Today, the Army Corps of Engineers will testify before Congress on its performance during the historic flood. As I pointed out in this series, the Corps did not apply the lessons learned from the 1975 flood, and its structural problems limited their response. The hearing should help start correcting these problems.
On its website, the Corps says that one of its top missions is "to reduce risks from disasters." There are two ways to do that: by preparing us before a record rainfall and by warning us before the river rises to dangerous levels. Did the Corps prepare us or warn us?
Here's what happened before the flood:
The Corps uses misleading words like 100-year, or 500-year, to describe rare events, often causing people to underestimate risk. Those adjectives do not mean you are safe for 100 years, or that you only face a 1 percent risk of flooding.
Almost no one in low-lying areas of Nashville knew there was a 26 percent chance of serious, 100-year flooding during their
30-year mortgage. Dig deep into the Corps website and you'll find it: Roughly 1 percent risk every year in a 100-year flood plain, and the risk adds up. Too few Nashvillians knew that they needed flood insurance to cope with a 26 percent risk.
There are 11,496 at-risk residential and business properties in Davidson County inside the floodway and 100-year flood plain, but only about 3,895 had flood insurance. In other words, only about one-third of those who needed insurance coverage had it.
The Corps also does a poor job of teaching us that living near a river gets riskier every year in fast-growing regions. Every new parking lot and building changes the way that rainfall reaches rivers. Homes and businesses that are safe now may not be in the next decade, so everyone needs a margin of safety.
Here's what happened during the flood:
According to the press conference that the Corps and the National Weather Service held in Nashville after the flood, "The Corps is not a 24/7 water management operation."
The weather service was, during the flood, "basically, if you want to call it, running blind."
The Corps increased the flow from Old Hickory Dam 22 times on the crucial day, Sunday, May 2, but only updated the National Weather Service four times, probably preventing the weather service from making accurate forecasts.
The Cumberland River rose 19 feet in 16 hours that Sunday, exclusively because of releases from Old Hickory Dam, which tripled that day to reach an all-time record.
Hardly anyone downstream knew that Old Hickory Dam was releasing more water than it ever had before.
In a sense, it no longer was acting as a dam, because it was releasing everything it could.
Lives were lost and hundreds of millions of dollars of damage were done to vehicles, inventory and movable equipment simply because we lacked even a few hours warning of these massive Cumberland River flows.
The Corps has never publicly volunteered that it has a "what if" computer program that judges whether it could have run our dams better.
It's like playing chess against a computer.
Will the Corps disclose at today's hearing how its performance scored? Nashville deserves to know if our dams could have been managed better.