Urban areas cover only 3% of Missouri, but ecosystem impairment is present in 13% of rivers, 18% of lakes, and 32 estuaries throughout the state. Impervious surfaces such as rooftops and driveways have replaced healthy soils and natural plant communities that once readily absorbed rainwater. The resulting runoff contributes to water pollution, health challenges and property damage.
One way that the average homeowner can work to address those problems is by creating a rain garden in his or her own backyard.
Rain gardens are depressed areas landscaped with perennial flowers and native vegetation that soak up rainwater, filtering pollutants, reducing stream bank erosion, decreasing runoff, and lowering the water volume entering the storm system.
Rain Garden Location and Size
To choose the location of the planned rain garden, first observe how water flows on the property. Consider areas seem particularly erosion-prone and those that are at the end of sloping areas of lawn.
Make sure not to select any area that is under trees or any area that is within 10 ft of the house’s foundation. Any water that gathers there must drain in 24-48 hours and the slope cannot be greater than 12 percent.
A rain garden typically takes up 25-35 percent of the total drainage area. Its basin’s depth depends on the slope of the land it is on.
- 4% slope or less = 3-5 inches deep
- 5-7% slope = 6-7 inches deep
- 8-12% slope = 8 inches deep
To figure out the recommendations for your plot of land, you can use the size estimator provided by showmeraingardens.org.
Rain Garden Plant Options
It is recommended to use the “right plant, right place” approach when creating a garden. Don’t fight against the soil and moisture level, instead work with them; this will make maintenance much easier in the long-run.
Three different soil types are possible and can be easily tested for prior to plant selection.
- Sandy soil = drains quickly, holds little water or nutrients
- Loamy soil = retains moisture and nutrients, allows water to flow freely
- Clay soil = rich in minerals, compact and acts as a barrier to water drainage
The moisture level in and around a rain garden basin will range from moist to dry on any given day, so plants should be chosen for moist to average soils and for average to dry soils.
It is strongly recommended to go with regionally native plants that fit inside the specifications listed above.
Regionally native plants are adapted to the local climate and soils, as well as the annual fluctuations in rainfall. They therefore need minimal irrigation, and pesticide and fertilizer use can possibly be eliminated altogether. They are also more apt to grow deep root systems, which aids in minimizing erosion.
Morgan Niezing
Digital Media Intern