Water Resources Flashcards
What is the distribution of water on Earth?
ocean water (97.2%) and freshwater (2.8%) > glaciers, groundwater, accessible freshwater > lakes, swamps, rivers
What is transpiration?
water released by vegetation
What happens to the water that falls as precipitation (5)?
- immediately evaporates
- transpired by plants
- surface runoff
- collects as groundwater
- soil-moisture zone
What is the soil water budget?
the balance between how much water is entering into a system compared to how much is needed to maintain current conditions
What is the water balance equation?
- when ACTET is greater than POTET, a significant surplus of water is present
- when ACTET equals POTET, conditions are good
- when ACTET is less than POTET, a deficit of water occurs
What factors influence precipitation amounts (2)?
- latitude
- elevation
What factors influence POTET (2)?
- latitude
- elevation
What is a water deficit?
a situation where POTET exceeds ACTET (drought)
What is the difference between a perennial and an intermittent stream?
- prennial: a stream or a river which continuously flows (year-round)
- intermittent: a stream or a river which does not continuously flow (not year-round)
What is groundwater?
any water that is located below the surface
What is groundwater recharge?
the slow process by which groundwater resources are replenished through precipitation and aquifers
What is subsidense?
the sinking of land over a drained aquifer
What is one of the most important aquifers in the U.S.?
the High Plains/Ogalala Aquifer
What is the zone of aeration?
layer of rock with some water but not completely saturated
What is the zone of saturation?
layer of rock with lots of water; completely saturated
What is impermeable rock?
rock which water cannot flow through
What is permeable rock?
rock which water can flow through
What is a water table?
the boundary between the zone of aeration and the zone of saturation
What is an aquifer?
a saturated layer of rock
What is an unconfined aquifer?
an aquifer that has permeable rock only on one side
What is a confined aquifer?
an aquifer that is confined on both sides by impermeable rock
What is a well?
a hole that taps into groundwater
What is an Artesian well?
form in conjunction with confined aquifers; water is pushed to the surface by pressure on both sides of the aquifer
What is well draw-down?
depression that occurs in clos proximity to any well (by-product of overuse)
