LTC 495-2022 Update on City Response to Flooding Event
City of Miami Beach, 1700 Convention Center Drive, Miami Beach FL 33139
LTC# 495-2022 LETTER TO COMMISSION
TO: Honorable Mayor Dan Gelber and Members of the City Commission
FROM: Alina T. Hudak, City Manager
DATE: November 21, 2022
SUBJECT: Update on City Response to Flooding Event
The purpose of this Letter to Commission (LTC) is to provide the Mayor and City Commission
with an update on the most recent flooding event that occurred in our city yesterday.
Consistent rain fell throughout the day on Sunday, November 20, with intense rainfall occurring
from 6 p.m. to 8 p.m. Over 4 inches of rainfall was recorded at City Hall in a 24-hour period, with
the highest peak between 6 p.m. and 7 p.m. Heavy rains combined with an unusually high tide
(1.61 NAVD) at 6 p.m. pushed the stormwater pumps to capacity.
Public Works crews deployed over the weekend to ensure that all stormwater infrastructure was
fully operational. The stormwater pump system, which includes 48 permanent stations, were
operating as designed with no reported malfunctions. Attached is more information on how
extreme rain events cause flooding.
This morning, November 21 we experienced another high tide event at 6:48 a.m. of 1.77 NAVD.
Stormwater teams were deployed to remove standing water, keep drainage inlets and pipes
clean as necessary and following up on all flooding service requests. Given the increased
amount of rainfall expected through Tuesday, we have added more resources including 4 trucks
for stormwater removal and 3 trucks to address sanitary sewer system concerns. City personnel
will remain on extended work schedules until weather conditions improve which is expected by
Tuesday evening.
In addition to our stormwater infrastructure, the Public Works Department has also deployed
temporary pumps in low-lying areas for the upcoming King Tides (November 23 –27, 2022).
Effective immediately, residents may park their vehicles now through Monday, November 28 at
noon free of charge at the 1661 Pennsylvania Avenue and 400 West 42 Street
garages. Residents are required to provide proof of residency when exiting the parking facility.
Messaging will be shared citywide via email, social media and text message.
Should you have any questions, please contact Joe Gomez at joegomez@miamibeachfl.gov
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Letter to Commission (LTC): Update on City Response to Flooding Event
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Attachment.
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Miami Beach is a beautiful coastal community. Our sunkissed island is surrounded by the waters of the Atlantic Ocean
and Biscayne Bay. Miami Beach is leading the way locally and nationally to reduce flood risk, however we want you to be
aware and protect yourself and your property. These efforts are also intended to reduce risk from sea level rise.
Flooding can range from being unexpected, like a fast and heavy rainfall, to being known and communicated in
advance, such as in the case of King Tides and hurricanes.
Weather can be unpredictable. Thinking ahead can keep you safe and reduce damage to your car and home. Think about having sand bags
ready, putting up flood panels, adjusting your work schedule if possible, parking your car in a higher location, and wearing rain boots if you
must be out in the elements. Most of all, many times it is best to stay put and give the stormwater system time to drain the water.
At the start of hurricane season, June 1st, visit www.miamibeachfl.gov, review our Hurricane Guide, and develop a plan for these more
significant events.
WHY DOES MIAMI BEACH HAVE FLOODING CHALLENGES?
• It is difficult to drain a city that is an island, flat, and only a few feet above sea level in many places. Since we are flat, we lack the energy for
drainage created by gravity, and water drains slowly.
• Miami Beach’s hydrology makes draining rainwater difficult. We have a high groundwater that reduces the ground’s ability to absorb
rainwater. In addition, the subsurface is porous limestone, and is affected by the surrounding Bay and Ocean water.
• Many of our outfalls are tidally influenced. An outfall is the location where the stormwater exits the system to a water body. This means
the higher the tide, the more slowly stormwater can drain.
• Miami Beach is densely populated. At only 7 square miles, we lack large open spaces, such as wetlands, to drain rainwater. Impervious
surfaces, hard surfaces like concrete, do not allow rain to soak in. These surfaces contribute to the amount of runoff and how fast the runoff
travels to the collection system.
• If all rain was slow and gentle, we would be less at risk for flooding. However, all rain storms are different.
WHY EXTREME RAIN
EVENTS CAUSE FLOODING
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1. Coastal cities face flood risk. Miami Beach is planning and acting to reduce risk.
2. Protect your property with flood insurance. Flood damage is not covered by
standard homeowner, renter, or wind storm insurance.
3. Be smart if you see flood waters. Avoid driving through or coming in contact
with flood waters.
4. Keep your home and belongings dry. Elevate important mechanical, electrical,
and important items.
5. Build resiliently. Follow the Florida Building Code and Miami Beach Codes.
Understand your elevation by obtaining an Elevation Certificate.
6. Natural systems protect us from floods. Beach dunes, the coral reef tract, and
open green areas are natural flood barriers.
7. Have a plan. We can experience flooding from storms, hurricanes and King Tides.
8. Keep it clean. Storm drains lead to beautiful Biscayne Bay.
9. Financial assistance can help address damage for repetitive loss areas.
10. Miami Beach is here to help. The Building Department offers free technical
assistance.
10 STEPS TO FLOOD AWARENESS
HOW DOES RAINWATER DRAIN? WHAT ABOUT PUMPS?
1. Rain falls to the ground and runs off
impervious surfaces. Stormwater flows across
the land, over parking lots, through swales,
down ditches, along gutters, and eventually
makes its way to storm grates.
2. Stormwater flows into storm grates and is
collected in the basin.
3. Stormwater flows from catch basin into the
system of stormwater pipes.
4. Stormwater flows through conveyance
system to the outfall. Miami Beach is now
moving to a system of pumps to more quickly
and effectively drain the water to the outfalls.
Each of these four steps requires an amount of time to accomplish, so no matter how a system is designed, draining an area of land can never
be instantaneous. Each of these four steps offers an opportunity for a bottleneck to develop and slow down the whole process. If the rain
falls at a faster rate than any one of the steps can accommodate, the system will back up and ponding (standing water) will occur.
For practicality and cost-effectiveness, new stormwater collection systems are designed to accommodate the runoff from a rain event of
a certain intensity and duration, called the design storm. Any rain event larger than the design storm will cause the system to back up. The
flatter the land, the slower the water will move, and the more time it will take to drain an area of land.
We are all in this together. Miami Beach has installed new stormwater systems and has elevated roads in many vulnerable areas in the city.
To learn more, visit www.mbrisingabove.com.
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