Jollyville Transmission Main

Small World Map

Location

Austin, Texas, USA

Scope of Supply

1 x 3.0 m (9.8 ft) Double Shield TBM, 1 x 3.25 m (10.7 ft) Main Beam TBM

Tunnel Length

2.8 km (1.8 mi), 6.1 km (3.8 mi)

Ground Condition

Karstic Limestone and Dolomite

 

Texan TBMs Will Tunnel Below Scenic Canyons

  • TBMs will excavate beneath the Balcones Canyonlands, a protected wildlife area
  • Karst formations cannot be grouted because they contain endangered cave-dwelling invertebrates
  • In 2014 the transmission main will carry up to 190 million liters (50 million gallons) of water daily to the Jollyville Reservoir