Final answer:
Four techniques to reduce beach erosion include installing groins, erecting seawalls and revetments, beach nourishment, and creating or restoring wetlands.
Step-by-step explanation:
Beach erosion is a significant environmental issue that can be mitigated using various techniques. Groins can be installed perpendicular to the shore to trap sand from longshore currents. Seawalls and revetments are erected parallel to the coast to protect the shore from wave action. Beach nourishment involves adding sand and sediment to the beach to replace what is lost to erosion. Lastly, creating or restoring wetlands can provide a natural buffer against wave energy and reduce the impact of erosion.
While these methods can be effective, it's important to note that some, like seawalls and revetments, can have a detrimental impact on natural coastal ecosystems if not designed and placed carefully. Innovative solutions that work with natural processes, such as beach nourishment and wetland restoration, are often preferred for their ecological benefits and sustainability.