Lake Life Today: Best Management Practices (BMPs)
Berms are vegetated mounds of earth with gradual sloping sides that “slow the flow” and soak up stormwater runoff. They run parallel to the shoreline with a 4:1 ratio (meaning that for every vertical foot, there will be four horizontal feet to create the proper slope). Berms are usually built on top of the existing “duff” (the accumulation of leaves, pine needles, etc., that have dropped below the trees). Depending on the area where a berm is located, or the height of the berm which is needed, some minimal groundwork may be required.
Here are the directions on how to build a simple berm:
Lay a bed of large stones to form the berm’s foundation.
Cover the stones with soil.
Cover the berm with mulch and pine needles.
Stormwater flowing beyond a berm should be directed into dense, permanent vegetated areas capable of absorbing the stormwater.
Adding plants to a berm increases its effectiveness. The best plants to use are native plants, including grasses and shrubs. The goal is to cover the entire berm with vegetation.
Note: Any project involving more than minor soil disturbance within 75 feet of the water requires a permit from the Maine Department of Environmental Protection (DEP). Local municipal permits may also be required depending on the distance from the water, and these distances may vary by municipality.
For more information on how to install a berm go to: http://dec.vermont.gov/.../LakeWiseInfoSheet_FilterBerms.pdf
Also, a helpful site to find native plants can be found at Maine Audubon: https://mainenativeplants.org/
Reprinted with permission from Elaine Philbrook, LakeSmart Director for CRLA. Sources: Maine Lakes, Lakes Environmental Association (LEA)