Classifying Your Primary Streambed Material
Determine your stream’s primary bed material type below.
Understanding the primary bed material of your stream will help you to determine specific details for some of the stewardship and recovery strategies. For example, certain strategies will make different recommendations based on whether your streambed is primarily sand or primarily cobble. When determining your stream’s primary bed material, you will likely encounter more than one of the categories described below. Select that material/size that makes up the majority of your streambed. If your streambed is mostly cobble but has some boulders mixed in, select cobble as your stream’s primary bed material.
Determine your stream’s primary bed material:

What is your primary streambed material?___________________________
What does your stream’s primary bed material tell you?
The primary bed material of a stream refers the predominant size of rock or sand within the channel and along the streambanks. The streambed material affects the stream’s capacity to resist erosion, transport and deposit sediment and the general shape of the channel. Generally, streams with gravel and sand bed material are more susceptible to changes during high flow events than streams with larger bed material such as cobble and boulders. Streams with finer bed material are more likely to erode and increase the amount of sediment in the water under high energy conditions. Similar to its slope, a stream will naturally adjust with its bed material to try to find a state of stable equilibrium.