March 19, 2008 | General

Don't Treat Building Site Soil Like Dirt

BioCycle March 2008, Vol. 49, No. 3, p. 23
Outreach campaign and website in Washington State, which specifies amending soil with compost, is changing standard building practices.
David McDonald and Kris Beatty

THE Washington Organic Recycling Council (WORC), which started the Soils for Salmon project in 1999, launched a new website,, and a “Building Soil” outreach campaign to change standard building practices. The mission is to help builders and developers preserve and restore native soil on building sites, using compost. These soil “best management practices” (BMPs) will soon be required by local governments around western Washington, as local codes are updated. The Building Soil campaign helps builders get ahead of the new regulations, and change site practices now to satisfy their customers.
Native forests in western Washington soak rainfall quickly down into the groundwater, with little runoff. However, during construction projects soils are often stripped and compacted, resulting in rapid runoff that damages streams and downstream properties. The 1999 listing of Puget Sound Chinook salmon as threatened under the Endangered Species Act was a wake-up call to citizens and regulators that “business as usual” had to change. WORC’s Soils for Salmon project started working for change: training engineers, planners and designers, talking to regulators and building professionals to create a practical solution. The Soils for Salmon team helped the State Department of Ecology write a “Post-Construction Soil Quality and Depth” BMP that would require builders to either preserve native soil and vegetation where possible, or restore healthy soil functions by breaking up compaction and tilling in compost.
That soil BMP will soon legally come into effect, as local towns and counties adopt it into their storm water regulations. New municipal storm water permits, issued by the State Department of Ecology in February 2007, now require the soil BMP. But regulatory wheels grind very slowly, and the best way to help get the soil BMP adopted around western Washington turns out to be educating builders to “just do it” now.
There are several reasons for builders to foster healthy soil, including: More marketable buildings and landscapes; Better site erosion control; Reduced need for water and chemicals; Less storm water runoff, better water quality; and Healthy landscapes equal satisfied customers.
The Building Soil campaign recently mailed a flyer (available on the website) to all 8,000 builders, developers, grading contractors, landscape architects and civil engineers in western Washington. The story is spreading, with coverage in building, landscape and erosion control professional publications. An email push also has reached local storm water planners, with the goal of building momentum for local adoption of the soil BMP. This campaign is built on years of work with building professionals and depends on providing high-quality information that builders need, in formats that are easy for them to use – hence the new website, which is just for builders.
Construction site erosion control can now be accomplished using the U.S. Environmental Protection Agency’s approved compost blanket, berm and sock BMPs (see the website for a factsheet). Spreading two to three inches of compost as a “blanket” provides the required erosion protection during construction. At the end of the project, the compost can just be tilled in to create a healthy planting soil, or planted through on slopes too steep to till. This also saves the expense of removing other types of erosion covers. Compost berms or socks often perform better than conventional silt fence or straw bales, and again, the compost can just be knocked down and tilled in or left on site. This two-for-one value of compost as erosion control and soil amendment is helping convince builders it can be a cost-effective addition to their standard building practices.
Key to this effort has been building professionals who take ownership of the soil quality and erosion BMPs, and sell them to their peers. “These soil practices work better than anything we’ve tried – plants survive the first winter, and slopes don’t need to be fixed later,” says Jim Berger, Construction Manager for Port Blakely Communities. “It’s a key part of our sustainable building program. Using compost blankets on slopes and compost soil amendments throughout the project not only prevents erosion right away, it gives us great vegetation establishment, even on difficult sites.” A building consultant, Jeff Cox, ASLA, of Triad Associates, confirms this stance. “Placing amended soils or stockpiling topsoils has front-end costs, but there can be long-term savings and benefits, from healthier plant material, better growing medium and water quality improvements,” says Cox.
Howard Stenn, a site planning consultant (and Soils for Salmon team member), notes that preservation of undisturbed vegetation will save storm water detention, landscaping and development costs. “Compost soil amendment makes for quicker planting and faster plant establishment,” explains Stenn. “There’s no doubt these practices help sell a project.” Jim Thompson, a Shamrock Heights homeowner, agrees. “It adds value to the home now while we live in it, and for the future when we sell,” says Thompson. “I think it adds great value to the community too.”
Around the country, storm water codes are starting to include soil quality and other “Low Impact Development” (LID) practices that use compost, like bioretention swales and rain gardens. Considering the significant amount of land area covered by urban and suburban development, there is a great market opportunity for the organics recycling industry – selling compost and mulch for storm water management. One avenue, which can be utilized anywhere, would be to get involved with local planners and builders. Lead with preserving existing soils wherever possible, and then show the value of restoring construction-impacted soils with compost.
As Margaret Mead famously noted, small groups of committed people are the only thing that ever has changed the world. In the last 10 years, the Soils for Salmon project has convinced many building, design and government professionals around the nation not to treat the soil like dirt. One exciting success is the incorporation of the soil BMPs into the new “Sustainable Sites” initiative of the American Society of Landscape Architects and the US Green Building Council (USGBC). The Sustainable Sites criteria will eventually be incorporated into the USGBC’s “LEED” green building standards, which are transforming construction around America.
WORC’s website will continue to offer the latest on the background science, specifications and tools for design professionals. But this new Building Soil website and campaign are designed to help builders get the specific information they need to succeed, and as follow-up, more builder trainings around the region will be conducted. Check it all out at
David McDonald is a Resource Conservation Planner for Seattle Public Utilities. Kris Beatty is a Program Manager for King County Solid Waste Division. This article draws on the work of the Soils for Salmon team over the last 10 years.
Soils For Salmon Update
BACKGROUND and history of the Soils for Salmon project can be found in these BioCycle articles: “Organics Play Role In Salmon Recovery In Pacific Northwest,” (April 2000); “Composting Advances In Oregon And Washington,” (February 2001); “Organics Recycling Initiatives Spawned By Salmon Recovery,” (September 2001); “Best Management Practices For Postconstruction Soils,” (February 2004); “Soil Restoration with Organics Enters Mainstream of Storm Water Practices,” (April 2005); and “Building Soils for Storm water Compliance and Successful Landscapes,” (March 2007).
Five Steps To Building Soil
Best management practices (BMPs) during construction:
1. Retain and protect native topsoil and vegetation where practical.
2. Restore disturbed soils to restore healthy soil functions by:
o Stockpiling and reusing good quality site soil, or
o Tilling 2 to 3 inches of compost into poor site soils, or
o Bringing in 8 inches of compost-amended topsoil.
3. Loosen compacted subsoil, if needed, by ripping to 12-inch depth.
4. Mulch landscape beds after planting.
5. Protect restored soils from erosion or recompaction by heavy equipment.

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