Dashields Locks and Dam is one of six major Pittsburgh District river facilities on the Ohio River. It is the only fixed crest type dam still in service on the Ohio River. This facility maintains the navigation pool for 7 miles from Glenwillard, PA, upriver to the Emsworth Locks and Dam near Pittsburgh. History Dashields was constructed from 1927-29 and opened for navigation in August 1929. It eliminated Lock and Dam 3, an old style wicket dam, which was built by the Corps from 1899-1907. The structure was named after David Shields, a member of a prominent local family and long-time postmaster of Old Sewickley Bottom in the 1800s. Project Information Dashields Locks and Dam consists of two lock chambers and a fixed crest dam, one of the major types in use. This dam is basically a concrete wall across the river which keeps the channel deep enough for navigation and for residential and industrial water supply users. Dashields averages about 550 commercial lockages every month, plus another 200 to 300 lockages of pleasure craft during the summer months.