Question 1

The competence of a mountain river is ___________ than that of a river on a floodplain because ___________ .

Accepted Answer

Competence refers to the ability of a river to transport sediment. A mountain river has a higher competence because it is steeper and has a greater gradient, allowing it to transport larger sediment particles. A river on a floodplain has a lower competence because it is flatter and has a slower flow, which limits its ability to transport larger particles.

Question 2

Why are artificial levees only useful for some flooding events?

Accepted Answer

Artificial levees are designed to hold back water during a flood event, but if the flood becomes too large and the water pressure becomes too high, it can undermine and breach the levee, causing even more damage. Therefore, artificial levees can only be useful for certain sized floods and cannot completely prevent flooding in all situations.

Question 3

The distinction between a valley and a canyon is

Accepted Answer

The main distinction between a valley and a canyon is that the sides of a canyon are generally more steep than those of a valley. Both landforms can be formed by various natural processes and may or may not be carved by water or wind. Therefore, options A, C, and D are incorrect.

Question 4

Lakes are bodies of standing water, but not all lakes contain freshwater. Why are some lakes fated to become salt lakes?

Accepted Answer

Lakes that have only inlets but no outlets, such as endorheic or closed basins, have a high probability of becoming salt lakes. As water enters the lake through the inlets, it carries minerals with it. Since there is no outlet for the water to leave, the minerals become concentrated over time, resulting in a high saline content in the lake.

Question 5

When one stream captures the flow from another stream it is called

Accepted Answer

When one stream captures the flow from another stream, it is referred to as stream piracy. This happens when a stream with a higher gradient or stronger flow captures the headwaters of a neighboring stream with a lower gradient or weaker flow.

Question 6

Why do meandering rivers meander (move) across their floodplain?

Accepted Answer

meandering rivers meander because the curved shape of the channel causes erosion on the outer bank of the curve and deposition on the inner bank, leading to the gradual shifting of the river across its floodplain. This process is known as lateral migration. Sediment deposition and erosion also play a role in shaping meandering rivers, but the curved shape is the primary factor driving their movement.

Question 7

Ephemeral streams

Accepted Answer

Ephemeral streams have flowing water either episodically or during only a portion of the year.

Question 8

The discharge of a river will increase if

Accepted Answer

The discharge of a river is the amount of water that flows through it. If it rains in the drainage basin area, more water will enter the river and increase its discharge. Slow water, lack of rainfall, and sediment settling at the bottom of the river will all decrease the discharge.

Question 9

A small mountain stream will have a ___________ competence and a __________ capacity than the Mississippi River.

Accepted Answer

The answer of A small mountain stream will have a...

Question 10

The discharge of a river traveling through a temperate region will typically ____________ downstream; the discharge of a river traveling through an arid region will typically ____________ downstream.

Accepted Answer

In a temperate region, there may be an increase in precipitation and runoff as the river flows downstream, leading to an increase in discharge. In an arid region, there may be more evaporation and less precipitation as the river flows downstream, leading to a decrease in discharge.

Question 11

In uniform sediments with a relatively constant and gentle slope at the surface, a ___________ drainage network is expected.

Accepted Answer

A dendritic drainage network is expected in uniform sediments with a relatively constant and gentle slope at the surface. This is because the dendritic pattern is a result of the underlying geology, slope, and uniform resistance to erosion.

Question 12

The base level of a tributary would become ___________ if a dam and a reservoir were constructed where it flowed into a trunk stream.

Accepted Answer

If a dam and reservoir were constructed in the tributary, it would create a barrier that prevents the water from flowing directly into the trunk stream. This would cause the water level in the tributary to rise, resulting in a higher base level.

Question 13

Ultimately, the base level of a stream valley can be no lower than the

Accepted Answer

The base level of a stream valley is the lowest point to which a stream can erode its channel. If the stream erodes its channel below the level of the body of water into which it empties (its base level), it will no longer have the energy to continue to erode downwards. The base level is typically the average elevation of the sea since most streams ultimately flow into the ocean. Therefore, the base level cannot be lower than the average elevation of the sea.

Question 14

Within a meander, where is sediment most likely to be deposited?

Accepted Answer

Sediment is most likely to be deposited on the inner banks of the meander where the water velocity is lowest. As water flows through the meander, it is forced to slow down and deposit sediment on the inner bank, which eventually leads to the formation of a point bar. Therefore, option B is the correct answer.

Question 15

Braided streams

Accepted Answer

Braided streams consist of multiple intertwined channels that are overloaded with sediment, causing them to split and rejoin frequently.

Question 16

Ephemeral streams, as opposed to permanent streams,

Accepted Answer

Ephemeral streams only contain water during rainfall and do not have a continuous flow like permanent streams. They are also sometimes called intermittent streams or seasonal streams. While they may still have a drainage basin or watershed, they do not always have water flowing within them. Ephemeral streams are found in many different regions, not just tropical ones.

Question 17

A meander that is cut off to become completely isolated from the main channel but which retains water is a(n)

Accepted Answer

When a meander becomes cut off from the main channel, it forms a U-shaped body of water that is no longer connected to the river, which is called an oxbow lake.

Question 18

The figure below shows an example of a ___________ drainage network.

Accepted Answer

The answer of The figure below shows an example of...

Question 19

What physical property of the underlying rock would lead to the formation of a cliff over which a waterfall may form?

Accepted Answer

A high resistance to erosion would make the rock more resistant to wear and tear from the water and would hold its shape better, creating a cliff over which a waterfall may form. High porosity, large permeability, and very fine grain sizes would not necessarily contribute to the formation of a cliff over which a waterfall may form.

Question 20

One way to mitigate flooding is to build ___________ , which are areas that are intended to flood and as such are not zoned for buildings.

Accepted Answer

The answer of One way to mitigate flooding is to...

Quiz 13: Freshwater: Streams, Lakes, and Groundwater

The competence of a mountain river is _ than that of a river on a floodplain because _ .