Why is the lake so low? Why does Lake Chelan's water level change?

Why is the lake so low? Why does Lake Chelan's water level change?

Visiting beautiful Lake Chelan, enjoying the beaches and walking around Lake Chelan Riverwalk park might leave you wondering why the water is so low in the winter but higher in the summer. This seems like the opposite of what would be "normal" as far as 'mother nature' is concerned, so many may have the question, why? 

The Answer In Short: Lake Chelan and the Chelan River water levels are managed.

Why are the water levels managed?

"Lake Chelan is the reservoir for the Lake Chelan Hydro Project. Managing the level of popular Lake Chelan requires balancing seven objectives in the operating license that together provide recreation, protect fish, reduce erosion and restore year-round flows to the Chelan River." source: Chelan County PUD

About the operating licenese and management:

Lake Chelan water levels are managed by Chelan County PUD. The PUD last took a 50 year federal operating license for water level management in 2006. This federal license for managing the level of Lake Chelan requires balancing several objectives within the contract that provide recreation, protect fish, provide flood control, reduce erosion and restore year-round flows to the Chelan River.

History: There have been three contracts in history, the first in 1026, the second in 1981 and the most recent in 2006. Since 1926, the contract requires the district to hold the water level between 1,100 ft and 1,079ft, with some additional verbage added "which requires Chelan County PUD to make every reasonable effort to comply with seven operating objectives and seek to achieve May through October minimum target elevations, to the extent consistent with the objectives."

Has the establishment of the river ecosystem been beneficial to fish in Lake Chelan and the Chelan and Columbia Rivers?

"Yes. Since year-round flows have returned to the Chelan River and the Habitat Channel in the lower Chelan River has been developed, significant Chinook salmon and steelhead spawning and early rearing has been observed in the Habitat Channel through a rigorous monitoring and evaluation program. Additionally, significant resident fish use of species also inhabiting the Columbia River has been observed in the Habitat Channel. Continued minimum flows and the maintenance of habitat conditions provide an environment to achieve the Biological Objectives (salmon/steelhead spawning and rearing; resident fish use; etc.) described in the settlement agreement."  source: Chelan County PUD

Why does the water level change?

"Lake levels rise and fall naturally with seasonal changes due to the runoff in the tributaries to Lake Chelan and rainfall. The elevation of Lake Chelan is lower every fall and winter to make room for fall precipitation and spring runoff from mountain snowpack. The lake fills each spring at varying rates, depending on weather, snowpack and other conditions." source: Chelan County PUD

What factors that can affect lake level management?

  • High runoff due to a wet precipitation year
  • Early or late snow melt
  • Project operation and/or maintenance needs
  • Energy market conditions

Are the water levels guaranteed? 

No, managing the level of the lake is not an exact science. It involves a multitude of forecasts and calculations, with the added variable of weather including: snow pack in mountains, spring run off, rain, and daily temperatures.

Check lake levels any time at chelanpud.org.  Chelan PUD also offer a free app for checking lake levels right from your phone!

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