How do both jetties and seawalls help manage beach erosion?

Question

Both bring sand to the beach from offshore.
Both provide flood protection in the event of high waves.
Both use plants to help keep sand on the beach.
Both are hard structures that reduce erosion caused by waves.

Answer 1

However, there are some differences in how jetties and seawalls help manage beach erosion:

- Jetties: Jetties are long, narrow structures built perpendicular to the shoreline and extending into the water. They are designed to trap sand that is transported by longshore currents and waves. Jetties work by interrupting the natural movement of sand along the beach and creating areas of partial shelter from waves. As a result, sand accumulates on the updrift side of the jetty, which can widen the beach and reduce erosion. However, jetties can also interfere with the natural processes that shape the beach and create an imbalance of sand distribution, which can cause erosion on the downdrift side of the jetty. Moreover, jetties can affect the access and navigation of boats, alter the mobility of aquatic organisms, and cause changes in water circulation and sediment transport.

- Seawalls: Seawalls are vertical concrete or masonry structures that are built parallel to the shoreline and designed to protect coastal development from wave attack and flooding. Seawalls work by reflecting waves back into the water and preventing them from reaching the shore. As a result, seawalls can provide a stable base for buildings and infrastructure and reduce the risk of property damage and loss of life. However, seawalls can also accelerate erosion by increasing wave energy along the base of the wall, creating a scouring effect that removes sand and sediment from the beach. Additionally, seawalls can disrupt the natural gradient of the beach and cause changes in sediment transport, which can affect the ecology and geomorphology of the coastal zone.

In summary, both jetties and seawalls can help manage beach erosion by reducing wave energy and stabilizing the beach, but they also have drawbacks and limitations that must be carefully considered in coastal management. A comprehensive approach to beach erosion management should involve a combination of hard and soft measures, such as beach nourishment, dune restoration, vegetation planting, and setback policies, to ensure that the beach remains resilient, adaptable, and sustainable over time.

Answer 2

which one of these are right Both bring sand to the beach from offshore.
Both provide flood protection in the event of high waves.
Both use plants to help keep sand on the beach.
Both are hard structures that reduce erosion caused by waves.

Answer 3

All of the statements are correct.