Learn about water in urban areas

1. NYC Sewersheds: Our Urban Water Cycles
gil lopez
Fall 2020

2. Land Acknowledgement/Tribal Recognition
I acknowledge the Traditional Custodians of the land on which I live, work and play. In this, I
make you all aware that the issues and work I will discuss today refers to activities that have
and are taking place on the traditional lands of the Lenape Peoples. While colonization has
largely extirpated these peoples, I recognize their continuing connection to land, water and
community and I pay respect to Elders past, present and emerging. My intention today is that
this presentation will help bring honor and dignity back to lands and waters of Lenapehoking.

4. Sanitary/Separated
Sewer System

6. Discharge from
Combined Sewage Overflow
A combined sewer overflow (CSO) is the discharge from a
combined sewer system that is caused by snowmelt or
stormwater runoff. Combined Sewers are sewer systems that
collect stormwater runoff, domestic sewage, and industrial
wastewater in the same pipe and bring it to the wastewater
treatment facility. They are designed to overflow during wet
weather.
During rain events, when stormwater enters the sewers, the
capacity of the sewer system may be exceeded and the excess
water will be discharged directly to a waterbody (rivers, streams,
estuaries, and coastal waters)
There are currently 434 CSOs in NYC.

8. Clean Water Act
The Clean Water Act (CWA) establishes the basic
structure for regulating discharges of pollutants into the
waters of the United States and regulating quality
standards for surface waters. The basis of the CWA was
enacted in 1948 and was called the Federal Water
Pollution Control Act, but the Act was significantly
reorganized and expanded in 1972. "Clean Water Act"
became the Act's common name with amendments in
1972.
33 U.S.C. §1251 et seq. (1972)

9. Clean Water Act
The Clean Water Act (CWA) establishes the basic
structure for regulating discharges of pollutants into the
waters of the United States and regulating quality
standards for surface waters. The basis of the CWA was
enacted in 1948 and was called the Federal Water
Pollution Control Act, but the Act was significantly
reorganized and expanded in 1972. "Clean Water Act"
became the Act's common name with amendments in
1972.
33 U.S.C. §1251 et seq. (1972)
Because of combined sewage
overflow, NYC has never been in
compliance of the Clean Water Act

12. 14
Sewersheds
of NYC

14. About half of the City's land area is in separately sewered,
unsewered, or direct discharge areas. Of the sewered areas in
the city, about 40 percenthave separate storm sewers or direct
drainage, and the rest are served by the combined sewer sytem.

15. There are
434
Combined
Sewage
Overflows
In NYC

16. There are
434
Combined
Sewage
Overflows
In NYC
Some CSO outfalls discharge
pollution very infrequently or
in small amounts. Others
overflow practically every
time it rains,
dumping polluted
wastewater entering the
estuary. These 15 (out of 434)
CSO outfalls in the five
boroughs are responsible for
50% of the total volume of
CSO pollution that is
released each year.

17. So where does Your
Toilet Flush to?
In other words, what is your
"sewershed?" Every day, New Yorkers
discharge 1.5 billion gallons of liquid
waste into the sewer system, which
navigates 6,000 miles of pipe towards
two possible futures: decontamination at
a waste water treatment plant (WWTP) or
directly into our waterways as combined
sewer overflow (CSO).

18. In other words, what is your
"sewershed?" Every day, New Yorkers
discharge 1.5 billion gallons of liquid
waste into the sewer system, which
navigates 6,000 miles of pipe towards
two possible futures: decontamination at
a waste water treatment plant (WWTP) or
directly into our waterways as combined
sewer overflow (CSO).
… but it’s not
just your toilet
So where does Your
Toilet Flush to?

19. In other words, what is your
"sewershed?" Every day, New Yorkers
discharge 1.5 billion gallons of liquid
waste into the sewer system, which
navigates 6,000 miles of pipe towards
two possible futures: decontamination at
a waste water treatment plant (WWTP) or
directly into our waterways as combined
sewer overflow (CSO).
… but it’s not
just your toilet
Household Cleaners & Solvents
So where does Your
Toilet Flush to?

20. So where does Your
Toilet Flush to?
In other words, what is your
"sewershed?" Every day, New Yorkers
discharge 1.5 billion gallons of liquid
waste into the sewer system, which
navigates 6,000 miles of pipe towards
two possible futures: decontamination at
a waste water treatment plant (WWTP) or
directly into our waterways as combined
sewer overflow (CSO).
… but it’s not
just your toilet
Household Cleaners & Solvents
Commercial Waste

21. So where does Your
Toilet Flush to?
In other words, what is your
"sewershed?" Every day, New Yorkers
discharge 1.5 billion gallons of liquid
waste into the sewer system, which
navigates 6,000 miles of pipe towards
two possible futures: decontamination at
a waste water treatment plant (WWTP) or
directly into our waterways as combined
sewer overflow (CSO).
… but it’s not
just your toilet
Household Cleaners & Solvents
Commercial Waste
Industrial Waste

22. CSO Impacts
Discharge Water can contain high levels of suspended solids, toxic chemicals, floatable
material and other pollutants. Avoid contact while recreating within waterbodies with a
CSO during or following rain or snowmelt. CSO discharges can cause:
• Human and animal health hazards
• Water quality impacts
• Bathing beach closures due to bacterial contamination
• Aesthetic impacts due to floating debris or oil slicks
• Shellfishing bed closures
• Algae growth
• Reduced oxygen levels in the water

25. Lets Take a Look
http://www.newtowncreekalliance.org/combined-sewer-overflow/

27. Reducing CSOs
As part of the permittees long-term control plan, municipalities present
options to reduce the frequency and volume of CSO discharges. However
these options can be expensive and may be cost prohibitive for some
communities. Some options include:
• Separating stormwater and sewer lines
• Installing storage tanks to hold overflow during storm event
• Expanding wastewater treatment capacity
• Creating retention basins to hold overflow during storm events
• Screening and disinfecting the overflow
• Using green infrastructure to reduce stormwater flows
• Don’t use lots of water during a wet weather event

30. Cooking grease…wet
wipes…and lots of
other stuff…get flushed
down the sewers
creating fatbergs that
clog pipes and drain
wallets. You can keep
things running
smoothly by properly
disposing of these
items. Learn more at
fatbergfree.nyc.

33. Apply Compost
Compost is spongy and
absorbent. Mixing compost
into the first few inches of
soil aerates compacted
soils and greatly increase
the amount of water that
soils will absorb.

35. Grey
Infrastructure
Typically refers to traditional
infrastructure such as sewers,
tunnels, and wastewater treatment
plants. Expanding grey infrastructure
and making better use of existing grey
infrastructure enables us to store and
treat more stormwater runoff. This
reduces the occurrence of CSOs,
helping keep untreated sewage and
other pollutants out of our waterways.

37. Practices designed and constructed to manage stormwater
runoff when it rains. Green infrastructure slows down, absorbs,
and filters stormwater runoff before it can enter the sewer
system or local waterbodies. This helps reduce the occurrence
of combined sewer overflows and the amount of pollution
carried by stormwater runoff.

43. Blue Roof
Blue roofs are non-
vegetated source controls
that detain stormwater,
either releasing it more
gradually to the sewer
system or storing it for
beneficial reuse.

45. Thank You For Tuning In!