Chapter 17 Flashcards
reservoir
each place that stores water
order of natural reservoirs (smallest to largest)
- oceans
- glaciers and polar ice
- groundwater
- lakes and rivers
- atmosphere
- biosphere
residence time
the amount of time a given amount of water spends in a reservoir
hydrologic cycle
the cyclical movement of water - through evaporation, precipitation, and runoff
What drives the hydrologic cycle?
the earth’s external heat engine; the sun
infiltration
the process by which water enter rock or soil through cracks or pores between particles
transpiritation
process by which moisture is absorbed by plant roots and carried through to the leaves then absorbed into the atmosphere
runoff
all water the flows above the land surface
what is the distribution (%) of water on the earth?
- Salt water ~ 96%
- Fresh water ~ 4%
- glaciers ~ 3%
- underground ~ 1 %
- atmosphere ~ .001%
- biosphere ~ .0009%
sublimation
the transformation of water from a solid directly to a gas
relative humidity
the amount of water vapor in the air relative to the maximum amount of water vapor the air can hold at that tempurature
rain shadow
areas with low precipitation on the leeward slope of mountains
meteoric water
groundwater formed from recent atmospheric percipitation
porosity
percentage of rock, soil, or sediment that is porous
permeability
the capacity of a solid to allow liquids to pass through it
What types of rock and sediments make good aquifers?
ones with high permeability and high porosity
unsaturated zone
soil and rock contains air as well as water
saturated zone
pores of soil and rock are completely filled with water
groundwater table
boundary between saturated and unsaturated zones
recharge
infiltration of water into the saturated zone
examples of recharge
rain and snow melting
discharge
movement of groundwater to the surface
examples of discharge
evaporation and pumping
aquiclude
relatively impermeable formations
confined aquifer
when aquicludes lie over and under the aquifer
how does water get into a confined aquifer
through a recharge area vertical and lateral to the confined aquifer
artesian fllow
water that moves through a confined aquifer
recharge area
are through which water enters a confined aquifer
what is the relationship between the rate at which water flows relative to the vertical drop in elevation of a water table?
directly proportional (the steeper the vertical drop, the faster the water flows)
what is the relationship between the rate at which water flows relative to the distance the water travels?
inversely proportional (the longer the distance, the lower the rate)
hydraulic gradient
ratio of the vertical drop to the flow distance
what is the main use of groundwater?
irrigation of crops
what are some dangers of using groundwater?
sink holes - create a space below ground that has a lower pressure due to absence of water and the ground could collapse
