DIY Rain Garden

How to Reduce Stormwater Runoff in Your Own Backyard

Stormwater runoff is a serious environmental issue that affects our local waterways and ecosystems. But, did you know that you can make a difference in your own backyard? Let us introduce you to rain gardens - a simple yet effective landscaping feature designed to capture and filter rainwater, reducing the amount of stormwater runoff that enters our local waterways. In this article, we'll take you through the steps of creating your own rain garden, so you can play a role in reducing the negative effects of stormwater runoff on the environment.

How a Rain Garden Works

Rain gardens are designed to capture and filter rainwater, making them a powerful tool in the fight against stormwater runoff. By providing a place for water to soak into the ground, rain gardens help to reduce the amount of water that flows into local waterways, which can be particularly harmful during heavy rain events.

Stormwater runoff can be a major contributor to water pollution, carrying pollutants from our roads and hard surfaces into streams and rivers. By capturing and filtering rainwater, rain gardens help to minimize the negative impact of stormwater runoff on the environment and keep our waterways clean and healthy.

Designing Your Rain Garden

Rain Garden in your yard

Determine the Best Location for Your Rain Garden

The first step in designing a rain garden is to determine the best location for it. Look for a low-lying area in your yard where rainwater naturally flows or pools. This will ensure that your rain garden will be able to capture the maximum amount of water during a storm. It's also important to choose a location that is at least 10 feet away from your house to prevent water from seeping into your basement.

Consider the Size of Your Rain Garden

The size of your rain garden will depend on the amount of rainfall your area receives, the size of your property, and the slope of your yard. As a general rule of thumb, a rain garden should be at least 100 square feet, but larger is always better. A larger rain garden will be able to capture more water and will be more effective at reducing stormwater runoff.

Choose Appropriate Plants for Your Rain Garden

Choosing the right plants is crucial for the success of your rain garden. Native plants are a great choice as they are adapted to the local climate and soil conditions, and they also attract beneficial wildlife to your garden which supports local biodiversity.

When selecting plants, consider their water needs, as well as their size and color. It's also a good idea to include a mix of plants with varying root depths to ensure that water is absorbed throughout the soil profile.

Recommended plants
  • Redbud (cercis canadensis)
  • Beautyberry (callicarpa americana)
  • Virginia Sweetspire (itea virginica)
  • Inkberry (ilex glabra)
  • Blue Flag Iris (iris virginica)
  • Black Eyed Susan (rudbeckia fulgida)
  • Switch Grass (panicum virgatum)

Make Sure Your Rain Garden Has Proper Drainage

Proper drainage is crucial to the success of your rain garden, as it ensures that water is able to flow freely and be filtered by the plants and soil. Before you start digging, make sure to check the drainage of your chosen location by observing how water flows through the area during and after rainfall. . Without proper drainage, your rain garden may become waterlogged, which can lead to plant stress, disease, and even death. To prevent this, make sure that your rain garden is sloped correctly and has well-draining soil. You may also need to add a layer of sand or gravel to improve drainage.

Building Your Rain Garden

Rain Garden Diagram, Reduce the Impact of Stormwater

Image © The City of Calgary

Mark and Excavate Your Rain Garden

Once you have chosen the right location, you can use stakes and string or spray paint to outline the shape of your garden. This will give you a clear idea of how much space you have to work with and help you plan the design of your garden. Then, use a shovel to excavate the soil to a depth of about 6-8 inches or as much as 1-2 feet for areas with high clay content. This depth is important because it will provide enough space for the garden to collect water without becoming flooded. It's important to save the soil you remove from the excavation, as it will be needed later to amend the soil in your rain garden.

Ensure you include a berm to help direct water flow into the garden and prevent it from overflowing into unwanted areas. Essentially, the berm is a small mound of soil that is built up along the outer edge of the garden. It can be as simple as piling up the excess soil from the excavation process or more intentionally designed to create a gentle slope towards the center of the garden.

Amend Your Soil

Rain gardens require soil that can absorb water quickly, so it's important to amend your soil with compost or other organic matter. Before you begin amending your soil, it's important to test it to see what type of soil you have. Different soil types will require different amendments to help it absorb water. You can purchase a soil test kit from a local garden center or get a soil test done through your local extension office. 

Clay soil can present a challenge when building a rain garden because it tends to be compacted and poorly drained, which can impede the flow of water and hinder plant growth. A good rule of thumb is to aim for a mixture of about 50-60% sand, 20-30% topsoil, and 20-30% compost with no more than 10% clay.

Amending the soil is a crucial step in creating a successful rain garden, as it can help to improve drainage, plant growth, and overall garden health. With the right amendments, even clay soil can be transformed into a thriving rain garden.

Plant Your Garden

When planting, arrange the plants in a way that mimics their natural growth patterns, with taller plants in the center and shorter plants around the edges. This will help create a natural-looking garden that is visually appealing. Be sure to plant the flowers, grasses, and other plants close enough together to create a dense network of roots, which will help absorb excess water and reduce erosion.

Add Mulch

Once your plants are in place, add a layer of mulch on top. Adding mulch is an important step to help keep your rain garden healthy and thriving. In addition to preventing soil erosion and controlling weeds, mulch helps to retain moisture in the soil and regulate soil temperature. This is especially important during dry periods or heat waves.

Natural mulches like wood chips or pine bark are great options as they add nutrients to the soil as they decompose and won’t wash away. Avoid using synthetic mulches like rubber or plastic as they can release harmful chemicals into the soil and disrupt the natural ecosystem of your garden.

Maintain Your Rain Garden

Finally, you will need to water and maintain your rain garden. Watering will be necessary during the first few weeks after planting to help establish the plants, but after that, your garden should be able to thrive on natural rainfall. Be sure to keep an eye on your garden and remove any dead foliage or weeds to keep it healthy and beautiful.

Small Steps, Big Impact

With our communities growing and developing rapidly, it's essential to take action and minimize the harmful effects of stormwater runoff. The good news is that designing and building a rain garden is a simple and effective way to make a positive impact on your local ecosystem. It's a fun and rewarding project that can benefit not just your home, but your entire community.

By following the steps outlined in this guide, you can create a beautiful and sustainable landscape that helps reduce stormwater runoff, protect local waterways, and promote biodiversity. So why wait? Take action today and start building your very own rain garden. Your community and the environment will thank you for it.

Building a Sustainable Community Starts Here

Want to learn more about how you can make a difference in your community and support the environment? Join our newsletter and take a look around our website to find out about upcoming events, volunteer opportunities, and resources that can help you live more sustainably. Together, we can make a positive impact on our local ecosystem.