Also known as the Ballard Locks (pics), this complex set of locks just to the north of downtown Seattle was built by the Army Corps of Engineers and was opened on July 4, 1917. These locks are part of the Lake Washington Ship Channel that connects Lake Washington and Lake Union to the Puget Sound.
The locks serve three purposes:
- Maintain the water level of fresh water Lakes Union and Washington at 20 to 22 feet above sea level.
- Prevent the mixing of salt water from the Puget Sound with the fresh water from the lakes.
- Move boats from sea level to lake level and vice-versa.
The locks are still operated by the Army Corp of Engineers and boats are allowed to traverse them without paying a fee. There is a priority system that gives preference to military and commercial boat traffic ahead of pleasure craft.
The locks also incorporate a unique fish ladder where salmon transition from salt water to fresh water while making their way to their spawning grounds. The fish ladder has chambers where salt water and fresh water are mixed in which the fish linger for a while in order to make the adjustment.
On the grounds of the Ballard Locks there is also the Carl S. English Jr. Botanical Gardens. Carl English was a groundskeeper who began work on the site of the locks in 1931. At that time it was a typical barren military site with little adornment. He had no budget with which to purchase new plants so he began to correspond with botanists around the world and enlisted the assistance of ships captains who passed through the locks to help transport the plants and seeds. Over the years he constructed a splendid English landscape style garden of 7 acres with over 570 species and over 1,500 plant varieties from around the world. It is an unexpected bonus for visiting the locks.