Knowing the Worth of Water

Austin WTP No. 4  |  Austin, Texas

Project Overview

The Water Treatment Plant No. 4 project transfers water from Lake Travis to the 50-mgd pump station through an intricate tunnel system to better serve the city of Austin, Texas. This project functions as a creative solution to mitigate environmental concerns and sustain an increasing population for many years to follow.

In a growing community where water scarcity is a reality, the City of Austin had to develop a water treatment facility that would provide water to the city well into the future. MWH Constructors, serving as construction manager at-risk worked hand-in-hand with the City to construct Water Treatment Plant No. 4 (WTP4). Because the project has multiple components, the City of Austin chose the construction management at-risk (CMAR) method to keep all components in a single contract, making this the largest CMAR tunneling job in the state of Texas.

Project Scope

Construction of the facility included an intake system in Lake Travis, a raw water tunnel and pump station, a treatment plant and the Jollyville transmission main. The water’s journey starts at the raw water intake structure in Lake Travis. Raw water travels by gravity via a 9-foot diameter, concrete lined tunnel to a raw water pump station nearly a mile away, where 1500 hp vertical turbine pumps lift the water more than 400 feet. The raw water is pumped the final mile to the plant where it goes through a treatment process before entering the Jollyville Transmission Main (JTM), a 6.5-mil, 84-inch diameter tunnel that connects the water treatment plant to the Jollyville Reservoir. From this reservoir, the treated water enters the water distribution system.

Manhours worked


Local subcontractors used for WTP4

Millions of dollars in savings returned to the City of Austin

“This is one of the largest projects the City has completed to date and all work was completed within 1% of the targeted budget, which was established over 10 years ago. The partnership formed among the City, MWH Constructors, and the design team under a Construction Manager at-Risk (CMAR) arrangement allowed challenges to be identified early and solutions developed without impact to the project’s scope. The collaborative environment was largely responsible for a seamless and error-free commissioning and startup performance, the project being completed in an environmentally sensitive area without incident, a flawless safety record, and exceeding all small, minority, and woman-owned business participation goals.”

Howard S. Lazarus, PE

Director of the Public Works Department, City of Austin