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In the heart of Stillwater, where the St. Croix River meanders through the historic town, there lies a network of over 400 public rain gardens. These unassuming green spaces serve a vital purpose—mitigating the unfiltered runoff of stormwater and meltwater that would otherwise cascade across impermeable surfaces and find its way into creeks, lakes, and rivers.
The meticulous design of these rain gardens involves excavating the basins and replacing the native clay with a porous mix of sand and silt. The result is a depth of several inches to a foot of soil, strategically engineered to capture and filter runoff effectively. But there's more to these rain gardens than meets the eye.
Beyond their primary function, the rain gardens in Stillwater play a crucial role in revitalizing the local food web. Insects, the unsung heroes of ecosystems, have specific dietary requirements. Our Minnesota insects, it turns out, are quite discerning eaters. They prefer native plants over exotic species that hail from distant corners of the globe. This selectivity creates a challenge for our insect populations when faced with non-native flora.
Enter the rain gardens, where the planting choices, while not exclusively native, lean heavily towards local plant species. Some of these plants emerge as superstar hosts, providing food and shelter for a diverse array of vulnerable insect larvae. The ripple effect extends to the avian residents of Stillwater, as birds rely on insects as a primary food source. By consciously selecting native plants for our rain gardens, we are actively mending the delicate fabric of our local food web.
FIND OUT WHAT INSECTS CAN BE FOUND IN RAIN GARDENS:
Sustainable Stillwater MN has taken up the mantle of caring for some of the oldest rain gardens in town. The Rain Garden Workgroup, a dedicated team within our organization, is at the forefront of this initiative. Guided by the expertise of the Washington County Watershed Management District, these stewards have learned that rain gardens, like any infrastructure, have a finite lifespan. Over time, the basins accumulate silt from drain inlets, reducing their effectiveness.
In response, the Rain Garden Workgroup, led by Ruth Alliband, is embarking on a re-evaluation of the oldest rain gardens. This process involves identifying which gardens continue to excel in capturing runoff and warrant rejuvenation. The chosen rain gardens will undergo a literal transformation—re-trenched and replenished with fresh, porous soil. Once revitalized, these green havens will continue to serve the Watershed Management District and the Stillwater community.
ADOPT A RAIN GARDEN IN 2024:
However, not all rain gardens will continue their service. Some will gracefully retire from their duties but will persist in adding charm to the streets and sidewalks of Stillwater. In their retirement, they will still contribute to the food web, reminding us that even as nature evolves, the symbiotic relationship between plants, insects, and birds remains a timeless dance.
As we witness the cycle of renewal for Stillwater's rain gardens, let it serve as a reminder of our responsibility to nurture and sustain the delicate ecosystems that surround us. In the quiet corners of our towns, Sustainable Stillwater MN stands as a green ambassador, silently working to mend the threads of our interconnected natural world.