How Coastal Erosion Works

Summary

This video by Practical Engineering explores coastal erosion and how we combat it. The coastline is a dynamic area where the ocean gradually erodes land, especially through the force of waves. The video discusses different strategies to address this problem, including hard armoring structures like seawalls and breakwaters, as well as softer solutions like planting mangrove forests and beach nourishment. As climate change causes rising sea levels, coastal erosion becomes an increasingly significant issue. The video emphasizes thoughtful engineering and solutions to protect coastal areas and adapt to ongoing changes.

Takeaways

• 🌊 Humans are naturally drawn to the coast, where land meets the sea, making it a dynamic and fascinating area.
• 🏖️ Coastal erosion is a natural process, primarily driven by waves, which causes land to erode much faster than other areas.
• 🌊 Waves are a major cause of coastal erosion, with their force displacing soil, rock, and sediment along the shoreline.
• 🌪️ Storms like hurricanes significantly accelerate coastal erosion due to stronger waves and winds.
• 🏢 Coastal development is at high risk due to erosion, which threatens homes, businesses, and infrastructure near the shore.
• 🧱 Solutions like seawalls, bulkheads, groins, and breakwaters are used to protect coastlines but can have unintended environmental impacts.
• 🌱 Softer solutions include planting mangrove forests to absorb wave energy and beach nourishment, which involves adding sand back to eroded areas.
• 🏝️ Retreat strategies involve moving infrastructure away from the coastline or purchasing coastal land to act as a buffer.
• 📈 Sea levels are expected to rise by up to 3 feet in the next 50 years, worsening coastal erosion and inundation risks.
• 🌍 Coastal erosion is a growing challenge for property owners, governments, and engineers, requiring thoughtful, long-term solutions.

Q & A

What makes the coastline such a fascinating place for humans?

The coastline is inherently interesting because it represents the meeting point between two vast elements: land and sea. This dynamic interaction captivates humans, much like the allure of campfires, drawing people to observe and experience it.

How does coastal erosion differ from erosion that happens inland?

Coastal erosion occurs much faster than inland erosion due to the relentless force of waves and currents, which move large amounts of sediment quickly. The process is accelerated by storms and the constant motion of the sea, whereas inland erosion usually takes place over longer timescales.

What is the primary cause of coastal erosion?

The primary cause of coastal erosion is the destructive force of waves. Waves exert significant pressure on the coastline, washing away loose sediment and eroding rock formations over time.

How do waves contribute to the erosion process?

Waves carry large amounts of force due to the heavy mass of water. This force is enough to break apart soil and rock, and when combined with sand and sediment in the water, the waves act as a grinding force that wears away at the coastline.

What are some of the solutions used to combat coastal erosion?

Engineers combat coastal erosion with hard structures like seawalls, bulkheads, and groins, as well as softer approaches like planting mangrove forests and conducting beach nourishment to replenish lost sand.

What are some unintended consequences of using hard structures like seawalls to prevent erosion?

Hard structures like seawalls can reflect waves, which worsens erosion in other areas down the coast. Groins can also disrupt natural sediment movement, causing erosion on the downdrift side.

Why is beach nourishment used as a solution, and what are its drawbacks?

Beach nourishment replenishes lost sand, providing a buffer between the sea and human development, as well as maintaining recreational beaches. However, it has environmental impacts and is not a permanent solution, requiring periodic renewal.

How does planting mangrove forests help reduce coastal erosion?

Mangrove forests help stabilize coastlines by absorbing wave energy, which reduces the impact of waves on the shore and protects against erosion, especially during tides and storm surges.

What is the projected rise in sea levels over the next 50 years, and why is it a concern?

The National Oceanic and Atmospheric Administration projects a rise in sea levels of at least one foot, and possibly more than three feet, by 2070. This poses a serious threat to coastal areas, as higher sea levels increase exposure to erosion, tides, and storm surges.

What is the concept of 'retreat' in terms of protecting coastal infrastructure from erosion?

'Retreat' involves moving infrastructure away from the shore or condemning property to serve as a buffer zone, rather than trying to fight against the natural process of erosion. This strategy can prevent future losses from erosion and rising sea levels.