Beach Nourishment Our Goal: Promote better projects along the coast that balance the use of Lake Erie as a shared natural resource along with the property owners’ need for lakefront erosion protection and the benefit of access to the lake.
Beach nourishment is considered a “soft” erosion control measure that involves the placement of sand within the shore and nearshore zones to build-up beach thickness and width from shore to lake.
Beaches create a buffer between the lake and the upland. Larger beaches are able to protect against the effects of wave action better than narrow ones. Periodically nourishing a beach to increase its size will enhance the beach’s potential to lessen the effects of waves. To reduce the effects of strong storms, some beaches are nourished with an excess of sand so that they act as a “sacrificial beach.” In these cases, the beach is intended to erode during storm events, but the area behind will remain protected.
Pre-fill is a part of the design and construction of groins/groin fields and detached breakwaters. To enhance the beach quality for recreational use, some projects may include more pre-fill than would be expected to be trapped by the structure.
When conducting a nourishment project, one of the most important factors to consider is the natural beach material grain size and composition. If the placed material is smaller than the natural material, it may be quickly eroded through wave action. If the nourished material is larger than the natural sand, the impacts are more aesthetic as the larger sand size may provide greater protection but will likely look and feel different. Additional consideration should also be paid to the source of the materials.
Sand for nourishment projects should be obtained from an upland source. and not removed from the nearshore which can impact the long term availability of sand in the project area.
To maintain a beach, periodic re-nourishment may be required. The volume of fill required during each re-nourishment will depend on the current amount of sand at the location and the desired beach width after the nourishment occurs. These items are determined on a site-by-site basis, often with the assistance of a professional. Vegetation of the beach area to create dunes can also extend the life of a beach nourishment project.
During or after beach nourishment projects, the sand may migrate downdrift, potentially impacting downdrift or adjacent shores. The potential impacts of beach nourishment should be assessed to ensure that downdrift areas are not adversely impacted. For example, if downdrift areas include docks or boat launches, the movement of additional sand into these areas could result in shoaling, limiting the water depth and decreasing the functionality of the dock or boat launch.
When a shore structure is intended to create or protect a beach, the design typically includes the placement of sandy sediment, often referred to as pre-fill or beach nourishment. The amount of sand pre-fill required is roughly the amount expected to be captured by the new structure under average water levels. By pre-filling the beach area with sand, the amount of sand removed from the littoral system by the structure is minimized. Available sand in the area is allowed to flow past the structure and be distributed along the downdrift shore.
The design of a beach nourishment project requires the services of a professional engineer and in most cases a contractor is needed to deliver and place the sand. In very rare instances of re-nourishment some property owners may be able to conduct the work without hiring a contractor. This would include a nourishment project conducted over a relatively small area where there is adequate access to the beach. Since these instances are infrequent, nourishment or pre-fill projects are considered to be methods requiring the hiring of a consultant.
Beach Nourishment Essential Information
Function: Serves to build up the beach width to ensure the beach and upland can withstand stronger storm activity (wave erosion). Prefill is used with detached breakwaters and groin/groin fields to minimize the amount of native beach material that will be trapped by the structures to lessen impacts to downdrift areas.
Appearance: Sand and cobble are used. Which is dependent upon the size and composition of the native sand at the placement site.
Materials: Sediment of the same size or larger must be used; otherwise the sediment will leave the beach area too quickly.
Issues: Sediment size should be matched. Sediment sources can be difficult to find or may be costly (sources may include upland areas and dredge materials).