I have an article on Niagara Falls in the October volume of Environmental History. Here is a link to the article and an abstract: http://envhis.oxfordjournals.org/content/18/4/759.abstract
Over the first half of the twentieth century, Canada and the United States considered engineering works that would simultaneously divert water around Niagara Falls for hydroelectric production while ostensibly maintaining and enhancing the appearance of the great cataract. Binational studies and environmental diplomacy resulted in the 1950 Niagara Diversion Treaty, which authorized the International Niagara Control Works. The construction of these remedial works in the 1950s physically reconfigured Niagara Falls and the Niagara River immediately above the falls in order to divert water while masking the scenic effect of lower flow volumes. As a result, depending on the time of day, up to three-quarters of the Niagara River’s water does not go over the falls but is sent via massive tunnels to hydroelectric generating stations downstream. During debates in the following decades about further remedial works, public opinion helped stop some modifications of Niagara Falls, signifying a shift in attitudes. Using multiple archives from both countries, including the International Joint Commission, this study uncovers the conceptual and physical engineering of the Niagara landscape and waterscape in the middle decades of the twentieth century. The modern history of the manipulation of Niagara Falls highlights both shared and differing Canadian and American conceptions of the links between border waters, progress, technology, and nationalism.