The best landscape design near a body of water is one that prevents surface water runoff from entering directly into the lake, pond or stream. Existing trees, shrubs, and ground covers can trap runoff water from rain and snowmelt and allow it to settle into the soil where it can replenish groundwater.
Runoff from rain contains nutrient-laden silt. One of these nutrients, phosphorus, feeds algae in the water; algae “blooms” can kill fish, turn the water green, and create an awful odor. Nutrient-laden silt carried into the lake settles on the bottom creating a fertile bed for unwanted weed growth. Sediment can fill stream beds, inhibit water flow, damage fish spawning areas, and suffocate organisms living on the bottom.
Keep a Green Buffer Zone
State and local regulations require a buffer zone of native vegetation to be retained in an area near the shore in order to limit run-off. (See your town’s regulations and New Hampshire’s Shoreland Water Quality Protection Act.) Plantings, including trees, shrubs, grass (best when left uncut), and other herbaceous plants trap silt and slow the flow of run-off. Plant roots hold the soil together, reducing the chance of erosion, and absorb nutrients from runoff water.
It is also important to allow natural materials such as pine needles, leaves, and small branches to build upon the soil as they do in the woods to create a “duff” layer. This organic layer adds nutrients to the soil and slows the flow of surface water.
Minimize the Area of Lawn
Plants trap runoff better than manicured lawns. Ground covers and rock gardens can be a sensible alternative to grass. Careful pruning can maintain the views over shrubs. Any lawn should be minimal and as far away from the lake as possible with a good buffer zone of shrubs and trees. Lawns grown with native and naturalized grass species will require less care and need little, if any, fertilizer.
Grade for Erosion Control
Grading surfaces flatten small irregularities that naturally exist on the surface of the land. These depressions are beneficial in their ability to trap and store water, allowing it to seep down into the soil. Include depressions in your landscape planning. Plan drainage and grading so that water flows away from the shore and can settle naturally. Be sure runoff from surfaces such as driveways and roofs has the opportunity to settle into the soil of vegetated areas. Steep slopes need dense vegetation cover to control erosion.
Design Paths and Walks to Meander
Allow any path leading down to the shore to curve and meander, so that water will not travel down the path, but settle into the soil along the way. Walks should be made of permeable materials to help water settle into the soil, rather than run into the lake. Consider alternatives to pavement for driveways to increase infiltration.
Plant with Native Species
Plant species occurring naturally in this area of New Hampshire will most likely thrive, be less expensive, and require the least amount of care. Landscaping of a lakeshore property needs special consideration so that the lake is minimally harmed by human contact. Ground covers, shrubs, and trees serve an important function in trapping sediment and water runoff. This pamphlet explains why lakes need a green buffer area and suggests landscaping considerations for both established and new properties. Included are lists of both native and appropriate non-native species for different soil and light considerations
The Wentworth Watershed Association gratefully acknowledges the use of materials from the Lake Sunapee Protective Association in the preparation of this publication. Lake Sunapee area landscape design professionals Sue Clough and Nancy Fleming contributed to this pamphlet. Wendy Ward assisted in identifying invasive shoreland species.