Reservoirs like Detroit are currently extremely low for safe recreation.
“Know before you go,” said Tom Conning, with the U.S. Army Corps of Engineers. “Be safe.”
According to the Corps, the water level at Detroit Dam remains restricted to 4.5 feet lower than maximum for summer simply because of lack of rain, which could impact summer recreation.
“No construction projects nor the interim risk reduction measure for seismic safety have impacted the level,” said Dustin Bengston, deputy operations manager to the Willamette Valley Project. “It has just been a
challenging year.”
As warm, dry weather continues, the U.S. Army Corps of Engineers, Portland District, is seeing a worsening water year as it strives to refill 13 Willamette Valley reservoirs, including Detroit, for the upcoming year.
“We’re getting very back-to-back dryness right now,” said Salina Hart, reservoir regulation chief. “It looks like that’s going to be our pattern moving forward.”
With the prospect of above normal temperatures and below normal precipitation, the dams will face ongoing lower water levels, Hart said.
average for this time of year. Tom Conning
“Our typical Northwest rain that we get tired of, that’s the kind of rain we need to get,” she said. “We didn’t get it this year. There’s not enough precipitation to get us to where we need to be right now. Detroit is doing a lot better than in 2015, but is likely not going to see much refill than we are seeing right now.”
Detroit Lake has seven boat ramps that could be impacted: State Park D, Kane’s Marina, Hoover, Southshore, Cove Creek, State Park G and Mongold.
To learn more about current operations, future forecasts and potential impacts to the Willamette Valley System, more than 40 people participated in an online information meeting in May.
“Any predictions when Kane’s and Detroit marinas will be above the pool?” asked Shelley Engle, Detroit city councilor. “The two owners are going to need to know, especially after the devastating fires of Labor Day weekend.”
Hart told Engle “likely looking like early June. We will get to the full moorage elevations, but the reservoir will draft soon after.”
Participant Bill Sweeney suggested if dryer weather persists that the Corps work on infrastructure projects, such as fixing the end of boat ramps at Fern Ridge – Richardson Point.
“Currently there are large drops at the end of the ramps,” he said. “Fixing and extending these ramps will reduce risk of broken trailers and may extend the water season for some users.”
According to the Corps, the Willamette Valley Project’s reservoirs are currently 67 percent full, possibly impacting early closure for recreation for some higher elevation reservoirs including Detroit.
The Corps goes into every year with plants to optimize their refills, Hart said.
Currently, system-wide reservoir storage is 33 percent below the rule curve. Year-to-date precipitation in the Willamette Valley was 76 percent of normal as of May 17, and Willamette Basin snowpack is currently 51 percent of median.
“Snowmelt helps keep reservoir elevations up in the summer if it lasts and matches outflows – but it only accounts for roughly 10 percent of the system’s storage,” Conning said. “It will be very different for folks out there this year compared to many in the past.”
The Corps manages reservoir inflows based on a “rule curve,” or the authorized maximum elevation on a given day to balance flood risk and storage for authorized purposes. The Willamette Valley Systems’ reservoirs are kept lower in the winter to reduce downstream flooding and refilled in the spring to prepare for recreation and adequate flows for fish.
Portland District encourages the public to visit its “teacup diagrams” before heading out to recreate. Willamette River Basin teacup diagram: www.nwd-wc.usace.army.mil/nwp/teacup/willamette or pweb.crohms.org/nwp/teacup/willamette.
