Driving along a pair of narrow dirt tracks overhung with trees and behind backyards, Steve Johnson points out where the Central Oregon Canal in southwest Bend breached and poured a quarter-million gallons of water into a neighborhood in 2005.
Johnson, the district manager of the Central Oregon Irrigation District, is growing increasingly concerned about homes and businesses encroaching on the canal, which runs from the Deschutes River to farms and ranches in Alfalfa and Powell Butte.
“That breach really dramatized to me the potential risk that we have,” Johnson said of the November 2005 incident.
The best solution for Johnson is to start piping canals in the city, though such projects would be costly, and it is unclear who would pick up the tab.
The 2005 rupture, which flooded parts of eight homes, happened after water in the canal rapidly eroded soil around a recently installed sewer line from a subdivision being built nearby, Johnson said. Even though the COID had permitted the contractor’s work near the canal, the disturbed soil simply was not compacted enough.
He said the canal’s earthen banks, many of them pushed up and compacted more than 100 years ago, are in good shape overall. And as long as they aren’t disturbed by nearby construction, there’s no reason to believe that the canals are going to fail outright anytime soon, he said.
COID employees drive the canal nearly every day, looking for moisture on the outside of its banks, dead trees, holes from burrowing animals or other signs that water is seeping through the banks.
“You really can’t monitor every square inch of a canal that’s 40-something miles long,” Johnson said.
Though there have been no big incidents since the 2005 breach, Johnson raised the risk at a Bend City Council meeting last week, when a zoning change for a 432-unit condominium project next to the canal and Reed Market Road was up for a vote.
The project’s plans call for adding a bridge across the canal to connect it with Reed Market, about 1,000 feet east of Southeast Third Street. Because the COID has an easement on either side of its canal, it has the power to limit work that happens nearby.
Johnson said the banks of the canal aren’t stable enough to withstand construction like that, and that the only long-term solution would be to pipe the canal through that entire area.
Driving slowly on the road atop one bank of the canal Tuesday, Johnson pointed out all the nearby development: dozens of homes; a strip mall with ice cream and video stores; an auto parts store with its parking lot 10 feet below the canal; and the Sun Ranch Mobile Home Park on the canal’s south bank, which will be razed for the condominiums.
If the canal were to breach near the planned development, water would flow across Reed Market and back toward Third Street, he said. And even if the water was cut off immediately at the top of the canal, the torrents out of a rupture would last for several hours.
Johnson’s piping solution is more complex and costly than it may seem at first blush.
“You can’t just do this, plop a 50-foot piece of pipe in the middle of the canal, because you can’t necessarily get all the water in the pipe,” Johnson said.
Such a pipe would have to start where the canal’s current is faster — in that case where it passes under Third Street.
And with the city’s possible future plans to create a new intersection at Reed Market and American Lane, Johnson would like to extend that pipe past the Burlington Northern Santa Fe railroad tracks to the east.
Cost for such a project: $5.5 million, Johnson said. In a perfect world, he’d like to do it in the next five years, too.
“It’s fair to ask the developers for a share,” Johnson said. “I think it’s likely the city and COID will have to pay something (also).”
Bend Public Works Director Ken Fuller, who talked with Johnson recently about the issue, said it isn’t up to his department whether or not the city would chip in for such a project.
“That’s really a City Council decision about whether they want to propose funding,” Fuller said.
There are many benefits of piping besides eliminating flood risk, Johnson said. The COID would be able to return about five cubic feet per second worth of water to the Deschutes River, flows that are lost to water seeping into the ground below the canal. And the district wouldn’t have to worry about people falling in and drowning, he said.
“It just depends on the economics, really,” said Councilor Mark Capell. “I’m willing to have the conversation, and when the economics make sense, let’s do it.”
For the long term, Johnson would like to see the city and COID coordinating more about the future of the canals.
“The pace of development has been so fast,” he said, “these kinds of planning issues, to think that far ahead, to do this the right way, it’s a challenge for everybody.”