May 2, 2008 - Bend Bulletin Like Bend’s Drinking Water?
May 20, 2008
Like Bend’s drinking water?
It’s known for its taste, but changes may be on the way
By Kate Ramsayer / The Bulletin
Published: May 02. 2008 4:00AM PST
Bend is looking at changes to the way the city gets its drinking water. The options include switching the source or adding a hydropower facility.
Bend’s drinking water has won awards for its taste and quality — a point of pride for the city.
“You could come see our trophies on the wall,” said Roger Prowell, a water supervisor with the city of Bend.
That taste is because of the young, fractured basalt that the water flows through before it reaches customers, free of minerals that might otherwise make the water salty or metallic, he said.
But with changes in water quality regulations, aging infrastructure and the possibility of a fire in the watershed clouding the water, the city is looking to update its drinking water supply system.
This week, it kicked off the process by asking for outside consulting companies to study different ways the city could deliver water to residents, and analyze the costs and benefits of each. And that will take into consideration how the changes might affect the taste of the water.
The changes could include filtering the drinking water, replacing transmission pipes, installing a hydropower facility or even switching the source of the supply — taking water from the Deschutes River or pumping it entirely from the ground, as opposed to diverting about half of the supply from Bridge Creek.
“Their task is to look at every conceivable alternative,” Prowell said.
Currently, the city of Bend gets its drinking water both from groundwater wells and from surface water that flows down Bridge Creek, which empties into Tumalo Creek west of Bend.
Bend started getting drinking water from Bridge Creek in 1926, Prowell said. After the city boomed post-World War II, another pipe was added to transport the water 11 miles to town. Now, the city uses the surface water year-round, supplementing it with groundwater in the spring and summer, when people use more.
But those water pipes are getting old.
“Both of our transmission lines coming down the hill are seeing signs of stress. We’re seeing pieces of pipe lining showing up in our tanks,” said Tom Hickmann, a water utility manager with the city of Bend. “We really need to start looking at this situation.”
The idea is to replace those two pipes with one larger one, he said.
Other changes that could be in store stem from new Environmental Protection Agency regulations that will require the city to treat water specifically to kill cryptosporidium by 2012. Cryptosporidium is a parasite associated with sewage and animal waste that can cause gastrointestinal illnesses, which can be fatal, especially for people with compromised immune systems.
“The purpose of this (analysis of alternatives) is to look a long ways in the future, and a long ways in the future there are pending changes in regulatory requirements from the EPA,” Prowell said. “We are going to have to institute additional barriers between the bug and our customers.”
The water department has tested for the cryptosporidium bug in Bend’s water supply for years, he said, and only found “exceedingly minimal amounts” of the parasite.
But still, as an unfiltered water source, Bend’s water needs to be treated either with ultraviolet light or chemicals to kill anything that’s there, said Wendy Marshall, an environmental scientist with the EPA’s Seattle office.
“It can’t be inactivated by chlorine,” she said. “We are concerned, and that’s why you do need to increase your treatment for these unfiltered systems.”
There’s a history of increasingly stringent treatments for drinking water to eliminate different contaminants, Prowell said, and one effective solution the city is considering is using UV lights to kill these parasites.
“A part of the study is also looking at a water filtration (system),” he said. “Currently, we don’t do that because the water quality in Bridge Creek can meet all the rules.”
But if there’s a catastrophic fire in the Bridge Creek watershed, that could change instantly, as sediments wash into the waterway. And a fire is definitely a possibility, he said, since many of the trees in the area have been killed by pine beetles.
“The forest is sort of going from green to red,” he said.
To power some of these treatment or filtering possibilities, and to hopefully generate some revenue, the city is considering adding a hydropower facility at the end of a new water pipe.
“If we got a hydro facility there, then we’ve got a source of power for our UV plant,” Prowell said.
A new water source?
Another option would be for the city to find a new source for its drinking water.
Replacing the pipes and adding filtration could cost about $50 million, Hickmann said, so the city wants to make sure that’s the best option.
“Considering that it’s that expensive of a project, we believe it’s absolutely economical to consider all the alternatives,” he said. “If there’s another alternative out there with a lower cost, then we would certainly want to consider that, or at least present that to the (city) council as an option.”
One alternative would be to switch to a completely groundwater-fed system.
That would save the city from having to replace the pipes or put in a filtering system, he said, but it would also mean no hydro- power facility, which could end up making the city money over time.
Switching to groundwater wouldn’t likely change the taste of the water, Prowell said, because both sources provide cold water, and the water chemistry is similar.
But there are other scenarios — such as pumping water from the Deschutes River or irrigation canals — that would result in warmer drinking water in the summer.
“(Deschutes) water is very, very warm during the summer months, and most of the community would not care for 65-degree tap water,” Hickmann said, adding that changes to water taste will be quantified and included in any analysis.
The city could pump more groundwater if it took its existing surface water rights for Bridge Creek, put them back in-stream and used the resulting mitigation credits for groundwater pumping, said Kyle Gorman, a region manager for the Oregon Water Resources Department.
“The effect of that could be beneficial, because there would be more Tumalo Creek water making it into the Deschutes and going past the irrigation diversion,” he said.
And the Tumalo Creek water is good for the Deschutes River because it’s about 5 degrees to 10 degrees colder, said Scott McCaulou, a program director with the Deschutes River Conservancy. And fish like that colder water.
But pumping groundwater near Bend could have an impact on springs lower on the Deschutes River, he said, so that would have to be analyzed.
The city plans to look at all the options, Prowell said, and residents will have chances to provide their comments throughout the process. The city hopes to have a consultant chosen by midsummer and then work on the issue for the rest of the year, he said.
“We just tried really hard to get as many options to the table, and as many out-of-the-box concepts,” he said.
Kate Ramsayer can be reached at 617-7811 or firstname.lastname@example.org.
Published Daily in Bend Oregon by Western Communications, Inc. © 2008