The cause of the sand build-up is the natural shape of the coast. Banks Peninsula acts as a large shelter for Pegasus Bay. The peninsula causes the sea current to form a large eddy (circular motion) in Pegasus Bay, causing sand to accumulate. It also protects the bay from the southerly storms and prevents the northward movement of sand up the coast.
20,000 years ago the shoreline of Pegasus Bay was 50 kilometres further out to sea and 130 m lower. As the climate warmed and cooled over time, the continental shelf was continually flooded until the shoreline became stable at its current position about 4500 years ago. This means that the coast as we know it – its landforms, estuaries and sediment, is relatively young.
Much of Pegasus Bay is open flat beach area backed by extensive dunes. The dunes need to be eight metres above mean sea level to be effective against storms.
Sand dunes protect the land from the forces of the sea during storms. Without healthy sand dunes, settlements along Pegasus Bay could be threatened.
Anecdotal information and observations indicate an increasing number of recreational vehicles (4wd, 4, 3 and 2 wheeler bikes) accessing the beach areas of Pegasus Bay. It is accepted that a large number of these are using access for low impact purposes such as getting to fishing and whitebaiting areas and for launching and recovery of craft. However, there are other groups and individuals that use the beach, and the dune areas, for recreational driving. Again, a large number of these are reasonably responsible but the issue stems from two factors:
The principal issue contains a number of sub-issues:
Sandy beaches attract people for a number of reasons...
Walking, playing on the beach, walking dogs, fishing, horse riding, surfing, 4 wheel driving, jet skiing, boating.
All these activities require people, animals or vehicles to move across or near the coast.
They could disturb nesting birds or destroy plants that grow on sand dunes.
Port operations, sewage outlets.
Ships and other sea vessels may contribute to marine pollution.
Population growth near the coast means an increase in sewage discharge. This could lead to contamination if not treated correctly.
Building housing for permanent or holiday homes, businesses, structures built right on the coast such as jetties or sea walls.
These activities may attract more people for recreation. Structures built on the coast could interfere with normal coastal processes.
The strategy contains recommendations on whether or not vehicles should be allowed to access beaches on the Northern Pegasus Bay coast between the Waimakariri River mouth and 'The Rocks' north of the Waipara River.
It is a non-statutory strategy, which means its recommendations are not binding until the four organisations who look after this coastline (Environment Canterbury, Hurunui District Council, Waimakariri District Council and the Department of Conservation) agree to adopt the strategy and its recommendations.
Christchurch City beaches are already restricted to vehicle access.
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