The Integrated Pipeline is a joint water supply project between Dallas Water Utilities and Tarrant Regional Water District. It involves building 150 miles of pipeline to transport up to 350 million gallons water daily from three East Texas Reservoirs into the Metroplex to increase reliable water access. The project recently reached a new milestone when the new tunnel under Trinity River was completed. Workers are now beginning to add 50‐foot sections of 108‐inch diameter steel pipe.

Stiver Engineering performed full design work for the IPL tunnel. The design/build project scope included construction of approximately 3,802 linear feet of 108‐inch water line including 2,614 linear feet of tunnel under the Trinity River and the remainder in deep open cut segments along the proposed alignment of Section 17.

Other aspects include tunnel launch and retrieval portals/shafts, deep open cut approach ramps with temporary shoring at approximately 12:1 slope, pipe laying within approach ramps and tunnel initial support, pipe encasement with flowable fill and reinforced concrete, tunnel grouting, a 15.6‐foot diameter custom designed tunnel boring machine, and precast segmental tunnel lining.

The Mill Creek Drainage Relief Tunnel is a construction project that will bring needed infrastructure improvement to east Dallas, Texas. Stiver Engineering provided construction consulting services for the contractor prior to and during the tunnel construction.

The tunnel, which stretches from the State-Thomas District in Uptown Dallas, through Mill Creek and Peaks Branch, will be constructed mostly underground with little impact to neighborhoods. Once complete, the approximately five mile-long tunnel will sit 70 to 100 feet below ground to provide flood relief.

The Mill Creek Drainage Relief Tunnel is a five-mile underground tunnel that will provide 100-year flood protection for nearly 6,000 commercial and residential properties in the east Dallas area, including Baylor Medical Center. The current drainage system in these areas was constructed 50 to 70 years ago, and only provides a two to five year flood protection. Major flooding that occurred in 1995, 2003, 2006 and 2009 crippled these areas and showed dire need for the construction of this drainage relief tunnel. The Mill Creek/Peaks Branch/State-Thomas Drainage Relief Tunnel will improve stormwater management resulting in saved lives, protection of schools, medical facilities, residents and streets. Construction began in spring 2018 and is slated for completion in 2023. The tunnel is being constructed by Southland Mole Joint Venture. Prior to construction beginning, a tunnel-boring machine (TBM) will be constructed on site. By using a TBM, there will be minimal utility relocation, as well as minimal street and traffic impacts. Once complete, the tunnel will be approximately 30 feet in diameter, and will be designed to carry a maximum flow of nine million gallons per minute. This provides exponential relief of flooding during large rain events. The tunnel will have six intake sites along the alignment. These include:

  • Woodall Rodgers Intake – Intersection of Woodall Rodgers Freeway and Maple-Routh Connection
  • Mill Creek Intake – Intersection of San Jacinto Street and Apple Street
  • Peaks Branch Intake – Intersection of North Carroll Avenue and Victor Street
  • Peaks Branch 2 Intake – Intersection of E R L Thornton Freeway (I-30) and South Hill Avenue
  • East Peaks Branch Intake – Intersection of Bank Street and Herndon Drive
  • Outfall – White Rock Creek at Barber Avenue

 

The City of Houston’s Northeast Water Purification Plant (NEWPP) Expansion Project is a design-build project that will add 320 million gallons per day (mgd) by 2024 to the existing water plant’s capacity. The expansion project will allow the City and the regional water authorities to meet projected demands, while fulfilling requirements set by the Harris-Galveston and Fort Bend Subsidence Districts resulting in a shift from historical groundwater usage to a predominant reliance on surface water.

​Construction on the $1.7 billion project started in early 2018 and has been called the largest expansion project in the world. The NEWPP expansion is required to comply with subsidence district rules for conversion from groundwater to surface water supply, resulting in a reduction of the subsidence rate.  Features of the project include the design, construction and commissioning of:

  • Intake pump station
  • Twin 108-inch transmission mains
  • Pre- and post-treatment chemical addition
  • Flocculation/sedimentation basins
  • Ozone treatment
  • Filtration
  • Finished water storage tanks
  • High service pumping station

Stiver Engineering provided construction consulting through the following designs for contractors working on the NEWPP Project:

  • Shoring design for 10,200 LF of twin 108-in.-dia. raw water transmission mains in common trench at a depth of 18 ft. to 40 ft.
  • Pipe buoyancy calculations for the 38,000 CY of controlled low strength material (CLSM) backfill.
  • Entry shaft, exit shaft and tunnel design for the 360-LF, 132-in.-dia. tunnel using liner plate.
  • Shoring design for the filter/transfer pump station.

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.

 

The $142 million Schoharie Reservoir Project in Gilboa, New York – which is expected to be complete in the year 2020 – includes the construction of an intake structure at the bottom of Schoharie Reservoir, more than 2,000 feet of subsurface tunnels, and a valve chamber along Schoharie Creek. Once completed, the tunnel and valves will provide New York City’s Department of Environmental Protection with the capability to release water from the reservoir into Schoharie Creek to facilitate dam maintenance, respond to potential emergencies, mitigate flood risk for downstream communities, and enhance downstream habitats for fish and wildlife.

Continue reading “New York Environmental Protection Bureau of Engineering Design & Construction”