3/23/2012

This week's map: What's Your Coastal Flood Risk?

The Climate Central published, last week, an interested interactive map showing spatial implications along U.S. coasts from sea level rise and storm surges. For those who live in the U.S., it is an interesting tool for many reasons.
Surging Seas National Map, 2012 © Climate Central

Suggested article: Claudia Tebaldi, Benjamin H Strauss and Chris E Zervas, Modelling sea level rise impacts on storm surges along US coast, 2012.

This map can be helpful for countries threatened by similar risks such as Thailand, Philipines but also Venice, too. Even coastal cities in France or in Japan may find very useful to have such a tool as they are concerned with flooding risks.
In the website Sea Level, Michael D. Lemonick provides some instructions to use this map:
Just type in your ZIP code or the name of your community, choose a water level anywhere from 1 to 10 feet above the current high-tide line, and you can see what areas might be at risk of flooding from water that high. You can also go to any one of 55 tide gauges we studied around the country, and see the odds we've calculated for how soon flood waters may reach diffeent elevations as the sea continues to rise.
I took Jacksonville, Florida, as example to examine spatial implications of flooding events along U.S. coasts. All the estimations below are based on mean estimations from the interactive map over the period 2020-2100. The projective calculation is based on various heights of sea level rising (SLR) from 1ft to 10 ft. The maps below shows progression of floods and vulnerability of Jacksonville and its area causing by SLR and Storm surges. What does this map inform us?
By 2020, A one-foot storm surge could flood more than 5,270 acres affecting a population of 2,351 and more than 996 homes. Note that the nearest flood risk indicator sites appear to be Fernandina Beach and Amelia River located at 25.9 miles away so that you can focus on these areas if you want a close-up.
Unsurprisingly the warmer the temperature, the higher the water level, the worse the conditions of the ecosystem. As a result, Jacksonville would be becoming more and more vulnerable.
Sea Level Rise (mean estimate), Jacksonville, Florida, © Climate Central, 2012
Water level: 1ft
Forecaste decade: by 2020 
By 2060, a four-foot storm surge would submerge 14,090 acres. As a result, more than 11,406 people would be affected; 6,141 homes would be damaged. This map shows a progression of floods in the interior land resulting in impactful consequences on built as well as natural environments along the coast.
Jacksonville, Florida, © Climate Central, 2012
—> Water level: +4ft,
Forecaste decade: by 2060

By 2080, this will be 16,696 acres inundated by a five-foot water level. Comparison to the previous map indicates that the difference (+4ft by 2060) is negligible. But the progression of flooding events remains constant.
Jacksonville, Florida © Climate Central, 2012
—> Water level: +5ft
Forecaste decade: by 2080
Over one decade, by 2100 as the map stresses an important progression of flooding events. More than 64,523 acres will be flooded and 47,147 homes will be destroyed having a serious impact on 105,563 people.
Jacksonville, Florida © Climate Central, 2012
Water level: 10ft
Forecaste decade: by 2100
Now let's focus on Amelia River and its areas. I chose five decades: 2020, 2060, 2080, 2100 and 2100 and more. The following maps show precisely the progression of floods submerging gradually the surroundings of the Amelia River.

Suggested article: Kaid Benfield, Nine low-tech steps for community resilience in a warming climate, 2012.

This would lead to a shrinkage of the landscape, and, with evidence, to a landscape pattern change affecting accordingly the ecosystem and the infrastructure.
Amelia River — Jacksonville, Florida © Climate Central.
Water level: 1ft
Forecaste decade: by 2020
Amelia River — Jacksonville, Florida © Climate Central.
Water level: 4ft
Forecaste decade: 2060
Amelia River — Jacksonville, Florida © Climate Central.
Water level: 5ft
Forecaste decade: by 2080
River Amelia — Jacksonville, Florida © Climate Central.
Water level: 6ft
Forecaste decade: by 2100

Amelia River — Jacksonville, Florida © Climate Central.
Water level: 10ft
Forecaste decade: by > 2100
This map is very easy to use and provides interesting information on likelihood flooding events in the U.S. coasts. In a age of global warming, rising sea levels and storm surges will be affecting coastal areas and damaging land, insfrastructure, and ecosystems causing displacement of population and non-human species, and huge losts, in coming decades, as the earth is getting warmer. In this context, it is urgent for urban policies to tackle this issue to respond and pose new ways to operate in areas at risk. 

We know that the water level will grow and reach new heights. As the authors of this paper Modelling Sea Level Rise Impacts on Storm Surges Along US Coasts reported in the introduction:
These trends will likely force changes in risk assessments related to extreme events, such as the delinearation of 100 yr floodplains, that influence coastal policy and development.

Reengineering our cities and infrastructure in more ecological and innovative ways will require multidisciplinary approaches with the intersection of architecture, urban planning, civil engineering, science, biology, to name only a few to develop new techniques and a new vision of city planning in these areas. Let's say: our current approach of cities and infrastructure — or should I say the current condition of cities and infrastructure — is obsolete. So are building materials, manufacturing and fabrication.

Urbanization in 19th and 20th centuries was impactful, as it mainly forced to degrade environment. Now that we are shifting into a new paradigm, urbanization of the 21st century will be forcing to take warming trends into consideration by designing ecologically resilient coastal areas. One solution among many others can be to keep future buildings out of those zones

Suggested article: Letter from the Editors, Stephanie Carlisle and Nicholas Pevzner, Landscape Urbanism, Winter 2011.


Yet, it is very difficult for the population living along the coasts, to accept to leave for much farther areas. This is the case for the population of affected coastal areas in the Northeastern Japan who wants go back to their furusato or homeland. In this case, what can we do? Can the redefinition of zoning and building codes help avoid constructing in these areas? If so, will they be enough? The question remains unclear as consequences of flooding threats along coastal zones are unclear, too. But flooding will be increasing fast.

Let's hope that these instruments, starting with this map, will be useful for urban planners, architects, and all the actors that are in charge of city planning.

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