Equalization Stations
What are EQ Stations?
When there is not enough storage capacity in an area of the City to handle the high volume of stormwater entering the wastewater system during heavy rain, the solution is to build wet-weather storage facilities, or “Equalization (EQ) Stations”. EQ stations create capacity, help equalize the flow through the system, and, as such, prevent sanitary sewer overflows.
How do these EQ Stations operate?
When the system gets full during a storm event, excess wastewater and stormwater will be diverted to a wet-weather pump station and get pumped into the EQ tank. The EQ station will temporarily store this water until the system has the capacity to handle it. These facilities are generally emptied within 48 hours after the storm has passed. The water makes its way to the Moccasin Bend Environmental Campus to be properly treated.
These EQ stations do not cause any smell. The facility features enclosed construction with integrated odor control systems. Air is vented into a pipe and sent through a carbon filtration system before being released into the atmosphere.
Operations of an EQ Station
Inside an EQ Station
Many factors go into selecting the site for an EQ Station
– Site receiving the most public acceptance following community meeting(s)
– Preferably in industrial or commercial area vs. residential
– Proximity to the Sanitary Sewer Overflow locations it needs to address
– Proximity to the main sewer interceptor
– Not in a Flood Zone
– Terrain suitable for construction
Mayor Tim Kelly Inaugurating the Hamm Road EQ Station (2022)
Where are these EQ Stations located?
As part of the Clear Chattanooga program, EQ stations are being constructed at 4 different locations of the City.
1. The Hamm Rd EQ Station was inaugurated by Mayor Kelly in 2022. The facility includes three 10-million-gallon EQ tanks, providing an overall 30 million gallons of storage capacity during wet weather, and has stored almost 1 billion gallons of water to date. The facility is strategically located immediately upstream of the Moccasin Bend Environmental Campus and has helped to prevent major overflows into the Tennessee River.
2. The Kanasita Drive EQ Station was completed in Hixson in 2026 and provides storage capacity of up to 5 million gallons of wastewater during significant rain events. The EQ station will help prevent sanitary sewer overflows along Adams Rd, Hamill Rd, Crescent Club Dr, and Longview Dr. A new pump station was also constructed on this site to replace the previous one on Adams Road, which was demolished. Finally, new sewer pipes redirect flow between the old and the new sites.
3. Everyone has been wondering what is being built along I-75. Those are two 15-million-gallon EQ tanks under construction as part of the Environmental and Economic Infrastructure Improvements (e2i2) Plan. This EQ station is built as part of an interlocal agreement (cost sharing) between the City of Chattanooga and the Hamilton County Water and Wastewater Treatment Authority (HCWWTA) and will provide 30 million gallons of storage when completed in March 2027.
4. A 10-million-gallon EQ station is also under construction along Lee Hwy as part of the same e2i2 Plan.
