BCRUA Deep Water Intake Project, Phase 2
Growing populations plus prolonged drought conditions threatened reliable water supply for three Texas cities, Cedar Park, Leander, and Round Rock. They formed a partnership, Brushy Creek Regional Utility Authority (BCRUA), and developed a project to access, treat, and deliver water from Lake Travis to their customers. Phase 2 consists of a deep-water intake source at the lake, and Schnabel is the lead designer for the tunnels, shafts, and suction chamber.
Brushy Creek Regional Utility Authority (BCRUA) is developing the new system to ensure their fast-growing jurisdictions have an adequate and reliable supply of water. Project components of the second phase include the raw water intake, a gravity intake tunnel, a maintenance facility, a pump station, and a transmission tunnel. The intake consists of two lake-tap risers that connect to the gravity intake tunnel, which will convey water from the lake taps to the pump station. The 9,000-foot-long intake tunnel has a 10-foot excavated diameter and concrete liner at depths of 100–400 feet.
The pump station will have an ultimate capacity of 145 million gallons per day with up to 10 pumps. It incorporates a 300-foot-deep wet well shaft that connects to an underground suction chamber with six well shafts. Another shaft connects the pump station to the transmission tunnel. The transmission tunnel is 2,600 feet long, with an excavated diameter of 10 feet and a steel liner. It connects to an existing transmission main via a retrieval shaft on the other side of the lake. The maintenance facility comprises a building and a chemical feed pipeline. The latter, which was installed via horizontal directional drilling, connects to the lake taps.
Along with the general design of the tunnels, shafts, and suction chamber, we are also providing support for constructability assessments, cost estimating, and geotechnical investigations and recommendations for the pump station and maintenance buildings. We are now also responsible for developing and executing the project risk management plan, which involves qualitative risk analyses and updating the project risk register to identify, characterize, and mitigate potential risks to the project. The plan also includes a probabilistic quantitative analysis of cost impacts of risk events to aid in the establishment of the construction contingency.