Environmental Economics How does the combined sewer system contribute to water pollution in NYC area? Tsz Ying Liu Environmental Economics ECON 2505 Prof. Sean P. MacDonald 5/24/17

Combined Sewer System Built in mid-19th century Transfers rain water and untreated sewage waste to a wastewater treatment plants It overflows during heavy rainfall which causes Combined Sewer Overflow (CSO)

Combined Sewer Overflows Causes serious health issues The waste breaks down the dissolved oxygen that marine creatures need in order to survive Contains fecal bacteria that can make people sick and fish unhealthy to eat E. coli, Salmonella and Campylobacter

CSO

CSO

Stormwater Runoff Stormwater is rain water is runoff that channels into waterways It flows through many different locations and pick up many materials along the way, sometimes pollutants Problem: It end up in the sewer system and goes to the ocean along with pollutants

Bioswales Project A project that NYC works on to reduce stormwater runoffs Smart green infrastructure It collects data to inform city planning efforts Slow down the flow of stormwater; reduce the stress on sewer system

The Billion Oyster Project An operation to restore oysters and reefs to NYC harbor Started at NY harbor school by NY Harbor Foundation  Oysters filters 40 – 50 gallons per day Recycled 300,000 pounds of shell and restored 19.5 million oysters

Works Cited HWU Water Utility. (n.d.). Combined Sewer System. Retrieved May 23, 2017, from http://www.hkywater.org/departments/wastewater/combined-sewer-system NYC Department of Environment Protection. (n.d.). Types of Sewer Drainage Areas in New York City. Retrieved May 23, 2017, from http://www.nyc.gov/html/dep/html/stormwater/sewer_system_types.shtml Murphy, J. (2015, June 19). New York Confronts Polluted Past in its Waterways. Retrieved April 10, 2017, from http://citylimits.org/2015/06/19/the-cost-of-our-waternew-york-confronts-polluted-past-in-its-waterways/ NY Department of Environmental Conservation. (n.d.). Stormwater. Retrieved April 10, 2017, from http://www.dec.ny.gov/chemical/8468.html Chan, G. (2016, December 30). Stormwater in the City: How NYC is Addressing Urban Pollution Through Data.Retrieved April 10, 2017, from http://blog.durouas.com/2016/03/02/stormwater-in-the-city-how-nyc-is-addressing-urban-pollution-through-data/ NYC Department of Environment Protection. (n.d.). Bioswales and Stormwater Greenstreets . Retrieved May 23, 2017, from http://www.nyc.gov/html/dep/html/stormwater/bioswales.shtml Schiff, Y. (2016, July 28). How a Billion Oysters Are Set to Change New York’s Harbor. Retrieved April 25, 2017, from http://observer.com/2016/07/how-a-billion-oysters-are-set-to-change-new-yorks-harbor/