Solving Urbanization Challenges by Design



Columbia University Green Roof Consortium

The Columbia University Green Roof Consortium is a group of researchers and research students who are interested in understanding the role that green roofs might play in urban sustainability.


Research Findings

A recent study by this multidisciplinary research team recorded heat and rainfall data at a modular green roof and modeled them mathematically. The findings included:

  • The roof retained 30 percent of incident rain and snowfall annually
  • The roof retained about 10 US gallons per square foot annually
  • The retention amounts are 22 times greater than assumptions made by New York City planners
  • Based on these figures, estimated costs are $US 0.15 per gallon retained annually
  • Based on different assumptions about maintenance costs, estimated costs are even lower: $US0.02 per gallon retained annually
  • The modular system did not perform as well as a continuous green roof

To download a copy of a document titled Stormwater Retention for a Modular Green Roof Using Energy Balance Data, click on this link:


To Learn More:

To read about the research work underway at Columbia University, click on Solving Urbanization Challenges by Design – The Science of Green Roofs. This links to an interview with Patricia J. Culligan, a professor of civil engineering and engineering mechanics at Columbia University and the Vice Dean of Academic Affairs for Columbia Engineering.

In part one of this interview Culligan discussed her her work with the Columbia University Green Roof Consortium to quantify the ecological benefits of green roofs.

In part two she talks about the challenge of quantifying the economic benefits of green roofs, the potential for rooftop agriculture, and what it means to “solve urbanization challenges by design.”


Posted May 2011