A two-thousand-square-mile group of watersheds north of New York City provides 8 million city residents with clean, delicious drinking water. Although this water is treated with chlorine, most of it is unfiltered.
Most U.S. cities must filter their drinking water for safety. But in 1997, the U.S. EPA exempted New York from building expensive filtration plants for its Delaware and Catskill reservoirs. That’s because of the city’s efforts to protect its drinking water at the source. Through a hard-fought agreement between the city and upstate communities, there are limits on construction and on agricultural activities that could add contaminants to the watershed. New York City has also purchased and protected sensitive lands in the watersheds.
Arriving at this arrangement was not without controversy, as some New York listeners may recall. But it is a prime example of what we call ecosystem services, in which natural systems do work that has tangible, economic benefits. Forests surrounding rivers and streams in the less densely populated upstate regions help protect the water quality. Stands of trees and marshes on the edges of water bodies filter out contaminants.
By protecting these forests and wetlands, New York has been able to avoid spending billions of dollars on filtration plants, something that most municipalities were required to do years ago. It has not had a single outbreak of waterborne diseases like giardia or cryptosporidium. It is unclear how long New York can continue this record, because development pressure continues in the watershed. But for fifteen years, nature has provided an enormously beneficial service to New York City.
Photo, taken on February 15, 2011, courtesy of Allie Holzman via Flickr.