Why Add Sand to the Beach?

Beach nourishment, or beach filling, is the practice of adding large quantities of sand or sediment to beaches to combat erosion and increase beach width. Often referred to as a “soft armoring” technique, it is sometimes viewed as a superior alternative to hard armoring because it avoids some of the major pitfalls associated with hard structures like seawalls. With sea level rise and storms threatening to erode sandy beaches, it is likely that nourishment will become more prevalent as managers seek to protect valuable coastal property.

What Are the Consequences of Beach Nourishment?

• The sudden input of massive amounts of sand can kill all the animals living on the beach.
• During nourishment, the beach becomes a major construction zone. The heavy machinery used to truck in and distribute new sand also kills beach animals and disturbs wildlife.
• The new sand may not be the same grain size or chemical makeup of the natural sand, changing the habitat that beach animals rely upon.
• The resulting catastrophic loss of intertidal prey resources for wildlife such as shorebirds means these birds have to travel to another beach to find food.
• The time needed for a beach ecosystem to recover from a single beach filling episode is not known, even when fill sand is the right size and type. Repeated or frequent episodes of nourishment can impede recovery of the beach community and ecosystem. 
• Some types of animals, such as sand crabs, start their lives as free-floating larvae that drift through the ocean with the currents, so they can float in from elsewhere and recolonize the beach in a year. However, if the nourishment episode coincides with this event, then the population will not have a chance to begin repopulating the beach until the following year. 
• Long-lived species that do not reproduce often, such as Pismo clams, may take decades to recover.  
• Beach animals that carry their young in pouches (rather than producing free-floating young), such as amphipods and isopods, depend entirely on resident populations for recovery. These animals may require human help to return to a beach impacted by nourishment.
• As the ocean starts eroding the introduced sand, the water offshore can become muddy, potentially smothering marine life and changing coastal water quality. Critters that rely on relatively clean, clear water, like clams, can die off in large numbers. The eroding sand can also cover kelp forests, rocky intertidal reefs and seagrass beds, and it can end up clogging the mouths of estuaries, altering vital tidal exchange. 
• The grain size of the introduced sand can influence how fast it erodes, leading to changes in beach shape.
• The added sand is often mined from places underwater or in riverbeds. Mining can alter those environments and make that limited resource unavailable for future projects.