Environmental Engineering Reference
In-Depth Information
Flood:
Any relatively high streamflow that overflows the natural or artificial
banks of a stream.
Flood attenuation:
A weakening or reduction in the force or intensity of a
flood.
Flood irrigation:
The application of irrigation water whereby the entire sur-
face of the soil is covered by ponded water.
Flood plain:
A strip of relatively flat land bordering a stream channel that is
inundated at times of high water.
Flow line:
The idealized path followed by particles of water.
Flowpath:
An underground route for groundwater movement, extending
from a recharge (intake) zone to a discharge (output) zone such as a
shallow stream.
Fluvial:
Pertaining to a river or stream.
Freshwater:
Water that contains less than 1000 mg/L dissolved solids.
Freshwater chronic criteria:
The highest concentration of a contaminant
that freshwater aquatic organisms can be exposed to for an extended
period of time (4 days) without adverse effects.
G
Grab sample:
A single water sample collected at one time from a single point.
Groundwater:
Freshwater found under the surface of the Earth, usually in
aquifers. Groundwater is a major source of drinking water and a
source of growing concern in areas where leaching agricultural or
industrial pollutants or substances from leaking underground stor-
age tanks are contaminating it.
H
Habitat:
The part of the physical environment in which a plant or animal
lives.
Hardness:
A characteristic of water caused primarily by the salts of calcium
and magnesium. It causes deposition of scale in boilers, damage in
some industrial processes, and sometimes an objectionable taste. It
can also decrease the effectiveness of soap.
Headwaters:
The source and upper part of a stream.
Hydraulic conductivity:
The capacity of a rock to transmit water. It is
expressed as the volume of water at the existing kinematic viscosity
that will move in unit time under a unit hydraulic gradient through
a unit area measured at right angles to the direction of flow.
Hydraulic gradient:
The change of hydraulic head per unit of distance in a
given direction.
Hydrogen bonding:
The term used to describe the weak but effective attrac-
tion that occurs between polar covalent molecules.
