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Rain garden another learning tool for Olalla students
The students congregated near the playground area at Olalla Elementary School, each stepping carefully into the fresh soil with a green plant in hand.
But that marked more than just the culmination of a monthlong beautification project.
Kitsap Conservation District rain garden program manager Teresa Brooks said the one placed on top of a slope overlooking the school’s baseball field will serve as “an educational rain garden.”
“We’re trying to teach the next generation how important proper stormwater management is,” said Brooks, adding that students will be able to measure how much water is collected in the rain garden, which she estimates is 20 feet by 20 feet.
The idea behind the rain garden was spurred by Olalla second-grade teacher Lisa Wickens. Since 1987, Olalla teacher Greg Guariz has run a program where students raise and release chum and coho salmon into Olalla Creek. Along with the opportunity to enhance an area that previously featured scattered gravel, Wickens saw the potential to extend the school’s longterm commitment to protecting the creek.
“It’s much bigger than just the rain garden,” she said. “This school is really the center of our community because it’s such a small, little town. There’s a lot of community buy-in. It’s a community service project because it really does protect our creek.”
That particularly is important now as this area receives most of its rainfall in December. According to weather.com, Port Orchard averages more than 10 inches of rainfall this month.
“Kitsap gets most of its water from precipitation events,” Brooks said. “Right now a lot of the water just goes by surface and really quickly gets to the ditches. The ditches usually go to a stream. The water is rushing down really quickly and flooding out the stream ruining salmon habitat and whatnot.”
But erosion is not the only stormwater-related issue.
“When the water moves quickly over the surface it collects a lot of pollutants,” Brooks said. “Oils, all kinds of heavy metals and things from brake dust and carries it right into Puget Sound. It ruins our shellfish habitats and our lakes.”
This marked the 100th rain garden Brooks helped create since she developed the county’s program in 2010. Brooks said she has studied the work of Curtis Hinman, adjunct associate professor and extension educator at Washington State University. He researches and implements low-impact development stormwater management.
Brooks said Hinman and WSU students have studied the soil created for rain gardens, which is created from 60 percent sand and 40 percent compost.
“That’s a matrix that will clean water that has been studied at WSU,” she said. “They figured out a good mix that will really clean the water.”
But first, Brooks had to find an ideal location to place the rain garden. She determined the area just off the playground nestled near a slope made the most sense.
“This water was coming off the hard surface,” Brooks said. “We’ve placed the rain garden strategically to catch all of that water. Allow that water to soak into the ground. It slows it down, soaks it onto the property that created it and returns the water to the groundwater system and recharges aquifers. It also reduces flooding downhill slopes.”
With assistance from Abba Construction, Brooks said they excavated about two feet before laying the new soil. The natural soil then was placed around the edge of the rain garden to create a berm. Along with the new soil, several plants, including compact dogwoods, Oregon grapes, snowberry, red-flowering currants and tufted hairgrass, are strategically placed into three separate zones of the rain garden. Brooks said these plants — and their roots — are designed to clean the water.
“It will probably pond about 6 inches,” she said. “If we get an enormous rain event — like a 100-year rain event — it’s possible that the overflow will be used.”
Brooks worked on the Olalla project at no cost to the school and also has assisted several homeowners and businesses in unincorporated Kitsap County. During the last three years, Kitsap Conservation District has provided 50 percent grants of up to $500 each for people to purchase materials and construct their own rain gardens. That amount will increase to $1,000 next year, and will enable homeowners to use other stormwater-control methods, such as pervious pavement, rain barrels, soaker trenches, landscaping and lawn treatments — as long as that reduces runoff.
“Rain gardens have such a nice look to them that people really receive them well,” she said. “Homeowners are willing to put some money to put some in because aesthetically they’re pleasing.”
One of Wickens’ students, Ethan Edwards, recently had a rain garden constructed at his house.
“It’s very good for the environment,” Edwards said. “It’s nice.”
Wickens, who said the Kitsap Conservation District provided books with plants used in rain gardens for students, hopes to construct another one in front of the school later in the school year.
“We’re just trying to get our kids feeling environmental and being proactive with the environment,” she said. “Everyone wins.”