Answer the questions below to make some predictions before you use the Virtual
Stream Table tool.
1. What water flow conditions might cause a dee, narrow river channel to form
in the stream table?
2. What water flow conditions might cause a wide, highly divided river channel to form in the stream table?
3. What conditions might cause the most water and sediment to be collected at the bottom of the stream table?
1. A high velocity of water flow, combined with a high volume of water, might cause a deep, narrow river channel to form in the stream table. This could result from a steep slope or a narrow channel that restricts the flow of water.
2. A lower velocity of water flow, combined with a lower volume of water, might cause a wide, highly divided river channel to form in the stream table. This could occur when the slope is more gradual or the channel widens, allowing the water to spread out and divide into multiple channels.
3. The most water and sediment are likely to be collected at the bottom of the stream table under conditions of high velocity and high volume of water flow. This will cause the water to erode more sediment and carry it downstream, depositing it at the bottom of the channel. If there are obstructions or obstacles in the stream table, such as rocks or logs, they can also collect and trap sediment at the bottom.
1. Water flow conditions that might cause a deep, narrow river channel to form in the stream table are a high volume of water entering the stream table, a steep slope or gradient, and a lack of obstacles or vegetation that would slow down the flow of water. These conditions would result in a fast-flowing stream that can erode the stream bed and create a deep, narrow channel.
2. Water flow conditions that might cause a wide, highly divided river channel to form in the stream table are a low volume of water entering the stream table, a gentle slope or gradient, and an abundance of obstacles or vegetation that would divide the flow of water. These conditions would result in a slower-flowing stream that can deposit sediment and create multiple channels, increasing the width of the river.
3. The conditions that might cause the most water and sediment to be collected at the bottom of the stream table are a high volume of water entering the stream table, a steep slope or gradient, and a lack of obstacles or vegetation to slow down the flow of water. Additionally, the presence of fine sediment, such as silt or clay, in the water can lead to sedimentation at the bottom of the stream table. These factors would result in a faster flow of water carrying more sediment, which would deposit at the bottom due to gravity and reduced energy of the water flow.
To make predictions about the water flow conditions and their effects on the stream table, we need to consider the factors that influence the formation of different river channel shapes and the deposition of water and sediment.
1. Factors that might cause a deep, narrow river channel to form in the stream table:
- Higher water velocity: When water flow is fast, it has more erosive power, which can lead to the excavation and deepening of the river channel.
- Steep slope: A steeper slope provides more energy to the flowing water, increasing its erosive capability and resulting in a narrower and deeper channel.
- Resistance to erosion: If the stream table's substrate or sediment is resistant to erosion, the hydraulic action of the water will have a greater impact on excavating a deep channel.
To test the effects of these factors using the stream table, you can increase the water flow rate, adjust the slope of the table, or use a more resistant substrate to mimic the conditions that might cause a deep, narrow river channel.
2. Factors that might cause a wide, highly divided river channel to form in the stream table:
- Lower water velocity: Slower water flow allows sediment deposition to occur, leading to the formation of bars and islands that divide the river channel.
- Gentle slope: A gentle slope reduces the energy of the water flow, which promotes the deposition of sediment and the formation of a wider and divided channel.
- High sediment load: If the stream table is supplied with a significant amount of sediment, it can lead to aggradation, where sediment builds up in parts of the channel, resulting in a more divided and wide river channel.
To simulate the formation of a wide, highly divided channel in the stream table, you can decrease the water flow rate, adjust the slope to be more gentle, or increase the sediment load in the water supply.
3. Factors that might cause the most water and sediment to be collected at the bottom of the stream table:
- Low water velocity: When water flow slows down, it allows sediment to settle and accumulate at the bottom of the river channel.
- Wider channel: A wider channel provides more space for water and sediment to spread out and collect at the bottom.
- Gentle slope: A gentle slope reduces the energy of the water flow, allowing sediment to settle rather than being carried downstream.
To observe the most water and sediment collection at the bottom of the stream table, you can decrease the water flow velocity, increase the width of the channel, or adjust the slope to be more gentle.