Podcast
Questions and Answers
What characterizes an erosional coast?
What characterizes an erosional coast?
- High sediment accumulation
- Low-wave energy
- Net sediment loss (correct)
- Presence of beaches (correct)
What is a key feature of a depositionional coast?
What is a key feature of a depositionional coast?
- High wave energy
- High-energy environment
- Net sediment loss
- Net sediment accumulation (correct)
What type of environment are the present shorelines of the world considered to be?
What type of environment are the present shorelines of the world considered to be?
A dynamic environment affected by both long-term and short-term cycles.
How much has the world sea level varied over the past 2 million years?
How much has the world sea level varied over the past 2 million years?
What is the origin of sea cliffs, sea stacks, sea caves, blowholes, and arches?
What is the origin of sea cliffs, sea stacks, sea caves, blowholes, and arches?
Where are steep, narrow, rocky beaches typically found?
Where are steep, narrow, rocky beaches typically found?
What drives longshore currents?
What drives longshore currents?
How do oceanographers usually classify coasts?
How do oceanographers usually classify coasts?
What is a common problem facing many beaches along the U.S. east and west coasts?
What is a common problem facing many beaches along the U.S. east and west coasts?
What is an estuary formed where a rapidly flowing large river enters the ocean in a low to moderate tidal range called?
What is an estuary formed where a rapidly flowing large river enters the ocean in a low to moderate tidal range called?
An estuary is a type of delta.
An estuary is a type of delta.
Give an example of a partially mixed estuary.
Give an example of a partially mixed estuary.
What does refraction do over time?
What does refraction do over time?
What does a longshore current do?
What does a longshore current do?
What impacts longshore drift?
What impacts longshore drift?
What is the result of longshore drift moving sediment down the beach?
What is the result of longshore drift moving sediment down the beach?
What defines a beach?
What defines a beach?
Study Notes
Coastal Types
- Erosional Coast: Characterized by net sediment loss, high-energy environment with significant wave activity; typically has beaches.
- Depositionional Coast: Defined by net sediment accumulation, often found in lower-energy environments.
Shoreline Dynamics
- Present Shorelines: Dynamic environments influenced by long-term and short-term cycles of change.
- Sea Level Variability: Over the past 2 million years, sea level has fluctuated between approximately 6 meters above and 125 meters below current levels.
Coastal Geomorphology
- Formation of Coastal Features: Sea cliffs, sea stacks, sea caves, blowholes, and arches are shaped primarily by wave erosion.
- Rocky Beaches: Steep, narrow, rocky beaches are typically situated in areas with high wave energy.
Coastal Currents and Processes
- Longshore Currents: Driven by wind waves that approach the coastline at an angle, these currents play a vital role in sediment transport along the coast.
- Classification of Coasts: Oceanographers categorize coasts based on the physical processes that shape them.
Beach Erosion Issues
- U.S. Beach Problems: Both east and west coasts of the U.S. face significant challenges from sand loss and beach erosion.
Estuary Types
- Salt Wedge Estuary: Forms where large, rapidly flowing rivers meet the ocean in low to moderate tidal ranges.
- False Statement about Estuaries: Estuaries are not classified as a type of delta.
- Partially Mixed Estuary Example: Chesapeake Bay is identified as a partially mixed estuary.
Coastal Processes and Sediment Movement
- Refraction: A process that erodes headlands over time by bending wave energy.
- Longshore Current: Responsible for lateral distribution of sand along the shoreline.
- Longshore Drift: Influenced by human structures; crucial for sediment transportation along the coast.
Effects of Longshore Drift
- Sediment Movement: Longshore drift results in beach growth on the updrift side, while erosion occurs on the downdrift side, often requiring multiple groins for management.
Beach Definition
- Beach Characteristics: Composed of loose particles covering part or all of a shore, with limits defined by sediment movement; includes an upper limit (formed by dunes, seawalls, cliffs, or vegetation) and a lower limit at a depth of about 10m where onshore sediment transport ceases, constantly changing due to environmental factors.
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