Earthworms’ Castings

by Jean Ponzi

The Answer is Growin’ in the Rain

This time of year especially, we see the havoc rain can play – in our streets, basements, storm sewers, swollen rivers.

We’re blessed with plenty of water in our part of the world, but the ways we manage this precious resource need a flood of sensible changes to protect the water itself, and our precious human environs.

We can get the kind of help we need – from plants! Plant roots hold and help purify water. They stabilize soil and prevent washouts. Plus the vital “ecosystem services” provided by plants can be subtly or spectacularly beautiful while amazingly functional. It all grows together in Rain Gardens.
A rain garden is a specifically constructed and planted landscape feature designed to capture and hold the water that otherwise rapidly runs off building roofs and hard ground surfaces during a storm. Water retained in this kind of intentional, temporary pond will percolate down into the ground over a couple of days after rainfall, helping to recharge the groundwater supply, called aquifers. Pollutants are filtered out as storm water passes through plant root systems, so clean water eventually returns to the streams and rivers that provide the water we drink and depend upon in so many ways.

Even though it drains slowly, rain garden water won’t become a hazard to human health. The water is detained aboveground for too short a time to let mosquitoes, which need standing water to breed, complete their larval stages and hatch into biting adults. But enough aquatic elements remain in a rain garden to attract beneficial insects, birds and even amphibians like frogs or turtles.
A simple rain garden can be built near a building downspout, which gets extended to drain into the planted basin. Or a home or commercial property landscape can be graded so that water drains off all walking, parking and driving surfaces – and building roofs – into these versatile planting beds. It’s possible, with proper planning and installation, for a rain garden to detain almost all the water that would otherwise run off “hardscape” areas. Skillfully integrated with other property features, a rain garden can significantly reduce, or even eliminate, municipal sewer and water treatment systems.

Plants are the best part of a rain garden’s powerful capabilities. Species that thrive in a rain garden can go from drought to flood conditions without missing one green beat. These exceptional adaptations are fascinating to experience in planting and observe over time.

Around the St. Louis region, rain gardens are a relatively new trend in sustainable site management. It’s helpful to see and learn about them first-hand – and a terrific opportunity is coming this month!
On Saturday, May 15, the Deer Creek Watershed Alliance will host a free Rain Garden Block Party, in and around Oakbrook Park in University City. Six households in this neighborhood planted rain gardens last fall, as part of a regional effort to study and improve water quality in Deer Creek and its suburban St. Louis tributaries. Master Gardeners will guide tours of these gardens from noon to 3 p.m. and Deer Creek allies the Missouri Department of Conservation, Missouri Botanical Garden, U City in Bloom, Metropolitan Sewer District and other groups will be on hand with native plant and other giveaways, free bar-b-cue, and activities for the whole family.
Visit www.deercreekalliance for event details, and to learn more about local water protection efforts and options.

When it rains, this beautiful stuff can grow on you!
Jean Ponzi hosts the enviro-talk show Earthworms on FM-88 KDHX. Listen live Mondays, 7-8 p.m. or catch an archived edition at www.kdhx.org.

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