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April 08, 2010
DISASTER AND ACCIDENT
Canal leak floods Leaburg yard
|A pair of ducks are looking for a place to nest along a new pond that appeared in Carole O’Brien’s Leaburg property.|
MCKENZIE BRIDGE, Oregon (STPNS) -- LEABURG: Ducks moved in and lawn mowing was put on hold last weekend when a small pond flooded a Leaburg couple’s front yard. Carole and Michael O’Brien have lived on their 1.2-acre parcel for four years but were surprised when water started bubbling out of the ground just below their driveway.
The bubbling became a steady flow that soon filled a low-lying area of their meadow. The water’s source was the Eugene Water & Electric Board’s power canal, which flows along their property line. Dealing with seepage is part of an ongoing maintenance issue for the utility, which constructed the canal some 80 years ago.
EWEB built the four-mile long Walterville canal in 1910 and the five-mile long Leaburg canal in 1929 using local river deposits and construction techniques typ-
ical for the times. Unlike modern earthen civil structures, the gravels, sands and clays used to construct the channels weren’t graded by size or compacted to minimize seepage. As a result, they leak. Over the years, utility crews have managed or reduced seepage by improving the clay core, constructing French drains, and installing ditches and sumps. In addition, officials say natural deposition of fine silts in the canal has lined the canal interiors with a blanket of less permeable material.
Although the O’Briens haven’t had a problem on their property in the 43000 block of the McKenzie Highway in the past, other areas along the canals have.
Recently EWEB staff worked with local property owners and water right holders to re-design and rebuild a vault at Johnson Creek. They’ve also rebuilt an antiquated irrigation water distribution system at Cogswell Creek and maintain a system of ditches, swales and culverts to control seepage from the canal within 3,000 feet downstream of of Leaburg Dam.
“Seepage from the canals is a recurrent challenge along the length of the embankments,” noted Catrin van Donkelaar, the utility’s generation manager, in a December report to utility commissioners. “It can affect neighboring properties and is regularly monitored and managed by EWEB staff,” she noted.
During the summer of 2002, EWEB completed extensive upgrades to the Walterville power plant and constructed fish passage facilities. As part of that work, the canal was completely dewatered over an eight-month period, allowing the clay seal to dry and crack.
The loss of seal revived historical seepage in some trouble areas, which required the installation of almost a thousand feet of French drain and four pumping stations to control it. The clay seal finally re-established itself over a five-year period. Eventually, in 2008, EWEB purchased an at-risk property known as “the Blue House,” next to the Walterville truck weigh station, due to ongoing problems.
For the O’Briens, their leak occurred at a fortunate time. Eugene Water & Electric Board crews were scheduled to shut down the Leaburg Power Canal on Tuesday, April 6th, to perform annual maintenance on the fish screens – as well as conducting inspections of the canal banks and all bridges crossing the canal.
“Maintenance work will in-
clude cleaning and repair of the fish screens, which are situated immediately west of the Leaburg Dam,” according to utility spokesman Joe Harwood. “In addition to the canal and bridge inspections, the crews will conduct an emergency test of the spillway gate.”
The early April shutdown, through Friday, April 9th, was scheduled to coincide with the downstream migration of salmon smolts and their release from the Leaburg Trout Hatchery. It was designed to leave more water in the McKenzie River, hopefully prompting the small fish to continue moving downstream.
The canal inspection was still underway as we went to press. Harwood said the area near the O’Briens is known to have had seepage issues. “What we’re trying to do at this time is figure out if really heavy rains could have had an impact or if it’s a drainage issue. If there’s anything abnormal with the canal we’ll be able to address it. If not, we’ll keep an eye on it and find a solution.”
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