Portland, Ore. -- Water managers at the Portland District, U.S. Army Corps of Engineers are preparing already-swelling reservoirs in the Corps’ Willamette Valley dams for additional rainfall that is forecasted in the upcoming days.
At Fall Creek, this preparation included increasing releases to historic rates.
“The system is full, and in order to protect people and important dam infrastructure, we’re going to have some release rates that are going to impact a number of people,” said Erik Petersen, Portland District Project Operations Manager for the Willamette Valley. “Given the circumstances and forecast, we need to push the controlled water releases that we can right now to maintain space in the reservoirs for the forecasted water inflow.”
Balancing dam outflows with projected water inflows helps the Corps avoid uncontrollable releases of water from the dams.
“Our engineers are monitoring the dams, the instrumentation, and downriver embankments 24 hours a day,” said Petersen. “As of right now, there are no remarkable changes or causes for concern.”
Portland District team members are working around the clock to coordinate efforts with local governments, including Lane County, and other stakeholders to manage water flows safely.
Teams at the Portland District are running forecasting models multiple times a day in conjunction with the Northwest River Forecast Center to predict inflows to Willamette Valley reservoirs, which allows them to plan dam outflows for downstream flood risk management.
“Forecasts include inherent uncertainty, and we do the best we can with the information we have,” said Kathryn Warner, and environmental engineer at Portland District. “In this case, an unusual weather system brought much more rain than initially forecasted and was coupled with snowmelt, which also contributed to the rapidly rising inflows.”
Corps officials advise the public to keep a safe distance from dams and inundated areas while they manage the high water volume.
“We’re asking the public to prioritize their individual safety,” said Petersen.
Residents in affected areas should continue to follow the instructions of local emergency managers.
For the most up to date official river flow information, refer to the Northwest River Forecast Center at www.nwrfc.noaa.gov/rfc/.
Information about flood warnings and watches and expected flood stages can be obtained from National Weather Service at https://water.weather.gov/ahps/.