Planning and implementing forest operations to achieve ... - Woodweb

• Will it fail to dissipate into the ground and Fill. Unsafe flU material is not limited to side cast
continue to travel on the surface? Water has material from the road construction on a hillside but
shown to travel downslope 2-300 meters and can also apply to fill material used to build up a road,
finally find a piece of ground to oversaturate
such as a low spot or a gully. These have the potential
with a resulting midslope failure,
to create a dam which could subsequently fail with
great environmental impact.
Having decided (in this case) that it is unsafe to place
this now concentrated flow over the bank we have in
Enhanced site productivity
the past transported it in the ditehline (which is prone
to failure) where it is introduced to the nearest Enhanced site productivity is the last of the ideals on
watercourse and now could, in an extreme case have a the list. An ideal, because not all sites can be further
detrimental effect by overloading the stream, enhanced. The aeration of compacted soil from ground
based yarding, and the specific placing of organics on
A solution successfully used by Dr. Bob Willington,
reclaimed roads can return land base to the status of a
has been to place a large french drain in the old ditch,
productive site, but it needs to be reconciled that grass
Excavated up to 1 meter diameter this drain is filled
and trees do not readily grow on bare rock or raveling
with well-draining material such as shot rock or
slopes.
cobbles, which has been wrapped, sausage-like in filter
cloth and then covered with the sidecast material,
Signa
which probably had to be pulled back also. This
engineered fi'ench drain transports the water to the
Before deactivating a road it is necessary under the
stream, but it now has the added advantage of allowing Code to post information as to the hazards that may be
a large portion of the water to return sub-surface as its expected. As well as the warning "Road Deactivated"
movement is restricted by the cobbles, rather than free- it is necessary to note any other hazards such as
flowing unrestricted down an open ditch, and a portion "Bridges Removed" etc.
isreintroduced subsurface.The french drain also
keeps the pullback material placed on it well-drained, Re-establishing natural drainage
which is an important benefit in fine textured soils.
On roads of older construction (Pre-eode) it may be
Restoring drainage on steep ground is comparatively
necessary to re-establish natural drainage patterns.
easy as the watercourse is usually obvious due to the
A stream may have been diverted from the path of its
accelerated erosion processes such as establishing
natural course:
gullies etc. However, on fiat ground the direction and • during the period of road construction,
course of small waterflows can be very difficult to find • during the maintenance phase, or
and re-establish. ° intheensuing timewhen maintenance was
abandonedand
Slope stability • drainage structures failed,
• banks sloughed into ditches,
Slope stability is the second of the requirements under • culverts plugged up.
the Forest Practices Code and is one of our most
serious liabilities in its capacity to do irreparable
However, caution must be takent That diverted
damage,
watercourse must be examined closely as it may not be
safe to plase the diverted water bask into it's old
Cut Slopes. Unstable cut slopes and unstable fill channel. There may be a number of reasons.
slopes are the two most visually obvious candidates.
The easily visible sear of the cut slope earl be unstable ° It may be decided that the new channel has
if it is not at its natural angle of repose (too steep) or
been established for long enough to now be
has stumps or boulders on it that could in time dislodge
classified as the "natural" course.
and lead to further slope movement. A rock face is not
necessarily inherently stable. This rock face could • Rechanneling the water may create an
possibly be unstable from frasturing during the blasting
environmental disturbance and/or generate
process, or incompetent rock overlying aeap. It could excessive sediment.
be the source for large pieces to break off from the
fi'eeze thaw effect and have an overall negative safety • Have a negative effect on the environment as
andenvironmental impact,
awhole.
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