Shoreline Stabilization

Stabilization protects shoreline from erosion.

How does erosion occur?

1. Excessive water, wind, or lack of protection exists.

2. Soil becomes saturated and fluid.

3. Wave action pulls suspended solids from the shoreline to lower levels.

4. As new soil is exposed, the process continues.

5. Areas where the water undercuts the shoreline erode faster.

When does shoreline erosion stop naturally?

When the slope of the shoreline achieves an 8:1 or 10:1 (horizontal vs. vertical) ratio, very little erosion will occur no matter what the protective surface.

Types of Shoreline Protection

Stabilization can be done in different ways. For more technical assistance, call 605-882-6202 or email the Engineering Division 

Permits can be obtained at www.watertownpermits.com. Specifically, the grading and floodplain permit online application can be found here. With questions, please call Engineering or Community Development at 882-6202. 

Click here to view a pdf of the Shoreline Stabilization Guide.

Rock Riprap

generally is the least expensive and easiest to repair and maintain. Rock riprap components consist of: the angle and length of the slope, the toe, the filter fabric, and the rock. A 3:1 or flatter back slope minimizes the force of the waves; the toe prevents water from undermining the protected area and protects the structure from damage from ice heaves and wind-driven ice sheets; a minimum of 6-8 oz. of Geotextile fabric is the protection barrier. All the other components of the design are to keep the fabric in place to do the work. The rock holds the fabric in place and prevents damage.

Seawalls (abutments / bulkheads) of steel or concrete

Bulkheads are driven into the shoreline one foot for every foot exposed. Bulkheads have two major drawbacks. The first is the high cost of the structure and the second is that they are doomed to massive failure from the forces of nature. Wood bulkheads are not recommended. Toxins leach out from the treated wood. When damaged, floating battering rams escape.

Plantings may be used to stabilize the area along with the above (hard) practices

With minimal expense, preparation, and maintenance, wildflowers, grasses, shrubs and trees will hold your property in place. Plantings can be incorporated into the riprap, above it, and / or in place of the usual high-maintenance lawn. Natural beauty, healthy protection, and wildlife could be your reward. You can create attractive yards that will require little or no fertilizer, pesticides or irrigation to keep them healthy and vibrant. Suggested species have deep root systems that trap and hold the soil to keep it from washing away.

Assessment

Annual assessments are done by project staff in the spring to prioritize sites according to highest need / worst erosion.