Lake Oswego sewer repair costs go up

Estimates top $90 million
by: Graphic courtesy of City of Lake Oswego,

Capital costs to repair Lake Oswego's sewer system have topped $90 million in new estimates, and early projections to pay the bill show sewer fees increasing by 145 percent over 10 years.

Cost estimates could still increase if land acquisition continues to raise prices or if the Lake Oswego Corporation opts not to draw the lake down to replace a central pipeline in the sewer system.

It could take up to two years for crews to replace a 20,000-foot pipeline at the center of the city's sewer system, the root of its problems. Built in 1963, the pipeline - commonly called the sewer interceptor - is located in Oswego Lake and is too small and potentially vulnerable in an earthquake.

In February, the Oregon Department of Environmental Quality ordered Lake Oswego to replace the pipeline by 2010. Sewage leaks into the lake violated the federal Clean Water Act, prompting DEQ to step in.

Until now, the most recent estimates for the job were in the $65 million range. Those numbers, released in May 2006, were up $40 million from a first round of estimates made in 2001. The early estimates failed to account for 'fluffy muck' in Oswego Lake, or soft sediment that rendered a preferred construction method useless.

Recent estimates, updated and released in a report on the project, compare costs on five proposed designs and range between $27 and $33 million above prices predicted a year ago. The increase accounts for price escalation through 2010, the year construction is set to begin.

The city of Lake Oswego will likely borrow about $100 million to fund the project, according to Joel Komarek, city engineer. Officials plan incremental increases in sewer rates, charged to local water bills, to service debts on 40-year bonds to fund the job.

A preliminary plan for utility fee increases shows sewer fees will rise by 145 percent over 10 years if the city borrows $100 million. Sewer fees currently cost a typical family $49 bimonthly. Over 10 years of fee increases, the typical bill is expected to land at $120 bimonthly.

Richard Seals, finance director for the city of Lake Oswego, could not be reached for comment on the plan.

Komarek said the numbers are preliminary only and still need revision.

'We're only talking capital and escalation costs,' he said.

Operation and maintenance costs still 'need to be dialed into those rates as well, though that's over a longer term,' or the pipeline's projected 75-year-life, Komarek said.

Some elements of the project are still unknown. In August, the Lake Oswego City Council will choose one of five alternate methods to replace the in-lake pipeline. Engineers will recommend an option out of the four in-water and one out-of-water designs proposed.

One of the in-water designs, a steel pipe supported on pilings, appears likely to fall out of the running. The project is by far the most costly, with a capital outlay of $112 million and an estimated $14 million in maintenance costs over its 75-year life.

The remaining in-water proposals are cheaper, with capital costs ranging from $92 to $99 million, all for floating pipelines. The around-the-lake option remains a strong contender with an initial $90 million investment, though the project requires more than twice the maintenance of the others over its 75-year-life, a projected $30 million.

Komarek said possible copper accrual on the floor of Oswego Lake does not appear to stand in the way of constructing any of the designs, provided the Lake Corp drains the lake for the job.

The Lake Corp used copper to control algae for more than 50 years. It's possible high levels in lake sediment would make permits a challenge if the job were done in water.

Komarek said city officials will ask the Lake Corp for one of two types of drawdowns: Either two, 16-foot drawdowns lasting eight months over a two-year period, or a single, 12-month drawdown, also of 16 feet. The single drawdown would curb costs for construction but limit boating on the lake for an entire recreational season.

Two planned public sessions in May will provide an overview of the proposal and take feedback from locals.

'That's going to be their opportunity to weigh in on this issue of drawdown and the duration,' Komarek said.

Local residents can also use that forum to weigh in on replacement options for the pipeline, though cost will likely be a deciding factor.

In the above story, it is reported that city officials will ask the Lake Corp for one of two types of drawdowns: Either two, 16-foot drawdowns lasting eight months over a two-year period, or a single, 12-month drawdown, also of 16 feet.

That information was not entirely accurate. Though two eight-month construction windows would be needed to complete construction on sewers, only one of those would involve a 16-foot drawdown. The 12-month window would require a drawdown for the duration of the job. The Lake Oswego Review regrets the error.