Geology Quiz 16

How does the formation of a natural levee impact flooding?

Natural levees raise the height of the stream channel, reducing the amount of flooding that will occur on the floodplain.

________ make up the suspended loads of most rivers and streams.

Silt and clay-sized detrital grains

Gradients usually decrease downstream in a major river system.

True

Stream discharge is defined as the quantity of water flowing past a specific channel location per unit time.

True

The lowest base level for most streams is sea level.

True

What is a floodplain?

a flat surface next to a river channel

What is a natural levee?

a ridge of flood deposits next to a river channel

For a meandering stream, the majority of erosion occurs _____.

at the outside of a bend

A dam and reservoir are constructed on a graded river. What will happen?

deposition upstream from the dam; channel downcutting below

Depositional landforms are created where energy of the stream __________.

has decreased

The ________ describes the movement of water through Earth's hydrosphere.

hydrologic cycle

How does urbanization (paving, etc.) affect runoff and infiltration in a small, previously forested, drainage basin?

infiltration decreases; runoff increases

Which one of the following statements is true concerning natural levees?

mostly fine sand and silt that build up during floods

Where is erosion concentrated along a meandering stream?

on the outer parts of the meander loops or bends

The term used by geologists for all water flowing in a channel is _____.

stream

What is the drop in water surface elevation divided by the distance the water flows?

stream gradient

Which of the following is the correct definition of stream gradient?

the drop in elevation of a stream divided by the distance the water travels

________ is an abandoned, cutoff, meander loop.

An oxbow

________ are components of the hydrologic cycle that release water vapor directly to the atmosphere.

Evaporation and transpiration

Natural levees are constructed of machine-compacted sand and mud; artificial levees are made of concrete.

False

Point bars are depositional features located along the outer portions of meander bends.

False