The Corps has held releases from the dam to 4,100 cubic feet per second in the past week to help mitigate flood impacts that have been occurring at relatively low flows due to a continued reduction in channel capacity on the White River in the Pacific and Sumner areas. But with the pool at 40 percent full and still rising, the risk to public safety is growing along with the pool. Corps officials are increasing dam releases to 4,700 cfs to reduce those public safety risks.
Inflows to the dam in the past week have been as high as 10,000 cfs. Corps water managers estimate that the length of time to evacuate the pool at a release rate of 4,100 cfs in current weather conditions could take as long as 14 days, which presents an unacceptable risk to public safety given the unpredictability of forecasts and rapidly changing weather conditions during flood season.
“Public safety is our number one priority,” Buck said as he stressed his growing concerns to a crowd gathered in Pacific for a public meeting hosted by city officials Feb. 18. “It’s important for everyone in this area to understand that we are losing channel capacity here at an alarming rate.”
Mud Mountain Dam’s single authorized purpose is to manage the risk of flooding and typically does not store a pool, except during flood events.
“With a reservoir pool almost half full, we must take seriously that we are still in flood season and we have a reduced capacity to store water in that reservoir—it can fill up fast and take a long time to empty,” said Ken Brettmann, Seattle District senior water manager. “We are extremely vulnerable right now and we need increase outflows from the dam so we can reduce the pool as quickly as possible.”
Corps river spotters will periodically monitor conditions today in the Pacific and Sumner areas on the White River because of the unpredictability of channel capacity there.
Reservoir data from Corps reservoirs are available on line at:
Public Law 84-99 enables the Corps to assist state and local authorities in flood fight activities and cost share in the repair of flood protection structures. The purpose is to prevent loss of life and minimize property damage associated with severe weather.
Private citizens seeking sandbags should contact their local government offices.
The National Weather Service issues Flood Watches and Warnings.