Terms of Hydrology (M)

macro-permeability :

Permeability of a rock or soil due mainly to the existence of large cracks ...

macrophytes :

Large water plants.

magmatic water :

Water brought to the Earth's surface from great depths by the upward moveme ...

Markov chain :

Markov process in which the time parameter is discontinuous.

Markov process :

Stochastic process such that the conditional probability distribution for t ...

marsh :

Lowland flooded in the rainy season, and usually watery at all times.

mass curve :

Curve of an accumulated quantity versus time.

mass-transfer method :

Method for estimating evaporation, assuming that it is proportional to wind ...

maximum possible flood :

Greatest flood to be expected, assuming complete coincidence of all factors ...

maximum probable flood :

Greatest flood that may be expected, taking into account all pertinent fact ...

mean deviation :

Measure of dispersion derived from the arithmetic mean of the deviations of ...

mean monthly discharge :

Arithmetic mean of all the individual monthly mean discharges for a named m ...

mean sea level :

Mean datum about which the sea tide oscillates in a long-term period.

meander :

One curved portion of a sinuous or winding stream channel, consisting of tw ...

meander belt :

That part of a valley floor situated between two parallel lines tangential ...

meander length :

Distance along the river between two corresponding points at the extreme li ...

meander width :

Amplitude of swing of a meander, measured from midstream to midstream.

mean-section method :

Method for computing the discharge of a stream by dividing the cross-sectio ...

measuring weir :

Device or structure across a stream which causes a free or submerged fall a ...

median :

For a continuous frequency distribution, the value of the variate which div ...

medium-term (extended) hydrological forecast :

Forecast of the future value of an element of the regime of a water body fo ...

meromictic lake :

Lake which undergoes incomplete circulation at the autumn overturn.

mesophyte :

Plant that grows under intermediate moisture conditions.

mesosaprobic :

Pertaining to an intermediate condition between polysaprobic and oligosapro ...

mesotrophic :

Pertaining to an intermediate condition, naturally occurring or due to nutr ...

mesotrophic lake :

Lake containing a moderate amount of plant nutrients.

metamorphic water :

Water that is driven out of rocks by the process of metamorphism.

meteorological (weather) radar :

Method, system or technique, including equipment components, for using beam ...

meteorology :

Science of the atmosphere.

method of images :

Method for solving problems of flow from sources and to sinks in bounded do ...

method of small squares :

Graphical method for obtaining flow nets.

microwave :

Very short electromagnetic wave between 1 m and 1 mm in wavelength or 300 G ...

mid-section method :

Method for computing the discharge of a stream by dividing the cross-sectio ...

mineral spring :

Spring the water of which contains significant quantities of mineral salts.

minimum annual flow :

Least value of discharge in a stream during a hydrological year.

miscible displacement :

Displacement of one fluid by another in flow through porous media, when the ...

mixing length :

(1) Length defined by Prandtl as being characteristic of turbulent flow. (2 ...

mixing ratio :

For moist air, ratio of the mass of water vapour to the mass of dry air wit ...

mixing zone :

Zone separating regions occupied by two physically or chemically different ...

mode :

In a distribution of a discrete variate, the variate which occurs most freq ...

model :

Representation in any form of an object, process or system. In hydrology, a ...

model calibration :

Adjustment of the parameters of a model, either on the basis of physical co ...

modular flow :

Flow across a measuring device in which the water level upstream is not inf ...

moment :

if the latter is the mean, the moments are central moments. (DST)

monitor well :

Observation well used to watch for the advent of an anticipated condition, ...

monitoring :

Continuous or frequent standardized measurement and observation of the envi ...

monomolecular layer :

Layer, one molecule thick, e.g. layer of fatty acid or some heavy alcohols ...

morphometrical characteristics of basin :

Characteristics of a drainage basin, e.g. basin area, longitudinal stream p ...

moving boat method :

Method of measuring discharge from a boat by traversing the stream along th ...

mudflow :

Flow of water so heavily charged with earth and debris that the flowing mas ...

multi-annual mean :

Arithmetic mean of the occurrences, over a number of years, of a hydrologic ...

multi-annual storage :

Volume of water that can be stored in a reservoir to cope, partly or comple ...

multiband system :

System for simultaneously observing the same (small) target with several fi ...

multi-channel system :

Scanning system capable of observing and recording several channels of data ...

multiple correlation :

Interdependence of more than two variables.

multiple correlation coefficient :

First product-moment correlation between the actual values of the "dependen ...

multiple regression :

Regression of a "dependent" variate on more than one "independent" variate. ...

multiple-objective planning :

Water resources planning in which a framework is provided for analysing the ...

multiple-phase flow :

Simultaneous flow of two or more phases.

multiple-purpose project :

Project designed, constructed and operated to serve more than one interest ...

multispectral (line) scanner :

Remote sensing device capable of recording data in both the ultraviolet, th ...

multispectral remote sensing :

Remote sensing in two or more spectral bands, such as visible and infrared. ...

muskeg :

In the northern United States and Canada: a swamp or bog in an undrained or ...

Muskingum method :

Approximate hydrological method of flood routing, based on the equation of ...