The Croton Aqueduct had to cross the Harlem River at some point, and the method was a major design decision. A tunnel under the river was considered, but tunneling technology was in its infancy at the time, and the uncertainty of pursuing this option led to its rejection. This left a bridge, with the Water Commission, engineers and the public split between a low bridge and a high bridge. A low bridge would have been simpler, faster, and cheaper to construct. When concerns were raised to the New York Legislature that a low bridge would obstruct passage along the Harlem River to the Hudson River, a high bridge was ultimately chosen.