12: Freshwater of the Continents Flashcards
Water on the continents represents only __ of
the hydrosphere’s total water.
3%
derived from precipitation over the continents generated in the
operation of the global hydrologic cycle
fresh water
demonstrates how water is transformed and distributed
across the Earth.
evaporation, condensation,
and precipitation as well as evapotranspiration.
hydrologic cycle
plays an important role determining if precipitation will be directed
to the atmosphere by evapotranspiration, to groundwater by percolation, or to streams and rivers as overland flow
soil layer
refers to water beneath the surface that fully saturates the pore spaces in bedrock, regolith, or soil
Groundwater
marks the upper surface of the groundwater zone where the pore spaces in rock and regolith are completely filled
or saturated with water
water table
Groundwater return to the surface by __ into streams, rivers, ponds, and lakes
seepage
layer of rock or sediment that holds abundant free flowing ground
water
aquifer
movement of groundwater through highly soluble limestone rock produces distinctive __
karst landscapes
results of Human use of groundwater resources
depletion of groundwater resources, ground subsidence, and groundwater contamination
includes both overland flow and flow in stream and river channels
runoff
channels
collect overland flow from slopes and seepage from groundwater and transfer this
water downstream to larger channels.
drainage systems
includes all the land around the stream that supplies water to the stream
drainage basin
mark the ridges between
adjacent drainage basins
drainage divides
flow rate of water past a location on a channel, increases downstream through drainage networks as flow from tributary streams is collected
Discharge
plot showing the variation in the discharge of a stream over time
hydrograph
lag time between peak discharge and peak precipitation
reflects the time required for water to move down slopes and through progressively larger stream channels
occur when discharge exceeds the capacity of a river channel and water
flows over the low-lying floodplain adjacent to the channel.
Floods
important elements of the drainage system because they are sources of fresh water and are used for recreation and hydroelectric power generation
Lakes without a surface outlet often become saline as they lose water primarily through evaporation.
lakes
Saline lakes are characteristic of arid climates
desert areas relied on __
problems from salinization and water logging
exotic rivers
