1. Erosion:

* Increased erosive power: Faster water has more energy and can erode the streambed and banks more effectively. This can lead to wider, deeper channels, and the transport of larger sediments.

* Downcutting: Increased speed can cause the stream to cut downwards, deepening the channel. This is known as downcutting.

* Lateral erosion: Faster water can also erode the sides of the channel, widening it. This is known as lateral erosion.

2. Sediment Transport:

* Increased sediment transport: Faster water can carry larger and heavier sediment particles. The capacity and competence of the stream increase.

* Changes in sediment size and sorting: As the stream's speed increases, it can carry larger particles. This leads to changes in the size and sorting of the sediment transported downstream.

3. Stream Morphology:

* Steeper gradient: Faster flowing streams often have a steeper gradient, as the water has more energy to overcome resistance.

* Channel characteristics: Increased speed can lead to a wider, deeper, and more sinuous channel, with features like riffles, pools, and meanders.

* Changes in flow patterns: Faster flow can alter the patterns of water movement within the stream, such as creating faster currents in the middle of the channel and slower currents along the banks.

4. Other effects:

* Increased turbulence: Faster water creates more turbulence, which can further enhance erosion and sediment transport.

* Changes in aquatic life: Faster water can affect the types of organisms that can live in the stream, with some species adapted to faster flows and others preferring calmer waters.

* Changes in water temperature: Faster water can mix more effectively, leading to changes in water temperature.

Causes of increased stream speed:

* Increased precipitation: More rainfall or snowmelt leads to higher stream discharge, which increases speed.

* Steeper gradients: Streams flowing down steeper slopes have more gravitational potential energy, leading to faster speeds.

* Changes in channel shape: A narrower channel will force water to flow faster to maintain the same volume of flow.

* Human activities: Land use changes, such as deforestation or urbanization, can alter the amount of water entering a stream and its flow speed.

It's important to note that the specific effects of increased stream speed can vary depending on the stream's characteristics, the magnitude of the increase in speed, and other factors.