However, man has altered much of the natural cycle in the life of a barrier island and here's where problems occur. People love living by the sea and barrier islands are no exception. Perhaps you've seen pictures of houses falling in the sea along the east coast, especially during hurricanes. That's because strong waves act to carry away sand and anything attached to the sand. To combat this, man has built seawalls and jetties.
Seawalls have a different but equally destructive effect.
Because they are rigid, seawalls tend to reflect all of the energy of waves, increasing erosion and accelerating the speed of the longshore current. As a result, sand depletes rapidly from areas in front of seawalls. Consequently, the shore in front of seawalls gets deeper, waves get larger, and, eventually, during storms, the seawall is demolished. In effect, the seawall cripples the natural protective response of the barrier island. The end result is no beach.