The Columbia Water Company collaborated with Buchart Horn Architects to modernize and expand the historic Walnut Street Water Treatment Plant in Columbia, PA. Originally constructed in 1849 and situated within the town’s Historic District and floodplain along the Susquehanna River, the plant required upgrades to meet increasing water demands and comply with state and federal regulations.

Over a three-year, multi-phase project, the plant’s treatment capacity was increased from 3.0 to 4.0 million gallons per day (MGD). The modernization preserved the integrity of the original structures while integrating new water treatment processes and technologies. Enhancements included flood protection measures, such as elevating critical equipment above the floodplain and constructing a reinforced flood wall to protect against ice floes. These improvements enhanced resilience, safety, and long-term service reliability for over 10,000 residents and businesses.

The project received the Diamond Award for Engineering Excellence – Water Resources from the American Council of Engineering Companies of Pennsylvania (ACEC/PA), recognizing its high degree of achievement, value, and innovation.

For more information on the project, please watch the following video: