Porosity
is the percentage of a rock or sediment that consists of void space
Artesian
In a(n) _____ aquifer water rises above the top of the aquifer when a drill penetrates it
Losing Streams
In very dry climates such as deserts, rivers tend to be
Impermeable
An _____ rock is one that does not allow water to flow through it easily
Vadose Zone
The _____ is the zone above the water table
Drawdown
Local lowering of the water table, called ____, tends to change the direction of groundwater flow by changing the slope of the water table
Water Table
The upper surface of the saturated zone is called the
Cone of depression
When water is pumped out of an unconfined aquifer through a well, a ___ often develops in the water table
Aquifer
A(n) _______ is a body of saturated rock or sediment through which water can move easily
30-50
A deposit of loose sand may have a porosity of _____ percent
Gaining
______ streams receive water from the saturated zone
Rise to level of water table
In unconfined aquifers water in shallow wells
Zone above water table
The unsaturated zone is
Caves
form when slightly acidic ground water dissolves limestone along joints and bedding planes
Darcy's Law
states that the velocity of ground water equals permeability multiplied by hydraulic gradien
Greater hydraulic gradient
Given all other conditions are the same, ground water flows faster if it is flowing in response to
Permeability
refers to the ability of a rock to transmit fluids
Parallels land surface
The water table roughly ______ in humid regions
Hydralic Head
Elevation plus pore fluid pressure at a given point is
Infiltrate to top of water table
Gasoline leaking from an underground storage tank will ___ on which it will float
Spring
A ________ is a place where water flows naturally from rocks onto the ground surface
Perched water table
A(n) ____ is a body of ground water separated from the main water table by a zone that is not saturated
Well
A _____ is a deep, cylindrical hole that is dug or drilled into the ground to penetrate an aquifer within the saturated zone
Drop to deeper depths
Heavy use of ground water can cause a region's water table to
Sandstone, Conglomerate
Most ________ and _________ are both porous and permeable
Many times
The amount of ground water is ____ that of all rivers and lakes combined
Sinkholes
are closed depressions found where land surfaces are underlain by limestone bedrock
Geyser
A _______ is a type of hot spring that erupts hot water and steam
Karst
An area with many sinkholes and caves is said to have ___ topography
Permeability
Shales can have substantial porosity but have low
Stalactites
_ are icicle-like pendants of calcite hanging from cave ceilings
Confined
A(n) _________ aquifer is completely filled with water under pressure and is separated from the surface by an aquitard
Aquitard
Shale is a common _____ because it retards the flow of ground water
Salt-water intrusion
__ into wells is becoming a serious problem as demand for drinking water increases in coastal cities