Though long abandoned and removed from the Ohio River channel, the Davis Island Lock and Dam project continued to interest both engineers and historians at its centennial in 1985. Located about five miles downstream of the Point at Pittsburgh, it created a harbor for Pittsburgh extending up the Ohio and short distances up the Allegheny and Monongahela rivers on both sides of the Point. At its completion in 1885 it provided reliable year-round navigation and water supply along the Pittsburgh waterfront. By improving transportation and water supply in Pittsburgh's harbor, the lock and dam encouraged waterfront industrial development and thereby had incalculable but significant influence on the city's history. Because it was the first lock and movable dam built on the Ohio, it also influenced the regional history of the Ohio River basin and the experimental engineering used in its design and construction made it significant to the national and even international history of waterway engineering technology. The planning, design, and construction of the Davis Island project made it an engineering experiment of enduring import, a landmark in the annals of waterway technology. At Davis Island, the U. S. Army Corps of Engineers conducted some of its earliest hydraulic model studies and engaged in one of its first systematic studies of international waterways technology. Those planning studies resulted in the construction at Davis Island of the largest Chanoine dam built in the 19th century, of one of the earliest concrete structures built by the Corps of Engineers, of the first rolling lock gates, and of the largest navigation lock in the world at the time. Experimentation after completion of the lock and dam resulted in additional project modifications which improved its design and operational capabilities, with major improvements which were adopted at the locks and dams subsequently constructed. Accompanied by the Davis Island Lock and Dam portfolio, a reprint of 12 technical drawings, 42x52 cm., originally published in 1892 by the Chief of Engineers. The portfolio is filed in the Oversize area.