You can view current data for Lake Washington levels at the USACE Website here (in left sidebar click on Lake Washington / Lake Washington Elevation). The current USACE contact is Nicole L. Celestine 206-554-1894 nicole.l.celestine@usace.army.mil if you have any questions. Read the April 30th press release explaining why USACE is raising the lake a month early here.
There is a database with historical data: here (search LWSC) and a general website for Lake Washington Ship Canal here.
USACE typically maintains the water level between 20 and 22 feet as measured officially at the Hiram M. Chittenden Locks. Corps officials keep winter water levels at 20 feet, and begin the annual summer refill in February, targeting a 22-foot elevation by late May to early June. The higher level helps meet summer water use requirements, providing water necessary for fish passage, navigation, and salinity control. Water is slowly consumed throughout the summer, until it reaches the winter level typically in early December. While the lake is rising, vessel owners should closely monitor lake elevations and adjust mooring lines as necessary. Fill rates and target elevations vary through May based on conditions. The record low lake level is 18.35 feet, reached in 1958. The lowest recent recorded water level below 20 feet was 19.91 feet, measured in August 2015.
The 22-foot target elevation is referenced to the local project datum, equivalent to 18.75 feet referenced to the North American Vertical Datum of 1988. Lake Washington and Lake Union levels may vary due to natural gradient between the lake and the locks, or wind that can push the lake levels up for short durations. More information on Lake Washington’s status is available on the Corps’ Seattle District Reservoir Control Center website here.
Members of the FHA Board met with Logan Osgood-Zimmerman, Senior Water Manager with the Seattle District Corps of Engineers to better understand how the water level is managed by USACE. You can view her presentation below.
For more information about activities at the Locks, visit the Locks’ Web site here. Also, follow the Locks on Facebook here and Twitter here. The chart below shows the annual cycle.
8.15.2018 – Email from William Dowell, Public Affairs Office, Seattle District, U.S. Army Corps of Engineers The lake elevation is at 20.46 feet, above the 20 foot minimum target, but certainly on the low side for mid-August. The current elevation reflects how dry and hot it has been and how low inflows are to Lake Washington. In terms of projections, our water manager thinks there is about a 50 percent chance the lake will drop slightly below 20 feet later this summer. The most likely scenario is .1 or .2 feet below, which is essentially only a couple inches.
It is not as concerning as 2015 was, but we recognize any dip below 20 feet causes concerns in the floating home community. It would be beneficial if the floating home community not consider 20 feet the minimum it will ever go. In any given year there is about a 30 percent chance the lake could go below the minimum target elevation. The Corps of Engineers is not required to keep it at, or above 20 feet. The water manual allows for variation. Having said that, we do not want or plan to go below the 20-foot target, but there is a chance every year. Please feel free to call or email if you would like more information.
Sincerely, William Dowell, Public Affairs Office, Seattle District U.S. Army Corps of Engineers
Work: 206.764.3464 | Cell: 206.300.4177 | william.r.dowell@usace.army.mil
U.S. Army Corps of Engineers officials will begin Lake Washington’s annual summer refill operations February 15, 2018. Vessel owners should closely monitor lake elevations and adjust mooring lines as necessary. Water managers are targeting a typical annual refill of the lake to elevation 22 feet this spring. Fill rates and target elevations vary through May based on conditions. Refilling the lake to 22 feet will help meet increased summer water use, providing water necessary for fish passage, navigation and salinity control. Private and commercial maritime interests along Lake Washington Ship Canal and in Lakes Washington and Union should expect a gradual rise from the winter level of 20 feet until the 22-foot target refill elevation is reached around June 1. The official lake level is measured at the Locks. The 22-foot target elevation is referenced to the local project datum and is equivalent to 18.75 feet referenced to the North American Vertical Datum of 1988. Lake Washington and Lake Union levels may vary due to the natural gradient between the lake and the locks or wind that can push the lake levels up for short durations. Depending on conditions, the lake may remain at the maximum target elevation through June and July. More information on Lake Washington’s status is available on the Corps’ Seattle District Reservoir Control Center website at http://bit.ly/NWS-RCC. For more information about activities at the Locks, visit the Locks’ Web site at http://bit.ly/BallardLocks. Also follow the Locks on Facebook www.facebook.com/ChittendenLocks and Twitter, www.twitter.com/ChittendenLocks
Contact: Bill Dowell – (206) 764-3464 – william.r.dowell@usace.army.mil
1.9.18 – Email from William Dowell, Public Affairs Office, Seattle District, U.S. Army Corps of Engineers
I just reviewed the Lake Washington elevation data and the current elevation is right on point and has been since December 1. Typically the elevation is at 20 feet (officially measured at the Locks) and around February 15 we begin Summer refill. We gradually refill the lake reaching 22 feet around May. The Water Manager, working with Locks officials, gradually use that water throughout the Summer, reaching 20 feet around December 1. The Summary Hydrography gives good minimum, mean, and average.Water elevations can be viewed on our public website at: http://www.nwd-wc.usace.army.mil/nws/hh/www/index.html#, then clicking on Lake Washington Ship Canals and Lake Washington Elev. Again, we have been hovering right at 20 feet since December 1, which won’t change until around mid-February. We do appreciate the floating home owners and consider them a valued stakeholder. If anyone has questions or concerns we’re happy to answer them. Sincerely, William Dowell, U.S. Army Corps of Engineers, Work: 206.764.3464, Cell: 206.300.4177
6.19.2017 – Email from William Dowell, Public Affairs Office, Seattle District, U.S. Army Corps of Engineers
The Lake Washington elevation is currently at 21.97 feet, as measured at the Locks. This is considered full pool of 22 feet. We have been at this elevation since around June 1. Spillway gates are being used to prevent the forebay (the lake side) elevation from exceeding 22 feet.
We are in the annual involuntary draft operations period, where the lake has begun water use that usually exceeds inflows. The weather this year has provided more water than typical and as such the forebay elevation is still hovering at the 22-foot mark. Corps water managers are monitoring to prevent it from rising past 22 feet and expect the elevation to begin dropping soon. I hope the information is helpful. Please let me know if you need anything else.
Sincerely, William Dowell, U.S. Army Corps of Engineers, Work: 206.764.3464, Cell: 206.300.4177
7.27.2016 – Email from William Dowell, Public Affairs Office, Seattle District, U.S. Army Corps of Engineers
What is boils down to is you haven’t heard from us because there is nothing to report, no news is good news. As of today, Lake Washington’s level is about half a foot higher than the same day last year. That 6 inches means a lot and really the differences have been, we’re getting some rain and the cooler temperatures.
I can assure you we’re still keeping an eye on things — having monthly meetings, looking at forecasts and verifying operating procedures. Even though we initially had concerns, the weather has been cooperating. We understand and value the floating home community as a stakeholder and I will continue to communicate to you. Bill Dowell.
5/4/2016 Army Corps Raising Lake Washington to Summer Elevation Early
Posted 5/4/2016. Release no. 16-012 from the U.S. Army Corps of Engineers
Contact – Bill Dowell on 206-764-3464 or william.r.dowell@usace.army.mil
After a really good start, the lake is currently at elevation 21.8 feet, typical for early May and consistent with normal annual operations. However, because of recent dry conditions and forecasts, and significantly earlier than normal snowmelt, Corps water managers intend to complete refill by mid-May instead of the usual June 1 target date.
“If we wait until late May, there may not be sufficient lake inflow to get us to elevation 22 feet,” said Ken Brettmann, senior water manager with the Seattle District, U.S. Army Corps of Engineers.
Getting the lake to 22 feet is extremely important since every inch of water in the 2-foot operating band is needed for fish passage, lockages, and managing water quality throughout the season.
Refilling early last year helped immensely during the record-breaking drought but Corps officials still needed to alter lock operations. Even with the operational changes of the early refill, limiting water usage for smolt flumes, maximizing lockage efficiency and delaying lockages, the lake briefly fell below the 20 foot minimum elevation water managers try to maintain.
“Last year’s challenging drought conditions reinforced how important it is to fill the lake to the 22 foot elevation each year,” said Brettmann.
Depending on conditions, the lake may remain at full pool through June. The official lake level is measured at the Locks. Lake Washington levels may vary due to the natural gradient between the lake and the locks or wind that can push the lake levels up for short durations.
Vessel owners should closely monitor lake elevations and adjust mooring lines as necessary.
More information on Lake Washington’s status is available on the Corps’ Seattle District Reservoir Control Center website at http://bit.ly/NWS-RCC.
Ballard Locks Chittenden Locks drought Lake Washington Lake Washington Ship Canal U.S. Army Corps of Engineers
