Science Unit 5 Lesson 2 Flashcards
What is beach erosin?
the movement of sand and sediment from off the shore to deeper waters
What does sand erosin do?
Beach erosion causes shorelines to move inland or shift, impacting both the surrounding environment and human activity.
What are some beach erosion management strategies?
- jetties
- groins
- seawall
- coconut coir logs
How are jetties and groins similar?
Jetties and groins are hard structures built perpendicular to the shoreline. They both protect from erosion caused by waves and current.
How are jetties and groin different?
Groins tend to be smaller, shorter structures, whereas jetties can reach farther out into the ocean.
What are the downside of jetties and groins?
While both are viable management options, they can actually cause some erosion in places as sand piles up on the updrift side of the structure, resulting in less sand on the downdrift side.
How to combat the downside of jetties?
Erosion caused by jetties can be severe with unintended consequences for beaches on the downdrift side of the jetty. Because of this, multiple jetties have to be built to help reduce this effect.
What are seawalls?
Seawalls are structures built at the water’s edge or slightly inland. They protect the land from rising tides as well as from strong waves or tsunamis. While seawalls can be expensive to install, they have an additional benefit of flood protection.
How do seawalls work?
As a wave crashes into a seawall, the energy of the wave is reduced, causing it to pick up and erode less sand.
What are cocnut coir logs?
Coconut coir logs are placed along shorelines to help reduce beach erosion.
What are coconut coir logs made out of?
They are round logs made of coconut fibers. They are biodegradable, safe for surrounding wildlife
How do coconut coir logs help sea grass form?
They can help to stabilize the area long enough for natural seagrass to establish a strong root structure. However, this can take time to allow for growth of plant life and may not have immediate results.
Jetties vs seawalls
Jetties: run perpendicular to shoreline, built into the water ,can cause erosion on downdrift side of jetty
Both: hard structures, help reduce beach erosion
Seawalls: built inland, protect against flooding, run paraell
What is beach nourishment?
Beach nourishment involves adding sand and sediment to a beach. Unlike structures that help to keep existing sand and sediment on the shores, beach nourishment replaces what has been lost. It helps to create new natural environments, rebuild sand dunes, and protect sediment volume during sea level rise.
What are some setbacks of beach nourishment?
beach nourishment is a very expensive strategy. It requires the pumping or trucking of sand onto beaches. In some cases, this can cost millions of dollars. It is also not a long-term solution to the problem of erosion.
