A NEW MEANING TO THE COLLEGE “GREEN”

18 12 2009

Green Roof Dashboard
from Davis Center at University of Vermont

With a son who is a sophomore in college and a daughter as a high school senior, I have managed to spend a lot of time visiting college campuses over the past few years. One of the things that I have paid particular attention to (and seen an huge increase in during the past two years) is the focus on sustainability. My strong hunch is that schools are incorporating sustainable technologies because this generation of smart, college age youth demand it.

Many college campuses now sport LEED certification on at least one building – my son’s dorm at the University of Richmond (Lakeview Hall) is LEED registered and undergoing certification. It is one of nine buildings at the University which is either certified, or in process of being certified as LEED with the USGBC. Locally, Vanderbilt University completed the LEED certified The Commons at Vanderbilt residential housing complex in 2008. As I have traversed the country and seen what must be dozens of (mostly) smaller liberal arts colleges, I have seen organic gardens and solar panels at Whitman College, windmills and biomass generators at Middlebury, local and organic foods at Skidmore, a unique “homestead” intentional environmental community at Denison, beautiful rain gardens at Emory and the list goes on.

I also found a interesting resource online called the College Sustainability Report Card for 2010 (www.greenreportcard.org), This report card basically looks at environmental sustainability at over 325 colleges and universities in the United States and Canada based on 48 indicators used to evaluate performance within four categories.

One of those categories is “green building”. It was heartening to see that 44% of the schools have had at least one LEED-certified green building or are in process of constructing one and a whopping three-quarters of all of the schools have adopted green building policies that specify minimum performance levels such as LEED certification for new construction.

I was particularly interested in taking a closer look at some of the successes that I have witnessed at several of the schools that I have visited especially as they relate to green infrastructure. I found some additional information on Emory, Allegheny, Middlebury, University of Vermont and Macalester.

WATER CONSERVATION

As a part of Emory University in Atlanta’s overall commitment to sustainability (with over 1 million square feet in LEED certified buildings), Emory has incorporated many innovative water-conservation technologies.. Particularly impressive to me was their implementation of rainwater harvesting and condensate recovery, especially in light of the fact that Atlanta suffered an historic drought event in the summer of 2007. On Emory’s whole campus they have to date included 6 cisterns with a collective size of over 350,000 gallons for both toilet flushing and for irrigation as well as a condensate recovery technology for over 4 million gallons of water per year.

In their new freshman residence complex including Ignatius Few Hall and Lettie Pate Whitehead Evans Hall, rainwater and condensate collection is diverted to an 89,000 gallon reservoir underground which can provide adequate volume to provide 2170 gallons per day needed to flush all toilets int eh buildings. The rainwater is collected form the roof, then filtered and slowed through a bioswale system outsde of the building and then into the below grade cistern. The condensate harvest provides a reliable source of water to supplement rainfall during those months from May through September. It is estimated that the condensate harvests is adding 300,000 gallons per year to the system.

At the nearby Whitehead Biomedical Research Facility Building, completed in 2001, the engineers devised a system of piping condensate back into nearby cooling towers to use as make-up water. This system conserves water AND diverts 2.5 million (that’s 2,500,000) gallons a year from the sanitary sewer system.

Video About Emory University’s Sustainability Efforts

GREEN ROOFS

It seems to me that many, many schools are incorporating green roofs as that technology provides one of the most visible elements to show-off sustainable design. In every school we visited, if there WAS a green roof, it was highlighted on the student led campus tours. The green roof were touted for their well-documented benefits such as longer roof life, reduced cost of heating and cooling, stormwater runoff reduction and habitat.

Allegheny College in Meadville, Pennsylvania impressed me with the well designed green roof on the Vukovich Center for Communication Arts. It is located within the topography of the campus site allowing for a fully accessible roof (entering the building at the green roof on the high side and entering on a lower level to the main campus commons or quad –type area. The roof includes extensive and semi-intensive depths and features lawn space as well as sedums and native grasses with an interesting incorporation of stones and cedar decking through the rooftop.

University of Vermont, just on the edge of downtown Burlington, Vermont, recently completed the 186,000 s.f. Dudley H. Davis Center. The Center features a 19,000 s.f. green roof.

Middlebury College, also in Vermont, provided a sloped green roof above the Atwater Dining Hall. I was interested in seeing their notation that in addition to the traditional green roof benefits that I have seen listed in may locations, Middlebury includes improved acoustical insulation, noting that green roof systems can reduce airborne sound levels by 40 to 50 decibels.

Macalester College in St. Paul, Minnesota impressed me, not in size but in determination. The two green roofs on campus were the result of student designs and even some student labor! The first green roof at Macalester was a 300 s.f. tray system installed above a walkway between tow residence halls and the newer 1350 s.f. green roof on Kagin Commons. I happened to be on campus the day the Kagin Commons green roof was unveiled.

I believe the influence of these campuses and so many others will influence the bright minds of our next generation of decision makers and leaders.





New Downtown High-rise Includes Green Roof

30 11 2009

The Pinnacle at Symphony Place, a 29-story office building in downtown Nashville, opened this month. The building includes 520,000sf of Class A office space. It is home to law offices of Bass Berry and Simms and the headquarters of Pinnacle Financial Partners. The building designed by the award winning architectural firm Pickard Chilton with Nashville architects EOA Architects is anticipated to receive LEED-Silver certification from the United States Green Building Council (USGBC). With the inclusion of a 28,000sf rooftop garden, the building contributes significantly to Nashville’s ever growing green infrastructure

The green roof, designed by our office, is located on the 7th floor above the parking garage and includes a series of spaces that can be enjoyed by the building’s tenants. The area is comprised of 9,400sf of pedestal pavers and 19,000sf of vegetated areas. One hundred percent (100%) of the pavers were selected to exceed the minimum solar reflectance standards established by the LEED rating system. The striping pattern continues the prominent vertical fins on the facade of the building into the rooftop garden area. The planting areas are a combination of extensive green roof (planting media depths ranging between 5-9”) and semi-intensive areas (planting media depths ranging between 18”-30”). The semi-intensive areas were planted to reflect a more traditional landscape around each of the gathering areas and provide areas for trees to shade and scale the spaces. In an effort to establish a more pedestrian scaled environment and additional interest a series of 12ft pyramidal trellis structures were incorporated in the extensive green roof areas.

It is estimated that the green roof can retain nearly 67% of the annual rainfall falling directly on it. In addition, it reduces the peak flows, is significantly cooler than neighboring conventional roofs, reduces thermal heat gains in the water that enters the stormwater system, and provides a beautiful space to look upon and enjoy.

We are honored to have been a part of such an exciting project and look forward to watching it grow. We have been pleasantly surprised by the significant growth the plant material has shown in a short time period. As it matures, we will keep you up to date on its progress.

-Brian Phelps





A Different Kind of Green Roof

4 11 2009

Research has begun on a light weight alternative to extensive green roofs (the least intense form of a green roof) for when structural loads or costs might otherwise deter a client from choosing to pursue a green roof. It is being referred to as a ‘green cloak’ and uses fast growing vine species that attach to a trellis suspended above the roof. Laura Schumann, a graduate student at the University of Maryland completed her thesis on the cost benefits for temperature and stormwater using green cloaks. More complete information on temperature and stormwater reduction can be found on the University’s website.

While green cloaks will likely never provide near the benefits of an actual green roof system, a major potential is that they are probably a less expensive option when installing a green roof is just too cost prohibitive and a client is still looking for a way to save on energy costs. In addition to reducing cooling costs and slowing the runoff of stormwater from roofs, one of the most intriguing facets may be the potential for using vine and trellis systems on sloped roofs where it is currently challenging to implement traditional green roof systems. Another aspect is that vines have the potential to provide cover for vertical surfaces and may help provide even greater temperature benefits when combined to cloak walls as well.

The vine species researched in the study included 5 different species: cross vine (Bignonia capreolata), kudzu (Pueraria lobata), Japanese Honeysuckle (Lonicera japonica), porcelain berry (Ampelopsis brevipedunculata), and Virginia creeper (Parthenocissus quinquefolia).

Virginia Creeper

Testing Virgina Creeper's effects on Building Temperature (Photo from Univerisity of Maryland's website)

One drawback may be that green cloaks might not be as aesthetically pleasing to the masses as green roofs and could be a hard sell for more refined urban or retail areas. And it may also be difficult to provide full coverage for large roofs, however even partial coverage could provide huge cost savings in cooling costs for big box retailers or manufacturer’s with large warehouses where load bearing capacities for roofs are low and aesthetics are not as much of a concern. Either way, this is another potential option available for designers to help reduce energy costs, the urban heat island, and reduce stormwater runoff.

– Sara Putney

GreenCloakTilley.ppt

Inspiration (photo from 'Green Cloak' Presentation, David R. Tilley, University of Maryland)





Green Roofs Address D.C.’s Environmental Problems

30 10 2009

asla green roofPhoto Source: ASLA

It has been three years since the American Society of Landscape Architects (ASLA) finished the 3,000sf green roof on top of the their headquarters building in Washington D.C. The green roof is unusual in that it is sloped to cover the mechanical units on the roof. An informative video (link to video) was posted on Youtube this month highlighting the stormwater benefits of the ASLA roof. Nancy Somerville, ASLA’s CEO was interviewed during the video and she stressed the important role green roofs could play in helping address Washington D.C.’s and the nation’s difficult stormwater issues (i.e. water pollution, Combined Sewer Overflows). An EPA report estimated 850 billion gallons of untreated sewage and stormwater are discharged nationally each year as combined sewer overflows. (EPA Fact Sheet [pdf]) As Ms. Somerville points out, green roofs can filter the stormwater falling on the roof as well as act as a sponge and significantly reduce the amount of stormwater coming off of the roof. A green roof with 4″ deep planting media has been shown to retain 63% of the rain fall hitting the roof.

During the first year, ASLA conducted a study (link to ASLA green roof website) to quantify the specific benefits of the their green roof. The data showed that 74% of the water was retained on the roof. Interestingly, the water quality of the stormwater discharge leaving the roof included an increase in pH and temperature as compared to the rain fall. In addition, the test results showed a significant increase over the concentration originally present in rain water for Chemical Oxygen Demand (COD), phosphate, total phosphorus, total suspended solids, and total dissolved solids. According to the report most of these contaminants were within the allowed freshwater chronic concentration values established by the E.P.A. and none of the concentrations were above the acute level. Unfortunately, the study did not compare the green roof with a conventional roof. The report concluded that “Green roofs have significant potential for reducing stormwater carried pollutants in major metropolitan areas such as Washington DC. However, more comprehensive and extensive monitoring studies are needed to evaluate specific performance measures of specific designs and develop accurate predictive tools.” The following are a few specific findings highlighted in their press release (.doc):

  • The roof typically retained 100 percent of a one-inch rainfall.
  • The heaviest rainfall during the monitored period was March 16, 2007. A total of 2.48 inches of rain fell during the 24-hour period with the roof retaining 51 percent, the equivalent of 1.3 inches of rain.
  • The green roof did not add any nitrogen to the runoff. Because of the amount of water retained, the roof provided a significant reduction in the amount of nitrogen introduced back into the watershed.
  • Typical of “young” green roofs, the analysis showed higher amounts of some other nutrients such as phosphorus, as well as heavy metals in the runoff—all below EPA standards and below levels expected from street runoff. Based on other green roof research, nutrient levels are expected to decrease in a few years. The heavy metals may be coming from the roof materials or from settled particulate matter/pollutants.
  • It is important to note that this study did not look at runoff from a conventional roof compared to the green roof runoff—and the results would be expected to look different. Water quality testing will be repeated in two years to see how the results change over time with a goal of comparing the green roof runoff to conventional roof runoff.
  • The green roof has been as much as 32 degrees cooler than conventional black roofs on neighboring buildings.
  • Engineering analysis showed that the green roof created a 10 percent reduction in building energy use during winter months and negligible difference in the summer.

On a city wide level, the Casey Tree, a non-profit dedicated to restoring, enhancing and protecting the tree canopy of the Nation’s Capital, conducted a study (link to study) of the Washington D.C. area that examined the impact of green roofs and tree plantings. They concluded that if 55 million square feet of green roofs were installed throughout the Washington D.C. area, they would reduce the reduce CSO discharges by 435 million gallons or 19% each year.

These studies illustrate the effectiveness of including green infrastructure within the overall strategy for cleaning up our nation’s stormwater.

-Brian Phelps





What SHOULD be green about our city’s infrastructure?

19 10 2009

green_infrastructure

Green. These days that one word has many different meanings. Growing up, I could count on “green” being one of the eight colors in a Crayola package, but today, this one word has many more connotations. Being landscape architects, we plan to use this blog as a way to explore “green” in terms of site sustainability issues, with a focus on green infrastructure. So maybe we start with the first question: What SHOULD be green about our city’s infrastructure?

When we think about stormwater infrastructure, it is generally conceived of as the complex system that accepts, stores, manages and treats our stormwater. In the conventional designs of the past several decades, this has been done through drains, pipes, curb and gutter and a whole host of devices to hold or detain the water from our bigger storms. With green infrastructure, we look at the potentials of natural systems to deal with those same issues: more interception of stormwater allowing it to evapo-transpire, infiltrate and be held and used for others purposes (like irrigation or flushing water for toilets). This reduces the load on our aging storm pipe system, allowing it to function longer AND it often allows a more cost-efficient solution for the life of the project.

Specifically here at Green Infrastructure Digest we’ll discuss green infrastructure as it relates to four primary areas:

  • buildings and structures/ green roofs and green walls
  • hardscape / pervious pavements and overflow inlets
  • landscape / bio-swales, raingardens, green streets
  • water capture and reuse / rainwater harvesting, greywater harvesting, passive irrigation
  • related site sustainability issues

Over the past 23 years at our firm, Hawkins Partners, Inc. landscape architects, we have had the opportunity to put this talk into practice having now designed over 500,000 s.f. of green roof, being involved in the first three LEED projects in the State of Tennessee (and many more since then) and incorporating many of these sustainable practices effectively in a number of different projects. We find that our clients like the idea of getting back to natural systems and putting dollars into aesthetically pleasing solutions that also deliver an environmentally sound and cost-conscious solution.