Hiram M. Chittenden Locks

Hiram M. Chittenden Locks. Why Are The Locks Needed?. When dedicated on July 4, 1917, the Hiram M. Chittenden Locks was the largest navigation facility in North America. During the dedication, the USS Roosevelt - flagship for Commodore Robert Peary's famous 1909 expedition to the North Pole - led a parade of boats through the locks., The locks control the elevation of the lakes behind the Hiram M. Chittenden Locks. This allows vessels to move back and forth from one water elevation to another. Notice how the water level of Puget Sound is lower than Salmon Bay. Freshwater of Salmon Bay meets the saltwater of Puget Sound at the locks. Depending on tides, there can be a 6-25 foot difference between fresh- and saltwater. We raise and lower water levels in the locks as needed to allow vessels to lock through., How do the locks work? Using chambers, gates, tunnels and valves, the lockmaster in the control tower opens and closes the large lock. Opening the miter gates allows vessels to enter the lock. The gates close after the vessel enters, creating a chamber. The lockmaster than opens and closes valves, allowing water to flow in and out of the lock through tunnels. , Think of the locks as a boat elevator. Water moves by gravity from a higher to lower level, no pumps are used. The average lockage takes about 7.5 million gallons of freshwater to fill the large lock.