In Louisville, Rain, Flooding Are Clearest Signs Of Climate Change
Brenda Smith moved into her house in the Louisville neighborhood of Preston Park in 1973 with her husband and newborn son. A month later, her home flooded.
Smith and her family moved out, gutted the one-story home and rebuilt. She figured it was a freak event; a heavy rainstorm had filled a nearby ditch and sent the water streaming across her floor.
She lived there for another 24 years without incident. Then in 1997, Louisville got hit by a record storm. More than 10 inches of rain fell in the city. And Smith’s home — along with most of her neighborhood — was under 18 inches of water.
“We lost our car, we lost all of our furniture,” Smith said. “We had to replace all of the carpet, we had to remove walls. We bought new furniture, we had to buy clothes. It was a mess.”
Once again, the family moved out, rebuilt, and replaced everything.
“After that, we just figured the house wouldn’t flood again,” Smith said. “How often do you get 12 inches of rain? Not very often.”
Then they got hit again — in 2013. By now, the area had been designated as a flood plain, and the Smiths had flood insurance. Once again, they gutted the house and replaced everything.
“We had the money and we thought well, we’re really going to make this our home, you know?” Smith said.
And just as they were finishing up those extensive renovations, the house flooded once again in the spring of 2015.
And that was enough. Smith and her husband abandoned the home and moved away. The county’s Metropolitan Sewer District is in the process of buying them out.
But in Louisville, repeat flood events aren’t something that’s unique to the Smiths, or even to their neighborhood. All over the city, water is traveling in new ways and flooding new places. Some of this is due to development, impervious surfaces and poor planning. Some of it is due to aging infrastructure. And climate change contributes, too. These days in Louisville, rain storms are more intense and more frequent than they used to be.
‘A subtle loading of the dice’
The federal government has 145 years of rainfall data for Louisville. Over that time period, there have only been 11 years with two or more days of at least three inches of rainfall.
At that rate, you’d expect one of those heavy-rainfall years around every 13 years. But four of them have been since 1990. Of Louisville’s top 10 wettest years, half have occurred this century. Eight of the 10 have occurred since the 1990s, while none of the top 10 driest years have occurred since 1987.
Weather Channel meteorologist Jonathan Erdman said the increased frequency and intensity of rainfall in Louisville is directly linked to a warmer climate.
“In a warming climate we expect weather systems to being moving more slowly,” he said. And because the climate is warmer, we expect the atmosphere to be able to hold more water vapor.
"So, as a result, we expect weather systems to be able to produce a bit more rainfall and for there to be more heavy rain events than there would be if the climate was not warming.”
There are two different scenarios that tend to cause flooding here: one is extended wet periods that saturate the ground and raise the river levels. But the other is simply a large amount of rain in a very short period of time. That’s what’s led to some of the city’s recent flooding events, like in 2009 and 2015.
But it’s difficult to pin any single rain event on climate change.
“The insidious part of climate change, it is thought to be just a subtle loading of the dice as far as more intense heat, more intense rainfall events,” Erdman said.
So, maybe a two-inch rain event 50 years ago would be a two-and-a-half inch rain event today. But that half an inch could make all the difference.
River And Inland Flooding
When it comes to flooding in Louisville, the iconic images are from the devastating 1937 Ohio River flood. In January 1937, 15 inches of rain fell over the course of 12 days. The Ohio River crested at 85.4 feet at McAlpine Lock — about 30 feet higher than flood stage. About 70 percent of the city was submerged.
In the years following that flood, Louisville built an extensive flood protection system. Now, 29 miles of flood wall and earthen levee separates the city from the river, and 16 flood pumping stations sit waiting to be put into action.
One of the largest of those is the Beargrass Creek Pumping Station in Louisville’s Butchertown neighborhood.
There, eight pumps sit in a brick pump station built in 1952. If all the pumps are turned on, they can move more than 2.4 million gallons of water a minute.
“Anytime we have a rain event — it could be a tenth of an inch of rain — it could affect us based on how we’re going to manage the system,” said MSD Flood Protection Supervisor Dane Anderson.
If the Ohio River is rising, it might call for closing the system’s nearly 150 floodgates and installing 80 floodwall street closures. But even when the river’s not rising, pumps are often deployed to move excess water into streams that then exit into the Ohio.
“It’s quite frequently, every year we have two or three events that we have to manage some of these stations,” Anderson said. “In a sense we’re a big insurance policy that makes sure this city is not flooded.”
But aside from the flooding that comes along the rivers and streams, Louisville is dealing with an increasing drainage problem. That’s what devastated Brenda Smith’s house — not once, but four times.
And in some areas, newer development has played a role.
Dionne Franklin’s family has owned property in Prospect, Kentucky, — right outside Louisville — since the 1970s. The neighborhood known as the Taylor Community was established as an African-American neighborhood in the 1920s. Until recently, the community was surrounded by farmland.
“All of that open land is now concreted over with road, or houses with roofs,” Franklin said. “Most of it is no longer open anymore.”
And that’s forced rain into new areas. Specifically, onto Franklin’s family property. After 30 years without incident, what used to be the house’s yard has turned into new marshland, and the repeated flooding has forced the Franklin family to abandon the property.
MSD Director Tony Parrott said the county has a number of subdivisions dealing with similar issues. He said with the increase in extreme storm events, “the designs of those systems were not anticipating what we’re seeing today.”
Simply put, there’s just too much water. And Louisville has scant resources to invest in the infrastructure needed to manage it.
Multiple Problems, Stretched Resources
For Louisville’s Metropolitan Sewer District, this increased rainfall causes some serious infrastructure challenges. The system is taxed — everything from the flood protection system protecting the city from the Ohio River to the inland drainage system meant to move water away from low-lying areas within Jefferson County.
And doing all that is complicated by the fact that the city is already sinking millions of dollars — $850 million, to be exact — in a federal consent decree to reduce the amount of sewage the city routinely releases into the Ohio River and its tributaries.
In the older parts of the city, it only takes one-tenth of an inch of rain in an hour to trigger a combined sewer overflow — where the water treatment plant can’t handle the volume of liquid it’s getting, and so a mix of rainwater and diluted sewage is released into places like Beargrass Creek and the Ohio River.
This is a problem for other cities in the region — including Cincinnati and St. Louis — and Louisville is slightly more than halfway through the consent decree. It’s scheduled to be completed by 2024. But in the meantime, it’s sucking money out of MSD’s budget, and other flooding and drainage issues are going unaddressed.
One of the casualties is Project DRI — which stands for “Drainage Reduction Initiative.” MSD dedicated millions toward solving neighborhood drainage issues. As recently as Fiscal Year 2016, about $22 million went toward the program. That allocation has since been cut drastically.
“Now because of where our budget is and because we’ve been so focused on dealing with the consent decree, we’re only allocating about 2 million to our DRI program,” Parrott said. “And that is just not enough to address all of the drainage issues we’re seeing throughout Jefferson County.”
And those drainage issues are costing money after the fact. Putting aside the money it takes to fix infrastructure once it’s failed, the Federal Emergency Management Agency has paid out more than $35 million in flood insurance claims to Louisville properties since 2000.
Some — like Brenda Smith’s home in Preston Park — have flooded multiple times over very short periods of time.
MSD has spent two years making the case for Louisville to invest more money in drainage and flood protection infrastructure. Parrott estimates it’ll take an additional $4.3 billion over the next 20 years to address the numerous challenges.
But that will require more money from ratepayers. And for two years, the steep rate hike MSD needs to make this plan a reality hasn’t gained traction with local lawmakers.
So for now, the city is moving ahead with Band-Aid repairs to infrastructure, addressing cave-ins and localized flooding as it happens. But the intense rain events continue. And climate models predict as carbon dioxide emissions continue to increase, the downpours will, too.
And for Louisville, it’s not a question of whether there will be another damaging flood that damages property in some of the city’s low-lying areas. It’s a question of when.
This story was produced in partnership with Weather.com's United States of Climate Change project.