BEsT MANAGEMENT PRACTICEs HANDbooK - Tahoe BMP

8.5 BEACH NOURISHMENT AND REPLENISHMENT8.5.1 OVERVIEWBeach nourishment and replenishment is the artificial placement of natural material in the shorezone toprotect the backshore and upland from wave action. The replenishing material is normally brought fromsources outside of an eroding system to address the problem of a sediment deficit. If sediment from theproposed project site is deemed uncontaminated, it can be used as a replenishment material. Sand, gravel,and cobble are the typical materials used to nourish beaches. Beach nourishment can consist of theplacement of a berm directly on the shore or of a feeder beach designed as a source of sediment fordowndrift areas.Both beach nourishment and replenishment serve to bolster the buffer absorbing wave energy to protectthe backshore or to provide additional recreational space by extending the beach area or restoring it toprevious dimensions. Beach nourishment can be used in conjunction with other shorezone protectivestructures to help minimize their negative effects (e.g., bulkheads, lake walls, and anchored breakwaters).Beach replenishment differs from nourishment in the type of material placed on the beach.Replenishment involves a direct replacement of the material lost with similarly sized material (e.g., sandreplenished with sand). Nourishment involves addition of material that may be the same size, but ispreferably larger and of greater density than the native material so that it stays in place for longerdurations between nourishment cycles (e.g., gravel beach nourished with small cobble).Beach nourishment is applicable to beaches, sometimes revetments, and other static protective structuresexperiencing erosion and undermining. There are also several aspects of a beach nourishment project thatspecifically address the future integrity of the foreshore beach or backshore terrace. These includeperiodic re-nourishment, advance nourishment, and emergency bank repair and maintenance.8.5.2 BEACH NOURISHMENT AND REPLENISHMENT: ADVANTAGES AND DISADVANTAGESBeach nourishment projects generally have a comparatively low initial cost, but maintenance and periodicre-nourishment increases the overall costs beyond the original capital outlay. Beach nourishment can be acost effective and aesthetically pleasing method of protecting the shoreline but its on-going success iscontingent upon monitoring and response management.The placement of beach fill material usually impacts the biology of the area that is directly involved in theproject. Biological impacts may also be created in adjacent areas from the turbidity created by the fillingprocess. Monitoring turbidity in the foreshore and nearshore of the project area will be necessary to assessthe impact of the placement of the replenishing beach fill material on the local biota and flora. 35Overall, there are various advantages and disadvantages to beach nourishment and replenishment (Referto Table 8-12).35USACE, 1995, Engineer Manual EM 1110-2-1810, Engineering and Design: Coastal GeologyTRPA BMP HandbookCHAPTER 8: Shorezone Protective Structures and BMPs2012 8.5 Beach Nourishment and ReplenishmentPage 8-41