Coastal Erosion Home	View Maps & Coastal Shoreline	Setback Calculator	Coastal Erosion Resources

Stable Slope Setback (SSS)

Slopes reach a stable slope angle if they are not undercut by waves or otherwise disturbed for many years.  Even if all shore erosion were to cease, bluffs continue to recede as they adjust to this stable slope angle. The Stable Slope Setback (SSS) is the distance between the present position of the bluff top and the position where the bluff top would be at a stable angle.  Even if the toe of the slope is being protected from wave erosion, this component of set back is necessary to ensure building safety.

Stable angles vary

Different bluffs stabilize at different angles. The stable slope angle depends of the type of soil or rock material in the bluff. Material types have been mapped and translated into a stable slope angle for all of western Bayfield County.

Here are some examples:

Determining the SSS

To determine the SSS we start by measuring the current slope angle. The SSS is the distance from the position of the current bluff top at the measured slope angle to the bluff top position for the stable slope angle.

In the example below, the current slope angle is 25 degrees. This bluff is composed primarily of clay till. Therefore, the stable angle is determined to be 14 degrees. The SSS is 93 feet because the bluff top will need to recede at least 93 feet to reach that stable angle.

For more information contact: