Environmental Engineering Reference
In-Depth Information
Solution
The change of state of a solid or gas into a liquid by mixture with a
solvent
which forms an important chemical weathering process.
Solvent
A fluid capable of forming a
solution
with a solid or gaseous substance.
Species richness
The number of species of a defined taxonomic group in a specified
area.
Specific retention
The volume of water retained by an
aquifer
after gravity flow,
sometimes measured as a ratio of that volume to the volume of rock.
Specific susceptibility
The susceptibility of rock to a specific weathering process
determined by its specific lithological (chemical and structural) characteristics.
Specific yield
The volume of water released from an
aquifer
by gravity flow, sometimes
measured as a ratio of that volume to the volume of rock.
Spit
A narrow, coarse-grained sediment bar extended across a bay or estuary by
longshore drift
from a headland and often curved at its free end in response to
estuarine cross-currents.
Spring sapping
The undercutting or
headward retreat
of the slope immediately above a
spring or point of initiation of a stream channel by the concentration of erosive power.
Spring tide
The twice-monthly tidal period when the gravitational pull of the sun and
that of the moon are in line and maximize tidal range.
Stability of soil structure
The ability of the soil structural units to remain coherent under
an applied stress, e.g. raindrop impact, waterlogging or ploughing.
Stack
A residual rock pinnacle which marks coastal cliff retreat and/or the landward
advance of a
rock platform
.
Stage
The height of the water surface above a specific location in a fluvial channel,
usually the deepest point.
Standard deviation
A measure of the variability within a data set.
Standing crop
The total weight of living organic material per unit of area at any one
time.
Standing wave
A water wave which oscillates vertically between two points without
propagating horizontally.
Steady
-
state equilibrium
The state of a system where the steady output of matter and
energy is equal to the input over a particular period of time.
Stem flow
That portion of intercepted precipitation which is concentrated and transferred
towards the ground by plant stems and trunks.
Stomata
Microscopic pores on plant leaves through which most water vapour and other
gaseous exchanges take place.
Storage
Locations where energy and matter may be stored for certain periods of time.
Storage capacity
The amount of
available water
which a soil can hold.
Storm surge
An abnormal rise in sea level driven against the coast by extreme weather
events, most severe and liable to cause coastal damage when coinciding with high
spring tides
.
Stratified scree
Scree material showing apparent bedding planes dipping downslope,
suggesting episodic
solifluction
or
sheet flow
typical of a
permafrost
environment; this
may be so, or the structures may reflect post-depositional removal or settling of fines
or
platy
debris.