Greening Mass Transit & Metro Regions: The Final Report - MTA

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Groundwater: From Old Nuisance to New Resource
Like many subway systems, the MTA spends energy pumping
groundwater out of tunnels, up to 8 million gallons per
day on dry days. Once a nuisance, this water should be
regarded as a valuable resource for thermal-exchange cooling
and heating, washing vehicles and other non-potable uses.
Typical Subway Drainage and Pumping System
Rainwater Collection at Corona
A rainwater collection system on the roof of the Corona
Maintenance Shop in Queens drains rainwater into a
40,000-gallon underground storage tank that supplies water
to a subway car wash. Approximately 80 percent of the
wash water is then collected as greywater and recycled, with
potable water used only for the final rinse.
MTA Impacts Wetlands and Vice Versa
Wetlands filter pollution found in stormwater, serve as groundwater
recharge zones, protect land from coastal
erosions and against storm surges, and provide habitat for
wildlife. These benefits, if lost, are extremely costly to recreate.
With many rights-of-way along wetlands, the MTA and its
partners have a responsibility to protect and rehabilitate wetlands.
Since wetlands buffer sea surges, the MTA also has a
vested interest in such protection. In its systemwide sustainability
planning, the MTA should include the value of wetlands,
especially in relation to climate change impacts on the coastal
environment. Dying wetlands in and around the city and
Jamaica Bay could hasten erosion, disrupt wild bird flyways,
and decrease land buffers to storm surges, which in turn
threaten the MTA’s operations and long-term sustainability.
NEAR-TERM RECOMMENDATIONS
Recommendation 1. Implement Systemwide Metering and
Submetering
The MTA should install additional water meters to develop an accurate
database covering various categories of water use, including washing
buses, washing rolling stock, parts washing, employee usage, and transformer
cooling. Metering would measure and track usage and would be
useful in developing effective conservation strategies. It would be helpful
in evaluating and monitoring effectiveness of new technologies installed.
The introduction of metering should proceed in the following phases:
• Phase One. Begin data collection on all major water demands using
metering and submetering, supported by detailed estimates based on
numbers of vehicles, pump capacities, and other data, as stated in the
Commission’s Interim Report. This would include a leak-detection program.
• Phase Two. Evaluate data to identify cost-efficient options for reducing
water use. Collect supporting information, including the proximity and quality
of alternative water sources and capital projects. Based on these analyses,
set water reduction targets.
• Phase Three. Prioritize and implement a schedule for achieving targets,
beginning with the most affordable and least disruptive steps. In addition,
the MTA should assess the value of joining the DEP automatic meter
reading initiative.
Recommendation 2. Improve the Efficiency of Vehicle Washes
Washing vehicles represents about a fifth to a third of the MTA’s water
use. MTA agencies should make greater use of stormwater, as is already
done at the Corona Maintenance Shop. The MTA should consider the
following steps for wash facilities and operations:
• Minimizing wash cycles and detergents, reducing wash frequency,
cutting the amount of rinse water, shorter wash cycles, lower pump
capacities, and using alternative water sources.
• Using advanced wash water treatments, such as: automated bus
washing, water quality sensors and automation, multimedia filters,
and chemical coagulants.
• Using nonpotable water, such as treated groundwater to wash buses.
Recommendation 3. Improve Stormwater Control and Reduce
Stormwater Runoff
Uncontrolled runoff from storms can overwhelm sewer systems, causing
Combined Sewer Overflows (CSOs) and polluting waterways. Climate
change is likely to exacerbate these problems, as discussed in the Climate
Adaptation chapter of this report. In response, the Commission recommends
that the MTA improve management of stormwater on MTA roofed
facilities, parking lots, and other non-permeable properties, targeting a
25 to 50 percent reduction in storm runoff by 2020. The Commission
recommends the following steps.