Greenville’s “Big Dig”: How Dig Greenville Changed the Game
In March 2018, Renewable Water Resources (ReWa) launched one of Greenville’s most ambitious infrastructure projects: the Dig Greenville (Reedy River Basin Sewer Tunnel). Designed to expand wastewater capacity, protect water quality, and reduce sewer overflows, this multi-year undertaking created a new deep-bore conveyance system beneath downtown. The project was led by contractor Super Excavators / CMCRA JV with Black & Veatch as design and construction manager, and supported throughout by H&M Surveying as the construction surveyor.
Engineering Precision Beneath the City
At the heart of the project was a 1.1-mile long, 11-foot diameter tunnel excavated roughly 100 feet underground. Inside that tunnel, a 7-foot diameter fiberglass carrier pipe was installed to carry wastewater safely and efficiently. The system was designed to reduce overflow into the Reedy River, support Greenville’s rapid growth, and provide capacity for the next century of development.
Before the tunnel boring machine (TBM) could advance, crews had to excavate nearly 240 feet of mixed clay and rock by hand-dug methods and drill-and-blast techniques. This starter tunnel demanded extreme accuracy, as even minor deviations could have compromised the alignment. H&M Surveying established control points, verified shaft and tunnel geometry, and provided the layout data Super Excavators needed to launch the TBM precisely.
As-Built Verification Inside the Tunnel
When the fiberglass carrier pipe was installed, H&M Surveying conducted full as-built measurements to confirm its alignment and position. Survey crews entered the tunnel and performed traditional surveying from within the pipe itself, traversing the entire 1.1-mile length underground. Using high-precision instruments and established control points, the survey team documented the pipe’s horizontal and vertical alignment, ensuring it matched design tolerances and engineering specifications.
This step was critical: accurate as-builts not only verified the pipe was installed correctly, but also provided ReWa with permanent records for future inspection, maintenance, and expansion. Without these measurements, long-term confidence in the system’s reliability would have been impossible.
Accuracy That Made the Difference
Throughout the project, H&M Surveying’s expertise in tunnel and utility surveying was a cornerstone of success. Their work gave contractors and engineers the confidence that excavation, boring, and pipe installation were all executed within precise tolerances. The ability to combine advanced technology with traditional field surveying methods, sometimes in challenging, confined underground conditions, ensured every phase of the Dig Greenville project was delivered to exacting standards.
Community Impact & Recognition
By 2021, the tunnel was placed into operation, adding critical wastewater capacity and protecting Greenville’s waterways. The project minimized the risk of sewer overflows into the Reedy River, supported ongoing development, and modernized infrastructure for decades to come.
The precision delivered by Super Excavators and H&M Surveying helped ReWa earn national recognition, including a National Environmental Achievement Award in 2023 for its operational and environmental impact.
Why It Matters
The Greenville Big Dig was more than a tunnel, it was a partnership of engineering, construction, and surveying expertise that solved one of the city’s most pressing infrastructure challenges. From initial layout to final as-built, H&M Surveying’s role as construction surveyor ensured accuracy every step of the way, including walking the full 1.1-mile underground pipe to confirm its exact placement. The result: a project completed with the precision, safety, and reliability Greenville can count on for the next century.
