The City of Norfolk, VA and the Corps of Engineers Norfolk District is working to develop a Storm Risk Management Feasibility Report/ Environmental Impact Statement & Water Quality Modeling Reports (http://www.nao.usace.army.mil/NCSRM/). Where can the Atlantic ReefMaker (ARM) be used with this strategy?
ARM can be utilized in two areas noted on the attached graphic that shows a typical profile of a coastal community. The two areas are the breakwaters/ groins and the shoreline stabilization.
ARM is appropriate in either area because acts as a breakwater structure dissipating wave energy yet allowing flushing to occur as not all of the wave energy are impeded. The structure enables low wave energy to continue through the structure whereas a breakwater structure does not. By allowing lower wave energy through the structure, sediment is allowed through the system.
ARM, in the position of the breakwater groin, can be modified to serve as an off shore, submerged artificial reef. The wave action would be altered so the wave action breaks offshore and dissipates the erosive action of the wave breaking on the shoreline and taking sand back into the ocean. As an off shore, submerged artificial reef, the ReefMaker would create a rolling wave in place of a breaking wave resulting in sand deposition. The artificial reef would also provide habitat for marine life in that it provides a protected haven around the structure for fish while also providing surface area for marine biota to adhere to and populate.
ARM is also appropriate at the shoreline stabilization area of the graphic because it dissipates wave energy instead of causing wave energy to be forced downward toward the substrate which are natural dynamics associated with riprap or a seawall. The structure allows for sediment to aggrade on the shoreline so the shoreline re-builds. Another feature of its unique design is that it allows for flushing through and between the structure to allow for natural movement of marine life. ARM stabilizes the shoreline, protects the shoreline from erosion, reduces erosion along the shoreline, improves water quality (with sediment aggradation on the shoreline), increases the stability of the shoreline over time, and provides ecosystem services, such as habitat while enhancing coastal resilience. The impact to the existing marine environment is minimized as the only contact with the substrate from ARM is the fiberglass pole as the ecodiscs are held in a position off of the substrate by a clamp. With the rip rap or seawall, the substrate is modified by the material that is placed on the substrate and the footprint of that material is significantly larger.