Coastal Erosion. What is coastal erosion? Coastal erosion can be either a: rapid-onset hazard occurs very quickly, a period of days to weeks slow-onset hazard occurring over many years, or decades to centuries. What causes coastal erosion? Where does coastal erosion occur in Australia? Single storm events have caused coastal erosion, such as that associated with East Coast Low storms in and that damaged beachfront properties in Sydney.
A series of large storm events in led to even more extensive damage to coastal properties and infrastructure in this region. Slow onset: The Twelve Apostles along the Great Ocean Road are a result of landscape change and coastal erosion over millenia. There were originally 12 limestone features with 8 now remaining. These structures remain vulnerable to further erosion from waves.
Around the Australian coast, nearly 39 buildings are located within one hundred metres of 'soft' shorelines and are at risk from accelerated erosion due to sea-level rise and changing climate conditions as at What is Geoscience Australia's role in reducing risk to Australians from coastal erosion?
Geoscience Australia: develops an understanding of natural hazards and community exposure to support risk mitigation and community resilience provides authoritative, independent information and advice to the Australian Government and other stakeholders to support risk mitigation and community resilience maintains and improves systems for effective natural disaster preparedness, response and recovery contributes to Australia's overseas development program.
In particular, Geoscience Australia: develops national-scale datasets as a fundamental input to coastal erosion hazard and risk assessments develops methods and tools that can support the development of coastal risk assessments supports national initiatives to manage the coastal environment.
A sandy beach that gradually slopes out of the sea dissipates the wave's energy, while a cliff that rises out of the ocean without any sand or sediment at its base will be hit with the full force of the waves and forced to quickly retreat.
The shore's can be equally important. Materials that resist transport and have a strong internal structure, like large volcanic rocks, slow erosion, while loosely packed sediment, such as the fine sand found along the coast of Florida, washes away quickly.
Vegetation plays an dual role, with different types aiding or hindering erosion. Mangrove trees have sprawling root systems that can secure sand, while lichens can break down large, hard rock into pieces that can be swept out to sea. Human activity has a dual role as well; man-made climate change has increased erosion on a global scale because of higher sea levels, but we also have the power to slow down and restore coasts which are receding.
This can be a cost-saving strategy when the eroding land is not very desirable and there are only a few residents to move. By contrast, the "hold the line" strategy keeps residents in their place and focuses on maintaining the current shorelines.
This can be implemented with hard defenses,like seawalls, which are generally cheaper and easier to build than soft defenses, such as replenishing beaches with sand. Counties in Florida have been spending millions annually on replenishing beaches which are critical to the state's multibillion dollar tourism industry.
The "move seaward" and "limited intervention" strategies focus on building structures toward the ocean away from the current coast. Moving seaward, which involves building dunes or seawalls in a place that creates extra land and pushes the ocean back, is a very costly strategy, but it can reclaim coastal land and ecosystems which were victims of erosion.
Limited intervention uses the natural features of the area to reduce erosion, such as encouraging and promoting wetland formation or barrier coral can reduce erosion of the higher valued coastline.
Promoting wetland growth has been a large part of Louisiana's effort to protect New Orleans and other areas near the coast from storm surges and flooding. Climate change, rising sea levels and increased demand for valuable beaches and coastal areas are only raising the stakes in the continuing fight against the ever-encroaching ocean. Graham, D. Turner, I. Journal of Coastal Research, 13 4 , University of Florida.
University of Florida News. August 14, By: Sci Bytes. Taken on August 9, , the photo on the left shows how ocean waves have undercut the land nearest the shore. Grassy turf extends out over a wave-cut notch. Taken on June 20, , the photo on the right shows what often follows such undercutting: chunks of coastline tumbling into the sea. In the past, protecting the coast often meant "hardening" the shoreline with structures such as seawalls, groins, rip-rap, and levees. As understanding of natural shoreline function improves, there is a growing acceptance that structural solutions may cause more problems than they solve.
Additional reasons to avoid structural protective measures include the high costs to install and maintain them, state or local prohibitions against them, their propensity to cause erosion to adjacent beaches and dunes, and the unintended diversion of stormwater and waves onto other properties.
Many states have shifted toward non-structural shoreline stabilization techniques. Unlike structural projects, nature-based or "green infrastructure" protection measures enhance the natural ability of shorelines to absorb and dissipate storm energy without interfering with natural coastal processes.
One common strategy for dealing with coastal erosion is beach nourishment—placing additional sand on a beach to serve as a buffer against erosion or to enhance the recreational value of the beach. However, beach nourishment has also become a controversial shore protection measure, in part because it has the potential to adversely impact a variety of natural resources.
Consequently, these projects must comply with a wide range of complex laws and regulations. Beach nourishment is also expensive: check the Beach Nourishment Viewer to explore details about sand placement efforts for more than 2, beach nourishment projects since Adding sand to a beach does not guarantee that it will stay there. Some communities bring in huge volumes of sand repeatedly, only to see it wash out to sea in the next season's storms.
When completed in , the beach was 60 feet wide and sloped up to 5 feet above mean low water. Nonetheless, many communities still practice beach nourishment. Army Corps of Engineers USACE is authorized to carry out beach nourishment for shoreline protection: their Beach Nourishment site describes the benefits of adding sand to beaches.
Recently, the U.
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