PG Chapter 16: Fluvial Processes and Floods

What are fluvial processes?

Fluvial processes refer to the erosion, transport, and deposition of sediment by rivers and streams.

Define drainage basin.

A drainage basin is an area of land where all precipitation collects and drains off into a common outlet, such as a river.

What is stream order?

Stream order is a classification system that ranks streams based on their hierarchy; first-order streams are the smallest, and higher-order streams are formed by the confluence of lower-order streams.

What is a flood recurrence interval?

A flood recurrence interval is the average time between floods of a certain size or magnitude occurring at a specific location.

Name the three primary stream channel patterns.

The three primary stream channel patterns are straight, meandering, and braided.

What are stream channel characteristics?

Stream channel characteristics include width, depth, slope, and roughness, which affect flow velocity and sediment transport.

What landforms are associated with floodplains?

Landforms associated with floodplains include levees, oxbow lakes, and natural levees.

What is the dominant agent of erosion and deposition in landscapes?

Water

What is the difference between unchanneled and channeled movement of water?

Unchanneled movement is overland flow, while channeled movement is streamflow.

How does channelization affect erosion?

Channelization increases erosion.

What role does debris play in stream erosion?

Debris increases erosion.

What is chemical weathering in the context of streams?

Chemical weathering, or corrosion, increases erosion.

What are stream orders?

A classification system where smaller streams join larger ones, with smaller order numbers being more frequent.

What does stream capacity measure?

The amount of solid material a stream can transport.

What does stream competence measure?

The maximum particle size a stream can transport.

What are perennial streams?

Streams that are permanent and found in humid regions.

What are intermittent streams?

Streams that are seasonal.

What are ephemeral streams?

Streams that depend on weather conditions.

What is the significance of floods in valley excavation?

Most valley excavation occurs during floods.

What are the four categories of stream channels?

Straight, sinuous, meandering, and braided.

What is a dendritic drainage pattern?

A treelike pattern with random merging of streams.

What is a trellis drainage pattern?

A pattern that forms in areas of hard and soft bedrock in close contact.

What is downcutting in the context of valley deepening?

The power of moving water to lower the streambed.

What is the ultimate base level for downcutting?

Sea level.

What are knickpoints?

Channel irregularities such as rapids and waterfalls.

What is the thalweg in a stream channel?

The line of highest velocity in the channel.

How does water movement vary in a meander?

Water moves fastest on the outside of curves (cut bank) and slowest on the inside (point bar).

What is delta formation?

The process where slowed flow leads to sediment deposition, forming a delta.

What is a watershed?

An area that drains to a valley.