Coastal Protection Systems – Vocabulary Review

A set of vocabulary flashcards covering definitions, materials, processes and structural types discussed in the Coastal Protection System lecture.

Coastal Protection System

Any combination of measures—hard or soft—designed to defend shorelines from erosion and flooding.

Coastal Erosion

The process of shoreline retreat caused by wave, current, or storm action removing sediment.

Hard Engineering

Structural, permanent defences such as sea walls, revetments, groynes and breakwaters.

Soft Engineering

Non-structural or flexible measures like beach nourishment, mangrove replanting and geotextile tubes.

Sea Wall

A rigid barrier built parallel to the coast to prevent land loss and flooding by reflecting wave energy.

Revetment

A sloping armour‐rock or concrete layer placed on banks or beaches to absorb and dissipate wave force.

Groynes

Shore-perpendicular structures that trap littoral drift and stabilise beach width.

Breakwater

An offshore or shoreline barrier that creates calm water by reducing incoming wave energy.

Beach Nourishment

Artificial placement of compatible sand on an eroding beach to restore volume and width.

Mangrove Replanting

Soft measure where mangrove seedlings are introduced to stabilise muddy coasts and attenuate waves.

Sediment-filled Geotextile Breakwater

A breakwater made of large, sand-filled geotextile tubes that adapts to soft foundations.

Pressure Equalization Module

Porous devices inserted in beaches to relieve pore-water pressure and slow erosion.

Malaysia Coastline Length

Approximately 4,809 km in total: 2,031 km Peninsular Malaysia, 2,778 km Sabah & Sarawak.

Critical Erosion Area (Category 1)

Coastal reach where immediate engineering action is required to prevent loss (≈200 km in Malaysia).

Significant Erosion Area (Category 2)

Stretch likely to become critical within 5–10 years if left untreated (≈235 km in Malaysia).

Acceptable Erosion Area (Category 3)

Reach with tolerable, naturally adjusting erosion requiring monitoring only (≈955 km in Malaysia).

High Water Line (HWL)

The average position on the shore reached by high tide or storm surge.

Low Water Line (LWL)

Average level of the lowest daily tide marking seaward beach limit.

Wave Base

Water depth below which normal wave motion no longer stirs the seabed sediment.

Storm Wave Base

Greater depth reached by storm-generated waves influencing seabed sediments.

Tsunami Wave

Long-period wave generated by seismic events, able to inundate far inland areas.

Intertidal Area

Zone between HWL and LWL alternately exposed and submerged each tidal cycle.

Cliff Coast

Steep rocky shoreline dominated by wave attack and vertical erosion.

Clayey Bank Coast

Soft cohesive shoreline where fine sediments form low banks and shore platforms.

Intertidal / Muddy Coast

Low-gradient shore with mudflats, saltmarshes or mangroves; highly sensitive to waves.

Sandy Coast

Beach composed mainly of sand grains, shaped by waves and currents.

Armor Rock

Large quarried stones placed on revetments or breakwaters to absorb wave impact.

Steel Pilings

Driven steel sheets or H-piles forming the structural backbone of some sea walls.

Reinforced Concrete

Concrete strengthened with steel rebar; common material for massive seawalls.

Steel Gabions

Wire cages filled with rocks, used as flexible, permeable sea wall or revetment elements.

Vertical Sea Wall

Straight, upright wall reflecting wave energy; suited to deep water close to shore.

Curved (Ogee) Sea Wall

Seawall with concave face that deflects uplift and reduces overtopping.

Massive Block Wall

Sea defence built of large concrete blocks stacked for weight and stability.

Toe Protection

Extra armour or concrete placed at the base of a wall to prevent scour undermining.

Wave-break Pile

Row of driven piles used to reduce wave force before it reaches a structure.

Sheet Pile

Interlocking steel, vinyl or timber sheets forming thin vertical walls for groynes or seawalls.

Bearing Pile

Deep foundation element transferring structural loads to stronger subsoil beneath weak layers.

Flanking Erosion

End-around scour occurring at the unprotected edges of a defence structure.

Scour Apron

Geotextile or rock mat laid around geotubes or walls to resist bed erosion at the base.

Geotube

Large woven-fabric tube hydraulically filled with sand, creating a flexible shoreline barrier.

Scour

Localised removal of seabed or riverbed material by currents or waves, undermining structures.

Beach Replenishment (Feeding)

Synonym for beach nourishment – periodic addition of sediment to maintain beach profiles.

Updrift / Downdrift

Directions relative to longshore sediment transport; updrift is supply side, downdrift is lee side.