In the past when heavy rains fell in Knoxville, drivers would regularly avoid Westland Drive, Prosser Road and Cross Park Drive.
Since the City invested in major stormwater infrastructure upgrades on those streets in 2013, that has happened only once — during what the National Weather Service called the wettest February since 1873.
In addition to a month of heavy rains, five inches of rain fell in just one day during February 2019, the biggest rainfall in more than 25 years. The torrential rains amounted to a 25-year storm over a 24-hour period.
Since 2013, the City has invested nearly $9 million in flood-control at the sites, including a stormwater drainage upgrade at Martin Luther King Jr. Avenue.
Engineering teams led with one goal in mind: Getting rain waters quickly and safely off the roads and properties. Year after year, for many years at these sites, flash flooding occurred regularly during heavy rains.
“Prosser Road would be underwater for weeks sometimes from heavy rains,” said Jim Hagerman, Knoxville Director of Engineering. “This happened multiple times a year for decades.”
Since completion of these major improvements, every one of these thoroughfares is functioning well, said Hagerman. “If the City does its job, the public isn’t impacted in most cases,” he said.
“Because of the challenges of some sites in the City, as we saw in February, we cannot always control flooding everywhere to the level we can on most streets. We can expect certain areas to flood once every five years or so, and February’s rains were an example of that. This is so much better than five times per year.”
These major flood-control project sites are complex infrastructure stormwater systems of drains and pipes and are dramatic improvements.
Specifically, the following mark the City’s biggest upgrades on four heavily used roads in recent years:
• Cross Park Drive: Located near I-40 and Cedar Bluff Road in West Knoxville, the $3.7 million drainage system was completed in 2015 and now handles a water flow of more than 280,000 gallons per minute.
• Prosser Road: The $1.4 million drainage improvements to reconstruct 1,600 linear feet of Prosser Road between Knoxville Zoo Drive and Magnolia Avenue was completed in 2014.
• Westland Drive: About 1,000 linear feet were reconstructed on Westland Drive west of Northshore Drive. The $2.2 million project was completed in 2015 included reconstruction of the drainage system under four driveways and the installation of a 14-by-7 box culvert that replaced an aging bridge.
• Martin Luther King Jr. Avenue: A $1.5 million stormwater drainage upgrade corrected periodic flooding between South Beaman Street and South Castle Street. The project was completed in 2013 and included new sidewalks and other infrastructure.
Today, Knoxville’s big flood risks of the past are a great reminder of how, through investment, the City has reduced flooding and improved safety throughout the entire community.
Additionally, the City completes smaller neighborhood flooding improvements every year. These preventive engineering projects total about $500,000 annually. The City also supports an annual emergency fund since 2017 for unpredictable issues.
“This is what happens when a city invests in stormwater infrastructure upgrades,” he said. “The entire community benefits – especially in terms of long-term safety.”
The opportunity for prevention is also built in to all City Streetscape Engineering projects, Hagerman said. “This amounts to full rebuilds underneath the streets. When completed, the streets “are good for another 100 years.”
“A streetscape project is a great opportunity to do a complete redesign of the infrastructure. The landscaping is just half of the work,” said Chris Howley, City Engineering Planning Chief. “Stormwater teams are able to assess the pipes underneath roads to be repaired. This helps us inspect and evaluate.”
During this past winter’s rains overall, Knoxville’s stormwater infrastructure was hard at work, moving water through the pipeline to prevent flash flooding in many areas of the City.
The overwhelming response from the community on the upgrades over the years remains positive. “On average, after a big storm, we now receive six complaints about localized flooding, compared to some 500 complaints many years ago,” Hagerman said.
“What I like to share and I think surprises people is that Knoxville sees about 50 inches of rainfall a year,” Hagerman said. “This is much more than Seattle, for instance, which has about 35 inches of rainfall. So far Knoxville continues to fare very well during our rains.”
Prosser Road, prior to improvements, in 2013
Prosser Road, after stormwater improvements