News Release
| Release Number: | 02-105 |
| Dated: | 6/12/2002 |
| Contact: | Heidi Y. Helwig, 503-808-4510 |
Portland, Ore.-Turbidity levels in the McKenzie River have dropped extensively over the last several weeks, said George Miller, U.S. Army Corps of Engineers project manager for the Willamette River Temperature Control Project.
The Corps stopped drawdown of the reservoir about three weeks ago when the residual pool elevation reached 1,400 feet, 25 feet shy of the original target of 1,375 feet above mean sea level. Turbidity levels had spiked as high as 201 NTUs, or Nephelometric Turbidity Units, which are units of measurement quantifying the degree to which light traveling through a water column is scattered by particles of matter in the water. On Wednesday, June 12, the NTU level was down to 16, Miller said.
The Eugene Water & Electric Board (EWEB) also has seen turbidity levels drop at its Hayden Bridge water-filtration plant on the lower McKenzie. Current levels are about 3 NTUs, compared to normal levels of 1 to 2 at this time of year or the elevated levels of 10 to 15 NTUs experienced just two to three weeks ago. "We are approaching normal conditions," said EWEB spokesman Lance Robertson.
The utility, which serves about 162,000 people in Eugene with drinking water, had to scale back its processing of water during the higher turbidity period, largely because filters had to be cleaned more often, Robertson said. EWEB has been concerned that continued high turbidity could affect the utility's ability to process enough water during a summertime heat wave.
Weekly water quality tests by EWEB have consistently revealed the water is safe and free of contaminants, including pesticides and metallic substances.
The most recent water quality tests performed by the Corps below the reservoir, above the reservoir and at Hayden Bridge also are consistent with EWEB's data. There were no metals, PAHs (polynuclear aromatic hydrocarbons) or pesticides of concern detected in the water samples, Miller said.
Though the Corps is pleased with the continuing decline in the turbidity and positive water quality results, "We didn't see as quick a drop as we hoped for once we completed the Cougar Reservoir drawdown," Miller said, acknowledging that NTU levels needed to drop a considerable amount before the fly-fishing community saw dramatic results in that fishery.
The fish themselves, however, appear unharmed, Miller said. "The National Marine Fisheries Service collected fish samples in the lower river and ODFW (Oregon Department of Fish and Wildlife) collected them in the reservoir pool. Both came to the same conclusions--that the fish were not being harmed by the turbidity," Miller said.
Other concerns raised from community members, ranging from compensation for lost revenue to the permanent loss of the once pristine river, were voiced at a public meeting on May 15. The Corps has a written record of each question and comment made and will further address those concerns in writing. Final responses will be posted on the Corps' website, Miller said, adding that it will take some time to adequately address each one.
"At the May 15 meeting in Walterville, we heard dissatisfaction and frustration expressed by local citizens and business owners," Miller said. "We have a clear understanding of those areas that need additional attention before next year and we are addressing them now."
The project is the Willamette River Temperature Control Project, which will take three years to complete. Though two years of construction remain, Miller said the worst of the turbidity is over. The drawdowns slated for 2003 and 2004 are scheduled to occur before trout season opens and will involve draining less water from the reservoir, as long as we do not have to manage a late-season flood. The Corps plans to keep the reservoir as close to its current elevation (1,400 feet) as possible throughout the winter, Miller said. Also, additional public meetings will be held prior to future drawdowns, he said.
The purpose of drawing down Cougar Reservoir was to allow for construction of a multi-level intake tower. The tower will allow the Corps to draw water from differing depths in the reservoir, mixing it to the optimum water temperature for release below the dam to more closely match natural conditions needed by fish. The changes will improve river conditions for salmon and resident fish in the South Fork McKenzie and McKenzie rivers.