June 16, 2011 | General

Climate Change Connections: The Green Way

BioCycle June 2011, Vol. 52, No. 6, p. 59
Sally Brown

THERE is an organization in Washington State called the Mountains to Sound Greenway Trust ( Its purpose is to conserve and enhance the Interstate 90 corridor, from the Puget Sound through the Cascade mountains, as a beautiful green stretch of working forests and farms (ergo, the Greenway). This is accomplished through a combination of public and private partnerships. I drive this corridor many weekends and can tell you that it is very successful.
The Mountain To Sounds Greenway (MTSG) is the brainchild of Jim Ellis, one of those gifts that every urban area should be lucky enough to have. Mr. Ellis is retired now and working on an autobiography, but I have been fortunate enough to hear him tell the story of the Greenway. He got this idea, “a crazy idea” he says, and realized that he would need some heavy hitting partners to make it work. So he called some of his friends during lunchtime, when he knew that they would be at their desks and their staff would be at lunch. He scored close to 100 percent, Bill Gates being the exception, and the Greenway was born. Boeing and Weyerhaeuser were two of the original partners, with Microsoft coming in after Bill eventually returned the call. Jim’s primary goal in starting the Greenway was to preserve open space near the urban core. To him, open space keeps cities more livable.
My direct connection to the Greenway is local use of biosolids. King County, where Seattle is located, is the largest biosolids generator in the region. Jim realized that using biosolids locally was a way to create an urban-rural partnership that would serve to strengthen both partners. For this area, the rural partnership ended up being commercial forests, both public and privately owned.
As part of my job, I go to the commercial Douglas-fir plantations and prescribe application rates for biosolids to fertilize the trees. There are thousands of acres in tree farms around the area and when you drive on I-90, you are looking at commercial forests, fertilized and kept profitable in part by the biosolids from King County. A local use for the biosolids has helped King County out as well. And it has also helped out countless numbers of drivers and hikers who look out at beautiful scenery instead of subdivisions.
Jim also strongly felt that the value of preserving green space and forests went well beyond the spreadsheets for the timber companies. To that end, he funded a graduate student, Andrew Trlica, with the goal of quantifying benefits associated with maintaining greenspace around urban areas. Andrew’s research centered on calculating soil carbon storage for land restored to forestry with composts and biosolids (over 100 Mg CO2/hectare; see “Measuring Carbon Storage In Biosolids-Amended Mine Land,” November 2010). However, he also included other benefits, and found that restoration would result in a greater provision of ecosystem services including storage and filtering of over 646 millions liters of water per hectare over a 30 year period, with tourism revenue of up to $30,000 for that same piece of land. Since Andrew finished his thesis, articles have come out documenting improvements in public health as a result of people’s exposure to natural settings.

I’ll be hosting the president of the Soil Science Society of America and the Society’s Washington, DC representative here in Seattle to show them the importance of soil science in urban areas. Thinking of their trip and what they should see, who they should talk to, it occurred to me that it would be great to introduce them to Jim Ellis. But what would they talk about? There aren’t too many cities with commercial tree plantations around them. Not many cities where you can see both mountains and water while standing in just one place. It wouldn’t make sense to introduce them to Jim because the MTSG is such a Seattle specific institution.
And then it hit me. Many of the goals of the MTSG are applicable to all cities, mountains, sound or not. One of the basic tenets of the program was to preserve open space near urban areas. One of the ways that Jim attempted to do this was by integrating use of biosolids in the commercial forestry industry. This was seen as a way to enhance profitability for the forestry industry while simultaneously reducing costs for the municipality. All cities have organic residuals. Using these residuals, and here I mean biosolids, yard trimmings and food scraps, to enhance green infrastructure has the potential to create more open space within urban environments while simultaneously improving the bottom line for multiple divisions within city governments.
This again you say. I’ve spent a number of columns talking about the importance of integrating use of locally generated residuals into urban infrastructure. Community gardens are one logical area. Green infrastructure for storm water management is another. For each case, you are taking some of the central tenets of the MTSG program and applying them to your local municipality. In each case there will be multiple benefits. And thanks to a link provided by Nora Goldstein, it may be possible to start quantifying these benefits.
Nora pointed me to the Center for Neighborhood Technology (CNT) in Chicago, in particular its new guide, Value of Green Infrastructure, for calculating the benefits of green infrastructure ( The guide provides quantitative values for green infrastructure, including green roofs, tree plantings and bioswales. In my last column I provided numbers for the greenhouse gas (GHG) reduction associated with diverting food waste and yard trimmings from landfills. Say that those materials were composted instead of landfilled – you saw what the benefits were.
Now take it the next step. Say that those composts were used to create bioswales for enhanced storm water capture and filtration. First off, you would likely see benefits in the bottom line for many municipalities for not paying tipping fees for landfilling and then having to outsource bids for compost. For the purposes of this column, let’s just call that a wash. Then using CNT’s green infrastructure economics, we can talk about the additional benefits.

One example in the guide crunches the numbers for bioretention and infiltration. The authors used an example of a site in Chicago that retains 80 percent of storm water runoff with an infiltration area of 2,000 ft2 and a drainage area of 4,000 ft2. Total water savings is 114,000 gallons (based on annual precipitation of 38 inches). Treating those 114,000 gallons as storm water at the local wastewater treatment plant would have cost about $10.50 each year. (The example used a treatment cost of $0.0000919/gallon.) Remember, we are talking about one little bioretention system. Reducing the flow into these plants results in avoided capital costs for building new treatment capacity. One city estimated it costs $2.71/ft2 in infrastructure costs to manage the storm water generated from impervious areas. So the 6,000 ft2 bioretention system, with 80 percent capture, goes from a capital cost of $16,000 to $3,240.
This is for treatment facilities. For the infrastructure costs of moving the storm water to the treatment plant, savings are estimated at $340/developed acre in one study and $100,000 to $235,000 per city block in another, On top of all of this you have increased real estate values for two things – lower risk of flooding and enhanced neighborhood appearances. Here the range of improvement in property values is 2 to 7 percent.
Reduced quantities of water to treat means reduced power used to treat the water. For that same bioretention system, associated energy savings estimates range from 130 to 285 kWh. That can translate into additional carbon credits, as can the carbon sequestered in the compost amended soils and the healthy biomass growing in the soils.
The CNT study also discusses reduced heat island effect and increased community livability. Prettier places get people to go outside and walk around more. An estimated health savings associated with exercising more as a result of a prettier environment was over $800/individual. Other benefits are discussed including improved wildlife habitat, community cohesion and enhanced environmental awareness.
By using these indices, it becomes clear that not only can the Mountains to Sound Greenway model be adopted by all municipalities, it can provide a green alternative, both environmentally and economically to current engineered systems. As climate change brings us more extreme storm events, it may prove to be the best option that we have available.
That Jim Ellis is a very smart man. I think that I’ll see if he might have time to meet with the guys from the Soil Science Society.

Sally Brown, Research Associate Professor at the University of Washington in Seattle, authors this regular column. E-mail Dr. Brown at slb@u.washington. edu.

Sign up