Forest Road Engineering Guidebook - Ministry of Forests

Remove all surfacing
from the culvert deck
on the woods
side of the cross-ditch
WOODS
SIDE
Deactivation
direction
Install sediment
control as
required.
Remove as
directed by
site supervisor
Trench drains
Flow to fish habitat
or water supply
Remove road fill,
exposing four
corners of culvert
SECTION A
CAMP SIDE
Natural slope
Figure 26. Log stream culvert removal (non-fish stream).
Forest Road Engineering Guidebook
WOODS
SIDE
SECTION A
CAMP SIDE
After road fill and culvert deck are
removed, move machine to camp side.
Use puncheon to cross on if creek is
too wide to span with tracks
Excavate material
from behind
woods side sill
Road fill
Channel
with flow
A trench drain is a cross-ditch that has been filled in with coarse rock and
built up as the road fill is pulled back against the cut (Figure 27). The purpose
of a trench drain is to pass both surface and seepage flow across road
fill pullback. Trench drains, which are only prescribed in areas of full
(heavy) pullback, are particularly useful where all the space on the road
bench must be used for placement of road fill pullback.
Seepage from
surface and
subsurface
flows
Ditchline eliminated and
subsurface outsloped
Figure 27. Trench drain.
Extend rock blanket from
bottom of overburden to toe
of fillslope pullback
Coarse rock as
necessary to prevent
erosion at outlet
Upper surface of
adjacent pullback
material
Note: Trench extends
laterally across the
wetted stream on the
road cut or seepage
zone (3 m minimum)
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