Coastal Erosion and the Methods Used to Reduce It

Summary

The video discusses the dynamic processes of erosion and accretion on sandy beaches, influenced by natural events and human activities. It highlights how urbanization, tourism, and coastal development disrupt natural sediment flows, exacerbating erosion. Various management strategies are explored, including beach renourishment, groynes, sea walls, and offshore breakwaters, each with its own benefits and drawbacks. The importance of preserving sand dunes, which serve as natural barriers and habitats, is emphasized, along with the challenges posed by human interference. The video calls for a balanced approach to coastal management that considers both environmental sustainability and community needs.

Takeaways

• 🌊 Beaches undergo cycles of erosion and accretion influenced by weather patterns and sea levels.
• 🌪️ Storms, particularly tropical cyclones, lead to short-term beach erosion.
• 🏖️ Calmer weather conditions allow for slower sand accretion on beaches.
• ⬆️ Rising sea levels contribute to long-term erosion, while falling levels promote accretion.
• 🏗️ Human activities, such as urbanization and tourism, significantly accelerate beach erosion.
• 🚧 Structures like groynes can trap sand but may increase erosion on the down-drift side.
• 🛡️ Sea walls protect against erosion but are costly and can harm beach aesthetics.
• ⚓ Offshore breakwaters reduce wave energy but are expensive and disrupt surfing.
• 🏡 Managed retreat involves relocating buildings to allow natural coastal processes to continue.
• 🌿 Protecting and restoring dune vegetation is crucial for preventing erosion and supporting wildlife.

Q & A

What are the primary causes of beach erosion?

Beach erosion is primarily caused by short-term events like storms, human activities such as urbanization, and long-term factors like rising sea levels.

How does human activity impact beach erosion and accretion?

Human activities such as building near the coast, mining, and dredging remove sediment, disrupt natural processes, and increase erosion rates.

What is beach renourishment and what are its drawbacks?

Beach renourishment involves adding sand to a beach; however, it can negatively impact the source beach and requires ongoing funding to replace lost sand.

What are groynes, and how do they function?

Groynes are structures extending from the shore to trap sand from longshore drift, creating a wider beach on the up-drift side but increasing erosion on the down-drift side.

What are the limitations of using seawalls for coastal protection?

Seawalls are expensive, require maintenance, can reflect waves causing more erosion, and often spoil the natural appearance of the beach.

What is an offshore breakwater and its purpose?

An offshore breakwater is a structure placed in water to reduce wave energy hitting the shore, but it can be costly and disrupt surfing conditions.

What does 'managed retreat' mean in coastal management?

Managed retreat involves councils purchasing coastal properties to allow natural coastal processes to continue, but it can be very expensive.

Why are sand dunes important for coastal ecosystems?

Sand dunes act as natural barriers to wave erosion and provide habitat for endangered species, such as shorebirds.

How does vegetation affect the stability of sand dunes?

Vegetation stabilizes dunes by trapping sand and holding it in place; without it, wind can erode the dunes and lead to blowouts.

What measures have councils taken to protect coastal dunes?

Councils have implemented fencing to protect dunes and conducted revegetation projects to enhance dune stability.