN+ BUILDING RESILIENCE TO CLIMATIC RISKS The Port of Miami Tunnel, on the state’s eastern coast. Severe construction, financing and operation storm surges, like that experienced of the tunnel in 2009. Before then, connecting the city with from Hurricane Irma, can cause water as the scheme was being developed, its port on Dodge Island, levels to rise several metres, breaching there was a clear need for protection the city’s existing defences; and against flooding. is protected against scientific analysis shows the risk of flooding by a pair of heavy flooding is likely to get worse. “The idea for the gates came from Meridiam CEO, Thierry Déau. He was in flood gates at each end. In this context, a road tunnel beneath the room when our proposals for the Activated through hurricane Miami’s port waterway is susceptible tunnel were being discussed at the to extreme risk of flooding. However, conceptual design stage,” says MAT preparation procedures, the Miami Tunnel has distinctively Concessionaire CEO, Chris Hodgkins. the gates help to make this iconic yet practical features at each end: concrete portal structures which Flood gates on the tunnel portals were modern infrastructure asset house a pair of solid steel flood gates. a necessary solution to a serious predicament for the project. The highly resilient to the risk of Each gate – there are two at both proposal was for a twin-bore road flooding. portals, one for each tunnel bore – is a tunnel to connect the Port of Miami steel box section just over 31 ft. (10m) on Dodge Island with the MacArthur wide by 36 ft. (9m) high and weighing Causeway on Watson Island. For road around 55 tonnes. They are housed freight and other port traffic, this would Each year during hurricane season, in commanding structures, which rise provide a highly valuable direct link between the beginning of June and up from the bottom of the tunnel’s with the mainland Interstate highway the end of November, Florida will be hit approach ramps, providing essential network, bypassing downtown Miami. by anything from 10 to 20 hurricanes. protection against flood risk. But risk of flooding was high at the On occasion, it suffers the brunt of a tunnel portals on the two low-lying powerful category four or five storm, The organisation responsible for islands. like Hurricane Irma which struck the overseeing operation of the tunnel peninsula in September 2017 with wind is Miami Access Tunnel (MAT) “The flooding risk made the project speeds exceeding 150mph (241kph). Concessionaire LLC, which is owned infeasible to begin with. We would not by Meridiam and its co-investors, have been able to obtain insurance for Greater Miami is particularly vulnerable which developed the POMT project the tunnel. But with the addition of to damaging floods as well as high in partnership with the Florida the flood gates, insurance became not winds during hurricane season. Florida Department of Transportation (FDOT). only possible, but it has subsequently is mostly a low-lying state and Miami is MAT and FDOT signed a 35-year become considerably less expensive one of its most heavily built-up areas, concession agreement for the design, than policies for other comparable P.2 infrastructure assets, which Aesthetically, the portal structures and extreme weather events in have experienced increases in were designed with local general. insurance costs,” Chris says. heritage in mind, to enhance their visual impact. Conjugations Hurricane Irma hit in 2017, then Construction of the POMT of the word ‘Navigate’ have been came Hurricane Florence a year project was carried out between imprinted in Latin on the concrete later. Florence made landfall 2010 and 2014 (the new road link towers which house the gates. further north, missing Florida, but opened on the 3rd of August that becoming the largest and most year), complete with one-mile- Looking at the POMT from a devastating storm on record to long tunnels, portal structures broader perspective, this modern hit the States of South and North and flood gates, new road layouts addition to Miami’s infrastructure Carolina. on both islands and a widened has become part of a wider MacArthur Bridge connecting discussion on the need for “Improving resilience is the hot with the mainland. greater resilience to flooding topic that everyone is talking INCREASING RESILIENCY GLOBALLY 100 Resilient Cities is an initiative of the Foundation and managed as a sponsored Rockefeller Foundation, with the stated aim of project by Rockefeller Philanthropy Advisors – an “helping cities around the world to become more independent non-profit organisation. resilient to the physical, social and economic Cities in the 100RC network are provided with challenges that are a growing part of the 21st resources necessary to develop a roadmap to century”. Meridiam is working with 100 Resilient resilience along four main ‘pathways’: Cities to provide support through case studies on • Financial and logistical guidance for appointing and analysis of contractual and funding structures a Chief Resilience Officer, who will lead the city’s to procure essential infrastructure projects in resilience efforts cities. • Expert support for development of a robust Resilience Strategy Launched in 2013, with an initial group of 32 • Access to solutions, service providers and cities, including Greater Miami and the Beaches, delivery partners from public, private and two further rounds of bidding for places in the NGO sectors for developing and implementing 100RC Network have been carried out. The list resilience strategies now totals 100 cities which are drawing up • Membership of a global network of member strategies and can apply for financial support. cities for learning and helping each other. 100RC is financially supported by the Rockefeller P.3 about, because of the increasing flooding and storm events in the 100 years unless something is number of ever more extreme US, says Chris. For MAT, however, done about it, but the city appears events,” Chris says. “The POMT is a recent flood risk assessment has to have recognised this and is now central to the discussions, in Florida resulted in a $120,000 reduction in acting to reduce the risks,” says at least, because it was the first property insurance premium. Chris. and so far only project of its kind to have flood resilience built-in Storm surges combined with The cities of Miami, Miami Beach from the start. We’ve proved the rising sea levels present an and Miami-Dade County have economics of providing resilience, increasing threat to Miami and teamed up to form the ‘Resilient showing that it’s good business.” its surrounding communities, Greater Miami and the Beaches’ many of whom reside at less than (GM&B) partnership, which has Besides making the POMT one metre above mean high tide successfully applied to join project feasible, from a basic levels. Forecasts vary for how the International 100 Resilient cost benefit analysis, the flood much sea levels will change in Cities Network (see box 1). With gates account for around $4.8m future. Regardless of whether support from 100 Resilient Cities, – less than 1% – of the project’s climate change is due to human GM&B is expected to launch a total $600m construction cost. activity or not, which is a separate comprehensive new resilience “The flood gates do not just argument, sea level predictions strategy in 2019. protect the tunnel’s roadway from for the year 2100 vary from a rise flooding. They also guard against of 31 inches (787mm), according Meanwhile, Miami has POMT as damage to mechanical, electrical to the UN’s Intergovernmental an example of an infrastructure and safety systems. Without the Panel on Climate Change (IPCC), asset that can endure the twin- gates, the effects of a category to the 81-inch (2m) rise calculated threat of extreme weather and four storm could cost as much as by the US National Oceanic and sea level rise. $1bn,” Chris says. Atmospheric Administration. Since the tunnel opened in The actuary work of insurance “Even at the IPCC’s lower predicted August 2014, the gates have been companies has “undoubtedly rate of sea level rise, virtually all of lowered three times in anticipation stepped-up” in the wake of recent Miami will be under water within of significant flooding events, in CLOSURE AT ACTION LEVEL 3 During a storm event, full closure of the POMT to traffic, including lowering of the flood gates, is initiated at ‘Action Level 3’, when notification of ‘Hurricane Condition Yankee’ is made by the Miami Coastguard. At this stage, the port and wider Miami area have already made preparations required at Hurricane Conditions Whiskey and X-Ray. At Yankee, tropical storm force winds are expected within 24 hours. All staff and employees are notified of the change of condition and procedures set in place for a ‘Severe Weather Closure procedure’. This is communicated to motorists via dynamic signs and radio of the city’s traffic management system. “We inform all of our employees and stakeholders of the imminent closure of the tunnel, but we let but we let the Captain of the Port take the lead on communications as we ultimately are its tenant or customer,” says MAT Concessionaire Operations Manager, Wendy Conforme. “Well trained staff that knows how to flawlessly execute our hurricane procedures is paramount in critical events like this. Additionally, throughout the year we ensure proper maintenance of the gates and all drainage and safety systems in order to avoid last minute incidents.