Grass-porous pavement provides alternative to asphalt for Hillsboro Unitarian Universalists.
What to do. The congregation didn’t like the idea of creating a large paved parking lot that would be used primarily only one day a week. That’s when the congregation’s history of supporting environmental issues came to the rescue. After some research the congregation decided the best solution was not to pave at all, but to use something called “GrassPave2.” In short, GrassPave2 is a foundation of compacted gravel overlaid with a plastic grid, which is filled with sand. Grass is sown in the sand and with the right amount of fertilizer and water a durable grass parking lot is created.
The congregation got busy this summer—much of the work was done by crews of church members—and the new green lot got its first workout Sunday, October 21. “It's terrific,” said the Rev. Christine Riley. “We are thrilled that choosing to embrace the challenge of environmental sustainability has led to such a delightful result.”
Unitarian Universalists are guided by seven principles. The seventh one, which is focused on environmentalism, is “Respect for the interdependent web of all existence of which we are a part.”
Church member Allan Warrior, lead coordinator of the project, said it took a bit of convincing to get the city to approve the new type of parking lot, but now city officials and other public officials from around the area are watching to determine if GrassPave2 might be used in other places, rather than paving over more land. At the moment the church has the largest GrassPave2 lot in Oregon, said Warrior.
The 37-vehicle lot cost $84,000. Warrior said that’s probably more expensive than asphalt. He doesn’t know how it compares to concrete, since that wasn’t an option the church considered. And with either asphalt or concrete the church would have been required to pay for treatment for any runoff water. “Now we have a lot that provides its own filtration and there’s no runoff,” said Warrior.
GrassPave is a product of Invisible Structures (see Related Resources below for a link). Warrior explained that the parking lot was first excavated a foot deep. A porous “geocloth” was laid down and covered with six inches of gravel and then a three-inch layer of smaller gravel. After that was thoroughly compacted a one-inch thick grid made of recycled plastic was laid down. Enough sand was poured to just cover the grid. After the sand was compacted grass was planted in the sand. Fertilizer and water did the rest.
This type of parking surface only works in low traffic areas. That makes it ideal for churches that have heavy traffic on Sundays and light traffic during the week. And the church’s neighbors love it, Warrior said. “They came over and said, ‘Gee you guys are really nice neighbors.’” Grass areas also generate less heat than concrete or asphalt. The surface is said to be able to support any street-legal vehicle including heavy trucks, said Warrior. The company claims a 60-year life span for its plastic grid.
The church is in a historic neighborhood in Hillsboro, which is a suburb of Portland. Warrior said the church in effect created a small park with the new parking area. “We’ve created islands in the parking lot on which we’re going to plant native plants.”
The surface requires careful attention to watering and fertilizer. All grass clippings, leaves, and other vegetation has to be removed to prevent thatch buildup, which would impede drainage. The clippings go onto the church’s compost pile. Snow plowing is out. That would be a drawback in some areas of the country, but not in Hillsboro.
Riley said the congregation is very focused on sustainability. “We have several certified Master Gardeners, and we teach recycling and sustainable gardening to the wider community.” The congregation is also a “Green Sanctuary,” a designation awarded by the Unitarian Universalist Ministry for Earth to congregations that raise environmental awareness, choose sustainable practices, and work on environmental justice issues in their communities.
Riley said she is looking forward to sharing with visitors “how this project is supportive of our liberal religious faith and a demonstration of the ways that humans can positively interrelate with the Web of Life.”
She added, “I think UUs have both an opportunity and an obligation to let folks in the wider community who are looking for ways to live greener lives know that there is a church that has a long history of supporting that. Our movement has long walked its talk, going all the way back to Thoreau, but the message is just not out there as much as it could be.
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Donald E. Skinner was the founding editor of the InterConnections newsletter for congregational leaders and a senior editor of UU World from 1998 until his retirement in 2014. He is a member of the Shawnee Mission Unitarian Universalist Church in Lenexa, Kansas.
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