Safe Water and Native Gardening

Rolf Cachat-Schilling, Horticulturalist/Plant Records Coordinator

(Installment 1 of 3)

This spring saw the Society’s first green roof come into bloom. Located in our Idea Garden, the Native Plant Green Roof adorns an old wooden shed with tough plants from the Northeast United States on the north side and Southeastern plants on the south side. True to their nature, our native plantings are thriving and blooming freely in their new rooftop environment.

Toxic stormwater runoff

Aside from being far more attractive than asphalt, many gardeners already know that green roofs lower heating and cooling costs. But many do not know that green roofs and alternatives to impermeable pavement have an enormous impact on safe drinking water. A shortage of clean drinking water resources is a major issue for many municipalities and homeowners.

The greatest source of drinking water contamination, according to the EPA, is stormwater runoff. Summer thunderstorms washing over your hot asphalt roof collect toxic compounds and decomposition by-products. That tainted water travels across paved drives and roads, picking up toxins from oil, antifreeze, and gasoline additives (some of which are among the most dangerous chemicals in our environment). Much of that water makes its way through storm drains and local streams into drinking water. Far-flung locations may share a common water table, where stormwater toxins settle and concentrate.

Reducing runoff, safer water

Green roofs vastly reduce runoff from rain, reduce accumulation of toxins, and can even reduce impact of acid rain. Combined with energy savings from reduced cooling and heating, green roofs offer a bounty of benefits in addition to their beauty. Many green roofs are large-scale projects—schools, municipal offices, shopping malls—but you can also have a simple green roof on your home, or even create your own for a garage, a house addition, or a shed.

You can have a positive impact on the quality of your drinking water by installing green roofs at your home and reducing impermeable paved areas. You can also encourage your municipality and your employer to save on energy and protect water resources by including green roofs and permeable pavements in their plans to go green.

You wouldn’t be the first: The city of Chicago has green-roofed many of its buildings, modelling their program after Stuttgart, Germany, which legislated green roofs into a city standard years ago. Both cities have recovered their costs in savings and continue to reap the benefits and spread the message. Everyone from firefighters in Montana to suburban homeowners in Illinois are saving and protecting water quality by installing green roofs.

Stay tuned for tips on designing a do-it-yourself green roof and selecting native plants for green roofs.