Lake Chelan levels to drop to prepare for work on the hydropower dam

Lake Chelan may be lower than recent years in spring 2027 because of planned maintenance at the Lake Chelan Dam.

Both generating units at the Lake Chelan powerhouse are scheduled to be out of service in April and part of May. During this time, water can pass through the dam to the Chelan River, but not through the powerhouse. To prepare for the outage, Chelan PUD may potentially lower the lake about a foot below Chelan PUD’s typical target elevation by April.

One of the goals of lowering the lake gradually is to prevent a sudden, large release of water into the Chelan River, which could cause erosion and damage fish habitat. Protecting salmon habitat is a priority under Chelan PUD’s federal license to operate the Chelan powerhouse.

Every year beginning around September, Chelan PUD gradually draws down the lake to make room for fall and winter precipitation as well as next spring's snow runoff. Lake levels last year trended above the target operating curves due to the December floods.

“Because we lowered lake levels following the target curves during fall of 2025, the lake could accommodate that nearly five-foot rise in such a short time,” Senior Energy Analyst John Wasniewski said. “The potential for lower lake levels in the winter and early spring of 2027 may be especially noticeable compared to last year’s higher than normal winter elevations.”

Actual lake levels will depend largely on weather, snowpack, precipitation, runoff and other water conditions. National Weather Service has predicted Super El Niño conditions for the 2026-2027 winter. El Niño conditions in the Northwest have some correlation with warmer, drier winters.

The planned work is not expected to impact lake levels in the summer of 2027.

Since 1926, the lake has been required by license to operate between a maximum surface elevation of 1,100 feet and a minimum surface elevation of 1,079 feet. The most recent federal license established specific elevation targets throughout the year and requires Chelan County PUD to make every reasonable effort to balance seven operating objectives, including recreation, fish, flood control, erosion control, and tributary obstruction removal.

Chelan Valley customers are encouraged to monitor Chelan PUD’s lake levels website as forecasts change throughout the winter.