Groundwater Flashcards
Hydrology
the study of the movement and characteristics of water on and within land
water we can see vs what is harder to see
we can see water moving from place to place in the rivers on earths surface and we can see water stored on the surface in lakes and oceans
harder to see the massive amounts of water stored in the atmosphere and underground and the flows into and out of these storage places
groundwater
becomes groundwater when rain sinks into the ground
mass of water stored beneath earth’s surface
reservoir
a place where water is stored
percentage of earth that is salt water
95.9%
percentage of earth that is freshwater
** total 4.04% glaciers and polar ice 2.97% atmosphere .001% lakes and rivers .009% ** underground waters 1.05% biosphere .0001%
infiltration
process by which water enters rock or soil through joints in small pore spaces between particles
runoff
sum of all rainwater that flows over surface
eventually goes to ocean
if land is more developed, there is more runoff bc less earth to sink into
strongest influence on hydrology
geology of land and climate (including temp and precip)
droughts
periods of months to years, when precip is much lower than normal
hydrology of runoff
flash floods after torrential rains
surface runoff collected and stored in natural lakes and artificial reservoirs created by the damming of rivers
**wetland areas, swamps, and marshlands also act as storage deposits for runoff
how water flows through soil and rock
we know that water moves into and through the ground
there are no large open spaces for pools or rivers of water underground
the only space available for water is the pore space between grains of sand and otehr particles that make up the soil and bedrocks
some pores, however small and few, are found in every kind of rock and soil but large amounts of pore space most often found in sandstones
porosity
the amount of pore space in sock, soil, or sediment
the ratio, usually expressed as a %, of total volume of voids of a given porous medium to the total volume of the porous medium
depends on size, shape of grains and how they are packed together
(pics on page 2 and 3)
permeability
the ability of a solid to allow fluids to pass through it
spaces connected- fluids pass throughout
(pics on page 2)
different types of rock and their porosity
20% vesicular <1% basalt 25% limestone (with solution cavities) 5% shale **30% well-sorted eolian sandstone (grains round and same size) 15% poorly sorted sandstone **30% conglomerate unconformity < 1% granite (top of p 3)
different types of sandstone
** porous sandstone (the best kind)- bc rocks big and have large spaces between them
cemented sandstone- large rocks but cement in between
fine-grained sandstone
sandstone w irregular shapes- small grains fill space in between large grains
*unfractured shale (have many pores, which is good but not connected)
* fractured shale (better bc pores connected)
porosity and permeability of aquifer rock types
LOOK AT CHART ON PAGE 4 OF PACKET
aquifer
sediment or rocks that stores and transmits groundwater in sufficient quantity to supply wells
aquitard
sediment or rock that hinders water flow. A confining bed that retards but does not prevent the flow of water to or from an adjacent aquifer; a leaky confining bed
aquicludes
relatively impermeable beds. A hydrogeologic unit, which although porous and capable of storing water, does not transmit it at rates sufficient to furnish appreciable supply for a well or spring
confining unit
a hydrogeologic unit of impermeable or distinctly less permeable material bounding one or more aquifers and is a general term that replaces aquitard, aquiclude
unconfined aquifer
intersects the surface
in contact with atmosphere, easily contaminated
water travels through beds that extend with more or less uniform permeability to the surface in both discharge and recharge areas
level of reservoir in unconfined aquifer is
same height as the water table
