By(May 14, 2013)
Water District’s joint plan to build a pipeline to the Willamette River is already gaining momentum.
The city and TVWD, Oregon’s second-largest water provider, formally designated the Willamette River near Wilsonville as the secondary water source of the future at meetings in February and April respectively.
Hillsboro uses a combination of Tualatin River, Henry Hagg Lake and Barney Reservoir water currently, but demand is expected to outpace supply, and the city says a secondary source is needed by 2026.
After three years of studying possible sources, Hillsboro’s Utilities Commission vote in February was a formality.
The heavy lifting on the estimated $870 million joint project, which includes construction of a 26-mile pipeline, 30 years of operational costs and construction of a new water treatment plant and necessary reservoir storage, will be years in the making.
It appears that discussions of one possible pipeline section began in earnest in January, according to Mark Knudson, TVWD chief engineer, who briefed the Utilities Commission on Tuesday.
Joined by staff from HDR, an engineering and architectural consulting firm, Knudson told the commission the district “pretty much jumped” one critical section of the pipeline immediately after being approached by Washington County in January.
A road project in unincorporated Washington County that would extend Southwest 124th Avenue south from Southwest Tualatin-Sherwood Road and east to connect with Southwest Grahams Ferry Road, could be a critical piece of the puzzle.
Jeff Fuchs, HDR’s associate vice president of the water business group, said building a 1.5 mile section of the pipeline underneath the new section of 124th Avenue is feasible. It would also save the city and TVWD between $30 million to $75 million compared to other possible routes, he said.
Burying the six foot steel pipe some 30-45 feet underground would call for extensive dynamiting, according to Fuchs. Excavation work makes sense now, rather than later, he said. “Once the road is there you don’t want to excavate with dynamite.”
HDR studied the possible pipeline connections both north and south of the 124th Avenue site, Fuchs said, and found several “strong routes.” Three alignments jutting north of the road extension would call for “deep tunneling” under the Tualatin River, Fuchs said.
Hillsboro’s Water Department budgeted $1 million for the 2013-2014 fiscal year, according to Director Kevin Hanway, to study the actual alignment of the 26 mile pipeline.
That process, Hanway said Tuesday, was expected to take several years. An opportunity to piggyback on Washington County’s project threw that timeline to the curb.
“We didn’t expect to have this opportunity,” Hanway said of the county project. “But we’d be foolish not to take advantage of it.”
The county is still in the design phase for the roadway, according to the project’s website, with construction likely to begin sometime in 2015. Hillsboro and TVWD are expected to submit preliminary design plans for their portion of the 124th Avenue project by the end of 2013.