Science

Treat Stormwater by Becoming a Lake Wise Gardener

It’s true that “April showers bring May flowers,” but unless your shoreland is well armored with native plantings, rains can cause erosive runoff and destabilize banks, bringing sediment and nutrients to the lake.  This spring, during a rain event, venture outside and follow the flow on your property to learn the sources of stormwater runoff.  Then, as you prepare to plant this season, you will be able to nurture beautiful native species as well as site them to soak up the flow, protecting lake water quality.

stormwater Bomoseen

Stormwater runoff from cleared shores causes turbid waters to Lake Bomoseen. April 2017, Castleton

Stormwater occurs when rain and snow melt events run off the land instead of being absorbed by it.  Impervious surfaces, such as roofs, decks, and driveways shed water and cause stormwater flow.  Lawns, especially on sloped shores, also contribute to stormwater as they only soak up a little runoff. By observing a storm event on your shore, you can identify both the sources and solutions for treating the stormwater, and keep it from polluting the lake.

Wisconsin studies have shown that developed shores contribute five times more runoff, seven times more phosphorus (the nutrient that feeds aquatic plants and algae) and 18 times more sediment to the lake than undeveloped shores.  Cleared shores not only lead to nutrient loading, but also break the interface between lake and shore, disrupting the lake ecosystem. Removing native shoreland vegetation decreases shade and increases water temperatures; undermines bank stability with the loss of root structure to hold a bank together; removes the duff layer, which is the spongy decomposing leaf and twig litter that protects the lake by absorbing and treating runoff; and diminishes critical wildlife habitat.

sediment plume

Sediment plume from shoreland erosion. April 2011, South Hero

The Lake Wise Program offers solutions for managing stormwater. Some of these shoreland Best Management Practices are structural, like using driveway waterbars to slow and direct runoff to a side treatment area; or infiltration stairs to prevent pathway erosion.  However, most shoreland BMPs use vegetation, such as raingardens, swales, berms, and shoreland buffers.  Re-establishing native plant species will absorb and treat stormwater and provide essential wildlife habitat.

chickadee

A Carolina chickadee needs more than 5000 insects to produce one clutch of hatchlings.

Each black cherry tree, Prunus serotina, plays host to over 450 insects, an oak, Quercus spp., over 530, a birch, Betula spp., more than 400, and so forth for native trees, shrubs and herbaceous plants playing host to native insects.  Native host plants are critical for feeding birds and provide up to 40% of protein (insects dropped from overhanging branches) for fresh water fish. Doug Tallamy, Entomologist from the University of Delaware, teaches how native insects co-evolved with their native host plant and that they can’t survive on nonnative plants because they can’t break down their chemical defenses. Tallamy says “Caterpillars, a particularly important food source for birds, are especially picky about what they feed on.  Like the famous monarch butterfly larva, which must have milkweed to survive, more than 90 percent of moth and butterfly caterpillars eat only particular native plants or groups of plants.”  Basically, no native plants, no native insects, no food for birds and fish and one sterile lakeshore.  But that’s not all, as the lack of shoreland vegetation allows stormwater to enter a lake untreated, which degrades water quality and can cause decreased property values.

native stabilization

Native plantings stabilize the bank, soak up and filter stormwater, while providing essential wildlife habitat. This is a 2015 Federation of Vermont Lakes and Ponds (FOVLAP) planting project on Harvey’s Lake, Barnet.

As you enjoy all the familiar signs of spring this year, consider ways to manage the stormwater on your property by minimizing your lawn and revegetating areas with native plants to soak up and filter the rains and to welcome back the birds and the bees.  For suggestions on stormwater BMPs and native plantings or to learn how to participate in the Lake Wise Program, visit the Vermont Lake Wise web site or contact Amy Picotte at Amy.Picotte@Vermont.gov

The Lake Wise Program is a Vermont Agency of Natural Resources initiative that supports and awards lake-friendly shoreland property.