R7C-Approve Desired Minimum Elevation For Crown Of Roads In The CityCOMMISSION ITEM SUMMARY
Condensed Title:
A Resolution Of The Mayor And City Commission Of The City Of Miami Beach, Florida, Approving A
Desired Minimum Elevation For The Crown Of Roads ln The City To Be One Foot Higher Than The
Tailwater Boundary Condition Elevation Established By The Mayor And City Commission To Allow For
Proper D Within The Citv And Protection From Tidal Floodi
lntended Outcome Su
Well maintained infrastructure
Item Summary/Recommendation :
The City is heavily investing in infrastructure improvements in order to mitigate flooding and meet the
challenges of sea level rise. The benefits from having new storm water pump stations, check valves, and
raising streets with low elevation will work collectively to maximize the effectiveness of these drainage
systems and minimize flooding on the streets. A new minimum standard for the crown of road will set
elevations of the cross section of the road.
Resolution 2014-28499 was passed by City Commission on February 12,2014 which modified the tailwater
elevation from 0.5 feet NAVD to 2.7 feet NAVD in the Stormwater Management Master Plan for all tidal
boundary conditions. The result of this modification creates a condition where engineering principles
dictate that inlet elevations be set no lower than the 2.7 leet NAVD. Since the inlets are placed at the
lowest point in the road, the crown of road will typically be a minimum of four to eight inches above that
elevation. Setting the crown of road one foot above the tailwater criteria is already consistentwith the prior
direction.
Not all roads in the City are below the proposed elevation, but there are some that have been historically
prone to flooding due to tidal events. Setting this criteria will allow the City to maintain better drainage for
safer travel during potential flooding events. lt will also extend the useful life of these new roads by raising
the base foundation material such that it will not be saturated with water, reducing cost for reconstruction in
the future and less construction impacts in our neighborhoods.
The City is currently working on a project on West Avenue, from Sth to 8th Streets, the short section on 6th
Street, between Alton and West Avenue, as well as a project on 17th Street, between Alton and the bridge
and a section of West Avenue, from Lincoln Road up to 17th Street. As part of the project, Bergeron Land
Development lnc. (Bergeron) has been assisting the City in developing concepts related to street
elevations, which will be required in order to raise the streets to a level that will be less susceptible to
flooding. A typical design section is attached for four separate locations/scenarios within this project area.
Atthe December 10,2014 Flooding Mitigation Committee meeting, a presentation of thesefourscenarios
was made by Bergeron regarding the existing road conditions and the result of raising the roadway, in
relation to the finished floor elevation of the adjacent properties. ln order to maintain access to those
businesses and obtain the overall desired infrastructure, a harmonization or transition from the proposed
roadway elevation down to an existing finished floor elevation will be required in some cases. During the
presentation different harmonization alternatives were presented to the Committee so that initial concerns
could be discussed. The Committee talked through the concerns with the alternatives presented and
requested that this item be brought to a full Commission for further discussion.
THE ADMINISTRATION RECOMMENDS ADOPTING THE RESOLUTION.
Board Recommendation:
Financial lnformation :
Financia! lmpact Summary:
Clerk's Office
Eric Carpenter, Public Works X6012
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AfiENDAYTEffi R7C# MIAMISTACH Dlrll 2rtl-t{536
g MIAMIBEACH
City of Miomi Beqch, 1700 Convenlion Center Drive, Miomi Beoch, Florido 33I39. www.miomibeochfl.gov
COMMIS MEMORANDUM
TO: Mayor Philip Levine and of the
FROM: Jimmy Morales, City Manager
DATE: February 11,2015
SUBJECT: A RESOLUTION OF THE MA AND CITY COMMISSION OF THE CITY OF MIAMI
THE RECOMMENDATION OF THE FLOODINGBEACH, FLORIDA, ACC
MITIGATION COMMITTEE, KNOWN AS THE (SUSTAINABILITY AND REStLtENCy
GoMMITTEE), AND APPROVING A DESIRED M|NIMUM ELEVATTON FOR THE
cRowN oF RoADS rN THE CITY TO BE ONE FOOT (1') HtcHER THAN THE
TAILWATER DESIGN CRITERIA, FOR PROPER DRAINAGE WITHIN THE CITY AND
PROTECTION FROM TIDAL FLOODING.
BACKGROUND
The City is heavily investing in infrastructure improvements in order to mitigate flooding and meet
the challenges of sea level rise. The benefits from having new storm water pump stations, check
valves, and raising streets with low elevation willwork collectively to maximize the effectiveness of
these drainage systems and minimize flooding on the streets. A new minimum standard for the
crown of road will set elevations of the cross section of the road.
Resolution 2014-28499 was passed by City Commission on February 12,2014 which modified the
tailwater elevation from 0.5 feet NAVD to 2.7 feet NAVD in the Stormwater Management Master
Plan for all tidal boundary conditions. The result of this modification creates a condition where
engineering principles dictate that inlet elevations be set no lower thanthe2.T feet NAVD. Since the
inlets are placed at the lowest point in the road, the crown of road willtypically be a minimum of four
to eight inches above that elevation. Setting the crown of road one foot above the tailwater criteria
is already consistent with the prior direction.
Not all roads in the City are below the proposed elevation, but there are some that have been
historically prone to flooding due to tidal events. Setting this criteria will allow the City to maintain
better drainage for safer travel during potential flooding events. lt will also extend the useful life of
these new roads by raising the base foundation material such that it will not be saturated with water,
reducing cost for reconstruction in the future and less construction impacts in our neighborhoods.
The City is currently working on a project on West Avenue, from 5th to 8th Streets, the short section
on 6th Street, between Alton and West Avenue, as well as a project on 17th Street, between Alton
and the bridge and a section of West Avenue, from Lincoln Road up to 17th Street. As part of the
project, Bergeron Land Development lnc. (Bergeron) has been assisting the City in developing
concepts related to street elevations, which will be required in order to raise the streets to a level
that will be less susceptible to flooding. A typical design section is attached for four separate
locations/scenarios withi n this project area.
537
City Commission Memorandum - Street Elevations
February 11,2015
Page 2 of 2
At the December 10,2014 Flooding Mitigation Committee meeting, a presentation of these four
scenarios was made by Bergeron regarding the existing road conditions and the result of raising the
roadway, in relation to the finished floor elevation of the adjacent properties. ln order to maintain
access to those businesses and obtain the overall desired infrastructure, a harmonization or
transition from the proposed roadway elevation down to an existing finished floor elevation will be
required in some cases. During the presentation different harmonization alternatives were presented
to the Committee so that initial concerns could be discussed. The Committee talked through the
concerns with the alternatives presented and requested that this item be brought to a full
Commission for further discussion.
CONGLUSION
The Administration recommends adopting the Resolution.
JMIMv#JJJFIBAM/FRS
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538
RESOLUTION NO.
A RESOLUTION OF THE MAYOR AND CITY GOMMISSION OF THE CITY OF
MIAMI BEACH, FLORIDA, ACCEPTING THE RECOMMENDATION OF THE
MAYOR'S BLUE RIBBON PANEL ON FLOODING AND SEA RISE, AND
APPROVING A DESIRED MINIMUM ELEVATION FOR THE CROWN OF ROADS
lN THE CITY TO BE ONE FOOT (1',) HTGHER THAN THE TAILWATER DESIGN
GRITERIA, FOR PROPER DRAINAGE WITHIN THE CITY AND PROTECTION
FROM TIDAL FLOODING.
WHEREAS, at its February 12, 2014 meeting, the City Commission approved the
recommendation of the Mayor's Blue Ribbon Panel on Flooding and Sea Rise to amend the
Stormwater Management Master Plan's tailwater elevation design criteria from 0.5 FT-NAVD to2.7
FT-NAVD, which dictates a higher crown of road elevation than what exists in some of the areas of
the City; and
WHEREAS, at its January 13,2015 meeting, the Mayor's Blue Ribbon Panel on Flooding
and Sea Rise unanimously approved a desired minimum elevation for the crown of roads in the City
to be one foot (1') higher than the tailwater design criteria; and
WHEREAS, the recommended elevation will maximize the effectiveness of City drainage
systems and minimize flooding on the streets, and will set elevations of the cross section of the road
in order to maintain better drainage and storm water inlet for safer travel during potential flooding
events that may occur; and
WHEREAS, in orderto maintain access to adjacent properties and obtain the overalldesired
infrastructure, a harmonization or transition from the proposed roadway elevation down to an
existing finished floor elevation will be required in some cases.
NOW, THEREFORE, BE IT DULY RESOLVED BY THE MAYOR AND THE CITY
COMMISSION OF THE CITY OF MIAMI BEACH, FLORIDA, that the Mayor and City Commission
hereby accept the recommendation of the Mayor's Blue Ribbon Panel on Flooding and Sea Rise,
and approve a minimum elevation for the crown of roads in the City to be one foot (1') higher than
the tailwater design criteria, for proper drainage within the City and protection from tidalflooding.
PASSED AND ADOPTED this _ day of
ATTEST:
Philip Levine, Mayor
Rafael Granado, City Clerk
City Attorney Date
APPROVEDAS!O
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