PORTLAND, Ore. -- PORTLAND, Ore. -- Responding to less-than-expected precipitation, the Portland District, U.S. Army Corps of Engineers (USACE) is hosting a virtual information session this week regarding the Willamette Valley System’s (WVS) dams and reservoirs summer forecast.
Water managers will explain the latest forecasts, refill projections, and factors influencing water levels across the region. This event offers a unique insight into one of Oregon’s most complex and crucial water management systems.
💻 Virtual Information Session
🗓 Thursday, June 26, 2025 | 🕕 6–7 p.m.
🔗 Join Online (MS Teams)
Meeting ID: 993 525 821 40
Passcode: Rj73CV7E
📞 Dial in by Phone (U.S.):
+1 601‑262‑2433
Phone Conference ID: 151 499 265#
USACE encourages questions but asks participants to type their questions in the chat window or send an email to cenwp-pa@usace.army.mil with their question by June 25.
STORING WATER FOR OTHER PURPOSES
Beginning in mid-May, USACE maintains reservoir levels as high as possible to conserve water for recreation and other congressionally authorized purposes, such as irrigation and hydropower. After the rainfall dwindles in late-spring, snowmelt is the primary water source that helps maintain reservoir levels through the summer.
“Spring conditions are vital to refilling the Willamette Valley,” said Salina Hart, the Portland District reservoir regulation and water quality section chief. “During the spring, we’re typically balancing flood risk management and reservoir refill for the conservation season.”
While preparing for the 2025 conservation season, data indicated a typical water year. However, since April, the region has seen significantly less precipitation than forecasted—modifying the original estimates and signifying a drier year.
During this year’s drier-than-normal conditions, USACE has needed to release reservoir water to support the mainstem flow on the Willamette River. Mainstem flow targets are required by the National Marine Fisheries Service’s Biological Opinion (BiOp). The BiOp is a consultation process with the U.S. Fish and Wildlife Service and National Oceanic and Atmospheric Administration that calls on USACE to ensure dam and reservoir operations have a limited impact on listed endangered species.
“The goal of the BiOp is to ensure the health of the river and the health of endangered species,” said Hart. “During drier conditions, more water is required from reservoirs to compensate for lack of rainfall.”
As of June 18, the overall level for the 13 reservoirs in the WVS is 64% full, down 10% since April.
CHECK BEFORE YOU GO
Before hitting the water this summer, USACE recommends checking real-time reservoir levels online:
🔹 Teacup Diagram
WHY IT MATTERS
Managing the WVS isn’t just about floods and forecasts; it’s a year-round balancing act of science, safety and community needs. From hydropower and irrigation to water quality and recreation, the reservoirs play a key role in everyday life across the region.
The primary purpose of the WVS is flood risk management. Water managers follow a reservoir elevation guide, or rule curve, that helps the balance flood risk management with the other authorized purposes, like hydropower generation and recreation, all throughout the year. This ensures we always have enough space (based on the time of year) behind the dams to capture rain events so that communities downstream don’t flood.