The Omohundro Water Treatment Plant (OMO WTP) in Davidson County, Nashville, Tennessee is a large municipal facility situated on a constrained 200 acre site bounded by the Cumberland River, Lebanon Pike, an active railroad corridor, and adjacent commercial development. The plant is currently undergoing a major expansion to increase its treatment capacity to 150 MGD. Existing site limitations include an active commuter rail line crossing the property, high voltage TVA transmission lines, and an onsite stream discharging to the Cumberland River. To support the expansion, significant utility infrastructure and the onsite stream required relocation to create space for new treatment facilities. The required yard piping involved six crossings beneath an active R.J. Corman owned commuter rail line, along with the construction of four new raw water intakes along the river. Due to uninterrupted rail operations and environmental constraints, all crossings and intakes were completed using trenchless construction methods. The trenchless work was executed using large diameter microtunneling, with casing diameters ranging from 72 to 84 inches. Sunken caisson shafts were advanced into bedrock to serve as launch and receiving shafts, including a primary shaft approximately 80 feet in diameter and 50 feet deep constructed within a heavily constrained portion of the site. Two of the raw water intakes were installed using wet retrieval methods within the Cumberland River, requiring detailed coordination of hydraulic, geotechnical, and environmental considerations. This presentation will describe the design approach, construction methods, and risk management strategies used to successfully deliver large diameter microtunneled crossings in an active, environmentally sensitive, and operational water treatment facility. Key challenges encountered during design and construction and the solutions implemented will be discussed to provide practical lessons applicable to similar utility and water infrastructure projects.