Philly Recieves Approval for Green Infrastructure Plan

3 06 2011

Philadelphia’s Green City, Clean Waters Plan ,submitted to the EPA last September, has been signed by the PA Department of the Environmental Protection (PADEP) and the Philadelphia Water Department (PWD). According to PDW’s press release, it happened on June 1st. The approval of the plan is a big step in furthering green infrastructure’s legitimacy as a tool to address stormwater issues. The following are links to past post about the plan:

Triple Bottom Line of Green Infrastructure

Philadelphia Green Infrastructure Video

-Brian Phelps


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Categories : Plans and studies, Sustainable Site Strategies

Clarifying EPA’s Jurisdiction Under The Clean Water Act

3 03 2010

Supreme Court Building
Credit: istockphoto.com/diademimages

On Monday the New York Times ran an interesting article as a part of their Toxic Waters series. The article titled “Rulings Restrict Clean Water Act, Foiling E.P.A.” reported on the difficulties regulators are having implementing the intent of the 1972 Clean Water Act. The difficulties stem from the Supreme Court’s decision in 2008 questioning the definition of  “navigable waters” in Rapanos v United States and Carabell v United States Corp of Engineers. The court was split (4-1-4) on whether the wetlands in question were under the jurisdiction of the Clean Water Act since they were not directly adjacent to a navigable waterway.

The Clean Water Restoration Act (text here) introduced into Congress last year by Senator Russ Fiengold, D-Wisconsin and Rep. Jim Oberstar, D-Minnesota seeks to clarify this definition. Clarifying the definitions of the EPA’s jurisdiction would facilitate the implementation of the Clean Water Act and allow regulators to make decisions. The bill has passed the Senate Environmental and Public Works Committee, but has been placed on hold by Senator Mike Crapo, R-Idaho.

I am curious about the timing of the NYT article and wonder if there will be any action on the Clean Water Restoration Act in the near future. Obviously, the decision could have a profound impact on the EPA’s jurisdiction.

For more information I came across this analysis of Rapanos v United States and Carabell v United States Corp of Engineers from the Harvard Environmental Law Review. You can also find the EPA’s current clarifications on “Waters of the United States” on their website here.

-Brian Phelps


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Categories : water issues

Getting the Facts: Monitoring Green Infrastructure

8 01 2010

In Wednesday’s post, I mentioned the benefits of monitoring to help explain the reasons why green infrastructure facilities are being employed in their neighborhoods and specifically their effectiveness in improving water quality in our rivers and stream for which we all depend.

The City of Portland has done a great job at monitoring their green streets and other green infrastructure facilities. They provide this information on the Bureau of Environmental Services’ (BES) website. Their 2008 evaluation of their green street facilities have shown that for a 25-year storm event ( 25-yr, 6-hr) that peak flows were reduced by 80% or more. For CSO compliance events, their studies were shown to capture 60% or more of the storm volume.

It appears less has been published by the City on the pollutant removal capabilities for green streets. However, as mentioned in the article, studies conducted across the country have shown bioretention areas, the main stormwater management component of a green street, have been shown to be very effective. EPA’s fact sheet on bioretention shows the following removal rates:

  • Total Phosphorous: 70%-83%
  • Metals (Copper, Zinc, Lead): 93%-98%
  • Total Kjehldahl Nitrogen (TKN): 68%-80%
  • Total Suspended Solids: 90%
  • Organics: 90%
  • Bacteria: 90%

These number continue to be supported through researched conducted over the last decade. The concern that the accumulation of these pollutants, particularly metals will pose health risk have been unsubstantiated. A four-year study by Philip Jones (student) and Dr. Allan Davis (advisor) at the University of Maryland, showed the level of pollutants that accumulated within a bioretention cell on campus to exceed soil background levels but were far below EPA cleanup standards.

It is important to remember that currently, most conventional stormwater devices have no capacity to address pollutant removal. Portland is at the forefront in implementing green infrastructure practices and will be well positioned as Federal standards continue to be strengthened over the coming decade. More importantly, they are improving the water quality of their rivers for future citizens.

If fact, the EPA recently announced they are conducting stakeholder input in an effort to initiate a national rulemaking that would establish a comprehensive program to reduce stormwater discharges from new development and redevelopment and make other regulatory improvements to strengthen its stormwater program. At a minimum the EPA intends to propose a rule to control stormwater from newly developed and redeveloped sites, and to take final action no later than November 2012.

-Brian Phelps


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Categories : Bioretention, Green Street

EPA’s Green Infrastructure Statement of Intent

28 12 2009


Structured Rain Garden at
Tennessee Association of Realtors, Nashville, TN

In 2007, the Environmental Protection Agency (EPA) issued a Statement of Intent that recognized the viability of green infrastructure as a legitimate and effective tool that can be used to protect our water sources from non-point source pollutants. The statement was signed by the National Association of Clean Water Agencies, Natural Resources Defense Council, Low Impact Development Center, and the Association of State and Interstate Water Pollution Control Administrators. The objectives of the statement included the following (direct excerpt from Statement of Intent):

  • Affirm the belief by the signatory organizations in the value of green infrastructure as both a cost effective and an environmentally preferable approach to reduce stormwater and other excess flows entering combined or separate sewer systems in combination with, or in lieu of, centralized hard infrastructure solutions
  • Establish a framework for working together to advance an understanding of green infrastructure as a tool for reducing overflows from sewer systems and stormwater
  • Identify partnership opportunities between the signatory organizations
  • Develop strategies to promote the use of green infrastructure by cities and utilities as an effective and feasible means of reducing stormwater pollution and sewer overflows such as:

-Developing models for all components of green infrastructure and make them available nationwide.

-Exploring opportunities and incentives for the use of green infrastructure provisions in MS4 permits and CSO Long Term Control Plans (LTCPs), including as a component of injunctive relief provisions of enforcement actions

-Developing memoranda and guidance materials, including language for the NPDES permit writer’s manual, that would explain how regulatory and enforcement officials should evaluate and provide appropriate credit for the use of green infrastructure in meeting Clean Water Act requirements

-Recognizing the most effective and innovative uses of green infrastructure to meet Clean Water Act goals through EPA awards or recognition programs

-Providing technical assistance, training, and outreach to potential users of green infrastructure, including states, cities, counties, utilities, environmental and public health agencies, engineers, architects, landscape architects, planners and nongovernmental organizations

-Establishing a web-based green infrastructure resource center at EPA to assist communities in complying with requirements for combined sewer overflows and municipal stormwater permits and evaluating the multiple environmental benefits that green infrastructure can provide

-Developing tools to assist local green infrastructure programs with outreach, training, model development and application, planning and design, monitoring, and plan review

It has been almost three years since this statement was released. In that time, we have come a long way. There has been a tremendous increase in attention to green infrastructure within municipalitie’s overflow control plans and integration of best management practices into city stormwater manuals. We have gone from having to convince municipalities to employ green infrastructure practices, to being encouraged to use them by the same agencies. With Philadelphia proposing an all green infrastructure solution to the EPA for addressing the city’s overflow plan, it will be interesting to see how the EPA responds.

A recent New York Times’ article, “City’s ‘All Green’ Stormwater Plan Raises Eyebrows at EPA” underscored the unique approach the City of Philadelphia is taking. I thought Howard Neukrug summed it up well. He was quoted as saying:

“We recognized that if we manage stormwater where it lands, whether on the ground or on a roof, that in very many circumstances we can not only prevent that gallon of water from overflowing, but we may be able to find additional benefits for our customers…Things that impact the urban heat island effect, things that improve the aesthetic of a community.”

As we enter this new decade, we can be assured that green infrastructure will increasingly be a part of the solution.

-Brian Phelps


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Categories : Sustainable Site Strategies

EPA to test porous pavement and raingarden benefits

11 11 2009

1700 Charlotte
1700 Charlotte in Nashville
Combines Porous Concrete & Bioswales

Traditional asphalt parking lots may seem to be the most cost efficient, but underlying costs such as increased pollution and water load on our sewer systems need to be considered as well. In an attempt to measure those underlying costs the EPA has replaced nearly 43,000 SF of their traditional asphalt parking with 3 different types of permeable pavement systems and several raingardens with different planted vegetation. At their Edison, NJ facility they will conduct a decade long study to evaluate and document the performances of these permeable systems on the basis of removing pollutants and filtering capabilities. Having these systems all in the same location will likely result in more balanced testing of each material.

This study comes at an ideal time as many cities are beginning to re-evaluate old paving methods in order to reduce the load on existing sewer systems or just to reduce the amount of toxin runoff from paved surfaces to our nearby rivers and lakes. Traditional asphalt parking lots collect oil, grease and other debris over time, after a heavy rain or snowstorm these toxins are washed from the parking surface to the nearest storm drain or permeable surface. Replacing this impervious surface with a permeable pavement or raingarden will allow plants and soils to naturally filter the pollutants, while re-charging the ground water table.

Porous for Blog
Porous Concrete

-Will Marth


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Categories : Bioretention, Pervious Pavement, Sustainable Site Strategies

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


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Categories : Green roof, Uncategorized