Topographical Maps: Concepts & Terms to Know
● Gradient: The slope (Steepness) of a stream channel along the along its length. ● Longitude: (Vertical) a geographic coordinate that specifies the east-west position of a point on the Earth's surface.
● Latitude: (horizontal) the angular distance of a place north or south of the earth's equator, or of a celestial object north or south of the celestial equator, usually expressed in degrees and minutes.
● scale and scale calculations:
○ Ratio Scale
○ Fractional Scale
● contour line: a line joining points of equal elevation on a map
● relief: difference between the highest and lowest elevations in an area. ● magnetic declination: the angle on the horizontal plane between magnetic north (the direction the north end of a compass needle points, corresponding to the direction of the Earth's magnetic field lines) and true north (the direction along a meridian towards the geographic North Pole).
● rules of contour lines:
1. Every point on a contour line is of the exact same elevation; that is, contour lines connect points of equal elevation
2. Contour lines always separate points of higher elevation (uphill) from points of lower elevation (downhill).
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4. The elevation between any two adjacent contour lines of different elevation on a topographic map is the contour interval. Often every fifth contour line is heavier so that you can count by five times the contour interval. These heavier contour lines are known as index contours, because they generally have elevations printed on them.
5. Contour lines never cross one another except for one rare case: where an overhanging cliff is present. In such a case, the hidden contours are dashed
6. Contour lines can merge to form a single contour line only where there is a vertical cliff. 7. Evenly spaced contour lines of different elevation represent a uniform slope 8. The closer the contour lines are to one another the steeper the slope. In other words, the steeper the slope the closer the contour lines are.
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9. A concentric series of closed contours represent a hill
10. Depression contours have hachure marks on the downhill side and represent a closed depression.
11. Contour lines form a V pattern when crossing streams. The apex of the V always points upstream(uphill).
12. Contour Lines that occur on a opposite side of a valley always occur in pairs.
● Alluvial fan: A wedge-shaped sediment deposit left where a tributary flows into a more slowly flowing stream: or where a mountain stream flows into a desert.
● Base level: the lowest elevation to which a stream can cut down; for most streams: this is the level
● Bed load: material moved along a stream bed by flowing water
● Braided stream: A stream with multiple channels that divide and rejoin ● Capacity: (Stream) the load that a stream can carry. Don't forget about the age old question of mechanics of materials study guide
● Channelization: the modification of a stream channel, such as a deepening or straightening of the channel, usually with the objective of reducing flood hazards ● Crest: the maximum stage reached during a flood event
● Cut bank: Steep stream bank being eroded by lateral migration of meanders ● Dams: a barrier constructed to hold back water and raise its level, the resulting reservoir being used in the generation of electricity or as a water supply.
● Delta: A fan-shaped deposit of sediment formed at a stream’s mouth. ● Discharge: (Stream) the amount of water flowing past a given point per unit time. ● Dissolved load: Sum of dissolved material transported by a stream. ● Diversion channels: Don't forget about the age old question of utsa population
● Downstream flood: A flood affecting a large area of drainage basin or a large stream system; typically caused by prolonged rai or rapid regional snowmelt. We also discuss several other topics like phy 1001
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● Drainage basin: the region from which surface water drains into a particular stream. ● flash flood: a sudden local flood, typically due to heavy rain.
● flood: Condition in which stream stage is above channel bank height. ● flood-frequency curve: A graph of stream stage or discharge as a function of recurrence interval (or annual probability of occurrence)
● flood stage: the level at which a body of water's surface has risen to a sufficient level to cause sufficient inundation of areas that are not normally covered by water, causing an inconvenience or a threat to life and/or property.
● Floodplain: a flat region or valley floor surrounding a stream channel, formed by meandering and sediment deposition, into which the stream overflows during flooding. ● Gradient: The slope (Steepness) of a stream channel along the along its length. ● hydrograph: a graph of stream stage or discharge against time
● hydrologic cycle: the cycle through which water in the hydrosphere moves; includes such processes as evaporation, precipitation, and surface and groundwater runoff. ● Hydrosphere: All water at and near the earth’s surface that is not chemically bound in rocks.
● Infiltration: the process by which surface water sinks into the ground. ● levee: raised banks along a stream channel that tend to contain the water during high-discharge events
● Load: (stream) the total quantity of material transported by a stream: sum of bed load, suspended load, and dissolved load
● longitudinal profile: diagram of elevation of a stream bed along its length.
● Meanders: the curves or bends in a stream channel
● Oxbows: old meanders now cut off or abandoned by a stream.
● Percolation: movement of subsurface water through rock or soil under its own pressure. ● point bars: a sedimentary feature built in a stream channel, on the inside of a meander, or anywhere the water slows.
● recurrence interval: the average length of time between floods of a given size along a particular stream.
● retention pond: a large basin designed to catch surface runoff to prevent its flow directly into a stream.
● Saltation: the process by which particles are moved in short jumps over the ground surface or stream bed by wind or water.
● stage: (stream) the height (elevation) of a stream surface at a given point along the stream’s length; usually expressed as elevation above sea level.
● stream: a body of flowing water confined within a channel
● stream capacity: a measure of the total sediment (material other than water) a stream can carry.
● stream gradient: the grade measured by the ratio of drop in elevation of a stream per unit horizontal distance, usually expressed as feet per mile or metres per kilometre. ● suspended load: (stream) the material that is light or fine enough to be moved along suspended in the stream, supported by the flowing water
● traction: large boulders and rocks are rolled along the river bed.
● upstream flood: flood affecting only localized sections of a stream system; caused by such events as an intense, local cloudburst or a dam failure; typically brief in duration ● V-shaped valleys:
● watershed: synonym for drainage basin
● well/poorly sorted:
○ Well-Sorted: describes sediments displaying uniform particle size and/or density ● 100-year flood: a flood event that has a 1% probability of occurring in any given year. COASTAL PROCESSES
● Abrasion: erosion by wind-transported sediment or by the scraping of rock fragments frozen in glacial ice.
● active margin: a continental margin in which there is a significant volcanic and earthquake activity; commonly, a convergent plate margin.
● barrier islands: long, low, narrow islands parallel to a coastline that protect the coastline somewhat from wave action.
● beach: gently sloping shoreline area washed over by waves.
● beach face: that part of the beach along the water that is regularly washed by waves ● berm: a flat strip of land, raised bank, or terrace bordering a river or canal ● breakwater: a barrier built out into a body of water to protect a coast or harbor from the force of waves.
● cliff erosion: the wearing away of land and the removal of beach or sand dunes sediments by wave action, tidal currents, wave currents, drainage or high winds ● coasts: the part of the land near the sea; the edge of the land.
● currents: a body of water or air moving in a definite direction, especially through a surrounding body of water or air in which there is less movement
● drowned valley: along a coastline, a stream valley that is partially flooded by seawater as a consequence of land sinking and/or sea level rising
● dune: a low mound or ridge of sediment (usually sand) deposited by wind. ● estuary: a body of water along a coastline that contains a mix of fresh and salt water ● fjords: a long, narrow, deep inlet of the sea between high cliffs, as in Norway and Iceland, typically formed by submergence of a glaciated valley.
● groins: a rigid hydraulic structure built from an ocean shore (in coastal engineering) or from a bank (in rivers) that interrupts water flow and limits the movement of sediment. It is usually made out of wood, concrete or stone.
● hard structural stabilization: may also be built parallel to the shoreline to protect property and coastal structures.
● hurricanes: A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain.
● littoral drift: sand movement along the length of a beach.
● longshore current: net movement of water parallel to a coastline, arising when waves and currents approach the shore at an oblique angle.
● milling: Erosion by the grinding action of sand-laden waves on a coast. ● neap tides: a tide just after the first or third quarters of the moon when there is the least difference between high and low water.
● passive margin: a geologically quiet continental margin, lacking significant volcanic or seismic activity.
● sand transport:
● sea-level change:
● Hard and soft structure stabilization:
○ may also be built parallel to the shoreline to protect property and coastal structures. A breakwater is a hard stabilization structure built offshore and parallel to the beach to protect the coast and create a calm area of water.
● spring tides: a tide just after a new or full moon, when there is the greatest difference between high and low water
● storm surge: a rising of the sea as a result of atmospheric pressure changes and wind associated with a storm.
● thermohaline circulation (also covered in chapter 10): (THC) is a part of the large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes.
○ wavecute platform:
○ wave erosion:
○ wave refraction
● Angle of repose: the maximum slope angle at which a given unconsolidated material is stable.
● creep (rock or soil): slow, gradual downslope movement of unstable surficial materials (as contrasted with more abrupt landslides)
● debris avalanche: a mixed flow of rock, soil, vegetation, or other materials. ● debris flow: another term for debris avalanche; especially, used for a water-saturated one
● fall: (rock) mass wasting by free-fall of material not always in contact with the ground underneath.
● flow: mass wasting in which materials move in chaotic fashion.
● frost heaving: an upwards swelling of soil during freezing conditions caused by an increasing presence of ice as it grows towards the surface, upwards from the depth in the soil where freezing temperatures have penetrated into the soil (the freezing front or freezing boundary).
● landslide: a general term applied to a rapid mass-wasting event
● landslide warnings:
● mass wasting/mass movements:
○ The downslope movement of material due to gravity
● quick clay: the sediment formed from glacial rock flour deposited in a marine setting, weakened by subsequent flushing with fresh pore water
● reducing landslide hazards:
● rockfall: mass wasting by free-fall of material not always in contact with the ground underneath
● rock flour: a fine sediment of pulverized rock produced by glacial erosion ● sensitive clay: a material similar in behavior to quick clay, but derived from different materials, such as volcanic ash.
● scarp: a very steep slope or bank.
● shearing stress: stress that tends to cause different parts of an object to slide past each other across a plane; with respect to mass movements, stress tending to pull material downslope.
● shear strength: the ability of a material to resist shearing stress
● slide: a form of mass wasting in which a relatively coherent mass of material moves downslope along a well-defined surface.
● slope stability: the potential of soil covered slopes to withstand and undergo movement ● slump: a slide moved only a short distance, often with a rotational component to the movement
● Talus: accumulated debris from rockfalls and rockslides
● Ablation: the loss of glacier ice by melting or evaporation
● abrasion: erosion by wind-transported sediment or by the scraping of rock fragments frozen in glacial ice.
● atmospheric circulation: the large-scale movement of air, and together with ocean circulation is the means by which thermal energy is redistributed on the surface of the Earth
● cross-beds: or "sets" are the groups of inclined layers, which are known as cross strata. ● deflation: the wholesale removal of loose sediment by wind erosion
● Desert: a barren region incapable of supporting appreciable life
● desertification: the process by which marginally habitable arid lands are converted to desert; typically accelerated by human activities
● drift: sediment transported and deposited by a glacier
● dune: a low mound or ridge of sediment (usually sand) deposited by wind ● dune migration:
● eolian: deposited or shaped by wind action.
● Hadley cell: a large-scale atmospheric convection cell in which air rises at the equator and sinks at medium latitudes, typically about 30° north or south.
● loess: wind-deposited sediment composed of fine particles (typically 0.01 to 0.06 millimeters in diameter)
● rain shadow: a dry zone landward of a mountain range, which is caused by loss of moisture from air passing over the mountains.
● slip face: the downwind side of a dune, on which material tends to assume the slope of the angle of repose of the sediment of the dune.
● ventifact: “wind-made” rock, shaped by wind erosion
● wind erosion: "eolian Erosion"
○ Wind carries sand/sediment particles, which abrade and erode
○ Can wear down rocks and shape them, showing wind direction
○ "Desert pavement": forms when wind carries away fine sediment, leaving behind pebbles
○ Sand dunes also demonstrate wind direction
Ice & Glaciers
● Ablation: the loss of glacier ice by melting or evaporation
● abrasion: erosion by wind-transported sediment or by the scraping of rock fragments frozen in glacial ice.
● alpine glacier: a glacier occupying a valley in mountainous train
● arête: sharp-spined ridge created by erosion by valley glaciers flowing along either side of the ridge
● calving: split and shed (a smaller mass of ice)
● continental glacier:
● equilibrium line: The line on a glacier that divides the zone of ablation from the accumulation zone
● firn: granular snow, especially on the upper part of a glacier, where it has not yet been compressed into ice.
● glacier: a mass of ice that moves or flows over land under its own weight ● glacial advance/retreat:
● glacier formation:
● horn: a peak formed by headwall erosion by several alpine glaciers diverging from the same topographic high.
● ice cap:
● ice sheet:
● loess: wind-deposited sediment composed of the particles (typically 0.01 to 0.0 millimeters in diameter)
● moraine: landform made of till
● outwash: Glacial sediment moved and redeposited by meltwater
● plucking: also referred to as quarrying, is a glacial phenomenon that is responsible for the erosion and transportation of individual pieces of bedrock
● striations: parallel grooves in a rock surface cut when a glacier containing rock debris flows over that rock
● surge: (storm) localized increase in water level of an ocean or large lake; caused by extreme low pressure and high winds associated with major storms
● till: poorly sorted sediment deposited by melting glacial ice
● U-shaped valleys:
● Earth’s climate system:
● thermal reservoir: a short-form of thermal energy reservoir, or thermal bath is a thermodynamic system with a heat capacity that is large enough that when it is in thermal contact with another system of interest or its environment, its temperature remains effectively constant.
● thermohaline circulation: major ocean circulation pattern, driven by winds and by differences in temperature and salinity of water masses
● El Niño: upwelling of cold water is suppressed for period of weeks or more and warm water from western South Pacific extend eastward to South America
● La Niña: Unusually cold surface waters off western South America
● upwelling: an oceanographic phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water towards the ocean surface, replacing the warmer, usually nutrient-depleted surface water.
● major controls on global climate:
● greenhouse effect: The warming of the atmosphere due to trapping of infrared rays by atmospheric gases, especially as due to the increased concentration of carbon dioxide derived from the burning of fossil fuels
● global energy balance:
● visible light:
● infrared rays: electromagnetic radiation just to the long-wavelength side of the visible light spectrum; heat radiation.
● Milankovitch cycles: cyclic variations in the amount of sunlight reaching a given latitude, caused by variations in earth’s orbit and tilt on its axis.
● natural forcing mechanisms and radiative forcing factors:
● oxygen isotope ratio:
● albedo: the fraction of incoming radiation that is reflected back by a surface ● carbon dioxide:
● natural versus amplified warming:
● nitrous oxide: chemical compound, commonly known as laughing gas/nitrous ● ozone:
● halocarbons: a chlorofluorocarbon or other compound in which the hydrogen of a hydrocarbon is replaced by halogens.
● water vapor:
● sea ice: simply frozen ocean water.
● aerosols: a substance enclosed under pressure and able to be released as a fine spray, typically by means of a propellant gas.
● black carbon:
● deforestation: removal of a forest
● positive feedback cycles:
● negative feedback cycles.
Streams & Flooding
Q=A x V
A = cross-sectional area of the stream
where Δh is the CHANGE IN ELEVATION
Δd= CHANGE IN HORIZONTAL DISTANCE
R= Recurrence Interval
N= Number of years of data
M= rank in terms of stage/discharge
M=1: largest flood
M=N: smallest flood
Probability of a flood occurring in a given year
R= recurrence interval
Wind & Deserts
Relative Humidity= 100% x Amount of water in air
Total amount of water air can hold at that temperature