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BUILDING A
Rock ford dam on
Courtois section,
near Berryman
Campground, built
by volunteers at
the September
2010 Mega Event.
ROCK
FORD
DAM
The Ozark Trail is located
in areas crossed by many
streams and creeks. In
some locations, a safe wet
crossing is possible during
low water. In other spots,
constructing a crossing at
a shallow spot is the best
way to keep users on the
trail and get them across
the water safely.
A well-constructed rock ford dam provides a
consistent depth of water from one side to
the other, slowing the water to avoid damage
to the structure. Rock ford dams will need
minimal maintenance as they tend to self-
flush after a downpour. If deep spots develop
or debris or high water washes away parts of
the dam, restore it to the original formation.
Stream
Flow
High Water
Level
Stream Bank
Back
Slope
Downgrade
Downgrade
Embed rock dam
at least 12” into
each bank
1
STEP
1
During low
water, choose a wide,
shallow portion of the
stream, avoiding curves.
Approaches to a dam
should climb a minimum
of 12 inches above the
high water line. Purpose:
avoid water undercutting
approaches to the dam
and avoid directing water
onto the trail tread.
Install
stepping stones
on upstream
edge of tread
3
Hand-place
rocks, 130 lb.
minimum
2
Construct
tread of
gravel and
small rock
less than 3”
in size
4
STEP
2
Place large rocks in a
dam formation downstream from cen-
terline of the trail. These rocks should
be “two-man rocks” weighing at least
130 pounds each. (If one person can
lift and carry the rock to the site, they
are too small to withstand the water
pressure to be placed on them.) Embed
the anchor rocks of the dam at least 12
inches into each stream bank. Pur-
pose: provide a solid base to withstand
post-rain water pressure on the dam.
STEP
3
Arrange a row of flat
rocks, a minimum of 130 pounds
each, stepping-stone style and level,
about 12 inches apart, upstream from
the tread. Embed rocks to about 1/3
of their depth. Purpose: slow water
reaching the ford and provide alter-
nate footing for hikers.
STEP
4
Lay down
medium-sized gravel, less
than 3 inches diameter on
the ford. Purpose: even
the flow of water as it
crosses the ford and
create a level tread for
surest footing.
CAUTION: Trail users should never attempt to cross streams in high water.
Hand-Placed
Rock Dam
Install stepping stones
130 lb. minimum
Downstream
Embed 1/3 of rock depth
Typical Streambed
Construct top of dam level
High Water Level
Embed 12”
minimum
10
|
The 2013 Ozark Trail
Connector