Geography of Deltas and Stream Formation

Questions and Answers

How do deltas develop? Choose one.

When a small tributary enters the trunk stream

When stream velocity increases the competence of streams

When sediment-laden stream water enters standing water, like an ocean (correct)

When an area of a stream becomes influenced by tides

Which type of delta is shown in the photo below?

Bird's-foot delta

Define the discharge of a stream. Choose one.

The amount of rainfall that enters a stream from a drainage basin

The mass of water flowing through the entire stream at any given time

The velocity of water flowing at the mouth of a stream

The volume of water passing through a point on a stream per unit time (correct)

Why is the average velocity of a stream difficult to determine? Choose one.

Instruments used to measure water velocity in streams are often inaccurate. Signup and view all the answers

What factors cause the discharge of a stream to change? Choose one or more.

The size of the watershed Signup and view all the answers

What is the difference between permanent streams and ephemeral streams?

Permanent streams flow all year long; ephemeral streams flow for only part of the year. Signup and view all the answers

Which type of stream is shown in the photo below?

Ephemeral Signup and view all the answers

What is the difference between a stream's competence and capacity? Match the terms with their correct definitions.

Competence = Refers to the maximum particle size a stream can carry Capacity = Refers to the total quantity of sediment a stream can carry Signup and view all the answers

The size of the clasts that settle at a particular locality depends on how slow the flow has become. Therefore, (1)_ sediment tends to settle out upstream, where water flows faster, whereas (2) grains settle out downstream, where water flows more slowly, and the (3)_______ sediment settles out when the stream flows into a standing body of water.

1.coarser; 2.finer; 3.finest Signup and view all the answers

Does the land surface outside of the watershed slope toward or away from the drainage divide?

Away Signup and view all the answers

A stream will deposit sediment when __________.

its flow velocity decreases Signup and view all the answers

Stream sediment is deposited in a variety of settings. Which setting best describes the photo below? Choose one.

Mud deposited along a gentle, slow-moving stream Signup and view all the answers

Label the sources of water that can enter a stream.

A. Puddles, swamps, lakes; B. Groundwater; C. Melting ice or snow; D. Precipitation Signup and view all the answers

What is the difference between a slow-onset flood and a flash flood? Match the descriptions with their term.

Slow-onset floods = Flooding takes days to develop and lasts for days or weeks Flash floods = Floodwaters rise so fast that it may be difficult to escape their path Signup and view all the answers

What weather conditions can lead to flooding? Choose one or more.

A long period of continuous rain Signup and view all the answers

Downcutting in a stream a channel, and headward erosion a channel. Choose one.

Deepens; lengthens Signup and view all the answers

Label the location on this stream diagram where water is flowing fastest.

Fastest flow Signup and view all the answers

As a stream downcuts through alluvium, as shown in the diagram below, a new lower floodplain develops. The remnants of the original alluvial plain remain as a pair of _...

terraces Signup and view all the answers

Study Notes

Deltas and Stream Formation

Deltas form when sediment-laden stream water enters standing water, such as oceans, leading to sediment deposition.
Bird's-foot delta is a specific type characterized by long, protruding branches resembling a bird's foot.

Stream Discharge and Measurement

Stream discharge is defined as the volume of water passing through a specific point on a stream per unit time.
Determining average stream velocity is complex due to often inaccurate measuring instruments.

Factors Influencing Stream Discharge

Human activities, like irrigation, can alter stream discharge.
Watershed size and precipitation levels (rain or snow) significantly impact discharge rates.

Permanent vs. Ephemeral Streams

Permanent streams flow throughout the year, while ephemeral streams only flow during certain parts of the year.
Ephemeral streams typically experience flow during specific seasons or rainfall events.

Stream Competence and Capacity

Competence refers to the maximum particle size a stream can carry.
Capacity indicates the total sediment quantity a stream can transport.

Sediment Settling Dynamics

Coarser sediments settle upstream where flow is faster, while finer grains settle downstream, and the finest settle as the stream enters standing water.

Watershed Dynamics

Land surface outside a watershed slopes away from the drainage divide, directing water flow towards the divide.

Sediment Deposition

Streams deposit sediment when their flow velocity decreases, leading to sedimentation in various environments such as gentle streams and rivers entering larger bodies of water.

Water Sources to Streams

Sources of water entering streams include puddles, swamps, lakes, groundwater, melting ice or snow, and precipitation.

Flood Types

Slow-onset floods develop gradually over days, while flash floods can occur rapidly, causing swift rise in water levels that make escape difficult.

Weather Conditions Leading to Flooding

Flooding can result from abrupt, heavy rains, prolonged rainfall, or rapid snowmelt during warm spells.

Stream Erosion Processes

Downcutting deepens a stream channel, while headward erosion lengthens it, contributing to stream valley formation.

Stream Dynamics

Identifying locations of fastest water flow in a stream is crucial for understanding erosion and sediment transport processes.

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Description

Explore the fascinating processes involved in delta formation and stream dynamics. Learn about factors influencing stream discharge, measurement techniques, and the differences between permanent and ephemeral streams. This quiz covers various aspects of fluvial geography and hydrology.