North Bull Island is located in the northern shore of Dublin Bay. It is man made and was formed as a result of positive coastal management designed to reduce silting in the Port of Dublin.
Two hundred years ago longshore drift carried sand and mud southwards form the north side of Dublin Bay. This was deposited as sand banks that partially blocked the mouth of Dublin Harbour, causing ships to go aground there. In response to this problem, North Bull Wall and the South Bull Wall were built between 1818 and 1824 to extend out from both sides of Dublin Harbour. This has had positive impacts on marine processes and on the development of Dublin:
- The Bull Walls sheltered Dublin Harbour from easterly gales, helping the development of Dublin Port.
- The North Bull Wall intercepted the longshore drift that formed sandbanks in Dublin Harbour.
- Longshore drift began to deposit sand and silt against the northern side of the North Bull Wall, which grew into the sand spit known as North Bull Island.
- Constructive waves have created a long five-kilometre sandy beach which has become one of Dublin’s most popular beaches.
- The spit being covered in sand dunes had made an ideal environment for two of Dublin’s well known golf courses – Royal Dublin Golf Club and St. Anne’s Golf Club.
But, thousands of people who visit North Bull Island have had some negative impacts on the spit’s natural environment:
- Cars driven and parked on the beach has caused compacting of sand there, which has resulted in the slowing down of the natural growth of sand dunes.
- Marran grass, which stabilises sand dunes, can be damaged by people walking and driving through the sand dunes.
- Litter that has been deposited by some visitors are visually damaging to the North Bull Island.