In 1842, water first entered the Croton Aquaduct at 5am from the Croton river, on its way to New York City. This massive public works project was undertaken to solve problems of the city’s inadequate water supply and to control diseases caused by contaminated wells. After initial planning of the route by Major David B. Douglass, the complex civil engineering task was executed from 1836 by John B. Jervis. Work began in 1837 on a horseshoe-shaped brick tunnel 7½-ft wide and 8½-ft high. As the landscape required, for 41 gently descending miles, it was bored through rock, cut into hillsides, or built as a covered conduit on more level ground. Valleys were crossed by embankments or massive arched bridges.«