Geology Final Chapter 11

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