OPEN SEWER ATLAS NYC A GIS EXPLORATION OF COMBINED SEWER INFRASTRUCTURE AND INTERVENTION STRATEGIES AT THE COMMUNITY SCALE
NYGEOCON 2015
Korin Tangtrakul
openseweratlas.tumblr.com
Project History – Red Hook BACKGROUND
COMBINED SEWER SYSTEM
70% About of the city’s sewershed
area is combined
WATER QUALITY IMPACT
SEWERSHED ISSUES
• Street flooding and
sewer backups
impacted the area.
• Through stakeholder
interviews, came to
realize these issues
were not isolated to
Hurricane Sandy!
HURRICANE SANDY – RED HOOK
• Data and maps on the
sewer system in Red
Hook was VERY
challenging to find.
RED HOOK SEWERSHED
• 311 complaints were
very easy to map and
showed consistent
sewer system issues.
CONSISTENT ISSUES IN RED HOOK
LACK OF DATA!
LACK OF DATA!
Open Sewer Atlas NYC is an
open data source for sewer
infrastructure and sub-
sewersheds or drainage areas
of interceptor sewer lines for
the priority sewersheds of
CSO-problem areas.
An exercise of GIS analysis to demystify New York City’s sewer system
WHAT IS OPEN SEWER ATLAS NYC?
Gowanus Newtown Creek Alley Creek Bronx River Jamaica Bay
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• To better understand the
sewer system, we looked at
issues at the “sewershed”,
“sub-sewershed” and
“CSO-shed” level.
RED HOOK SEWERSHED
OPENSEWERATLAS.TUMBLR.COM/MAP
FINAL PRODUCTS
DRAINAGE AREAS
311 COMPLAINTS
LANDUSE
FINAL PRODUCTS
OSANYC WORKSHOP
• Bushwick and
surrounding
neighborhoods
• 2,275 acres
• Almost 200,000
people
NCB-015
NEWTOWN CREEK OUTFALL
• 570 million gallons of CSO discharge enters
Newtown Creek from NCB-015.*
• 0.4 inches of rainfall is enough to overload the
system and result in a combined sewer overflow.*
*Sources Sampling Approach Memorandum, Remedial Investigation/Feasibility Study, Newtown Creek
NCB-015
• Almost 90% of the
area is impervious*
*Calculated using 2010 LiDAR model of land cover
NCB-015
• Water consumption is about 20 million gallons
a day (25 million gallons with air conditioning).*
*Calculated using 2014 CEQR Technical
Manual, and assuming residential
consumption of 75 gallons/person/day
QUANTIFYING CSO
• Stormwater runoff is about 70 million
gallons in a 1.2 inch storm.*
*Calculated using 2010 land cover, assuming .2 runoff coefficient
for grass/shrub, .3 for bare earth, .95 for buildings and roads, and
.85 for tree canopy and other (assumed to be mostly sidewalk).
These runoff coefficients were found in NYC DEP’s green
infrastructure guidelines, 2012. According to DEP, 90% of storms
are 1.2 inches or less.
QUANTIFYING CSO
• Mitigating 45 million gallons of
stormwater/wastewater in a 1.2 inch
storm may prevent CSO from NCB-015.* *Assumes the current capacity manages about .4 inches of rain, or 21.2 million gallons of stormwater runoff.
QUANTIFYING CSO
QUANTIFYING IMPACT
• CSOs 101
• Green Infrastructure Grants
• Build-your-own Downspout
Planter
WORKSHOP SERIES
QUESTIONS?