PORTLAND, Ore. – U.S. Army Corps of Engineers reservoir regulators think it’s unlikely that water levels at most of the Corps’ 13 reservoirs in the Willamette Basin will rise much beyond current levels – 3 to 28 feet below their target elevations – without significant additional rain. Maintaining water levels high enough for late summer recreation may also be a challenge.
The Corps started refilling its Willamette Valley Project reservoirs in February for the summer water conservation season. The Natural Resource Conservation Service reports that total precipitation for the Willamette Basin was only about 60 percent of average for February and March, then average for April. The basin’s snowpack has also been melting off faster than average.
‘We responded to the low water supply by minimizing flows from most of our reservoirs in February and March to maximize refill potential,” said Erik Petersen, Willamette Valley Project operations manager. “However, we needed to increase flows again in April and May.”
The Corps is required to meet minimum flow targets on the mainstem Willamette River and many of its tributaries to support water quality and the lifecycles of endangered spring Chinook salmon and winter steelhead. Without the additional water from Corps reservoirs, Petersen estimates the Willamette at Salem would have been almost a third below target in April and May.
The combination of lower than average water supplies and higher releases for fish early in the conservation season may make it difficult to maintain adequate lake levels for late season recreation.
“It’s obviously still a long ways off and there are many factors that could change, but our latest forecast indicates water levels at the end of August may be near the bottom of some popular boat ramps and marinas,” Petersen said.
Boaters and other reservoir users should closely monitor current and expected future water levels when making their summer recreation plans. Current Willamette Valley reservoir and boat ramp levels are available from Portland District at http://go.usa.gov/4U7B. Three-day forecasts and 10-day trends are available from the Northwest River Forecast Center at http://www.nwrfc.noaa.gov.
The Willamette Valley Project’s 13 dams contribute to a water resource management system that provides flood risk management, power generation, water quality improvement, irrigation, fish and wildlife habitat and recreation on the Willamette River and many of its tributaries. Since their completion, the dams have cumulatively prevented more than $22 billion in flood damages to the Willamette Valley. For more information, visit http://go.usa.gov/TMq3.