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AWU Director projects $10 million savings on WTP4 construction
Monday, February 7, 2011 by Josh Rosenblatt
The Austin Water Utility is estimating that Water Treatment Plant 4 will come in more than $10 million under budget. However, AWU Director Greg Meszaros was quick to point out to the Council’s Audit and Finance Committee last week that that estimate is something of a moving target.
As of Jan. 24, Meszaros said, AWU is estimating that WTP4 will cost $496.5 million, or $11.2 million less that the $508 million budget baseline set up approximately 2 1/2 years ago when the project site was moved from Bull Creek to Bullick Hollow. Those revised numbers include $2.1 million less in engineering and construction services and $6.5 million less in construction contracts.
AWU did revise some costs upwards, though, including the cost of environmental commissioning, which involves an outside group reviewing the project’s environmental compliance.
The city has spent $102.2 million on WTP4, with $253 million under contract.
Council Member Bill Spelman was heartened by the news that the project could cost less than initially estimated, but he asked Meszaros why two big-ticket items, the raw water intake and tunnels and the transmission main system, had their budget estimates revised upward. The raw water intake and tunnel work is currently under contract for $62 million, $6.3 million more than the initial budget baseline estimate. Meanwhile, the estimate-at-completion cost for the transmission main system, which is not yet under contract, jumped $10.5 million since 2008, when it was budgeted at $93.4 million.
Meszaros said the reason for the higher cost of the raw water intake and tunnel work has to do with the difficulty of the work itself. The job requires heavy marine work, including construction 300 feet down on the floor of Lake Travis as well as major tunnel work under the lake to the raw water pump station. The shaft site at the station, Meszaros pointed out, is 45 stories straight down.
“It is very difficult work to estimate because there are just a few companies that do it,” Meszaros said. “We had a lot of qualifications for firms that did this work because you don’t want just anyone working 300 feet down on Lake Travis. You really want to make sure that people have done this before and can demonstrate that they can do this.” He said the project has assembled a team made up of national contractors and several local subcontractors.
“Actually I think this bodes pretty well because this is the kind of area you can get a very big bust in. You can think it’s going to cost $50 million and then the bids come in at $100 million; it’s very hard to estimate that kind of marine work,” Meszaros said.
As for the transmission main system, Meszaros said the upward revision was a result of neighborhood and environmental concerns over the project’s original plan to construct an open trench in the Spicewood Springs neighborhood. In order to address those concerns, the project team decided to change the construction of the main from open trenching to tunneling, resulting in a higher cost estimate.
“As we started working with the Spicewood neighborhood, we started to realize that there was no reasonable way we were ever able to construct (the main) down the middle of Spicewood with an open trench,” Meszaros said.
Project managers also determined that trenching could cause environmental problems. “The Jollyville line runs underneath the Bull Creek Preserve; we knew there’s endangered species issues there, particularly a lot of concern with the Jollyville Plateau salamander. Our Environmental Commission team advised that tunneling was the only option,” Meszaros said.
Meszaros said the new $103 million estimate for the transmission main work reflects not just the move from trenching to tunneling but the fact that the project will require deeper tunneling and fewer shafts than normal in order to avoid contact with environmentally sensitive areas.
“The original assumptions changed considerably from a couple of years ago to today,” Meszaros said.
AWU will be providing a briefing on the WTP 4 project to the Audit and Finance Committee quarterly.
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