Glossary

Apparent Cohesion

The resistance to soil particles separating from one another which is independent of soil particle forces.

Backshore

The portion of the shoreline located landward of the berm crest, only wetted in very high tides or storms, technically between "ordinary high water" and the highest water line.

Bank

The rising ground bordering the sea, a river, or lake. Also see BLUFF and CLIFF

Beach

The zone of unconsolidated material that extends landward from the low water line to the place where there is marked change in material or physiographic form, or to the line of permanent vegetation (usually the effective limit of storm waves). The seaward limit of a beach is the extreme low water line. A beach includes FORESHORE and BACKSHORE.

Bearing Capacity

The load per unit area which the ground can safely support without excessive deformation.

Bedrock

A general term for the rock, usually solid, that underlies soil or other unconsolidated, surficial material.

Bioengineering

In soil applications, refers to the use of live plants and plant parts to reinforce soil, serve as water drains, act as erosion prevention barriers, and promote dewatering of water laden soils.

Biotechnical

In slope stability engineering, refers to the use of both live plant material and inert structures to stabilize and reinforce slopes.

Bluff

An unvegetated high bank composed largely of unconsolidated deposits with a near-vertical face overlooking a body of water.

Bluff Crest

Upper edge or margin of a shoreline bluff.

Bluff Face

The sloping portion of a high bank.

Bluff Toe

The base of a bluff where it meets the beach.

Buffer

A protective strip of vegetated land.

Back to top

Clear-Cut

A timber harvest method which removes all the trees on an area in one operation.

Cliff

A high, very steep to perpendicular or overhanging face of rock rising above the shore.

Coastal Zone

The sea-land fringe area bordering the SHORELINE where to coastal waters and adjacent lands exert a measurable influence on each other.

Cohesion

The internal resistance of individual soil particles to separate from one another.

Competence

  1. In hydrology the ability of a current of water or wind to transport particles, emphasizing the particle size rather than the amount, measured as the diameter of the largest particle transported.
  2. In structural geology a sediment or rock layer, rigid and strong enough to transmit the thrust of flooding by lateral compression and capable of sustaining the weight of overlying strata or man-made structures without losing its structural integrity when arched or exposed to loading.

Deciduous

Losing leaves or needles in the fall.

Drainage (soil)

The rapidity and extent of the removal of water from the soil by surface runoff and by down-draw flow through the soil. Also, the natural and artificial means for improving this removal by a system of surface and subsurface conduits.

Earthquake

A sudden motion or trembling in the Earth caused by the abrupt release of slowly accumulated strain (by faulting or by volcanic activity).

Erosion

The wearing away of rock or soil and the movement of the resulting particles by wind, water, ice, or gravity, but usually excluding MASS MOVEMENTS.

Evergreen

A plant which retains its needles or leaves for more than one growing season.

Extreme High Water (EHW)

The average height of the highest tidal waters reached during the year over a 19-year period.

Back to top

Feeder Bluff

An eroding shoreline bluff which supplies material to accreting shorelines.

Flow

A MASS MOVEMENT involving rapid flowage of wet soil, rock, and displaced vegetation as a viscous mass down a slope or a channel; including mudflow, debris flow, and earthflow.

Foreshore

The lowest segment of a beach, between lowest tide and the berm crest, covered by most daily tides, technically between the "lowest low water" line and the "ordinary high water" line.

Formation - (geologic)

The ordinary unit of geologic mapping recognized by field criteria consisting of a larger, persistent, and mappable strata of predominantly one kind of rock or sediment type.

Geotechnical

Refers to the application of civil engineering technology to some aspect of the earth.

Geotechnical Structures

Along coastal slopes, refers to slope protection designs such as retaining wall, revetments, and designed slope recontouring.

Gully

Large intermittent drainage channel developed from the erosion forces of drainages occuring from surface water runoff.

Hardpan

A hard, impervious, often "clayey" layer of SOIL lying just below the surface. Sometimes synonymous for TILL.

Back to top

Impermeable

Having a texture that does not permit fluids to move through it freely.

Infiltration

The movement of water or solutions into or through a rock or soil through its INTERSTICES or fractures; the flow of rain water into soil material.

Inter-dependent

A group of plants which growing together protect each individual from disturbance by wind, erosion or other natural processes. Often shallow rooted trees will remain windfirm because they form a wide, spreading root mat.

Interstices

Openings or spaces in rock or soil that are not occupied by solid matter.

Interstices or fractures

The flow of rain water into soil material.

Joint

A crack (parting or fracture) formed in rock by movements normal to the cracks and without shear movements (by displacement) of the rock on either side of the crack.

Landfill

  1. The solid waste disposal process using land as the final disposal site.
  2. A fill area specifically for the purpose of creating additional dry land, usually accomplished by covering a wet or swampy area or slope face with sand or other suitable material.

Mass Movement

A unit movement of a portion of the land surface down a slope as a SLIDE, a FLOW, or SOIL CREEP in which gravity is the main driving force.

Natural Landscape Elements

The natural watercourses, topography, hydrology and vegetation which comprise a particular site.

Overstory

The portion of a forest that forms the upper crown cover.

Percent Slope

The direct ratio (multiplied by 100) between the vertical and the horizontal distance for a given slope; e.g., a 3-foot rise in a 10-foot horizontal distance would be a 30 percent slope.

Poorly Sorted

Unconsolidated deposits that consist of particles of many sizes mixed together in an unsystematic manner so that no one size fraction predominates.

Back to top

Rill

A tiny drainage channel cut in a slope by the flow of water. Can develop into a gully with continuing erosion.

Runoff

That part of the precipitation that appears in uncontrolled surface streams, drains, or sewers. It is the same as streamflow unaffected by artificial diversion, imports, storage, or other works of man in or on the stream channels.

Saturated

A condition in which the INTERSTICES of a material are filled with a liquid, usually water.

Seismic

Pertaining to earthquakes or earth vibrations, including those that are man-made, e.g., explosions and underground nuclear blasts.

Shear Strength

Resistance to lateral movement or failure along a potential failure surface.

Shoreline

The intersection of a specified plane of water with the BEACH; it migrates with changes of the tide.

Slide

A MASS MOVEMENT resulting from failure of SOIL or rock along a rotational or planar surface.

Slope

The inclination of the land surface from the horizontal percentage of slope is the vertical distance divided by the horizontal distance, then multiplied by 100.

Slump

A SLIDE characterized by a rotary movement of a generally independent mass of rock or earth along a curved slip surface.

Soil

In engineering work a soil is any earthen material, excluding hard bedrock, composed of 1) loosely bound mineral and organic particles, 2) water, and 3) gases. In agriculture, a soil is the loose surface material capable of supporting plant growth, and having properties resulting from the integrated effect of climate and living matter on the decomposition of bedrock and surficial deposits.

Soil Arching

A phenomena that transfers lateral soil pressure to adjacent rigid members (trees, piles, etc.) anchored in an unmoving soil or rock zone.

Soil Creep

The gradual and steady downhill movement of soil and loose rock material on a slope.

Strata

A layer of soil.

Stratigraphic Section

Any sequence of rock units found in a given region (the oldest at the bottom and the youngest at the top).

Back to top

Tablelands

The tops of bluff areas usually developed for homesites.

Tensile Strength

Resistance to rupture or failure due to tensile forces or pulling.

Thinning

Tree removal in a forest stand that reduces tree density and numbers in a given area. Most discussions of thinning stress increased growth and yield of timber.

Till

POORLY SORTED and generally unstratified sediments, deposited directly by and underneath a glacier. Usually very hard and compact, with good bearing capacity and low permeability.

Toe of Slope

See BLUFF TOE.

Unconsolidated

Said of sediment whose particles are loose and not cemented together.

Undercutting

The removal of material at the base of a steep slope or cliff or other exposed rock by the erosive action of waves, running water, or sand-laden wind.

Understory

Trees or other plants which tolerate reduced-light conditions and normally grow beneath the forest canopy.

Upland

A general term for elevated land above the beach which lies above the EXTREME HIGH WATER level.

Wetlands (Biological)

Lands transitional between terrestrial and aquatic systems where the water table is usually at or near the surfaces or the land is covered by shallow water.

Wetlands (Jurisdictional)

Land forms which support under normal conditions a predominance of hydrophytic (wetland) vegetation, hydric (wetland) soil types, and wetland hydrology. Typically, they are jurisdictionally defined as: "Those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions (Federal Interagency Committee for Wetland Delineation, 1989)".

Windthrow

Trees blown over by the wind. Usually caused by THINNING or adjacent clearing.

Back to top