Coastal Flashcards
Name and describe the major parts of a beach (beach face, berm, etc.)
Beach Face: The sloping portion of the beach that extends from the water’s edge to the berm. It is continually reshaped by wave action and tides.
Berm: A raised area of sand or gravel running parallel to the shoreline, marking the highest point reached by normal high tides. It serves as a buffer against wave erosion during storms.
Foreshore: The area of the beach that is exposed during low tide and submerged during high tide. It experiences constant wave action and erosion.
Backshore: The upper portion of the beach that is only submerged during extreme high tides or storm surges. It is usually dry and subject to wind-driven processes.
What causes waves? As waves approach a shoreline, they ‘break’. Why?
Waves are primarily caused by the transfer of energy from the wind to the water’s surface. As wind blows across the ocean, it creates ripples that develop into waves. As waves approach the shoreline, they begin to feel the ocean bottom, causing the wave crests to become steeper and eventually break. Wave breaking occurs when the wave height exceeds the depth of the water, causing the wave to collapse and release its energy.
What causes tides? What is the difference between neap and spring tides? What causes the so-called “King tide” ?
Tides are primarily caused by the gravitational pull of the Moon and, to a lesser extent, the Sun, on Earth’s oceans. Neap tides occur when the gravitational forces of the Sun and Moon are perpendicular to each other, resulting in lower high tides and higher low tides. Spring tides occur when the gravitational forces of the Sun and Moon are aligned, resulting in higher high tides and lower low tides. King tides, also known as perigean spring tides, occur when the Moon is at its closest point to Earth (perigee), amplifying the gravitational pull and causing especially high tides.
How do longshore currents impact shorelines? What is littoral drift?
Longshore currents are currents that flow parallel to the shoreline, transporting sediment along the coast. Littoral drift is the movement of sediment along the shoreline due to the combined action of waves and currents. Longshore currents and littoral drift can impact shorelines by redistributing sediment, shaping beaches, and forming coastal landforms such as spits and barrier islands.
What is a storm surge and what are its components?
Wind Setup: The increase in sea level caused by strong onshore winds pushing water towards the shore.
Barometric Pressure Drop: The decrease in atmospheric pressure associated with the storm, causing water to pile up.
Wave Setup: The increase in sea level caused by large waves riding on top of the storm surge.
What is a wave cut platform? How does it form?
A wave cut platform is a gently sloping, flat surface eroded by wave action at the base of a cliff or headland. It forms through a process of abrasion and hydraulic action, where waves undercut and erode the base of the cliff, causing it to retreat inland. Over time, the exposed bedrock is worn down into a flat platform by continued wave action.
Why do drowned valleys form?
Drowned valleys form when sea level rises or land subsides, flooding river valleys that were previously exposed. As sea level rises, river valleys are inundated with seawater, forming estuaries or drowned river mouths. This process can be accelerated by factors such as glacial melting or tectonic activity.
Name and describe two methods of coastal stabilization.
Beach Nourishment: Adding sand or sediment to eroded beaches to widen the shoreline and protect coastal structures.
Seawalls and Revetments: Hard structures built along the shoreline to deflect wave energy and prevent erosion of the coast.
Dune Restoration: Planting vegetation and building dunes to stabilize shorelines, absorb wave energy, and protect inland areas from storm surges.
How does wave refraction work to erode points of land jutting out into the sea?
Wave refraction occurs when waves approach a coastline at an angle, causing them to bend and concentrate their energy on headlands or points of land jutting out into the sea. This concentrated wave energy accelerates erosion on the sides of headlands, forming sea cliffs, sea caves, and other erosional landforms.
Briefly describe the fate of the Hampton Beach community under the climate scenario coinciding with net
zero by 2050?
Under a climate scenario coinciding with net zero emissions by 2050, Hampton Beach may experience reduced risks of coastal erosion and flooding due to decreased sea level rise and storm intensity. However, the community may still face challenges related to sea level rise, increased temperatures, and changes in precipitation patterns, necessitating adaptation measures such as shoreline protection, flood defenses, and infrastructure improvements.
