Earth Science CH. 11-13

The historic 1993 flood on the Mississippi River occurred because of ______.

both short- and long-term precipitation

As shown in this graph from the Toutle River in Washington, an increase in a river's sediment load is associated with an increase

discharge

The migration of a stream across a valley floor in the direction of erosion is called ____________ Migration

lateral

The lowest point a stream can flow is called base

level

Climate change is predicted to reservoir levels, energy production, and water supply in the southwestern United States.

lower

Which two of these units are commonly used to measure stream discharge?

m3s m3s ft3s

Changes to Earth's landscape, such as paved parking lots and housing developments, have an effect on streams because they ______.

may increase water runoff volume or increase runoff rate

Velocity across a stream channel varies. The lowest velocity is ______ of the stream, and the greatest velocity is ______ of the stream.

near the banks; in the center

___________lake is formed when a meander is cutoff from the river channel.

oxbow

Reservoirs in the southwestern United States may experience decreases in water levels due to ______.

predicted decreases in precipitation from global warming

There are two approaches to managing floods:________ seeks to stop floods from occurring, whereas_____ accepts the occurrence of floods and seeks to deal with them effectively.

prevention, adjustment

Data on floods is organized by the size of the flood and the time between floods of a similar size. The average time between floods of the same size is called the_______ interval.

r

Observe the image of the stream and where the path of maximum water velocity might be. At cross-section A, the maximum velocity would be near the ______ bank; cross-section B has maximum velocity near the middle of the channel; cross-section C has maximum velocity near the ______ bank.

right; left

The 1993 Mississippi River flood resulted in ______.

the submersion of 8 millions acres of farmland the halting of barge traffic for 2 months

The average residence time of a given volume of water in a stream is about ______ days.

14

What type of flood control system would be best for a community located at the end of an alpine valley, where irregular snowmelt or forest fires result in periodic flooding?

A dam

What type of flood control system would be best for a community located at the end of an alpine valley, where irregular snowmelt or forest fires result in periodic flooding? Multiple choice question.

A dam

How does abrasion cause erosion in streams?

Abrasion causes erosion to the streambed and banks due to impacts from small and large particles.

In this image, the area labeled A is a point_________ , and the area labeled B is a__________ bank.

Blank 1: bar Blank 2: cut

drainage patterns are V-shaped and form in areas with relatively uniform geology.

Dendritic

When levees or floodwalls may not be enough to protect a heavily developed area such as a large city from the threat of flooding, what engineered option may be employed?

Diversion channels

Viewing this image of a stream changing over time (beginning on the left, ending on the right), summarize what processes are causing the changes to the stream.

Erosion on one bank is paired with deposition on the opposite bank, moving the original path of the stream by lateral migration.

Braided streams, as shown in the image, are formed by deposits in the stream channel itself. What characteristic of the streams causes this braided formation?

Heavy loads

What two ways can flooding be caused by snow and ice melt? (Select two.)

Ice can break apart and jam stream channels, blocking the flow of water. Large amounts of snow can melt when temperatures rise quickly, releasing large quantities of water into streams.

Select the criteria that characterize a flood.

Land that is normally dry is covered with water. Water overflows a stream channel.

How do rivers respond to geologic processes?

Many rivers are the result of gradual geologic changes such as mountain formation or canyon erosion.

time is the length of time a certain volume of water will stay in a stream.

Residence

What creates the broad, flat features of floodplains?

Sediment deposits from floods that fill in and smooth the areas adjacent to stream channels

How is stream stage measured?

Stream stage is measured from an easily identified reference point to the surface of the water.

As mountain ranges rise during geologic uplift, highlands are drained, which leads to what process for streams and rivers?

Streams consolidate into larger river systems.

What characteristic of stream channels is described by stream channel roughness?

The makeup of the stream channel bottom and banks, such as rocky boulders or smooth mud

What is the ultimate base level, or the absolute lowest point a stream can flow?

The ocean

What role do dams and reservoirs have in providing flood control?

The store floodwaters and slowly release them after the threat of flooding has passed.

How are sediment load and river discharge related?

When discharge increases, sediment load increases.

Erosion caused by the impact of both small and large particles against the streambed and banks is called

abrasion

A stream is a term used to describe ______ flow of water through a channel.

any

Floods caused by the melting of snow and ice precipitation differ from floods caused by rainfall because they _______.

are delayed

Streams around the world can flow in any cardinal direction (north, south, east, and west); however, all streams flow ______. Multiple choice question.

downhill

Streams throughout the world flow

downhill

The area drained by a stream and its tributary network is called the

drainage basin

Flooding of a stream due to elevated quantities of precipitation comes from ______.

either single intense events or above average seasonal rainfall

The stream gradient is the change in ______ of the stream over the horizontal distance measured.

elevation

True or false: The flooding of streams due to precipitation events can only be caused by the sudden increase of a large volume of water from a single storm.

false

An event where water exceeds the capacity of a stream and flows onto adjacent land that is not normally covered by water is considered a(n)

flood

Sediments in floodwaters that are deposited adjacent to streams create____________ , which are broad, flat areas along the channel.

floodplains

A type of flood control measure called a(n)_______ , or diversion channel, is used when densely developed areas such as large cities decide to reroute excess water from a flood event.

floodway

A stream's , or slope, is measured by its change in elevation over a measured horizontal distance.

gradient

Large boulders in a stream or a flat, muddy bottom are two descriptions of stream channel

roughness

Stream discharge measures the volume of water that passes a certain point in one ______________. (Fill the blank with the unit of time used to measure stream discharge.)

second

Velocity varies across a stream's cross section due to friction. Friction along the banks causes the water velocity to be ______ than the velocity in the middle of the channel, where friction is less.

slower

Water is present in the hydrologic cycle in all of its physical states, which include liquid,_________ , and water vapor.

solid

Stream is the depth of water in a channel compared to a reference point and is used to measure varying water depths.

stage

Geologists use the term to account for the flow of any amount of water through a channel.

stream

In the formation of braided streams, streams with heavy loads deposit sediment in the stream channel to form sandbars or islands. Order the steps of how this occurs with the first step on top.

velocity slows heavy particles settle out velocity slows more light particles settle sandbar forms