A Quest for Green Roofs in the District of Columbia

On my recent trip to Washington, D.C. I went on a quest looking for green roofs. Not metal roofs, painted green, as one person I asked directions from thought, but those sporting live plants that provide a host of environmental benefits in urban areas. The District is a strong supporter of sustainable development and has an active stormwater control program called "RiverSmart". The RiverSmart program provides financial assistance to property owners to install green infrastructure projects which will help capture rainwater on-site so that it doesn't run-off their property, carrying with it pollutants, such as fertilizer and sediment, into storm drains and surface waters. One of their projects for which they are a pioneer is RiverSmart Rooftops which supports the installation of green roofs by providing rebates of $10 -$15 per square foot. In addition to capturing rainwater, green roofs help cool buildings in the summer, as well as the surrounding air, combating the heat island effect in cities. And, green roofs, if planted with larger shrubs and trees can help capture air pollution.

Before my trip, I printed a five page list of the green roofs that have already been installed under the RiverSmart program.  Unfortunately, I quickly learned that gaining access to roof-tops is a near impossible task, especially without prior planning. If I had contacted property owners before my trip, I probably could have gained permission to have supervised access to at least a couple roof-top gardens. Never-the-less It was a fun and different way to explore the city, even if I did have to be content seeing most of the plantings from a distance.

Even if you are not consciously looking, it is not hard to spot green roofs from the street.

From public office buildings, to private apartment complexes, trees are visible by just looking up.

Although it was interesting seeing the plants from the street, I was hoping to get a closeup view of at least one rooftop. After several unsuccessful inquiries at private buildings, I went up to Capital Hill to the U.S. Supreme Court building, since according to my list they had built a green room as part of a 2008 modernization effort. I could not confirm this to be the case, but the helpful employee at the information desk did direct me to the Senate office buildings which were just a few blocks away. I started at the Dirksen Senate Office Building, 130 Constitution Avenue NE with no luck, so decided to walk to the connecting Hart Senate Office Building where my state, Senator Jeanne Shaheen's office is located. I still  could not get access to the actual roof, her office did direct me inside to the floor where a window overlooked the rooftop.

My first view out the window was not of the outdoors, but of indoor plants which offer the same benefits of purifying the air and providing inhabitants with a general sense of well-being.

Finally, I got my first close-up view of a green roof atop the Dirksen Senate Office Building. Since it was early spring it wasn't exactly "green", except for some grass sprouting along the edge.

A green roof installed as part of the RiverSmart program

If you ever go to the Library of Congress Packard Campus of National Audio Visual Conservation Center, you will see the huge investment they have made in making it a truly sustainable campus. On Capitol Hill, as well, the Library of Congress buildings along Independence Avenue are covered with ground cover and trees.

Getting to see the tress up close on top of the Library of Congress Building was not possible, but there is plenty of greenscaping visible around the building.

Elevated Gardens Along the Library of Congress Madison Building

At the House Office Buildings next door, there were several vegetative planting areas on the rooftops that were visible from inside the stairwell.

I was impressed with how the property owners of D.C. have embraced the concept of vegetative roofs; and, as I concluded my tour, I also took notice of the landscaping plants on the ground where everyone can enjoy them.

May 28, 2015 Update: Green Roofs for Health Cities ranked Washington, D.C. Number 1 as the Greenest City in North America. Toronto, which requires all new construction of a certain size and over six stories tall to have at least 20 per cent of the roof vegetated.