Geology Hour Exam 2

What percentage of the Earth's water is contained in fluvial processes?

0.016%

What are the three major repositories of Earth's water?

Ocean, glaciers, groundwater.

What is discharge in the context of rivers and streams?

The amount of water going past a given point per unit.

What are the four types of sediment transport loads?

Bed, saltation, suspended, and dissolved.

What is the total load of sediment in a stream referred to as?

Stream capacity.

What two factors does stream capacity depend on?

Sediment availability and discharge.

What is velocity in the context of water flow?

How fast the water is moving.

What does the velocity of a stream depend on?

Discharge and gradient.

What is a drainage basin?

An area from which a stream collects water.

What does it mean if a stream is in equilibrium?

It will be concave up and in a tectonically quiet area.

How does a stream in disequilibrium appear?

It will have a portion that is convex up and will be in a tectonically active and topographically low area.

What is a flood plain?

An area where a stream meanders.

What is fast water in a river called?

Cut bank.

Where does slow water in a river cause deposition?

Point bar.

What type of stream is called an uplift?

A young stream.

What defines the size of a stream channel?

Normal stream flow.

What are the major inputs to a stream system?

Infiltration, evaporation, and runoff.

What controls flood magnitude?

Rate of runoff, amount of input, vegetation, and topography.

How do upstream floods typically behave?

They have a brief input over a limited area and cause brief localized flooding.

What happens during a downstream flood?

The main channel of the river is full.

What is a 100-year flood plain?

An area that will go underwater if a 100-year event occurs.

What are two human impacts on flooding?

Urbanization and dams.

What are methods of flood prevention?

Levees, zoning/planning, channelization, and dams.

What is a pro of flood prevention methods?

Controlling floods and generating power.

What is a con of flood prevention methods?

Habitat destruction.

What defines a trailing margin?

Has no active uplift.

What is an active margin characterized by?

Active uplift.

What factors shape the coast?

Waves, tides, and eustatic sea level.

How do waves affect the coastline?

They produce rapid and substantial changes.

What is wave base?

The depth below which no orbital motion occurs when a wave passes.

What drives tides?

The Moon.

What is wave refraction?

When waves slow down as water depth decreases.

How does longshore transport affect beaches?

Moves sediment laterally along the coast.

What are groins?

Engineered structures built perpendicular to the shore.

What are breakwaters?

Engineered structures built offshore parallel to the shoreline.

What is riprap?

A pile of walls.

What is Milankovitch theory?

About natural climate change.

What is one cycle in Milankovitch theory related to Earth's orbit?

100,000 year cycle.

How long is the tilt axis cycle in Milankovitch theory?

41,000 year cycle.

What does precession refer to in Milankovitch theory?

Time of year when the Earth is closest to the Sun, in a 23,000 year cycle.

How much warming or cooling does Milankovitch theory discuss?

5-6 degrees Celsius.

What is an important component of the greenhouse effect?

CO2 acts like a blanket.

What are some observations of climate change?

Global temperature rising, atmosphere CO2 rising, ocean pH decreasing, ocean temperature rising.

What happens to CO2 in the ocean?

It dissolves.

What can shift in ocean circulation cause?

Global scale changes.

What are Humboldt currents?

Currents formed in cold waters and upwell off the coast of South America.

What characterizes the unsaturated zone of water?

It has air and water in pore spaces.

What does the saturated zone of water contain?

Only water in pore spaces.

What do gaining streams do?

Receive water from groundwater.

What defines an aquifer?

A volume of subsurface with sufficient porosity and permeability useful to humans.

What are the two general types of aquifers?

Confined and unconfined.

What distinguishes unconfined aquifers?

They are open to the surface.

What is artesian water?

Water that flows freely out of a pipe with no power.

What is the biggest danger to a confined aquifer?

A developing zone that reduces the recharge area.

What happens when withdrawal exceeds recharge?

Water may become non-renewable.

Name one consequence of aquifer withdrawal.

Subsidence, saltwater intrusion, or loss of recharge.