Cave System: a natural subterranean cavity produced by slow solution of limestone
or marble. Consist of series of chambers that are large enough for a person to enter
Sinkhole: a surface depression formed by a solution of underlying limestone or by
collapse of a cave
Channel Restoration: the process by which a stream channel is returned to a
Floodplain: the flat land adjacent to a stream produced by overbank flow and
lateral channel migration
River: a large natural stream
Expansive soil: a type of clayey soil that, upon wetting and drying, expands and
contracts, damaging foundations of buildings and other structures
Organic sediment: the in situ accumulation of partially decayed plant material,
mainly peat. Organic sediment is common in swamps, marshes, bogs and fens.
Subsidence: the lowering of Earth’s surface because of sediment compaction, an
earthquake, or other natural process.
Channelization: the modification of a storm channel to permit more efficient
conveyance of water and sediment. Involves straightening, widening and in some
instances, deepening and lining the channel
Floodplain regulation: the government restriction on land use in areas subject to
flooding by streams
Stream: a ribbon-like body of water flowing in a channel; includes brooks, creeks,
Groundwater pumping (mining): the extraction of groundwater at an
unsustainable rate that is faster than water is replenished
Permafrost: rock or sediment that is colder that 0 degrees continuously for at least
two years and contains disseminated or segregated ice. Permafrost underlies about
20% of Earth’s land area including about half of Canada and is commonly of
thousands of meters thick Discharge: the volume of water flowing past a point in a stream channel over a
specific period, typically a second. Discharge is commonly measured in cubic m/sec
Recurrence interval: the time between successive floods, earthquakes, or other
disastrous events. Commonly expressed as average values (in years), based on the
series of events.
Karst: an area of carbonated rock characterized by features produced by dissolution
of calcite ad dolomite, notably fissures, sinkholes and caves. Surface drainage in
karst areas is poor and streams may flow underground.
Piping: the slow subsurface removal of silt and fine sand from a sedimentary
deposit by groundwater. May produce surface cavities, tunnels and sink holes
Drainage Basin: an area that contributes surface water to a stream, also known as
catchment and watershed
Levee: a linear mound or embankment bordering a stream. Include natural features
consisting of fine sediment deposited by overbank flood flows and artificial
embankments constructed by humans to protect adjacent land from flooding
Blizzard: a severe winter storm during which large amounts of falling or blowing
snow create low visibility for an extended period. In Canada winds must exceed
40km/hr with less than 1km visibility for 4 hours by definition
Sandstorm: a storm with high winds that transport sand particles to heights of up
to 2m above the ground. Most occur in arid areas.
Typhoon: a hurricane in the western Pacific Ocean. “Scary wind, or wind from 4
directions: – Chinese)
Barrier Island: a long, narrow and low body of sand that is separated from the
mainland by a bay or lagoon.
Eutasy: a worldwide change in sea level especially one caused by changes in the
amount of glacier ice on land.
Swash Zone: an area along the shoreline where waves run up and recede.
Low level Waste: Radiation: the transfer of energy by electromagnetic waves or by moving
subatomic waves. Main mechanism by which heat is transferred from the sun to
earth, from earth’s surface to its atmosphere, and, to a lesser extent, from a wildfire
to the atmosphere.
Combustion: the phase of a wildfire following ignition; includes flaming, in which
fine fuel and volatile gases are rapidly oxidized in high temperatures, and glowing or
smoldering, which take place later at lower temps.
Pyrolysis: a group of chemical processes operating at high temps that split large
fuel molecules into smaller ones; the products of these processes are volatile gases,
mineral ash, tars and carbonaceous char.
Aerosol: a suspension of microscopic liquid and solid particles (mineral dust and
soot in the atmosphere)
Airburst: the explosion of a meteoroid in the atmosphere, generally at an altitude of
K-T Boundary: the boundary between the Cretaceous and tertiary periods, dating
to approx. 65 million years ago