GI In Seattle: The Importance of Pilot Project Success For All Green Infrastructure

4 01 2012

Image
Ballard Roadside Rain Gardens, Credit: Seattle Public Utilities

The City of Seattle was one of the early pioneers of utilizing green infrastructure as a stormwater best management practice with projects primarily concentrated on reducing stormwater flows in various creek basins. Over the last few years, the City has turned its attention to using green infrastructure for controlling Combined Sewer Overflows (CSOs) within the city. While there is currently no consent decree, the City has established a control target of one untreated overflow per outfall per year for CSO discharged based on a 5-year rolling average (Washington Administrative Code (WAC) 173-245). The highest priority for these efforts has been overflows within Lake Washington. Green infrastructure practices are estimated to contribute to this target by controlling 12% of the 16 million gallons needed to be addressed to achieve the City’s goal. The remaining portion will be controlled by conventional grey infrastructure strategies.

The Ballard Roadside Rain Gardens was the first green infrastructure project designed specifically for controlling CSOs. The $1.4 million pilot project was funded by an American Reinvestment and Recovery Act (ARRA) loan and involved installing a series of rain gardens in the right-of-way along eight blocks in the Ballard neighborhood. The rain gardens were installed in December of 2010 and with the expectation that they would reduce discharge volumes by 59,000 gallons or 1% of the the total within the specic NPDES basin. Unfortunately, many of these rain gardens did not perform as anticipated. As a result, over the last few months the project has received negative press and vocal neighborhood opposition over their performance.

The City conducted an extensive post-construction analysis, and determined  a third of the rain gardens were not draining and another third were underperforming. The main shortcoming identified was that the geotechnical analysis conducted prior to construction was not specific to each rain garden location and therefore could not account for subtle changes in their infiltration rates. As a result, the underperforming rain gardens did not have sufficient infiltration rates to drain within twenty-four hours and underdrains were not used.

After the post-construction evaluation and a comprehensive community outreach effort, the City took corrective action. The public’s main issues included the dangers of standing water (i.e. drowning, mosquito habitat, smell), steep side slopes of the rain gardens, and their overall aesthetics. The corrective action included removing several of the rain gardens, reducing the depths and steepness of side slopes of others, and adding underdrains where they were effective. These changes resulted in reducing the original estimated CSO volume control by 36%.

The City went further and identified recommendations to improve future implementation of green infrastructure projects. Some examples of their recommendations included the following:

Community Engagement

  • Get out into the community early
  • Introduce the problem you are trying to solve, before you present the solution
  • Utilize several communication media to disseminate information and get feedback.

Planning

  • Develop a Project Management Plan (PMP) that outlines roles and responsibilities, schedule, budget, and risks that is approved by management.

Geotechnical

  • Integrate geotechnical engineers into all phases of the project and empower them to speak up.
  • If the corrected (design) infiltration rate is between 0.25 and 0.5 inches per hour, build a redundant system into the design, such as an underdrain.

Design

  • Provide the design for the flow control/bypass plan and erosion and sediment control plan. Do not leave it to the contractor.
  • Review project design, how it functions, and the critical project components with Construction Management ahead of time.

Construction

  • Balance funding sources with the ability to course correct during construction and the documentation requirements.
  • Involve geotechnical engineers in construction to field verify that the excavated or exposed soil look as anticipated.
  • Maintain an open dialogue between contractor, construction management, project manager, designer, and geotechincial engineer.

The City of Seattle should be commended for recognizing the shortcomings of the project and taking quick corrective action. The project serves as a reminder of how important the success of pilot projects are to the future of green infrastructure not only locally but also nationally. News travels fast and high profile failures can cast doubt on the effectiveness of these types of systems and fuel future opposition to projects. When approaching any green infrastructure project, the details and execution are crucial to a project’s success, but when the project is intended to set the standard and introduce the public to green infrastructure practices, it becomes even more critical.

-Brian Phelps

Sources:
Email interview with Shanti Colwell, Environmental Engineer with Seattle Public Utilities
Seattle Public Utilities Case Study
Ballard Roadside Raingardens, Phase I-Lessons Learned





479 Green Infrastructure Case Studies Released

30 09 2011

The American Society of Landscape Architects recently released 479 Green Infrastructure Case Studies. The case studies provide an informative snapshot of the type of green infrastructures are being implemented across the country. We are excited the two projects we submitted (The Pinnacle at Symphony Place green roof and Deaderick Green Street) were included in the list. You can check out the entire list here.

-Brian Phelps





Quantifying the Financial Value of the Soft Benefits of Green Roofs

6 05 2011

Steven Peck, Hon. ASLA, and Founder and President of Green Roofs for Healthy Cities was recently interviewed by The DIRT while in Washington D.C. for the Living Architecture Symposium, (“Despite the Economy, Green Roofs Bloom“). In the interview, Mr. Peck quoted a recent survey of the green roof industry  which reported that 8-9 million square feet of green roofs were built last year. This figure represented a 30% increase in market growth. Most of this expansion was focused in cities that have public policies in place that encourage and support green roof installation. The most intriguing statements in the article are those that helped quantify the economic impact of green roofs.

The post included some assertions that quantified the financial value of some of the soft benefits of green roofs. These included

“…average stormwater mitigation benefit is $4.26/sf” and  a view of a green roof improves property values of nearby buildings by 11%”

These figures are based on research by Smart Cities Research Services, Montreal.  “The Monetary Value of the Soft Benefits of Green Roofs” report prepared by Ray Tomalty, Ph.D. and Bartek Komorowski, MUP with the assistance of Dany Doiron, published last year. The report includes research on developing heuristic methods for quantifying seven soft benefits of green roofs: including: change in property values, marketing benefits, food production and food security, sound attenuation, stormwater retention, air quality, and green house gas (GHG) sequestration. The following is a summary of their findings:

I did not include the marketing figures in the table above, due the complexity of their findings.

Since there is little to no research specific to green roofs, the heuristic methods described in the report rely on other related research. Examples include:

Supply and demand play a critical role in determining one values and this is not any different for green infrastructure. For urban areas that may incorporate little to no green infrastructure (i.e. parks, green roofs, street trees) and are predominantly unsightly parking lots and roofs, projects that include green roofs should be more valuable and those properties surrounding it should benefit in some way as well. The report provides a great starting point for financially quantifying the soft benefits of green roofs. Over time, data specific to green roofs will eventually become available and we will be able to more accurately quantify their specific benefits.

-Brian Phelps





Bike Share Programs

18 06 2010

I’ve known about bike share programs for sometime, but hadn’t really thought of them recently until I visited Menominee, a small town in Michigan’s upper peninsula. Menominee, population about 9,200, is located on the western shore of Lake Michigan; is has a nice marina and a small airport a few miles inland. I noticed bike racks full of yellow bikes and a few people riding them around town too. I learned that the city’s bike share program (they call it the Yellow Bike Program) has been in place for four years now. It was started completely by volunteers of the local Rotary Club and donated bikes in a effort to promote tourism. Today the program includes 47 bikes spread around the city at various community locations, such as the airport, marina, history museum and library.

One of the first bike share program in the US was started in Portland, OR in 1994. The program simply released bicycles into the city for unrestrictive use, but proved unsuccessful due to theft and vandalism. Other cities such as Madison, WI tried similar programs, but eventually modified to a more restrictive system requiring deposits for use of the bicycles. Washington DC instituted the first high-tech European style bike share program in the US in 2008, called SmartBike DC.
Montreal has the largest bike sharing program in North America, called Bixi. In 2009 the system had some 400 stations where bicycles can be rented with a credit card, there are over 5000 bicycles in the system. The system has had so much success that Washington DC/Arlington is also adopting the Bixi program, as well as Washington State University. This particular program offers varied pay scales from $5/day to $78/year. Pretty reasonable if you live or work in the city and have the need to use a bicycle. By the way, Menominee’s Yellow Bike program is completely free, you just need to show your drivers license and leave a phone number, the advantage of a small town.

There are many other bike share program in cities throughout the US, the Bike-sharing Blog has a lot of additional links and information if interested. Also, something to be aware of in the coming months,  Nashville has plans to start its own bike share program soon.

-Sara Putney

Yellow Bikes at Menominee Airport





Ecological Importance of Southeastern Rivers

10 03 2010

Interpretive signs for an upcoming project near the Harpeth River in Williamson County will highlight the ecological significance of the waters of the southeastern United States. If you didn’t know, the rivers and streams of middle Tennessee are part of the most unique and diverse freshwater ecosystem in the entire world. This has to do with a couple things, namely the temperate climate combined with the fact that much of the area was unglaciated, or it as been more geologically stable than other parts of the U.S.

Just to give you an idea the area is home to more than 250 species of crayfish (70% of all the species in the entire U.S.), more than 300 species of mussels (over 1/3 of these live in Tennessee), and more than half the freshwater fish species in the U.S. Because of this great diversity, Tennessee has more freshwater fish that are at-risk than any other state. These species are at-risk largely due to pressures from development practices, which allow sediments and pollutants to wash into our rivers and streams. This and other topics concerning protection of critical watersheds can be found in, Rivers of Life or States of the Union: Ranking America’s Biodiversity, just some of the publications found on the NatureServe’s website.

Graphic from 'Rivers of Life', published by NatureServe

As mentioned in an earlier post, the implementation of ‘green street’ practices on Deaderick Street in downtown Nashville will divert approximately 1.2 million gallons of stormwater a year from the Cumberland River. This is water that would have otherwise run unabated into the river carrying all of the pollutants and sediments from the street. Understanding the significance of the region’s biodiversity is a good reminder of what we are trying to protect when implementing green infrastructure planning and strategies –and why this is especially important here in the Southeast and Middle Tennessee.

-Sara Putney





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





Finding Water in the Desert

22 01 2010

There have been a few articles lately about the new Underwood Family Sonoran Landscape Laboratory which is a part of the School of Landscape Architecture at University of Arizona. Arizona is known for its arid climate, but this project uses an innovative take on irrigation to provide a lush landscape for this jewel of a space.

Photo Courtesy of Ten Eyck Landscape Architects Inc
Photo by: Bill Timmerman

In addition to creating a wetlands biome, complete with an 18,000 gallon pond, the project provides an 11,600 gallon cistern for water harvesting. The water harvesting is provided from four sources – and rainwater is not the largest source of water. Of the approximately 250,000 gallons of water harvested each year about 40% comes from condensate from the air conditioning units, 33% comes from rainwater runoff from the roof, 18% from well water blow off and 9% from greywater collection (from sinks and drinking fountains. This water harvesting accounts for 83% of the water required for the landscape on an annual basis.

Photo Courtesy of Ten Eyck Landscape Architects Inc
Photo by: Bill Timmerman

In addition to the water harvesting, the garden includes a significant green wall with planted vines adding to the shading from the hot desert sun on the southern façade of the building.

Next up, they are looking at creating a desert green roof which can be monitored for research data.

If this is available in a desert environment, think of the potentials for harvested water elsewhere.

University of Arizona News had an article about the facility that provides more information on the project. Check out their photo of the large water collection system in action. Ten Eyck Landscape Architects were the landscape architects for the project.

Photo Courtesy of Ten Eyck Landscape Architects Inc
Photo by: Bill Timmerman

Photo Courtesy of Ten Eyck Landscape Architects Inc
Photo by: Bill Timmerman

-Kim Hawkin