What They Are and How To Use Them
Rain gardens are gardens specifically designed to absorb rainwater run off. They are used successfully to catch water from roof downspouts, parking lots, turf and other surfaces. They typically are designed with some type of depression that allows for water to collect and disperse into the soil. In order to be successful, rain gardens need to be sized correctly for the amount of rainfall it will be absorbing and have a plant palette that will ensure successful drainage and withstand the presence of temporary pooling water.
Rain Garden Profile
Here's an instance where a rain garden was an appropriate solution:
Learn more about this rain garden project here.
Why Have a Rain Garden?
Rain gardens can solve rainwater runoff issues.
Rain Gardens are unique beautiful landscape features.
The unique growing conditions created by a rain gardens allow the use of plants that you may not have had the ability to grow. For instance plants that enjoy living in temporary wet conditions that would otherwise not work in your yard work in a rain garden.
Rain Gardens attract beneficial wildlife.
We use a native centric plant palette in our rain gardens. Native plants are adapted to handle the unique demands of growing in a rain garden. The use of natives creates a habitat which attract beneficial insects that can help keep your insect pressure down in your gardens. That’s a win.
Rain Gardens improve our community's water quality.
You are becoming the change you want to see. Chances are you don’t like the idea of raw sewage flowing freely in your creeks and rivers. By having a rain garden you are directly contributing to alleviating our regions combined sewer overflow problem. Thank you in advance.
So, you have a rain water problem and now you see there are some benefits to going the rain garden route. But, they are not a ‘one size fits all’ solution when it comes to solving rain water issues in the yard. First lets go over when they are a good solution.
Locating Your Rain Garden: The Do’s + Don’ts
Understanding when rain gardens are a good solution is the key to a long term successful garden and alleviates the potential issues of a failed rain garden. It can happen!
A large contributor to success is locating a rain garden properly. You should consider the following:
Proximity to structures - you want to make sure your rain garden is at least 10’-15’ away from a structure with a basement and also down slope from the structure.
Proximity to existing trees - Do not locate rain gardens close to existing tree root systems or existing gardens as the soil disturbance required for a rain garden could cause serious damage.
Proximity to septic systems - 50’ is the minimum distance you want to locate a rain garden from a septic system as the infiltrated rain water could overwhelm the system.
Slopes - Cincinnati is a hilly region with different grades of slope. You want to make sure that the slope of where you are thinking about installing rain garden will be under 12%. Beyond that you will begin to run into slope stabilization issues that can be complex.
Space for Overflow - ideally your rain garden should be located where if the rain garden fills up during a particularly heavy rain the water can overflow to an area that can handle it. Areas like a creek, street curb, or sewer. This is your all important backup, plan B.
Soil - If you live in the Cincinnati Metro Region you probably have a clay based soil. You want to make sure where you are building the rain garden will have a infiltration rate of ‘1/2”-1” per hour’. Learn how to test your infiltration rate here. If you don’t have the desired infiltration rate with your current soil, you can usually amend compost into the rain garden to achieve this.
If you have made it through this checklist and still have potential areas where a rain garden will work. Congrats! If not, there are definitely other green infrastructure options for your yard. See a list of them here.
My next post will be about how to determine the size of your rain garden.
The Mosquito Fallacy
When talking to clients about rain gardens I often get the question about whether rain gardens will be a mosquito magnet for the yard. Thankfully they are not. Rain gardens are designed to drain rain water within 24 hours if not within an hour or two. They are not wetlands. This amount of time does not allow mosquitos to complete their larvae 7-12 day life cycle. Along with this your rain garden will more than likely be attracting insects and or birds that like to eat mosquitoes.
Interested in a rain garden, but are still unsure? We offer consult, design and installation services and would be happy to learn more about your project. Click HERE.