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Design and Construction of WTP4

Water Treatment Plant 4 (WTP4) is currently under construction in northwest Austin; this multi-faceted construction project includes an intake system in Lake Travis, a raw water tunnel and pump station, the treatment plant, and the Jollyville transmission main, a large underground pipeline connecting WTP4 to the Jollyville Reservoir for distribution. Initially, WTP4 will be capable of treating 50 million gallon a day (mgd) capacity with room to expand to 300 mgd. Currently, this project is on schedule and within budget.

Raw Water Intake System and Pump Station

The water's journey from lake to distribution starts at the raw water intake structure under construction at Lake Travis itself near the Oasis restaurant. Fully submerged in the deepest part of the lake (at full lake level), it will be a series of three stainless steel mesh filters and screens that remove large debris. Buoys will be installed at the perimeter of the intake area to prevent boaters and swimmers from accessing the area. Raw water will travel from the intake system via 9-foot tunnel to a raw water pump station, whch will distribute water to the raw water transmission main, which then goes to the treatment plant.

As of Fall 2011, the raw water intake system is under construction at Lake Travis. The raw water tunnel access shaft has been excavated to 350 feet, and tunneling continues from the raw water pump station to the treatment plant.

Water Treatment Plant 

Once the water reaches the treatment plant, it will go through the standard water treatment process. WTP4 will replace the capacity lost when the Green Water Treatment Plant was decomissioned in 2008. WTP4 buildings are being built to achieve a silver rating through the Leadership in Energy and Environmental Design (LEED) Green Buliding Rating System. All facilities are designed to fit in with the surrounding landscape.

The stormwater detention and water quality basins as well as excavation of the clearwell, clarifier and filter complex are already complete. Work continues on the upflow clarifiers clearwells, filter complex and washwater facility, as well as the road in and around the plant.

Jollyville Transmission Main

Construction has begun on the Jollyville Transmission Main, a 6.5-mil, 84-inch diameter tunnel that will connect the water treatement plant to the Jollyville Reservoir for distribution. Water will flow using gravity under most conditions through the main.

 

 

Austin Water Utility is owned and operated by the City of Austin, Texas.