Coastal Processes: Weathering and Erosion

This page delves into the various processes that shape coastal landscapes, including chemical weathering, mechanical weathering, and mass movement.

Chemical weathering involves the breakdown of rock by changing its chemical composition. An example is carbonation, where rainwater containing dissolved carbon dioxide forms carbonic acid, which reacts with and dissolves rocks containing calcium carbonate.

Vocabulary: Chemical weathering is the process of rock breakdown through changes in its chemical composition, such as carbonation.

Mechanical weathering breaks down rock without changing its chemical composition. Freeze-thaw weathering is an example, occurring when temperatures fluctuate above and below 0°C, causing water in rock cracks to freeze and expand, splitting the rock.

Mass movement is the shifting of rocks and loose material down a slope due to gravity. This process can cause rapid coastal retreat and is more likely to occur when the material is saturated with water.

Highlight: Understanding these coastal processes is essential for developing effective coastal protection methods.

The page also introduces the concepts of destructive and constructive waves, explaining their different characteristics and effects on coastal erosion and deposition.

Definition: Destructive waves have a high frequency and steep profile, eroding the coast, while constructive waves have a low frequency and deposit material on the shore.

Managing Coasts: Hard Engineering, Soft Engineering, and Managed Retreat

This page introduces three main approaches to coastal management: hard engineering, soft engineering, and managed retreat. Each method has its own set of advantages and disadvantages.

Hard engineering involves using artificial structures to control natural processes. Examples include groynes and sea walls. While effective at stopping the sea, these methods can be expensive and may have negative environmental impacts.

Definition: Hard engineering examples include groynes and sea walls, which are artificial structures used to control coastal erosion.

Soft engineering employs less intrusive, more environmentally friendly methods that work with natural processes. These approaches are becoming increasingly popular due to their lower cost and reduced environmental impact.

Vocabulary: Soft engineering coastal management refers to techniques that work with natural processes to protect coastlines, such as beach nourishment and dune regeneration.

Managed retreat is a strategy that allows for controlled retreat of the coastline, often involving allowing the sea to flood certain areas. This approach is gaining popularity as a sustainable long-term solution.

Highlight: Managed retreat is becoming an increasingly popular strategy for coastal management, as it allows for a controlled and sustainable approach to dealing with coastal erosion.

The page also discusses specific advantages and disadvantages of various hard engineering structures, such as groynes and sea walls. It notes that hard engineering is becoming less common due to its high costs, maintenance requirements, and potential negative impacts on natural coastal processes.