Minor FloodingA general term indicating minimal or no property damage but possibly some public inconvenience.
Mission of the Hydrologic Services ProgramTo provide river and flood forecasts and warnings for the protection of life and property and to provide basic hydrologic forecast information for the…
Mission of the National Weather ServiceTo provide weather and flood warnings, public forecasts and advisories for all of the United States, its territories, adjacent waters and ocean areas…
Mitigation (measures)Methods or actions that will reduce adverse impacts from solar facility development.
Mixed faceIn tunneling, digging in dirt and rock in the same heading at the same time.
ModelingThe use of statistical analysis, computer analysis, or model organisms to predict outcomes of research.
Moderate FloodingThe inundation of secondary roads; transfer to higher elevation necessary to save property -- some evacuation may be required.
Moderate frequency floodA flood of lesser magnitude than the IDF, used for the service spillway design when supplemented by a separate auxiliary spillway.
Modification Decision Analysis (MDA)The process of determining with confidence whether dam safety deficiencies exist for maximum loading conditions.
Modified homogeneous earthfill damA homogeneous earthfill dam that uses pervious material specially placed in the embankment to control seepage. See embankment dam.
Modified Mercalli scaleAn earthquake intensity scale which has twelve divisions ranging from I (not felt by people) to XII (nearly total damage).
Mohr circleA graphical representation of the stresses acting on the various planes at a given point.
Moisture content (water content)The ratio of the weight of water in a soil sample to the weight of the dry soil, expressed as a percentage. See optimum moisture content.
Moisture EquivalentThe ratio of (1) the weight of water which the soil, after saturation, will retain against a centrifugal force 1,000 times the force of gravity, to (2)…
MonoclineBend or steplike fold in rock layers where all strata are inclined in the same direction.
Monocoque gateA thin-shell radial gate in which the usual skin plate and cross-beam framework are replaced by a hollow shell having an approximate elliptical cross…
MonomicticLakes and reservoirs which are relatively deep, do not freeze over, and undergo a single stratification and mixing cycle during the year.
Morning glory spillwayA circular or glory hole form of a drop inlet spillway. Usually free standing in the reservoir and so called because of its resemblance to the morning…
Motor efficiencyThe ratio of energy delivered by a motor to the energy supplied to it during a fixed period or cycle.
Movable BedA stream bed made up of materials readily transportable by the stream flow.
Moveable Bed StreamsThese are most common in the arid West, where steep slopes and lack of vegetation result in a lot of erosion.
MS connectorsSurface delays for use when shooting with detonating cord.
MuckEight card decks used in Baccarat, 416 cards in total.
MudGenerally, any soil containing enough water to make it soft. A mixture of soil and water in a fluid or weakly solid state.
MudflatA mud-covered, gently sloping tract of land alternately covered and left bare by water. The muddy, nearly level bed of a dry lake.
MudstoneFine-grained sedimentary rock formed from hardened clay and silt that lacks the thin layers typical of shale.
MulchMaterial spread on the ground to reduce soil erosion and evaporation of water. Any substance spread or allowed to remain on the soil surface to conserve…
Multiple arch damA buttress dam, the upstream part of which comprises a series of arches.
Multiple useA combination of balanced and diverse resource uses that takes into account the long-term needs of future generations for renewable and nonrenewable…
Multiple-Use MPAsOften employed over larger areas, multiple-use areas allow for integrated management of complete marine ecosystems, usually through a zoning process.
Multipurpose damA dam constructed for two or more purposes (e.g. storage, flood control, navigation, power generation, recreation, or fish and wildlife enhancement.)
Multipurpose projectA project designed for irrigation, power, flood control, municipal and industrial, recreation, and fish and wildlife benefits, in any combinations of two…
Multipurpose ReservoirA reservoir constructed and equipped to provide storage and release of water for two or more purposes such as flood control, power development…
Municipal Use of WaterThe various uses of water in developed urban areas, including domestic use, industrial use, street sprinkling, fire protection, etc.