The Croton Aqueuct or Old Croton Aqueduct was a large and complex water distribution system constructed for New York City between 1837 and 1842. The island of Manhattan, surrounded by brackish rivers, had a limited supply of fresh water available on the island, which dwindled as the city grew rapidly after the American Revolutionary War. Before the aqueduct was constructed, residents of New York obtained water from cisterns, wells, natural springs, and other bodies of water. But rapid population growth in the Nineteenth Century, and encroachment on these areas as Manhattan moved further North of Wall Street, led to the pollution of many local fresh water sources. The unsanitary conditions caused an increase in disease. Epidemics like cholera and yellow fever ravaged the city. The rapid expansion in densely-packed wooden buildings, combined with a lack of an adequate water supply, led to many fires, culminating in the 1835 Great Fire of New York, which destroyed large parts of the city.