HU-PHS111-Cole- CHAPTER 5 Flashcards

Questions and Answers

What is a drainage basin?

All the land area that contributes water into a stream.

What is a divide?

Separates two drainage basins.

What are the four drainage patterns?

Dendritic, radial, rectangular, trellis.

Describe the Dendritic drainage pattern.

Tree-like, controlled by the slope of the land. Signup and view all the answers

Describe the radial drainage pattern.

Goes out from the center (like sun's rays), produced from domes or volcanoes. Signup and view all the answers

Describe the rectangular drainage pattern.

On highly jointed bedrock, controlled by underlying joints and faults. Signup and view all the answers

Describe the trellis drainage pattern.

Occurs in areas of folded mountains, often with alternating weak and resistant bedrock. Signup and view all the answers

What three factors control stream velocity?

Gradient, friction, discharge. Signup and view all the answers

What is gradient in terms of stream velocity?

Slope of the stream channel. Signup and view all the answers

What is discharge?

The volume of water flowing past a point per second. Signup and view all the answers

What river has the world's largest discharge?

Amazon River. Signup and view all the answers

Where does the Mississippi river rank in terms of discharge?

Number 7. Signup and view all the answers

How do the gradient, discharge, width, depth, velocity, and sediment size of a stream change from upstream to downstream?

Gradient and sediment size decrease; discharge, depth, width, and velocity increase. Signup and view all the answers

What is the formula to calculate gradient?

Stream drop/Distance. Signup and view all the answers

What is the formula to calculate discharge?

Width x Depth x Velocity. Signup and view all the answers

What is a hydrograph?

Measures a stream's discharge over time. Signup and view all the answers

How does the discharge of a stream change after urbanization?

Lag time is decreased and peak discharge is increased for the same amount of rainfall. Signup and view all the answers

What is the ultimate base level?

Sea level. Signup and view all the answers

What are the three types of 'work' streams do?

Erosion, transportation, deposition. Signup and view all the answers

Describe deposition in streams.

Occurs when the stream's velocity is reduced; heavier particles settle out first. Signup and view all the answers

What is alluvium?

All the sediment deposited by a stream. Signup and view all the answers

What is the difference between a delta and an alluvial fan?

Delta is equivalent to an alluvial fan but forms in water. Signup and view all the answers

What do natural levees do?

Form along riverbanks from sediments deposited during floods. Signup and view all the answers

What are yazoo tributaries?

Tributaries that cannot enter a river because levees block their way. Signup and view all the answers

What is karst topography?

Caves, disappearing streams, springs, sinkholes, tower karst, natural bridges. Signup and view all the answers

What kind of rock do most caves form in?

Limestone. Signup and view all the answers

What acids are important in cave formation?

Carbonic acid and calcite. Signup and view all the answers

Where do caves form relative to the water table?

At or below it. Signup and view all the answers

What direction do the meander loops of a meandering stream move?

Laterally and downstream. Signup and view all the answers

What are stalactites?

Icicle-like pendants that hang from the ceiling of a cavern. Signup and view all the answers

What are stalagmites?

Formations that develop on the floor of a cavern. Signup and view all the answers

What is a sinkhole?

Irregular terrain punctuated with many depressions. Signup and view all the answers

What is a column in cave terminology?

When stalactites and stalagmites meet and form a single column. Signup and view all the answers

What is the effect of retention ponds on hydrographs?

Increase lag time and decrease peak discharge. Signup and view all the answers

What is an oxbow lake?

Formed in a large point bar where the sediment settles and cuts off flow to the meander. Signup and view all the answers

Study Notes

Drainage Basin and Divide

A drainage basin is the entire land area that contributes water to a stream.
A divide separates two drainage basins, directing water flow into different areas.

Drainage Patterns

Four drainage patterns exist: dendritic, radial, rectangular, and trellis.
Dendritic Pattern: Resembles a tree with branches; influenced by land slope.
Radial Pattern: Water flows outward from a central point, commonly found around domes or volcanoes.
Rectangular Pattern: Occurs in areas with jointed bedrock, influenced by joints and faults.
Trellis Pattern: Formed in folded mountain regions, characterized by alternating weak and resistant rock layers, e.g., the Appalachians.

Stream Features

Oxbow Lake: A lake formed when a meander is cut off from the main river.
Meander Scars: Remnants of dried-up oxbow lakes marking former river paths.
Point Bar: Sediment deposit on the inside of meanders.
Cut Bank: Area of erosion on the outer side of a meander.

Stream Types and Streams' Dynamics

Braided Streams: Formed when sediment load exceeds capacity, leading to multiple channels.
Young Stream: Characterized by steep slopes, no meanders, and features like rapids and waterfalls.
Mature Stream: Displays wider valleys and begins to meander as down-cutting slows.
Old Stream: Example: Mississippi River. Low gradient; significant meandering; broad floodplain.

Stream Velocity Control

Stream velocity is influenced by gradient, friction, and discharge.
Gradient: The slope of the stream channel; increased slope results in higher velocity.
Friction: Rough surfaces slow stream flow; features like trees and boulders increase friction.
Discharge: Volume of water flowing past a point; higher discharge requires increases in width, depth, or velocity.

Discharge Statistics

The Amazon River holds the record for the largest discharge globally.
The Mississippi River ranks 7th in discharge size.

Changes from Upstream to Downstream

Upstream sees decreases in gradient and sediment size, while downstream experiences increases in discharge, depth, width, and velocity.

Hydrographs and Urban Impact

A hydrograph charts a stream's discharge over time.
Urbanization generally decreases lag time and increases peak discharge, raising flood risks and lowering the water table.

Erosion and Deposition

Three primary functions of streams: erosion, transportation, and deposition.
Erosion primarily occurs during high flow periods; most prominent in upstream areas.
Transportation depends on the stream's competence (maximum particle size) and capacity (maximum load).

Alluvium and Types of Sediment Load

Alluvium refers to sediment deposited by streams.
Load types include dissolved, suspended (fine particles), and bed load (heavier particles rolling along the streambed).

Delta and Alluvial Fan

A delta forms where a stream enters a lake or ocean, leading to reduced velocity and sediment deposition.
Alluvial fans are similarly shaped deposits occurring on land.

Natural Features and Processes

Natural levees form from sediment deposited by floodwaters along riverbanks.
Backswamps: poorly drained regions behind levees.
Yazoo Tributaries: tributaries that flow parallel to rivers due to blockages by levees.

Karst Topography and Caves

Caves primarily form in limestone through the action of carbonic acid.
Key features of karst landscapes include sinkholes, springs, disappearing streams, and natural bridges.

Meandering Streams Dynamics

Meandering streams transport sediment mostly in suspension, characterized by sweeping curves.
Incised Meanders: Occur in steep valleys when base levels drop, often resulting in deeper channels.
Stalactites hang from cave ceilings, while stalagmites grow upward from cave floors; their meeting forms a column.

Important Features and Terms

Spring: Natural water flow at the intersection of the water table and ground surface.
Cutoff: A new, shorter river channel formed when a stream erodes through a narrow land section.
Column: Formed when stalactites connect with stalagmites.
Soda Straw: Hollow interior of stalactites.

Meander Evolution

Meanders move laterally and downstream, with erosion dominating the outside curve and deposition occurring on the inside curve, forming point bars.

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Description

Test your knowledge of drainage basins and their patterns with these flashcards from HU-PHS111 Chapter 5. The quiz covers key concepts such as divides and various drainage patterns like dendritic and radial. Perfect for reinforcing your understanding of hydrology concepts!