Board of Water Supply. Joint exhibit by Board of Water Supply and Department of Water Supply, Gas and Electricity, "Mayor O'Dwyer presents Operation H2O: Welcome to Water Wonderland," at New York City's Golden Anniversary Exposition at Grand Central Palace which ran from August 23 to September 19, 1948. The celebration marked the 50th anniversary of the unification of the City of New York. September 16, 1948.