The Rivanna Water & Sewer Authority Rivanna Tunnel Project is located in Charlottesville, Virginia.  The project was design and constructed to help offset sewage overflow during heavy rainstorms.  The project includes the excavation for a new tunnel and building a new pump station that will sit on a site near RWSA’s Moores Creek Wastewater Treatment Plant.  The 1,600-foot long, 11-foot diameter tunnel will stretch from an area near Riverview Park in Charlottesville’s Woolen Mills neighborhood to the RWSA property.  The new 60-inch sewer pipe and the pump station have the capacity to move 53 million gallons per day.  The tunnel, which was excavated through solid rock, is located at approximately 60 feet below the surface for a large portion of its length, around 85 feet or more at its deepest levels and approximately 30 feet at the most shallow points.

Stiver Engineering provided the contractor with construction consulting through a support system for the 60″ diameter Hobas Pipe during the grouting phase of the 11 ft. diameter tunnel.  Stiver Engineering provides pipe buoyancy calculations and pipe support design for contractors throughout the United States.


Stiver Engineering provided the structural designs for a wastewater treatment facility in Zapata, Texas. The plant included headworks with pumping, filters, chemical addition, settling, mixing, high service pumping, chlorination, and storage.

Stiver Engineering participated in environmental engineering through the completion of the engineering and contract administration of the 10 MGD facility for the Washington Suburban Sanitary Commission in Washington, D.C. Improvements included rebuilding the trickling filters and the addition of sludge handling equipment. Sludge was incinerated using two fluidized bed furnaces, and additional effluent quality was achieved by the use of mechanical filters to remove those solids that might settle.

Stiver Engineering provided environmental engineering through design services for a new 1.0 MGD wastewater treatment facility in Nassau Bay, Texas, complete with a new sewer main, activated sludge treatment, secondary clarification, aerobic digestion, sludge belt presses, chlorination, de-chlorination, and filtration.  Because the facility was constructed within the floodplain, it was elevated to provide full protection from the rising flood waters of Clear Creek.

Stiver Engineering was recruited for environmental engineering through the civil, structural, electrical, control, and mechanical designs of the 22 MGD advanced wastewater facility in Friendswood, Texas. The processes involved included grit removal, primary clarification, activated sludge, secondary clarification, filtration, and more.