Rain gardens offer a low tech solution for excess rain water

Question: The rain barrel I installed this summer seems very small in view of the large quantities of rain we have gotten. What other strategies can I use to reduce the water runoff from my property?

Answer: Rain barrels or cisterns have their place in water management, but as you have seen they are totally inadequate alone to deal with large amounts of rainfall. There are several ways to deal with excess rain, but clearly the way we do it now in urban areas does not work very well. We have large areas of impervious surfaces and we direct water into storm water systems that often become overwhelmed. What if every home, apartment complex, business or neighborhood could capture the first inch or so of rainfall in any rain event? I believe this could be done and would go a long way towards reducing storm water and associated non-point source pollution problems.

Rain gardens are an old idea whose time has come again. Let’s face facts. We in the southeast live in a climate where we always have and always will have a feast or famine of rainfall. Even those with a short term memory can recall the severe drought of 2007. However, those of us with better memories and a few years behind us knew the day would come when flooding would be a problem again. Rain gardens offer a low tech and low cost way of slowing down water, letting it infiltrate rather than contribute to the storm water problem and reducing the amount of non-point pollution that enters our streams and rivers.

Simply speaking a rain garden is a depression or swale in the landscape designed to capture and retain runoff for short periods of time. If designed properly rain gardens should drain in three days or less and provide a way to direct overflow in periods of continual rainfall such as we have recently experienced in much of the southeast. Rain gardens can and should be a landscape asset both in terms of function and beauty. Ideally they should be located several feet away from the home to avoid contributing to water related problems in the basement or foundation. Water that currently runs off the house, walks, parking areas and driveways should be diverted to these depressions to slowly soak into the ground.

Do not think of a rain garden as a pond that does not hold water very well. Think of it as a true garden in every sense of the word. It is not a landscape feature but a critical component of the functionality and beauty of the landscape. Choose plants that can tolerate both occasional flooding and fairly extreme drought. Fortunately, we have many southeast natives that fit the bill very well because many of them have had a feast or famine relationship with water for a very long time. Because of this long standing weather pattern many native plants have become adapted to these environmental conditions. However, not all native plants will thrive in these conditions so you must do a little research before choosing your plants. Native plants fill niches within our environment so look for those plants that naturally grow in the light and soil conditions you have or will create within a rain garden. Do not forget about the many tried and true non-native plants that also grow well under these conditions.

Many books are available to help you make the right plant choices but for a more comprehensive look at this topic I strongly recommend Rain Gardening in the South, by Helen Kraus and Anne Spafford. As the name implies this book focuses on strategies as well as plants that work for southern conditions. The plant lists are great even though there are many plants that would work that are not included and a plant or two I would avoid that are included, such as Japanese Flowering Apricot. However, the information on design is well worth the modest cost of this book. Even though rain gardens are low tech they are not simple given that they are a small ecosystem unto themselves. Therefore, careful attention to design is important to make certain it functions as intended. For instance, you do not want to build a mosquito haven and this must be addressed early to avoid costly “do over’s”.

Fall is an excellent time to build a rain garden and an even better time to establish trees, shrubs and many perennials that may be used. It won’t rain forever, so start working on your plans and when it dries out get your shovel and go to work. Don’t forget to call before you dig to avoid costly and potentially dangerous encounters with underground utilities. For help locating buried utilities contact “Alabama One Call”. For further information on building your own rain garden visit the Alabama Cooperative Extension System web site and type in rain garden in the search box at the top.

Image by North Carolina State University