East Yorkshire coastal erosion

The glossary is intended to bring consistency of reference to an ongoing study of East Yorkshire coastal erosion.

Usage of terms tends to be specific to requirements. Broader or alternative meanings may apply in other sources.

Terms that are regarded perhaps as more specialised are entered at glossary plus

accretion

Sustained deposition of beach sediment. Another word might be accumulation. See terminal groyne effect.

across

Used when a feature in the cliff face can be seen within, and to extend either side of, another – e.g. sand bed across a cavity.

backwash

The return, under gravity, of water to the sea after waves break on a beach. Associated action is swash.

band

A distinctive bed of some thickness in the cliff face. A well-known example is the red band.

base of cliff

See cliff base.

bay

Used only for the larger scale, e.g. Bridlington Bay.

baylet

A very small bay. Rarely used.

beach

Area between cliff and sea. Preferred to ‘shore’. Except for photograph captions, where the visible beach is determined according to the state of the tide, the sense extends to the low water mark. As a guide, maximum beach width (cross-beach distance) in much of the study area may be taken to be about 185 metres.

Upper beach. Nearest the cliff. Sloped, sometimes markedly so. Can be expected to vary at any one location and over a relatively short period in terms of width, in thickness and type of sediment cover. Abbreviated to ‘u/b’ in notes.

Transition. A change from upper beach to lower beach, often abrupt, sometimes more a line than a zone. Colloquially known as the grope of the beach. Abbreviated to ‘trsn(.)’ in notes.

Middle beach. The phrase may be used where transition is indistinct. Abbreviated to ‘m/b’ in notes.

Lower beach. From transition to the sea. Extensive at low tide. Typically covered by a thin film of water except for raised areas of sand such as bars. Abbreviated to ‘l/b’ in notes.

beach line

Localised course of the cliff foot.

beach profile

Section across the beach, including the cliff. A beach profile corresponds to a cliff loss monitoring profile. [more]

bed

A thickness, less than a band but greater than a layer, of material deposited at some stage in the deposition of the till or during glacial retreat.

berm

[text]

blocky

Refers to recently separated pieces of the cliff face that may be of some size – e.g. a blocky fall.

boulder clay

See till.

break

General term covering detachment and separation. More distinct than a crack.

breakwater

Another term for groyne. Rarely used.

buttress

A natural cliff feature having a protruding angular aspect that makes it look like a support. May be formed when a slide-smoothed section has itself slipped.

cave

Cavity of large dimensions, in particular depth.

cavity

A hollow of any size in the cliff face.

Collapsed cavity. Caused by failure of overlying material, which is present.

Fall cavity. Caused by a fall from the cliff face of material, which is present.

Open cavity. A cavity largely or wholly cleared of material.

Shallow cavity. An open cavity of relatively little depth.

Slump cavity. Caused by a semi-fluid flow of material, typically after a wet period.

cliff

Used in the singular when part of a specific reference.

cliffs

General term denoting the drop from land to beach (or rise from beach to land), offering for present purposes a longitudinal cross-section through the glacial tills of the East Riding of Yorkshire.

cliff base

The lowest part of a cliff face. Has more of an association with the beach than does the term cliff foot – e.g. cavities are found at the cliff foot, platforms extend from the cliff base.

cliff edge

A point on the cliff top, or a short length of cliff top, where the land surface ends and the cliff descends. This definition is considered to be valid even when a separation crack exists inward of the edge, provided no change in ground level has occurred.

cliff face

A section of cliff as visible from its head to its foot. May be divided as upper cliff, middle cliff, and lower cliff as appropriate. May be abbreviated to ‘u/c’, ‘m/c’, ‘l/c’ in field notes.

cliff head

A near vertical upper cliff which, unlike a headscarp, is clear of material.

The lowest visible part of a cliff face. Not so much association with the beach as is the term cliff base – e.g. platforms extend from the cliff base, cavities are found at the cliff foot.

cliff height

Altitude of the cliff top above Ordnance Datum (not height from the beach).

cliff line

Localised course of the cliff edge. Distinct from coastline. See cliff lines.

cliff setback

Cliff recession in relation to a coastal feature such as defences. See first diagram on the terminal groyne effect page.

cliff slope

The inclination of a cliff face. [text]

cliff toe

Short extension of material on to the beach at the lowest part of a cliff. Other sources may use the term more in the sense of the foot of the cliff.

(cliff) toe horn

A small and upwardly tapering protrusion at or near the end of a cliff toe.

cliff top

The land at, and a short distance behind, the cliff edge. Refers to an area rather than position or line.

parts of cliff

[to prepare: a graphic or annotated image]

coast

Where land meets sea. Includes cliff and beach. Used in a general sense.

coastal erosion

Technically means the removal from the coastal system – cliff and beach – of a volume of material (measured in cubic metres and tonnes) but used synonymously with retreat or recession at the cliff top (cliff loss, landward from the edge, measured in metres), and as a broad term for processes.

coastline

The course of the zone where land meets sea. Used in a general sense and is distinct from cliff line.

collapse

General term for the result of a loss of support of cliff material causing disintegration.

context

When applied to a photograph, it means purposely taken a distance from the subject.

coordinates

Sometimes spelt co-ordinates. See coordinates spreadsheet.

crack

Finer than a break.

crenulate

See terminal groyne effect.

cross-beach

In the general direction from cliff to sea. For a more specific positioning, such as a groyne, the term cliff-perpendicular may be used.

cusp

Beach or swash cusp.

debris

Refers to fragments of concrete, metal, wood – essentially, anything man-made. Not used in the standard geological sense of broken rock.

deposit

[text]

descending

Applies to anything on the cliff face that is dislodged and lower than its original position.

desiccation

The drying out and subsequent shrinkage of the cliff environment, especially after saturation, expressed by extensive cracking and breaking.

detachment

A partial breaking away of a piece from the cliff, normally at the top, but which has not dropped.

differential erosion

Uneven rates of removal because of a change in type of cliff material, such as at a till (unit) boundary.

diffraction

The bending of a wave path as it approaches the beach or round an obstacle.

downdrift

Further south (for the East Yorshire coast) of something or a location, usually in the context of beach movement. Associated term is updrift.

drawdown

Lowering of beach level, usually after a storm. (Rarely used.)

dunes

Specific references in these pages are to dunes south of Bridlington and the Easington Dunes.

edge of cliff

See cliff edge.

embayment

Formation of a bay. Used in connection with the terminal groyne effect.

erosion

See coastal erosion.

erratic

A rock transported by glacial action. May be of any size and origin.

ERYC (East Riding of Yorkshire Council)

Local authority responsible for monitoring rates of erosion along the glacially deposited coast. See Coastal change in the East Riding.

exfoliation

Process by which the desiccated surface of a cliff face begins to break off in layers.

face of cliff

See cliff face.

failure

General term for any reductive change from original situation. Sometimes used synonymously with collapse.

fall

Material that has clearly dislodged, under gravity, from its original position. May be blocky, flaky, loose, slabby, mixed, and wet (though not to be confused with a wet slump or flow).

finger

A vertical slender separated piece still connected by its base to the cliff. May be at the cliff top or descending.

fluting

[text] [cf. rilling]

foot of cliff

See cliff foot.

full height

Extending the entire cliff face, from beach to land (assumes no slips or slides).

gabion

Wire or steel cage-like retaining assembly for rocks as a defence against erosion.

geomorphology

Branch of geology dealing with changes in topographical features and forms.

The present study, which might be called glacial soft cliff geomorphology, observes and aspires to describe causes and processes of local coastal erosion from changes both in the cliffs and to the beach.

gleying

Grey-blue patches sometimes seen on surfaces of exposed cliff.

Air in pores within the clay is replaced by water. Ferrous iron becomes ferric iron which is soluble. Removal of the iron causes a change in colour.

greenery

Informal alternative to vegetation. [Rarely used.]

grope

Colloquial term for beach transition. See beach.

groyne

A structure of timber (also known as a breakwater) or rock extending from the cliff or seawall towards the low water mark in order to retain sediment. See terminal groyne effect.

groundwater

Water originating from rainfall on the land.

gutter runnel

A runnel that forms at the base of the cliff.

head of cliff

See cliff head.

headscarp

The near-vertical surface resulting from a slide at the upper cliff. The dropped section is still present.

Holderness

As regards the coast, Holderness is properly that part of the East Riding of Yorkshire which stretches from Skirlington to Spurn. It does not include the distance from Sewerby to Skipsea. However, for convenience, general references to the Holderness coast tend also to include both stretches.

hotspot

See hotspots page.

hydraulic action

Breaking waves compress the air in cracks, deep cavities, and caves causing a sudden increase in internal pressure which can weaken the surrounding clay.

imbrasion

Refers to a surface that is very slightly concave, less so than a shallow cavity, following the removal of material at the lower cliff.

indentation

Retreat of a length of cliff line between two points, usually protrusions such as spurs. A series of indentations that are similar may be referred to as a serrated configuration. Sometimes abbreviated to ‘indent.’ in notes when referring to examples, e.g. a broad but shallow indent.

in situ

Not having been positionally disturbed in any way by geological processes.

intertidal

Pertaining to the beach between high and low water lines. Anything situated in the intertidal zone will be surrounded or covered by seawater twice a day.

jut

Semi-colloquial term for a small projection of the cliff line, often coming to a point but may be rectangular. Such a feature is commonly found between two indentations.

the land

All that exists behind the cliff line.

lateral

Sideways, e.g. lateral break.

layer

Thinner than a bed.

lens

A deposit within the clay of limited extent – e.g. sand lens.

LiDAR

Light detection and range.

littoral

A term subject to some confusion as it depends on context. The self-explanatory intertidal is preferred.

longshore drift

Movement of sediment by tides in the direction of the sea current. See terminal groyne effect.

low water line

A loose term for where the waves are breaking at or around low tide – e.g. the picture was taken from the low water line.

low water mark

The average position or level where waves break at low tide. Not as specific as MLWM.

lower beach

See beach.

material

Refers by default to clay (till) of any component size or circumstance but is also used in connection with beach deposits and in other specified contexts.

member

Subdivision of a geological formation – e.g. Skipsea Till is a member of the Holderness Formation. A member may in turn be subdivided into units.

MHWM

Stands for Mean High Water Mark. Technically, the average position or level where waves break at high tide taken over a year, excluding storm surges. In practice, high tides wash against the cliff at least some of the time. Associated term is MLWM (Mean Low Water Mark).

migration

Gradual movement in a general direction. In the case of the study area, this is southerly (actually, south-easterly for much of the coast). The term is used in connection with beach features such as ords, and cliff top erosion, especially hotspots.

milling

An increased wearing away of the cliff by pebbles and stones agitated by wave action. Examples are found in undercuts and cavities.

MLWM

Stands for Mean Low Water Mark. The average position or level where waves break at low tide taken over a year, excluding storm surges. Associated term is MHWM (Mean High Water Mark).

monitoring

Refers principally to regular measurement of cliff loss. See measurement and profiles.

mudball

See mudballs.

mudflow

A run of rain-saturated clay in an almost fluid state.

neap tide

Minimum range between consecutive high and low tides. Associated term is spring tide.

OD (Ordnance Datum)

A reference level, set by Ordnance Survey, from which to measure altitude. Used for cliff heights and beach contour levels.

ord

Short for ord system which includes a ridge of sediment and a runnel. Ords, observed to migrate southward at an average rate of about half a kilometre per year, are considered to increase local erosion. See beach movement.

OS (Ordnace Survey)

Ordnance Survey is Great Britain’s mapping authority responsible for the National Grid reference system, as used within this study. OS, XY and Lat/Long values for monitoring profiles are available side by side from the coordinates spreadsheet.

out-eroded

Refers to something once buried in the land surface and now exposed at the cliff as a result of erosion.

outwash channel

Site at the upper cliff of a filled-in channel produced by meltwater during glacial retreat.

overslump

The covering of part of the lower cliff by a slide or slump of different material from higher up in the series – e.g. Withernsea Till is often seen to overslump Skipsea Till at locations where both tills are deposited.

piece

Unless contextually specific, refers to a small to medium mass of clay that is loose from the cliff but remains part of the overall picture.

pillbox

See pillboxes.

pinnacle

A prominent and typically slender piece descending the cliff in a generally upright position, although perhaps having a backwards tilt because of rotational slide influence. Often tapers to a tip but a capped pinnacle retains a flat crown, once a fragment of land surface, usually with vegetation.

planform

The outline of the coastline as viewed from above. Relates to maps and aerial photographs. Rarely used.

platform

Continuation of till from the cliff base. The platform extends under the beach and out to sea. At times of high local erosion, the platform becomes exposed at the upper beach, and occasionally at middle and even lower beach.

In fact, the platform represents the wave-cut surface of a deposit of till which may continue some thirty metres or more down to the chalk bedrock.

platform step

The eroded edge of an exposed section of platform.

pool

A shallow though possibly extensive stretch of seawater anywhere on the beach left by the last high tide.

profile

1. Monitoring profile for the measurement of loss at the cliff top. Abbreviated to ‘Pr’ in notes and on maps – e.g. Pr62.

2. Beach profile.

projection

promontory

Used in a restrictive sense to refer to a full height protrusion from the cliff face (less than full height would be a spur).

recession

Landward movement of the cliff line (and beach line). Also known as cliff loss or retreat.

red band

[description]

refraction

[text]

removal

Refers essentially to the dislodgement and carrying away of material by wave action.

revetment

[text]

rilling

Grooves, usually vertical, cut in the lower cliff by seawater runoff.

rip-rap

See rock armour, the preferred term.

rock-armour

A form of sea defence made up of boulders, also called rip-rap. See examples.

rotational slide

See cliffs - rotational slides.

runnel

Channel of seawater between a bar of sediment and the cliff, often as part of an ord.

sand brow

Raised area of sand on the lower beach, having a more pronounced contour than a sand bar.

sand step

A step-like break in level of the sand surface as a result of beach erosion.

scarp

The area in the vertical plane created when one part of the cliff face slides with respect to another. Sometimes called headscarp when at the upper cliff.

seawall

Extensive vertical or sloping defence structure of solid construction usually aligned with the cliff line.

section

A part of the cliff or beach specific to the observation being made.

sediment

Beach material of any size transported and deposited by the sea.

Although sediment may be formally classified according to particle size, the following range serves most descriptive purposes: large boulder (rare), boulder, cobble, pebble, gravel, shingle (often used as a general term), coarse sand, sand (in general).

sediment body

See beach movement.

sediment compartment

Area between breakwaters.

seepage line

Line marking the emergence of groundwater between a higher unit of till and the one below.

separation

A breaking away of a piece anywhere from the cliff face. Distinct from detachment (partial separation) though is sometimes used instead.

separation crack

Found at the cliff top and signals a potential slide.

serration

Describes how a length of the cliff line breaks to a repeated pattern of indentations.

setback

Cliff recession in relation to a coastal feature such as defences. See terminal groyne effect.

shelf

A platform-like protrusion of a till unit in the cliff face as a result of differential erosion.

shingle

Beach deposit made up mostly of pebbles and small cobbles but may include other sizes of sediment.

shore

An alternative to beach. [Rarely used.]

silt

Very fine-grained material deposited as layers or beds in the clay during glacial melting.

skerrie

Also spelt skerry. Cluster of stones at middle beach transition.

slide

The movement down a cliff of a section of separated material under gravity, more or less as one body. See also rotational slide. Distinct from slump, where deformation takes place.

slide path

Relatively smooth track left by cliff material or an object descending the cliff.

slip

A slip is a small downward movement of material, as of a slide. Slippage refers to the action.

slump

The movement down a cliff of a section or sections of separated material under gravity, where the mass of material loses shape. Distinct from slide, in which the material proceeds more or less as one body.

SMP (Shoreline Management Plan)

See SMPs and profiles.

snout

Projection of slumped material from the lower cliff on to the beach.

spring tide

Maximum range between consecutive high and low tides. The gravitation pull of the sun aligns with that of the moon. Associated term is neap tide. (The term is often erroneously connected with the season. When it refers to a tide, think of spring as a sudden move forward.)

spur

A ridge extending down the cliff face between indentations. A true spur is the full height of the cliff. Slippage produces lesser spurs.

Shoulder spur. A little less than full height, starting at the upper cliff.

Waist spur. Roughly half the total height of the cliff, starting at the middle cliff. A spur starting at the lower cliff may be regarded as a snout.

Hanging spur. Loss of underlying material to produce an overhang.

Razor spur. Also serrated, spiny or saw-tooth(ed) spur. Any spur having a sharply defined crest, usually ragged.

Truncated spur. Any spur with forward material removed.

storm surge

Caused by a temporary rise in sea level due to winds but also atmospheric low pressure. Water is piled against the coast and may result in flooding on low land, especially when the surge occurs in conjunction with a high spring tide.

strand line

A mark left on the upper beach by the last high tide. Strand lines from earlier tides may also be present.

stringer

A thin and discontinuous exposure in the cliff face of glacially crushed and spread rock, nearly always chalk.

structure

As in a specific structure. By default, something man-made. Usually refers to sea defences or (remains of) wartime installations – e.g. a pillbox.

sub...

As applied to deposits.

Subaerial. Above water level.

Subacqueous. Below water level.

Subglacial. Below glacial ice (cf. englacial: within a glacier, and supraglacial: on the surface of a glacier).

swash

Forward movement of wave action up a beach. Associated action is backwash.

TGE (terminal groyne effect)

See the terminal groyne effect page for an explanation and examples of the process. A section of the coast where the effect is apparent may sometimes be referred to as a TGE.

tides

Falling tide. Also ebb tide. The sea is going out.

Rising tide. Also flood tide. The sea is coming in.

High tide. [text]

Low tide. [text]

Slack (water). Tide turn.

See also neap tide and spring tide.

The tide along the East Yorkshire coast turns about every twelve-and-a-half hours or so, and at a slightly later time the further south the location.

till

Unsorted material deposited directly by glacial ice. Once known as boulder clay. See till types and glaciations and tills.

top of cliff

See cliff top.

topple

Describes the falling over, usually towards or on to the beach, of a piece such as a finger.

truncated

Removal of the seaward part of something by wave action or cliff loss – e.g. truncated spur, truncated land drain.

undercut

A length of lower cliff that has been eroded by wave action leaving an overhang. Often expressed as a notch but may be much more emphasised.

unit

A specific grouping of beds or layers within a till member, but may also refer to an individual bed or layer.

updrift

Further north (for the East Yorshire coast) of something or a location in the context of currents and tides. Associated term is downdrift.

upper beach

See beach.

varves

Normally referred to in the plural. Laminations of (usually) silt within a layer or bed of like sediment denoting annual or regular deposition during glacial melting.

vegetation

Grass, and other growth – e.g. bushes.

void

A cavity, especially one left by something such as an erratic or man-made object that has fallen out of the cliff. [Rarely used.]

water cut

A narrow, sometimes deep, vertical incision in the cliff face resulting from a prolonged single source of groundwater, such as a truncated land drain.

water line

[text]

water table

Upper surface of groundwater, below which the soil is saturated.

wet slump

A viscous slump caused by the burden of water after heavy rain. More massive and less mobile than a mudflow.

If you would like to suggest an amendment or correction to the contents of this glossary page, please contact.

Pictures and text by Brian Williams unless otherwise stated.