Nashville Metro Water Services


Nashville, TN


Civil Engineering, Structural Engineering, Water Engineering, Mechanical, Electrical, Plumbing (MEP)

Water, water, everywhere but not a drop to drink! So goes the Rime of the Ancient Mariner, and so it was with K.R. Harrington Water Treatment plant. One of two water treatment plants that provide potable water to metropolitan Nashville and Davidson County, the 90-MGD facility was engulfed by the 2010 Nashville flood, taking the plant offline, and damaging major equipment such as the electrical switchgear that powered the plant’s diesel generators.

Prior to the flood event, Gresham Smith was selected to design the replacement of the plant’s existing switchgear. But this natural disaster made us quickly switch gears, changing the project’s scope to a major flood-protection effort. Our design solution delivered a flood-protected, earthquake-fortified, energy-efficient water treatment plant that provides the city of Nashville and Davidson County with a safe and reliable source of drinking water.

story electrical building
feet above the flood record
switchgear replaced
Side view of new electrical building featuring the exterior stair at K.R. Harrington Water Treatment Plant

Protecting to Serve

To ensure the facility wouldn’t fail under another flood, we were tasked with fully protecting the entire plant’s electrical supply and distribution system from a 500-year flood event in addition to replacing the original, deteriorating switchgear. To replace the plant’s 4,160-volt main switchgear and at the same time keep the facility operational required the installation of a new electrical building on the site.

Upgraded diesel generators at K.R. Harrington Water Treatment Plant

Rising Above

We designed the two-story electrical building to stand 2 feet above the 500-year flood elevation. The first floor houses four upgraded diesel generators relocated from the existing electrical building, one new generator and space for a future generator. The upgraded switchgear and variable frequency drives (VFDs) are situated on the second floor. In addition to being flood-resistant, the structural steel building was designed to be earthquake-resilient to meet stringent International Building Code requirements.

Electrical systems at K.R. Harrington Water Treatment Plant

Built-in Backup

To increase reliability, we designed redundancy into the various electrical systems. The upgraded diesel generators transferred from the existing electrical building can produce enough power to operate the entire plant at the rated 90-MGD capacity, providing a standby electrical power source for the entire plant. We increased energy efficiency by installing 4160-volt VFDs on the high service pumps to vary treatment system flow rates to match the water distribution system demands.

View of new electrical building from a distance featuring storage tanks at K.R. Harrington Water Treatment Plant

Never Missing a Beat!

Gresham Smith engineers replaced K.R. Harrington’s entire electrical system—from switchgear and cables to instrumentation and controls—without shutting the plant down. As a result of the complex project, the Nashville metropolitan area and its surrounding communities now have a more weatherproof 90-MGD water treatment plant.