Use the following guidelines to estimate the amount of boulders and gravel needed to build a stream.
Boulder quantity
Plan for approximately 1.5 tons (1.36 metric tons) of boulders for every 10 ft (3.05 m) of stream length.
Use a 1:2:1 ratio of large, medium, and small boulders.
Gravel quantity
Estimate the amount of gravel needed at 30% of the total boulder weight.
Example: If your stream requires 10 tons (9.07 metric tons) of boulders:
10 tons × 30% = 3 tons (2.72 metric tons) of gravel.
Note: These are general estimating guidelines. Actual quantities may vary depending on the stream's width, depth, and design.