geo essay Flashcards
intro (aus/in order to/a coastal ecosystem/coastal management stratgeies/these beaches)
Australia’s extensive coastline hosts diverse coastal ecosystems that are of paramount ecological and economic importance, which are suffering from issues such as erosion and storms, invasive species and urban development. In order to sustain and support the natural environment and protect local properties, a variety of coastal management strategies are utilised to minimise the degradation of the coast. A coastal ecosystem is shaped by the atmosphere, lithosphere and hyrdoesphere, and refers to the dynamic interactions of living organisms and their environment where the ocean meets the land,encompassing a variety of habitats including beaches, dunes, tidal zones and estuaries. Coastal management involves implementing strategies such as structural measures or regulatory approaches to protect and preserve these ecosystems while addressing potential threats, particularly in areas prone to erosion, such as the Collaroy and Narrabeen beaches in New South Wales. These beaches, located on Sydney’s northern coast, have unique ecosystems and management strategies that have worked to resolve the damage these areas have suffered throughout the years due to extreme conditions.
paragraph 1 - topic snetence (Australia employs)
Australia employs various coastal management strategies, building hard engineering structures that are more invasive such as groynes to address erosion and using soft engineering methods such as dune stabilisation that more naturally protect coastal areas.
paragraph 1 - groynes (7 sentences: groynes/they are selected/this makes them the preferred/compared to offshore breakwaters/as a hard managemnt startgey, groynes do have a/their success.. but as a whole, groynes***/with only one major)
Groynes are physical structures, usually made of wood or rock, that are built over the beach perpendicular to the shoreline, and designed to alter wave patterns with the ultimate goal of preventing coastal erosion. They are selected for use on the basis that they effectively trap sand and sediment and help build up a larger section of beach in front of eroded areas. This makes groynes a preferred choice in areas where maintaining recreational beaches and coastal infrastructure is a primary objective, as they can enhance the aesthetics of the coastline, attract tourists, and support local economies. Compared to offshore breakwaters, groynes are more cost-effective and less intrusive which can be an important consideration in areas with significant maritime traffic. As a hard engineering strategy, g roynes do alter coastal ecosystems by changing natural sediment transport patterns, which potentially impacts seafloor habitats, nearshore ecosystems, beach dynamics and the distribution of beach-nesting species, as this often results in a thinner beach further down the coast. Their success depends on the goal of the project, but as a whole, groynes have been shown to be effective in maintaining targeted beach areas and protecting coastal infrastructure by mitigating coastal erosion around the area it has been placed. With only one major disadvantage of thinning the beach down-drift, their cost-effectiveness, evident impact and natural implementation evidently contribute to this strategy’s success.
paragraph 1 - dune stablisation (6 sentences: additonally, dune stablisation, whic incolve/in ecologically senstive areas/in copmarison to phsycial structures such as/dune stabilsatins can also provide/their success is largely within the scope of)
Additionally, dune stabilisation methods, which involve planting vegetation to stabilize sand dunes, are also used to reduce erosion and protect native species. In ecologically sensitive areas where councils wish to focus on the conservation of natural dune systems and vegetation, dune stablisation is used as it preserves the local flora and fauna and also reduces and absorbs the energy of waves. In comparison to physical structures such as revetments, which are often chosen in areas with severe erosion when the priority is protecting infrastructure, dune stablisation is more suitable for maintaining the natural beach-dune system, which can serve as a buffer against erosion and storm impacts. Dune stablisations can also provide habitat for marine and terrestrial species, contributing to ecological diversity within the coastal ecosystem. Their success is largely within the scope of ecological conservation and aesthetics, as they have not been as successful at directly preventing the degradation of the coastline when compared to sturdier, engineered structures.
paragraph 1 - link
Groynes and dune stablisation have both been shown to have respective benefits that work to protect and preserve the coastline in a unique manner.
paragraph 2 - topic sentences (4 steneces: additonally, cms must often be tailored/these beaches are situated/however, they have been vulnerable to/at these beaches, the noerthen beaches council has utilised)
Additionally, coastal management strategies must often be tailored to specific local conditions, such as Collaroy and Narabeen. These beaches are situated on the northern nsw coast, and are characterised by their picturesque coastline and recreational significance. However, they have been vulnerable to coastal erosion and have experienced significant property damage over the years due to extreme weather, tides and low-pressure systems that put public safety at risk, making it essential to implement effective coastal management strategies. At these beaches, the Northern Beaches council has utilised sediment recycling and seawalls to promote public access and safety.
paragraph 2 - sediment recycling (7 setneces: Sediment recycling involves/the northenr beaches council/the streagy was more cost-effective and suited/the use of this stragey has/when executed/peroridc renourishment/trhoguh its ability to)
Sediment recycling involves relocating and reusing sand or sediment from regions where it accumulates, such as Narrabeen lagoon, and redistributing it to mitigate erosion by widening the beach and nourishing dunes. The Northern Beaches council utiilised sediment recycling to maintain recreational appeal as it was more environmentally friendly than hard structures like seawalls. The strategy was more cost-effective and uited to the area than the alternative of adding sand externally, as a sediment source - Narrabeen lagoon - was located within the same system and conveniently required sand to be removed from its entrance in order to mitigate its risk of flooding. The use of this strategy has minimised the disruption to the coastal ecosystem, providing a temporary solution to erosion, but it may alter the natural sediment balance and affect the habitat for beach-nesting birds and turtles if it is carried out excessively. When executed accordingly, it yields a multitude of benefits for the ecosystem, stabilising dunes, creating new habitats for various marine and terrestrial species and overall counteracting the effects of coastal erosion by replenishing the sand that has been lost. Periodic renourishment will be needed to maintain its effectiveness, but it has provided immediate protection to properties and maintained the beaches by creating a buffer that has accumulated into habitats and feeding grounds for species and reduced the risk of damage from storm events. Through its ability to sustainably maintain recreational beaches, support tourism, and provide a natural buffer against erosion, sediment recycling has been successful in markedly improving the condition of the coastline along Narrabeen and Collaroy.
paragraph 2 - seawalls (13 senetnces: moreover, two types of/rock revetment/vertical concrete seawllas/the council chose these as/the rock revetment seawall maintinas/when there is a need to/they were ocnsutruecfor their durbailtiy/seawalls offer/they als ocontrubite to habitat/the vertical concrete seawall in partic/the seawalls at/however, this has come)
Moreover, two types of seawalls are used at these beaches: rock revetment seawalls and vertical concrete seawalls. Rock revetment seawalls are sloped structures consisting of sandstone and basalt that dissipate wave energy gradually. Vertical concrete seawalls are constructed from reinforced concrete, with a ‘wave return’ lip at the top that is designed to protect against storm erosion, damage and undercutting. The council chose these as they were able to protect valuable properties and infrastructure from the destructive force of the ocean. The rock revetment seawall maintains the natural appearance of the coastline and is specifically engineered to absorb and deflect wave energy, reducing erosion along the shoreline. When there is a need to safeguard critical infrastructure in areas under significant threat of erosion, revetments are employed because of their ability to simultaneously provide direct and robust defense and ensure the contintuity of recreational services. They were constructed for their durability in providing protection from erosion to private properties, and are less maintenance for homeowners. Seawalls offer effective short-term protection but depending on their design, maintenance and management, can disrupt the natural coastline, potentially harming marine habitats through changing wave refraction and altering sediment transport. They also contribute to habitat fragmentation by creating a physical barrier between the shoreline and the coastal ecosystems behind them, affecting the migration and breeding patterns of coastal species. The vertical concrete seawall in particular is viewed to have an obtrusive aesthetic impact on the natural beauty of the Northern Beaches. The seawalls at Collaroy and Narrabeen have been successful in providing immediate protection to properties and infrastructure along the coastline, preventing and minimising erosion in the areas directly behind the walls. However, this has come at the cost of ecological changes in the local environment, and they must face challenges presented by the dynamic nature of coastal environments that will limit their future success.
paragraph 2 - link (the strats applied at coll and)
The strategies applied at Collaroy and Narrabeen showcase the need for adaptive, specialised management strategies so that coastal ecosystems can be effectively maintained.
conclusion (4 sentences: overall, cms are effective depending/the strategies utilised across australia/cms employed acrros coll and narra/for the short-term success of cms to be maintained//)
Overall, coastal management strategies are effective depending on their location and whether they respond to the most pressing needs for that area. The strategies utilised across Australia sucj as groyjes and dune stabilistaion play a crucial role in protecting valuable coastal ecosystems while addressing challenges posed by erosion and development. Coastal management strategies employed across Collaroy and Narrabeen demonstrate how strategies chosen must reflect a balance between property protection and ecosystem preservation. For the short-term success of coastal management strategies to be maintained, their long-term sustainability and ecological impacts must be continuously assessed and adapted to ensure the health and resilience of coastal ecosystems in the future.
