Olympic Sized Green Roof

17 02 2010

Courtesy Vancouver Convention Centre website

The winter Olympics just kicked off with the opening ceremonies from BC Place Stadium in Vancouver. But serving as the International Broadcasting hub for the games is the Vancouver Convention Centre — the world’s first LEED Canada Platinum rated convention building. The 1.2 million SF center boasts a 6-acre green roof, which also now makes it the largest green roof in North America.

The roof is planted with over 400,000 native plants and collects rainwater for irrigation which contributes to the buildings stormwater credits as well. Other interesting sustainable features include marine and shoreline habitat restoration. Fish habitat was actually built into the buildings foundations. The building also uses seawater for heating and cooling and incorporates on-site water treatment.

The following video “Vancouver’s 6 Acre Living Green Roof”, posted on You Tube gives a great sense of the scale and context of the green roof. The landscape architect who worked on the project, Bruce Hemstock, discusses the plants used, soil media and the idea behind habitat linking into urban centers that is beginning to be made possible with the inclusion of more green roof in our cities. Interestingly enough he says one of the biggest challenges of the project was initially convincing people that it was the right thing to do.





Interview with Dr. Allen P. Davis, P.E. Part 2 of 2

15 02 2010

Bioretention at Mercury View Lofts Parking. Nashville, TN
Source: Hawkins Partners, Inc. ©2010

The following is the second part of my email interview with Dr. Allen P. Davis, P.E. the Director of the Maryland Water Resource Research Center at the University of Maryland. Dr. Davis is a leading researcher on bioretention and has published numerous studies quantifying the benefits of its use in urbanized watersheds and low impact development (LID) concepts. In 1993, he received the National Science Foundation Young Investigator Award.

Green Infrastructure Digest: One of the many benefits of bioretention is that it addresses quality of the run-off. How effective are bioretention areas at removing common pollutants (i.e. suspended solids, metals, pathogens, thermal heat gain) and to what extent?

Dr. Allen P. Davis: Bioretention, as with most stormwater practices, addresses water quality through both volume management and pollutant treatment. So first, it is important to reduce runoff volume, which will have an overall beneficial impact on all respective pollutant loads. On the treatment side, we have significant data showing excellent removal of suspended solids and metals. Solids are effectively filtered by the bioretention media. Metals are captured with solids, as some are particulate bound. Also, bioretention media has a significant capacity for metals adsorption. Hydrocarbons are adsorbed and we have data indicating that they are readily biodegraded. Research by us and others have shown some removal of pathogens, although pathogen concentrations in runoff vary by many orders of magnitude throughout the year, making quantification difficult. Dr. Bill Hunt at North Carolina State has shown some thermal mitigation through bioretention media.

As mentioned above, removal of nitrogen and phosphorus is found, but this is highly variable from site to site and is media dependent. Very low concentrations of phosphorus are targeted for water quality protection. The performance of bioretention for phosphorus will depend on the source and characteristics of the soil used for the bioretention media. Some soils will have relatively high native concentrations of phosphorus. These media will perform poorly and may even export the excess nutrient.

Bioretention is probably least effective for nitrate and chloride, both anions. Some nitrate may be taken up by a thick stand of vegetation. In snowy areas, chlorides, as deicing agents, may be applied to roadways and parking lots at very high levels. Chlorides are minimally held by bioretention media and will pass through, though not immediately, to surface and ground waters.

GrID: When designing bioretention facilities, what factors have the most impact on their success (i.e. soils, soil depths, slope, plant material, infiltration rates)? Why?

Dr. Davis: First, the answer to this question depends on how you define success. We are trying to come up with a good set of performance metrics to define success. Is it to replicate the hydrology, water quality, and habitat of a pre-existing forested area? If so, the bar is set very (unrealistically?) high. I don’t think we’ll be able to completely replicate the forested watershed. Hydrologically, we can attempt to manage volumes and flow rates, and couple these with groundwater and baseflow recharge. We can exploit various physical, chemical, and biological processes for water quality improvement.

That said, what we are finding is that design and site factors have different impacts on different performance metrics. For volume and flow management, bigger is better (deeper media, greater surface area), and greater infiltrating surrounding soils will always help. Capture of metals, suspended solids, and some toxic organics varies little with design parameters. They are readily filtered and adsorbed on the surface of the media. Nutrients have very complex fate pathways. We haven’t gotten a full handle on these pollutants and it appears that most of your listed design and site parameters will affect their removal.

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

Dr. Davis: We’re still working against a lot of inertia. As we continue to install, understand, and learn, green infrastructure will become more prevalent. We continue to need more demonstrations, more performance data. Each implementation will make the next one easier. Regulations and codes need to be updated to allow the inclusion of novel technologies, where we have the science to back it up. As alluded to above, we must understand the fundamentals of how these various green technologies perform. They are not “black boxes” that we can stick a performance number on. Each is a complex combination of an engineered and natural system. We will continue to take advantage of their capabilities, but also look for design and operational modifications to improve performances. We should be able to tailor specific designs and design characteristics to the specific needs of a watershed.

Part 1

-Brian Phelps





Interview with Dr. Allen P. Davis, P.E. Part 1 of 2

12 02 2010

Bioretention Diagram
Source: Hawkins Partners, Inc. ©2010

The following is an email interview with Dr. Allen P. Davis, P.E. the Director of the Maryland Water Resource Research Center at the University of Maryland. Dr. Davis is a leading researcher on bioretention and has published numerous studies quantifying the benefits of its use in urbanized watersheds and low impact development (LID) concepts. In 1993, he received the National Science Foundation Young Investigator Award.

Green Infrastructure Digest (GrID): Over the last 20 years, you and your department have been instrumental in building the current body of knowledge regarding the design and effectiveness of bioretention systems to address stormwater run-off in urban areas. In regard to your current stormwater research, what issues are you and your department studying? Beyond your current projects, what are the issues that you think need to be studied in the coming years?

Dr. Allen P. Davis: While we find bioretention to be effective in the management of urban runoff, we still have many unanswered questions and opportunities for improvement. First, we need to be able to quantify performance results. Bioretention systems are all not the same, we should not expect each of them to perform identically, and our (and others) research show that they don’t. Bioretention performance will depend upon the characteristics of the contributing watershed and surrounding soils/hydrogeology, surface area, media depth, placement of underdrains, media characteristics, flow patterns, vegetation, and other factors. As we better understand the fundamentals of bioretention, we can better predict the effects of these parameters, leading to better designs and more effective watershed management.

Additionally, we are interested in improving the performance of bioretention in removing nitrogen and phosphorus compounds. These nutrients are the pollutants of primary concern for many water bodies, certainly for us in the Chesapeake Bay watershed. Bioretention performance for these nutrients is marginal and modifications to standard designs are being investigated to improve N and P removal.

The list for research topics is very long: what are the fates of captured pollutants? what is the role of biological processes (hydrocarbon degradation, plant uptake, nitrification/denitrification)? what are the best vegetation and vegetation management practices?

GriD: Over the past few years, green stormwater infrastructure has increasingly been employed within various Cities’ stormwater overflow control plans. As you know, bioretention is one of the dominant tools within the green infrastructure toolbox. Are bioretention facilities an effective tool for reducing stormwater run-off particularly in CSO events within our urbanized areas? If so, what impact has your research or others been able to demonstrate? If not, why?

Dr. Davis: Bioretention clearly can play a role in stormwater volume reduction. The larger the bioretention facility, the greater the reduction. CSOs present a greater challenge than suburban bioretention because of the lack of available land in cities. Some creative thinking can help to improve infiltration and storage in highly urbanized areas, but this is a major challenge. Some cities are looking to expand green space, even through opening up vacant lots for stormwater management. This can be helpful, but must be done on a large scale to show meaningful results.

Part 2-Monday

-Brian Phelps





Pervious Concrete and Solar Reflectance

10 02 2010

Pervious Concrete A=20% Fly Ash Mix B=50% Slag Mix
Center of the photo is the stalite base of the concrete

Our office was invited to tour the Tennessee Concrete Association’s (TCA) new headquarters in Nashville. The focus of the tour was to learn more about their experience with pervious concrete. They had a few examples of pervious concrete pours on site, and I thought the one in the photograph above was particularly interesting. TCA is experimenting with mixes to increase the Solar Reflectance Index (SRI) value of pervious concrete. Mix A in the left side of the photograph is a pervious concrete mix that replaces 20% of the required cementitious content with fly ash. Mix B to the right has replaced 50% of the required cementitious content with slag. Both substitutes are by-products of industrial process. Fly ash is from the process of burning coal for energy and slag is from the production of both iron and steel.

As you can see there is a noticeable difference in the color between the two samples. The slag sample is much lighter in color. We were told it was difficult to determine the SRI of pervious concrete due to the voids. As a result, TCA could not definitively tell us the SRI value. They are interested in finding someone to perform more testing.

In regard to cost, TCA stated the slag is readily available in Tennessee but not all producers carry it. Fly Ash is the less expensive option compared with cement and slag, but slag is typically less expensive than cement (especially white cement)

It does appear the slag mix  provides a great option to improve solar reflectance. I hope more data will be available in the near future that supports this.

-Brian Phelps





Interview with Portland BES Part 3 of 3

8 02 2010

Mt. Tabor Middle School Rain Garden
Source: City of Portland, Environmental Services ©2009

The following is the third and final 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): When it comes to new construction or public projects, it is much easier to require and/or encourage the use of green infrastructure best management practices. Existing development has proven to be much harder, what strategies has the City used to encourage existing developments to retrofit their properties to include green infrastructure and reduce/cleanse stormwater runoff?

Ms. Emily Hauth:

  • Downspout Disconnection Program (1995- present) – Disconnecting downspouts from the sewer system allows roof water to drain to lawns and gardens. Downspouts on many homes are connected directly to the combined sewer system and disconnecting them keeps clean stormwater runoff out of the combined sewer system, which reduces CSO volume. Over 56,000 downspouts have been disconnected since the program began 15 years ago
  • Community Watershed Stewardship Program (1995-present) – provides grants of up to $10,000 to schools, churches, businesses and other community organizations for projects that connect people with watersheds and protect and enhance watershed health.
  • Willamette Stormwater Control Program (2001-2003) – The city offered financial grants and technical support for several projects to retrofit existing commercial properties served by the combined sewer. This was to research the feasibility, cost and performance of commercial sustainable stormwater approaches. The city distributed about $350,000 to 11 projects.
  • Innovative Wet Weather Program (2002-) – promotes stormwater management projects that contribute to healthy Portland watersheds. Between 2002 and 2005, the U.S. Environmental Protection Agency (EPA) granted the city $2.6 million to fund over 25 innovative public and private projects throughout the city that demonstrate sustainable, low-impact stormwater management solutions.
  • Clean River Rewards (2006-present) – a stormwater utility discount program for private property owners who manage stormwater on their property. They can receive a discount of up to 100% of their on-site stormwater management charge.
  • Grey to Green Program (2008-) – The city offers incentives of up to $5 per square foot to add new ecoroofs. The city also offers treebates to encourage people to plant eligible yard trees. The treebate is a credit on the recipient’s sewer bill of up to $40 per tree ($50 for native species).
  • Private Property Retrofit Program (2009-) – The Tabor to the River Program offers design assistance and construction dollars for on-site stormwater management on targeted private properties. The program is available only in areas where stormwater retrofits will allow the city to avoid more costly sewer replacement projects. The city will install rain gardens, stormwater planters, swales or ecoroofs on sites that meet program criteria at no cost to the property owner. Property owners who want to install a facility themselves could qualify to receive financial incentives and technical assistance.
  • WorkingGreenPortland.com (2009-) – includes information on private property stormwater management technique, calculators to determine impacts for individual properties, and links to stormwater retrofit professionals and other resources.
  • Ecoroof Floor Area Ratio Bonus – Development proposals in the central city that include a green roof, can receive bonus floor area.
  • Education and Outreach – Numerous efforts to engage communities and increase public understanding and acceptance are critical to the success of all city programs.
  • Technical Assistance – the city offers technical assistance to professionals and property owners for implementation of sustainable stormwater management approaches.

12th Avenue Green Street
Source: City of Portland, Environmental Services ©2009

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

Ms. Hauth: I would say future green infrastructure in our urban environment will include:

  • Green connectors – streets that connect parks and open space, schools, and commercial areas to neighborhoods; encourage walking and biking by providing enhanced and safer pedestrian and/or bicycle routes; and provide environmental benefits.
  • Green refuges within our urban environment – reclaiming unused spaces or derelict sites within our cities for stormwater management and passive recreation.
  • Ecodistricts – integrated neighborhoods that capture, manage, and reuse a majority of energy, water, and waste on site; offer a range of transportation options; provide a rich diversity of habitat and open space; and enhance community engagement and well-being.
  • Volunteer Green Street Maintenance Program – engaging community members to help in the care and maintenance of green streets.
  • Possible onsite stormwater management discount to property owners for adjacent public green streets.
  • Cost benefit analysis of the ecosystem services provided by green infrastructure in meeting the triple bottom line.

For more information visit our wesbite

If you missed the first parts of the interview, you can find them here.

Part 1

Part 2

-Brian Phelps





Interview with Portland BES Part 2 of 3

5 02 2010

Green Street Curb Extension at SE 12th and Clay
(Gateway to the Clay Street green connector)
Source: City of Portland, Environmental Services ©2009

The following is the second 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. She would like to credit Tim Kurtz, engineer at BES with the following responses.

Green Infrastructure Digest (GrID): What role do green streets play in the City’s overall stormwater management strategy, particularly their role in addressing stormwater overflows in your CSO districts as compared to the big pipe projects (i.e. Columbia Slough Big Pipe, East Side Big Pipe, West Side Big Pipe)? What lessons have you learned over the course of implementing your green streets projects?

Mr. Tim Kurtz: Our CSO control program began in 1991. We are completing construction of our third large CSO tunnel to help us complete the program by the mandated deadline of 2011. But several projects to reduce CSO volume by removing stormwater from the combined sewer system are very important to the CSO control effort. For example, we have disconnected thousands of downspouts from the combined sewer system since 1995. It’s a relatively low-cost CSO solution but it’s a major part of our green infrastructure. Downspout disconnections remove more than 1.2-billion gallons of stormwater annually from the combined sewer system.

Green streets will play an important role in ensuring that our new CSO tunnels remain under capacity as new growth and development increase stormwater volume in the future.

Green streets also help alleviate basement flooding from sewer backups in neighborhoods with combined sewers; they are a good alternative to sumps and sedimentation manholes, and they are an important tool in meeting water quality requirements in Portland’s urban streams.

We use Green Streets and other stormwater management facilities to meet different needs such as improved water quality, flow control, and complete infiltration. We’ve learned that soils can be a determining factor in how our facilities are constructed to meet our different goals. On Portland’s east side, soils typically meet our infiltration rates (>= 2 “per hour) but often require underground rock storage to meet complete disposal goals. On the city’s west side, where soils are much tighter, we typically line facilities to meet water quality goals.

Monitoring green street function has been important in proving that they work and that green infrastructure makes good fiscal sense. In the 2.5 square mile Tabor to the River Program area, green streets save us money. The original estimate using traditional grey infrastructure was $144 million in today’s dollars. Two years later, the program was re-designed with a combination of grey and green infrastructure. The current estimate for this integrated approach is $81 million. Through monitoring we’ve also evaluated and modified design components to improve function. We’ve realized economies of scale with larger project areas. We’ve also created guidelines for green street construction practices, recognizing that incorrect soil types and compacted soils can hinder green street function

GrID: With the recent Portland Tribune article regarding the 44th Avenue and Seymour Street Green Street Project, what is your process for implementing a green street project? To what extent do you involve the public in the design/location of the facilities?

Mr. Kurtz: The outreach process for green street implementation always includes property owners affected by a green street facility. With all projects, we meet with adjacent property owners, attend neighborhood and business association meetings, offer presentations to groups, distribute informational publications and host green street tours.

  • At 30% design, the city sends information to adjacent residents for small projects or all project area residents for larger projects.
  • At 90% design, the city mails notification to all project area residents of upcoming construction.
  • Depending on project needs and priority, there may be flexibility in facility type and location. But the city determines the final design to meet system needs.
  • Adjacent property owners can choose from a set of planting templates, with the opportunity for some customization.

The public has responded positively to this hands-on approach to explain the benefits and cost savings of green streets. More than 100 citizens have called to ask the city to install a green street facility next to their homes. Of course, not all property owners are supportive, as is the case along SW 44th and Seymour. We view this public process also as an opportunity to receive feedback, both negative and positive, and work to address the issues.

Back to Part 1

Part 3-Monday

Flow Test Monitoring of Green Street in Portland
Source: City of Portland, Environmental Services ©2009

-Brian Phelps





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





Trees and Their Impact on Economic Development

1 02 2010

Hill Center Green Hills, Nashville, TN

A discussion was started on the ASLA LinkedIn group last week regarding street trees’ impact on retail districts. The discussion centered on Professor Kathleen Wolf’’s research. Professor Wolf is a Research Social Scientist in the University of Washington’s College of Forest Resources Department. She has been at the forefront of the research being conducted in this area. Like the landscape architect who started the conversation, I have also been wondering if anyone has taken her research a step further. Professor Wolf’s research relies on user surveys that include both visual preference surveys and traditional questionnaires that ask respondents to rate environments and/or their willingness to pay more for a product.

In an Arborist News article published last year, Dr. Wolf reported on the work she has been doing. In the article, she reports that across all categories, places rated steadily higher with the increased presence of trees. Larger trees rated higher than smaller trees. Her surveys that looked at product pricing within districts with trees indicated that customers are willing to pay 9 percent more in smaller cities and 12 percent more in larger cities.

In her response to an emailed question posted on LinkedIn, she explains that she does not suggest that trees are the panacea for other business challenges and that there is not a simple casual link between having trees and increased revenues. Street trees and streetscapes are positive reinforcement of the “atmospherics” that market researchers consider to have influence on consumer’s buying habits.

I agree that street trees and streetscapes do add a considerable amount to the ambiance and character of place that people enjoy. Anecdotally, I think most people can understand the impact trees have on how we feel in a space/district. However, since retail success can be very sensitive to location and surrounding demographics, it can be difficult to make a clear connection between retail sales and trees. I hope that research continues to make the case, and like the sophisticated interior research done by market researchers, we can continue to increase our understanding of this relationship.

The article in Arborist News also offered some guidelines on street trees in retail districts such as the proper tree species, size, maintenance, and providing signage that contrasts with the trees’ foliage. I would add that tree placement along the street and their relationships to the doors, windows, and dividing walls between businesses are also important to consider.

The reports on Professor Wolf’s website Human Dimensions of Urban Forestry and Urban Greening are worth checking out.

-Brian Phelps





Toronto’s Green Roof Requirements Take Effect Monday

29 01 2010

Downtown Toronto
Photo Credit: istockphoto.com/benedek

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





Power of Plants: Phytoremediation in Action

25 01 2010

photo credit: istockphoto.com/mtr

Over the last decade, I have been fascinated with the remediation of contaminants using plants and related biological processes. I was first introduced to the concept by a story on NPR about the use of poplar trees to remediate groundwater contamination. The Corp of Engineers has been involved in successfully implementing and researching these techniques for some time now.

This weekend I came across an audio recording of a lecture by Eli Cohen, the director of Ayala Water and Ecology, on the Freshkills Park Blog. AW&E is an engineering firm based in Moshav Zippori, Israel. Their organization has been involved in a number of impressive phytoremediation projects. The lecture including questions and answers is just over an hour. The link on the Freshkills Park Blog to the pdf of his slides is broken, but I was able to find it here. I recommend using it to follow along.

The presentation only touches the surface of the phytoremediation capabilities of the plants and processes in AW&E’s projects and leaves you wanting to know more. Despite this, the implementation of the concepts provides a great opportunity to see the potential of this strategy to address serious contamination issues. Every day green infrastructure projects are filtering and remediating stormwater runoff. It is interesting to see similar concepts being used to tackle industrial clean up and other difficult environmental problems.

-Brian Phelps