RIVERS – Last September, for the first time in 27 years, the Pend Oreille River's Metaline Falls were exposed as workers lowered the reservoir behind Boundary Dam for dam maintenance.
Starting 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 will be lowered twice, utility officials say, but the falls are scheduled to be most exposed on Sept. 20.
Read on for details.
Workers will lower the reservoir 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.
- This week, the reservoir level is at its normal operating elevation of 1,990 feet.
- Sept. 15-17, the reservoir level will be lowered 20 feet or more.
- On Sept. 19, the reservoir will be raised to 1,990 feet by 9 a.m.
On Sept. 20, the reservoir will be lowered to about 1,960 feet by 9 a.m., exposing the falls.
The pool elevation will remain at that level for about 5 hours while the gate is reattached to the dam.
The reservoir is scheduled to be refilled to the normal operating level of 1990 feet by the end of the day.