What would decrease the competence of a stream?

What affects stream competence?

Stream capacity is the maximum amount of solid load (bed and suspended) a stream can carry. It depends on both the discharge and the velocity (since velocity affects the competence and therefore the range of particle sizes that may be transported).

What decreases stream competence?

Vegetation has a known impact on a stream’s flow, but its influence is hard to isolate. A disruption in flow will result in lower velocities, leading to a lower stream competence.

What factors affect competence and capacity?

Under normal circumstances, the major factor affecting stream capacity and stream competence is channel slope. Channel slope (also termed stream gradient) is measured as the difference in stream elevation divided by the linear distance between the two measuring points.

How can competence change in a river?

The competence of a stream refers to the maximum size of the pieces of sediment it can move. Faster-moving water has greater competence and can move larger pieces of sediment.

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.

What two major factors result in deposition in a stream channel?

The process of deposition occurs when bedload and suspended load come to rest on the bottom of the water column in a stream channel, lake, or ocean. The two major factors causing deposition are the decrease in stream gradient and the reduction in velocity.

What factors influence stream 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.

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.

Which of the following results when the velocity of a stream slows?

What is the term for sediment deposited by streams? As stream velocity slows, the smallest particles get deposited first. Streams carry most of their sediment load in the form of suspended load.

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.

Why are some streams intermittent?

Seasonal streams (intermittent) flow during certain times of the year when smaller upstream waters are flowing and when groundwater provides enough water for stream flow. Runoff from rainfall or other precipitation supplements the flow of seasonal stream.

How do velocity and discharge affects stream erosion and deposition?

The higher discharge also increases the cross-sectional area of the stream, so it fills up the channel. In a flood it may overflow the banks. Another factor that affects stream-water velocity is the size of sediments on the stream bed.

What factors affect the amount of sediment a stream can carry?

In addition to the changes in sediment load due to geology, geomorphology and organic elements, sediment transport can be altered by other external factors. The alteration to sediment transport can come from changes in water flow, water level, weather events and human influence.

Which factor does not affect stream velocity?

Answer and Explanation: The factor that does not influence stream velocity is b. stream elevation.

What generally decreases downstream along the length of a stream?

Because river slope generally decreases in a downstream direction, it is generally supposed that velocity of flow also decreases downstream. Analysis of some of the large number of velocity measurements made at stream-gaging stations demonstrates that mean velocity generally tends to increase downstream.

Why does gradient decrease downstream?

Gradient (the slope of the land) decreases as rivers flow because the river meanders across the land rather than erode into it and follow a straight path as it does in the source. This means it covers a decrease in height over a longer distance the further downstream you get.

Do streams that lose headwaters lose their ability to carry sediment?

Streams that lose velocity also lose their ability to carry sediment. 17. A streams velocity lessens and its sediment load drops when its gradient abruptly decreases.

Why does velocity increase downstream?

Discharge increases downstream because of additional water from tributaries. Velocity increases due to the additional water from tributaries and less water is in contact with the bed and banks so there is less friction. Find out more about the long profile of a river.

What decreases in downstream direction?

Because river slope generally decreases in a downstream direction, it is generally supposed that velocity of flow also decreases downstream. Analysis of some of the large number of velocity measurements made at stream-gaging stations demonstrates that mean velocity generally tends to increase downstream.

Why does river velocity decrease downstream?

As a river flows down steep slopes, the water performs vertical erosion . This form of erosion cuts down towards the river bed and carves out steep-sided V-shaped valleys. As the river flows towards the mouth, the gradient of the slope becomes less steep.

Why does load particle size decrease downstream?

This is because the further downstream material is carried then the greater the time available for it to be eroded by attrition and abrasion which makes rocks and stones smaller and rounder.

What does meander mean in geography?

a bend in

A meander is a bend in a river channel. Meanders form when water in the river erodes the banks on the outside of the channel. The water deposits sediment on the inside of the channel. Meanders only occur on flat land where the river is large and established.

Why do rocks get smaller downstream?

Attrition. Eroded rocks collide and break into smaller fragments. The edges of these rocks become smoother and more rounded. Attrition makes the particles of rock smaller.

Why does the load quantity increase downstream?

It increases downstream as more water is added to the channel by tributaries and groundwater flow and because the channel becomes more efficient with distance downstream. As velocity is also a component of discharge, the higher velocities downstream also affect it.

What are the effects of channel shape on stream efficiency?

Channel shape and texture.

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.

Why does river depth increase downstream?

The larger mass of water causes wider and deeper water channels in order to allow water in the river to flow more freely.