Dynamic Planet

What percentage of Earth's water supply is freshwater?

Less than 3%

Where is the majority of Earth's freshwater stored?

In glaciers and icecaps

What is the availability of freshwater for human and animal use?

Only about 0.5% of Earth's water.

What are the three main processes involved in the weathering and erosion cycle?

Weathering (breaking down material), Erosion (Moving Away), Deposition (Dropping Off)

What does the term 'stream' refer to?

A general name for all moving water.

What is the recurrence interval of a flood?

The expected frequency of a flood event

What is considered the 'Ultimate Base Level' for rivers?

Sea level.

What is downcutting in river dynamics?

The deepening of a river channel relative to its surroundings.

What happens to sediment as a river approaches its mouth?

Sediment is deposited at lower elevations.

How does base level affect downcutting?

Base level is the closest to sea level a river can flow

What defines a waterfall in geological terms?

A morphological feature where water flows over a hard rock layer

What is a flood plain?

The flat area that is covered in water when the river rises

What is a natural levee?

A ridge formed by sediment deposited along the edge of a stream.

What is a meander?

A bend in a stream

What is a point bar?

An area where water in a meander drops alluvium on the inner bank.

What occurs during a stream cutoff?

The stream erodes through the neck of a meander

What is an ox-bow lake?

A separate body of water formed when a meander is cut off from the main stream.

What are deltas and how are they formed?

Landforms created when rivers meet large bodies of water

What are the different types of stream drainage patterns?

Dendritic, Parallel, Rectangular, Trellis, Radial, Centripetal, Deranged

What characterizes dendritic drainage?

It resembles a tree and occurs where a region has a single type of bedrock.

What is the significance of a braided stream channel?

It forms where a sediment-rich stream slows down and divides into smaller interwoven channels.

What is a meandering channel?

A channel that has a sinuosity ratio greater than 1.5

What is an anastomose channel?

A channel with multiple paths that divide and reconnect

What is the role of rock layers in determining base levels?

Rock layers can dictate the base levels at different points along a river.

What happens to a waterfall over time?

It appears to retreat as the softer layer at the base is eroded

What are the two main classifications of deltas?

Constructional and Destructional

What is a river-dominated delta?

A delta primarily shaped by river sediment deposition.

What characterizes a tide-dominated delta?

A delta influenced significantly by tidal actions.

Who developed the stream order system?

Arthur Newell Strahler

What is a first-order stream?

A stream with no tributaries.

What defines a second-order stream?

A stream formed by the joining of two first-order streams.

What is a lake?

A body of water completely surrounded by land.

What percentage of Earth's surface waters are contained in lakes?

More than 90%

What conditions are necessary for lake formation?

A natural basin with a restricted outlet and sufficient water input.

What are the two main layers of a stratified lake?

Epilimnion (upper warm layer) and Hypolimnion (lower cold layer).

What is an oligotrophic lake?

A lake with low nutrient levels and generally clear water.

What is a eutrophic lake?

A lake rich in nutrients

What are wetlands?

Areas where the ground is often saturated with water.

What type of vegetation is found in marshes?

Soft-stemmed vegetation.

What distinguishes swamps from marshes?

Swamps have woody vegetation.

What are bogs characterized by?

Spongy peat deposits and acidic water.

What is karst topography?

A landform developed from the dissolving action of water on carbonate bedrock.

What are sinkholes?

Funnel-shaped depressions formed by the collapse of surface material.

What is a karst spring?

A spring where groundwater discharges from a conduit or cave.

What is the water table?

The uppermost level of groundwater saturation.

What is groundwater?

Water that exists in the pore spaces and fractures in rock and sediment.

What is a playa?

A dry lake bed located in desert regions.

What is the primary source of nutrients in lakes?

Chemicals such as nitrates and phosphates.

What happens to lakes over geological time?

They tend to fill with sediments and may eventually disappear.

What is a mesotrophic lake?

A lake with moderate nutrient levels.

What is terrestrialization in bog formation?

When sphagnum moss grows over a lake and fills it.

What is paludification in bog formation?

When sphagnum moss blankets dry land and retains water.