Chapter 9: Running Water and Groundwater

The amount of worldwide annual precipitation is _________________ the amount of worldwide annual evaporation.

the same as

Defined geologic features or descriptive terms that serve to "hold" water as it moves through the hydrologic cycle are called _________

reservoirs

Correctly match the following reservoirs with the correct percentage of the hydrosphere

97.2% Oceans

2.15% Ice/glaciers

0.62% Groundwater

0.03% All other (lakes, rivers, atmosphere, etc.)

The volume of water flowing past a certain point (measured in cubic feet per second) is known as ____________.

discharge

Which one of the following would least likely be found in a wide valley?

Rapids

Raising a stream's base level will cause the stream to _________.

deposit

As velocity drops abruptly when a stream or river enters quieter waters of an ocean or lake a depositional feature called a _____ is formed

delta

What are permeable rock strata or sediment that can store and transmit groundwater freely called?

Aquifers

The percentage of the total volume of rock or sediment that consists of voids or spaces is the ____________.

porosity

Severe examples of land subsidence, such as what happened in the San Joaquin Valley, occur as ___________.

groundwater is pumped heavily

The greatest single use of pumped groundwater from wells in the United States is for __________

irrigation (agriculture)

Which of the following is not part of the water cycle?

calcium carbonate dissolving in soil water and groundwater

Sinkholes and karst topography are a clear indication that ________.

the groundwater is moving through a limestone and forming caves that periodically collapse

Porosity is a measure of the volume of open space in rocks and unconsolidated geological materials such as alluvium and soils.

True

One environmental problem associated with groundwater is land subsidence caused by withdrawal.

True

Approximately how much of the Earth's water supply is saline?

98%

Sediment is neither stored nor produced ________. It is primarily a zone of transport in a river system.

in the trunk stream

A stream's turbulence is strongly influenced by its ________.

velocity

________ describes the total sediment load transported by a stream

Capacity

The single most important erosional agent is ________.

running water

The lowest base level for most streams is sea level

True

Permeable rock strata or sediment that transmit groundwater freely are called ________

aquifers

WATER IS CONTINUALLY ON THE MOVE, from the ocean to the land and back again, in an endless cycle

true

Water is constantly moving among Earth's different spheres—the hydrosphere, the atmosphere, the geosphere, and the biosphere. This unending circulation of water is called

Hydrologic Cycle

The unending circulation of Earth's water supply. The cycle is powered by energy from the Sun and is characterized by continuous exchanges of water among the oceans, the atmosphere, and the continents.

hydrologic cycle

When the rate of rainfall exceeds ground's ability to absorb it, the surplus water flows over the surface into lakes and streams, a process called

Runoff

some of the water that soaks into the ground is absorbed by plants, which then release it into the atmosphere this process is called

transpiration

Because both evaporation and transpiration involve the transfer of water from the surface directly to the atmosphere, they are often considered together as the combined process of

Evapotranspiration

If present-day glaciers were to melt and release all their water, sea level would rise by several dozen meters. Such a rise would submerge many heavily populated coastal areas

true

hydrologic cycle is balanced. The average annual precipitation worldwide must be equal to the quantity of water evaporated

true

continents taken together precipitation exceeds evaporation

true

over the oceans, evaporation exceeds precipitation

true

The land area that contributes water to a stream. Also called a watershed.

Drainage Basins

The extension upslope of the head of a valley due to erosion.

Headward erosion

The most commonly encountered drainage pattern is the (A stream system that resembles the pattern of a branching tree)

Dendritic pattern

When streams diverge from a central area like spokes from the hub of a wheel, the pattern is said to be (This pattern typically develops on isolated volcanic cones and domal uplifts)

Radial pattern

(exhibits many right-angle bends) This pattern develops when the bedrock is crisscrossed by a series of joints and/or faults.

Rectangular pattern

is a rectangular drainage pattern in which tributary streams are nearly parallel to one another and have the appearance of a garden trellis

Trellis pattern

In very slowly flowing streams, water moves in nearly straight-line paths parallel to the stream channel; this is called

Laminar flow

Movement of water in an erratic fashion, often characterized by swirling, whirlpool-like eddies. Most streamflow is of this type

Turbulent flow

The slope of a stream channel expressed as the vertical drop of a stream over a specified distance is the

Gradient

the volume of water flowing past a certain point in a given unit of time

Discharge

Streams that exhibit flow only during wet periods are referred to as

Intermittent streams

In arid climates, many streams carry water only occasionally, after a heavy rainstorm, and are called

Ephemeral streams

pebbles caught in swirling eddies can act like "drills" and create potholes

true

a process in which rock is gradually dissolved by the flowing water

Corrosion

Sediment moving by (saltare = to leap) appears to jump or skip along the stream bed

Saltation

is the maximum load of solid particles a stream can transport per unit of time

Capacity

is a measure of a stream's ability to transport particles based on size rather than quantity

Competence

Unconsolidated sediment deposited by a stream

Alluvium

A _____ _______ is one in which the stream is actively cutting into solid rock

bedrock channel

When the bed and banks are composed mainly of unconsolidated sediment, the channel is called an

Alluvial channel

A curved lake produced when a stream cuts off a meander

Oxbow lake

The level below which a stream cannot erode. There is a lower limit to how deep a stream can erode, a limit called

Base level

Sea level is considered the ultimate base level because it is the lowest level to which stream erosion could lower the land

true

A meandering channel that flows in a steep, narrow valley

incised (incisum = to cut into) meanders

An accumulation of sediment formed where a stream enters a lake or an ocean

Delta

A tributary that flows parallel to the main stream because a natural levee is present

Yazoo tributary

Flash floods often occur with little warning and are potentially deadly because they produce rapid rises in water levels and can have devastating flow velocities

true

Water in the zone of saturation

Groundwater

Groundwater represents the largest reservoir of freshwater that is readily available to humans

true

Groundwater is thus a form of storage that sustains streams during periods when rain does not fall

true

Although a considerable amount of water can be present in the unsaturated zone, this water cannot be pumped by wells because it clings too tightly to rock and soil particles

true

A measure of a material's ability to transmit water

Permeability

clay is impermeable.

true

Impermeable beds that hinder or prevent groundwater movement

Aquitard (aqua = water, tard = slow).

Many springs form when an aquitard blocks the downward movement of groundwater and forces it to move laterally

true

A fountain of hot water that is periodically ejected

Geyser

Given enough time, a downward-growing stalactite and an upward-growing stalagmite may join to form a column

true

Karst areas typically have irregular terrain punctuated with many depressions called sinkholes

true