NYC Green Infrastructure Plan

Posted on Sun, 2012-07-08 17:50 by matt

Traditional  approaches  to reduce CSOs further  would include the  construction of additional, large  infrastructure, but  the remaining opportunities for such construction are very expensive, and  do not provide the sustainability  benefits  that  New  Yorkers rightly  expect from  multi-billion dollar  investments  of public funds.

This Green  Infrastructure Plan presents an alternative approach to improving water quality that integrates ―green infrastructure,‖ such as swales and  green roofs, with investments to optimize the existing system and  to build targeted, smaller-scale ―grey‖ or traditional infrastructure. This is a multi-pronged, modular, and  adaptive approach to a complicated problem that  will provide widespread, immediate benefits  at  a  lower  cost.  The green  infrastructure component  of  this strategy builds upon  and  reinforces  the strong public and  government support that  will be nec- essary to make  additional water quality investments.  A critical goal  of the  green  infrastructure component is to manage runoff from 10% of the impervious surfaces in combined sewer water- sheds through detention and  infiltration source controls.

New York City’s ―Green Strategy‖ is nimble enough  to incorporate new technologies and  approaches as they  emerge during  the implementation of our plan.  DEP will preserve  its ability  to pursue  larger  grey  infrastructure if necessary  and  appropriate in the  event that  the  Green Strategy  cannot achieve water quality  objectives  in a  particular  drainage area.  Promoting green  infrastructure has  been endorsed by  the  U.S. Environmental Protection  Agency (EPA) and  the New York State Department of Environmental Conservation (DEC). Under Administrator Lisa Jackson, EPA has testified that green infrastructure is an ―effective response to a variety of environmental challenges that  is cost-effective, sustainable, and  provides  multiple desirable environmental outcomes.‖ (Testimony before the U.S. House of Representatives, Committee on Transportation and  Infrastructure, Subcommittee on Water  Resources and  Environment, March 19, 2009)

The  goal  of 10% capture  over  20 years could be met through a combination of:

  • Three percent (3%) impervious area  capture by street trees, swales, and  sidewalks that are rebuilt or retrofitted with additional controls;
  • Three percent (3%) impervious area  capture by performance standards on new and   expanded developments that  would include bio-infiltration, blue and green roofs, sub-surface detention / infiltration, or other source controls;
  • Three percent (3%) impervious area  capture by existing schools, residences,  and  other development; and
  • One percent (1%) impervious area  capture by additional planted areas in open spaces and  waterfront areas.

To accelerate the implementation of green  infrastructure, DEP is building more than  20 demonstration projects in collaboration with  other  city  agencies and  local  authorities. These demonstration projects are  testing  techniques that  are appropriate for a variety  of land  uses:

  • Green  roofs for rooftop stormwater detention and  retention;
  • Porous pavement for parking lots;
  • Tree pits, street side swales, and  porous pavement for roadways;
  • Green streets, medians, and  curbside extensions for roads;
  • Constructed wetlands and  swales for parks;
  • A variety  of these techniques for high density multi-family housing; and
  • Rain barrels for low density single family housing.