1) Describe four possible changes that may take place within a graded stream if there is an increase in gradient. Be very specific and include rock types and processes that each includes.

To determine four possible changes that may occur within a graded stream due to an increase in gradient, we need to understand the concept of a graded stream and how they respond to changes in gradient. Here is an explanation of the concept and processes involved, followed by the four possible changes:

1. Graded Streams:
A graded stream is a stream that has achieved a delicate balance between the energy of the flowing water and the resistance offered by the channel and the sediment it carries. The profile of a graded stream features a smooth, concave shape, with the stream channel adjusting to maintain equilibrium between erosion and deposition.

Possible changes due to an increase in gradient:

a) Increased erosion:
When the gradient of a stream increases, it means the stream's slope or steepness has become steeper. This increased slope leads to increased velocity, enabling the stream to erode and transport sediment more efficiently. The primary changes that may take place due to increased erosion are:
- Increased down-cutting: The stream deepens its channel through the process of vertical erosion, cutting into the underlying bedrock or sediment.
- Increased transportation of sediment: The stream has a higher capacity to transport coarser sediment, including larger rocks and boulders, due to the higher energy levels.

b) Increased bedrock exposure:
As the stream erodes the bedrock, an increase in gradient can accelerate the rate at which the underlying bedrock becomes exposed. This may cause previously buried or covered rocks to be revealed along the stream channel.

c) Increased sediment load:
When the gradient of a stream increases, it results in faster and more forceful water flow, allowing the stream to pick up and transport a greater amount of sediment. This increased sediment load may consist of various rock types such as sand, gravel, and even boulders, depending on the stream's ability to erode and the availability of sediment in its path.

d) Steeper banks and channel widening:
A higher gradient can lead to faster water flow, which increases the lateral erosion, widening the channel and steepening the stream banks. This can result in the removal of vegetation along the banks and changes to the shape of the channel.

These are some possible changes in a graded stream if there is an increase in gradient. Please note that the specific changes will depend on factors like the nature of the rock types in the stream's pathway, the amount and type of sediment available, and the overall energy of the stream.