In Shokan turn on to Reservoir Road, for a firsthand glance of New York City's water supply. Continue across the bridge dividing the Ashokan Reservoir for panoramic views of a Catskills Shandaken range. This road continues to the Route 28-A loop, where you can park on either side of the dam, to walk or bike a 2-mile scenic promenade. No one knows the story of New York's reservoirs like Diane Galusha - communications director and education coordinator at the Catskill Watershed Corporation. We hiked with her along Birch Creek in the Shandaken Wild Forest. Diane Galusha: This stream makes its way to the Esopus Creek, and the Esopus Creek is what was dammed to create the Ashokan reservoir. So this water, assuming it isn't drunk by a deer or a porcupine and isn't evaporated, eventually gets to New York City. Our task really is basically to keep New York's water clean. We are the stewards of the water for half of New York state's population. New York gets about 1.2 billion gallons of water a day, about a billion gallons or so from the Catskills. New York City's water supply is the largest unfiltered water supply in the country. There are a few others, but this is by far the biggest. The story of New York City's Catskill water supply goes back to the turn of the 20th century, when 26 entire communities were displaced to make way for a network of reservoirs. Diane Galusha: For the most part, all of the homes and the barns and the businesses and the churches and schools and the community centers were destroyed. They basically removed all traces of habitation, and all traces of vegetation. They cut down all the trees and a couple inches of the ground; filled in all the foundations and the privy holes and all that, and created something of a wasteland before they opened the gates of these cofferdams and let the water rise and cover the sites of those communities which really are kind of ghost towns beneath the waters now. The early reservoirs were built largely by immigrants. Those immigrants were housed in large labor camps. Incredibly tedious, incredibly labor intensive, and incredibly dangerous. Many people died, people lost limbs. This water that we're sitting next to is eventually going to be coming out of somebody's kitchen faucet. It's getting there strictly by gravity. This took a lot of thought, foresight, a lot of incredible engineering, by a lot of very brilliant people, and a lot of very hard work. And lives from many, many workers over generations. There are a lot of people that we owe thanks to who gave up a lot so that New York City could have water.