Rivers and streams deposit sediment where the speed of the water current decreases. In rivers, deposition occurs along the inside bank of the river bend [This “area” is where water flows slower], while erosion occurs along the outside bank of the bend, where the water flows a lot faster.

Abrasion occurs as sediment in a stream collides with rock in and along the stream. Pieces of rock are chipped away and rough edges in rocks and sediments themselves become rounded. The bedrock beneath streams is also eroded by abrasion.

As large rocks are broken down into smaller pieces, gravity causes them to move downhill. Water causes more erosion than wind, gravity, or glaciers. Moving water causes soil and rock erosion. Moving water carries bits of rock and soil and deposits them in other places.

During floods, the volume and rate of stream flow increases, and erosion along the stream bed mobilizes sediments that accumulate during times of decreasing stream flow. Erosion carves the sides of stream channels, contributing sediments to streams and allowing the channel to migrate over time.

When its gradient decreases, the stream overflows its banks and broadens its channel. The decrease in gradient causes the stream to deposit its sediments, the largest first. These large sediments build a higher area around the edges of the stream channel, creating natural levees.

The material moved by erosion is sediment. Deposition occurs when the agents (wind or water) of erosion lay down sediment. Deposition changes the shape of the land. Water’s movements (both on land and underground) cause weathering and erosion, which change the land’s surface features and create underground formations.

Erosion will take place on the outer parts of the meander bends where the velocity of the stream is highest. Sediment deposition will occur along the inner meander bends where the velocity is low. Such deposition of sediment results in exposed bars, called point bars.

When a stream or river slows down, it starts dropping its sediments. Larger sediments are dropped in steep areas, but smaller sediments can still be carried. Smaller sediments are dropped as the slope becomes less steep.

Factors that influence a stream’s velocity include gradient, channel shape, and channel roughness.

In a stream, the most easily eroded particles are small sand grains between 0.2 mm and 0.5 mm. The main reason for this is that small particles, and especially the tiny grains of clay, have a strong tendency to stick together, and so are difficult to erode from the stream bed.

Stream Flow and Sediment Transport Stream velocity is the speed of the water in the stream. Units are distance per time (e.g., meters per second or feet per second). Stream velocity is greatest in midstream near the surface and is slowest along the stream bed and banks due to friction.

Mechanisms that cause changes in streamflow

• Runoff from rainfall and snowmelt.
• Evaporation from soil and surface-water bodies.
• Transpiration by vegetation.
• Ground-water discharge from aquifers.
• Ground-water recharge from surface-water bodies.
• Sedimentation of lakes and wetlands.

8 Different Types of Streams

• Alluvial Fans. When a stream leaves an area that is relatively steep and enters one that is almost entirely flat, this is called an alluvial fan.
• Braided Streams.
• Deltas.
• Ephemeral Streams.
• Intermittent Streams.
• Meandering Streams.
• Perennial Streams.
• Straight Channel Streams.

about 5 miles per hour

Low flow periods in summer allow the stream to heat up rapidly in warm weather while in the fall and winter temperatures may plummet rapidly when flow is low. Flow directly affects the amount of oxygen dissolved in the water.

Showerheads and Faucets To clean these, soak the aerator or showerhead in a bowl filled with vinegar until the deposits are gone. If showerheads or aerators don’t come clean, replace them to increase water flow. Using a water-saving showerhead can increase flow but save on water usage if installed correctly.

Streamflow, or channel runoff, is the flow of water in streams, rivers, and other channels, and is a major element of the water cycle. The record of flow over time is called a hydrograph.

Bay – an area of water bordered by land on three sides, similar to, but smaller than a gulf. Bayou – (southern US) a slow-moving stream or a marshy lake.

When a stream begins to slow down the largest of particles will be left behind first. As the velocity becomes slower the next smallest size will deposit. The smallest particles will be carried the farthest.

Rest mass. The term mass in special relativity usually refers to the rest mass of the object, which is the Newtonian mass as measured by an observer moving along with the object.

Mass doesn’t affect speed directly. It determines how quickly an object can change speed (accelerate) under the action of a given force. Lighter objects need less time to change speed by a given amount under a given force.

As an object moves faster, its mass increases. (Note: this is true if “faster” is measured relative to an observer who is also the one measuring the mass. If the person measuring the mass is moving right along with the object, s/he will not observe any change in mass.)

A glacier is a huge mass of ice that moves slowly over land. Glaciers are often called “rivers of ice.”

Most of the world’s glacial ice is found in Antarctica and Greenland, but glaciers are found on nearly every continent, even Africa….Where are glaciers located?

Australia is the only continent without glaciers. Glaciers can only survive if the average temperature is freezing or less, so in warm areas they are found at high altitude. At low altitude they are only found in high latitudes.

A glacier is a huge mass of ice that moves slowly over land. The term “glacier” comes from the French word glace (glah-SAY), which means ice. Glaciers are often called “rivers of ice.” Glaciers fall into two groups: alpine glaciers and ice sheets.