Cascadia College Rain Garden

Five yards of bioretention soil mix were purchased from Cedar Grove using the WaterWorks grant. Tyson Kemper picked up the order and brought it to the site. At first it was shoveled in by hand, but it was apparent that it would be easier if the truck was backed up and the bed was tipped, pouring the soil mix directly into the prepared site. Once the soil was in place it was smoothed out and a border of rocks was added.  Excavated soil mixed with compost and sand were used to build the berm around the garden. The inner area would eventually be shaped into a bowl with a 6" depth. The final berm is about a foot high and two feet wide, giving the garden an 18" depth before rain will overflow from the site.

Soil at the site was very difficult to remove. The top 8" consisted of a thin layer of sod, under which was gravel and clay. It took five people with a pick-axe and shovels three hours to remove it. The next 8" were removed by the rain garden designer alone, since it consisted of red clay with larger round rocks and did not require a pick-axe. At the bottom of this layer, the ground was moist from recent rain and pools were forming in depressions. The bottom 8" was extremely difficult to remove and required a pick-axe and plenty of patience. At this point the ground had dried, leaving a stubborn horizon of rocky blue clay. Completing the last leg of the excavation project was timed until after a rain shower, since that made the soil easier to work with. After the excavation was completed to 24" depth the base was carefully graded so that it was perfectly level and flat. The irrigation pipe was found about 15" below the surface and was very carefully e

To test the suitability of a site for the installation of a rain garden, a test pit must first be dug to measure the infiltration rate of the soil. This test pit was 6" by 6" and 24" deep. The infiltration rate was close to one inch per hour, which is sufficient for the installation of a rain garden.

Tyson Kemper, the facilities supervisor, took the Capstone Project student and advisor on a tour of potential sites for a demonstration rain garden that could be placed on the campus. The Truly House was chosen because it is at a prominent spot along a path used by students, faculty, neighbors, and visitors. It is between the Cascadia College campus and University of Washington Bothell, and it is behind a historical building, which enhances the positive association between rain gardens and residential lawns. This should promote the idea that rain gardens enhance the appearance of a property. It was also on a spot that has had a flooding problem due to compacted clay soils and needed a green infrastructure solution. It was possible to locate the garden near a downspout that drains stormwater from the roof while keeping it far enough from the building's foundation, and it was also possible to install it without disturbing the landscaping already present, which were other important

The Bachelor of Applied Science in Sustainable Practices program is a way to get a four-year degree learning to apply principles of green energy, sustainable agriculture, green infrastructure, biodiversity, green building design, and business practices that give back to the community while respecting natural resources. This program is taught in a college with a committed faculty and small class sizes that allow for plenty of hands-on learning. Learn more about this program  here . The creator of the rain garden started by getting an Associates in Environmental Technology and Sustainable Practices at Cascadia. Entrance requirements accept 90 college credits from a variety of disciplines that transfer into the Bachelor's program. Once admitted, a cohort-style takes the student on a two-year journey through the history and philosophy of sustainability, the science of sustainable practices, and the business and policy approaches that will help the sustainability perspective change soci