Rain gardens are an effective solution for improving water quality, while also enhancing the natural beauty and biodiversity of the local environment. Yet, their primary role is effectively capturing and managing stormwater runoff before it enters local waterways or water management systems.
Properly designed rain gardens are functional points of personal and community interest. Choosing native plants that are suited for our Oklahoma climate serves to attract and support their natural partners, birds, and bees that help to pollinate plants and help to balance unwanted pests.
#1. Designing and Building Rain Gardens
When designing a rain garden, it’s important to select plants that can thrive in wet conditions. Native plants are excellent choices, as they are adapted to the local climate and can help support local biodiversity. Yet, their potentially more desirable cousins should prove to be equally suited to the project, provided the soil is well-drained and enhanced with organic matter for supporting plant life and stormwater runoff.
The size of a rain garden will depend on the size of the property, the amount of rainfall expected rainfall and the natural or created slope of the property that will affect the speed with which water will be exiting the property. As a rule, a rain garden should be designed to capture and treat runoff from at least 10% of the impervious surface area on the property. This can be calculated using online calculators or consulting with a landscape professional.
Once the design is finalized, construction can begin. The area where the rain garden will be located should be excavated to a depth of about 2-3 feet, and the soil should be amended with the appropriate mixture of sand and organic matter. The rain garden should be shaped with a slight depression in the center to encourage water to temporarily pool to nourish plants. Over time, the natural evolution of root systems and decay of leaves and the like will serve as a mulch to retain moisture and suppress weed growth.
#2. Improving and Sustaining Water Quality
Stormwater runoff flows over non-porous surfaces such as roofs, sidewalks, and parking lots gathering pollutants. Think of your rain garden as an intermediate step in that process to cleanse that water at least partially for its ultimate destination.
By directing stormwater runoff into a rain garden, the water can infiltrate into the soil, where it can be naturally filtered and treated by the plants and soil microbes. This process can remove up to 90% of pollutants from the runoff before it enters local waterways. In addition, the plants in a rain garden can absorb and utilize excess nutrients, further reducing the amount of pollutants that enter the water system.
In some parts of the United States, such as Minnesota, this process is regulated by state and local municipalities to preserve the general water quality of the collective region of lakes and waterways. Large and small rain gardens pick up and process pollutants such as oil, fertilizer, and pet waste to minimize its impact on aquatic habitats.
#3. Maximizing Rain Garden Biodiversity
Rain gardens can support a variety of plant and animal species, thereby enhancing the biodiversity of the collective environment. The native plants commonly used in rain gardens have become welcome contributors to the health and well-being of the community at large.
Unlike many cultivated forbs, shrubs, and grasses, native plants have evolved for centuries to thrive in demanding climate and soil conditions with minimal care. These qualities make them well-suited for rain gardens, especially in public spaces where the care is expected to be minimal.
In addition to supporting plant and animal species, rain gardens can also serve as important habitat corridors, allowing wildlife to move freely between fragmented habitats. This can help promote genetic diversity and overall resilience in local ecosystems in our residential communities.
#4. Outdoor Classrooms and Community Projects
Incorporating native plants and natural features into urban and suburban creates attractive green spaces that provide a sense of calm and relaxation in otherwise hectic environments. These spaces serve the dual purpose of outdoor classrooms and projects for engaging the community.
This makes parks, churches, and school grounds ideal candidates for rain gardens. These present opportunities for local businesses to sponsor the construction and maintenance of these projects, providing necessary resources, such as labor, equipment, expertise, and funding. Benefactors can be recognized for their contributions, and future enhancements are added, such as benches, walkways, and outdoor lighting.
#5. Rain Garden Maintenance and Upgrades
Rain gardens require regular maintenance to ensure they function properly and continue to provide benefits over time. In the spring, it’s important to remove debris such as leaves and twigs from the garden, prune plants to prevent overgrowth and monitor soil moisture levels to ensure the garden is properly draining and not becoming waterlogged.
Throughout the summer, monitor soil moisture levels and water the garden as needed, especially during periods of drought. In the fall, it’s important to remove any fallen leaves and cut back plants that may become too woody or overgrown.
In addition to regular maintenance, rain gardens may require troubleshooting to address common issues such as poor drainage or plant disease. In cases where the garden is not draining properly, it may be necessary to dig out the soil and amend it with additional sand and organic matter. If plant diseases are detected, affected plants should be removed and disposed of properly to prevent further spread.
By following a regular maintenance schedule and addressing any issues promptly, homeowners and communities can ensure that their rain gardens continue to provide effective stormwater management and other benefits for years to come.
Proactive Landscaping: Helping Oklahoma Homeowners Enjoy Outdoor Living
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