Green Area Ratio Q&A Reply

ZoningDC sat down with OP Sustainability Planner Laine Cidlowski to discuss the District’s proposed ‘Green Area Ratio’ (GAR).

1. What is the District’s proposed GAR and how does it work?

The GAR is a way for the city to ensure environmental performance through the open spaces we are requiring through zoning. The GAR is an environmental site-sustainability metric. In other words, we figure out the environmental benefit of a piece of property by figuring out the landscape elements that contribute to air quality, water quality, and heat island effect. The landscape elements can be things like trees, rain gardens, or vegetated roofs, and each has a weighted number of points. We multiply these landscape elements by their multiplier and add them up. We divide that total by the size of the piece of property – that’s the GAR.

2. Why does OP believe the GAR is a good idea?

The GAR will help the District address many different environmental issues through a regulation that’s flexible and provides many options for property owners and developers.

3. How is the GAR different than LEED?

LEED is a sustainable system for buildings and choosing the site of a building or buildings. GAR is primarily for your site, but it can also include “landscape” elements which can be part of the exterior of your building, such as a green roof or solar panels.

Seattle has implemented its own GAR.


4. Who will be affected by the GAR? Will it apply to single-family homes?

GAR will not apply to single-family homes. GAR will apply for all buildings that need a Certificate of Occupancy. That is, multi-family residential buildings (over 2 units) and commercial properties. The majority of housing stock in the District (approximately 60%) is made up of structures with two units or less and GAR would not apply. Instead, those property owners would have simpler requirements relating to the amount of pervious surfaces on their property.


5. Do the regulations include standards to determine whether landscaping elements aid in stormwater retention or treatment?

No, but we expect that if you are meeting the GAR on site, you will be meeting your stormwater requirements, which are required for larger properties or land disturbances only. We have designed the GAR review process so that your process will be in sync with stormwater requirements.

6. Will the environmental benefits of the GAR have an impact District-wide or even regionally?

Yes, we hope to get some research on the initial implementation that will help us to better understand the output of the GAR and this will better help the District meet the EPA’s stormwater requirements.

7. Once they are built, will the environmental performance of these features be monitored?

We will have the projects inspected on the same cycle as projects which must meet the stormwater requirements (approximately every three years), but we hope to have some sample sites monitored more often. The environmental benefits of projects implemented through GAR will be built into their designs and subject to an initial review process– the idea is to make the process as easy as possible.

8. How would you respond to those who say that the GAR could lead to bigger setbacks and useless green space in front of buildings (meaning less residential units or office space) thereby reducing street vitality?

The GAR will have no effect on the density you are allowed to have. And it’s important to point out that a property may be able to meet its GAR requirement—even with a building covering 100% of the lot—if it simply installed a green roof. What we are hoping is that in the open space around developments that there will be less concrete and more green space. There is nothing in the current regulations that would prevent someone from paving over their entire property. Under increasing EPA regulations, the District has to reduce its impervious surface and treat more stormwater or else be subject to huge fines. We need to do something to ensure that private property owners as well as the government are changing the way land is developed to meet these new requirements.

9. Where else has GAR been tried?

GAR has been tried in Seattle and Berlin. Berlin implemented its program in 2002 and Seattle implemented its program in 2006. Seattle’s program started with new development in commercial and neighborhood commercial zones outside of downtown and the city expanded the program to cover multi-family residential and high-density residential areas. These efforts have been successful; however, Seattle has made some adjustments to the initial text based on feedback and we expect to do the same as it is needed.

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