Appendix 4-A - Virginia Department of Conservation and Recreation ...

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No Ball
If it is not possible to make a ball or it
crumbles easily it will drain will, but will
probably not support steeper grades.
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Soil that makes a ball but will not form a
pliable ribbon has a higher clay content
and will not drain as well, but will hold
steeper grades. These soils have limited
use during wet seasons or after storm
events.
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Ball
Ribbon
Soil that can be formed into a 1” to 2” long
ribbon with thumb and forefinger has an
even higher clay content and will support
steeper grades with higher sheer forces,
but doesn’t drain well or support wet
weather use as well.
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Soil has low cohesion but best drainage
Reduce average grades by 3%
Reduce maximum running grades by 5%
Sideslopes should be at least 10% in grade to maintain
drainage
Good cohesion and good drainage
Average grades can be up to 7% and running grades
can be up to 15%
Sideslopes should be at least 20% or greater in grade
to maintain drainage
Excellent cohesion but poor drainage
Increase average grades by 3% and maximum running
grades by 5%
Armor low spots and enhance drainage features
IMBA’s Quick Soil Test
Grab a handful of soil from your proposed trail route and try
to make it into a ball. Refer to the guidance above for how
the soil does, or does not, form a ball.