Terms of Hydrology (C)

cableway :

Cable stretched above and across a stream, from which a current m ...

calibration :

Experimental determination of the relationship between the quanti ...

calibration tank :

Tank containing still water through which a current meter is move ...

calving :

Breaking away of a mass of ice from an ice wall, ice front or ice ...

canal :

Man-made open channel, usually of regular cross- sectional shape.

canyon :

Deep valley with high, steep slopes, often with a river flowing a ...

capacity :

(1) Maximum volume that can be contained by a reservoir. (2) Maxi ...

capillarity :

Phenomenon which is associated with the surface tension of liquid ...

capillary action :

Action due to capillarity, e.g. holding water in the soil against ...

capillary conductivity :

Coefficient which measures the extent to which a permeable medium ...

capillary diffusion (of water) :

Movement of water by capillarity in a porous medium.

capillary fringe :

Zone immediately above the water table in which all of the inters ...

capillary hysteresis :

Phenomenon that the retention curves in soil drainage and wetting ...

capillary interstice :

Interstice small enough to hold water against gravity above a wat ...

capillary potential :

Work required to move a unit weight of water from a free-water su ...

capillary pressure :

Difference of pressure across a curved air/water interface.

capillary rise :

(1) Rise of a liquid in a capillary tube, immersed in a liquid, m ...

capillary suction :

Phenomenon due to capillary forces that causes a liquid below atm ...

capillary water :

Water held in the soil above the water table by capillarity; soil ...

capillary-tube model :

Model simulating flow through soils by flow through a bundle of p ...

capture :

Diversion of the flow of water generally in the upper part of a s ...

carbonate hardness :

Hardness of water resulting from the presence of dissolved calciu ...

carryover storage :

Storage of water collected during a wet surplus year used for mak ...

cascade :

Small waterfall or one of a series of small falls.

catabolism :

Breaking down of living matter.

cataract :

Great waterfall.

celerity :

Speed of propagation of a wave.

channel :

(1) Deepest portion of a river bed, in which the main current flo ...

channel detention :

Volume of water which can be temporarily stored in channels durin ...

channel flow :

Flow of water with a free surface in a natural or artificial chan ...

channel precipitation :

Precipitation falling directly on the water surface within a chan ...

channel scour :

Erosion of a channel.

channel storage :

Volume of water stored in a channel.

chemical oxygen demand (COD) :

Mass concentration of oxygen equivalent to the amount of a specif ...

climate :

Synthesis of weather conditions in a given area, characterized by ...

climatic change :

Significant change observed in the climate of a region between tw ...

climatic region :

Region in which there is a relatively uniform climate, according ...

climatic year :

Continuous twelve-month period during which a complete annual cli ...

climatological station :

Station from which climatological data are obtained. (TR)

climatological station for hydrological purposes :

Climatological station set up in a drainage basin specifically to ...

clogging :

Deposition of fine particles such as clay or silt at the surface ...

closed lake :

Lake, often in an arid region, losing water only by evaporation a ...

cloud seeding :

Introduction of particles of appropriate material (e.g. carbon di ...

cloud top temperature :

Temperature of cloud top or air nearly at that level as determine ...

cloudburst :

Rainstorm of extraordinary intensity and relatively short duratio ...

Coagulation :

Process of adding a chemical (the coagulant) which causes the des ...

coastal river :

Short river discharging directly into the sea.

coefficient of compressibility (of water) :

Relative decrease in water volume per unit increment of pressure ...

coefficient of consolidation :

Relative decrease in soil volume by consolidation per unit increm ...

coefficient of determination :

Square of the correlation coefficient between a dependent variate ...

coefficient of groundwater discharge :

Ratio of groundwater runoff, or total groundwater discharge of an ...

coefficient of hydraulic conductivity :

Numerical value expressing the hydraulic conductivity.

coefficient of intrinsic permeability :

Numerical value expressing the intrinsic permeability.

coefficient of roughness :

Numerical value expressing the influence of roughness of a channe ...

coefficient of variation :

Statistical parameter describing the change of a stochastic varia ...

coliform count :

Number of bacteria from the coliform group per ml of water. It is ...

collector well :

Well provided with horizontal tubular drains arranged in several ...

colloidal suspension :

Suspension containing particles often electrically charged which ...

colour composite; color composite (A) :

Colour picture produced by assigning a colour for a particular sp ...

compensating reservoir :

Secondary reservoir reducing discharge fluctuations due to peak-l ...

complete control :

Control where the elevation of the water surface upstream of the ...

complete freeze-up :

Freezing of the water in a river reach from the bed to the surfac ...

composite unit hydrograph :

Superposition of unit hydrographs for the important subdivisions ...

composite water sample :

Two or more samples or subsamples, mixed together in appropriate ...

compound cross-section :

Cross-section of a channel in which the width suddenly increases ...

compound hydrograph :

Hydrograph due to a sequence of storms when the flow caused by on ...

compound weir :

Weir containing two or more sections, which may be of different t ...

conceptual hydrological model :

Simplified mathematical representation of some or all of the proc ...

condensation :

Transition from the vapour to the liquid state.

conditional probability :

If E and F are events occurring according to a probability distri ...

cone of depression :

Depression, in the shape of a cone with convex upward limits, of ...

confidence band :

Area between the upper and lower confidence limits. (DST)

confidence interval :

Interval which includes the true value with a prescribed probabil ...

confidence level :

Probability that the confidence interval includes the true value. ...

confidence limits :

Values which form the lower and upper limits to the confidence in ...

Confined aquifer :

Aquifer overlain and underlain by an impervious or almost impervi ...

confining bed :

Formation overlying or underlying a much more permeable aquifer.

confluence :

Joining, or the place of junction, of two or more streams. (TR)

conjugate image :

Mirror image relative to plane groundwater equipotential.

conjunctive use :

Combined use of surface water and groundwater.

connate water :

Water entrapped in the interstices of a sedimentary rock at the t ...

conservative pollutants :

Non-biodegradable pollutants.

Consolidation :

Settling of a soil in response to increased or continuing load, l ...

constant-rate dilution gauging :

Determination of flow characteristics (velocity or discharge) by ...

consumptive use :

Quantity of surface and groundwater absorbed by crops and transpi ...

contact angle :

Angle between the interface separating two immiscible fluids and ...

contact spring :

Spring issuing from a permeable formation overlying a relatively ...

contamination :

Introduction into water of any undesirable substance not normally ...

continental hydrology :

That branch of hydrology which refers to hydrological processes i ...

continuity equation :

Equation describing the conservation of mass of flowing matter (e ...

continuous stream :

Stream whose flow is not interrupted in space.

contour (-line) :

Line on a map indicating the locus of points at which a certain p ...

contracted weir :

Weir having a crest that does not extend across the whole channel ...

contraction coefficient :

(1) Ratio between the decreased length, area of section, or volum ...

Control :

Physical properties of a channel which determine the relationship ...

control section :

(1) Reach of a stream channel in which there exists a unique disc ...

control well :

Pumped well, or recharge well, used for an aquifer test, distingu ...

convective precipitation :

Precipitation caused by convective motion in the atmosphere.

conveyance :

Physical characteristic of an open channel flowing bankfull takin ...

correction :

Change to be made to the result of a measurement to allow for any ...