Nashville’s largest reservoir is a man-made, stone, dual-chambered tank that quietly overlooks the heart of downtown Nashville. One of the best views of the skyline is from the historic gatehouse atop the walls of the reservoir. The reservoir sits over 200 feet above the Music City Center and supplied the city with 51 million gallons of drinking water from 1889 – 2004. The west chamber was taken offline in 2004 and for almost 20 years, downtown Nashville relied on the eastern 25 million tank for their drinking water and fire suppression supply. This reservoir is very precious to the residents of Nashville and its historic restoration and functional rehabilitation became a paramount concern for Nashville’s Metro Water Services. In 2015, Metro Water Services decided to design and build a dual-chambered, 35-million-gallon, baffled, drinking water storage tank within the walls of the historic reservoir. HDR Engineering completed the design for the new tank and in the spring of 2023, the 1st phase of construction was completed. Bowen Engineering constructed a 15 million gallon concrete tank in the western half of the 8th Avenue Reservoir which meant that the City of Nashville was able to take the eastern chamber of the 134 year old reservoir offline for the final time. In 1912 the wall of the eastern half of the reservoir wall failed and caused an immense amount of property damage. Taking the old reservoir offline for the final time was a tremendous accomplishment for the city as the risk of a repeated flooding catastrophe was eliminated. The 2nd phase of construction is well underway and consists of the construction of a 20 million gallon, baffled, concrete, drinking water tank in the eastern half of the historic walls. This tank will merge into the tank from the 1st phase to provide 35 million gallons of storage capacity for the city. Metro Water Services elected to keep the flexibility of operating the tanks independently from one another. This will allow for un-interpreted service to our customers and the ability to take either half of the tank offline for inspections or maintenance. Phase 2 also included the demolition and reuse of the dividing wall in the 8th Avenue Reservoir. This wall separated the eastern and western chambers and originally acted as a weir to filter the settled solids from the drinking water. The construction of the Phase 2 tank is scheduled to be completed early in 2025. This presentation will continue the journey that was initiated at ACE in 2023. The audience will learn about the lessons-learned in the 1st Phase of the project, and the construction of the larger half of the tank-within-a-tank project. Additionally, the presentation will illuminate the audience to the Phase 3 designs and sustainability initiatives. Phase 3 consists of the design of a new entry building to the gatehouse, the historic restoration of the gatehouse, and the site beautification to preserve this gem for Nashville and the generations to come.