R9F Buoyant City OverviewBUOYANT CITY
Item R9 F
Second presentation by Allan Shulman
to City Commission
October 14, 2020
Client
Team
BUOYANT CITY
4.5’ Sea Level Rise
At an average elevation of just under 3.5 feet above sea
level, this city of barrier islands surrounded by the sea is
among the world’s most vulnerable places. Miami Beach
lives with cyclical flooding from rain events and King
Tides, flooding that will only be exacerbated by the threat
of sea level rise. The city also contends with the always-
present possibility of hurricane storm surge.
BUOYANT CITY
BUOYANT CITY
1.3 // GENERAL RECOMMENDATIONS
1.3.2 // RECONCILE PRESERVATION/ADAPTATION EFFORTS
The City of Miami Beach should undertake a process of reconciliation of historic preservation ordinances and
practices with resiliency-oriented codes and objectives. It should channel the often-disparate discrete decision-
making of various jurisdictional authorities (as well as property owners) into a coordinated vision: it should manage
this process with input from professional and academic sources. The City should incorporate adaptation as a
requirement in all preservation planning, and historic preservation concerns should be carefully integrated into all
adaptation planning and permitting. The City’s Historic Preservation Board should be granted increased authority
over resiliency-based decisions (in the same way it was granted increased authority over zoning variances in the
2010’s.) The city should advocate for changes to the Florida Building Code, the National Electrical Code, FEMA’s
flood plain management guidelines and other national codes that emphasize the particular needs of Miami Beach
(both in terms of preservation and resilient adaptation), and should authorize the City Building Official to interpret the
application of these codes to historic properties in a manner that is consistent with the City’s larger preservation and
resiliency goals.
2.5.1 // Design Flood Elevation
The City of Miami Beach should re-examine the determination and application of Base
Flood Elevation in order to promote and facilitate new development that preloads
anticipated water conditions. It should verify whether the current Base Flood Elevation
is adequate, and should explore whether a more flexible standard for adapting historic
properties is appropriate. The city should consider instituting its own standard, or
Design Flood Elevation. The City should also consider at what point the application of
Design Floor Elevation to existing historic buildings is counterproductive, given the
equally important mission of preserving historic resources and the character of Miami
Beach historic districts.
Following projections from the South Florida Climate Change Compact (SFCCC) out to
2080, data suggests that water levels during cyclical and repetitive events like King
Tides and rain events will exceed current standard of BFE +1 (9.0 NGVD) in the
Flamingo Park and Collins Waterfront districts. Tracking this data, King Tides may
reach 8.4’ NGVD and 10 year rain event flooding may reach 8.6’ NGVD.
The City of Miami Beach should consider setting a new Design Flood Elevation so that
both adapted ground floor levels and the anticipated floor structure beneath them are
above anticipated event flooding. The city should provisionally agree on a set of flood
projections, either following SFCCC or other projections. For the purpose of this study,
we are using 10.0 NGVD as a project DFE.
2.5.2 // RESISTANCE vs RESILIENCE
Following projections from the South Florida Climate Change Compact (SFCCC) out to
2080, data suggests that water levels during a 100year Storm Surge will exceed
current standard of BFE +1 (9.0 NGVD) in the Flamingo Park and Collins Waterfront
districts. Tracking this data, a 100-year storm surge may reach 18.2’ NGVD.
The issue of storm surge flooding raises complex issues, because raising ground floor
levels and their underlying structure to meet these flood levels might imply an
extraordinary and unreasonable amount of raising. As preliminary indications show the
current average ground floor elevation in Flamingo Park district at 6.5’ NGVD and the
current ground floor elevation in Collins Waterfront district at 5.5, and using an average
floor to floor elevation of 10’, this would put even the second floor of most buildings at
risk. Adapting historic building by raising floors would imply raising floor levels between
11.7’ and 12.7’ above current elevation, or more.
Resistance
Adapted building structures should positively resist cyclical and frequent occurrence
water events (King Tide, High Tide, Low Tide, rain events, etc.). This will involve either
raising floor levels, or dry-or wet-floodproofing ground floors and their structures to the
city’s new DFE. This work may include reconstructing floor levels, changing the
materiality of the ground floor, and at times altering ground floor use.
Resilience
Adapted buildings should be upgraded to be resilient to infrequent storm surges (100
year storm surge). This means accepting the water and bouncing back as quickly as
possible. This would certainly indicate upgrading the structure and shell of the building
to withstand storm surge impacts. It may involve wet-floodproofing buildings to
anticipated storm surge levels (for instance by incorporating flood vents), material
change in structure, and the use of flood resistant materials in construction and
finishes.
5.8.1 // REVIEW HISTORIC DESIGNATIONS
The City of Miami Beach should review local and national district designations to study how
adaptation will affect those designations. The city should consider changes/amendments to those
designations that would prepare them for dealing with likely issues connected with adaptation.
Where these designations are constructed on architectural criteria alone (i.e. the Miami Beach
Architectural District), expand the criteria to include cultural and other criteria. Expand the
platform of significance to support the relevance of the districts going forward.
5.8.2 // SELECT A RESILIENCY STRATEGY
The City of Miami Beach should establish Experimental Action Areas (EAA) in each study area,
or a subdistrict of a study area, in order to test resiliency strategies and approaches. Within each
EAA, it should adopt a coordinated, integrated and consistent resiliency strategy (for instance,
select the Adapt in Place strategy, or the Raise strategy, but not both). Within each EAA, it
should emphasize goals associated with the selected strategy. For instance, emphasize
contextual appropriateness in Adapt in Place strategies, and the connection of building to ground
–stoops, planters, entranceways in Raise strategies. The City should allow a period of
experimentation, and commission a review the results. The team vision for implementation of
each strategy is further explained in Chapter 6.
5.8.3 // DEVELOP A TIERED PRESERVATION MODEL
The City of Miami Beach may consider different levels of preservation for different types of
structures.
Tiering is a system in use abroad, such as in the UK, where the Historic England Grading
System has been in place since 1947. Under the English system, historic buildings fall into one
of three grades, based on differing levels of significance: Grade II buildings are of special
interest, warranting every effort to preserve them; Grade II* buildings are particularly important
and of more than special interest; Grade I buildings—the highest grade—are of exceptional
interest.
In Miami Beach, such a tiering system may be based on civic/artistic quality or current degree of
authenticity. The system may emphasize more stringent preservation requirement to capital
structures, while allowing more flexibility in the vastly larger number of modest hotels, residential
and commercial buildings that make up the fabric of the city. Note: such a system should not
be construed as selecting what to preserve, since most buildings that make up Miami
Beach historic district are
modest structures, and the districts are significant for the way these structures work
together to establish character and identity. However, within this fabric, the varied resilience
characteristics of contributing buildings, and the greater importance of the building façade in
establishing significance, argue for more flexibility. The tiered preservation system could work as
follows:
Tier 1: highest degree of civic/artistic quality and degree of authenticity
Example: the Miami Beach Post Office (Howard Lovewell Cheney, 1937)
Allow/require building elevation to minimize impacts to contributing structure. Require low-impact
solutions with minimal effect on interior resources.
Tier 2: moderate degree of civic/artistic quality and degree of authenticity
Example: An oceanfront Art Deco hotel facing Lummus Park, such as The Breakwater (Anton
Skislewicz, 1936)
Allow creative approaches to adaptation, including building elevation; allow some flexibility in
pursuing adaptive use of ground floor, prioritize wet floodproofing as a low-impact solution to
infrequent flooding.
Tier 3: lowest degree of civic/artistic quality
Example: modest residential building type
Focus on maintaining the facades and elements that contribute to the continuity of the
surrounding district. Allow the most flexibility in the interior of the building, including
reconstruction with adaptive materials. Allow elevation in Experimental Action Areas where Raise
has been selected as the appropriate adaptation strategy. Follow resilience design guidelines,
enforced by the HP Board, for most renovations.
Note: Under this system, the City of Miami Beach should tier all buildings (in the same
way all buildings are currently classified as contributing or non-contributing). For the
purposes of this study, the team would consider all buildings in the Flamingo Park study
area and most buildings in the Collins Waterfront study area as Tier 3 structures. Hotels in
the Collins Waterfront study area may be considered Tier 2.
5.8.4 // DEVELOP A TIERED APPROACH TO HISTORIC RESOURCES
The City of Miami Beach may consider tiering of historic resources within each structure/site.
Such a tiered system might give further guidance to the Historic Preservation Board in evaluating
proposed rehabilitation projects in the context of implementing adaptive measures. The tiered
resources model could work as follows:
Over the next 60 years, most buildings in the historic districts of Miami Beach
will need to be substantially rehabilitated/reconstructed to provide necessary
resilience to rising waters. How will this be accomplished, and what type of
city will result? Will these areas survive as historic districts?
BUOYANT CITY argues that Miami Beach’s historic districts should be
preserved, must evolve to survive, and that preservation can be
redeployed as a powerful adaptive tool.The City of Miami Beach
must establish a vision for the future of its historic districts and
create mechanisms that will allow for adaptive development.
BUOYANT CITY
Second presentation to
City Commission
October 14, 2020