Beside being referred to in the construction business, gravel are small round rocks found in a river. Their formation is caused by the river flow over time. As water flows over sediments, it smoothens the surface, which causes the rocks to be smooth and round.
River gravel is an important component for the survival of fish, particularly salmonids in British Columbia. Salmon and trout rely on gravel, which is the substrate used for spawning. Without gravel, these fish populations cannot be reproduced.