Interview with Portland BES Part 1 of 3

3 02 2010

Portland Building (Location of Portland BES Offices)
Source: City of Portland, Environmental Services ©2009

The following is the first part of an email interview I recently conducted with Emily Hauth, project manager with Portland Bureau of Environmental Services (BES)’s Sustainable Stormwater Management Division. Their agency has been a leader in sustainable stormwater implmentation over the last twenty years.

Green Infrastructure Digest (GrID): The City of Portland has been and continues to be a leader in implementing green infrastructure facilities. Please tell our readers a little bit about the work the Bureau of Environmental Services (BES) is doing in regard to increasing the use of green infrastructure. What new innovations should we expect to see out of BES in the coming years?

Ms. Emily Hauth: Our sustainable stormwater management solutions have evolved from a single purpose regulatory driven approach to one that achieves multiple objectives. We are designing our urban landscapes and street systems with an eye toward community enhancement, cooling of the air and water, increased wildlife habitat and greenspace, safe bike and pedestrian linkages, greenway connections to services and amenities, and of course capturing and treating stormwater at the source on the surface. In this way we are achieving watershed health goals and meeting regulatory compliance while informing a new approach to urban development.

We are incorporating green infrastructure approaches into our policy development and planning processes. We have a number of policy initiatives that recognize green infrastructure solutions as a smart way to plan for watershed health and the city’s future and direct city bureaus and agencies to cooperatively plan and implement green infrastructure elements as part of all work programs. Our bureau works collaboratively with other City bureaus and agencies such as our Bureau Of Transportation and the Portland Development Commission on projects that promote environmental concepts while addressing auto, pedestrian, and bicycle safety. We are also fully integrating our watershed health and stormwater/sanitary collection goals into our Systems planning process. Portland’s Grey to Green initiative, established in 2007, sets a 5-year goal to increase green infrastructure elements throughout Portland including 900 Green Streets, 43 acres of Ecoroofs, and over 50,000 new trees.

In one particular area of the city where pipes are failing or undersized, we are incorporating green street facilities into the solutions plan. This area is referred to as Tabor to the River. In this area alone, we will be constructing 500 green streets. We’re also working closely with targeted private property owners to help them manage stormwater on their sites and play a role in the solution. All future work to address similar issues will follow this model of combining grey and green infrastructure solutions.

We don’t feel we have all the answers so we continue to ask ourselves, is it working? We continue to monitor our facilities, modify designs, research components such as plants and soils, to refine our knowledge base and maximize facility function and performance. We’re always looking for efficiencies in design and construction so we’re evaluating use of modular or prefabricated components for sustainable stormwater solutions. Other innovations we’re exploring include using a curbless green street design, new design options that manage both public and private runoff, and green walls that manage stormwater. We’re also developing a volunteer green street maintenance program that engages the community while helping the city meet its maintenance needs.

Planter at Mississippi Commons
Source: City of Portland, Environmental Services ©2009

Part 2-On Friday

-Brian Phelps

Toronto’s Green Roof Requirements Take Effect Monday

29 01 2010

Downtown Toronto
Photo Credit:

On Monday, Toronto’s ambitious
green roof standards will go into effect. Any roof of a building over 2,000m2 will be required to include a green roof for a portion of the building. High-rise tower roofs that are 750m2 or less are exempt. The following is the breakdown of the required percentages of the roof area based on its size:

  • 2,000m2(21,528sf*) to 4,999m2 (53,809sf*) = 20%
  • 5,000m2 (53,810sf*) to 9,999m2 (107,629sf*) = 30%
  • 10,000m2 (107,630sf*) to 14,999m2 (161,449sf*) = 40%
  • 15,000m2 (161,450sf*) to 19,999m2(215,269sf*) = 50%
  • 20,000m2(215,270sf*) or greater = 60%

*square footage calculations are approximate

These standards will initially cover all building types with the exception of industrial. Industrial building requirements will take effect in 2011. To put these standards into context, the 20% requirements would include a typical modern office building to a medium size neighborhood grocery to a smaller big box store. Most stand alone restaurants and smaller residential projects would likely not meet the threshold to require a green roof. The other requirement levels would cover larger big box and larger grocery stores, significant retail centers, and industrial/warehouse facilities.

Interestingly, the available roof area that is used to calculate the requirements excludes areas designated for renewable energy, private terraces, and residential amenity areas (to a maximum of 2m2/21sf per unit).

The City’s eco-roof incentives program that provides $50/per m2 up to a maximum of $100,000 is still in place. According to their website, applications are being accepted starting March 1st. The deadline is April 1st. Award projects will be decided on April 16th.

This initiative is being launched in conjunction with the City’s new Green Standards Program. It reminds me of the United States Green Building Council’s (USGBC) LEED checklist. The program includes three categories, each having their own but similar requirements. The categories include low-rise non-residential, low-rise residential, and mid-high Rise (any use).

Additionally, the new standards do encourage green infrastructure requirements such as:

  • Retain stormwater on-site to the same level of annual volume of overland runoff allowable under pre-development conditions and retain at least the first 5 mm from each rainfall through rainwater reuse, onsite infiltration, and evapo-transpiration or ensure that the maximum allowable annual runoff volume from the development site is no more than 50% of the total average annual rainfall depth
  • Remove 80% of total suspended solids (TSS) on an annual loading basis from all runoff leaving the site based on the post- development level of imperviousness. Control amount of E. Coli directly entering Lake Ontario and waterfront areas as identified in the Wet Weather Flow Management Guidelines

Due to the legal ramifications of a continually evolving third-party system like LEED, we will likely see more city -specific green building programs being developed over the coming decade as cities seek to separate themselves and focus on the particular aspects of sustainable design that have the largest impact in their community.

You can find all of the standards on the City’s website here.

-Brian Phelps

A Vision: Green Roofs in Birmingham

20 01 2010

Downtown Birmingham, AL with Green Roofs
Rendering by: Hawkins Partners, Aerial from Live Local Maps (Now Bing)

A few years ago, I put this illustration together for a green roof presentation to the Birmingham branch of the Alabama Chapter of the USGBC. Images like this provide a compelling illustration of what the city could look like if every building added a green roof.

-Brian Phelps

Video Tour of ASLA’s Green Roof

4 01 2010

Back in October 2009 in our post “Green Roofs Address D.C.’s Environmental Problems”, we covered the research the American Society of Landscape Architects was doing with the green roof on its National headquarters and the many benefits it provides. I recently came across this well produced video tour of ASLA’s green roof (see below). It does a wonderful job of showing off the space and the diverse habitat that has been created. I particularly love the areas that use the steel grating to span some of the green roof areas. Enjoy.

Cooling Our Cities: An Interview with Dr. David Sailor

23 12 2009

I had the pleasure of conducting an email interview with Dr. David Sailor, the director of the Green Building Research Laboratory (GBRL) at Portland State University (link to resume). He is a leading researcher in the effects of green roofs and energy use in buildings and the impact green infrastructure can have on cooling our cities. He and his colleagues have developed tools to help quantify these impacts.

Green Infrastructure Digest (GrID): I understand that this year you became the first Director of the Green Building Research Laboratory (GBRL) at Portland State University. What is the focus of the research you are conducting at GBRL? Why and how was GBRL started?

Dr. David Sailor: The Green Building Research Laboratory was essentially an outgrowth of the funded research agendas of myself and my GBRL colleagues. This group of Portland State University faculty included Graig Spolek in Mechanical and Materials Engineering, Loren Lutzenhiser r in Urban Studies, and Sergio Palleroni in Architecture. Over the years we had developed a number of collaborative projects and decided it was time to build upon this collaboration by creating a physical laboratory where we, our students, and our industry partners could work together on fundamental and applied research to benefit the green building industry.

We pitched the idea of a collaborative shared-user facility to Oregon BEST and to the PSU Center for Sustainable Processes and Practices, both of whom agreed to provide the initial funding for the lab. As a result, while the lab was initiated by four faculty members at Portland State, it really serves as an Oregon University System shared resource.

There really is a wide range of research activities going on in the lab. This includes several monitoring projects with local builders, property owners, and school districts with a focus on understanding the thermal and moisture performance of building envelopes as well as the indoor environmental quality of these buildings. We also continue to make advances in the monitoring and modeling of green roof performance. Personally I have been involved in a number of monitoring projects and in creating an energy modeling tool for evaluating the energy performance of green roof design decisions. My colleague Graig Spolek has been using some of the GBRL water quality testing equipment to better understand the chemical composition of green roof runoff. We are also using GBRL facilities to understand the interactions between buildings and the urban atmospheric environment. This involves both modeling and field measurements.

GrID: A lot of your research has been focused on green roofs and heat island mitigation through the use of green infrastructure. How significant of a role does green infrastructure have in addressing thermal heat gain within our built environment? It appears through the tools you have developed for the MIST program that you have been able to quantify these impacts? Can you explain to our readers, what the MIST program entails?

Dr. Sailor: Yes, my research career actually started with a focus on urban heat island mitigation through use of urban vegetation and highly reflective (high albedo) urban surfaces. The US EPA funded some of my early modeling efforts in an attempt to provide a quantitative assessment of how much potential there is for cities to cool their summertime air temperatures through city-wide modification of urban surface characteristics (vegetation and albedo). We used regional scale atmospheric models of about 20 cities across the US to create information on the potential impacts of such mitigation on summertime urban air temperatures, peak ozone concentrations, and energy consumption. The result of that was a fairly user-friendly urban heat island screening tool – the Mitigation Impact Screening Tool – or MIST. The tool uses fairly simple interpolation and extrapolation of our modeled results so that policy makers in any US city can easily estimate the order of magnitude of the impact that any particular mitigation strategy might have in their city. I like to emphasize the “S” in MIST – this is a Screening tool. Ultimately, any policy decisions that involve significant investment of public funds to mitigate the urban heat island ought to be based on a more thorough, city-specific analysis – which of course can start by running MIST.

Thermal Imaging Photo of Portland Buildings (Summer 2009)
Source: Green Building Research Laboratory (GBRL)

SP1=Typical Washed Rock Roof Membrane Cover (151.5F)
SP2=High Albedo (.75) White Roof (110.0F)
SP3=Low Albedo (.10est.) dark roof, NE Exposure (135.0F)
SP4=Low Albedo (.10est.) dark roof, SW Exposure (144.0F)
SP5=3-month Old Green Roof (Essentially Bare Soil) (100.0F)

GrID: Many of our readers would like to know if green roofs can reduce energy use in buildings and if so, by how much? What factors most influence the outcome? What light has your research been able to shed on this pressing question?

Dr. Sailor: The thermal performance of green roofs depends on a number of factors. Specifically, roof construction, depth and properties of the growing media – including soil moisture, plant characteristics and coverage, and local climate characteristics all affect heat transfer into the building. The role of the roof on building energy consumption also depends on internal building loads and schedules. An often overlooked point is that the performance of any alternative technology depends on the baseline that is used for the comparison. As a result, I hesitate to assign a specific level of savings that could be expected from green roof implementation. That said, the various simulations that we have conducted for cities across the US have shown that a green roof can have comparable summertime air conditioning benefits to those achieved by white or “cool” roofs. In contrast to a cool roof, however, the added thermal insulation of a green roof can result in a wintertime heating energy savings whereas the cool roof generally has a wintertime heating penalty. In general, our model shows that the annual air conditioning energy savings associated with replacing a typical roof with a green roof are on the order of 100 to 500 kWh for each 1,000 sq. ft of green roof. What is important to note, however, is that the energy savings are just one component to be considered in determining the economic and environmental value of green roofs. It is likely that the stormwater, urban heat island, and extended roof life aspects of green roofs are equally important.

GrID: The energy savings for green roofs are more modest than I would have expected. I remember some of your findings displayed at the 2007 Green Roof for Healthy Cities conference in Minneapolis had energy saving ranges between 4-12% depending on the location.

Dr. Sailor: Yes, the air conditioning energy savings by themselves are modest. The numbers I gave above are just for the Air Conditioning savings. Heating savings can be comparable or more important depending upon the location and roof design.

The data that you recall from the Minneapolis meeting were specified in terms of HVAC savings. The numbers from that poster were 3-6% annual cooling electricity savings in Minneapolis, 2-5% for Phoenix, and 3% in Orlando. For heating energy savings we had found up to 10-14% for Orlando and Phoenix, and about 4% for Minneapolis. While the model has changed some, these values are generally consistent with what we are still finding.

The nominal ranges that I described from our current model simulations are for a green roof in comparison to a roof that has an albedo of 30%. Both roofs are assumed to be insulated to modern energy code standards. The actual savings depend very much on the baseline used for comparison with the current tool providing a conservative estimate that might significantly underestimate savings for some applications. Also, it should be noted, that depending upon soil depth, vegetative lushness, local climate, and building type, a green roof can actually INCREASE the energy cost for heating or cooling in a building. The tool can provide the necessary feedback to avoid such a situation, and then help you move toward an optimum design with respect to total energy performance.

GrID: Oftentimes, engineers modeling the energy use of a building find it difficult to accurately simulate the effects of green roofs on energy use. Can you tell our readers about the plug-in your have created for the Department of Energy’s (DOE) EnergyPlus modeling software? How has this enabled mechanical engineers to more accurately model the effects of green roofs? How widely used is it?

Dr. Sailor: We developed a physically-based model of the energy balance of a vegetated roof and integrated this model into EnergyPlus. This module is now a part of the standard release of EnergyPlus and allows the energy modeler to explore how variations in green roof design can impact whole building energy performance. It is hard for me to assess how widely used it is among practitioners in the field, but I have been contacted by multiple groups around the US who are now gearing up to use the model in their research and design work.

GrID: If the impact green roofs have on energy use in a building is as modest as you describe, why would you need to model the green roof? Are there cases where it can/has make/made a significant difference?

Dr. Sailor: As I mentioned previously, if one does not pay attention to the green roof design from an energy standpoint, the roof may perform WORSE than a conventional roof. The tool can help the user avoid such potentially undesirable outcomes and then be used to optimize the design for improving energy performance beyond a conventional design. In the case of a retrofit the existing roof insulation may be significantly lower than current code or the current membrane may be much darker than the 30% reflective baseline that I use in the modeling. In such cases, the actual energy savings of the retrofit may be much larger than that reported directly in the current version of the calculator. Nevertheless, the calculator can be used to optimize the energy performance of the new roof.

GrID: What do you see as the future of green infrastructure?

Dr. Sailor: I think that historically there has been a bit of inertia within the building industry that tends to limit the pace of innovation and application of new concepts. From the perspective of an academic researcher I see great opportunities for applied research to develop new technologies and the data and modeling tools necessary to understand the building performance implications of these technologies. Green roofs and walls are technologies that are both promising, and receiving increased interest in recent years. In order for green infrastructure to reach its full potential, however, it is important to develop the tools and data needed to fully evaluate their many co-benefits.

-Brian Phelps


-Green Roof Energy Calculator

-Mitigation Impact Screening Tool


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 (, 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.


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


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.

Kansas City Stormwater Overflow Control Plan

4 12 2009

Source: Kansas City, Missouri Overflow Control Plan Overview Document

This year Kansas City embarked on a massive $2.3 billion stormwater overflow control plan to address sewer overflows throughout the city. Its inclusion of a major $28 million green infrastructure pilot project has gained a lot of attention. The project has been recognized as the largest green infrastructure project in the United States. The Marlborough Neighborhood Pilot Project, as it is called, is located in the Middle Blue River Basin, one of the four major watersheds addressed by the plan. The entire pilot project encompasses nearly 100 acres of primarily residential neighborhoods. This program is anticipated to be expanded over a larger 744 acre area that will eventually include over 25 acres of mixed green infrastructure strategies (i.e. rain gardens, bioswales, permeable pavement, and green roofs) that have the capacity to sequester 3.5 million gallons of water. The green infrastructure strategies employed are designed to replace two underground tanks of similar capacity. In total the pilot project and its expansion are budgeted to cost $68 million.

Video of compiled images from Mark O’Hara’s Greenbuild Presentation about the Kansas City Plan. The video shows various Green Infrastructure Strategies recommended in the plan. Video compiled by Hawkins Partners Images provided by BNIM (Click here to see it if  video is not present)

In addition to the Marlborough Neighborhood Pilot Project, the plan also recommends the enhancement of the area’s highly acclaimed 10,000 Rain Garden Program. Over the past two years, the initiative is reported to have installed several hundred rain gardens, bioswales, and rain barrels. The purpose of the expansion it to develop an incentive program to accelerate the program’s progress and complement the public investments being made.

Wet retention basin projects have been identified as an appropriate strategy for treating stormwater downstream from six separated sewer system (SSS). The plan acknowledges that green infrastructure is beneficial and should be included where it is practical. The plan states:

“Every decision should be viewed as an opportunity to incorporate a green-solutions approach. The City has adopted an “every drop counts” philosophy, meaning it is important to reduce stormwater entering the system wherever practicable. This will be accomplished through changing the way the community develops and redevelops its sewer and stormwater infrastructure, educating citizens regarding steps they can take to reduce the amount of stormwater entering the sewer system, enabling citizens to take those steps, incorporating green infrastructure in the design of public infrastructure, and making targeted public investments in green infrastructure projects early in the Plan implementation.”

Areas identified that should be considered for green infrastructure projects include those meeting the following criteria:

  • Areas for which no or minimal conventional structural controls are proposed.
  • Areas in which widespread implementation of green solutions by the community at large offer the greatest opportunities for reducing the size and cost of conventional structural controls included in the Plan.
  • Areas for which it would be particularly desirable to further reduce the projected overflow
    activation frequency following completion of recommended controls.
  • Areas in which sewer separation is proposed but where no Water Services Department (WSD) investment in treating the separate stormwater runoff has been included in the Plan.
  • The plan’s ambitious Marlborough Neighborhood Pilot Project is very encouraging, particularly as a stand alone project. It is very significant and the City should be commended for their efforts. However based on the $2.3 billion budget established by the plan, it is evident that green infrastructure will play a supporting role. The plan was developed during the recent significant shift in the way we address stormwater management across the country over the last few years. It is not surprise to see this. What is encouraging is the magnitude of the pilot project and the extensive monitoring that will be conducted.

    The monitoring component will provide valuable data for the City and others across the country. In addition to understanding green infrastructure’s effectiveness to control Combined Sewer Overflows (CSOs) and improving water quality, monitoring it will provide insight into conflicts with local codes and ordinance, social-economic benefits, construction techniques, associated cost, and maintenance practices.

    The plan stresses that it is an evolutionary document, referring to it as an “adaptive management” approach. The approach involves evaluation of the strategy throughout the life of the project based on their experiences and data gathered through the monitoring efforts. While green infrastructure may not be the predominant tool of choice at this point, the longer-term nature of the plan provides the opportunity to adjust its course as confidence increases in green infrastructure. The City’s plan can become more green overtime as it builds upon its successes.

    Fairly or unfairly, like many pilot projects much rests on the success of the Marlborough Neighborhood Pilot Project. Many, both locally and nationally will be watching it with great interest. Failure of such a high profile project could significantly set back the growth of green infrastructure as the stormwater management tool of choice. Therefore, it is critical it is done to the highest standards possible. The project will serve as an example for those involved in stormwater planning and design to have full confidence and understanding of the complexities of utilizing natural systems. Natural processes are complex making them more difficult to quantify. A paper prepared in 2007 by the Center for Neighborhood Technology titled “Managing Urban Stormwater with Green Infrastructure: Case Studies of Five U.S. Local Governments”, identified the lack of performance data as a barrier to green infrastructure implementation. The more research we do and data we collect the better off we will all be.

    I anticipate this will be a successful demonstration of green infrastructure. It is exciting to see another city embrace green infrastructure on such a large scale. We will all eagerly await the results and follow its realization. Construction is expected to start soon.

    -Brian Phelps