New York
The Croton Aqueduct was a large, complicated water works that was engineered between 1837 and 1842 to provide New York City with a steady supply of clean water. Before the aqueduct system, New Yorkers got their water from cisterns, wells, natural springs, and other bodies of water. The reasons for building the aqueduct were:
* the rapid population growth that took place during the 19th century
* a number of terrifying fires that destroyed large parts of the city, whose buildings were mainly made of wood.
* an increased demand for water for use in industry
* the existing water supply had become polluted and unsanitary, this contributed to an increase in disease and such epidemics as cholera and yellow fever.
The iron pipe encased in brick masonry was laid from the Croton Dam in northern Westchester County. It traveled over the High Bridge (the oldest of New York's great bridges at that time) that spanned the Harlem River at 173rd Street. It then went down the west side of Manhattan and into the Receiving Reservoir, which looked like a rectangular fortress, located in the area then known as "Yorkville," between 79th and 86th streets and Sixth and Seventh Avenues. Water flowed from the Receiving Reservoir to the Distributing Reservoir (also known as the Croton Reservoir), a similar fortification located on the site of what is now the New York Public Library at Fifth Avenue between 40th and 42nd streets. Clean water was distributed from there to homes and businesses in the lower parts of the city.
The Aqueduct opened in October 1842 and provided the city with water until 1940 when Robert Moses, Commissioner of Parks and Recreation, ordered it drained and filled to create the Great Lawn.

San Juan
The irrigation system (acequia) that provided the lands of the mission with fresh water, descended from the system that was also in use in Rome, the Middle-East and Central America. In Southern Texas they adopted the system too. The acequia was renovated and is nowadays providing a Spanish colonial demonstration farm with water. Please click for more information on Espada.