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Global Change Quiz 1

Terms in this set (45)

Limnology
the study of inland waters
Lentic system
non-flowing water ecosystems; include ponds, lakes, and inland wetlands
Lotic/fluvial system
flowing water
Heat capacity
amount of energy needed to change the temperature
Heat of fusion/vaporization
amount of energy needed to melt/boil 1g of solid substance to liquid
Surface tension
tight water surface as a result of hydrogen bonding
Viscosity
the resistance of a fluid to change, "thickness"
Brownian motion
independent movement of water molecules at the microscope scale. Very fast.
Laminear flow
unidirectional movement of water at larger spacial spaces
Turbulent flow
"mixing", flow in different directions
Watershed
an area of land that drains from a common point
Impervious surfaces
a hard surface material, such as asphalt or concrete that emits infiltration and include high runoff rates
Ephemeral
temporary; usually present when precipitation is frequent or during snowmelt events
Perennial
permanent; flow levels fluctuate with variation in precipitation but the stream is always there. Most of these are fed by groundwater
Gaining stream
groundwater recharges the stream
Losing stream
the stream recharged the groundwater supply
Flow path determinants
climate (precipitation), soil composition (runoff, infiltration, percolation), topography (basin and channel)
4 dimensions of lotic systems
longitudinal, vertical, lateral, time
Stream order classification
measures stream size, standard for all fluvial systems, strong correlation to other characteristics
Fluvial hierarchy
1st order: headwater streams, draining independently without tributaries
2nd order: stream reaches below the junction of two first order streams
3rd order: stream reaches below the junction of two streams with same previous order
Tributary
a stream that drains directly into another stream
Length and stream order
positive relationship
Number and stream order
negative relationship
Total length and stream order
negative relationship
Discharge
the volume of water passing through a cross section area of the stream channel per unit of time
(directly proportional to precipitation and watershed's profile)
Peak
point of maximum discharge
Lag-time
the time it takes the stream discharge to reach peak after a rain event
Hydrograph
continuous record of stream discharge plotted against time (volume/time)
Base flow
average stream flow during normal conditions, "minimum flow"
Natural flow regime
characteristic, regular flow variation of a river based on its geomorphology and regular climactic conditions
Environmental flow
minimum flow required by the stream community. The minimum flow requirement without any ecosystem properties or processes being affected.
Alterations to flow regime
impervious surfaces, increased transport of materials from the watershed
3 stages of rivers
youth: typically 1st-3rd order streams
mature: 3rd-5th order
old age: 5th and older
Scarp
active, eroding side of stream channel
Thalweg
deepest part of the channel
Erosion
most of the erosion occurs in the steep and high velocity parts of the stream network
Deposition
deposition and sedimentation increases as you move downstream
Meanders
large turns formed as a result of erosion and deposition, mainly form lower parts of the watershed
Sinuosity
channel distance/straight line down valley distance
Flood plan
flat area adjacent to the stream that gets flooded during extraordinary flow events
Pools
slower, calmer, and deeper areas with fine grained bottom deposits
Riffles
shallow regions paved by stones and gravel where the current moves more quickly and with more turbulence
Sediment Scale (Wentworth Scale)
Largest to smallest: Boulder, Cobble, Gravel, Sand, Silt
Sediment transport pathways
suspended load and bed load
Base level
Lowest point to which a stream can flow
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