Protecting Shoreline

Wetland vegetation reduces erosion along lakes and stream banks by reducing the force of waves and currents.

Location of Shoreline Wetlands

Only wetlands that lie at the fringe of lakes and within creeks, streams, rivers, and other watercourses can protect shoreline.

The wetland portion is typically the area that is less than 6.6 feet deep. Also included as shoreline wetlands are floodplain/riverine systems (i.e. wetlands present between the active river channel and river banks that may experience frequent water level fluctuations and/or erosive forces).

Rooted Shoreline Vegetation

The erosive strength of waves and currents can be greatly dissipated by a dense vegetation cover including submerged aquatic plants. The greater the vegetation density, the greater the shoreline protection.

Wetland Width

Wetlands with wide stands of vegetation are more likely to stabilize sediments than those with narrow stands. Research shows wetlands wider than 30 feet reduced wave energy by 88% while emergent wetlands less than 6 feet wide were relatively ineffective in wave buffering. Measure width starting from the deepwater edge up to the normal water‘s edge, not to include the shore area up out of the water itself.

Shoreline Erosion Potential

Wetlands located in areas with strong currents and wave actions have the greatest potential for protecting shoreline. Shorelines composed of sandy or erodible soils will benefit the most from shoreline wetland protection.

Bank Protection Ability

The potential for erosion and/or slope failure of shoreline or streambank areas is also dependent on the land use and condition on the slope above the water level and on top of the bank. Bare soils or those with shallow rooted grasses that are manicured on a regular basis provide less protection than deep-rooted grasses allowed to grow naturally.

Source: Minnesota Routine Assessment Method (MnRAM), Version 3.4, Minnesota Board of Water and Soil Resources