'We can't protect it from large storms,' Johnson City stormwater official said rain caused clogged drains

Zach Vance • Updated Aug 13, 2018 at 10:45 PM

Torrential rains last Monday and Friday flooded the streets of downtown Johnson City, providing a familiar and unwelcoming sight to downtown business owners and visitors to the Little Chicago Festival. 

Once a common occurrence, flooding in downtown has largely been alleviated since the city completed its $30 million investment in flood mitigation measures and built Founders and King Commons parks. 

Nonetheless, downtown Johnson City was built on a floodplain next to King and Brush creeks, and when it rains hard during a short period of time, those creeks are going to flood.  

“Obviously, we can’t protect (downtown) from large storms, but we did improve it,” Andy Best, manager of the city’s Stormwater Management Division, said.

“(Consultants) were saying it improved from a two-year flood and up to a 5- to 10-year flood. So some of these, what I’ll call heavy storms, that we’ve had this season may have resulted in flooding previously.”

Both King Commons and Founders were designed to provide a place for water to go, directing it back into the city’s stormwater system, but sometimes even those parks can be overwhelmed, especially when drainage pipes get clogged. 

Best said city workers spent most of Tuesday last week cleaning all the drainage pipes and catch basins, following Monday’s storm, but when a large rain event occurs, like Friday’s, he said water will carry additional debris and clog up the drainage system. 

“I keep hearing clogged-up drains, and do realize that (the drains) were not clogged up prior to rain. So rain will tend to pick up debris and carry it to a drain. Whenever you see our guys trying to rake things off the top of the drain, usually it’s what the water has carried to it. That just happens during a large rainfall event,” Best said. 

Once again on Monday, Johnson City Public Works crews spent the day clearing drains and checking the underground system. 

Skillville co-owner Brad Cornelison said he saw crews on Monday pulling out a beach lounge chair and logs from the drainage system. 

“We’re spending most of the day (Monday)  to make sure everything is functioning, (and) going out and cleaning catch basins throughout the community, not just downtown. So we’re looking at all that,” Best said. 

Cornelison’s business, located at 224 W. Market St., was hit hard by Friday’s flood. He said about 2-to-3 inches of water poured inside his building, and many of his tools and wood got wet. Outside his building, he estimated water was about knee deep. 

“Nothing really got damaged, though, because of the concrete floor,” Cornelison said. 

He said it took 10 people roughly 2-to-3 hours to sweep and squeegee most of the water out, but moisture still remains.  

Best said the rainfall varied greatly around town. During Monday’s storm, he said his department recorded an inch of rainfall in 20 minutes. But at the Carver housing development on Washington Avenue, he said a contractor recorded 2.1 inches of rain in 15 minutes.  

“I think it was anywhere from a 10-(year) to 50-year storm, something like that. Again, it all depended on where you were at, how much rain you got and the time period,” Best said. 

Moving forward, Best said his department will be looking at ways to improve flood mitigation in downtown, which will include improving the slope on King Street to ensure water flows into the basin area easier. 

“We witnessed some things we’re going to kind of look at and model. We’re going to try and get some more water into the basin there beside the Johnson City Press (building). Once it gets on King Street, it’s hard to manage. So we want to try to put it back in our system that we’ve got built. So that’s our goal,” Best said. 

“We’re going to try to add some additional inlet capacity, just to get it into that catch basin area there.”  

When asked to estimate roughly how much the improvements might cost, Best predicted in the $20,000 range. 

To report a clogged drainage system, Best recommended the public call 423-975-2700. He also said the public can send photos to the city’s Public Works Department to help city officials model the rainfall and determine how the stormwater system performed. 




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