Glossary of Terms
The horizontal dimension of the beach measured normal to the shoreline and landward of the high water mark line on coasts.
A permanently fixed point of known elevation. A primary bench mark is one close to a tide station to which the tide staff and tidal datum originally are referenced.
A geomorphological feature usually located at mid-beach and characterized by a sharp break in slope, separating the flatter backshore from the seaward-sloping foreshore.
Rubble mound structure with horizontal berm of armor stones at about sea level, which is allowed to be (re)shaped by the waves.
(Also called biodiversity) - The diversity of life, often divided into three levels: genetic (diversity within species), species (diversity among species), and ecosystem (diversity among ecosystems).
The mass of living matter per unit of habitat (e.g. volume of water or area of bottom). Also referred to as standing crop or standing stock.
a depression on the land surface caused by wind erosion.
Biochemical (or Biological) Oxygen Demand - high figures suggest pollution or eutrophication.
A wave breaking on a shore or over a REEF, etc. Breakers may be classified into four types:
- COLLAPSING--breaking occurs over lower half of wave, with minimal air pocket and usually no splash-up. Bubbles and foam present.
- PLUNGING--crest curls over air pocket; breaking is usually with a crash. Smooth splash-up usually follows.
- SPILLING--bubbles and turbulent water spill down front face of wave. The upper 25 percent of the front face may become vertical before breaking. Breaking generally occurs over quite a distance.
- SURGING--wave peaks up, but bottom rushes forward from under wave, and wave slides up beach face with little or no bubble production. Water surface remains almost plane except where ripples may be produced on the beach face during runback.
The still-water depth at the point where a wave breaks. Also called breaking depth.