How does the shape of a stream channel affect flow?

The shape and roughness of the channel also affect the velocity of the flowing water. A narrow channel that is V‐shaped or semicircular in cross section results in faster flow; a wide, shallow channel yields a slower flow because there is more friction between the water and the stream bed.

How does channel shape affect stream velocity?

Channel shape and roughness affect a river’s velocity. 1. Generally a narrower, more circular river channel allows faster flow of water. Broader flat channels tend to slow a river down.

What factors affect stream flow?

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.

How does the location in a stream and shape of a stream affect the speed of the water?

The speed of the water in a stream depends on its slope. The steeper the slope, the faster the water moves. Fast-moving or large streams can carry more sediment than slow-moving or small streams. Abrasion occurs as sediment in a stream collides with rock in and along the stream.

What is a stream channel shape?

streambed, also called Stream Channel, any long, narrow, sloping depression on land that is shaped by flowing water. Streambeds can range in width from a few feet for a brook to several thousand for the largest rivers.

What affects flow velocity?

The velocity of a river is determined by many factors, including the shape of its channel, the gradient of the slope that the river moves along, the volume of water that the river carries and the amount of friction caused by rough edges within the riverbed.

Which of the following channel characteristics will result in the greatest flow velocity?

Flow velocity is usually greater at the mouth of the stream than the head of the stream due to an increase in channel size, an increase in channel discharge, and a decrease in channel roughness near the mouth.

How does flow rate affect patterns of erosion and deposition in the stream?

The faster the medium flows, the larger the particles it can move. As you probably know from intuition and from experience, streams that flow rapidly tend to be turbulent (flow paths are chaotic and the water surface appears rough) and the water may be muddy.

What is the apparent relationship between stream gradient and the shape of a stream valley?

High gradient streams tend to have steep, narrow V-shaped valleys, and are referred to as young streams. Low gradient streams have wider and less rugged valleys, with a tendency for the stream to meander.

What effect does the sediment being carried by the stream have on the size and shape of the channel?

As sediment is transported down stream, the water flow helps to shape the planet’s surface by carrying away the eroded material away from some regions and depositing it in others ¹⁹.

How do moving sediments affect the channel of a stream?

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.

How does the sediment size and shape change downstream?

As the river moves from the source to the mouth – both the depth of the river and the width of the river will both increase. The load of a river will also change as it is transported and eroded along the river’s profile. As a result, the size and shape of stones will change as they journey through the river profile.

What are the effects of floods on the stream compared to average flows on erosion and moving sediment?

Flood Erosion and Deposition: As flood waters rise, the slope of the stream as it flows to its base level (e.g., the ocean or a lake) increases. Also, as stream depth increases, the hydraulic radius increases thereby making the stream more free flowing. Both of these factors lead to an increase in stream velocity.

What factors would decrease flow velocity?

Water flow in a stream is primarily related to the stream’s gradient, but it is also controlled by the geometry of the stream channel. As shown in Figure 13.14, water flow velocity is decreased by friction along the stream bed, so it is slowest at the bottom and edges and fastest near the surface and in the middle.

How does stream gradient change in the downstream direction?

As one moves along a stream in the downstream direction:

1. Discharge increases, as noted above, because water is added to the stream from tributary streams and groundwater.
2. As discharge increases, the width, depth, and average velocity of the stream increase.
3. The gradient of the stream, however, will decrease.

What happens when the speed of water in a stream decreases?

A decrease in water velocity within the inside of the channel bend results in sediments being deposited to form point bars. Meandering channels form where the gradients are low and the load is generally fine-grained.

How do streams flow?

Flowing water finds its way downhill initially as small creeks. As small creeks flow downhill they merge to form larger streams and rivers. Rivers eventually end up flowing into the oceans. If water flows to a place that is surrounded by higher land on all sides, a lake will form.

Do all streams flow into the ocean?

Small rivers and streams may join together to become larger rivers. Eventually all this water from rivers and streams will run into the ocean or an inland body of water like a lake.

What is flow of water in a channel?

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 discharge of water flowing in a channel is measured using stream gauges or can be estimated by the Manning equation. The record of flow over time is called a hydrograph.

What do you mean by stream flow?

Definition of streamflow

: water flowing in a stream channel specifically : the velocity and volume of such water.

What is Channel Flow in geography?

Channel flow – the movement of water within the river channel. This is also called a river’s discharge. Groundwater flow – the deeper movement of water through underlying permeable rock strata below the water table.

What is stream flow measurement?

Streamflow is the volumetric discharge expressed in volume per unit time (typically cubic feet per second (ft3/s) or cubic meters per second (m3/s)) that takes place in a stream or channel and varies in time and space.

Why do we measure stream flow?

Streamflow information is required to determine how much water is available in different locations so the citizens can make informed decisions about growth and to help assure there is an adequate water supply even during periods of drought.

What does the flow duration curve depend on?

A flow duration curve is a plot of discharge vs. percent of time that a particular discharge was equaled or exceeded. The area under the flow duration curve (with arithmetic scales) gives the average daily flow, and the median daily flow is the 50% value. It is useful to graph the data on probability paper.

Why is river flow important?

Flow is a function of water volume and velocity. It is important because of its impact on water quality and on the living organisms and habitats in the stream. Large, swiftly flowing rivers can receive pollution discharges and be little affected, whereas small streams have less capacity to dilute and degrade wastes.

How does stream flow affect water quality?

High streamflow may decrease water quality through increased sediment from bank erosion, disturbed streambed sediment, nutrients released from sediments, and disturbance of the physical and chemical properties of water quality.

What are the four factors that affect stream velocity and how will they affect the flow?

The velocity of a river is determined by many factors, including the shape of its channel, the gradient of the slope that the river moves along, the volume of water that the river carries and the amount of friction caused by rough edges within the riverbed.