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 DigIndy Project is a nearly 28-mile long network of 18 foot diameter deep rock tunnels being built 250-feet beneath the city.  Beginning near the Indiana State Fairgrounds on the north, and ending on the south side of Indianapolis, DigIndy will be the largest public works project in the city’s history.

The tunnel system will extend along Fall Creek, White River, Pogues Run, Pleasant Run and Bean Creek to create a collective, underground storage and transport facility for wastewater.  All sewage stored and transported in the tunnel system is sewage that otherwise could have gone directly into local waterways. The tunnel system is a component of the federally-mandated plan to reduce raw sewage overflows into the waterways.

The Indianapolis Deep Rock Tunnel Connector Pump Station Project included a screening and grit removal system consisting of 180 feet of 6 foot diameter connector tunnel, a subterranean pump room that is 60 feet wide by 98 feet long by 66 feet tall, a 44 foot diameter main access shaft with an enclosed elevator, enclosed stairway and various utility systems.  The subterranean pump room is located 250 feet below ground surface.  The project also includes a 23 foot diameter equipment shaft with embedded electrical conduits, an at grade pump station building, an at grade main access shaft building, an at grade discharge chamber and miscellaneous site work.

Stiver Engineering was retained for construction consulting by the contractor to design thrust blocks and pipe supports for the intake piping, miscellaneous piping running up the 250 foot access shaft walls and piping for the discharge chamber.  Stiver Engineering designed the permanent dewatering system for the large subterranean pump room 250 feet below the surface.  We also assisted in the design of a mobile concrete forming system for the construction of the 6 foot diameter connector tunnel.

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.

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