The aim of this report is to investigate Long Reef and Collaroy Beach’s coastal management.
The Importance of Vegetation
Sand dunes are a valid indication of the quality of the soil and the surrounding ocean. When vegetation is established in sand dunes, it stabilises it- i.e. gives the dunes structure. This structure helps prevent erosion by using the plant life to trap the sand. Without these plants (and ultimately the sand dunes) sand will be subject to many natural forces without protection, meaning any major storm could theoretically remove large amounts of sand from the beach with no natural means of replenishing it. Long Reef Beach is commendable in the amount of vegetation it has produced. Because of this the area will not be prone to dangerous levels of erosion. However, Collaroy Beach had very little vegetation and smaller sand dunes. As no definitive structure is given to the dunes at Collaroy Beach it is much more prone to erosion than Long Reef Beach. The buildings found on the edge of Collaroy Beach would benefit from structured sand dunes as they will not be as prone to storm damage and other weather forces.
The Formation of Sand Dunes
Sand dunes provide a means of protecting the land behind it from various oceanic processes, i.e. wave and wind formations. Therefore it is important for sand dunes to be found on coastlines. Both wind and water are essential processes in the formation of these dunes, referred to as Aeolian and hydro spherics respectively. Sand is carried via the ocean and is washed up on coasts, whilst longshore drift further moves and deposits this sand in various areas. This process describes the formation of sand dunes. Wind further carries the sand up inclines, increasing the area of the dunes. Without these sand dunes, it would be the land being eroded and continuously fighting the Aeolian and hydro spherics forces, instead of the sand. At Collaroy Beach, the many buildings in the area would be worn away by the waves if it were not for the sand dunes.
Impact of Human Action
Sand dunes can be greatly affected by humans. Humans can aid sand dunes by introducing vegetation to them; on the other hand humans can be detrimental to sand dunes simply by walking over them. Vegetation in sand dunes is beneficial as they provide support to the sand dunes and trap the sand. On Long Reef Beach, the tall plants act as a barrier for the dunes, protecting the sand from winds. Walking over sand dunes continuously disrupts sand formations which potentially could have taken years to form. Walking over dunes can also prevent further vegetation from forming.
In both Long Reef Beach and Collaroy Beach, coastal landforms such as lagoons, sand dunes and beaches have been formed. Dee Why Lagoon is a lagoon found behind Long Reef Beach. It was created using the process ‘Longshore Drift’. Longshore drift refers to the process of moving sand along the coastline. It produces many coastal features, such as bars, tombolos and spits. It created the Dee Why lagoon by silting up the area where Dee Why lagoon and the ocean meet, creating a separate body of water. If humans interact with the lagoon, that is, cause the lagoon’s water to overflow or move, a large portion of sand can be lost. Beaches that have been developed by Aeolian and hydraulic processes are vital in protecting the land, and in some cases, buildings. They are created when sediment (generally sand) is deposited along the shoreline. When this sand is deposited along the coast it generally goes further inland via wind processes. Humans have been known to pollute beaches, ruining the beach’s ecosystem, causing organisms to relocate or in some cases die out in that local area. Beaches are commonly linked with sand dunes. The sand dunes have acted as a barrier for Collaroy Beach and Long Reef Beach, protecting Collaroy’s buildings and the areas behind Long Reef, such as a local golf course. By...