When seawalls are built using traditional methods, they typically result in damage to or loss of important habitats such as saltmarsh, mangroves and seagrass beds. These habitats are vital to many animals, such as fish and shorebirds, providing food and shelter. Seawalls are also poor replacements for natural foreshores because:
- the types of habitat and area available to plant and animal life are reduced dramatically (see diagrams below)
- the ability to filter pollutants from runoff is lost, leading to poorer water quality
- they can change flow and wave patterns, resulting in deepening in front of the seawall and erosion further along
- the shore.