Beach Replenishment and Impacts on Beach Ecosystems
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Description
Sea-level rise is expected to continue over the next century. In San Diego, many beaches already experience high tide flooding and coastal erosion. Sea level is projected to rise 5 to 14 times faster by the end of this century. One remedy to coastal erosion is beach replenishment. This method transports sand onto beaches to increase beach width thereby slowing sand loss and protecting coastal properties. Despite its widespread use, little is known about how beach replenishment affects sandy beach intertidal invertebrates, which are key components of beach ecosystems. In this study, we used a BACI design (Before After Control Impact) to monitor the intertidal invertebrate community and sediment characteristics (beach slope, grain size, organic content) at a beach replenishment site in Del Mar and at an adjacent control site in Solana Beach, CA both before and after replenishment. In the short term, we found an immediate impact at beach replenishment sites with an increase in beach slope and changes to community structure. This change, however, was short-lived as storm activity shortly after the replenishment project quickly removed replenished sand and decimated invertebrate communities at both replenished and control locations. Future studies should look at the longer-term impacts of beach replenishment as well as how replenishment may affect beaches at different times of the year.
Beach Replenishment and Impacts on Beach Ecosystems
Sea-level rise is expected to continue over the next century. In San Diego, many beaches already experience high tide flooding and coastal erosion. Sea level is projected to rise 5 to 14 times faster by the end of this century. One remedy to coastal erosion is beach replenishment. This method transports sand onto beaches to increase beach width thereby slowing sand loss and protecting coastal properties. Despite its widespread use, little is known about how beach replenishment affects sandy beach intertidal invertebrates, which are key components of beach ecosystems. In this study, we used a BACI design (Before After Control Impact) to monitor the intertidal invertebrate community and sediment characteristics (beach slope, grain size, organic content) at a beach replenishment site in Del Mar and at an adjacent control site in Solana Beach, CA both before and after replenishment. In the short term, we found an immediate impact at beach replenishment sites with an increase in beach slope and changes to community structure. This change, however, was short-lived as storm activity shortly after the replenishment project quickly removed replenished sand and decimated invertebrate communities at both replenished and control locations. Future studies should look at the longer-term impacts of beach replenishment as well as how replenishment may affect beaches at different times of the year.