STATE OF THE SEWERS 2016 - New York · PDF fileBill de Blasio Mayor Vincent Sapienza, P.E....

Bill de BlasioMayor

Vincent Sapienza, P.E. Acting Commissioner

STATE OF THE SEWERS 2016Performance MetricsFiscal Year 2016 (July 1, 2015 through June 30, 2016)

Catch Basin Cleaning

STATE OF THE SEWERS • 2016

New York City Department of Environmental Protection

TABLE OF CONTENTS

INTRODUCTION .........................................................................................................................................................................................................................................................................3

THE SEWER SYSTEM ..............................................................................................................................................................................................................................................................4

CEASE THE GREASE ................................................................................................................................................................................................................................................................5

PERFORMANCE METRICS .................................................................................................................................................................................................................................................6

Citywide .............................................................................................................................................................................................................................................................................................7

Sewer Backup and Catch Basin Resolution Time ..................................................................................................................................................................................................8

Bronx .....................................................................................................................................................................................................................................................................................................9

Brooklyn .......................................................................................................................................................................................................................................................................................... 10

Manhattan ..................................................................................................................................................................................................................................................................................... 11

Queens ............................................................................................................................................................................................................................................................................................. 12

Staten Island ................................................................................................................................................................................................................................................................................. 13

3



INTRODUCTIONThe New York City Department of Environmental Protection (DEP) protects public health and the environment by supplying clean drinking water, collecting and treating wastewater, and reduc-ing air, noise, and hazardous materials pollution. To achieve this mission, DEP operates and main-tains 7,500 miles of sewers that convey an aver-age of 1.3 billion gallons of wastewater per day to 14 in-city wastewater treatment plants.

Over the last decade, DEP has embraced a data-driven, proactive approach to operating and maintaining the sewer system. By using a range of digital tools and innovative practices, DEP develops targeted programs to provide a high level of service to our customers while focusing on investments that will prioritize our resources.

Staten Island Bluebelt

4



DRAINAGE TYPE

SEPARATE

COMBINED

OTHER

BLUEBELT

THE SEWER SYSTEMApproximately 60% of New York City’s sewer sys-tem is combined, handling sanitary waste from both homes and businesses as well as storm water. The other 40% of the sewer system is separated – sanitary sewers carry sewage to the treatment plant, while storm sewers carry storm water runoff in a separate pipe directly to a local waterway.

In wet weather, wastewater treatment plants that receive combined flow can treat up to twice the designed dry weather flow. However, to eliminate flooding from roadways, the capacity of the city’s sewer system is greater than that of the plants. When the plants reach their capacity at twice dry weather flow, regulators release the excess flow from the sewers into the harbor as combined sewer overflow to protect against sewage back-ing up into homes and businesses.

Sewers vary in size; however, all sewers are de-signed to convey wastewater through the system at a speed fast enough to minimize the deposi-tion of debris and sediment in the pipes but slow enough to minimize scouring and erosion. DEP targets its programs and resources to ensure the system continues to operate as designed and to maintain the system in a state of good repair.

To learn more about how DEP’s sewer system functions, click here.

http://www.nyc.gov/html/dep/html/wastewater/index.shtml

5



Door-to-Door Outreach Campaign to Visit 50,000 Homes in Southeast Queens to Encourage Residents to Properly Dispose of Grease and Help Reduce Sewer Backups

CEASE THE GREASENew York City needs the help of all of its residents to keep our sewer system running properly. Cooking oil and grease are wastes that the City’s sewer system cannot handle and should not be discarded down the drain. Grease can cling to the insides of pipes and the sewer system, building up and even-tually blocking pipes completely. If wastewater can’t move freely through pipes and out into the sewer system, it can back up into your home and can cause unsanitary conditions and damages that can be expensive to repair. To learn how to properly dispose of grease, click here.

http://www.nyc.gov/html/dep/html/residents/congrease.shtml

6



PERFORMANCE METRICSDEP uses a variety of metrics to evaluate our operations across the agency, from frontline supervisors to senior management. This data-driven approach allows us to focus our resources, develop targeted programs, and provide the highest level of ser-vice to our customers. All annual performance metrics in this report correspond to fiscal years. For example, Fiscal Year 2016 began July 1, 2015 and ended June 30, 2016.

Sewer Backup ComplaintsWhen our field crews respond to a customer call about a potential sewer backup, they first open manholes around the area where the backup or blockage is reported. If the sewer segment has higher than expected wastewater levels, the crew will note this as a “confirmed sewer backup” whether or not any backups occur. If a crew does not detect higher wastewater levels than expected, it is noted as an “unconfirmed sewer backup.”

Recurring Confirmed Backup ComplaintsThe sewer system is divided into 160,000 “sewer segments” that run between two adjacent manholes. In order to identify systemic issues, DEP tracks street segments with recurring confirmed sewer backups (multiple backups on the same segment in the same year) during both dry and wet weather.

Sewer CleaningProactive sewer cleaning includes miles of sewers cleaned as part of the inspection and analysis programs, regular sewer maintenance program, and the Department of Design and Construction inspection and cleaning. Sewer cleaning activities in re-sponse to a 311 complaint are categorized as “Reactive” cleaning

Confirmed Sewer Backup CausesAfter visually inspecting affected sewer segments, crews identify and record the po-tential cause of a confirmed sewer backup.

• “Grease” refers to the buildup of fats, oils, and grease in a sewer.

• “Debris” refers to sand, silt, and roadbed aggregate that accumulate along the bot-tom of the sewer.

• “Heavy Rain” refers to microbursts and other brief, heavy rainstorms that can tem-porarily overtax the sewer.

• “Other” includes backups where conditions warranted further investigation.Sewer Flushing

7



DEP’s extensive and robust sewer inspec-tion, analysis and cleaning program contin-ues to net significant improvements across all key performance indicators citywide.

Total sewer backup complaints have fallen 25% since FY2012, and confirmed sewer backup complaints have fallen 49% over the same period.

The number of street segments with re-curring confirmed sewer backups has de-creased by 50% since FY2012. The number of street segments with recurring confirmed dry weather sewer backups also decreased by 47% since FY2012.

In FY2016, 71% of backups were related to grease; 16% attributed to debris; 8% attrib-uted to heavy rains and 5% due to other causes.

Systematic, proactive sewer cleaning has in-creased by 133%, while reactive sewer clean-ing has decreased by 67% from FY2012.

CITYWIDE

0

300

600

900

1,200

2012 2013 2014 2015 2016

Segm

ents

Fiscal Year

Recurring Confirmed Backup Segments

0

300

600

900

2012 2013 2014 2015 2016

Segm

ents

Fiscal Year

Recurring Confirmed Dry Weather Backup

Segments with Recurring Dry Weather SBUs

02,0004,0006,0008,000

10,00012,00014,00016,000

2012 2013 2014 2015 2016

spukcaB reweS

Fiscal Year

UnconfirmedConfirmed

Sewer Backup Complaints


Other5%

HeavyRain 8%

Debris16%

Grease71%

FY16 Confirmed Sewer Backup Causes

Citywide Sewer Backup Causes

0100200300400500600700

2012 2013 2014 2015 2016M

iles

Reactive Proactive

Sewer Cleaning Miles

Fiscal Year

Sewer Cleaning

Segments with Recurring SBUs

8



New York City has more than 148,000 catch basins to col-lect storm water runoff from streets and sidewalks. DEP’s rigorous sewer and catch basin inspection, analysis, and cleaning program has produced improvements in the level of sewer service citywide.

Over the past five years, the time to resolve sewer-related issues has fallen significantly.

Sewer backup resolution times have fallen from a 2012 high of 5.59 hours to 3.7 hours in 2016 – a 33% total reduction.

Similarly, catch basin-related complaint resolution times have fallen from 5.05 days in 2012 to 3.75 days in 2016, a 26% total reduction.

SEWER BACKUP AND CATCH BASIN RESOLUTION TIME

0

2

4

6

8

2012 2013 2014 2015 2016

Hour

s

Fiscal Year

Sewer Backup Resolution Time

Avg Res Time Target (7 hours)

0

2

4

6

8

10

2012 2013 2014 2015 2016

Days

Fiscal Year

Catch Basin Complaint Resolution Time

Avg Res Time Target (9 days)

Sewer Backup Resolution Time

Catch Basin Complaint Resolution Time

9



BRONXOver the past five years, total sewer back-up complaints have increased 8%, but confirmed sewer backup complaints have fallen 53%.

Since FY2012, the number of street seg-ments with recurring confirmed sewer backups has decreased by 50% and the number of street segments with recurring confirmed dry weather sewer backups de-creased by 63%.

In FY2016, 89% of backups were attributed to grease; 5% to debris; and 6% attributed to heavy rains and other factors.

Reactive sewer cleaning has decreased by 44% from FY2012. The drop in reactive cleaning is due to the continued decline in the number of confirmed sewer backups.

0200400600800

1,0001,2001,400

2012 2013 2014 2015 2016

spukcaB reweS

Fiscal Year

Unconfirmed

Confirmed


Other6% Debris

5%

Grease89%



Sewer Backup Causes

05

101520253035

2012 2013 2014 2015 2016

Segm

ents

Fiscal Year

Recurring Confirmed Backup SegmentsRecurring Backup Segments

0

5

10

15

20

25

30

2012 2013 2014 2015 2016

Segm

ents

Fiscal Year

Recurring Confirmed Dry Weather Backup SegmentsRecurring Dry Weather Backup Segments

05

1015202530354045

2012 2013 2014 2015 2016M

iles

Reactive Proactive


Fiscal Year

Sewer Cleaning

10



BROOKLYNSince FY2012, total sewer backup com-plaints have fallen 29% and confirmed sew-er backup complaints have fallen 52%.

Over the past five years, the number of street segments with recurring confirmed sewer backups has decreased by 57% and the number of street segments with recur-ring confirmed dry weather sewer backups decreased by 56%.

In FY2016, 50% of backups were attributed to grease; 28% attributed to debris; and 22% attributed to heavy rains and other factors.

Systematic, proactive sewer cleaning has in-creased by 153% while reactive sewer clean-ing has decreased by 69% from FY2012. The drop in reactive cleaning is due to the con-tinued decline in the number of confirmed sewer backups.

0

1,000

2,000

3,000

4,000

5,000

6,000

2012 2013 2014 2015 2016

spukcaB reweS

Fiscal Year

Unconfirmed

Confirmed


0

50

100

150

200

250

300

350

2012 2013 2014 2015 2016

Segm

ents

Fiscal Year


020406080

100120140160

2012 2013 2014 2015 2016M

iles

Reactive Proactive


Fiscal Year

Other 5%

Heavy Rain 17%

Debris28%

Grease50%

Confirmed Sewer Backup CausesFY16 Confirmed Sewer Backup Causes

020406080

100120140160180200

2012 2013 2014 2015 2016

Segm

ents

Fiscal Year

Recurring Confirmed Dry Weather Backup Segments


Sewer Backup Causes

Recurring Backup Segments

Recurring Dry Weather Backup Segments

Sewer Cleaning

11



MANHATTANSince FY2012, total sewer backup com-plaints in Manhattan have fallen 35% and confirmed sewer backup complaints have fallen 55%.

Over the past five years, the number of street segments with recurring confirmed sewer backups has decreased by 54%, and the number of street segments with recur-ring confirmed dry weather sewer backups decreased by 50%.

In FY2016, 50% of all backups were attrib-uted to grease; 32% to debris; and 18% at-tributed to heavy rains and other factors.

Systematic, proactive sewer cleaning has in-creased by 86%, while reactive sewer clean-ing has decreased by 13% from FY2012. The drop in reactive cleaning is due to the con-tinued decline in the number of confirmed sewer backups.

0100200300400500600700800

2012 2013 2014 2015 2016

Sew

er B

acku

ps

Fiscal Year

Unconfirmed

Confirmed


05

1015202530354045

2012 2013 2014 2015 2016

Segm

ents

Fiscal Year


0

5

10

15

20

25

2012 2013 2014 2015 2016M

iles

Reactive Proactive


Fiscal Year

HeavyRain8%

Debris32%

Grease50%


Other10%

0

5

10

15

20

25

30

2012 2013 2014 2105 2016

Segm

ents

Fiscal Year



Sewer Backup Causes



Sewer Cleaning

12



QUEENSIn Queens, total sewer backup complaints have fallen 18% and unconfirmed sewer backup complaints have fallen 40% since FY2012.

Over the past five years, the number of street segments with recurring confirmed sewer backups has decreased by 37%. The number of street segments with recurring confirmed dry weather sewer backups de-creased by 34%.


Systematic, proactive sewer cleaning has in-creased by 614% while reactive sewer clean-ing has decreased by 64% from FY2012. The drop in reactive cleaning is due to the con-tinued decline in the number of confirmed sewer backups.

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

2012 2013 2014 2015 2016Fiscal Year

Unconfirmed Confirmed


Sew

er B

acku

ps

050

100150200250300350400450500

2012 2013 2014 2015 2016

Segm

ents

Fiscal Year

Recurring Confirmed Backup Segements

0

50

100

150

200

250

300

350

2012 2013 2014 2015 2016M

iles

Reactive Proactive


Fiscal Year

Other 5%

Heavy Rain1%

Debris6%

Grease88%


0

50

100

150

200

250

300

2012 2013 2014 2015 2016

Segm

ents

Fiscal Year



Sewer Backup Causes



Sewer Cleaning

13



STATEN ISLANDSince FY2012, total sewer backup com-plaints have fallen 47% and confirmed sew-er backup complaints have fallen 61%.

Over the past five years, the number of street segments with recurring confirmed sewer backups has decreased by 69% and the number of street segments with recur-ring confirmed dry weather sewer backups decreased by 67%.


Systematic proactive sewer cleaning has in-creased by 30% while reactive sewer clean-ing has decreased by 60% from FY2012. The drop in reactive cleaning is due to the con-tinued decline in the number of confirmed sewer backups.

0

500

1,000

1,500

2,000

2,500

2012 2013 2014 2015 2016

Sew

er B

acku

ps

Fiscal Year

Unconfirmed

Confirmed


020406080

100120140160180

2012 2013 2014 2015 2016

Segm

ents

Fiscal Year


0

20

40

60

80

100

120

140

2012 2013 2014 2015 2016M

iles

Reactive ProactiveFiscal Year

Other5%

Debris27%

Grease50%


Heavy Rain18%

0102030405060708090

2012 2013 2014 2015 2016

Segm

ents

Fiscal Year



Sewer Backup Causes



Sewer Cleaning

Bill de BlasioMayor

Vincent Sapienza, P.E. Acting Commissioner

STATE OF THE SEWERS 2016 - New York · PDF fileBill de Blasio Mayor Vincent Sapienza, P.E....

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