the download: debriefing the storm

Resiliency

Susan Askew
Susan Askew

the download: debriefing the storm:

what we know, what we learned

There’s a lot of emotion mixed in with the debris still left from this week’s storm. From anger to incredulity (WTF?) to “Come on folks, it was an intense rainfall, give the City a break”, social media lit up immediately. The City’s management team has done its debrief and here’s what we know…
 
Loyal readers know I rarely weigh in with opinion, though in this case I am wading into the waters (literally and figuratively this week). I’m sure it will make for some lively debate!
 
Sunny Day/King Tide Flooding versus Extreme Weather Events:
The City has completed about 15% of its new stormwater pump installation. The project, along with road elevation, is a key part of the efforts to combat the effects of sea level rise and the sunny day/King Tide floods we experience. These initiatives – which have been highlighted internationally and lauded at the recent U.S. Conference of Mayors meeting here – have probably raised our expectations about what these pumps can and cannot do. In a debrief Letter to Commission, City Manager Jimmy Morales emphasized the pumps are not designed to handle “the most extreme events”. To do so, he said, “would be very costly, rather unattractive due to the size of the necessary infrastructure and, as a seven square mile built-out island, the required infrastructure would adversely impact open space.”
 
This week’s rainfall was just such an event “with a rainfall rate of more than nine inches an hour and a total of six and one half inches from 2:00 pm to 5:00 pm,” he wrote. That is twice as much as the system can handle, “three inches an hour, hour after hour,” according to Morales. The City is prepared for the “high end” of the so-called five-year storm but that means “[The system] can handle seven inches in 24 hours, and the expectation and plan is that within 24 hours conditions are dry.” That said, “[A]t no point does the design guarantee that no flooding or ponding will occur during significant rain events. Rather the commitment is to drain the streets as quickly as possible thereafter.”
 
Duh. The pumps don’t work without power:
The old pumps are gravity based which do not require power but rising sea levels negate their ability to drain water effectively. The new pumps are part of a sophisticated system that cleans the water of debris and oil which ran directly into the Bay with the old system. They are part of a $500M Neighborhood Improvement Project plan to replace aging infrastructure – some of it 100 years old, crumbling and too small to handle the City’s needs today. The plan to upgrade the system while at the same time designing for sea level rise is a fairly new concept being pioneered by the City.
 
But…. as happened during Hurricane Matthew last year, some of the pumps lost power. In this case, five of the 15 new pump stations lost power for some period of time. “This explains the flooding at Lower North Bay Road, 14th street and 17th street,” Morales wrote to the Commission. “The pump stations in Sunset Harbour lost power for 45 minutes.” Sunset Harbour is the City’s lowest point and recently completed installation of pumps and a road elevation. While the streets in front of them are raised, many businesses in the area are below base flood elevation and experienced flooding on Tuesday. Morales emphasized the streets in Sunset Harbour “remained flood free despite [the power] outage, but some businesses which are below the base flood level were impacted.” Once the pumps regained power, the other areas below base flood elevation returned to normal within hours, some areas sooner.
 
Here’s the rub. While the pumps are not designed to handle intense rain, they do help clear the streets quickly. During sunny day flooding, which is their primary purpose, the power is not expected to go out so there was no backup power as part of the new system. Following the lessons of Matthew last year, the City Commission approved two permanent generators for Sunset Harbour. This week, however, Mayor Philip Levine issued a statement that the purchase “has been bogged down in bureaucratic paralysis” and he directed Staff to use emergency procurement procedures to make the purchase. In his Letter to Commission, Morales said during the negotiation process the City and selected vendor were “more than $200,000” apart on price. He said with the direction to expedite the purchases, the City expects a 90 day delivery and installation timeframe.
 
We think it’s fair to say Mother Nature doesn’t wait for procurement processes…
 
Going forward, Morales said Staff will present the Commission with “a plan for back-up generators citywide to include costs, size and neighborhood aesthetics and space considerations.” That last point is important. The proposed generators for Sunset Harbor are 5’ x 12’ x 6’, “elevated to 2’ above base flood elevation which is about 5’ above the street,” according to Morales.
 
Full disclosure here, in the adapt or retreat scenario, I am firmly in the adapt camp. I have no intention of abandoning Miami Beach. So, that said, if we want the pumps to work at clearing the flooding after an intense storm (and accompanying power outage), then we will have to figure out how to live as best we can with the infrastructure. [Cue the debate…]
 
In the meantime, Morales wrote, “The City has deployed portable generators to some of the pump stations, and more are being deployed to be on-site for faster startups in the event of further power outages. The smallest of these generators is about the size of a small truck and are located very close to the pump stations’ control center.”
 
But… Morales said, “In those neighborhoods where the pumps did not lose power (e.g. Crespi Boulevard, West Avenue), there was minimal impact from flooding.”  
 
The key, to state the obvious, is to keep the power on.
 
“Are the $500M pumps working?”
To clarify, the City has spent $100M, so far, and has completed 15% of a planned $500M project.
 
According to Morales and the team’s debrief: Sunset Harbour streets remained dry and when power was restored, the water was cleared quickly. In the areas where power remained on, there was minimal flooding and,  “In those areas where the city has yet to do any work (e.g. Flamingo Park neighborhood, Lower Bayshore), flooding was significant.”
 
Interfacing with private properties:
The City is still trying to assess and figure out how to interface with private property drainage. Regarding the flooding in Sunset Harbour this week, Morales wrote, “In at least some of these cases the flooding was exacerbated due to the private property roof drains emptying into the lower levels of the sidewalks. The City’s engineers and operation staff are working to identify ways to further improve system performance.”
 
Sunset Harbour is a heavily commercial area and the City does not yet have an example of a residential project. In response to resident concerns about road elevation and drainage, the City Commission earlier this year voted to allow homeowners to tie into the new stormwater system as their neighborhoods come online and their roads are raised.

About that traffic chaos:
As an observer of the City’s impressive operations during the King Tides of 2015 in which roads were strategically closed and police officers directed traffic to keep the City moving, it seems a similar plan is needed for emergencies. Flash floods can’t be planned for, but it seems we can plan for emergency response to close off problem areas quickly. Food for thought.
 
What’s next?
In addition to the City’s debrief on what it needs to do, here’s what residents and businesses can do to prepare and protect private properties:
 
First, recognize that we live on an island and 93% of buildings in Miami Beach are located in a FEMA special flood hazard area. Understand your flood risk by getting an elevation certificate and using the City’s tools to determine how road elevation will impact you.

Second, consider installing flood panels or vents or using sandbags when heavy rainfall is expected. The City’s Building Department offers free technical assistance (to residents and businesses) to identify ways to reduce flood hazards. Call 305-673-7610 to learn more.
 
While we accept sea level rise, it is important to note that one of the expected byproducts of that is more precipitation overall and potentially stronger storms. As John Englander writes in High Tide on Main Street, Rising Sea Level and the Coming Coastal Crisis, “In fact, a warming world will see a lot more moisture from a warmer ocean, causing significantly more precipitation overall.” And that will probably include more severe weather. “Though the correlation is not direct, most climate researchers believe that increased global temperatures cause a greater number of storms, including powerful hurricanes.”
 
If that is our future, we, and the City, need to be prepared for it.
 
Finally, don’t blame it on Emily:
According to the National Weather Service “[T]his weather event was not directly associated with Tropical Storm Emily, but [w]as part of the trough which extended across South Florida. This is the same trough that spawned Emily early Monday morning, July 31st in the northeastern Gulf of Mexico, which moved south to across South Florida, by Tuesday, August 1st.”

We stand corrected.
 

After the flood, part 2


Susan Askew
Susan Askew
pottery barn, williams sonoma closed; flamingo park loses ficus tree; convention center damage