Expense to tap Bull Run goes up
Latest estimates of the expense of bringing Portland water to Sandy are much higher
The city of Sandy could spend nearly $3 million more than initially planned to build infrastructure and tap into water from the Bull Run watershed.
The project, which was projected to cost $9.6 million last March, was described to the Sandy City Council Monday night as costing anywhere from $11.7 million to $12.2 million.
But the costs are just estimates made prior to design and construction.
The council was given a preliminary design report from Murray Smith and Associates for the Bull Run intertie project, which would bring the region's best water - from Bull Run Reservoir - to Sandy for at least the next 25 years.
Public Works Director Mike Walker says Bull Run water would become the city's primary source of water, even though it can get all it generally needs now from its current source: Alder Creek and Brownell Springs.
About 1.5 million gallons per day is available from the city's current sources. When Bull Run water begins flowing in Sandy pipes in 2013, the city will take a minimum 500,000 gallons a day, but it could take up to 3 million gallons.
Decades down the road, the city could carry up to 10 million gallons a day through the 24-inch-diameter pipe it buries in 2012 and 2013.
Connecting to Bull Run water is the city's backup plan as well as its future growth plan, because the existing water sources cannot support future population growth during peak use.
Walker brought the issue to the council to get its recommendation of a few major details such as pipe size, type of material to construct the reservoir and the size of the booster pumping station.
Councilors were generally accepting of the plan; however, the price increase did raise some questions.
Councilor Carl Exner and Mayor Bill King were in favor of the more expensive concrete reservoir, but Exner had some reservations about the pipe size.
He asked Walker why 18-inch pipe would be placed along Bluff Road now and when a larger volume of water was needed another pipe would be added alongside the 18-inch pipe. Why not put a 24-inch pipe in now, he asked.
There is a saving of cost to bury five miles of the smaller pipe (instead of the larger diameter) in the rural area, but Walker said there would be additional cost to add another pipe at some time in the future when demand and population increase required more water.
But in the city, where workers must dig through pavement and avoid traffic and other utilities to place water pipe, he suggested placing the larger size first, to avoid digging it up again.
The larger diameter piping system is necessary, Walker told the council, to avoid large fluctuations in water pressure (more than 10 pounds per square inch) that negatively affect household appliances such as ice makers, washing machines, dishwashers and shower heads.
The project would connect to the Portland pipeline near Hudson Road, with a 24-inch diameter line about 400 feet long to a booster pumping station and then about five miles of 18-inch diameter pipeline alongside Bluff Road to Sandy's urban growth boundary, where it would expand to a 24-inch pipe through the city to a one-acre parcel near Revenue, McElroy and Scenic streets.
At that site, which the city plans to purchase from Frontier Communications, the city would build a one-million-gallon concrete storage tank - partially above ground and partially below.
That storage facility would be connected to the city's water distribution system and the reservoir east of town.
Councilor Jeremy Pietzold suggested it would be better to bury a two-inch conduit along with the pipe so controls can be wired through the conduit instead of using wireless technology.
Pietzold said he was thinking ahead in the case fiber was desired in the Bluff Road area, it could be routed through the existing conduit instead of digging and burying another conduit.
Councilor Lois Coleman said she was in favor of the northeast Sandy location selected for the reservoir, which Walker described as about 70 feet in diameter, partially buried, but above ground 10-15 feet.
Walker said 20-year revenue bonds would be sold to cover costs of the project - millions of dollars that would be paid back over time through fees residents pay for water service.
For more information, call Walker at 503-489-2162.