A few weeks ago, we had an unexpected monsoon.
The storm blew through during the night, with thunder and lightning accompanied by a long, heavy deluge. Flash flood warnings dinged my cellphone and were broadcast by local weather forecasters.
In the morning, while walking the dogs in my garden, I noticed the “dry stream” there had 2 inches of water flowing through it, and a previously empty basin contained nearly 6 inches of fresh, clear rainwater. Farther down the hill, deep rivulets had cut through the mulch and washed serious gouges in the gravel trail. Despite recent drainage improvements on my part, damages to the landscape were significant.
Stormwater management is becoming more important for our landscapes as climate change alters local rainfall patterns. We are experiencing more intense storms with short but heavy rainfall. So prepare your garden for the future by creatively addressing water flow now.
Preventing erosion and managing mosquitos constitute short-term local benefits, but excellence in runoff management affects stream biodiversity and downstream water quality, and can help reduce flash floods.
In that regard, the next time a heavy rain falls, put on your waders and grab an umbrella. Walk your property to see where the water’s going. Do you have overflowing gutters, puddles of standing water, sheets cascading off your driveway or streams inundating your downhill neighbor? Rainwater management primarily seeks to slow such water down, get it to soak into the ground, capture it when possible and keep as much as you can on your own property.
Otherwise, consider these steps for stormwater management:
- Inspect your property after every major storm for erosion, and repair the damage quickly to prevent increasing damage.
- Replace downspouts with Japanese rain chains, where appropriate, to slow the flow rate of rooftop water.
- Add decorative pebble aprons to downspout outfalls to slow runoff and prevent washing.
- Use rain barrels to collect and store fresh rainwater.
- Create dry streams with rock weirs or bio-swales to direct and slow storm runoff.
- Reduce compacted lawn areas, and replace them with moisture-absorbing mulched beds.
- Plant more trees and shrubs, which make great natural filters.
- Add a rain garden to slow and filter flow and add seasonal color.
- Make any new paving projects with water-permeable materials.
Karla Wilson – manager of the Deer Creek Watershed Alliance, a cooperative program based at the Missouri Botanical Garden with dozens of partners, including Ladue – says that although large rain events like this recent inundation are best addressed by good public policy and planning, the actions of all property owners make a difference.
“Every drop of rain that goes into the ground instead of running off will improve the health of the entire watershed,” Wilson says. In addition to basic rainscaping, she strongly recommends removal of invasive bush honeysuckle now to prevent future soil erosion.
To learn more about rain gardens and community watershed management, email the Deer Creek Watershed Alliance at email@example.com, or read “Rainscaping Guide” in the Water Quality subsection of the Sustainable Living at Home section of the Missouri Botanical Garden’s website, at mobot.org/rainscaping.