This paper is about which mitigation and protection strategies are seen as viable solutions for solving the challenges Florida is facing in terms of sea level rise, flood control and hurricane impact safety and resilience. Based on the Resilient by Nature approach, which finds its origin in what can be learned from coastal zones which face similar impact exposures or even worse and suffer less damage or hardly any at all. Translating those capabilities to areas less flood and extreme weather impact resilient, such as large parts of Florida. Solutions for the affected areas are presented as input towards a safer and much more resilient coastal system for Florida and similar places, with regard to a rapid changing climate, accelerated sea level rise and overall related extreme weather impacts. In order to prevent the situation that large parts of the built environment of Miami and the Keys will become the new Atlantis, sunken and lost cities.

1. ©
Marco
Pluijm,
04/12/2016
Artist's conception of what encroaching water could do to the mid-beach area. Ref. Photo-
Illustration by Darrow; © Richard Cavalleri / Vanity Fair
Making Florida Flood Impact Resilient by Nature
Marco Pluijm M.Sc.
Senior Expert Ports and Coasts
Key Elements: Climate Change; Extreme Event Impacts; Flooding, Adaptation; “Resilient by Nature”
Summary
This paper is about which mitigation and protection strategies are seen as viable
solutions for solving the challenges Florida is facing in terms of sea level rise, flood
control and hurricane impact safety and resilience.
Based on the Resilient by Nature approach, which finds its origin in what can be
learned from coastal zones which face similar impact exposures or even worse and
suffer less damage or hardly any at all. Translating those capabilities to areas less
flood and extreme weather impact resilient, such as large parts of Florida.
Solutions for the affected areas are presented as input towards a safer and much
more resilient coastal system for Florida and similar places, with regard to a rapid
changing climate, accelerated sea level rise and overall related extreme weather
impacts.
In order to prevent the situation that large parts of the built environment of Miami and
the Keys will become the new Atlantis, sunken and lost cities.

2. ©
Marco
Pluijm,
04/12/2016
Introduction
Florida is in one of the US States, challenged extensively by accelerated sea level
rise and climate change extreme weather impacts, such as hurricanes and excessive
downpour. Events, which are happening more often and with much greater intensity
than before and ever anticipated for in terms of response and mitigation. Additional
challenge is the low-lying character of large parts of Florida, such as Miami and the
Keys. Due to which combination of factors, flooding is beginning to rise to excessive
proportions. In order to be able to reduce the effects of inundations and flooding, the
authorities have invested large sums of money in pumping installations.
Which for the short term seems to be a viable solution. However, for the longer term,
without investing in proper means to keep the floodwater out and under control in the
first place, this is probably not to be considered as a feasible option.
Complicating factor in some areas is the porous and highly permeable limestone
which forms part of the geological profile and which may require additional measures
and mitigation in this respect.
Due to frequent flooding, there’s the risk of depreciation of property and devaluation
of the affected areas, often those areas which have invested most, such as the ones
along a waterfront. A trend which has clearly taken off.
In addition, the floods create sanitation issues and impacts on the terrestrial
environment. Valuable vegetation and other characteristic features will get affected
by salt water and can disappear, in which case the landscape is about to change and
some of it can disappear completely.
In order to provide adequate overall response, it is crucial to differentiate between
relative slow developing processes such as sea level rise and high impact events
such as hurricanes. Consequently asking for different solutions.
Plan and Design Data under Pressure
Climate change comes faster and is much more intense than so far anticipated for.
The challenge now is to assess how much faster and the increase in intensity.
Traditionally plan and design data are based on historic data, trend analyses and
statistical forecasting. All with their own uncertainties and bandwidth. As a
consequence of which, given the number of variables involved and the way they
interact, it’s basically unknown what tomorrow will bring in terms of increased
weather activities and how those will impact the plan and design conditions of today.
In all respect, demonstrated by the sheer endless number of scenario’s and data
analysis which are continuously produced in high numbers, without actually
delivering data which can be used for adequate planning and design of extreme
weather impact solutions.
With in there, the given fact that if and when a trend breach will occur, one will only
know when it happens. Simply because you can’t forecast a trend breach.
Reason why alternative plan and design procedures and approaches are required in
order to be able to keep up and encounter the challenges nature is delivering time
and time again.

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Pluijm,
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Resilient by Nature Approach
The Resilient by Nature approach is based on what can be learned from coastal
systems which appear to have a built in natural resilience. Coastal systems and
features which are hit by extreme weather phenomena, often over and over again,
without suffering too much damage or hardly any damage at all. And are able to
recover soon after by themselves or with just a little help from outside.
Within the Resilient By Nature approach, a number of coastal systems with such
natural resilience have been identified and their characteristics analyzed and
translated into parameters, which can be transferred to other, more vulnerable
coastal stretches. By translating and implementing these characteristics as system
components rather than adjusted, engineered designs. Thus delivering sustainable
and resilient solutions. Instead of following a traditional maintenance approach such
as for instance sand nourishments, often applied in those parts of the world with
abundant quantities of sand and contractors who can handle those effectively. Sand
nourishment is an approach which is some kind of effective for the time being, but by
no means a sustainable solution for the longer term. Not even in aforementioned
areas.
Therefore, in order to be able to deal with the climate change impacts as they appear
today and are expected to intensify much faster than originally anticipated for,
tomorrow, such an alternative approach is definitely required. A holistic approach
rather than engineering on the basis of unreliable input data.
Resilient by Nature is such an holistic approach, suitable and appropriate for proper
planning and implementation of safe and resilient coastal impact solutions when it
comes down to dealing with accelerated climate change impacts for coastal areas.
More information about the Resilient by Nature approach and toolbox can be found
on :
www.slideshare.net/MarcoPluijm/hurricane-­‐impact-­‐preparedness-­‐and-­‐resilient-­‐by-­‐nature-­‐
recovery
Towards a Sustainable and more Resilient Approach
Where areas get flooded on frequent basis, such as Miami and the Keys, usually the
first ones to take action are the affected individuals who take the initiative to protect
their assets and limit the damage. For instance to build or raise flood protection
around their land plots or raise the properties themselves by putting them on stilts or
terps (raised grounds). Basically doing the same as the original inhabitants in the old
days when colonizing low lying areas such as the Netherlands.
Which today is basically no longer an option, because many things have changed
since, such as population density and the need for additional infrastructure and
utilities. Reason why such individual solutions are no longer a viable solution when it
comes down to protect communities. And why a more integrated, less individual
approach is an absolute requirement. Which today is supported by many authorities.
Because when an integrated approach fails to get sorted properly and implemented,
the individual efforts will fail eventually as well. Which in this case could mean that

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large parts of the built environment have to be given back to the sea. A trend which
already has taken off.
Consequently there’s an urgent need for integrated solutions which make optimal
use of the assets and resources which are available, sharing what can be shared
and differentiate between various needs and solutions, reducing impacts and
directing the negatives to where they do the least harm.
Adequate sets of coherent and reliable inundation maps and topographical data are
a key element for drawing up such integrated, adequate solutions.
Resilient by Nature based Solutions
The accelerated climate change induced phenomena to deal with here are :
• Accelerated sea level rise, including King Tides, both in frequency and
intensity and so the need for adequate drainage, storage and discharge
capacity
• Extreme weather impacts, leading to beach erosion and decay of coastline
infrastructure, wave set up and storm surges, extreme downpour and flooding
all together and therefore to the need for impact reduction, adequate surface
water run off, storage and discharge.
The current response strategy in Miami (and to lesser extend the Keys) is to
encounter and limit the effects of King Tides and Sea Level Rise induced floods by
means of pumping the water out, once it has got in, in combination with raising flood
defenses and foundation heights in parts of the affected built environment.
As such rather adequate mitigating measures for the moment, but as outlined earlier
by no means a sustainable solution for the longer term.
Differentiation between affected areas on the basis of topography, sea-level rise
predictions and inundation risks can provide fairly reliable indications about how to
prioritize between most and least affected and valued areas and how to direct the
incoming water to adequate storage areas and free run off drains and discharge
facilities. For plan and design purposes, the affected built environment is sub-divided
into mini-watershed areas, zones with equal flood and inundation risk, storage and
run-off capabilities.
One of the essential base materials for planning and design are up-to-date flood
maps and topographic data for all affected and also not yet affected areas, as one
complete set of documents.
Additional feature, when preparing for this Florida flood and impact analysis, is that
multiple references were found with regard to the porosity of large parts of the
subsoil. Which is believed to be a relevant given, however of limited impact with
regard to flood-water intrusion and management.
The actual impact of subsoil porosity with regard to salt water intrusion and related
flooding is considered limited due to the characteristics of groundwater flow in direct
relation to the water surface elevation (gradient during the tidal cycle) and the limited
duration of that tidal cycle. However under those circumstances where the internal,
landside response would be almost equal to the outside waterlevel changes,
solutions like enhanced vertical drainage and/or deep penetration with artificial or

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natural sealants (silt, clay) can be considered as options to reduce and redirect the
seepage in combination with adequate horizontal drainage, storage and discharge,
either natural (free flow during low tide) or by pumping.
In case of the additional extreme weather challenges Florida is facing, such as
hurricanes and storm-surges, most appropriate natural solutions are considered to
be the creation of hurricane impact barriers and sub-division of coastal stretches into
low impact entities, all together reducing wave attack, set up and surge by means of
creating guided flow and overflow (wash) conditions.
Hurricane shaped barriers as referred to in the Resilient by Nature approach and
toolbox, differ from traditional offshore breakwaters in the sense that their efficiency
is based on controlled over-wash and gradual wave energy dissipation and surge
reduction.
With respect to the net effect of sub-dividing coastal stretches into smaller hydro-
morphological units, reference is made to a paper about the subject called “Hurricane
Impact as Resiliency Master Class”, to be accessed via :
www.slideshare.net/MarcoPluijm/hurricane-impacts-as-resiliency-master-class-11112016
Sub-dividing coastal stretches in more stable hydro-morphological units, with proven
net results under hurricane conditions, properly laid out, can make a substantial
difference of decimeters reduction in wave set up, surge and related currents. And so
reduction of dynamic and static waterlevels along the affected coastlines, limiting
impacts such as erosion and flooding.
In addition, these overflow barriers can be designed as such that activities on the
surface can be developed within the clear understanding that during the extreme
event ,free flow over the barrier is guaranteed.
Conclusions
Time’s up if we don’t want Miami and the Keys to become the new Atlantis, to
become lost and sunken cities.
Current initiatives by local authorities and individual efforts deserve all respect and
support, but may eventually fail without further integration and system
implementation. Which may result in the fact that part of the built environment needs
to be given up.
Adequate solutions with appropriate funding go hand in hand. Using natural
processes and phenomena are expected to contribute significantly to cost reductions
and savings for all involved.
The Resilient by Nature approach is based on what can be learned from systems
with proven safety features and natural resilience built in, translated to areas which
are less safe and resilient, such as in this case large parts of Florida.
In order to prevent such loss of land and assets, integration of efforts and
concentration of functionalities is an absolute requirement. To secure safe flood
protection infrastructure by connecting flood walls and other infrastructure of
sufficient elevation relative to storm surge levels, including adequate safety margins
and internal redundancy and flexibility. Cost savings can be achieved when

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Pluijm,
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combinations can be made with existing road- and coastal infrastructure and plots of
land with sufficient elevation. Sub-dividing the entire affected area into mini-
watershed entities of manageable size and characteristics.
Equipped with adequate drainage capacity and facilities in order to direct flood water
to the desired locations, such as direct discharge and storage ponds. Instead of
allowing water-masses to accumulate at accidental low lying depressions without
proper discharge capacities.
Free run off and discharge is to prefer over pumping, depending on the level of the
drainage system relative to low water tidal levels.
In addition, where seepage contributes significantly to the overall quantities of
incoming water, enhanced vertical drainage may be required in order to concentrate
the seepage to where it does least harm. Which may require additional deep-
injection with natural sealants, such as clay or silts.
In order to enhance shore line protection against direct storm hits, set up and surge
can be achieved by creating over-wash breakwaters at adequate distances
according to the planning and dimensions as they follow from the Resilient by Nature
toolbox of solutions with proven natural resiliency.
Where needed and effective, in combination with creation of additional onshore over-
wash and discharge capacity in order to reduce water level set up along the
shoreline.
Traditional offshore rubble mound type of breakwaters won’t deliver the required
performance due to their limited dimensions, size, height and hydraulic
characteristics.
Phasing and funding of what’s proposed against what needs to be protected and
when, is subject of further detailing, to be provided upon request.
Resilient by Nature Community
The Resilient by Nature Community is an informal platform for exchange of
information and experiences between people who are interested and/or involved in
coastal systems in relation to extreme weather impact, safety and more effective
resilience. Systems ideally with the potential and capacity to get implemented
elsewhere and to be included as part of the Resilient by nature approach and
toolbox.
More information can be obtained via email on pluijm64@gmail.com