Walhalla Water Treatment Plant

Walhalla, SC

City of Walhalla
Delivery Method
CM At-Risk

Project Description

The City of Walhalla chose GMC as the design team and Harper as its CM At-Risk partner for their 4MGD Greenfield water treatment plant and associated raw water intake and high service pump station. Harper worked with the City and GMC for 4 years to design a plant that met the City’s needs and budget, negotiating the budget and project design into 17 iterations with multiple cost savings options.

Budget was a significant concern for the owner. To enable the project to move forward, Harper and GMC continuously revised the design and actively sought the best value engineering options throughout design and preconstruction. The result was a best-value project that allows the City to produce their own drinking water. The treatment process uses Super P/Greenleaf filtration, backwash lagoons, and sludge drying beds.

The administration building houses a laboratory and chemical feed systems. The raw water intake pump station on Lake Keowee includes a 30’+ deep cast-in-place concrete drywell below the lake level, passive intake screens, 20’ tall retaining wall, new pump station building, generator, suction lift pumps, and significant groundwater and bedrock management activities on a difficult to access site.


  • Our team worked with the City of Walhalla over a 4 year period to understand their needs and capture their wishes. The end product was a plant that is easy to maintain and gives the City of Walhalla independence from surrounding municipalities by allowing it to provide its own water.
  • 2021 Carolinas AGC Pinnacle Award