No quick fix for sewers in Lake Oswego
- Lee van der Voo
- Lake Oswego Review - News
Council will seek a permanent solution for the costly problem
LAKE OSWEGO - City officials have opted not to pursue a temporary fix for Lake Oswego sewers, instead pushing ahead with a permanent solution by 2011.
Costs to curtail leaks from the system in the short-term were considered too high, projected to cost at least $20 to $25 million. Those short-term solutions also would not improve the system's chances of surviving an earthquake.
A critical pipeline in the system - a 20,000-foot stretch that carries sewage from the west end of town east through the middle of Oswego Lake - was built in 1963 and is likely to fail if a significant earthquake strikes.
During a presentation Dec. 19, engineers told the Lake Oswego City Council that the pipeline could fail if a significant earthquake struck the region today.
The city has budgeted $65 million to fix those problems and opted Dec. 19 to apply the funds to a permanent fix rather than a short-term one.
In an earthquake equal to a magnitude 6 on the Richter scale, engineers reported the pipeline would rupture in dozens of places if the earthquake hit within 13.6 miles.
A large coastal earthquake could produce the same results, they said, if it registered an 8.3 on the Richter scale within 71.46 miles of town.
A stronger earthquake has a 15 percent chance of occurring in 25 years.
'We're looking at probabilities. These are short-term probabilities, sort of an understandable risk,' said Gary Peterson, a consultant with Shannon and Wilson, Inc., which evaluated the earthquake risk to the pipeline.
Should the sewer interceptor ever completely fail, the result would be a massive infusion of untreated sewage to Oswego Lake and the Willamette River.
'Our recommendation is that the short-term alternatives not be pursued further,' Jon Holland, a consultant with Brown and Caldwell and the city's contractor on the pipeline project, told the city council.
His firm had previously explored plans for short-term diversions of sewage to a treatment plant in Durham. They also considered pumping sewage around the lake in wet weather.
Both projects were deemed too costly as interim solutions and would provide only short-term relief. They also came with myriad challenges.
New pipeline to curb overflows
The decision by the Lake Oswego City Council to forge ahead with replacing the pipeline aims to avert an earthquake disaster and also contain sewage overflows by increasing capacity in the sewer system overall.
Lake Oswego sewers first began to overflow in 1996. Most problems stem from wet weather infiltrating the system in heavy rain. The city saw massive overflows of sewage in winter 2003 and again in 2005. Projects to clean and rehabilitate sewer pipes in areas adjacent to the pipeline have since eased some problems.
The Oregon Department of Environ-mental Quality has meanwhile warned Lake Oswego about the overflows, insisting on a fix. The city is currently facing fines for the 2005 overflow. Those penalties may be waived in lieu of a firm plan for replacing the pipeline.
Engineers now plan to design two options for a pipeline, whittled down from an original 20 that have been probed since 1999. Still on the table are a new, buoyant in-lake pipeline and an out-of-the lake design, both due out in January. Construction on either project is set to begin in 2009, pending approval of one of the two options by the city council.
'We've talked about the advantages and limitations of the out-of-lake versus the in-lake (options),' said Joel Komarek, city engineer for Lake Oswego and the liaison to contractors on the job.
'We'll be looking at capital costs. We'll be looking at long-term operations and maintenance costs, reliability. Those particular criterion are probably the most important in answering the question as to which option is probably going to be best in terms of meeting the needs of the community,' he said.
Public hearings planned
The city council plans to take public testimony on the sewer replacement options and, through those hearings, educate local residents about the inconvenience caused by construction of either one.
'It's going to be unlike anything the community has experienced since the original pipe was built and I would venture to say it will be very different from that,' said Komarek.
'What we want to ensure to the best that we can is that the public understands the complexity of the project and that there will be impacts to the community during any construction and there will be impacts of either (construction method),' he said.
Public hearings will likely take place in late winter or early spring 2007, after the city council reviews the proposed designs.
Copper issue left to Lake Corp
Whether city leaders opt to pursue a pipeline in or out of Oswego Lake, in-lake work is still required for construction, according to Komarek.
He said he does not expect either method to trigger an environmental review by federal officials, however, based on information that stems from talks between the city's consultants and federal regulators.
The city halted work on the project for more than a year in 2003, in part because of concerns that the historic use of copper sulfate by the Lake Corp to treat algae could cause problems if federal regulators required environmental testing in the lakebed. The federal Corps of Engineers can require such tests for in-water construction because of the Clean Water Act.
A toxicologist hired by the city said at the Dec. 19 presentation that copper would be a likely find in the lakebed, along with other urban toxins, but would not cause concern for public health because copper affects only aquatic life.
'I don't expect this project to generate concern that would trigger some sort of extra (environmental) sampling effort,' Komarek said. 'The Lake Corp and its use of copper, in my mind, is not related to this project. If that's an issue, it's an issue the Lake Corp has to deal with.'
Overflows likely in heavy rain
As wet weather continues, sewage overflows are likely to remain a problem until a new pipeline is built. The severity of storms has dictated problems in the past, since the overflows stem from the infiltration of groundwater into sewage pipes.
So far, the city has not notified homeowners of sewage overflows but continues to provide notice to the Lake Corp and the Oregon DEQ when they occur.
Lake Corp officials opted to notify shareholders of the last sewage overflow Dec. 14 after power outages caused mechanical failures that led to overflows in the Palisades area, on Cardinal Drive and in Foothills.
In an e-mail to shareholders, Lake Corp officials urged residents to sign up for the city's CodeRED program.
City officials said they would use the system in the event of a serious sewage overflow. Residents can register with the program at www.ci.oswego.or.us/home
/news/CodeRED.htm or by calling the Lake Oswego Citizen Information Center at 503-635-0257.