Last September, for the first time in 28 years, the Metaline Falls on the Pend Oreille River were exposed as workers drew down the reservoir behind Boundary Dam for dam maintenance.
This week, the falls will roar again as Seattle City Light workers continue the project by replacing a 312-ton sluice maintenance gate.
The reservoir is being lowered twice, utility officials say, but the falls are scheduled to be most exposed on Tuesday.
Workers will lower the pool and back a trailer carrying the gate into the reservoir, then raise the water level to float the gate and move it near the dam. A second lowering of the reservoir will allow crews to mount the gate back on the dam.
Low water conditions through Wednesday are preventing access at all boat launch facilities on the Boundary reservoir, including the Boundary Forebay, Metaline Park, and Campbell Park immediately below Box Canyon Dam.
The Boundary Dam Forebay Recreation Area is scheduled to reopen Sept. 30.
Earlier this week, the reservoir was lowered 20 feet or more.
Today, the pool level will start coming up. Monday, the reservoir will be raised to full pool (1,990 feet) by 9 a.m.
On Tuesday, the reservoir will be lowered to about 1,960 feet by 9 a.m., exposing the falls.
The elevation will remain at that level for about five hours while the gate is reattached before the reservoir is allowed to refill to the normal operating level of 1,990 feet by the end of the day. That will smother the rapids again, possibly for another two or three decades.