Current Reservoir Levels - Updated January 17, 2025
Cascade today announced it will begin the spring refill of the Lake Tapps Reservoir on or around March 15. Cascade typically begins refill in mid-February, but a joint U.S. Army Corps of Engineers (USACE)/Cascade construction project has an unforeseen delay impacting Cascade’s ability to divert water from the White River for refill. While the exact timing is subject to construction progress, USACE and Cascade believe that the refill will begin approximately March 15.
“We understand the sensitivity surrounding timing of lake levels and are working diligently with the Cascade Water Alliance to complete this phase of the project, which will allow the White River to refill Lake Tapps,” said Col. Kathryn Sanborn, commander of Seattle District, USACE. “This project will benefit both USACE and the Lake Tapps community.”
This project will replace a 100-year-old infrastructure with a new diversion structure that will improve water diversion reliability and water quality for the reservoir. It is part of a broader USACE project designed to improve the fish passage at Mud Mountain Dam. The delayed phase of the project will improve the flow of sediment in the White River and will provide a new diversion structure for Cascade.
Cascade draws the reservoir level down during the winter for dike stability and maintenance activities. This winter Cascade held the reservoir level at a slightly higher level than usual to support refill efforts in the spring.
Cascade maintains seasonal recreational water levels between elevation 541.5 feet and 543 feet from April 15 to September 30. Cascade is hopeful it can reach a reservoir level of 541.5 feet by April 15. However, construction progress and instream flows in the White River will impact the exact timing. Cascade’s state water rights and agreements with the Lake Tapps Community Council, the Muckleshoot Indian Tribe, and the Puyallup Tribe of Indians only allow Cascade to divert water from the White River to the reservoir when the water in the river is above a certain level called “instream flows.”
Cascade will update the community as additional information is available. Residents can monitor overall reservoir water levels by clicking here.
As a reminder, if residents are planning work on their property, they should obtain the appropriate, required permits from the appropriate federal, state, and local agencies and a Cascade license prior to beginning any work. Further, residents should keep in mind as they do work on their property, especially bulkheads, that Cascade has the authority to raise reservoir levels to elevation 543 feet under current water rights, so any new or modified bulkheads should be built with the consideration that the reservoir level will be up to 543 feet. Cascade raises the reservoir to 543 feet once a year so that residents know where the water level is on their property.
For more information about Cascade and Lake Tapps visit www.cascadewater.org and for information regarding licenses for project work visit http://cascadewater.org/lake_tapps_licenses_and_permits.php
USGS Links:
General Reservoir Level Management
Cascade has owned and operated the Lake Tapps Reservoir since 2009. During that time, Cascade has managed lake levels in accordance with the provisions of the Lake Tapps Reservoir Water Rights, which incorporate relevant provisions from the 2009 Agreement regarding Lake Tapps between Cascade Water Alliance and the Lake Tapps Community and the 2008 White River Management Agreement between the Puyallup Tribe of Indians, the Muckleshoot Indian Tribe and Cascade Water Alliance.
The Water Rights and the agreements provide for Cascade to maintain recreational reservoir levels or normal full pool, between elevation 541.5′ and 543.0′ (gage height) from April 15 through Sept. 30.
Typical fall drawdown to a lake level of approximately elevation 538′ – 539′ is sufficient to protect the integrity of the Lake Tapps dikes and for any routine inspections. This minimizes the wear on the valves in the power house during fall drawdown and the risk of problems refilling the Lake Tapps Reservoir during periods of water shortage.
Specific dike or other maintenance projects will require Cascade to reduce the lake level in the fall and winter to approximately elevation 533′ to 535′ (some projects may require the level to be lower).
