Shaft constructed by preforming the structure at the surface
and then sinking it into the ground by excavating.
A rock or substance formed of calcium carbonate or magnesium
carbonate by biological deposition or inorganic precipitation,
or containing those minerals in sufficient quantities to effervesce
when treated with cold hydrochloric acid.
A large, more or less circular, basin-shaped volcanic depression
whose diameter is many times greater than the volcanic vent.
The optimisation of parameters such that the computer or physical
model best fits the observed field measurements
Principal module which is part of a shield machine as in microtunnelling
or of a TBM. Two or more may be used, depending on the installation
dimensions required and the presence of an articulated joint
to facilitate steering.
Generally, a measure of the openness of a stream to sunlight.
Specifically, the angle formed by an imaginary line from the
highest structure (for example, tree, shrub, or bluff) on one
bank to eye level at midchannel to the highest structure on
The zone above the water table in which water is held by surface
tension. Water in the capillary fringe is under a pressure less
Rocks (such as limestone or dolostone) that are composed primarily
of minerals (such as calcite and dolomite) containing the carbonate
ion (CO32-). Casing Pipe Method
Method in which a casing, generally steel, is pipe jacked into
place, within which a product pipe is later inserted.
A place where elements for immersed tunnels can be fabricated
in the dry, and which can be flooded to allow the elements to
be floated out and taken away. Generally used for concrete tunnels.
Catastrophic Rainfall Event
Rainfall event of return frequency far in excess of any sewerage
design performance criteria typically, say, a 1 in 200 year
storm Catchment Area
Area draining to a drain, sewer or watercourse
Sub-division of the system(s) under study by considering pipe
characteristics, environmental factors and strategic factors.
Electrical means of protecting ferrous (usually steel) mains
from corrosion. Caulking
General term which, in trenchless technology, refers to methods
by which joints may be closed within a pipeline or between lining
Closed circuit television used to carry out internal inspection
and survey of pipelines.
A method of assessing the condition or status of a water main
or public sewer, using cameras.
A below-grade portion of a building. See also basement. Center
An automated sprinkler system involving a rotating pipe or boom
that supplies water to a circular area of an agricultural field
through sprinkler heads or nozzles.
Impartial body, governmental or non-governmental, possessing
he necessary competence and responsibility to carry out certification
of conformity according to given rules of procedure and management
An underground covered watertight tank used for receiving and
storing sewage from premises.
See Cess Pit.
Part of a manhole or inspection chamber manufactured as a single
entity and intended to be joined with other chamber units
Component part of a manhole or inspection chamber manufactured
as a single entity and intended to be joined with other chamber
Component part of a manhole or inspection chamber manufactured
as a single entity and intended to be joined with other chamber
Erosion by flowing water and sediment on a stream channel;
results in removal of mud, silt, and sand on the outside curve
of a stream bend and the bed material of a stream channel.
The straightening and deepening of a stream channel to permit
the water to move faster or to drain a wet area for farming.
Renovation method in which a length of pipeline between two
access points is sealed by the introduction of one or more compounds
in solution into the pipe and surrounding ground and, where
appropriate, producing a chemical reaction. Such systems may
perform a variety of functions such as the sealing of cracks
and cavities, the provision of a new wall surface with improved
hydraulic characteristics or ground stabilisation.
An organochlorine insecticide no longer registered for use
in the U.S. Technical chlordane is a mixture in which the primary
components are cis- and trans-chlordane, cis- and trans-nonachlor,
A volatile organic compound containing chlorine. Some common
solvents are trichloroethylene, tetrachloroethylene, and carbon
A class of volatile compounds consisting of carbon, chlorine,
and fluorine. Commonly called freons, which have been in refrigeration
mechanisms, as blowing agents in the fabrication of flexible
and rigid foams, and, until banned from use several years ago
See Polycyclic aromatic hydrocarbon (PAH).
A marshy area where the ground is wet due to the presence of
seepage or springs.
Said of water with a pH between 5.5 and 7.4; pH modifier used
in the U.S. Fish and Wildlife Service wetland classification
A deep, steep-walled, half-bowllike recess or hollow situated
high on the side of a mountain and commonly at the head of a
glacial valley; and produced by the erosive activity of mountain
Civil defence / protection
Protection of the civilian population against the effects of
bombs, fallout, and chemical releases.
Class I Liner
Clasification developed by AWWA for a non-structural renovation
Class II Liner
Clasification developed by AWWA for a semi-structural lining
which has no inherent resistence to external buckling loads.
Class III Liner
Clasification developed by AWWA for a semi-structural liner
with sufficient buckling resistence to be free standing.
Class IV Liner
Clasification developed by AWWA for a fully structural liner.
Rock, such as sandstone, or sediment composed principally of
broken fragments that are derived from preexisting rocks which
have been transported from their place of origin.
General term for vitrified clay pipes.
Spherical device, having an indented surface, designed to be
carried through a drain or sewer by the flow to facilitate removal
The sum total of the meteorological elements that characterize
the average and extreme conditions of the atmosphere over a
long period of time at any one place or region of the Earth's
Shields which incorporate a closed pressure chamber and do
not allow direct access to the face.
Situation of the installed pipe, such that an interference
fit maybe created between the outside of the pipe and the inside
of the existing pipe. See Lining With Close-Fit Pipes.
Coastal Wastewater Outfall
The coastal site of discharge of liquid from a pipe. Applied
particularly to the point at which a sewer discharges to a treatment
works (possibly via a conduit) or receiving water course.
A system of sewerage whereby waste water and surface water
are carried in the same drains and sewers.
Combined Sewer Overflow
A device on a combined or partially separate sewerage system
designed to relieve the system of flows that are in excess of
a selected rate. The excess flows are then discharged, possibly
after solid material has been removed by a CSO, into a watercourse.
Water for use by motels, hotels, restaurants, office buildings,
commercial facilities, and civilian and military institutions.
The water may be obtained from a public supplier or it may be
Community In ecology, the species that interact in a common
A system by which grout is injected into the ground above a
tunnel and below man-made surface features. The intention is
to ameliorate the effects of surface settlement caused by the
The act or position of having met all legal and regulatory
Compressed Air Method
General term which, in trenchless technology, refers to the
use of compressed air within a tunnel or shaft in order to balance
ground water pressure and to prevent ingress into an excavation
open to the atmosphere.
The ratio of the quantity of any substance present in a sample
of a given volume or a given weight compared to the volume or
weight of the sample.
In general, the granting of a favor or a point during negotiations.
In business terms, can represent a contract allowing the building
and/or operation of a facility by another company.
Man-made or adapted water or waste water course or pipe.
Cone of depression The depression of heads around a pumping
well caused by withdrawal of water.
Cone Penetration Test
CPT is an in-situ method of testing soil using a Static or
Confined Aquifer (artesian aquifer)
An aquifer that is completely filled with water under pressure
and that is overlain by material that restricts the movement
Being limited in movement, view, travel, etc. May induce variable
psychological responses in persons using underground spaces.
A body of impermeable or distinctly less permeable (see permeability)
material stratigraphically adjacent to one or more aquifers
that restricts the movement of water into and out of the aquifers.
The flowing together of two or more streams; the place where
a tributary joins the main stream.
A coarse-grained sedimentary rock composed of fragments larger
than 2 millimetres in diameter.
Consequence Of Failure
Damage that can result from the discharge of large volumes
of water associated with a sudden or brittle failure.
The saving of energy by one project alternative in comparison
Constituent A chemical or biological substance in water, sediment,
or biota that can be measured by an analytical method.
The cost to create a facility. Depending on the specific context,
this term may include land purchase, design fees and all costs
necessary to put a facility into operation; or it may be limited
only to the costs of physical construction work.
The quantity of water that is not available for immediate reuse
because it has been evaporated, transpired, or incorporated
into products, plant tissue, or animal tissue. Also referred
to as "water consumption".
Recreational activities, such as swimming and kayaking, in which
contact with water is prolonged or intimate, and in which there
is a likelihood of ingesting water.
Substances present in the ground which are not part of the natural
soil; usually associated with ground usage.
Degradation of water quality compared to original or natural
conditions due to human activity.
See Lining With Continuous Pipe Continuous Survey
Any survey carried out along some or all of the length of a
pipeline, including soil resistivity and soil potential survey.
The area in a drainage basin that contributes water to streamflow
or recharge to an aquifer.
Section of a drain or sewer system where hydraulic conditions
are known and where any change in those conditions influences
the upstream and/or downstream water levels
Shields which allow some form of direct access to the soil face.
Also known as open shields.
Method in which access is gained by excavation from ground level
to the required level underground for the installation, maintenance
or inspection of a pipe, conduit or cable. The excavation is
then backfilled and the surface reinstated.
Method of tunnel construction ranging from manual excavation
to the use of self-propelled tunnel boring machines. Where a
lining is required, bolted segmental rings are frequently used.
Changes in the distance between fixed points on a (cross-section
of a ) tunnel lining as a result of loading on the lining.
A ridge of limestone, composed chiefly of coral, coral sands,
and solid limestone resulting from organic secretion of calcium
carbonate; occur along continents and islands where the temperature
is generally above 18 C.
A sample of rock, soil, or other material obtained by driving
a hollow tube into the undisturbed medium and withdrawing it
with its contained sample.
The extent to which pipeline deterioration appears to be a function
of a particular set of physical or environmental factors.
Localised areas of intense corrosion (often very relevant on
ferrous mains) sometimes linked to coating damage.
Having a benefit-cost ratio greater than "1" when
all costs and benefits can be monetarised. Otherwise, cost judged
to be worthwhile against benefits. When several options are
being compared, the option with the highest benefit-cost ratio.
Cost of a project
Totality of expenditures implied by the implementation of that
project. If expenditures are spread over time, they must normally
be discounted, which is indicated by using the term "discounted
Cost-Benefit Analysis (study)
Cost-benefit analysis consists of identifying and quantifying
the costs and benefits and, where possible, ascribing values
to them. It is used particularly for non-marketable goods.
Amount of rock and/or soil over the arch of a tunn
Crack lines visible along the length and/or circumference.
Factors by reference to which a decision is taken. Multi-criteria
analysis may also be carried out, possibly incorporating cost-benefit
analysis as one of the criteria.
A standard rule or test on which a judgment or decision can
Sewers with the most significant consequences in the event of
A section of utility line where a pipe or cable has to pass
under an existing road, railway, river or other area where the
surface should not be disturbed.
The upper section in the stepped excavation of a tunnel excavated
in two or more horizontally stepped stages. It is the first
section to be excavated.
Rocks (igneous or metamorphic) consisting wholly of crystals
or fragments of crystals. CSD
See Crude Sewage Discharge.
Cubic Foot Per Second (ft3/s or CFS)
Rate of water discharge representing a volume of 1 cubic foot
passing a given point during 1 second, equivalent to approximately
7.48 gallons per second or 448.8 gallons per minute or 0.02832
cubic meter per second. In a stream channel, a discharge of
Cut and Cover (construction, method)
Underground construction involving open-cut excavation followed
by eventual covering with a slab or arch structure to support
a replaced ground surface. A temporary covering at ground level
may be provided for the passage of traffic or environmental
The front end of a mechanical excavator, usually a wheel, which
actually cuts through rock or soft ground.
Tool or system of tools on a common support which excavates
at the face of a bore. Usually applies to mechanical methods
of excavation. CWO
See Coastal Water Outfall.
An area of low pressure around which winds rotate counterclockwise
in the Northern Hemisphere and clockwise in the Southern Hemisphere.
See also Tropical cyclone
Small, isolated, circular, depressional, forested wetlands,
in which cypress predominates, that have convex silhouettes
when viewed from a distance.