Coastal Environments exam 3

Common Rock Types on Cliffed Coasts and Their Relative Strength

Cliff- Steep slope above water (>40°). Not overtopped by waves.

Bluff-Steep slope above water (>40°).Composed of poorly consolidated material(sand/ silt/ clay)

Bank- Steep slope above water (>40°).Commonly overtopped by waves

Cliffed Coast Classification (Plunging, Type A, Type B)

Plunging- cliff face extends below water line, waves break directly against cliff face, usually in resistant bed rock, very slow erosional rates

Type A- most common type, erosion at toe leads to horizontal recession, gentle slope in the intertidal zone to deeper water

Type B- More rapid horizontal recession than vertical erosion at toe, Wave cut platform in intertidal zone

Process of Cliffed Coast Erosion

wave induced erosion

Hydraulic Forces on Sea Cliffs

wave hammer, air compression in fractures and pore space, seismic motion, and shear stress

Biologic Forces on Sea Cliffs

root wedging, gastropods (limpet) - rock scraping, boring organisms, acid dissolution, and chelation

Cliffed Coast Landforms (Stack, Arch, Platform, Cave, Blowhole)

Sea Stake- a geological landform consisting of a steep and often vertical column or columns of rock in the sea near a coast formed by wave erosion

Arch- forms when sea caves merge from opposite sides of a headland

Platform-a gently sloping rock ledge that extends form the high-tide level at the steep-cliff base to below the low-tide level.

Cave- formed primarily from erosion caused by waves and can be formed along the ocean coasts and lakeshores where water impacts bedrock

Blowhole-when sea caves grow towards the land and upwards creating a vertical shaft that exposed on the surface

Why Coastal Engineering is Necessary

threat of sea level rise/shoreline transgression, protects structures (buildings), infrastructures (roads, bridges), economic resources (tourism economies), and environmental management (protection of eroding wetlands)

Common "Hard" Coastal Engineering Structures and Their Function (SeaWall, Breakwater, Groin Field, Jetty)Common "Hard" Coastal Engineering Structures and Their Function (SeaWall, Breakwater, Groin Field, Jetty)

Sea wall- vertical or near vertical shore parallel structures designed to protect property, prevent upland erosion, and storm surge flooding

Break water- an offshore-parallel structure that breaks waves, reducing the energy reaching the beach and fostering sediment accretion between the beach and breakwater

Groin Field- shore-perpendicular structure that inhibits the alongshore movement of sand and "catch" the sand

Jetty- a shore-perpendicular structure that are placed adjacent to tidal inlets and harbors to control inlet migration and minimize sediment deposition within the inlet.

Common "Soft" Coastal Engineering Structures and Their Function (Dune construction, Plating Vegetation, Geotextiles)

Dune construction- act as reservoirs of sand that help the beach maintain its natural equilibrium and preserve the ability of the beach to respond natural to storm events

Plating Vegetation-process of planting vegetation like maritime forest, scrub thickets, grassy upland prairies and marshes which anchors the soil and prevents it from washing out to sea

Geotextiles- porous fabrics used for erosion and sediment control purposes that is designed for filtration, drainage, separation of soil layers, reinforcement, and stabilization

Positive and Negative Effects of Common Coastal Engineering Structures

Positive- reduces and prevents erosion and flooding on shoreline, offer increased safety for residents and visitors, prevents damage to the soils and environment, and reduce effects of storm surge

Negative- blocks the natural drift of sand prevailing along most coast, deprives beach of sand and initiates erosion on downdrift side of structure, expensive, last only a short period of time, and visually unattractive and unsustainable.

Beach Nourishment Methods

dredging material from a source area to feed the beach where erosion is occurring and trucking sand onto the beach

Positive and Negative Effects of Beach Nourishment

Positive- widens the beach, protects structures, protects from storms, grows economy through tourism, encourages vegetation growth, and expands habitat

Negative- added sand may erose, expensive and requires repeated application, destroy/buries marine life, difficult to find appropriate materials

Living Shorelines

the use of plants or other natural elements = sometime sin combination with harder shoreline structures- to stabilize estuarine coasts, bays, and tributaries

Costal Resources - What they are and how they are used

physical marine resources-extraction of energy directly from heat or motion of ocean water (oil, natural gases, wind, wave, and tide)

Biological marine- living plant and animals in the ocean collected for human use (fisheries and aquaculture)

Non extractive- use of the ocean in place without removal of materials (shipping, waste disposal, and tourism/recreation)

Coastal Policy - Mechanisms Governments use to control Coastal Development/Use

jurisdiction, 1953 Submerged Lands Act, Environmental Protection Act (1970), Coastal Zone Management Act, Barrier Resources Act, and Protected Areas Programs

Funding for Protective Structures and Nourishment

Funding for Insurance for Coastal Landowners

Threats to Human Coastal Habitation

extreme natural events like hurricanes, coastal storms, tsunamis, landslides, coastal erosion and sea level rise

Managed Coastal Retreat - Concept and Associated Issues.

Is the strategy of moving infastructure inland instead of defending the coastline

Issues: Property rights, cost, political resistance, social equity, culture and people moving from home.

Funding for Protective Structures & Nourishment

Comes from federal, state, and local governments.

Often requries cost sharing with property owners.

Funding for Insurance for Coastal Landowners

Often provided through the National Flood Insurance which is the (NFIP).

may be subsidized, controversial in high risk areas,

Small portion from private insurers.

Might not get a lot of insurancs for places that flood or get destroyed a lot