The U.S Army Corps of Engineers says because of the drought, the official water level in Lake Union, Lake Washington, the Ship Canal and connected waters is already nearly two feet below the spring peak in April.
It is now forecast to drop about another foot before fall rains kick in. That’s a three foot drop. A four foot drop would exceed the official record low set back in 1958 of 18.3 feet. That’s the height above mean sea level when the locks were completed in the early 1900s.
Because of conservation measures, the Corps does not expect to meet or exceed the old record, even though this is considered a record drought for the state.
The Corps of Engineers tries to keep the lake within a two-foot range. But levels are set to exceed that range because the amount of rainfall and runoff coming into the lake won’t match the amount of water evaporating and the water needed to run the locks in Ballard.
Conservation measures have been in place since spring, including an increased reliance on the smaller of the two locks and filling those locks with as many boats as possible. Waits for pleasure boats at the locks can run up to an hour.
For the Washington State Department of Transportation, the lake level would have to drop six feet or more before the floating bridges would be impacted. But Seattle’s large houseboat community could be at greater risk, particularly homes floating near shore.
Amalia Watson with the Seattle Floating Homes Association says early warnings from the Corps of Engineers has helped mitigate the impacts. There are concerns over stress to docks and utility lines that supply water and gas, and drain away sewage. – King 5.com