Despite all the hoopla about green roofs, many of them are not really green. Vegetated is a more accurate description, and summer may be the best time to see them in their glory. That was true when the Board of Supervisors held a ribbon cutting to celebrate Fairfax County’s latest green initiative at the Herrity Building parking structure last Monday morning.

The shared parking structure on the grounds of the Fairfax County Government complex has several concrete decks, and the top one is perfect for a vegetated roof. Several years ago, the Board of Supervisors asked the Department of Public Works and Environmental Services to prepare a retrofit of some parking spaces as part of the Cool Counties initiative sparked by Fairfax County and other large urban counties. The new green roof will be monitored for how much stormwater and pollution it absorbs, an exercise that will be compared to an unplanted area on the opposite side of the garage.

Vegetated roofs use a combination of soil, gravel, and other planting mediums, and have drainage built into them to allow water to be absorbed slowly instead of running off into local streams. The Herrity Building roof features both extensive and intensive roofs. The extensive part uses low-growing, drought tolerant vegetation, such as varieties of sedum, planted in “engineered” soil. The wide shallow beds are bordered by crushed rock walkways that allow visitors to get a closer look at the plantings. Farther back, near the edge of the parking structure, an intensive portion contains deep soil, almost like a very large and deep window box, which allows for a wider choice of plants, including trees. On Monday, golden coneflowers in bloom provided a lovely contrast to the low-growing sedums.

In his remarks at the brief ceremony, Board Chairman Gerry Connolly said the demonstration project supports the Board’s green building policy, adopted earlier this year, that requires county buildings be constructed to meet minimum green building standards and, if possible, exceed them. Green building projects in Fairfax County include a vegetated shed roof and pervious paver parking lot at Fire Station 30, shared with the Providence District Supervisor’s office; Fire Station 40 at Fairfax Center; Fire Station 41 at Crosspointe; and the new pervious paver parking lot and rain garden at the Hidden Oaks Nature Center in Mason District.

Just in case you haven’t heard – there is a Presidential election this fall! Both major political parties are hard at work registering new voters in Virginia, and both Democrats and Republicans are reminding voters that they can vote absentee prior to the November 4 General Election date. If you are eligible to vote and haven’t registered yet (deadline to register is October 7), you may find more information at the Virginia State Board of Elections Web site, which also has instructions about voting absentee: www.sbe.virginia.gov/cms. A lot of young voters don’t live at home, so please remind your college students to register and apply for an absentee ballot. In-person absentee voting at satellite locations will begin in mid-October in Fairfax County, and I will provide that information in a future column.