It's in the water
July 3, 2008 · Updated 3:32 PM
Those who wash their cars, fill their glasses, water their lawns and flush their toilets with city water may find their rates rising over the next few years as Oak Harbor undertakes a $6.5 million water system improvement plan.
Its not yet known how much rates will increase if at all to accommodate the lengthy list of improvements, which officially spans six years, from 2003 through 2009.
But it is clear that the citys plan calls for significant investments everything from building a 6,000-gallon surge tank that will help keep water flowing in an emergency to building a new back-up reservoir to help meet the demands of a growing population.
Oak Harbor City Council members signed off on the new plan earlier this month.
The plan was submitted last fall to the states Department of Health. The agency approved the plan in March.
The state requires cities to update water system plans every six years to ensure sufficient quantities of safe drinking water.
Oak Harbor purchases its water from the city of Anacortes, which operates its own water utility, pumping water from the Skagit River.
That water flows westward from the river through transmission lines along Highway 20. Oak Harbors water lines hook up at Sharpes Corner, (where Highway 20 makes the curve away from Anacortes and toward Whidbey Island), run underneath the Deception Pass Bridge to the Ault Field pump station at Whidbey Island Naval Air Station, and then into the city of Oak Harbor.
Three major projects listed
The three biggest projects on the list are a 3 million gallon reservoir, expected to cost about $2.2 million, and relocating two water lines near Deception Pass as part of a Washington state Department of Transportation highway improvement project. The cost to the city to move the two lines, which currently sit in the pathway of the project, comes with a $1 million price tag.
Also, the city must move its water lines along Highway 20 on Fidalgo Island at a cost of $2 million.
City staffers are currently finishing up a water-rate analysis. The water system plan was the final piece needed before the study can be completed sometime next month.
The city last raised rates in May 2002.
Some rate increases are necessitated by the city of Anacortes, which annually boosts water rates to its customers. Oak Harbor officials sometimes pass on those rate increases to city residents. The average homeowner presently pays about $40 a month for water in the city.
The other ongoing cost to Oak Harbor residents is the maintenance and operation of the citys water lines, which stretch about 20 miles from Anacortes.
In recent years, a small but vocal group of residents has worried that the city lacks protection from a sudden surge in water flow.
Such a situation could occur in an emergency, should the city temporarily shut off its water pipes. In such an event, the city would continue drawing water from wells and reservoirs.
However, turning the system back on could cause a surge in water that would send a high-pressure wave through the pipe, busting the line. Or, in another scenario, a surge could cause a negative pressure wave that would create a vacuum, causing the pipe to collapse.
In a work session held prior to last weeks City Council meeting, some City Council members expressed concern about the possibility of a water surge.
Council member Larry Eaton questioned why the city has not tested the water systems ability to withstand a surge.
To which city engineer Eric Johnston replied: I wouldnt want to test the airbags on my car.
But it has to be tested, Eaton persisted.
City staffers reassured Eaton and other concerned council members that the likelihood of a surge was slim and that the new plan, which will build a surge tank at Ault Field in 2006, should ease concerns.
The surge tank is estimated to cost about $150,000.
The risk for damage from a water surge increases as water flow and velocity increase. In other words, the greater the volume of water that flows through a pipe, the greater the speed at which it flows and the greater the possibility for damage should that water suddenly stop flowing, only to be quickly turned back on again.
Water demand sure to increase
Currently, city residents use an average of 1.6 million gallons per day and the naval air station uses 1.1 million gallons, for an average velocity of 1.3 feet per second.
By 2009 the citys daily demand is expected to climb to 1.8 million gallons per day, with water consumption at the naval air station at 1.2 million gallons per day, which works out to 1.4 feet per second in velocity.
Thats not enough of a jump to be overly concerned about a possible surge, city staffers said. By 2009, of course, a surge tank should already be built, deflecting such concerns.
This is something that we as engineers have been moving forward with, Johnston said. We want to solve a problem before it happens.
So far, there has yet to be a damaging surge since the first water pipeline was constructed in 1942, as a way to supply water to the Navy base. In the 1970s, a second water line was built between Anacortes and Oak Harbor to supply city residents. Ownership of the two lines was later transferred to the city, through a joint agreement with the Navy. The Navy now buys water from the city.
Earlier this year the city undertook a water system vulnerability assessment at a cost of $50,000. The study was done in response to the federal Homeland Security Act. It addresses potential outside threats to the citys water supply.
Such studies are considered to be essential during these days of heightened terrorism threats. And its another reason that Oak Harbor maintains a number of back-up water supplies, in case the main water system is ever shut down.
Even without the addition of the 3-million gallon south reservoir, planned for 2009, the city is able to draw water from three emergency wells and from the Navy base, which maintains back-up water supplies.
Still, the city is in the hunt for new water sources.
Cathy Rosen, the citys public works director, mentioned looking into desalinization plants, a high-tech and somewhat costly process of turning salt water into drinking water. She also said the city needs to study whether to rehabilitate wells that were abandoned when the city hooked into the Anacortes water supply.
Read the water plan
The new $6.5 million water system plan approved by the Oak Harbor City Council last week will serve as a blueprint for the next six years.
The complete plan is available for public review at the engineering division of the citys Development Services Department at City Hall, 865 S.E. Barrington Drive.
Portions of the plan will be published on the citys website (www.oakharbor.org) in the coming weeks.