Running Water, Streams, Weathering, and Soil

60 practice flashcards covering stream dynamics, drainage patterns, flooding, weathering types, and soil formation based on the lecture notes.

What is the term for the lowest level a stream can erode to?

Base Level (usually sea level)

Which flat area beside a river floods periodically?

Floodplain

What is the formula for calculating stream gradient?

$$\text{Elevation drop} \div \text{distance}$$

What is the deepest and fastest-flowing part of a channel called?

Thalweg

Which drainage pattern resembles tree branches and occurs on uniform rock?

Dendritic

Which drainage pattern flows outward from a central high point, such as a volcano?

Radial

What drainage pattern is characterized by right-angle bends controlled by faults and joints?

Rectangular

Which drainage pattern features parallel valleys with short tributaries common in folded rock layers?

Trellis

Besides flowing in channels, what are four other ways water can exist on the surface?

Wetlands, lakes, swamps, and marshes

What two processes contribute to the formation of V-shaped valleys?

Mass wasting on valley sides and downcutting

Which stream type has multiple intertwined channels and a heavy sediment load?

Braided Stream

What is the term for a stream that flows only after rain or snowmelt?

Ephemeral Stream

What type of stream is characterized by a curvy channel?

Meandering Stream

What occurs when a pirate stream captures drainage from another stream?

Stream piracy

What does the term 'competence' refer to in a stream?

The largest particle a stream can move, controlled mostly by velocity

What does the term 'capacity' refer to in a stream?

The total amount of sediment a stream can carry, controlled mostly by discharge

Where is sediment deposited on the inner bank of a meander?

Point Bar

What is a raised bank used for flood control called?

Levee

What is the term for a dry stream channel that flows only after rain?

Arroyo

What is an easy crossing point in a stream called?

Ford

Why does a deep, narrow stream flow faster than a wide, shallow one?

It experiences less friction

What three components make up a stream's sediment load?

Dissolved load, suspended load, and bed load

How does the stream gradient typically compare near the source versus the mouth?

The gradient is greater near the source than the mouth

What happens when the velocity of a stream decreases?

Suspended sediment begins depositing

What is the primary difference between a valley and a canyon?

Canyon walls are steeper

In a waterfall cliff, why does sandstone typically form the cliff while shale erodes?

Sandstone is more resistant to erosion than shale

What is the narrow strip of land between two meander bends called?

Meander Neck

What is the outer bank of a meander where erosion occurs called?

Cut Bank

What is a cut-off meander that is filled with water called?

Oxbow Lake

What is a former stream channel that has been left behind called?

Abandoned Meander

Besides bird-foot, what are three other shapes a delta can take?

Arcuate, cuspate, and estuarine

How does discharge change downstream for a humid river versus an arid river?

Discharge increases downstream in humid rivers and decreases downstream in arid rivers

Statistically, how does a $100$-year flood compare to a $50$-year flood?

A $100$-year flood is statistically larger

If a $50$-year flood occurs in $2010$, what is the chance it will occur again in $2011$?

$$2\% \text{ (or } 1/50\text{)}$$

What are four sources of river water besides direct runoff?

Groundwater, springs, snowmelt, and glaciers

What is the name for the main river in a drainage system?

Trunk stream

Which factor causes faster flow: a steep gradient or a gentle gradient?

Steep stream gradient

Why does water flow faster in a straight channel than in meanders?

A straight channel has less resistance

What four factors primarily determine the shape of a delta?

The interaction between river sediment supply, waves, tides, and coastal currents

What is the definition of sediment?

Loose fragments of rocks and minerals broken off bedrock or precipitated from water

What are the layers within soil called?

Horizons

What is the main process that produces sediment?

Weathering

What is the relationship between physical and chemical weathering?

Physical weathering produces more surface area for chemical weathering to attack

What three materials are the results of weathering?

Sediment, dissolved materials, and soil

Why does differential weathering occur?

Different minerals have different resistances to weathering

What are vertical fractures or lines in a rock called?

Jointing

What process causes honeycomb textures in rocks, especially near coasts?

Salt weathering (salt wedging)

What is the term for onion-like rock layers peeling off due to pressure release?

Exfoliation (or sheeting)

How is physical weathering defined?

Rocks breaking apart into smaller pieces along joints and fractures

Which physical weathering process is dominant in cold climates?

Frost wedging

How does salt weathering occur near the ocean?

Salt crystals grow inside rock pores and expand

What is the definition of chemical weathering?

The interaction of rock with water or air leading to mineral transformation

What chemical weathering process turns iron-bearing minerals into rust?

Oxidation

What chemical weathering process involves minerals absorbing water and expanding?

Hydration

Which chemical weathering process involves water reacting with minerals to break them down?

Hydrolysis

What chemical weathering process occurs when minerals dissolve into water?

Dissolution

Which group of minerals, including calcite and aragonite, is most easily dissolved?

Carbonate minerals

Which soil horizon is the organic-rich top layer?

O horizon

Which soil horizon consists of weathered parent material?

C horizon

What five factors influence soil formation according to the acronym CLORPT?

Climate, Living organisms, Relief, Parent material, and Time

What event was caused by severe soil erosion during a period of wind and drought?

The Dust Bowl