Skagit Hydroelectric Project, Newhalem, Wash. – Due to a decline in snow pack and rainfall in the Skagit basin, Seattle City Light is predicting water levels in the Ross reservoir at the utility’s Skagit Hydroelectric Project will be significantly lower than normal during the upcoming summer months. Ross reservoir and the surrounding Ross Lake National Recreation Area, administered by the National Park Service (NPS), will be open to visitors. However, the lower level of the lake will impact the availability of some visitor facilities, services, and recreational opportunities.
The typical pool elevation in July and August is between 1600 and 1602.5 feet. Currently, City Light estimates Ross Lake will be as much as 25 feet below those levels for the entire summer. The Skagit basin received only 4.4 inches of precipitation during February and March 2019, the driest March since 1992, compared to a 30-year average of 15.56 inches. Snow pack in the Skagit basin declined by 18% in March and was only 75% of normal (1992-2019) as of April 15.
Levels were further impacted by a need to release water from the reservoir to supplement flow in the Skagit River to protect Chum salmon redds. Tributary inflows to the Skagit River between Newhalem and Rockport were far below normal in March, requiring release of about 900 cubic feet per second (cfs) more water than normal to the river downstream of the Gorge Powerhouse throughout the month and into April. Higher than normal releases to the river will continue until June 7 or until tributary inflow increases.
At the predicted summer lake levels very few, if any, of the boat ramps and docks on the reservoir will be usable. Boaters should be aware of the increased risk of encountering submerged trees and logs. While trails along Ross Lake will be usable, there could be up to several hundred feet of exposed rock, dirt, and wood between the water and the normal shoreline at full pool. The extent of exposed lakebed in any given location is dependent on topography.