The Old Croton Aqueduct, which was completed in 1842, was a remarkable feat in engineering; its layout and construction served as the blue print for later projects such as the Catskills and Delaware Aqueducts. In the late eighteenth and early nineteenth century, residents of Manhattan realized the need for a clean and abundant water source for the rapidly growing city. Before the Croton Aqueduct was built, people relied on cisterns, wells and natural springs for sources of water. The faster the population of New York grew, the more scarce clean water became; often times the unsanitary public wells which were used by many New York residents would be the cause of various diseases. Most notably the outbreaks of Cholera and Yellow Fever during early 1800's were attributed to the lack of clean drinking water. As New York City's population grew, fires became increasingly common. The worst was the fire of 1835, which raged for three days because of an inadequate water supply to quench it. Lack of an efficient method of obtaining water made it difficult to deal with these fires, especially when most of the buildings in New York at the time were made out of wood. When the Croton Aqueduct was first completed in 1842, it consisted of a gravity fed aqueduct, approximately 40 miles long, a masonry dam on the Croton River, and two reservoirs in Manhattan. With the guidance of the chief engineer, John B. Jervis, the first phase of construction began in 1837; the 250 ft. wide and 55 ft. tall dam was built six miles upstream of the Croton River. The dam created a 5-mile long reservoir, which had the capacity to store 500 million gallons of water. The Old Croton Aqueduct was made of stone, brick and hydraulic cement, and was shaped like a horse shoe; it had the ability to transport up to 90 million gallons of water a day to New York. The aqueduct was linked to sixteen tunnels, all equipped with ventilators and weirs: the ventilators provided fresh air inside the tunnels, and the waste weirs allowed excess water to be discharged. To carry the water from the Croton Aqueduct into Manhattan, the High Bridge was constructed across the Harlem River valley; on this bridge two 36-inch diameter cast iron pipes carried the water into Manhattan. In 1861, a larger pipe, 90 inches in diameter was added to increase the carrying capacity of the piping. The piping was connected to two reservoirs in Manhattan: the York Hill Reservoir, and the Murray Hill reservoir. The York Hill Reservoir had the holding capacity of 150 million gallons, and was located at the current site of the Great Lawn in Central Park. The Murray Hill reservoir was situated at the current location of the New York Public Library, and had the capacity to hold 20 million gallons of water. When the construction of the Old Croton Aqueduct was finally complete, in July of 1842, no sounds of parades or celebration filled the streets of New York. However, on October 14th a gun salute sounded near City Hall Park, where for the first time, crystal clear water from the Croton Aqueduct gushed forth from a fountain in the park. The gun salute was followed by a parade and residents celebrated the completion of the Croton Aqueduct; it was a day off from work to commemorate the success of the aqueduct. New York City's population tripled between 1840's and 1870's prompting the city to plan for an expansion of the aqueduct system. The construction on the New Croton Aqueduct began in 1885 and was completed in July of 1890. The capacity of the New Croton Aqueduct tripled as a result of the expansion, and it could now carry up to 340 million gallons of water into New York City per day. To replace the High Bridge cast iron tubes, a seven-mile tunnel was drilled across the Harlem River using diamond drill. This tunnel descended approximately 300 ft. below the surface. In 1862 a new reservoir called Manhattan Lake was completed: it was located between 86th and 96th streets. The two remaining reservoirs, the Murray Hill and York Hill reservoirs were in use until 1899, and 1930 respectively. Three miles downstream from the original, a new dam called the Cornell Dam, was constructed to increase the capacity of the Croton watershed: the construction for the Cornell Dam began in 1892, and ended in 1906. In 1968, the Old Croton Aqueduct State Historic Park was created, and preserved many hiking trails in Westchester County, New York including the Old Croton Trial, which extends for 26.2 miles. In 1975, the American Society of Civil Engineers (ASCE) designated the Croton Water Supply system as a National Historic Civil Engineering Landmark.