Maps and drawings depicting aqueducts, watersheds, and filters in Philadelphia, including a design of Basin No.3 of the Belmont Reservoir, as well as the Perkiomen, Tohickon, and Neshaminy storage reservoirs. U.S. Geological maps in the collection include Pennsylvania, New York, Delware, and Massachusetts. Also, maps and diagrams of section tunnels, a profile of Schuylhill navigation, and consumption of water by private residents.