Prefeasibility Access Road Design-Revised
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replacing logs due to vehicle destruction, installation of additional stakes, removal of
accumulated sediment and removal of logs.
Temporary berms will be used as diversion structures, along cut and fill slopes or to
protect water bodies. They can be installed prior to construction or during
construction, but will not be installed after construction has been completed. They
will be inspected to make sure that they are not eroded and do not allow water to
flow through them.
Bales are also a temporary containment structure that will be used while
construction activities are occurring. They should also be installed prior to or during
construction. Erosion control bales will be placed in ditch bottoms or at the toe of
cut and fill slopes. Inspections will be made to insure that water is not flowing
under, through or around the bales.
Outlet traps are to be used as part of a long term erosion control plan. They are
placed at the outlets of culverts, sediment traps, or channels to prevent any high
velocity discharge from causing erosion. Outlet traps are made by placing
appropriately sized riprap to reduce water velocities before discharge.
Rock check dams can be used in channels to slow water velocities and prevent
erosion by allowing the water to flow through riprap. They will be placed on steep
grades for temporary erosion control. Correct installation is important to prevent
bypass, undermining, and washing out, so inspection will be performed during the
installation.
Gabion baskets are rectangular wire mesh baskets filled with rock at the project site
to form permeable structures. They will be used in conjunction with a variety of
other BMP’s as permanent structures to stabilize slopes and slow water velocities.
Drainage channels are permanent structures which can collect water and direct flow
offsite. They will be used in cut and flat sections of the road to collect runoff and
prevent ponding. To prevent erosion and channel failure, proper use of rock check
dams, ditch liners, and bales should be implemented.
Erosion control blankets and channel liners are a temporary method used on sloped
areas of disturbed soil. Shaping, finishing, seeding and fertilizing shall be completed
before blankets are installed. Blankets are effective in increasing re-vegetation in
disturbed areas by protecting the seedbeds, and promoting germination. They shall
be installed with perimeter anchor trenches to prevent failure.
Sediment basins are small water detention basins which allow sediment to settle out
before the water is allowed to enter streams or ditches. The sediment basin design
depends on the flow rate of the runoff and the size or amount of sediment in the
