Introducing KNOVA — A free reading app with curriculum-aligned passages on History & Science for Grades 3-8Learn More →

Stream Erosion and Deposition — Reading Comprehension

No ratings yet

Premium Resource

Grades

Standards

MS-ESS2-1

Rate this resource

Send Feedback / Report an Issue

About This Reader

This middle school science passage, aligned to NGSS MS-ESS2-1, introduces students to the dynamic processes of stream erosion and deposition. Students learn how streams, as powerful agents of change, shape landscapes through erosion, transport, and deposition of sediments. The passage examines key stream characteristics—gradient, velocity, discharge, and load—and explains how these factors influence the formation of landforms like V-shaped valleys, canyons, meanders, oxbow lakes, deltas, and alluvial fans. It explores stream development from youthful, steep channels to old, meandering rivers with broad floodplains, and addresses flooding hazards and management. The reading integrates scientific vocabulary, cause-effect chains, real-world applications, and broader Earth system principles. The resource includes a glossary, differentiated reading levels, Spanish translations, a quiz, writing prompts, and graphic organizers. Audio integration supports diverse learners. Perfect for grade 6-8 classrooms studying Earth’s surface processes and landscape evolution.

CONTENT PREVIEW

The-Colorado-River-1 — Illustration of the Colorado River flowing through the Grand Canyon

Streams are powerful natural forces that shape the surface of the Earth by breaking down rock, transporting sediments, and creating new landforms. Across the globe, rivers and streams carve valleys, move soil, and deposit materials that form features like floodplains and deltas. Understanding how streams erode and deposit material helps us predict changes to landscapes and manage hazards like flooding.

How Streams Erode and Move Sediment
The process of erosion occurs when moving water wears away soil, rock, and sediment from the land. The main factors that control stream erosion are the gradient (or slope), velocity (speed of the water), and discharge (volume of water flowing per second). For example, a stream with a steep gradient and high velocity can erode its bed quickly, forming a deep, V-shaped valley. Streams carry sediments as load, which can be dissolved in the water, suspended as tiny particles, or rolled along the bottom as bed load. The ability of a stream to transport sediment depends on its energy. Fast-moving streams can carry large rocks, while slower streams carry only fine particles. This constant movement shapes the land and redistributes sediments downstream.

Deposition and Landform Formation
When a stream loses energy—often due to a decrease in gradient or velocity—it can no longer transport all its load. This leads to deposition, where sediment settles out of the water. Over time, deposition creates landforms such as floodplains, wide flat areas alongside rivers that are covered during floods. Meanders, which are broad, looping bends in a river, form as streams erode their outer banks and deposit sediment on their inner banks. Sometimes, a meander becomes cut off, forming an oxbow lake. At a river’s mouth, deposition can build up large deltas or fan-shaped alluvial fans, like where the Mississippi River meets the Gulf of Mexico. These landforms illustrate how erosion and deposition are linked processes.

Stream Development and Flooding
Streams change over time. Young streams in steep areas erode downward rapidly, creating deep, narrow valleys and sometimes waterfalls. As streams mature, their gradients become gentler, and they start to erode sideways, forming wider valleys and extensive floodplains. Old streams flow slowly across broad, flat landscapes and have many meanders. Flooding occurs when a stream’s discharge exceeds the capacity of its channel. This can result from heavy rainfall, snowmelt, or human changes to the landscape. Floods can damage property, erode soil, and deposit nutrient-rich sediments on floodplains. Managing floodplains with levees or land-use planning is important to reduce flood hazards and protect communities.

By studying stream erosion and deposition, scientists can better understand landscape evolution, predict hazards, and make informed decisions about land and water use. These processes are essential for ecosystems and for supporting life on Earth.

Interesting Fact: The Grand Canyon in the United States was carved over millions of years by stream erosion from the Colorado River, exposing rock layers more than 1.8 billion years old!

What is the main agent of erosion discussed in the passage?

Water in streamsWindGlaciersEarthquakes

Which landform is created mainly by stream erosion?

DeltaV-shaped valleyAlluvial fanOxbow lake

What does 'discharge' mean in the context of streams?

The size of the river's mouthThe amount of water flowing per secondThe direction the water flowsThe temperature of the water

Which process happens when a stream loses energy and cannot carry its load?

ErosionDepositionEvaporationWeathering

What is a floodplain?

A steep cliff next to a riverA flat area next to a river that floodsA bend in a riverA deep lake

What is the meaning of the word 'load' in the passage?

A type of rockThe sediments carried by a streamThe river's speedThe width of the river