Rain Gardens: How to Deal with Drainage
Have you ever looked at your home and realized that water is collecting in various hot-spots after a storm? Stormwater management and drainage is a common issue in both urban and suburban environments! This issue is typically caused by improper grading, and the excessive seasonal rainfall can lead to flooding, erosion, and soggy yards. Lucky for us, Mother Nature already knows how to handle this excess water! By working with the rain rather than against it, we’re able to easily manage drainage and storage. We can do this with something called Rain Gardens! Rain gardens utilize the natural systems of drainage to manage the excess storm water and direct it to the soil where it can be safely drained with little issue.
A natural rain garden in a public park, courtesy of Alisha Goldstein.
Natural Rain Gardens
When designing a rain garden, we look at our natural ecosystems for inspiration! Natural flood-planes are formed alongside rivers, streams, and seasonal springs. These areas flood often, for extended periods, but remain dry most of the year. The plants that live in these ecosystems are wired to adapt, tolerating both excessive flooding and extreme drought. They also support various wildlife species including frogs, salamanders, and newts - all of which rely on the seasonal pools in the planes. They actually need this fluctuating ecosystem to safely lay their eggs away from fully-aquatic predators!
For natural rain gardens, look to your local ecosystem for ideas! In areas where rainfall is commonplace, your plants will need to adapt the same way the flood-plane plants do, and the soil will need to be supplemented to provide ample drainage. In places that get heavy seasonal rains, these plants can look like deep-rooted perennials! They can tolerate extended periods of drought and are effective when used to aerate even the most dense of clay soils. Because these gardens are so weather dependent, they will need to be adapted to your unique location and carefully planned - but the drainage results speak for themselves!
When Rain Gardens are Essential
While rain gardens can typically benefit everyone, they are especially useful in areas with poor drainage or high erosion. Rain gardens are designed to slow down and direct the water flow. With a close look, you may even notice these in parks, cities, and suburbs! You might even see it and not notice - most cities and suburbs direct stormwater away from populated areas and into a central pond. That’s an attempt at a rain garden! While this system can work, it often leads to more intense flooding, just father away from the people. Improper grading or eventual degradation due to erosion will eventually cause the water to pool in yards, parking lots, and roads. Fully-incorporated and planned rain gardens can supplement the existing system efficiency while greatly reducing residential flood risk.
On the residential scale, rain gardens can be extremely beneficial in suburban lawns. Typical turf grasses don't actually have deep enough roots to aerate the heavy clay soils found across most of the southeastern US. Because of this, our rainwater pools in our yards will eventually lead to unsightly bare and muddy patches. By strategically placing rain gardens to catch and direct incoming water, we can mitigate this damage while providing ourselves a beautiful garden space - even benefitting local wildlife!
How to Build a Rain Garden
When creating a rain garden, it is important to consider the layout of the garden first. To start, you will need a shallow reservoir filled with compost-amended soil to help absorb and hold water. This reservoir should contain plants that are both drought and flood tolerant. They will often consist of native grasses or perennials that can handle short bouts of flooding. Their deep roots will help aerate the soil, helping it absorb more water! On the sides of your reservoir, it is important to densely plant your perennials. This will hold the soil in place. Then, plants that form dense clumps and cover are perfect for slowing down the water and protecting the sides of your reservoir from eroding! With the area around your garden planted and graded in a way that pushes water towards the reservoir, you’ll have a wonderful start to your stormwater management! To push the water even more efficiently, you can plant dense perennials, or implement a false river bed or swell!
By embracing the beauty and resilience of natural systems, rain gardens can enhance the functionality of your outdoor space, all while helping to create sustainable ecosystems for wildlife. If you want to learn more about how a rain garden might help your property, contact us today!
