EVERETT – Recent heavy rain is quickly filling the PUD’s Spada Lake Reservoir with water levels predicted to reach the top of Culmback Dam’s morning glory spillway late this afternoon.
Water traveling through the spillway is discharged into the Sultan River, where it flows 16-miles to join the Skykomish River at the city of Sultan. Areas downstream of Culmback Dam should expect to see a rise in river levels due to the spill and an increase in river currents. While difficult to predict, the Sultan River may experience localized flooding, predominantly in low-lying floodplain areas and largely dependent on Skykomish River levels.
The PUD has staff on-site monitoring the dam and spillway and is working in close coordination with officials from the city of Sultan.
“We are coordinating closely with local agencies and have staff regularly monitoring Culmback Dam and flow rates downstream,” said Andrew McDonnell, PUD Manager of Natural Resources. “In advance of the spill, we plan to release approximately 1,000 cfs of water from the base of Culmback Dam to reduce the peak spill volume.”
Much like the overflow drain at the top of a bathroom sink, the spillway allows excess water to safely exit the reservoir before it can reach the top of the dam, helping ensure dam integrity.
“The dam and reservoir are safe and secure, and the spillway is functioning as intended,” said Scott Spahr, Manager of Generation Operations & Engineering at PUD. “This demonstrates the effectiveness of the safety features incorporated into the dam.”
The spill is projected to begin today and extend through the weekend and potentially into Monday, March 23.
Culmback Dam was built in 1965 and raised in 1984 to create the Spada Lake Reservoir, which provides drinking water to most of Snohomish County and carbon-free hydropower to more than 56,000 Snohomish County homes. Each year the dam is inspected by the Federal Energy Regulatory Commission (FERC) and is cleared for continued operation. The PUD monitors the dam 24 hours a day and conducts regular and extensive on-site safety checks.
Source: Snohomish County PUD
Author: Lynnwood Times Staff
