Green Roof Resource

Here’s an update on NYC green roof policy incentives as discussed previously. According to an article in Greener Buildings, bill A 11226 passed the state assembly on June 23rd. The senate had previously passed the bill on June 11th. For buildings that green at least half of the roof surface, they may receive a one-time tax credit of $4.50 per square foot (up to $100,000) of green roof.

So how does $4.50 per square foot compare with the cost of a green roof? In our study on the costs and benefits of extensive green roof systems, which included costs to install the conventional components in addition to the green components, we found that 4 inch systems were on average $22 per square foot. An intensive system would certainly cost more, and there are certainly variations in this price. Assuming this price per square foot, the incentive covers about 20% of the cost. By reducing the upfront cost with an incentive, the time required for a return on investment (ROI) is reduced considerably. Considering only energy savings and a reduced stormwater fee, typically the average green roof takes 20 years before ROI can be reached. With the additional incentive, this can reduce the time required for an average roof to 12 years. Not a bad deal.

The WEF Sustainability Conference was held this week in Washington, DC. During the conference, a multitude of available resources were recommended to learn more about green infrastructure and sustainable water management. Below is a brief list of the resources in no particular order that I found interesting. I’ve included links where appropriate. I’m still trying to track down a book that was mentioned during the opening session, Sustainable Watershed Management. Any additional information on it would be helpful.

1. The Santa Clara Valley Water District has taken significant efforts to reduce energy and water consumption through water conservation and recycling programs. Their efforts are summarized in a 2007 report entitled
From Watts to Water.

2. With climate change affecting the frequency and magnitude of storm events, JP Morgan has recently published a guide to evaluating corporate risk with a focus on water. The report, Watching Water, provides tools for assessing impacts on companies due to decreased water quantity and quality.

3. The Civil Engineering Environmental Quality Assessment and Award Scheme (CEEQUAL) is an awards scheme for acknowledging excellent environmental quality on civil projects. CEEQUAL was developed in the UK and is based upon a points system.

4. The Pacific Institute has developed two water to air models. These models provide information on the energy and air quality effects of water management projects in urban and agricultural water districts.

Last week I attended the Smart Growth speaker series at the National Building Museum. Two speakers presented on green infrastructure strategies.

The first speaker, Nancy Stoner of that Natural Resources Defense Council, presented a summary and update from the 2006 NRDC report, Rooftops to Rivers: Greening Strategies for Controlling Stormwater and Combined Sewer Overflows. I enjoyed the definition of green infrastructure that she presented:

“Green infrastructure uses soil and vegetation in urban and suburban areas to manage and treat precipitation naturally rather than collecting it in pipes.”

The majority of Stoner’s talk focused on the efforts to promote green infrastructure technologies by cities. Cities that were highlighted in the talk include Chicago, Milwaukee, Philadelphia, Portland, Seattle, New York, and Washington, DC.

Jennifer Malloy from EPA’s water quality permitting program stated that EPA supports green infrastructure (as noted in a previous post). To effectively tackle stormwater management and improve our surface waters, Malloy encouraged the idea of “rain as a resource, not a waste.” This may be apparent to gardeners, but this is a radical idea to those involved in large-scale stormwater infrastructure projects.

Green infrastructure is easy to adopt in eastern states, but under western “use it or lose it” water law, adoption is more complicated. Water that is not immediately used cannot be retained for future used. However, prior to development, a greater percentage of rainfall infiltrated the ground and a smaller percentage ran off to surface waters. Urbanization has shifted this balance sending more water downstream. Green infrastructure could serve as means of restoring this balance, but this depends upon how the laws are written in western states. Will the courts be determining the fate of green infrastructure?

This year’s Greening Rooftops for Sustainable Communities conference was held April 29th through May 2nd in Baltimore. Treehugger summarized the award winning projects here. Green Roofs for Healthy Cities has provided detailed descriptions of the winners.

The sessions were held on Thursday and Friday, and I focused my attention on the policy and research tracks. On Thursday morning, Dr. Hamid Karimi from DC’s Department of Environment presented the District’s efforts to encourage green roofs and other green infrastructure. While San Francisco has received a lot of press concerning a new ordinance that would require most new commercial and residential buildings to be LEED certified, DC’s Green Building Act of 2006 is the first major US city to require LEED for private projects. By 2009 publicly financed buildings within the District must achieve LEED Silver Certification, and by 2012 privately owned buildings must also achieve LEED Silver Certification.

In addition to establishing green building standards, the District is also tackling water quality and erosion issues. For soil erosion and sediment control, sites must retain a 0.5 inch in 24 hours storm event onsite, and those sites along the Anacostia River must retain 1.0 inch in 24 hours storm event. The Department of Environment is currently revising stormwater fees to provide financial incentives for low impact development (LID) technologies. The current fee is associated with water usage while the new system should focus on impervious surface area. This fee structure will aid incentives such as the green roof grant within the municipal separate storm sewer system (MS4) permits. Expedited permit reviews for green projects are also under consideration.

A different approach to encourage green roofs is under development in New York State. Amy Norquist of Greensulate LLC spoke of a green roof tax abatement for $6.75 per square foot of green roof. The New York State Senate bill S07745 refers to a credit of 55% of expenditures up to $5000. The New York State Assembly bill A10234 provides greater detail. These have yet to be approved but are a clear example of states beginning to direct cities toward innovative LID technologies.

The federal government is not silent on this issue either. Dov Weitman spoke about EPA’s efforts to promote green infrastructure within the framework of the National Pollutant Discharge Elimination System (NPDES) program. EPA’s green infrastructure site provides a wealth of information describing various technologies (including green roofs), research activities, policies, and case studies.

After four years, Green Roof Resource is getting a new look. I am currently updating the site for better readability and organization.

While on the topic of renewing resources, this week I came across the International Stormwater BMP Database. The resource provides data from over 300 BMP (best management practice) studies evaluating performance of these systems. While the database was initiated in 1996, I stumbled across it after reading an article in the May issue of Stormwater. “Can Stormwater BMPs reduce bacteria?” reports that bacteria counts in BMP outlets vary widely, but in general retention ponds and media filters have the potential to reduce bacteria. There is concern that vegetative swales and other similar BMPs may attract wildlife and domestic animals increasing the concentration of fecal coliform in stormwater runoff from these systems. The concentration often exceeds the standard for recreational primary contact in waterways.

It was exciting to see that green roof runoff was included in the evaluation. However, with data being obtained from only one site (Hamilton Ecoroof in Portland, Oregon), analysis of the data was limited.

It would be interesting to evaluated BMPs in combination. For example, if retention ponds are effective at reducing fecal coliform concentration, can bioswales or green roofs reduce the size of a downstream retention pond to enable use of the BMP in areas where land is limited? Or is the apparent reduction simply an artifact of where these systems are typically used? For example, are retention ponds able to reduce fecal coliform concentration in the effluent simply because there is less in the influent? Perhaps in areas where fecal coliform is a greater problem, more conventional methods are appropriate. While fecal coliform concentration is a health concern and is contribute to beach and water closings access after rain events, one must not forget about the volume of storm events. BMPs are effective at reducing total volume of runoff entering waterways, and one should also consider the total load of contaminants exiting these systems in addition to the concentration of contaminants.