Chapter 16 Running Water [Surface Water] 2

Base Level

The lowest point to which a stream can erode, typically at sea level when it pours into the ocean.

Local or Temporary Base Level

An interim level which can occur due to formations resistant to erosion, such as a dam or waterfall.

Longitudinal Profile of a Stream

The gradient in elevation of a stream along its length, showing changes from head to mouth.

V-Shaped Valley

Narrow valleys formed when the stream is far from base level, characterized by rapid flow and erosion.

Wide Valley

Valleys that form when the stream is near base level, exhibiting shallow gradients and slower flow.

Meandering Rivers

Rivers that follow a winding, twisting course with large bends called meanders, often found in lowlands.

Cut Bank

The zone of erosion on the outside of a river bend where the water velocity is fastest.

Point Bar

The zone of deposition on the inside of a river bend where water velocity is the slowest.

Oxbow Lake

An abandoned bend in a meandering river that has filled with water.

Meander Scar

A dry oxbow lake that was once a part of the river's meandering path.

Competency

The ability of a stream to transport sediment, which increases with faster flow.

Cutoff

When a meander is bypassed, creating a new, straighter channel for the stream.

Erosion

The process by which soil and rock are removed from the Earth's surface by natural forces, leading to downcutting in streams.

Sediment Deposition

The accumulation of sediment in a stream, typically occurring when the base level is raised or flow slows.

Down Cutting

The process by which a stream erodes its bed, deepening its channel.

Gradient

The degree of slope of a stream, influencing its velocity and erosion capability.

Floodplain

The flat area surrounding a river, formed by sediment deposition, typically during flooding.

Rapids

Sections of a stream where the water flows rapidly due to a steep gradient.

Waterfalls

Vertical drops in the course of a stream, commonly occurring at resistant rock layers.

Tectonic Uplifting

Geological processes that raise Earth's surface, influencing stream base levels and sediment deposition.

Meander Features

Specific characteristics of meanders including cut banks, point bars, and oxbow lakes.

Stream Bed

The bottom of a stream channel where sediment accumulates and the water flows.

Longitudinal Profile Changes

Alterations to the profile of a stream resulting from changes in base level.

Meandering Process

The natural evolution of straight streams to more winding shapes over time due to erosion and deposition.

High Competency

The ability of a fast-flowing stream to carry large sediments.

Low Slopes

Gentler gradients in a stream that slow down flow and lead to the formation of wide valleys.

Sediment Accumulations

Build-up of particles and materials within a stream channel, forming features like bars.

Zone of Erosion

Areas in rivers where the force of flowing water actively wears away the banks and bed.