Coasts EQ 3 Flashcards
why is it that coastal areas are dynamic?
However, coastal areas are dynamic environments that are easily affected by natural changes and the pressures from human activities.
define sustainable management:)
management strategies that meet the needs of the present without
compromising the ability of future generations to meet their own needs.
Talk about limiting damaging activities!
- Human activities can harm coastal environments.
- Examples include blasting coral reefs, clearing mangroves, and building docks and marinas.
- These actions disrupt natural systems and change coastal processes.
- Economic factors make it expensive and inefficient to ban these activities.
- Governments often manage these activities to balance economic interests with environmental protection.
what does Management of a coastal area means? and what does it involve?
Management of a coastal area means controlling the development and change in the coastal zone according to agreed principles and criteria. This involves:
1. implementing policies
2. enforcing them using one or more strategies.
what are the two areas of management to consider?
- Using laws and regulations
-to limit damaging activities,
-to protect coastal resources,
-to restrict development in areas prone to natural hazards. - Using coastal protection measures (hard and soft engineering).
give me examples of limiting damaging activities strategies!
Protecting coastal resources is a management strategy that aims to…
prevent resources from being exploited
or depleted.
What are some protect coastal resources strategies? There are 2
- Marine Protected Areas (MPAs)
- Promoting sustainable fishing practices
what are some Restrict development in areas prone to natural hazards strategies? There are 3.
- Retreat, or relocation of built structures away from areas prone to natural hazards
- defence, such as nourishing beaches, building seawalls and replanting coastal vegetation
- avoidance, which involves regulating development to avoid key areas that are prone to natural hazards.
Talk about Restrict development in areas prone to natural hazards
- Natural hazards like tsunamis can severely impact coastal areas.
- People are drawn to coasts for resources and services.
- Governments develop policies to manage these hazards through research, planning, and enforcement.
What is hard engineering?
- Construction of physical structures to protect coasts from wave erosion.
- Structures include seawalls, gabions, breakwaters, and groynes.
- More commonly used than soft engineering measures.
What are the 5 hard engineering methods?
- gabions
- groynes
- tetrapods
- seawalls
- breakwaters
What does soft engineering method mean?
- Protecting the coast using natural processes.
- No physical structures involved.
Seawalls aim
- Seawalls are constructed to protect coastlines against wave attack by absorbing wave energy.
- Made of concrete or stone, built parallel to the coast.
what are the 3 soft engineering methods
- beach nourishment
- replanting coastal vegetation
- encouraging coral reef growth
Seawalls strengths!
- Defends against flooding and erosion.
- Stabilizes adjacent beach sand.
- Easy to construct, lasts 30-40 years.
- Used worldwide.
Seawalls weaknesses
- Expensive to build and maintain.
- Requires frequent repairs to prevent collapse.
- Reflects waves, causing beach erosion. The powerful backwash of reflected waves washes away the beach materials at the foot of and beneath the seawall.
- Erosion under the base can lead to collapse.
Gabions aim
Gabions are wire cages usually filled with crushed rocks. These cages are built along a shore or behind a
beach to prevent or reduce coastal erosion by weakening wave energy.
gabions strengths
- Absorb wave energy well This is because the gaps between the rocks allow water to filter through. This way gabions prove to be successful defences against high energy waves..
- Quick to construct, reducing erosion.
- Cheaper and less damage control needed from erosion
gabions weaknesses
1.Corrode easily, need frequent maintenance.
2. Prone to damage, hazardous when rusted.
3. Visually unappealing.
Breakwaters strengths
- Create calm water zones behind the. sediments are then deposited in calm zone for beach formation and sheltered harbours.
- Can last up to 30 years.
Breakwaters weaknesses
- Expensive to build.
- Provide uneven protection; only shield areas behind them.
- Areas away from breakwaters can still erode.
- Visually unappealing.
Breakwaters aims
- reduce the force of incoming waves before they reach the coast.
- usually made of granite.
Two types:
1. parallel to the coast
2. one end attached to the coast.
Groynes aim
Retain sediments and prevent erosion caused by longshore drift.
Groynes weaknesses
- Downdrift side erodes due to lack of new sediment.
- Costs are high for construction and maintenance.
- Considered unsightly.
Groynes strengths
- Absorb wave energy and deposit materials on the updrift side.
- Build and widen beaches, provide calm water.
- Can last up to 30 years.
Tetrapods aim
- Dissipate wave energy using four-pronged concrete structures.
- Stacked offshore in an interlocking position.
Tetrapods strengths
- tetrapods allow water to pass around them rather than hit against them -> no powerful backwash is generated -> reduces the possibility of tetrapods being damaged
by waves. - Pre-casted and quick to place.
- Effective against coastal erosion and tsunamis.
Tetrapods weaknesses
- High construction cost.
- Visually unappealing.
- Hazardous to swimmers, surfers, and boaters.
Beach nourishment aims
Slow down beach erosion by replenishing sand from external sources.
Beach nourishment strengths
- Creates wide, natural-looking beaches.
- Does not alter local biodiversity.
Beach nourishment weaknesses
- Expensive and time-consuming.
- Sand can wash out and harm marine environments.
- Short-term solution; requires frequent replenishment.
Planting vegetation and stabilising dunes strengths
- Relatively inexpensive.
- Absorb wave energy and reduce erosion.
- Improve water quality and support marine ecosystems.
Planting vegetation and stabilising dunes weaknesses
- Takes years to establish and become effective.
- Not suitable for all coastal areas, especially those with violent waves.
- Requires specific climatic conditions.
Planting vegetation and stabilising dunes aims
Stabilise coastlines by planting vegetation such as mangroves.
Encouraging coral reef growth strengths
- Enhance beach aesthetics.
- Support diverse marine life.
Encouraging coral reef growth aims
Weaken wave energy and provide habitat by creating artificial coral reefs.
Encouraging coral reef growth weaknesses
- Coral growth is challenging and requires site surveys for optimal conditions.
- Reefs are sensitive to water quality and temperature changes.
- Specific water conditions are essential for coral growth.
- Not all coastal environments are suitable for coral reefs.
- Coral growth is slow, often taking 20-30 years to show significant results.
