__Update: NOAA upgraded the storm to a class 1 hurricane at around 2 pm ET on September 1, as sustained wind speeds increased to near 75 mph. The storm is expected to make landfall on Florida's Gulf Coast at around 2am on September 2. __
Someday, the seas will rise and Florida will drown. But does Florida—facing oblivion by climate change, looked upon with pity by the rest of the country, the subject of torrential tongue-clicking chronicles of its death foretold—give up? No. When a tropical storm like Hermine threatens inundation, Florida says not today.
The southern state's geography is especially flat and especially moist. Add rain to those superlatives and you get flooding. So Florida's general water management strategy is to subtract. The specifics vary from district to district, but all depend on precise meteorological forecasts of when and where the rain will fall. But they can't just use locks and dams to let the stuff systematically run off to the ocean. For one—surprise!—swaths of Florida are rural, and don't have storm water management. For two, faced with a high tide or big storm surge, letting the water run off might not even be possible. And for three, this is Florida: Sometimes things gets too crazy for anyone to handle.
According the the National Weather Service's latest forecast, Hermine will likely make landfall somewhere along the Gulf Coast armpit connecting Florida's panhandle to its dangling peninsula. This is in Suwannee River Water Management District's jurisdiction. It is about the same size as New Jersey, and its biggest city is Lake City, population 12,046. "We do not have flood control structures, not dams or canals," says Abby Johnson, the water district spokesperson. Rain falling here trickles into rivers, and then to sea. Rather than control the flow, the district's hydrologists watch inundation levels, and issue warnings—or evacuations—as needed.
Which is exactly what the Suwannee River WMD started doing following the state of emergency Florida governor Rick Scott issued yesterday. Public boat launches, beaches, and public parks are off limits. Schools are closed in three counties. And nearly a dozen communities got partial evacuations.
Other places in the state are able to be more proactive. "As far as a flood control system, there's really not another like ours," says Randy Smith, spokesman for the South Florida WMD. "OK, maybe the Netherlands." South Florida, home to more than 8 million people, was built atop a swamp. "We have 2,000 miles of constructed canals, connected through local drainage for cities and counties," says Randy Smith, spokesperson for the South Florida WMD. Some of this flood control infrastructure dates back 100 years or more. "This is what was used to drain the swamps and made it possible for people to live here," says Smith.
The district has a central computer that controls a network of floodgates, reservoirs, weirs, locks, and culverts. Gauges distributed throughout the system feed water level data back to the control room. When a storm approaches, the district's meteorologists get to work. "They’ll take areas where rain is forecast and give that information to the water managers, who program the system to start drawing water levels in canals down ahead of time, in relation to how much water we’re able to receive," says Smith.
But you can't just empty it all out. That might cause some areas to accidentally flood, or dry out. "We don’t drain the canals to where there’s no water whatsoever because you would probably collapse the structures," says Smith. Also, you need some of that water to stick around and trickle into the aquifer. Because, drinking.
Florida is relatively flat. Even so, the South Florida WMD's drainage—which runs from west to east—is powered by gravity. Unless the ocean won't let it. Typically, the district will simply close the flood gates. These are steel structures about 25 to 30 feet tall that span the breadth of each canal's ocean outflow. But if inland rainfall gets to be too much, and threatens to overflow the canal's banks, the water managers start turning on the pumps. The agency owns 70 diesel powered impellers, some strong enough to discharge up to 3 inches worth of rainfall in an hour.
In terms of technological control, Sewannee River and South Florida WMDs are at opposite ends of flood management. Each of Florida's other three other water management districts has infrastructure assets and management plans that lie somewhere between. What do they have in common? Stubborn resistance to the destiny lapping away at their shores. Not today.
